Auburn Astronomical Society E-Newsletter
November, 2000

In this Issue

November Events  Coming in December… Magazine Subscriptions
CCSSC Telescope Clinic DSRSG 2000   PSSG 2001
Member News  Apodizing Mask  Leonids 2000
November Events

This month's meeting will be on Friday, November 3 at 8:00 PM, in room 215 of the Aerospace Engineering building, on the campus of Auburn University. Anyone from the Montgomery area wishing to car-pool, should meet at my house (518 Seminole Dr., Montgomery). We'll head for Auburn at 7:00PM. 

Our New Moon weekend falls on November 23, the Saturday after Thanksgiving. If you're not too full of left-over turkey sandwiches and if you've OD'd on football games, we'll have a star party to cleanse the soul. Location T.B.A.

Coming in December…

Dec. 1 Monthly Meeting -- Larry Lee speaking on The Origins Of The Space Shuttle
Dec. 4 Star Party at Thomas Head Elementary School in Montgomery
Dec. 7 Star Party at Opelika Middle School
Dec. 25 Partial Solar Eclipse (40%)

Discount Magazine Subscriptions

Sky & Telescope magazine and Astronomy magazine club subscriptions will be due this month.

SKY & Telescope magazine will cost $ 29.95 (regular $ 39.95). We will need at least 5 subscriptions to qualify. SKY Publishing also gives a 10% discount on books and products to those in Club Plan.

Astronomy magazine will cost $ 29.00 (regular $ 39.95). Kalmbach Publishing Company gives discount on their list of Kalmbach books:
1-4 books 33 1/3% off
5-9 books 35% off
10+ books 40% off
We will need at least 5 subscriptions to qualify.

You may bring your checks made payable to "Auburn Astronomical Society", to the November meeting or mail them to:

John Zachry
Treasurer, Auburn Astronomical Society
501 Summerfield Road
West Point GA 31833

If you have any questions, e-mail John at:

CCSSC Telescope Clinic
Dr. Shawn T. Cruzen

My name is Shawn Cruzen, and I am the director of the observatory at the Coca-Cola Space Science Center in Columbus. First of all, I'd like to thank you for adding me to your Astrofiles newsletter. Even though I have not been able to break free and join you on any observing sessions, I have enjoyed keeping up with the events of your group. It sounds like you have an active society with a lot of nice events.

Secondly, I'm writing you to let you know about an event that we have coming up, and to see if anyone from your group might want to participate. Our event is called "So You Want To Buy A Telescope," scheduled for Sat. Nov. 4th (3:30 PM EST). It will be an informational workshop for those interested in buying telescopes at Christmas time. Discovery Telescopes is sponsoring the event and has donated an 8-inch Dob to be given away as a door prize. We anticipate a pretty good crowd. I thought it might be a good opportunity to promote your society. We could provide you a table and you could give out information (?), or whatever you'd like to do. Also after the workshop, we'll be having an observatory open-house, which (if y'all brought your 'scopes) you could join in on, as well. I've also invited the Atlanta group to come down. (Believe it or not, we don't seem to have an active club in town!) Anyway, if you're interested in participating, we'd love to have you. Even if you just want to direct some would-be telescope buyers this way, that would be great, too.

As a note about future events, we're working on getting the Astronomy editor for the journal Nature (U.S. office in D.C.) down for a talk in January. He's a friend of mine, and we're just trying to work out the travel details now. If this comes about, I'll send you a note, in case you want to pass it on to your members.

Thanks for your time!
Clear Skies,

A $2.00 entrance fee allows you to see the Omnisphere Show "More Than Meets the Eye", attend talks and demonstrations on basic astronomy, astrophotography & telescope operations. Entrance fee will qualify you to win an 8" Dobsonian Telescope donated by Discovery Telescopes. Continue the evening for the monthly "Evening of Astronomy" Program with Dr. Shawn Cruzen beginning at 7:30 PM.

Deep South Regional Star Gaze 2000

As is typical for late October, the foliage along the way to McComb Mississippi and back was at its colorful peak. Hazy skies most of the way over there Wednesday gave little incentive to keep going but, as I've come to learn, weather is almost always unpredictable. The sky had cleared to a deep azure somewhere between Jackson and McComb. When I arrived at the observing field at 2:30 PM. I found the field nearly full of telescopes. So much so, that I elected to set up on the western edge of the field -- across the way from our traditional spot near the Mobile and Jackson clubs on the eastern side. Because of a prior commitment, I had to limit my stay this year to just Wednesday and Thursday nights. But, what glorious nights they were! Both nights were spent on an eclectic mix of old favorites and deep-sky challenges. The solar system was well represented with Uranus and Neptune early in the evening, followed by Saturn and Jupiter (in wonderful detail) a bit later. Wednesday night I swapped eyepieces and filters with Greg Thompson of the Mobile Astronomical Society, as he put his recently completed home-built 16-inch Dob (Gregg won 1st place in the home-made telescope competition) through its paces. Thursday was another gorgeous day -- shirt-sleeve temperatures during the day followed by sweat-shirt temperatures at night. Around midday, our old observing buddy, Rod Mollise, arrived for our annual reunion. Late Thursday afternoon, we adjourned en masse to "Mr. Whiskers" for catfish supper. Thursday night I filled in my observing gaps from the previous night until just after midnight. 

The only other delegate from AAS was Robert Rock, who didn't arrive until after I left. Reports I've read said that the seeing was at its best Friday night showing incredible detail on the gas giants. There was an incredible diversity of telescopes types -- no two quite the same.  A virtual smorgasbord of hardware and expertise to draw on is to be had there. For those of you who have been before, you know what I mean. If you've never been -- well, I think you'd really enjoy it. DSRSG 2001 will be from October 17 to October 21. Keep up with all that's happening at at DSRSG at

PSSG 2001 Moved to September
Ken Poshedly

After suffering through every spring trying to keep it away from Easter, close to the New Moon weekend and not too cold and not too warm, I polled all of you who went to the event with an on-line questionnaire last summer asking about having the event in the spring, September or October. With only one or two exceptions, the answer was for the New Moon weekend in September. Thus, it will be Thursday-Sunday, September 13-16, 2001. The featured guest will be Wil Tirion. 

Member News

We've received quite a few e-mail address changes:

Welcome to our newest member, John Woodall jwoo200@aol.comof Montgomery. Also, please join me in welcoming to the mail list, Richard Takacs of Pike Rd. AL . Richard writes: "I am a retired military pilot and attended the Air Force Academy. Currently I fly for Delta Airlines, which is why I could not attend the star party as I was called out for a flight."
Richard has done some astrophotography in the past and is telescope shopping now. We look forward to having Richard at the meetings and star parties.

Rod Havens writes that he is recovering from oral surgery and looking forward to our next star party. Here's to a rapid recovery, Rod.

The Apodizing Mask
Lacy Thomas

I thought this might be something of interest to the group.  The topic (Apodizing Mask) came up recently within the StarMaster users group - some folks thought it was some sort of illegal hippie-era device!!


Think of it as a "colander" (the screen kind, not the perforated metal kind), that fits over the end of a scope.  Various books explain how to make one.  They are generally used for planetary observing and they appear to clean up the view a bit.
(contributed by Mitch G.,, of the StarMaster (SM) user group; 
Debbie Schermerhorn's site has an article about a "do it yourself" apodizong mask by Ken Florentino:   complete with instructions to build your very own mask.
BTW, the proper name for an apodizing mask is a "Lyot Stop".
(contributed by Nick Taylor,, of the SM User Group.
The masks are great for Jupiter, Saturn, Venus and Mercury.  They kill off glare and give better contrast, especially on the details of Jupiter.  Also good for some double stars.  We call it the "60's mask" because it also causes psychedelic colored light rays all around the object you are viewing.  They are easy to make and will fit right on the front of your scope with Velcro.
(contributed by Ginger Mayfield,, of the SM Users group.
Apodizing=eliminating some of the results caused in the focal plane from diffraction within the scope.  The Lyot stop screen is evidently intended to remove from the focal plane some of the diffraction caused to the incoming light at the tube rim and periphery of the primary optical element; thus the graded density of the screen, increasing toward the outer edge of the light path into the scope.  Works well on planets as they have finite image size, not point light sources.  however, the Lyot screen allows all the light diffracted at the secondary to enter the focal plane.

The Hubble Space scope also has an "apodizer", but it is in/near the focal plane of the primary, and is intended to remove light diffraction being caused by the central obstruction and support 'arms' (secondary and spider supports).  The Hubble apodizer can be switched in/out of use.  In effect, it "shadows" from the focal plane, light which has passed the periphery of the central obstruction elements within the light path of the primary mirror as it looks back up and out of the main "tube".  Note, this is in some ways similar to, but not the same , as an "occulting" disk, nor is the result the same.  One of the earliest uses of the Hubble apodizer was during the imaging of the companion "planet" of Beta Pictoris.  It was used to enhance resolution.

Not sure what the central obstruction percentage is within the Hubble.  In typical SCT scopes it is pretty high, around 25 to 30% or so, I believe.  Some years ago experiments showed that reducing the obstruction percentage below 14 or 15% essentially eliminated diffraction problems from that source in the image plane.  Some planetary reflector builders, f ratios up around 9 or 10, have 'downsized' the secondary to around 11%, claiming enhanced fine detail resolution as a result.

Neither gadget should be of too much use with the StarMaster designs, as the secondary has been downsized by Rick to a very acceptable size so that diffracted light in the image plane from the central obstruction is very low.
(contributed by Jim Reid,, of the StarMaster Users group)
I can't help but think that the people who dismiss apodizing screens as useless are simply opinionated individuals who haven't actually tried the device . . . or they've used one that was improperly constructed.  There's no other logical explanation for how anyone could fail to notice the readily apparent benefits!
(contributed by Mike Harvey,, of the SM users group)
Back in 1962, I had an Edmund Scientific 4 1/4 f/10 newt, my first scope.  I used Edmund's apodizing screen on it and it did help cut glare from Jupiter.
(contributed by Peter Natscher,, of the SM users group)

[Editor's Note: I made an apodizing mask several years ago. I used it to split Antares and its companion by rotating the mask until the diffraction spikes were away from the companion, revealing the gray-green star.]

 Leonids 2000
NASA Science News

The Moon is heading for a close encounter with a Leonid debris stream on Nov. 17, 2000. For most stargazers, this year’s quarter Moon during the Leonid meteor shower will be a blazing nuisance. Bright moonlight will overpower many faint shooting stars as the Earth passes through the outskirts of three cometary debris streams during a 36-hour period spanning Nov. 17 and 18, 2000. But for some astronomers, the Moon itself will be the main event if a Leonid meteor storm erupts. "On Nov. 17 [around 0500 UT] the Moon will pass approximately four Earth-diameters from the center of a dust trail left behind by comet Tempel-Tuttle in 1932," says David Asher of the Armagh Observatory, an expert on Leonid debris filaments. "The Moon will be considerably closer to the trail than Earth," raising the possibility of vigorous Leonid activity there.

For more information about the 2000 Leonids meteor shower, stay tuned to

Hope to see everyone at the meeting,