The August 12, 2004 meeting of the Champaign-Urbana Astronomical Society 
was called to order at 7pm by President Jeff Byrant in the Staerkel 
Planetarium. 20 people attended the meeting.

Items discussed:

Almost everybody attending had watched for Perseid meteors. Dave Leake 
reported that he thought the peak was between 2 and 2:30am. The weather 
cooperated for once, and it was a pleasant night to watch the sky.

Next month we should be watching the DVD about cosmology.

Mike Lockwood announced that the 30 inch mirror figuring is complete, and 
it should be coated soon.

The treasurer Phil Wall recently had a class for those members who wish to 
get a dome key, and one of the two people attending the class now has a 
dome key. Phil plans on holding another class an hour or so before the next 
family sky watch August 21. Contact Phil if you plan to attend the class.

Calendars are here.

Dave Leake is getting calls from people who call the City of Champaign 
about light pollution.

The big issue of the evening was the dome telescope. At out last meeting, 
Bob Lozar took a poll of what the clubs "dark sky" site should be, and our 
dome won the designation as "our" dark site. I believe that this is what 
led to the firestorm of  cuas list emails, which were started with a post 
by Guy Hampel on July 13. Here is just a short part of that email, which 
was posted to the cuas mailing list:

Questions to be answered or at least discussed amongst ourselves.
        What is the value of the current telescopes?  Both money and quality.
        Is there hope for people to use the site every available dark night and 
what will it take?
        What is the long range plan for the club site and what will it take to get 
there?
        Will investing in more stuff (a technical term I think) generate more 
interest in the club?
        The list of questions is actually very long so the last one is, What is 
the purpose of the club?

The flood of emails came up with ideas of replacing the old club scope with 
a new GOTO-capable scope, keeping our current scope, but replacing our 
FrankenMount with a new mount costing from $10,000 to $15,000, to leaving 
it as is because we have limited resources, to ripping out the Cass and 
putting the new club Dob in the observatory, etc.

We need some perspective!

CUAS started in 1986. In six short years, our club mustered up the gumption 
to build itself an observatory. Really, a quite extraordinary 
accomplishment. The top, rotating dome and slit was recycled from the 
University of Illinois. Much of the materials and labor were donated by 
local businesses. The bottom part of our equatorial mount used to belong to 
a 30 inch telescope. The top part of the mount was built using angle iron 
and plywood. It was not meant to be permanent, and it has balance problems. 
The club started an "Observatory Fund" to raise the serious cash needed to 
complete the project. The club got a Slipher grant of $970 to pay for the 
primary mirror. A lot of people put in a lot of hard work, and it all came 
together in 1992. It is a part of our club, and we should be proud of it. 
But we should also to continue to improve the telescope as our capabilities 
and funds allow.

Our dome telescope just celebrated it's twelve anniversary in July. 
http://www.prairienet.org/cuas/observatory.shtml

The mirror was tested at Adler Planetarium's old optics shop. A fellow 
named Bill Buddington, made the mirrors. But it was tested with the 
original secondary mirror, which is not being used now.

At some point, when the telescope was being assembled, the original 
secondary mirror did not seem to do the job properly no matter how much the 
position of the secondary mirror was adjusted. At some point,  Aart Olsen 
volunteered that the club could borrow his secondary mirror, and that is 
the mirror in the club telescope since 1992.  You should note that 
secondary mirrors for Cassegrain telescopes are not really interchangeable; 
usually the primary and secondary mirror are supplied as a matched set.

It has been noted that the optics are not working very well. It could be 
that if the proper secondary could be obtained, we could get better optical 
performance from the dome's 16 inch telescope.

Scott Hough mentioned that one of the biggest shortcomings of the current 
mount is that the declination axis uses some rather crude bearing parts. 
Scott thinks that if the scope's mount were to be slightly rebuilt, that 
the declination axis could be made to work much more smoothly.

Scott thinks the optical tube assembly weighs about 80 - 100 pounds. He 
also thinks the refractor weighs about 40 pounds.

Mike Rosenberger mentioned that right ascension shaft turns with lots of 
torque, and that he looked into getting replacement bearings for the mount, 
and that they would be $600 when he checked back in the 90's. New bearings 
would probably cost more today.

Mr. Byers, who builds gear sets for driving telescopes for a living, said 
none of the gears he would sell could handle the kind of torque required to 
turn our mount in Right Ascension.

I tried in vain to build a suitable drive mechanism for RA, trying three 
different times. I have electronics, a motor and gearbox that have actually 
moved the telescope through almost 180 degrees of right ascension. Being 
only good working in wood, I cannot construct a sturdy enough fixture to 
attach the motor/gearbox onto the mount.

The bottom line is that the current dome scope could be improved in the 
following ways:

1. Test the optics. This would require taking the primary mirror out of the 
dome for a few days. Mike Lockwood has offered that he would test the 
mirror and could refigure the mirror. It would be helpful if we can find 
the old secondary mirror, too.

2. Rebuild the declination bearings. This could take some time, and the 
dome would be out of commission while the bearings are rebuilt or 
re-fabricated.

3. Refurbish the right ascension bearings. This would involve removing the 
homemade mount from the old 30 inch scope mount, and replacing the bearings.

4. Get a motor drive attached to the telescope. This needs someone who can 
work in metal.

Mike Lockwood pointed out that if the club finishes the 16 inch club Dob 
scope, that that would take some of the pressure off having a working dome 
scope, which means the first priority is to complete the new Dob scope. My 
guess is the new club Dob could be done by the end of September.

There was some consensus that the club should do the following:

1. Finish the 16 inch club dob.
2. Find the old secondary mirror for the Cassegrain scope.
3. Evaluate the Cass primary.
4. Wait for any changes to the OTA caused by new primary, new secondary, etc.
5. Rebuild/improve the mount, particularly the declination axis. Better 
balance also needs to be achieved.
6. Lastly, motorize the mount.

The meeting was adjourned at about 8:40PM.


Now, time for me to get on my soapbox. The CUAS 30th anniversary is coming 
up in less than two years. Why don't we try to get the dome refurbished, 
with better optical performance, with a drive running, by July, 2006?


Submitted by Bob Rubendunst
Secretary, CUAS