In order to determine possible cause of the lift and how to remove it all now so
that it can be reattached, you need to advise what you used to attach it
originally.

I use contact cement to attach laminate (standard for attaching laminate in most
situations involving laminate and wood - counter tops, etc.).  Depending on what
your altitude bearings are made of will determine ultimate method.  Assuming
plywood, apply one coat of contact cement to the bearings and let it dry
according to the directions, then apply a second coat.  When applying the second
coat to the bearings also apply a coat to the laminate.  After drying the
appropriate time, stick the laminate to the bearing and use a roller or clamp
jib to apply pressure and press the laminate onto the bearing.  This should last
a very long time.  (I use this method for my telescopes also when "laminating"
layers of wood together for furniture and cabinet making, etc.)

Tim Ulmer

--- In atm_free@yahoogroups.com, "davidfpitre" <davidfpitre@...> wrote:
>
>  Less than a year after attaching laminate to my 30" altitude bearings, it has
lifted up in the center....on both sides. Strange that it has separated in the
same place on both sides. It seems that it would have to have been pulled back
(from the end towards the center) in order to be raised in the center. Why would
it have lifted in the center?
>  I'm about to remove it and reattach it. Any advice on the procedure, or on
avoiding the same problem? The bearings are attached to the mirror box.
>  I'm undecided on contact cement vs 3M 77 aerosol.
>

Thanks for your response.
  My bearings are Ebony Star on plywood. The bearing surface of the plywood has
some coats of urethane, though I'm pretty sure I roughened the texture before
applying contact cement. I only did one coat of contact cement on both surfaces,
letting it dry about 30 minutes before pressing the surfaces together. I used
substantial pressure after contact (over 50 lbs/"), but the pressure was brief.
I did not try to clamp the 2 .

Would sanded urethane not be a be a good surface for contact cement?
I don't remember the grit sand paper.

David



--- In atm_free@yahoogroups.com, "tsulmer1" <timulmer@...> wrote:
>
> In order to determine possible cause of the lift and how to remove it all now
so that it can be reattached, you need to advise what you used to attach it
originally.
>
> I use contact cement to attach laminate (standard for attaching laminate in
most situations involving laminate and wood - counter tops, etc.).  Depending on
what your altitude bearings are made of will determine ultimate method. 
Assuming plywood, apply one coat of contact cement to the bearings and let it
dry according to the directions, then apply a second coat.  When applying the
second coat to the bearings also apply a coat to the laminate.  After drying the
appropriate time, stick the laminate to the bearing and use a roller or clamp
jib to apply pressure and press the laminate onto the bearing.  This should last
a very long time.  (I use this method for my telescopes also when "laminating"
layers of wood together for furniture and cabinet making, etc.)
>
> Tim Ulmer
>
> --- In atm_free@yahoogroups.com, "davidfpitre" <davidfpitre@> wrote:
> >
> >  Less than a year after attaching laminate to my 30" altitude bearings, it
has lifted up in the center....on both sides. Strange that it has separated in
the same place on both sides. It seems that it would have to have been pulled
back (from the end towards the center) in order to be raised in the center. Why
would it have lifted in the center?
> >  I'm about to remove it and reattach it. Any advice on the procedure, or on
avoiding the same problem? The bearings are attached to the mirror box.
> >  I'm undecided on contact cement vs 3M 77 aerosol.
> >
>

Just a few tips,
1  clean the surfaces with lacker thinner before coating with C.C.
2  Drill smal screw hole in each end of the laminate to screw it down whe
installed (it takes only a mm move to make a bubble and the screw can be a stop)
3 Low humidity helps in drying, place 2 coats on the wood let dry between coats
4 place 1 screw as soon as possible, before the whole strip is in touch, it is a
thrirt hand,
5 PRESS/ROLL the laminate in place,use a wood block and hammer, place the second
screw.
6 use good mylar bearings.
Peter


--- In atm_free@yahoogroups.com, "davidfpitre" <davidfpitre@...> wrote:
>
>  Less than a year after attaching laminate to my 30" altitude bearings, it has
lifted up in the center....on both sides. Strange that it has separated in the
same place on both sides. It seems that it would have to have been pulled back
(from the end towards the center) in order to be raised in the center. Why would
it have lifted in the center?
>  I'm about to remove it and reattach it. Any advice on the procedure, or on
avoiding the same problem? The bearings are attached to the mirror box.
>  I'm undecided on contact cement vs 3M 77 aerosol.
>

Actually, the "working" depends on the type of contact cement used.  I use the
water based Lepages contact cement which has a working time of 60 minutes.  At
70 Deg F it takes about 30 minutes to dry.  Then you have 30 more minutes to
assemble the parts.  To tell if it is dry, watch for it to change colour from
milky to clear and shiny and it should NOT be sticky to the touch.  A good way
to test is to put a piece of paper on it and see if it is tacky - the paper
should come off without resistance.  Anyway, none of this this overly critical. 
If using water based, wait a good 30-40 minutes then assemble.

Tim


> 30 minutes is way too long for contact cement to dry. You need to assemble
> the 2 pieces as soon as the cement is no longer tacky. It depends upon the
> temp but I'd say 15 minutes at the most.
>
>

Just in case anybody is interested. I resolved the micro-slippage issue:
- Partly resolved by changing out the nylon wheels by  aluminum ones [advise
from Peter de Baan]
- Rest of the trick did working on the balance [advise from Mel and Jan] a wee
bit more, down-side is that the balance needs to be very accurate, even the
difference between the weights of different oculairs is noticable. Not perfect,
but a workable solution.

Bottom-line: one my next scope I'll use a HDT or other sort of timingbelt, and
NEVER a flat belt anymore....

--- In atm_free@yahoogroups.com, "Martin" <matersmartin@...> wrote:
>
> Indeed, and I'm the guy who build it. Last issue I'm trying to resolve, as
both Jan and Mel will know, is some micro-slippage in the Altitude bearing
[small nylon wheels and hard-rubber on the sectors]. Any advise is more then
welcome.
>
> Martin
> --- In atm_free@yahoogroups.com, "Jan van Gastel" <jhm.vangastel@> wrote:
> >
> > It is a 12" f/5.3,  with Mel's stepper motor drive system.
> > I know the person who built the scope (and the scope).
> >
> > Jan
> > http://members.ziggo.nl/jhm.vangastel/Astronomy/
> >
> >
> >   ----- Original Message -----
> >   From: trulyyours05
> >   To: atm_free@yahoogroups.com
> >   Sent: Wednesday, November 11, 2009 8:23
> >   Subject: [atm_free] Re: a new scope comes on line
> >
> >
> >
> >   Ah-ha. Let me guess... 18-20" at a little over f4.5??? Nice. Someone is
having fun.
> >
> >   Al
> >
>

How does one order the book?

Rob

--- In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...>
wrote:
>
> I think that what Thomas proposed is closest to be efficient. Buying the book
> is unfortunately not, because David sold the rights to publisher and will get
> practically nothing. David told me that when  I ordered the book.
> I  think that Richard (S) who cared most for David in "real time" and with
real actions,
> can suggest what kind of help we can do to be practical and efficient.
> I am in, and will accept his proposals fullhartedly.
>
> Regards
> Vladimir.
>

Maroof called me for directions around Asar time. He was near Noor Jehan /
Jehangir Tomb. I couldn't help much as I was not familiar with that area.
He asked locals and managed to reach the school well in time.
I set off when it was dark. The first thing which I noticed was the big
traffic jam at the Ravi bridge. The bridge should be 3 times wider.
After the bridge, I asked a pedestrian about directions to Jehangir's
Tomb. He explained but it was confusing. It seemed he was telling me to go
against the traffic coming from the opposite direction. I continued, not
clear about his directions. Soon I saw a big road crossing. I asked again
and was told to move to the extreme right lane, to go against the onslaught
of traffic. How odd. I made it safely to the lane. Asked for directions
again.
Saw a well lit and lively place. Asked a sitting cyclist about the Tomb
and he gave fresh directions. The well lit place was Noor Jehan's Tomb.
Jehangir's tomb was totally without lights. Stark contrast to Noor Jehan's
Tomb.
Little further I saw railway lines. Turned left. On my left was a deep
area, flooded with water. Turned left again and found myself on a broad,
well constructed, straight, well lit road. Tall sodium light poles on the
left placed at regular intervals going straight ahead towards the vanishing
point. I asked a pedestrian again about the school. He guided very well. I
offered to give him a ride but he politely refused. He had a good kilometer
ahead to walk and he preferred walking. That felt odd. The road was so high
from the surrounding plains that the tree top canopies just reached the
road level. Was this road also acting like a flood barrier? Perhaps.
Soon saw a big two storied school building on my left with rows of
classes. The area on the right was totally deserted. The air was suddenly
much cleaner and fresher. Lahore gets most of its fresh air from the west
and Shahdara gets it first, pristine, unpolluted, rich with oxygen, free of
dust, co2 and exhaust gases. I thought that the people of this place were
lucky to have this air all year. No wonder the school students did well in
their studies.
While I was slowly searching for the school gate, a lady sitting by the
roadside told me to continue and that I was on the right path. Talked with
Maroof sahib and told him about a gate from which many girls were emerging.
Parked my motorbike. As my steering and ignition locks had been badly
picked by neighboring boys, I was afraid that someone would steal my bike.
They could be open with even a screw driver. As only I knew about the
locks, I left it parked there unattended. With some effort entered this
flooded gate. Soon I saw the gathering and the multi media screen of
Khwarzimic. Many girls were gathered around the screen. Found Maroof Sahib,
Umair, Sabeh, Wasif, Naseer Khan from Afghanistan and rest of the
Khwarzimic team, all familiar faces. 14" Celestron inch was being
assembled. A tiny reflector, about 5 inch diameter, was also there on its
short tripod. I learned that it was recently donated to Khwarzimic by some
philanthropist. It was short in height and I thought I would have to kneel
to reach the eyepiece.
I went to Maroof Sahib. His 5 inch was a little distance further ahead on
the lawn. A group of girls had gathered around him. In a long line they
were looking at the Moon one by one and asking questions and Maroof sahib
was answering questions. This eyepiece was at the proper height. I left
this group undisturbed and went to see what was happening near the screen.
Due to unadjusted counterweights, the 14" was out of balance and so its
motors were unable to take it to the Moon. As soon as Umair restored
balance, the scope moved as he willed. Magnified Moon was on the screen.
Marias, hills, shadows, craters of all sizes, streaks etc. Umair explained
various crater shapes and formations, and groups of tiny craters within
larger craters. The students were very well behaved, their teachers were
around, and there were questions and also a small poetry session.
A few times I looked over my shoulder to see how Maroof was doing and each
time I found him looking at me. Wow! What remote control effect he had.
Later, near pack up time, I went to him and he said he felt tired standing
and talking all the time and would have liked some help from me to answer
the questions while he sat and rested.
The teachers and organizers took us inside a hall and treated us all with
tea and snack boxes. We chatted and sipped tea. Was it pink tea? Cant say
for sure. The atmosphere was cheerful, lively and we enjoyed the food.
While outside, Maroof Sahib showed us his little lap top which was called
atom or something. Umair asked us names of stars. There was some confusion
whether Deneb was the beak of the swan or the tail. Maroof said tail. He
showed it on his laptop. Umair asked me the name of a bright star and I
couldn't answer. After some more chatting, we were all on our way back. My
bike was still there, untouched.
A very enjoyable experience in all.




--------------------------------------------------------------------
mail2web.com – Enhanced email for the mobile individual based on Microsoft®
Exchange - http://link.mail2web.com/Personal/EnhancedEmail

 

Maroof called me for directions around Asar time. He was near Noor Jehan /
Jehangir Tomb. I couldn't help much as I was not familiar with that area.
He asked locals and managed to reach the school well in time.
I set off when it was dark. The first thing which I noticed was the big
traffic jam at the Ravi bridge. The bridge should be 3 times wider.
After the bridge, I asked a pedestrian about directions to Jehangir's
Tomb. He explained but it was confusing. It seemed he was telling me to go
against the traffic coming from the opposite direction. I continued, not
clear about his directions. Soon I saw a big road crossing. I asked again
and was told to move to the extreme right lane, to go against the onslaught
of traffic. How odd. I made it safely to the lane. Asked for directions
again.

contd...

Thanks Vladimir..I'll check that out.  maybe William-Bell sells it.

Rob

--- In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...>
wrote:
>
> Hi Rob,
>
> >How does one order the book?
>
> I have got mine via Amazon.
>
> UNDERSTANDING  FOUCAULT
> Harbour, David A.   Paperback
> (++P-1-J15D28**)  1934916013          (Do not know what the numbers are for,
>                                                                 probably
unimportant for order.)
>
> Price  $9.95
> Shipping & Handling  $3.99
>
> Book was ordered with Amazon in USA and shipped to USA address.
> Shipment & Handling fee can vary in other countries.
>
> Best regards
> Vladimir.
>

Good morning!

I am sad to report that I have had to remove Mr. N, without comment, from being
a member of the ATM_FREE GROUP. If you have not seen his message yet, consider
yourself blessed. I also had to remove several follow-up messages (but not the
posters) that were in reply to his due to the repeated offensive language and
content in their reply.

Please use some common sense here. If a message contains something that should
not be seen by your granddaughter, please don't re-post it in a reply. Sure, you
can hold the guys feet to the fire but don't be guilty of his transgression as
you do so! Mr. N. was removed from the GROUP for the language and contents of
his posting, I don't want to lose more members simply because they repeat or
repost offensive language or content... Read this as a gentle WARNING!

ATM_FREE is for the most part self moderated. Richard and Thomas do a really
fine job in keeping the post areas clean and roughly on topic without sensorship
by screening the Member's first posts. That's how it should be but, you guys,
the ATM_FREE users, can help a lot by not re-posting offensive messages...

I have not looked at the FILES or PHOTO areas for quite a while, perhaps
something has been posted there that is inappropriate as well. If any ATM_FREE
members run into something that is out-of-place, let the Moderators know by
posting to them directly and we will take care of it as soon as we are made
aware.

Please go back to the ATM_FREE Main Page and re-read the rules, they are simple
and sufficient for the purposes of this GROUP.

In the USA we are about to celebrate our THANKSGIVING Holiday, it marks the
passage of the first hard year of work by the original European settlers to N.
America and the celebration of their first harvest in time to ensure their
survival through the upcoming Winter. I hope that you all have a good holiday
season where ever you are.

I especially extend my best wishes and hope for cooperation between the ATM_FREE
members, no matter what race or religeon, as we all try to understand the
meaning and wonders of this universe we share together.

Ken Hunter
Owner ATM_FREE

Hi Ken,
Apologies for repeating the message and well done in removing the
transgressor.
Chris

Ken wrote:
>
>
> Good morning!
>
> I am sad to report that I have had to remove Mr. N, without comment,
> from being a member of the ATM_FREE GROUP. If you have not seen his
> message yet, consider yourself blessed. I also had to remove several
> follow-up messages (but not the posters) that were in reply to his due
> to the repeated offensive language and content in their reply.
>
>

Ken wrote:
> In the USA we are about to celebrate our THANKSGIVING Holiday, it marks the
passage of the first hard year of work by the original European settlers to N.
America and the celebration of their first harvest in time to ensure their
survival through the upcoming Winter. I hope that you all have a good holiday
season where ever you are.
>
I just re-remembered why I modeled my group after this one.
Thank you again, Ken.

Thanks Ken and congratulations on your diligence, decisiveness and your tone.
This is a great group and that is due to the owner, moderators and members.
Thank you all.

Al

--- In atm_free@yahoogroups.com, "Ken" <atm_ken_hunter@...> wrote:
>
> Good morning!
>
> I am sad to report that I have had to remove Mr. N, without comment, from
being a member of the ATM_FREE GROUP. If you have not seen his message yet,
consider yourself blessed. I also had to remove several follow-up messages (but
not the posters) that were in reply to his due to the repeated offensive
language and content in their reply.
>
> Please use some common sense here. If a message contains something that should
not be seen by your granddaughter, please don't re-post it in a reply. Sure, you
can hold the guys feet to the fire but don't be guilty of his transgression as
you do so! Mr. N. was removed from the GROUP for the language and contents of
his posting, I don't want to lose more members simply because they repeat or
repost offensive language or content... Read this as a gentle WARNING!
>
> ATM_FREE is for the most part self moderated. Richard and Thomas do a really
fine job in keeping the post areas clean and roughly on topic without sensorship
by screening the Member's first posts. That's how it should be but, you guys,
the ATM_FREE users, can help a lot by not re-posting offensive messages...
>
> I have not looked at the FILES or PHOTO areas for quite a while, perhaps
something has been posted there that is inappropriate as well. If any ATM_FREE
members run into something that is out-of-place, let the Moderators know by
posting to them directly and we will take care of it as soon as we are made
aware.
>
> Please go back to the ATM_FREE Main Page and re-read the rules, they are
simple and sufficient for the purposes of this GROUP.
>
> In the USA we are about to celebrate our THANKSGIVING Holiday, it marks the
passage of the first hard year of work by the original European settlers to N.
America and the celebration of their first harvest in time to ensure their
survival through the upcoming Winter. I hope that you all have a good holiday
season where ever you are.
>
> I especially extend my best wishes and hope for cooperation between the
ATM_FREE members, no matter what race or religeon, as we all try to understand
the meaning and wonders of this universe we share together.
>
> Ken Hunter
> Owner ATM_FREE
>

I have a Spherometer and i have no clue how to use it.  I used one in my  mirror
class but this one i bought is a little different is has a round base instead of
a straight bar.

It has been a few years since i made my last mirror so i know i forgot how to
use any of them. can some one please guide to some info for the newbee on how to
set up and use this spherometer.. there were no instructions just pages of
numbers

texereau says W stroke, stellafane says COC stroke, what do you guys use to get
the edges to polish out? any tips?

Ali,

I too have enjoyed your stories of astronomy in the Lahore region. For the first
one you posted I got on Google Earth and followed your journey. I now have some
idea of the layout of the land there. (Isn't there a impact site in northern
Pakistan?)

I believe the more we learn about each other the better the world will become.
It's nice to know that someone in Pakistan (you!) is doing public astronomy just
as I am doing here in northern Wisconsin. Different places, different cultures,
but a common goal. Keep it up!

Thank you Ken and I whish all a good Thanksgiving also
Peter

--- In atm_free@yahoogroups.com, "Ken" <atm_ken_hunter@...> wrote:
>
> Good morning!
>
> I am sad to report that I have had to remove Mr. N, without comment, from
being a member of the ATM_FREE GROUP. If you have not seen his message yet,
consider yourself blessed. I also had to remove several follow-up messages (but
not the posters) that were in reply to his due to the repeated offensive
language and content in their reply.
>
> Please use some common sense here. If a message contains something that should
not be seen by your granddaughter, please don't re-post it in a reply. Sure, you
can hold the guys feet to the fire but don't be guilty of his transgression as
you do so! Mr. N. was removed from the GROUP for the language and contents of
his posting, I don't want to lose more members simply because they repeat or
repost offensive language or content... Read this as a gentle WARNING!
>
> ATM_FREE is for the most part self moderated. Richard and Thomas do a really
fine job in keeping the post areas clean and roughly on topic without sensorship
by screening the Member's first posts. That's how it should be but, you guys,
the ATM_FREE users, can help a lot by not re-posting offensive messages...
>
> I have not looked at the FILES or PHOTO areas for quite a while, perhaps
something has been posted there that is inappropriate as well. If any ATM_FREE
members run into something that is out-of-place, let the Moderators know by
posting to them directly and we will take care of it as soon as we are made
aware.
>
> Please go back to the ATM_FREE Main Page and re-read the rules, they are
simple and sufficient for the purposes of this GROUP.
>
> In the USA we are about to celebrate our THANKSGIVING Holiday, it marks the
passage of the first hard year of work by the original European settlers to N.
America and the celebration of their first harvest in time to ensure their
survival through the upcoming Winter. I hope that you all have a good holiday
season where ever you are.
>
> I especially extend my best wishes and hope for cooperation between the
ATM_FREE members, no matter what race or religeon, as we all try to understand
the meaning and wonders of this universe we share together.
>
> Ken Hunter
> Owner ATM_FREE
>

Hi Louis
          We use a spherommeter to find out the "sagitta" curvature of the
mirror, we are "hoggen"rough grinding, first we need a good flat test surface.
You can make one by grinding two pieces of 1/4 or thicker glass cut from a
single piece of plate glass about 5" round or square fine grind the pieces
toghetter with 25 micron and strokes of 1" overhang untill both pieces are dull,
it will take likely no more than 10 minutes.
To use the spherometer place it on one piece of glass and turn the dial to
zero.than place it on the other piece and check whether it reads zero there
also, if not, go back to grinding with both pieces reversed (it was "mirror on
top" now tool on top, grind and test, you got it ready for use on your mirror.
If the diameter of your spherometer is 4" You can calculate the sagitta by
dividing 1/focal length (Fl 48")=1/48 equals 0.0208333".
You use the S.M.by placing it on many places on the surface of the mirror as
long as the center point is on the mirror surface. When it reads the same all
over to the proper number, you are ready for finer grinding

Good grinding

Peter


--- In atm_free@yahoogroups.com, "Louis" <faintfuzzies1@...> wrote:
>
> I have a Spherometer and i have no clue how to use it.  I used one in my 
mirror class but this one i bought is a little different is has a round base
instead of a straight bar.
>
> It has been a few years since i made my last mirror so i know i forgot how to
use any of them. can some one please guide to some info for the newbee on how to
set up and use this spherometer.. there were no instructions just pages of
numbers
>

Hi Greg,
         It is very common that the edge laggs in polishing, I use a circular
stroke whereby the pitch-lap tool(if same size as the mirror) is on the bottom
and mirror on top stroking with+/-1/4 to1/6th overhang all around while leaving
the lap alone and turning the mirror slightly by every turn with little extra
weigth on the mirror and sufficient liquit on the lap(it is the chemical working
of the co2 what does the work) by circular stroke grinding and polishing you get
more easely a good sphere and no "around the barrel"

Good Polishing
Peter

--- In atm_free@yahoogroups.com, "Greg" <gjowen2255@...> wrote:
>
> texereau says W stroke, stellafane says COC stroke, what do you guys use to
get the edges to polish out? any tips?
>

To add a bit :
If it has a round base with a sharp edge that touches the mirror surface, it is
a ring spherometer.

It has capability to measure radius of curvature at the edges far more than the
three leg/ball spherometer. For a ring Sphero, measure the radius (r) of the
ring
Measure the least count (l.c)of the dial indicator (value of the least amount (1
division)the indicator stylus travels that can be measured). To make meaning out
of tables of numbers apply the following formula
R=(d^2+r^2)/(2*d)
where
R = radius of curvature of mirror= twice focal length
d= depth to which the stylus of indicator travels below the reference ring edge
(taking care of l.c)
r= radius of ring
^= raised to the power symbol

If more help is required post r, l.c, photos of sphero base & pages of numbers.

Deepak


--- In atm_free@yahoogroups.com, "pdebaan" <pdebaan@...> wrote:
>
> Hi Louis
>          We use a spherommeter to find out the "sagitta" curvature of the
mirror, we are "hoggen"rough grinding, first we need a good flat test surface.
> You can make one by grinding two pieces of 1/4 or thicker glass cut from a
single piece of plate glass about 5" round or square fine grind the pieces
toghetter with 25 micron and strokes of 1" overhang untill both pieces are dull,
it will take likely no more than 10 minutes.
> To use the spherometer place it on one piece of glass and turn the dial to
zero.than place it on the other piece and check whether it reads zero there
also, if not, go back to grinding with both pieces reversed (it was "mirror on
top" now tool on top, grind and test, you got it ready for use on your mirror.
> If the diameter of your spherometer is 4" You can calculate the sagitta by
dividing 1/focal length (Fl 48")=1/48 equals 0.0208333".
> You use the S.M.by placing it on many places on the surface of the mirror as
long as the center point is on the mirror surface. When it reads the same all
over to the proper number, you are ready for finer grinding
>
> Good grinding
>
> Peter
>
>
> --- In atm_free@yahoogroups.com, "Louis" <faintfuzzies1@> wrote:
> >
> > I have a Spherometer and i have no clue how to use it.  I used one in my 
mirror class but this one i bought is a little different is has a round base
instead of a straight bar.
> >
> > It has been a few years since i made my last mirror so i know i forgot how
to use any of them. can some one please guide to some info for the newbee on how
to set up and use this spherometer.. there were no instructions just pages of
numbers
> >
>