Thank you all for reply, found solution on ebay

http://cgi.ebay.com/Shutter-Release-4-Canon-EOS-10D-20D-5D-1D-1DS-RS-80N3_W0QQit\
emZ220127074755QQihZ012QQcategoryZ50489QQrdZ1QQcmdZViewItem

$10 shipped in US !!, Can't be beaten :-))

Alex


      
________________________________________________________________________________\
____
Luggage? GPS? Comic books?
Check out fitting gifts for grads at Yahoo! Search
http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz

DC-3 Dreams is pleased to announce major releases of ACP
Observatory Control Software and its free companion ACP Planner.
Together, these two programs provide complete automated observing
suitable for both astro-imaging and science.

The most obvious change in ACP itself is the new "live" web
browser interface. It was designed from scratch to be the primary
way of doing automated observing both in the observatory and
remotely. It provides simple forms for single target imaging. For
multi-target runs, we provide ACP Planner free of charge. Planner
gives you a way of visualizing target position and timing like no
other. It can be used anywhere, on your laptop while travelling
or by friends wishing to use your observatory (again, it's free).
Once you have planned your multi-target run, upload the plan via
the web and click a button. ACP handles the rest.

There is much more. For more information and a special offer,
please see: http://acp.dc3.com/acp5-rel.html

For general ACP Information, please see: http://acp.dc3.com/

And for information on ACP Planner, please see:
http://acp.dc3.com/planner.html

If you've heard that ACP is hard to use or for geeks only, forget
it! ACP Planner and ACP are easy to use, yet they are the most
flexible and powerful automation packages out there. Look at the
videos, and then get the 60 day free trial to see for yourself.

   -- Bob Denny

RegiStar is really excellent for this kind of situation.
marshall

--- In ccd-newastro@yahoogroups.com, alex me <shurik0001@...> wrote:
>
> If I stacked 70 images on one night and then 30 images
> taken from the other night, and then combined two
> resulting pictures (first stack of 70, second stack of
> 30) in phtoshop layers or any other program with
> proper tecnique, does it mean I stacked 100 images ??
>
> if no, any deailed explanation is appreciated
>
> thank you, Alex
>
> P.S. the reason I am doing that is there is a small
> shift in the camera's filed of view and all programs
> I tried failed to align them properly before stacking
> due to the additional stars either present or missing
> from the edges.
>
>
>
>
________________________________________________________________________________\
____Ready
for the edge of your seat?
> Check out tonight's top picks on Yahoo! TV.
> http://tv.yahoo.com/
>

I am using a JMI EV-2 and having some interesting problems mounting
the RoboFocus. I tried using the 3M VHB tape which has worked on my
MoonLite focuser equipped refractor, but there is so little surface
area on the JMI EV that I fear the torque of the RoboFocus will work
the mounting plate loose over time. I would appreciate hearing from
any fellow imagers that have some experience or ideas of a better way
to mount a RoboFocus motor to any of the JMI EV focusers. Thanks so
much in advance.

Frank Barrett
http://celestialwonders.com

Hi Bob,
Maybe I am just missing it, but for those of us that already own
ACP, do we just download the trial version, run the installation
over top of the existing version, and then re-enter the registration
data or is there another procedure such as unistalling the previous
version?
Thanks, Rick

--- In ccd-newastro@yahoogroups.com, Bob Denny <rdenny@...> wrote:
>
> DC-3 Dreams is pleased to announce major releases of ACP
> Observatory Control Software and its free companion ACP Planner.
> Together, these two programs provide complete automated observing
> suitable for both astro-imaging and science.
>
> The most obvious change in ACP itself is the new "live" web
> browser interface. It was designed from scratch to be the primary
> way of doing automated observing both in the observatory and
> remotely. It provides simple forms for single target imaging. For
> multi-target runs, we provide ACP Planner free of charge. Planner
> gives you a way of visualizing target position and timing like no
> other. It can be used anywhere, on your laptop while travelling
> or by friends wishing to use your observatory (again, it's free).
> Once you have planned your multi-target run, upload the plan via
> the web and click a button. ACP handles the rest.
>
> There is much more. For more information and a special offer,
> please see: http://acp.dc3.com/acp5-rel.html
>
> For general ACP Information, please see: http://acp.dc3.com/
>
> And for information on ACP Planner, please see:
> http://acp.dc3.com/planner.html
>
> If you've heard that ACP is hard to use or for geeks only, forget
> it! ACP Planner and ACP are easy to use, yet they are the most
> flexible and powerful automation packages out there. Look at the
> videos, and then get the 60 day free trial to see for yourself.
>
>   -- Bob Denny
>

Hi All,

Thank you for your replys.  Based on the answers I got what happens
if I swap guidescope to imaging scope and imaging scope to guide
scope.  So if I polar aligned with my LX200GPS which was used for
imaging and my guide scope was offset slightly and then I used my
guiding scope to image should I redo my polar alignment?

-Paul


--- In ccd-newastro@yahoogroups.com, "astronomer_c"
<astronomer_c@...> wrote:
>
> --- In ccd-newastro@yahoogroups.com, James Cottle <jim_cott@>
wrote:
> >
> > ...both guidescope and mount, although pointed at slightly
> > different places in the sky, are rigidly bound together and
> > tied to the same mount. Therefore, TRACKING is the same for
> > both, i,e, the errors like PEC and so forth apply to both
> > even though they are slightly "askew"...
>
> This is my understanding also, but within particular limits,
> due to atmospheric refraction.  That's why the guidescope
> "offset" is usually kept to as little as possible, as
> someone said, to within a couple of degrees or so.  The
> effect becomes more pronounced as the "zenith distance"
> increases, i.e., as the line of sight approaches the
> horizon.  But it's not a terribly large effect in any
> case.
>
> Gregory
>

No Paul, you shouldn't have any trouble.  You Polar Aligned your "Mount", your
OTA's sit on top of the mount which is aligned to
the sky...joe  :)



------- Original Message -------
From    : paul_lx200gps[mailto:paulskitching@...]
Sent    : 7/7/2007 6:23:38 AM
To      : ccd-newastro@yahoogroups.com
Cc      :
Subject : RE: [ccd-newastro] Re: Sighting a Guidescope

  Hi All,

Thank you for your replys.  Based on the answers I got what happens
if I swap guidescope to imaging scope and imaging scope to guide
scope.  So if I polar aligned with my LX200GPS which was used for
imaging and my guide scope was offset slightly and then I used my
guiding scope to image should I redo my polar alignment?

-Paul


--- In ccd-newastro@yahoogroups.com, "astronomer_c"
<astronomer_c@...> wrote:
>
> --- In ccd-newastro@yahoogroups.com, James Cottle <jim_cott@>
wrote:
> >
> > ...both guidescope and mount, although pointed at slightly
> > different places in the sky, are rigidly bound together and
> > tied to the same mount. Therefore, TRACKING is the same for
> > both, i,e, the errors like PEC and so forth apply to both
> > even though they are slightly "askew"...
>
> This is my understanding also, but within particular limits,
> due to atmospheric refraction.  That's why the guidescope
> "offset" is usually kept to as little as possible, as
> someone said, to within a couple of degrees or so.  The
> effect becomes more pronounced as the "zenith distance"
> increases, i.e., as the line of sight approaches the
> horizon.  But it's not a terribly large effect in any
> case.
>
> Gregory
>




Yahoo! Groups Links

Hello all,

I've been with the Newastro group since the early days but rarely
contribute. I'm writing to ask if any of you would like to
contribute your astrophotos of the following targets to be pictured
in an article on Northern Arizona astronomy in the September issue of
Sedona Monthly. You will receive printed credit for the photo but no
compensation.

Targets:

M13
M57
Sagitarius star cloud
Andromeda galaxy
Pleiades
Orion Nebula
Uranus
Venus
Saturn
Jupiter
Iridium flares


Please submit photos to m81@... and include:

Target, scope, camera
Your name

Thank you,

Rob La Pointe

I don't know about you, but Boston has had very little
imaging this summer.  So...I dug through my archives
to find some old data, and came up with M92, taken
just about a year ago with my TOA-150 and ST-2000XM.

Nothing to write home about, but I gave it a shot,
pardon the pun.  This is an RGB, with 20x1 minute and
14x2 minutes per channel (48 minutes per channel in
total).  At that time, I was still under the
impression that RGB from Boston had to be really short
(1 and 2-minute shots only).  The result was extremely
noisy and had the regular horrible gradients.

Anyhow, enough beefing, here is the shot:
http://www.flemingastrophotography.com/m92.html

    ...Neil

www.flemingastrophotography.com
   Direct from Boston - brilliant diamonds in pea soup

I just acquired an NGF-s with Robofocus and would like suggestions on
settings. The one I have on a Tak FSQ is setup as:

Backlash: 30 steps
Duty cycle 50%
Microstep pause: 5
Step size:2

Theoretically the JMI's have no backlash.
Any suggestions on settings?

Either post here or e-mail direct.

Thanks.

STU

Hi,

I wonder if somebody could tell me what kind of mounting plate should
be used with the above mentioned telecompressor (focal reducer) and an
Atik manual filter wheel.

I used to work with the appropriate mounting plate and my SXV-H9
without a problem. But recently I bought an Atik manual filter wheel
and I have problems getting the correct distance/spacing. I did some
test the last couple of night with a smaller mounting plate and some
spacer in order to get the correct distance. But I am unable to check
if the images are a bit "in" or "outside" focus.

I wrote to Gerald at Optec, but he does not have any experience with
the Atik filter wheel, so I am trying here…

Thanks for any replies or help,
Eddy

Hello everyone,
Carl Sagan once described that the distant galaxies as strewm like sea
froth on the waves of space, innumerable faint,wispy tendrils of
light. These are the galaxies. Some are solitary wanderers, most
inhabit communal clusters, huddling together, drifting endessly in the
great cosmic dark.

This is one of these huddling clusters that boggles the mind and
reminds us how very small and precious we all are. In the times that
we live, I wish that everyone could come to know the awesome and
wonderful cosmos that we are part of. Things just might change down
here on this small world.

If you have a moment please take a look and have a great week. :>)

http://www.freewebs.com/skyimager/newestimages.htm

Take care,
Bob

Hi Neil;
Ok, quit your sniffling. ;-)  That is a really nice shot. It looks
great to me.

Chuck D.
Ps. I hope you are not a Red Sox fan. I feel sorry for them after we
Tigers took them to school. <g>


--- In ccd-newastro@yahoogroups.com, Neil Fleming <neilfleming@...>
wrote:
>
> I don't know about you, but Boston has had very little
> imaging this summer.  So...I dug through my archives
> to find some old data, and came up with M92, taken
> just about a year ago with my TOA-150 and ST-2000XM.
>
> Nothing to write home about, but I gave it a shot,
> pardon the pun.  This is an RGB, with 20x1 minute and
> 14x2 minutes per channel (48 minutes per channel in
> total).  At that time, I was still under the
> impression that RGB from Boston had to be really short
> (1 and 2-minute shots only).  The result was extremely
> noisy and had the regular horrible gradients.
>
> Anyhow, enough beefing, here is the shot:
> http://www.flemingastrophotography.com/m92.html
>
>    ...Neil
>
> www.flemingastrophotography.com
>   Direct from Boston - brilliant diamonds in pea soup
>

Thanks, Chuck.  Man, what a horrible summer for
imaging so far!

Yeah, I'll stick with the Red Sox.  Still leading the
majors <g>.

    ...Neil

--- Chuck Domaracki <chuckd@...> wrote:

> Hi Neil;
> Ok, quit your sniffling. ;-)  That is a really nice
> shot. It looks
> great to me.
>
> Chuck D.
> Ps. I hope you are not a Red Sox fan. I feel sorry
> for them after we
> Tigers took them to school. <g>
>
>
> --- In ccd-newastro@yahoogroups.com, Neil Fleming
> <neilfleming@...>
> wrote:
> >
> > I don't know about you, but Boston has had very
> little
> > imaging this summer.  So...I dug through my
> archives
> > to find some old data, and came up with M92, taken
> > just about a year ago with my TOA-150 and
> ST-2000XM.
> >
> > Nothing to write home about, but I gave it a shot,
> > pardon the pun.  This is an RGB, with 20x1 minute
> and
> > 14x2 minutes per channel (48 minutes per channel
> in
> > total).  At that time, I was still under the
> > impression that RGB from Boston had to be really
> short
> > (1 and 2-minute shots only).  The result was
> extremely
> > noisy and had the regular horrible gradients.
> >
> > Anyhow, enough beefing, here is the shot:
> > http://www.flemingastrophotography.com/m92.html
> >
> >    ...Neil
> >
> > www.flemingastrophotography.com
> >   Direct from Boston - brilliant diamonds in pea
> soup
> >
>
>
>


www.flemingastrophotography.com
   Direct from Boston - brilliant diamonds in pea soup

Great job, Bob.  I'd love to try that one some day.

    ...Neil

--- Bob Birket <bobsccdimaging@...> wrote:

> Hello everyone,
> Carl Sagan once described that the distant galaxies
> as strewm like sea
> froth on the waves of space, innumerable faint,wispy
> tendrils of
> light. These are the galaxies. Some are solitary
> wanderers, most
> inhabit communal clusters, huddling together,
> drifting endessly in the
> great cosmic dark.
>
> This is one of these huddling clusters that boggles
> the mind and
> reminds us how very small and precious we all are.
> In the times that
> we live, I wish that everyone could come to know the
> awesome and
> wonderful cosmos that we are part of. Things just
> might change down
> here on this small world.
>
> If you have a moment please take a look and have a
> great week. :>)
>
> http://www.freewebs.com/skyimager/newestimages.htm
>
> Take care,
> Bob
>
>


www.flemingastrophotography.com
   Direct from Boston - brilliant diamonds in pea soup

Hi !

Have some of you guys encountered this problem when collimating a RC-
scope ?
I´m using a Takahashi collimating scope :
Secondary collimation is perfect, primary is perfect
but 2 spidervanes reflections is not perfectly aligned with each
other.(You can see 2 reflections of the vanes and as I understand
these should be aligned with each other)
If I align them, the primary is out of allignment, I can never go
further. At the same time there is one more peculiar
thing. When I have the primary mirror in collimation I can see "a
millimeter" of the secondary holder edge. It is visible approx. 90
degres of a circle. When I adjust that, so no edge is seen, the
primary is a bit out of collimation again.
I cannot move the spidervanes any further in the direction I would
like to. If I could do that all the spider reflections
would be aligned and maybe the small visible part of the secondary
edge would dissappear.

I have done the star test several times but never reach the pinpoint
stars or a perfect airy disc. If I look at the airy disc way out of
collimation it seems to be almost perfect but as soon as I go near
focus the star begins to look lik a doughnut. The perfect circle is
gone. Same thing happens if I reach a point near perfect circle and
the star is not centered in the view, when centered it no longer has
the perfect circular form.

The colliamting procedure is very easy to follow but still I cant get
it collimated.
What is wrong ?

Regards
Timo Nordberg

> Hi !
>
> Have some of you guys encountered this problem when collimating a RC-
> scope ?
> I´m using a Takahashi collimating scope :
> Secondary collimation is perfect, primary is perfect
> but 2 spidervanes reflections is not perfectly aligned with each
> other.(You can see 2 reflections of the vanes and as I understand
> these should be aligned with each other)
> If I align them, the primary is out of allignment, I can never go
> further. At the same time there is one more peculiar
> thing. When I have the primary mirror in collimation I can see "a
> millimeter" of the secondary holder edge. It is visible approx. 90
> degres of a circle. When I adjust that, so no edge is seen, the
> primary is a bit out of collimation again.
> I cannot move the spidervanes any further in the direction I would
> like to. If I could do that all the spider reflections
> would be aligned and maybe the small visible part of the secondary
> edge would dissappear.
It sounds as if your secondary is not central.

> I have done the star test several times but never reach the pinpoint
> stars or a perfect airy disc. If I look at the airy disc way out of
> collimation it seems to be almost perfect but as soon as I go near
> focus the star begins to look lik a doughnut. The perfect circle is
> gone. Same thing happens if I reach a point near perfect circle and
> the star is not centered in the view, when centered it no longer has
> the perfect circular form.
>
> The colliamting procedure is very easy to follow but still I cant get
> it collimated.
Who's 'collimating procedure'?. Most should start with you having to
mechanically centre the secondary. This is _vital_ as the first step.
http://www.rcopticalsystems.com/downloads/rcos_alignment_collimation.pdf

Section 1.1.

In fact, I 'iterated' the procedure here, aligning everything, and then
going round a second time, using the laser centering method, and
recentering the secondary, then repeating the latter collimation. It makes
a huge difference.
Has the scope ever been properly collimated, since it was last shipped?. It
is possible for things to get shifted in shipment. What are you using as a
background, to look at the annulus?. It is suprising how a change in
intensity across the light source being used for this, can translate into a
misalignment. Have you got the scope at it's normal focus position?. There
is a missprint in one set of the alignment instructions, which suggests
using the 'home' position. This results in misalignment, unless you are
terribly lucky, and have a focusser that moves exactly along the optical
axis...

Best Wishes

> Who's 'collimating procedure'?. Most should start with you having to
> mechanically centre the secondary. This is _vital_ as the first
step.
>
http://www.rcopticalsystems.com/downloads/rcos_alignment_collimation.p
df
>
> Section 1.1.
>
> In fact, I 'iterated' the procedure here, aligning everything, and
then
> going round a second time, using the laser centering method, and
> recentering the secondary, then repeating the latter collimation.
It makes
> a huge difference.
> Has the scope ever been properly collimated, since it was last
shipped?. It
> is possible for things to get shifted in shipment. What are you
using as a
> background, to look at the annulus?. It is suprising how a change in
> intensity across the light source being used for this, can
translate into a
> misalignment. Have you got the scope at it's normal focus
position?. There
> is a missprint in one set of the alignment instructions, which
suggests
> using the 'home' position. This results in misalignment, unless you
are
> terribly lucky, and have a focusser that moves exactly along the
optical
> axis...
>
Hi Roger !

I have used RC Opticals and Dave Osbornes (UK)!
They are both very similar.
The scope is brand new and it´s manufactured in Italy.

I centered the secondary holder but I know that there was a
difference of 1 millimeter from one side to the other. The spider
vane does not allow to correct this difference any further.
What I dont have is a laser collimator ! I would like to see if the
secondary spot is centered properly. This is done by the manufacturer
so I really dont know.
I use a large Moonlite focuser. See www.astroswede.com/toscano.htm
The focuser is screwed on the "bottomplate" of the RC.

The thin gap you show in figure 7 is not visible through the
Tak.colli.scope when I am collimating. Regardless background and
light sources. But if I separate the gliding tube from the front part
of the TAK.colli scope the thin light annulus is visible. But I dont
know if I have to see it ? Does it not depend on the distance between
secondary and the Tak.scope ?

First I was afraid that something was out of the optical axis, like
the focuser, but I dont think that this is the case.
What should I do next ? Do you have any suggenstions ?
Thanks for your comments !

/Timo

It's important to make sure the Spider assembly is centered mechanically with
respect to the TAK alignment scope.  You may have to remove the secondary mirror
assembly to check this.  Once the Spider assembly is confirmed centered, then
the standard collimation procedure should work fine.

   If you have run out of adjustment with the Spider vanes, it may be that the
upper ring assembly has suffered some kind of mechanical shift.  This is why I
suggested checking the Spider assembly to determine if it is properly centered.


   Mike

   ---------------------------------------------------------

Timo Eric <mybrightstar@...> wrote:

Hi !

Have some of you guys encountered this problem when collimating a RC-
scope ?
I´m using a Takahashi collimating scope :
Secondary collimation is perfect, primary is perfect
but 2 spidervanes reflections is not perfectly aligned with each
other.(You can see 2 reflections of the vanes and as I understand
these should be aligned with each other)
If I align them, the primary is out of allignment, I can never go
further. At the same time there is one more peculiar
thing. When I have the primary mirror in collimation I can see "a
millimeter" of the secondary holder edge. It is visible approx. 90
degres of a circle. When I adjust that, so no edge is seen, the
primary is a bit out of collimation again.
I cannot move the spidervanes any further in the direction I would
like to. If I could do that all the spider reflections
would be aligned and maybe the small visible part of the secondary
edge would dissappear.

I have done the star test several times but never reach the pinpoint
stars or a perfect airy disc. If I look at the airy disc way out of
collimation it seems to be almost perfect but as soon as I go near
focus the star begins to look lik a doughnut. The perfect circle is
gone. Same thing happens if I reach a point near perfect circle and
the star is not centered in the view, when centered it no longer has
the perfect circular form.

The colliamting procedure is very easy to follow but still I cant get
it collimated.
What is wrong ?

Regards
Timo Nordberg






---------------------------------
Moody friends. Drama queens. Your life? Nope! - their life, your story.
  Play Sims Stories at Yahoo! Games.

[Non-text portions of this message have been removed]

C/200 VZ13 is nearing its peak on light curve – see
http://www.aerith.net/comet/catalog/2006VZ13/2006VZ13.html
This is presently the brightest comet in the sky. It will be fading
in a week or so.

It is racing though Draco at 8.4 arc seconds per minute at magnitude
~ 8.4.  I was limited to 45 second exposures when I imaged it to
avoid blur.

Let me know what you think of the movie. Note that I have really
squashed the file size to permit rapid down load. It is only 679 kB.

It was really hard for me to stretch all the frames the same because
the high cirrus cloud layer was rapidly changing.  I had to manually
adjust each frame to match the previous one. I've probably invested
six hours in image processing and composing the web page.

Images, associated data, eyepiece view, imaging notes and *movie*
all at
http://home.att.net/~dpersyk/new.htm

Please take a look and give me some feedback.  This was quite a
processing challenge for me. Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

Thanks Neil. I didn't know how well this would turn out considering that I took
the data from the light polluted back yard. I guess it speaks well for the
sensitivity of these CCD cameras.

Bob


----- Original Message ----
From: Neil Fleming <neilfleming@...>
To: ccd-newastro@yahoogroups.com
Sent: Monday, July 9, 2007 5:01:23 PM
Subject: Re: [ccd-newastro] Sea froth on the waves of space

Great job, Bob. I'd love to try that one some day.

...Neil

--- Bob Birket <bobsccdimaging@ yahoo.com> wrote:

> Hello everyone,
> Carl Sagan once described that the distant galaxies
> as strewm like sea
> froth on the waves of space, innumerable faint,wispy
> tendrils of
> light. These are the galaxies. Some are solitary
> wanderers, most
> inhabit communal clusters, huddling together,
> drifting endessly in the
> great cosmic dark.
>
> This is one of these huddling clusters that boggles
> the mind and
> reminds us how very small and precious we all are.
> In the times that
> we live, I wish that everyone could come to know the
> awesome and
> wonderful cosmos that we are part of. Things just
> might change down
> here on this small world.
>
> If you have a moment please take a look and have a
> great week. :>)
>
> http://www.freewebs .com/skyimager/ newestimages. htm
>
> Take care,
> Bob
>
>

www.flemingastropho tography. com
Direct from Boston - brilliant diamonds in pea soup





      
________________________________________________________________________________\
____
Luggage? GPS? Comic books?
Check out fitting gifts for grads at Yahoo! Search
http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz

[Non-text portions of this message have been removed]

I have had a lot of collimation problems with my OGS F8.4 16" also.
( Star optics same as RCOS) .

The scope shows astigmatism in the star test. Also, the spider is
not evenly seen in the images and multiple small diffraction flairs
are noted on bright stars. The astigmatism issue is like the result
is the result of poor primary centering which the former owner did.
I am not so sure about the flairs.

I tried a laser to center the secondary. The secondary mirror is
accurately dotted. However, I think a laser is too crude to get an
accurate alignment. The results were poor. It is very difficult to
the laser hitting the secondary dot from the front on the scope too.

I acquired the Tak Scope. It works much nicer. I can never see light
around the secondary too unless I really offset it. I would think
the having secondary dot centered in the scope would be the accurate
enough for secondary placement.

I just demounted the scope and sent the mirrors in for recoating.
I have the tools necessary for recentering the primary to 0.001

Still I am curious how this will work out. Any tips would be
appreciated. I have seen the flair problem on other images. Most
people attribute this to a turned edge. Is this true? It is a pretty
sad statement on the quality of Star's optics.

Max

--- In ccd-newastro@yahoogroups.com, Michael Sherick
<michaelsherick@...> wrote:
>
> It's important to make sure the Spider assembly is centered
mechanically with respect to the TAK alignment scope.  You may have
to remove the secondary mirror assembly to check this.  Once the
Spider assembly is confirmed centered, then the standard collimation
procedure should work fine.
>
>   If you have run out of adjustment with the Spider vanes, it may
be that the upper ring assembly has suffered some kind of mechanical
shift.  This is why I suggested checking the Spider assembly to
determine if it is properly centered.
>
>
>   Mike
>
>   ---------------------------------------------------------
>
> Timo Eric <mybrightstar@...> wrote:
>
> Hi !
>
> Have some of you guys encountered this problem when collimating a
RC-
> scope ?
> I´m using a Takahashi collimating scope :
> Secondary collimation is perfect, primary is perfect
> but 2 spidervanes reflections is not perfectly aligned with each
> other.(You can see 2 reflections of the vanes and as I understand
> these should be aligned with each other)
> If I align them, the primary is out of allignment, I can never go
> further. At the same time there is one more peculiar
> thing. When I have the primary mirror in collimation I can see "a
> millimeter" of the secondary holder edge. It is visible approx. 90
> degres of a circle. When I adjust that, so no edge is seen, the
> primary is a bit out of collimation again.
> I cannot move the spidervanes any further in the direction I would
> like to. If I could do that all the spider reflections
> would be aligned and maybe the small visible part of the secondary
> edge would dissappear.
>
> I have done the star test several times but never reach the
pinpoint
> stars or a perfect airy disc. If I look at the airy disc way out
of
> collimation it seems to be almost perfect but as soon as I go near
> focus the star begins to look lik a doughnut. The perfect circle
is
> gone. Same thing happens if I reach a point near perfect circle
and
> the star is not centered in the view, when centered it no longer
has
> the perfect circular form.
>
> The colliamting procedure is very easy to follow but still I cant
get
> it collimated.
> What is wrong ?
>
> Regards
> Timo Nordberg
>
>
>
>
>
>
> ---------------------------------
> Moody friends. Drama queens. Your life? Nope! - their life, your
story.
>  Play Sims Stories at Yahoo! Games.
>
> [Non-text portions of this message have been removed]
>

Turned edges are pretty common on the mirrors I've seen. In fact,
thinking about it, every RC mirror set I've seen had a turned edge. An
edge mask is pretty much essential when working with these mirrors.
Installing one took care of all sorts of flaring problems caused by the
turned edges.

Ron Wodaski

maxmsm wrote:
> I have had a lot of collimation problems with my OGS F8.4 16" also.
> ( Star optics same as RCOS) .
>
> The scope shows astigmatism in the star test. Also, the spider is
> not evenly seen in the images and multiple small diffraction flairs
> are noted on bright stars. The astigmatism issue is like the result
> is the result of poor primary centering which the former owner did.
> I am not so sure about the flairs.
>
> I tried a laser to center the secondary. The secondary mirror is
> accurately dotted. However, I think a laser is too crude to get an
> accurate alignment. The results were poor. It is very difficult to
> the laser hitting the secondary dot from the front on the scope too.
>
> I acquired the Tak Scope. It works much nicer. I can never see light
> around the secondary too unless I really offset it. I would think
> the having secondary dot centered in the scope would be the accurate
> enough for secondary placement.
>
> I just demounted the scope and sent the mirrors in for recoating.
> I have the tools necessary for recentering the primary to 0.001
>
> Still I am curious how this will work out. Any tips would be
> appreciated. I have seen the flair problem on other images. Most
> people attribute this to a turned edge. Is this true? It is a pretty
> sad statement on the quality of Star's optics.
>
> Max
>
> --- In ccd-newastro@yahoogroups.com, Michael Sherick
> <michaelsherick@...> wrote:
>
>> It's important to make sure the Spider assembly is centered
>>
> mechanically with respect to the TAK alignment scope.  You may have
> to remove the secondary mirror assembly to check this.  Once the
> Spider assembly is confirmed centered, then the standard collimation
> procedure should work fine.
>
>>
>>   If you have run out of adjustment with the Spider vanes, it may
>>
> be that the upper ring assembly has suffered some kind of mechanical
> shift.  This is why I suggested checking the Spider assembly to
> determine if it is properly centered.
>
>>
>>
>>   Mike
>>
>>   ---------------------------------------------------------
>>
>> Timo Eric <mybrightstar@...> wrote:
>>
>> Hi !
>>
>> Have some of you guys encountered this problem when collimating a
>>
> RC-
>
>> scope ?
>> I´m using a Takahashi collimating scope :
>> Secondary collimation is perfect, primary is perfect
>> but 2 spidervanes reflections is not perfectly aligned with each
>> other.(You can see 2 reflections of the vanes and as I understand
>> these should be aligned with each other)
>> If I align them, the primary is out of allignment, I can never go
>> further. At the same time there is one more peculiar
>> thing. When I have the primary mirror in collimation I can see "a
>> millimeter" of the secondary holder edge. It is visible approx. 90
>> degres of a circle. When I adjust that, so no edge is seen, the
>> primary is a bit out of collimation again.
>> I cannot move the spidervanes any further in the direction I would
>> like to. If I could do that all the spider reflections
>> would be aligned and maybe the small visible part of the secondary
>> edge would dissappear.
>>
>> I have done the star test several times but never reach the
>>
> pinpoint
>
>> stars or a perfect airy disc. If I look at the airy disc way out
>>
> of
>
>> collimation it seems to be almost perfect but as soon as I go near
>> focus the star begins to look lik a doughnut. The perfect circle
>>
> is
>
>> gone. Same thing happens if I reach a point near perfect circle
>>
> and
>
>> the star is not centered in the view, when centered it no longer
>>
> has
>
>> the perfect circular form.
>>
>> The colliamting procedure is very easy to follow but still I cant
>>
> get
>
>> it collimated.
>> What is wrong ?
>>
>> Regards
>> Timo Nordberg
>>
>>
>>
>>
>>
>>
>> ---------------------------------
>> Moody friends. Drama queens. Your life? Nope! - their life, your
>>
> story.
>
>>  Play Sims Stories at Yahoo! Games.
>>
>> [Non-text portions of this message have been removed]
>>
>>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>

Thanks Ron.

All the Atms and commercial newtonian mirror makers take great pride
in producing a mirror without TDE. It is a pretty basic task if you
ever have made a mirror.

It is very sad considering the cost of these optics. It also shows
what a distortion your inferometry report maybe. Inferometry usually
does a poor job evaluateing the last 1/4-1/8 inch of the edge.
However, it never should be the sole test of the optics in
fabrication.

"Caveat emptor"

Max
--- In ccd-newastro@yahoogroups.com, Yahoo - Wodaski <yahoo@...>
wrote:
>
> Turned edges are pretty common on the mirrors I've seen. In fact,
> thinking about it, every RC mirror set I've seen had a turned
edge. An
> edge mask is pretty much essential when working with these
mirrors.
> Installing one took care of all sorts of flaring problems caused
by the
> turned edges.
>
> Ron Wodaski
>
> maxmsm wrote:
> > I have had a lot of collimation problems with my OGS F8.4 16"
also.
> > ( Star optics same as RCOS) .
> >
> > The scope shows astigmatism in the star test. Also, the spider
is
> > not evenly seen in the images and multiple small diffraction
flairs
> > are noted on bright stars. The astigmatism issue is like the
result
> > is the result of poor primary centering which the former owner
did.
> > I am not so sure about the flairs.
> >
> > I tried a laser to center the secondary. The secondary mirror is
> > accurately dotted. However, I think a laser is too crude to get
an
> > accurate alignment. The results were poor. It is very difficult
to
> > the laser hitting the secondary dot from the front on the scope
too.
> >
> > I acquired the Tak Scope. It works much nicer. I can never see
light
> > around the secondary too unless I really offset it. I would
think
> > the having secondary dot centered in the scope would be the
accurate
> > enough for secondary placement.
> >
> > I just demounted the scope and sent the mirrors in for recoating.
> > I have the tools necessary for recentering the primary to 0.001
> >
> > Still I am curious how this will work out. Any tips would be
> > appreciated. I have seen the flair problem on other images. Most
> > people attribute this to a turned edge. Is this true? It is a
pretty
> > sad statement on the quality of Star's optics.
> >
> > Max
> >
> > --- In ccd-newastro@yahoogroups.com, Michael Sherick
> > <michaelsherick@> wrote:
> >
> >> It's important to make sure the Spider assembly is centered
> >>
> > mechanically with respect to the TAK alignment scope.  You may
have
> > to remove the secondary mirror assembly to check this.  Once the
> > Spider assembly is confirmed centered, then the standard
collimation
> > procedure should work fine.
> >
> >>
> >>   If you have run out of adjustment with the Spider vanes, it
may
> >>
> > be that the upper ring assembly has suffered some kind of
mechanical
> > shift.  This is why I suggested checking the Spider assembly to
> > determine if it is properly centered.
> >
> >>
> >>
> >>   Mike
> >>
> >>   ---------------------------------------------------------
> >>
> >> Timo Eric <mybrightstar@> wrote:
> >>
> >> Hi !
> >>
> >> Have some of you guys encountered this problem when collimating
a
> >>
> > RC-
> >
> >> scope ?
> >> I´m using a Takahashi collimating scope :
> >> Secondary collimation is perfect, primary is perfect
> >> but 2 spidervanes reflections is not perfectly aligned with
each
> >> other.(You can see 2 reflections of the vanes and as I
understand
> >> these should be aligned with each other)
> >> If I align them, the primary is out of allignment, I can never
go
> >> further. At the same time there is one more peculiar
> >> thing. When I have the primary mirror in collimation I can
see "a
> >> millimeter" of the secondary holder edge. It is visible approx.
90
> >> degres of a circle. When I adjust that, so no edge is seen, the
> >> primary is a bit out of collimation again.
> >> I cannot move the spidervanes any further in the direction I
would
> >> like to. If I could do that all the spider reflections
> >> would be aligned and maybe the small visible part of the
secondary
> >> edge would dissappear.
> >>
> >> I have done the star test several times but never reach the
> >>
> > pinpoint
> >
> >> stars or a perfect airy disc. If I look at the airy disc way
out
> >>
> > of
> >
> >> collimation it seems to be almost perfect but as soon as I go
near
> >> focus the star begins to look lik a doughnut. The perfect
circle
> >>
> > is
> >
> >> gone. Same thing happens if I reach a point near perfect circle
> >>
> > and
> >
> >> the star is not centered in the view, when centered it no
longer
> >>
> > has
> >
> >> the perfect circular form.
> >>
> >> The colliamting procedure is very easy to follow but still I
cant
> >>
> > get
> >
> >> it collimated.
> >> What is wrong ?
> >>
> >> Regards
> >> Timo Nordberg
> >>
> >>
> >>
> >>
> >>
> >>
> >> ---------------------------------
> >> Moody friends. Drama queens. Your life? Nope! - their life,
your
> >>
> > story.
> >
> >>  Play Sims Stories at Yahoo! Games.
> >>
> >> [Non-text portions of this message have been removed]
> >>
> >>
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>

Some things to note:

* Hyperbolic mirrors are harder to make than the parabolic and spherical
mirrors typically found in Newtonians. So comparing the two is not
strictly an even comparison.

* I've been project manager on RC mirror sets priced at as much as
$400,000. I was told by some very highly qualified optical experts
(these guys have designed optics in the multi-meter category) that
getting a turned edge on these hyperbolic mirror sets is simply not
possible. However, with careful attention to detail, the turned edge can
be as small as a few millimeters. A beveled edge and possibly a mirror
mask will take care of this small turned edge. So even very expensive RC
optics have to deal with this issue. (I suspect that the issue has to do
in part with mirror size. With a small mirror, the size of the turned
edge will be very small, and the typical beveled edge will deal with it
completely.)

That said, some of the turned edges I have seen have been way too large,
on the order of as much as an inch of _radius_ - that is extremely,
extremely large. A turned edge on the order of 2-4mm should be
considered normal; anything larger, you will certainly want a primary
mask to mask off the turned edge.

Note that most RC primary blanks are made oversize to accommodate the
small turned edge (even after beveling/masking, you will still have a
mirror as large or larger than your specified size.

Here's something to watch out for with interferograms: not including key
portions of the mirror! I've seen interferograms that left out not just
a bit of the outer and inner edges, but as much as half of the mirror! I
saw one interferogram that included only the middle third of the mirror
radius. Ouch!

I had one client who received an interferogram for a 24" mirror that
looked good but we noted that the interferogram was taken while the
mirror was fully supported on the block it was polished on. We asked for
a new interferogram of the mirror on the support that would be used in
the telescope - and the telescope manufacturer turned us down flat!

This area is _definitely_ one for "buyer beware." You must always look
at what you are getting very carefully.

Ron Wodaski

maxmsm wrote:
> Thanks Ron.
>
> All the Atms and commercial newtonian mirror makers take great pride
> in producing a mirror without TDE. It is a pretty basic task if you
> ever have made a mirror.
>
> It is very sad considering the cost of these optics. It also shows
> what a distortion your inferometry report maybe. Inferometry usually
> does a poor job evaluateing the last 1/4-1/8 inch of the edge.
> However, it never should be the sole test of the optics in
> fabrication.
>
> "Caveat emptor"
>
> Max
> --- In ccd-newastro@yahoogroups.com, Yahoo - Wodaski <yahoo@...>
> wrote:
>
>> Turned edges are pretty common on the mirrors I've seen. In fact,
>> thinking about it, every RC mirror set I've seen had a turned
>>
> edge. An
>
>> edge mask is pretty much essential when working with these
>>
> mirrors.
>
>> Installing one took care of all sorts of flaring problems caused
>>
> by the
>
>> turned edges.
>>
>> Ron Wodaski
>>
>> maxmsm wrote:
>>
>>> I have had a lot of collimation problems with my OGS F8.4 16"
>>>
> also.
>
>>> ( Star optics same as RCOS) .
>>>
>>> The scope shows astigmatism in the star test. Also, the spider
>>>
> is
>
>>> not evenly seen in the images and multiple small diffraction
>>>
> flairs
>
>>> are noted on bright stars. The astigmatism issue is like the
>>>
> result
>
>>> is the result of poor primary centering which the former owner
>>>
> did.
>
>>> I am not so sure about the flairs.
>>>
>>> I tried a laser to center the secondary. The secondary mirror is
>>> accurately dotted. However, I think a laser is too crude to get
>>>
> an
>
>>> accurate alignment. The results were poor. It is very difficult
>>>
> to
>
>>> the laser hitting the secondary dot from the front on the scope
>>>
> too.
>
>>> I acquired the Tak Scope. It works much nicer. I can never see
>>>
> light
>
>>> around the secondary too unless I really offset it. I would
>>>
> think
>
>>> the having secondary dot centered in the scope would be the
>>>
> accurate
>
>>> enough for secondary placement.
>>>
>>> I just demounted the scope and sent the mirrors in for recoating.
>>> I have the tools necessary for recentering the primary to 0.001
>>>
>>> Still I am curious how this will work out. Any tips would be
>>> appreciated. I have seen the flair problem on other images. Most
>>> people attribute this to a turned edge. Is this true? It is a
>>>
> pretty
>
>>> sad statement on the quality of Star's optics.
>>>
>>> Max
>>>
>>> --- In ccd-newastro@yahoogroups.com, Michael Sherick
>>> <michaelsherick@> wrote:
>>>
>>>
>>>> It's important to make sure the Spider assembly is centered
>>>>
>>>>
>>> mechanically with respect to the TAK alignment scope.  You may
>>>
> have
>
>>> to remove the secondary mirror assembly to check this.  Once the
>>> Spider assembly is confirmed centered, then the standard
>>>
> collimation
>
>>> procedure should work fine.
>>>
>>>
>>>>
>>>>   If you have run out of adjustment with the Spider vanes, it
>>>>
> may
>
>>>>
>>>>
>>> be that the upper ring assembly has suffered some kind of
>>>
> mechanical
>
>>> shift.  This is why I suggested checking the Spider assembly to
>>> determine if it is properly centered.
>>>
>>>
>>>>
>>>>
>>>>   Mike
>>>>
>>>>   ---------------------------------------------------------
>>>>
>>>> Timo Eric <mybrightstar@> wrote:
>>>>
>>>> Hi !
>>>>
>>>> Have some of you guys encountered this problem when collimating
>>>>
> a
>
>>>>
>>>>
>>> RC-
>>>
>>>
>>>> scope ?
>>>> I´m using a Takahashi collimating scope :
>>>> Secondary collimation is perfect, primary is perfect
>>>> but 2 spidervanes reflections is not perfectly aligned with
>>>>
> each
>
>>>> other.(You can see 2 reflections of the vanes and as I
>>>>
> understand
>
>>>> these should be aligned with each other)
>>>> If I align them, the primary is out of allignment, I can never
>>>>
> go
>
>>>> further. At the same time there is one more peculiar
>>>> thing. When I have the primary mirror in collimation I can
>>>>
> see "a
>
>>>> millimeter" of the secondary holder edge. It is visible approx.
>>>>
> 90
>
>>>> degres of a circle. When I adjust that, so no edge is seen, the
>>>> primary is a bit out of collimation again.
>>>> I cannot move the spidervanes any further in the direction I
>>>>
> would
>
>>>> like to. If I could do that all the spider reflections
>>>> would be aligned and maybe the small visible part of the
>>>>
> secondary
>
>>>> edge would dissappear.
>>>>
>>>> I have done the star test several times but never reach the
>>>>
>>>>
>>> pinpoint
>>>
>>>
>>>> stars or a perfect airy disc. If I look at the airy disc way
>>>>
> out
>
>>>>
>>>>
>>> of
>>>
>>>
>>>> collimation it seems to be almost perfect but as soon as I go
>>>>
> near
>
>>>> focus the star begins to look lik a doughnut. The perfect
>>>>
> circle
>
>>>>
>>>>
>>> is
>>>
>>>
>>>> gone. Same thing happens if I reach a point near perfect circle
>>>>
>>>>
>>> and
>>>
>>>
>>>> the star is not centered in the view, when centered it no
>>>>
> longer
>
>>>>
>>>>
>>> has
>>>
>>>
>>>> the perfect circular form.
>>>>
>>>> The colliamting procedure is very easy to follow but still I
>>>>
> cant
>
>>>>
>>>>
>>> get
>>>
>>>
>>>> it collimated.
>>>> What is wrong ?
>>>>
>>>> Regards
>>>> Timo Nordberg
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ---------------------------------
>>>> Moody friends. Drama queens. Your life? Nope! - their life,
>>>>
> your
>
>>>>
>>>>
>>> story.
>>>
>>>
>>>>  Play Sims Stories at Yahoo! Games.
>>>>
>>>> [Non-text portions of this message have been removed]
>>>>
>>>>
>>>>
>>>
>>>
>>> Yahoo! Groups Links
>>>
>>>
>>>
>>>
>>>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>

"You can see 2 reflections of the vanes and as I understand
these should be aligned with each other"

Yes they should line up. On my OGS the spider can vains can rotated
slightly. When this is done I see a clean single out line for each
vain in the take scope. This can be done independently from
centering the secondary.

"I have done the star test several times but never reach the
pinpoint stars or a perfect airy disc. If I look at the airy disc
way out of collimation it seems to be almost perfect but as soon as
I go near focus the star begins to look lik a doughnut"

If you start focusing on the star and looks like a oval on both
sides of foucus your may be seeing astigmatism. The pattern may look
concentric until you are near focus. If it is astig. the oval will
be reversed 90 degrees on either side of focus.

In RC's, the centering of the optics are critical. If you are sure
your getting secondary centered and collimated than the primary
maybe miscentered.

Unless you have the proper tools to center the primary would have to
ship it back. I am struggling with these same issues so I know how
frustrating this is.

I would like here from anyone that has take their RC apart and done
it from scrach. Sometimes the primary mananges to slip a little and
send the hole scope back can be a pain and expensive. It only take 1-
2 thousands of shift to get some noticible astigmatism.

Max




--- In ccd-newastro@yahoogroups.com, "Timo Eric" <mybrightstar@...>
wrote:
>
>
> Hi !
>
> Have some of you guys encountered this problem when collimating a
RC-
> scope ?
> I´m using a Takahashi collimating scope :
> Secondary collimation is perfect, primary is perfect
> but 2 spidervanes reflections is not perfectly aligned with each
> other.(You can see 2 reflections of the vanes and as I understand
> these should be aligned with each other)
> If I align them, the primary is out of allignment, I can never go
> further. At the same time there is one more peculiar
> thing. When I have the primary mirror in collimation I can see "a
> millimeter" of the secondary holder edge. It is visible approx. 90
> degres of a circle. When I adjust that, so no edge is seen, the
> primary is a bit out of collimation again.
> I cannot move the spidervanes any further in the direction I would
> like to. If I could do that all the spider reflections
> would be aligned and maybe the small visible part of the secondary
> edge would dissappear.
>
> I have done the star test several times but never reach the
pinpoint
> stars or a perfect airy disc. If I look at the airy disc way out
of
> collimation it seems to be almost perfect but as soon as I go near
> focus the star begins to look lik a doughnut. The perfect circle
is
> gone. Same thing happens if I reach a point near perfect circle
and
> the star is not centered in the view, when centered it no longer
has
> the perfect circular form.
>
> The colliamting procedure is very easy to follow but still I cant
get
> it collimated.
> What is wrong ?
>
> Regards
> Timo Nordberg
>

Some things to note:

  Hyperbolic mirrors are harder to make than the parabolic and
spherical
mirrors typically found in Newtonians. So comparing the two is not
strictly an even comparison.

-Agreed Ron

  I've been project manager on RC mirror sets priced at as much as
$400,000. I was told by some very highly qualified optical experts
(these guys have designed optics in the multi-meter category) that
getting a turned edge on these hyperbolic mirror sets is simply not
possible.

--It is quite difficult--

--Beveling, masking, using oversized mirrors is a reasonible
practice. However, your mask, bevel etc should be in place before
you get the scope. It really should be indentified by the optician.

1/25 RMS or Strehl of about 94% wavefront is what I expecting
( if that is stated specs.) It really doesnt matter where the zones
are.

-It is just sad I hear about TDEs since are cost effective approachs.
-No one should have to pull there RC apart to mask or paint out the
edge themselves. Likewise, if you paying for 16" optic usuable
aperature that what you should have. Give or take a 2-3mm.

Max



However, with careful attention to detail, the turned edge can be as
small as a few millimeters. A beveled edge and possibly a mirror
mask will take care of this small turned edge. So even very
expensive RC optics have to deal with this issue. (I suspect that
the issue has to do in part with mirror size. With a small mirror,
the size of the turned edge will be very small, and the typical
beveled edge will deal with it completely.
That said, some of the turned edges I have seen have been way too
large,
on the order of as much as an inch of _radius_ - that is extremely,
extremely large. A turned edge on the order of 2-4mm should be
considered normal; anything larger, you will certainly want a
primary mask to mask off the turned edge.
Note that most RC primary blanks are made oversize to accommodate
the small turned edge (even after beveling/masking, you will still
have a mirror as large or larger than your specified size.
Here's something to watch out for with interferograms: not including
key portions of the mirror! I've seen interferograms that left out
not just a bit of the outer and inner edges, but as much as half of
the mirror! I saw one interferogram that included only the middle
third of the mirror radius. Ouch!
I had one client who received an interferogram for a 24" mirror that
looked good but we noted that the interferogram was taken while the
mirror was fully supported on the block it was polished on. We asked
for a new interferogram of the mirror on the support that would be
used in the telescope - and the telescope manufacturer turned us
down flat! This area is _definitely_ one for "buyer beware." You
must always look
at what you are getting very carefully.

Ron Wodaski

> maxmsm wrote:
> > Thanks Ron.
> >
> > All the Atms and commercial newtonian mirror makers take great
pride
> > in producing a mirror without TDE. It is a pretty basic task if
you
> > ever have made a mirror.
> >
> > It is very sad considering the cost of these optics. It also
shows
> > what a distortion your inferometry report maybe. Inferometry
usually
> > does a poor job evaluateing the last 1/4-1/8 inch of the edge.
> > However, it never should be the sole test of the optics in
> > fabrication.
> >
> > "Caveat emptor"
> >
> > Max
> > --- In ccd-newastro@yahoogroups.com, Yahoo - Wodaski <yahoo@>
> > wrote:
> >
> >> Turned edges are pretty common on the mirrors I've seen. In
fact,
> >> thinking about it, every RC mirror set I've seen had a turned
> >>
> > edge. An
> >
> >> edge mask is pretty much essential when working with these
> >>
> > mirrors.
> >
> >> Installing one took care of all sorts of flaring problems
caused
> >>
> > by the
> >
> >> turned edges.
> >>
> >> Ron Wodaski
> >>
> >> maxmsm wrote:
> >>
> >>> I have had a lot of collimation problems with my OGS F8.4 16"
> >>>
> > also.
> >
> >>> ( Star optics same as RCOS) .
> >>>
> >>> The scope shows astigmatism in the star test. Also, the spider
> >>>
> > is
> >
> >>> not evenly seen in the images and multiple small diffraction
> >>>
> > flairs
> >
> >>> are noted on bright stars. The astigmatism issue is like the
> >>>
> > result
> >
> >>> is the result of poor primary centering which the former owner
> >>>
> > did.
> >
> >>> I am not so sure about the flairs.
> >>>
> >>> I tried a laser to center the secondary. The secondary mirror
is
> >>> accurately dotted. However, I think a laser is too crude to
get
> >>>
> > an
> >
> >>> accurate alignment. The results were poor. It is very
difficult
> >>>
> > to
> >
> >>> the laser hitting the secondary dot from the front on the
scope
> >>>
> > too.
> >
> >>> I acquired the Tak Scope. It works much nicer. I can never see
> >>>
> > light
> >
> >>> around the secondary too unless I really offset it. I would
> >>>
> > think
> >
> >>> the having secondary dot centered in the scope would be the
> >>>
> > accurate
> >
> >>> enough for secondary placement.
> >>>
> >>> I just demounted the scope and sent the mirrors in for
recoating.
> >>> I have the tools necessary for recentering the primary to 0.001
> >>>
> >>> Still I am curious how this will work out. Any tips would be
> >>> appreciated. I have seen the flair problem on other images.
Most
> >>> people attribute this to a turned edge. Is this true? It is a
> >>>
> > pretty
> >
> >>> sad statement on the quality of Star's optics.
> >>>
> >>> Max
> >>>
> >>> --- In ccd-newastro@yahoogroups.com, Michael Sherick
> >>> <michaelsherick@> wrote:
> >>>
> >>>
> >>>> It's important to make sure the Spider assembly is centered
> >>>>
> >>>>
> >>> mechanically with respect to the TAK alignment scope.  You may
> >>>
> > have
> >
> >>> to remove the secondary mirror assembly to check this.  Once
the
> >>> Spider assembly is confirmed centered, then the standard
> >>>
> > collimation
> >
> >>> procedure should work fine.
> >>>
> >>>
> >>>>
> >>>>   If you have run out of adjustment with the Spider vanes, it
> >>>>
> > may
> >
> >>>>
> >>>>
> >>> be that the upper ring assembly has suffered some kind of
> >>>
> > mechanical
> >
> >>> shift.  This is why I suggested checking the Spider assembly
to
> >>> determine if it is properly centered.
> >>>
> >>>
> >>>>
> >>>>
> >>>>   Mike
> >>>>
> >>>>   ---------------------------------------------------------
> >>>>
> >>>> Timo Eric <mybrightstar@> wrote:
> >>>>
> >>>> Hi !
> >>>>
> >>>> Have some of you guys encountered this problem when
collimating
> >>>>
> > a
> >
> >>>>
> >>>>
> >>> RC-
> >>>
> >>>
> >>>> scope ?
> >>>> I´m using a Takahashi collimating scope :
> >>>> Secondary collimation is perfect, primary is perfect
> >>>> but 2 spidervanes reflections is not perfectly aligned with
> >>>>
> > each
> >
> >>>> other.(You can see 2 reflections of the vanes and as I
> >>>>
> > understand
> >
> >>>> these should be aligned with each other)
> >>>> If I align them, the primary is out of allignment, I can
never
> >>>>
> > go
> >
> >>>> further. At the same time there is one more peculiar
> >>>> thing. When I have the primary mirror in collimation I can
> >>>>
> > see "a
> >
> >>>> millimeter" of the secondary holder edge. It is visible
approx.
> >>>>
> > 90
> >
> >>>> degres of a circle. When I adjust that, so no edge is seen,
the
> >>>> primary is a bit out of collimation again.
> >>>> I cannot move the spidervanes any further in the direction I
> >>>>
> > would
> >
> >>>> like to. If I could do that all the spider reflections
> >>>> would be aligned and maybe the small visible part of the
> >>>>
> > secondary
> >
> >>>> edge would dissappear.
> >>>>
> >>>> I have done the star test several times but never reach the
> >>>>
> >>>>
> >>> pinpoint
> >>>
> >>>
> >>>> stars or a perfect airy disc. If I look at the airy disc way
> >>>>
> > out
> >
> >>>>
> >>>>
> >>> of
> >>>
> >>>
> >>>> collimation it seems to be almost perfect but as soon as I go
> >>>>
> > near
> >
> >>>> focus the star begins to look lik a doughnut. The perfect
> >>>>
> > circle
> >
> >>>>
> >>>>
> >>> is
> >>>
> >>>
> >>>> gone. Same thing happens if I reach a point near perfect
circle
> >>>>
> >>>>
> >>> and
> >>>
> >>>
> >>>> the star is not centered in the view, when centered it no
> >>>>
> > longer
> >
> >>>>
> >>>>
> >>> has
> >>>
> >>>
> >>>> the perfect circular form.
> >>>>
> >>>> The colliamting procedure is very easy to follow but still I
> >>>>
> > cant
> >
> >>>>
> >>>>
> >>> get
> >>>
> >>>
> >>>> it collimated.
> >>>> What is wrong ?
> >>>>
> >>>> Regards
> >>>> Timo Nordberg
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> ---------------------------------
> >>>> Moody friends. Drama queens. Your life? Nope! - their life,
> >>>>
> > your
> >
> >>>>
> >>>>
> >>> story.
> >>>
> >>>
> >>>>  Play Sims Stories at Yahoo! Games.
> >>>>
> >>>> [Non-text portions of this message have been removed]
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>> Yahoo! Groups Links
> >>>
> >>>
> >>>
> >>>
> >>>
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>

Hello,

I will be receiving delivery in a few days of my RCOS 16 inch (Ion
milled f/9, 3600 mm FL) scope. My second scope is a Takahashi FSQ
106N (f/5), equiped with a TakoMeter rotator.

My mount is a permanently mounted Paramount ME with a large TPoint
(potentially ProTrack) model.

The setup is remotely operated, using CCDAutoPilot.

I own 2 cameras:
- 1 STL 11000 M class 2
- 1 ST10 XME (with AO-7)

My site is very dark (one of the darkest in France) but the seeing is
only average 2" to 3" (1000 ft altitude).

I am mostly imaging LRGB with some Ha. I am (so far) guiding with the
on chip guiders (No off axis yet).

I am struggling with the pairing of my cameras and scope.

Option 1: ST10 on FSQ and STL on RCOS. I put the larger pixels (STL)
on the scope with the longer FL to get a better image scale on both
scopes

Option 2: ST10 on RCOS (with AO-7?) and STL on FSQ. I put more
sensitivity on the f/9 scope than on the f/5 scope.


Any recommandation / suggestion appreciated.

Emmanuel Schalit
Paris France

Given that you have a dark sky, your use of that STL 11000 depends on
what you want to do. It can work on either setup. However, with your
seeing at 2-3", I suspect that you would not really get good use out of
the ST-10 on the big scope (hugely oversampled).

The unique thing about low-QE cameras and dark skies is that they offer
an interesting advantage. Under dark skies, you have the opportunity to
take really long exposures because of the low sky background
contribution. What that really means is that the read noise of the
camera dominates; there is very little background shot noise. So you
might find that 30-, 60-, or even 90-minute exposures with the STL-11000
yield excellent deep sky results. Under my skies in New Mexico, I need
an estimated 93 minutes for shot noise to overcome read noise!

The advantage of the ABG STL-11000 is that stars will not bloom with
such long exposures. Granted, you might be able to nearly cut those
exposure times in half with the ST-10 - but you'd have blooms galore.
Thus, even though you need more time to gather photons with the
STL-11000, you can effectively go deeper because you need not worry
about excessive blooming.

Ron W

Emmanuel Schalit wrote:
> Hello,
>
> I will be receiving delivery in a few days of my RCOS 16 inch (Ion
> milled f/9, 3600 mm FL) scope. My second scope is a Takahashi FSQ
> 106N (f/5), equiped with a TakoMeter rotator.
>
> My mount is a permanently mounted Paramount ME with a large TPoint
> (potentially ProTrack) model.
>
> The setup is remotely operated, using CCDAutoPilot.
>
> I own 2 cameras:
> - 1 STL 11000 M class 2
> - 1 ST10 XME (with AO-7)
>
> My site is very dark (one of the darkest in France) but the seeing is
> only average 2" to 3" (1000 ft altitude).
>
> I am mostly imaging LRGB with some Ha. I am (so far) guiding with the
> on chip guiders (No off axis yet).
>
> I am struggling with the pairing of my cameras and scope.
>
> Option 1: ST10 on FSQ and STL on RCOS. I put the larger pixels (STL)
> on the scope with the longer FL to get a better image scale on both
> scopes
>
> Option 2: ST10 on RCOS (with AO-7?) and STL on FSQ. I put more
> sensitivity on the f/9 scope than on the f/5 scope.
>
>
> Any recommandation / suggestion appreciated.
>
> Emmanuel Schalit
> Paris France
>
>
>
>
> Yahoo! Groups Links
>
>
>
>

>Hello,
>
>I will be receiving delivery in a few days of my RCOS 16 inch (Ion
>milled f/9, 3600 mm FL) scope. My second scope is a Takahashi FSQ
>106N (f/5), equiped with a TakoMeter rotator.
>


A potential problem you may need to consider is how much of the large
STL 11000 CCD chip will be illuminated by the 3600 mm RCOS 16 inch
scope. RCOS systems should be better than a standard Meade, but the
physical size of the image circle is often the limiting factor.
Compare the image size of the telescope with the diagonal size of the
CCD array. This is a problem with many of the larger STL CCD arrays
and many commercial telescopes, but not a problem with many wide
field refractors and astrographs.
--
********************************
Dr.D.T. Durig
Departments of Physics and Chemistry
Director of The Cordell-Lorenz Observatory ( OBS CODE 850 )
The University Of The South
Sewanee TN 37383-1000
New area code !!! 931-598-1570
FAX 931-598-1145
ddurig@...
web page at
http://www.sewanee.edu/physics/OBSERVATORY/astronomy/WWW/default.html