Hi All,

   I know of few of you may be thinking of coming to the
Star Party to set up telescopes for general public sky
viewing. Those of us from the staff usually put together
a potluck dinner for all those helping out, separate from
the refreshments for the general public. If you would like
to bring something to share you are more than welcome.
Please let me know what you plan to bring if you are
coming since I have been assigned as the potluck organizer.
If you are not going to the parade, then food will be set up
for eating at around 5pm Dec 5th, and after the parade for
those who are going to the parade. We will be there setting
up at 4pm but anyone with a telescope should be here before
the parade starts at 6pm. We will not be setting up a grill,
mostly it will be prepared dishes. We could use a green
salad, a pasta salad, or potato salad, another vege
casserole, corn bread, and a dessert.

So far staff will be bringing:

Small pot vege corn chili
Large pot meat based chili
Rice
Fruit/vege side

Thanks to all who are planning to help out!

Mahalo,
Lisa Wells
lwells@...

Andrew Cooper
----------------------------------------------------
http://www.darkerview.com

--- In whac@yahoogroups.com, "LarryO" <larryobrien@...> wrote:
>
> If you have two eyepieces of the same focal length but two different types or
manufacturers, will they have the same "sensitivity" to focusing? To put it
another way, since we'll always fall somewhere in front or back of perfect
focus, does the "fall away" from "as tack sharp as possible" depend solely on
the length, or are there other variables? To put it _another_ way, "Wow, is it
really this hard to focus at high magnification?"
>

One set of "limits" regarding the depth of focus are: the wavelength of light
you are viewing, the focal ratio of your optical system (squared), and the
quality of your optics. This includes such items as Barlow lenses, PowerMates,
and telextenders, if any. So any "softness" of the system is a function of the
optics feeding any eyepiece.

In general, the higher quality of your eyepiece and the higher your
magnification, the sharper your focus. This determines the overall quality of
your images; the sharper, the better, and sharper images are harder to focus.
Sharper images are more demanding on the quality of your focuser, and some
splendid focusers have both a coarse and a fine (vernier) focusing knob to
facilitate precision focusing.

As far as eyepieces go, the better the design and manufacture, the crisper the
image. Huygens, Ramsden, and Kellner designs are, in general, inferior and
unsuitable for many modern telescopes. Orthoscopic (Abbe), Plossl, and Panoptic,
while not really modern designs are well corrected and have reasonably wide
fields of view, suitable for all but the fastest modern telescopes.

Quality is paramount, and Clavé, TeleView, and Zeiss share very good
reputations. Comparing randomly selected Orion or Meade units of any given
design with the above mentioned manufacturers, often show the shortcomings of
inferior quality.

Sensitivity to focus is a desirable characteristic, and when used with a good
quality focuser  gives superior results. I would be pleased to send anyone a
useful article concerning the evolution of eyepieces upon request.

Friendly regards,

Stan Truitt  HAA Maui

For a given aperture size, the sensitivity to focus is entirely a
function of the focal ratio of the telescope and the magnification (as
controlled by the eyepiece). There are actually two regimes; one where
the magnification is sufficiently high that the eye can resolve the Airy
disk and the other is where the Airy disk is unresolved. Once the Airy
disk is easily resolved, the magnification (set by the eyepiece focal
length) has a less significant effect on the apparent sensitivity to focus.

The focal ratio of the telescope affects the focus sensitivity for the
same reason that the depth of field is greater when using the slow
f/stops on your camera. The rate at which the focus spot increases away
from the best focus (neglecting diffraction) is inversely proportional
to the f/ratio of the telescope. For example, an f/4 telescope is twice
as "touchy" in its focus (i.e. the focuser must be moved a shorter
distance) as an f/8 telescope of the same aperture to observe a
noticeable change in focus. Note that the the Airy disk subtends the
same angular size on the sky in both telescopes, however in the f/8
telescope the linear size of Airy disk is twice as large as in the f/4
telescope. It is also assumed that the focal length is maintained when
comparing both instruments, so a shorter focal length eyepiece must be
used in the faster telescope to keep all things equal.

The only difference between any reasonably good eyepiece model (most of
what is being sold today) is in the field curvature of the eyepiece and
how well this matches (or not) the field curvature of the telescope
being used. There are no hard and fast rules here and no manufacturer
quotes the field curvature of their eyepieces because generally this
does not matter (the eye can refocus a small amount as it scans the
field of view). This has no effect on focusing objects near the center
of the field of view.

So, in short, no, you should not notice a difference in focusing
sensitivity between two eyepieces of the same focal length. However, it
is harder to use an eyepiece with poor eye-relief or bad color
correction which could make good focusing more challenging, or even
impossible in the latter case. Also, it can be difficult to focus on an
extended object if the seeing is poor. Try focusing on a nearby star (if
you're observing Jupiter, use one of the moons) and come back to your
object of interest.

Cheers,

Marc

LarryO wrote:
>
> If you have two eyepieces of the same focal length but two different
> types or manufacturers, will they have the same "sensitivity" to
> focusing? To put it another way, since we'll always fall somewhere in
> front or back of perfect focus, does the "fall away" from "as tack
> sharp as possible" depend solely on the length, or are there other
> variables? To put it _another_ way, "Wow, is it really this hard to
> focus at high magnification?"
>
>

If you have two eyepieces of the same focal length but two different types or
manufacturers, will they have the same "sensitivity" to focusing? To put it
another way, since we'll always fall somewhere in front or back of perfect
focus, does the "fall away" from "as tack sharp as possible" depend solely on
the length, or are there other variables? To put it _another_ way, "Wow, is it
really this hard to focus at high magnification?"

My email account has been HACKED!

Send NO money to ANYONE!

I am just fine, sitting at home here in Hawaii.

More later as I work to figure and straighten this all out.

-Chris




--- In whac@yahoogroups.com, Christopher Erickson <christopher.k.erickson@...>
wrote:
>
> I'm sorry for this odd request because it might get to you too urgent but
> it's because of the situation of things right now, i'm stuck in Wales,
> United Kingdom right now. I came down here on vacation, i was robbed, worse
> of it is that bags, cash and cards and my cell phone was stolen at GUN
> POINT, it's such a crazy experience for me, i need help flying back home,
> the authorities are not being 100% supportive but the good thing is i  still
> have my passport but don't have enough money to get my flight ticket back
> home, please i need you to loan me some money, will refund you as  soon as
> i'm back home, i promise.
>
> --
> -Christopher Erickson
> Network Design Engineer
> 5432 E. Northern Lights Blvd., Suite 529
> Anchorage, AK  99508
> N61° 11.710'  W149° 46.723'
>

Yes, please bring your own scopes!

...forgot to mention that.

Marc

Christopher Erickson wrote:
>
>
> I would be interested!
>
> Can we bring our own scopes too?
>
> -Christopher Erickson
> Network Design Engineer
> Waikoloa Village, HI 96738
> N19°57' W155°47'
> Meade 16" LX200 SCT
> www.data-plumber.com
>

I would be interested!

Can we bring our own scopes too?

-Christopher Erickson
Network Design Engineer
Waikoloa Village, HI 96738
N19°57' W155°47'
Meade 16" LX200 SCT
www.data-plumber.com



> -----Original Message-----
> From: whac@yahoogroups.com [mailto:whac@yahoogroups.com] On
> Behalf Of Marc Baril
> Sent: Monday, November 23, 2009 9:05 AM
> To: whac@yahoogroups.com; Mary Beth Laychak
> Subject: [whac] CFHT winter star party
>
> The CFHT winter star party is coming up on December 5th from
> 7 to 10 pm (Saturday).  We usually set up some telescopes on
> the front lawn for public viewing and any volunteers from the
> WHAC are more than welcome to assist with this part of the
> event.  Let me know if you plan on coming so that I can let
> our organizer, Mary Beth, know how many people to expect.  We
> usually have a potluck around 5:00-6:00 pm that volunteers
> are invited to attend.
>
> Note that this is the day of the Waimea Christmas parade,
> which means that you should turn up well before 6:00 if you
> don't want to get caught behind the road block!
>
> Cheers,
>
> Marc
>
>
> ________________________________________________
>
> Hi,
>
> My calendar is telling me that the Winter Star Party is fast
> approaching.
> The date is December 5th from 7-10pm.  I'd like to have brief planning
> meeting, this Friday, Nov 13th at 2:30pm in the Large
> Conference room.
> I'm looking for volunteers in the following areas:
>
> Setup
> Telescopes- manning the scopes if it's actually clear
> Ask An Astronomer- astronomer to answer questions
> Remote Obs Room- someone to discuss observing/telescope
> Coffee/Cocoa- hand out coffee/cocoa/treats
> Calendar/Poster sales
> Robots- Tom B or Billy, let me know if you guys want to do this.
>
> We'll also have the keiki booth, I'll take care of that unless someone
> else wants to.  If you can't make the meeting, but are interested in
> helping out, please email me or stop by my office.  I'll be
> contacting the
> WHAC to let them know the date, we usually get a few of them
> to drop by
> with telescopes.
>
> Being that is this our 30th Anniversary, I'd like to make the
> Star Party
> this year something special.  Let me know if you have any suggestions!
>
> Thanks!
> Mary Beth
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

The CFHT winter star party is coming up on December 5th from 7 to 10 pm
(Saturday).  We usually set up some telescopes on the front lawn for public
viewing and any volunteers from the WHAC are more than welcome to assist with
this part of the event.  Let me know if you plan on coming so that I can let our
organizer, Mary Beth, know how many people to expect.  We usually have a potluck
around 5:00-6:00 pm that volunteers are invited to attend.

Note that this is the day of the Waimea Christmas parade, which means that you
should turn up well before 6:00 if you don't want to get caught behind the road
block!

Cheers,

Marc


________________________________________________

Hi,

My calendar is telling me that the Winter Star Party is fast approaching.
The date is December 5th from 7-10pm.  I'd like to have brief planning
meeting, this Friday, Nov 13th at 2:30pm in the Large Conference room.
I'm looking for volunteers in the following areas:

Setup
Telescopes- manning the scopes if it's actually clear
Ask An Astronomer- astronomer to answer questions
Remote Obs Room- someone to discuss observing/telescope
Coffee/Cocoa- hand out coffee/cocoa/treats
Calendar/Poster sales
Robots- Tom B or Billy, let me know if you guys want to do this.

We'll also have the keiki booth, I'll take care of that unless someone
else wants to.  If you can't make the meeting, but are interested in
helping out, please email me or stop by my office.  I'll be contacting the
WHAC to let them know the date, we usually get a few of them to drop by
with telescopes.

Being that is this our 30th Anniversary, I'd like to make the Star Party
this year something special.  Let me know if you have any suggestions!

Thanks!
Mary Beth

What does this really mean? Does it mean that the probability of life elsewhere
in the Universe is more likely?  Does this change anything or does it change
everything?

I am just curious what ya'll think.

Jeff and I are planning to go up there tomorrow because we cannot come on
Monday.  Is anyone planning to go up?