Jeff Moore of NASA Ames will describe these probe objectives and update the mission's progress in data collection.
As reported last month, the drive motor on the 17.5" telescope stripped an internal gear, making the drive system inoperative. The original motor was a 5-Watt Hurst model CA 1/2 RPM, used with a 2:1 gear reduction driving the worm. Three smaller surplus one RPM motors with a 4:1 gear reduction were tried, as was a smaller surplus 1/2 RPM motor with the original gears. None were strong enough to turn the telescope.
A new Hurst motor exactly like the original was then ordered, fresh from the factory in Indiana. It arrived on April 29, 1997, right before this newsletter went to print. I suspect that there still is a problem with the mount causing excessive friction between the worm wheel and the mount, which, with the existing slight unbalancing of the telescope, caused the original motor to fail. I want to investigate reducing some of this friction so that the load on the motor is less. But by the time you receive this, the new motor should be installed on the telescope, and the telescope drive system should be working once again. [Webmeister: It's in. It works.] The process of polar alignment can then begin.
The broken connectors on the spider vanes have been replaced. The cause of the failure is still somewhat of a mystery. In the future I think it would probably be a good policy to never expose the tube to direct sunlight for more than a few minutes or so at any one time. Installing some exterior insulation against radiant energy may prevent further problems, and may be a good idea anyway. I want to install interior insulation and baffling in the tube to improve the performance anyway.
While collimating the telescope with the fixed spider, I noticed that there was signigicant flex and/or slop in the eyepiece tube when a force of one or two pounds was applied (about the weight of the 13mm Nagler eyepiece normally used with that telescope). Since an f/4.5 Newtonian must be collimated to less than 0.5mm
to preserve a diffraction limited image, eliminating this flex is very important. I tightened up the friction drive and remounted the JMI Crayford-type focuser on the telescope tube, rotated 180 degrees in an orientation that should result in less flexture for most orientations of the telescope. This greatly reduced the flexture. However some flexture remains and it appears to be caused by bending in the aluminum tube itself where the focuser is mounted to the tube. The focuser is normally operated with two 2-inch extension tubes, producing quite a bit of torque when supporting a heavy eyepiece. Some steel re-enforcing (tube stiffeners) where the focuser is mounted to the aluminum tube should fix the remaining flex. I suspect that the amount of flex remaining right now is very signifi cantly less than what we had when the telescope was in its old cardboard tube.
On another subject, a flag will be installed on the (concrete filled? ) PVC pier to make it more visible to people who are backing up their vehicles nearby. If you use this pier, be sure to replace the flag when you are done.
parties at Sycamore Grove, Livermore. Put the dates June 7, July 5, August 2, and September 6 into your Daytimer, so you won't miss any of them.
Jim McIntire has secured five campsites at Camp Shelly for TVS members June 27-29. The club will present public star parties Friday and Saturday nights. Contact Jim at 209 /836-3836 to reserve your spot.
Our next The Dark Site open house is set for May 31 at 7 PM
Earl's place will be filled by Bill Burnap, who volunteered at the last general meeting. We welcome his help and look forward to his company at the monthly pizza party meetings.
ATM including mountings
photography Astrophoto equipment
Remote access to scope
Activities rated for their importance to members (1 = very important, 5 = no interest)
|Star parties at The Dark Site||9||9||5||3||1|
|Public star parties||5||3||6||4||1|
|Fi eld trips to Yosemite/White Mt.||8||4||2||8||2|
|Using 30" Scope at Fremont Peak||2||3||5||6||3|
|School programs/pr esentations||2||4||4||5||3|
|Computer programs, Internet, BBS||5||6||4||5||5 |
How did you learn about the club?
Web Site = 3
S&T = 2
Lumicon = 16
Neighbor/club member = 7
Other = 3
Why did you join the club?
Technical people & help = 14
Discounts = 1
Meet other amateurs = 6
Astrophoto = 1
Try different scopes = 1
Get away = 1
The Dark Site Site = 6
Meetings = 1
Yosemite/White Mt Trips = 2
ATM = 1
Are we meeting your expectations? Yes = 31 No = 0
How long have you been a TVS member?
<1yr = 7
1-3yrs = 8
3-5 yrs = 9
>5 yrs = 9
How long have you been interested in astronomy?
<1 yr= 1
1-3 yrs = 0
3-5 yrs = 2
5-10 yrs = 1
>10 yrs = 24
How often do you attend monthly meetings?
Almost always = 4
Half the time = 3
Occasionally = 13
Never = 11
How often do you go to The Dark Site?
Several times a month = 2
Once a month = 0
Every 2-3 months = 3
1-3 times a year = 12
Never = 13
Do you have a computer?
31 No =
Type? Macintosh = 8 IBM/Clone = 24
Do you have a modem? Yes = 28 No = 2
Have you ever logged on to the TVS BBS? Yes = 15 No = 16
Have you visited the TVS web page? Yes = 16 No = 15
Do you have access to the Internet? Yes = 26 No = 5
Do you have access to e-mail? Yes = 26 No = 2
Do you use the computer for astronomy-related purposes?
Yes = 21 No = 7
If so, what purposes
Star Charts = 10
General internet = 7
Image processing = 1
Learning software = 1
Data analysis = 1
Satellites = 1
Telescope design = 1
Sun = 1
Photos from NASA etc. = 1
Data to AAVSO = 1
Have you ever borrowed books from the TVS library? Yes = 11 No = 15
Books you would like to have? "old classi cs", Starlight Nights, ATM books, references.
Are you interested in helping with a school program? Yes = 6 No = 16
Newsletter and format: Good, Fine, OK.
Activities you would like us to provide? Spotting asteroids.
Suggested improvements to the club? Publish meeting notice in the newspaper.
|5||Mon||Cinco de Mayo (Battle of Puebla).|
|Ganymede occulted by Jupiter 3:05 AM|
|6||Tue||New Moon 1:46 PM|
|7||Wed||Galileo fourth flyby of Ganymede (1,5 84 km).|
|8||Thu||Aldebaran 0.6° south of Moon (occulted in Eastern U.S.).|
|Io eclipsed by Jupiter's shadow 3:12 AM|
|9||Fri||School star party in Tracy.|
|Islamic New Year 1418.|
|13||Mon||Beta Lyrae at minimum 3:40 AM Eclipsing binary drops from mag. 3.4 to 4.3 in about 3 days. (Period is currently 12.93 846 days. There is a secondary minimum of mag. 3.8.) Compare with Gamma Lyrae: mag. 3.24.|
|14||Wed||First Quarter Moon 3:55 AM|
|15||Thu||Space Shuttle Atlantis (STS-84) launch scheduled. (Mir docking mission.)|
|16||Fri||Tri-Valley Stargazers meeting 7:30 PM Unitarian Universalist Church in Livermore, 1893 N. Vasco Road, Livermore. (3/4 mile north of I-580).|
|Mars 2° north of Moon.|
|Io's shadow transits Jupiter 2:14 AM, followed by Io 3:34 AM|
|17||Sat||Star Party for Girl Scouts. Skyline Park, Napa.|
|Io reappears from occultation by Jupiter 3:12 AM|
|18||Sun||Venus 6° north of Aldebaran. Look shortly after sunset (8:13 PM).|
|19||Mon||TVS Planning Meeting 7:00 PM Round Table Pizza, 1540 First St., Livermore (in Orchard Supply/Longs/Safeway shopping center).|
|22||Thu||Full Moon 2:13 AM|
|Mercury at greatest western elongation (25 ° ) in morning sky.|
|23||Fri||Riverside Telescope Makers Conference begins. (Contact Fox & Stephens, 909-9 48-2205, for information.)|
|25||Sun||Pluto at opposition (mag 13.7).|
|Beta Lyrae at minimum 2:11 AM|
|27||Tue||Jupiter 4° south of Moon.|
|29||Thu||Last Quarter Moon 12:51 AM|
|30||Fri||Ganymede's shadow transits Jupiter until 3:17 AM|
|31||Sat||Open House at The Dark Site. Meet at the corner of Mines and Tesla Roads, Livermore, at 7:00 PM|
|Saturn 0.5° south of Moon (occulted in Africa and Asia).|
|Io eclipsed by Jupiter's shadow 3:21 AM|
|1||Sun||Io's shadow transits Jupiter until 2:47 AM; Io transit begins 1:46 AM PDT.|
|2||Mon||Io reappears from occultation by Jupiter 1:23 AM|
|5||Thu||New Moon 12:03 AM|
|Europa eclipsed by Jupiter's shadow 1:47 AM|
|Callisto occulted 3:08 AM|
|6||Fri||Venus 6° north of Moon. Look shortly after sunset (8:27 PM).|
|7||Sat||Star party at Sycamore Grove Park (Livermore Park District) 8:00 PM (Wetmore Rd. entrance near Holmes St.).|
|Excellent weekend for observing: No Moon after 10:30 PM|
|Europa transits Jupiter until 2:14 AM|
|Date (00UT)||R.A. (2000)||Dec||El||Sky||Mag|
|Date (00UT)||R.A. (2000)||Dec||El||Sky||Mag|
|Date (00UT)||R.A. (2000)||Dec||El||Sky||Mag|
Periodic Comet Tempel-Tuttle (= 55P = P/1997 E1) was recovered on March 4 by Karen Meech et al. using the Keck II 10-M reflector in Hawaii. This comet is responsible for the Leonid meteor shower which occurs every November. It should be visible in amateurs' scopes late this year, passing 0.36 AU from us early next year. By then it will be visible in binoculars in the northern polar region.
|Object :||Hale-Bopp||P/Wirtanen||P/Wild 2|
|Peri. Date:||1997 04 01.13453||1997 03 14.14299||1997 05 06.62789|
|Peri. Dist (AU):||0.9141030 AU||1.0637469 AU||1.5826156 AU|
|Arg/Peri (2000):||130.59083 deg.||356.34322 deg.||041.77000 deg.|
|Asc. Node (2000):||282.47069 deg.||082.20387 deg.||136.15458 deg.|
|Incl (2000):||089.42936 deg.||011.72255 deg.||003.24276 deg.|
|Orbital Period:||~2400 years||5.46 years||6.39 years|
|Ref:||MPC 28052||MPC 27080||MPC 28272|
|Epoch:||1997 03 13||1997 03 13||1997 04 22|
1. Number of times you have used the library in the last six months >5 4 3 2 1 0
Do you use the library's: (5=Frequently 0=Never)
Types of resources desired: (5=Strongly 0=Not at all)
|Specialty areas (other)||5||4||3||2||1||0|
|Books on tape||5||4||3||2||1||0|
4. Would an on-line catalog be useful to you? 5 4 3 2 1 0
5. Have you contacted the library web page? Y N
How valuable to you is the: (5=Very 0=Not at all)
|Interlibrary loan page||5||4||3||2||1||0|
7. Is the collection easy to search Y N
8. Do you have a CD ROM on your computer? Yb N
What is your interest in CD ROM images? 5 4 3 2 1 0
What is your interest in CD ROM programs? 5 4 3 2 1 0
Mail to Chris Cody, TVS Library, P.O. Box 142, Benecia, CA 945 10-0142; or bring to the next general meeting you attend.
Tri-Valley Stargazers Membership/Renewal Application
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