CONSTELLATION

The Official Publication of the Bucks-Mont Astronomical Association, Inc

____________________________________________________________________________________________________________________________________

VOL XV, NO 11w NOVEMBER 2000
Scott Petersen, Editor
____________________________________________________________________________________________________________________________________

2000 BMAA, Inc

Looks Like I Missed It!

- by Alan Pasicznyk

Due to a seemingly interminable amount of dental work, and an ensuing flu virus, I was not able to fully attend this year's Stella Della Valley. Being in charge of the on-site duty roster of "who does what", I was only able to arrive at the campsite Friday afternoon to deliver the red candles, parking flashlights, change the bathroom bulbs to red, and post copies of the job list. Then it was time to go home, as the chills and hot flashes that accompanied the flu began to get the better of me. All of which lead me to consider exactly what it was about Stella Della Valley that I missed the most.

Over the years, I have overheard a few people remark that maybe SDV doesn't have the most pristine night skies in the world for doing amateur astronomy. Maybe the flea market isn't as good as it could be. Or the guest speaker isn't as well known as say, Patrick Moore. Is it really worth all the effort to coordinate, help out with, and pack all the camping and astronomy gear for this one weekend? All I can say to anyone out there who is thinking along those lines is, just try this: Get miserably sick the weekend of the campout as I did. You'll find out exactly what you missed, and why it is that yes, it really truly is worth the effort to make this event. And if you want, I'll even save you the trouble of getting sick just to find out the answer. The answer is this...

On Friday afternoon, as I was preparing to leave SDV to go home, I figured that I should at least pick up my SDV badge. I went to the picnic table where Marian Shearer was doing the registration with all the name tags scattered on the table. As I looked down I could read the names of all the people that I knew would be arriving, people that I knew from the club, others that I would only see once a year at this time and place, all of them people that I would not be sharing this weekend with, this year at least. Leaving that table full of badges and going home was the hardest and saddest thing for me to do that Friday, and I came to realize just what it is that makes SDV special.

It's not just the clear skies, or the flea market, or the various speakers or doorprizes (believe it or not) that I missed the most. It was the people! Those from our club who help out, others from other clubs that I only see once a year, THAT is what makes SDV what it really is; a friendly comaraderie of amateur astronomers sharing their hobby. Accordingly, I would like to thank all the members, especially Marian Shearer who took on the responsibility and chaired the event, Jim Shearer as co-chair, Ed Radomski, the van der Speks and all the people who helped park cars, as well as others listed below. You made this event happen!

Many thanks again to the following people:

Bob Jackson Brad Miller George Reagan Rick Lentz Antoine Pharamond Steve Bryant

Brian Daly Ed Murray Bernie Kosher Paul Kohler Linda Van der Spek Peter Van der Spek

Bob Post Mike Bowdren Scott Petersen Harvey Scribner Gwen Bryant Ken Wieland Bruce Collier

So with that I'll close by saying that it's still not too early to start to "Think Clear Skies" for next year, and eat more Vitamin C !

Alan Pasicznyk

On-Site Personnel Coordinator, SDV XIV

* * * * * * *

- BMAA member Alan Pasicznyk is long-time SDV volunteer coordinator and chair of Transient Phenomenon. [ -ed]

____________________________________________________________________________________________________________

Astronomy 101 is an informal Q & A session before each General Meeting at 7:30p,

November 1: The Watery Quarter of the Sky, with Peter van der Spek

(rescheduled from October)

___________________________________________________________________________________________________________

The next BMAA General Meeting is scheduled for Wednesday, November 1 at 8:00p

The (Postponed) Election of Officers for 2001 will be held at this meeting

____________________________________________________________________________________________________________________________________

The CONSTELLATION is the official publication of the Bucks-Mont Astronomical Association, Inc, a 501(c)3 non-profit organization incorporated in the Commonwealth of Pennsylvania and exists for the exchange of ideas, news, information and publicity among the BMAA membership, as well as the amateur astronomy community at large. The views expressed are not necessarily those of BMAA, but of the contributors and are edited to fit within the format and confines of the publication. Unsolicited articles relevant to astronomy are welcomed and may be submitted to the Editor.

Reprints of articles, or complete issues of the CONSTELLATION, are available by contacting the Editor at the address listed below, and portions may be reproduced without permission, provided explicit acknowledgement is made and a copy of that publication is sent to the Editor. The contents of this publication, and its format (published hard copy or electronic) are copyright 2000 BMAA, Inc.

In an effort to transmit the CONSTELLATION electronically to the membership of BMAA, please provide a current e-dress to the Editor. Abbreviated issues are available on the web site, but complete editions will be e-mailed to members in good standing.

Submission deadline for articles is the 15th of the month prior to publication.

SCOTT PETERSEN
CONSTELLATION EDITOR
WYCOMBE PA 18980-0333
TEL: 215/598-8447
FAX: 215/598-8446

___________________________________________________________________________________________________________________________________________

BMAA MESSAGELINE - 215/579-9973

BMAA WEB SITE: bmaa.freeyellow.com/

bmaa@ixc.net

Bucks-Mont Astronomical Association

2000 Calendar Of Events

StarWatch Chairman: Ed Radomski - 215/822-8312, ejrado@prodigy.net

Information Line - 215/579-9973

______________________________________________________________________________________________________________________________

Forum

More BMAA WebSite Traffic

In an effort to expand this newsletter, I (as editor) am initiating an on-going column that is available to all BMAA members and others to maintain a dialogue regarding club issues. I will reprint all comments, and I encourage e-mails which are easier to reproduce here.

BMAA webmaster, Jim Moyer, has submitted more comments received on the BMAA website (excerpted below):

. . . I quickly ran into Ed Murray, the new president of Bucks Mont Astronomical Association. He is a very outgoing and likable person and was very excited about having the Questar members at the star party. He really made me feel at home and was very pleased (actually amazed) to hear that we had people coming from as far as Colorado, Georgia and Texas.

He probably asked me three times over the course of the weekend if we were having a good time, what they could do to improve the star fest, etc. He was genuinely concerned with our satisfaction. They did a great job- I had nothing to add or complain about.

The star fest is held at a Boy Scouts camp and has permanent tents with built in beds, plus a couple of cabins (with heat!). These are pretty decent accomodations for the boonies and I think I will stay there if/when we do this again.

It's a good group of people and I hope we do this on a regular basis. This is an event that is definitely worth attending, not just for the Q festivities but for the star gazing too. If you missed this you missed the opportunity to compare at least 12 Q's against a hundred or more other telescopes of all shapes, sizes and designs. What a blast! - Neil

* * * * * * *

. . . Alpha Piscium is a great double for the Q! It's actually closed a bit to 1.48" now.

Quoting from Muirden's book, "This binary pair has a period of about 700 years, and the stars are expected to be at their closest (0.98" apart) in 2074." He lists the pair as 4.2, 5.2; 1.67"; 277deg (1985)1.48"; 264deg (2000)

Alpha Piscium is not classified as a "fixed" double star, and both its position angle and separation are seen to change with time. It is also interesting to note that in 1859 when T.W.Webb first published double star information for Alpha Piscium in his classic "Celestial Objects for Common Telescopes", he listed its position angle as 335.7deg and separation as 3.6".

I was lucky enough to observe this pair during the excellent seeing at Stella-Della-Valley on the 50th anniversary weekend. I like to use the 8mm eyepiece with barlow (280X) for such close doubles. In this view the 1st. diffraction ring from each companion fell just outside the Airy disk for the other with blackness between. Jim Perkins (of Questar) also had a look through my scope ('89-BB-Zerodur) and agreed that it was resolved superbly. - Jim

* * * * * * *

. . . I was gratified to recently discover that BMAA's web site ranks in the upper 20% of web sites in Google's Web Directory listing for amateur astronomy groups. (See http://directory.google.com/Top/Science/Astronomy/Amateur/Groups/ )

This is particularly significant since Google ranks sites by relevance: "Web Pages Ordered by PageRank"

Unlike other directories that can only list web pages alphabetically regardless of how good they are, the web pages in the Google directory are ordered according to Google's patent-pending PageRankTM technology. This means that the most relevant and highly-regarded sites on any topic are listed first ... not buried deep within a list of other pages."

I know that having the CONSTELLATION on-line has helped to boost our relevance significantly. Thanks for your efforts. - Jim

* * * * * * *

- BMAA member Jim Moyer may be reached on the website. [ -ed]

_______________________________________________________________________________________________________________________________

The Knife Edge Test in (at) Focus

- by John C Deitz

Previously we discussed the construction of a knife edge tester for use at the completed telescope. One of the primary applications is in the study of atmospheric dynamics.

The beauty of the knife-edge test is that it demonstrates aberration along the entire light path. High atmosphere, low atmosphere, local air mass effects, the tube and the optics. The difficulty is that it is sometimes unclear just where, along this long line of light, the problem comes from. With a little practice the user can determine where the problems are. In this article we will explore the effects of atmosphere, specifically tube currents.

Center, using an eyepiece, a second or third magnitude star in the field of view. If the telescope has no drive mechanism then Polaris is a good test star. Now replace the eyepiece with the knife edge tester. Holding your eye about a foot back look through the hole in the knife edge tester and center on the star. Moving your head closer, right up to the opening of the test eyepiece, the light of the star will be seen to fill the entire field of view. Now move the tube (gently, if by hand) to bring the knife edge in from the right. If the knife edge is outside the best focus the shadow of the knife will be on the left. If inside the focus the knife will seem to come from the right (the same side that the knife is actually located on). Move the knife edge in and out of the focuser, or use the rack and pinion to find a place where the entire ball of light is found to darken evenly and quickly. This is the best position to see tube currents. UNDER PERFECT CONDITIONS (atmosphere and optical train) this spot would yield only a quickly dimming UNIFORM ball of light. Any departure is spherical aberration. This article will explore optics effects introduced by varied density air masses inside the tube any immediate environment.

In general, the Newtonian suffers most from the effects of different temperature air within the tube, followed by catadioptric and lastly refractors. Fortunately, many of the common problems have simple cures! The first trick is to determine just where the problems are!

Volumes of air of VARIED DENSITY (temperature) ACROSS the light path are an important limiting factor in telescope performance. Any "drafts" inside the tube are likely to cause serious trouble that exceeds Rayleigh's limit.

While the knife edge tester is very sensitive to variations in refractive index, it is NOT always immediately apparent where the problem air comes from. Take you time in making these observations, and keep a notebook. Some may be "one night stands". Some are seasonal (I have one 10in that is mostly useless in the winter), while others are found most of the time. Some are related to the observing environment (hot air rising from the driveway and into the open end of the scope- cover the mirror end with a plastic bag to prove this one).

Here are some hints that may help you determine just where the problem comes from:

1) Fast moving disturbance that moves from one side of the tube to the other is most likely high atmospheric. Look for rolling airmasses after the passage of a jet. My south-southwestern quadrant is limited by air traffic.

2) Slower moving air is likely closer to the tube and harder to sense direction of movement. If it moves from one side of the tube to the other it is likely external to the tube. If a strong vertical component is seen it is likely hot rising air. This may come from the neighbor's house, chimney or bathroom vent.

3) The third set of disturbances you can do something about. These are flows immediately adjacent to the tube and inside the tube. If it is hot air from the ground try asking someone to walk in front of the tube while using the tester. If the passage of the body changes the pattern of motion you will have found the problem. If closer to the tube try fanning the air with a large piece of cardboard and look for changes.

4) Problems inside the tube can often be permanently fixed. Mixing air inside the tube often moves slowly. If in doubt, use a "dollar store" fan to blow air into the tube. If air is seen coming from one side of the tube then hold a finger up in front of the tube to identify the edge involved. See Illustration #3 and identify probable sources of air (look for- focuser mount, diagonal holder, mirror clips, air rising from the ground and getting into the tube etc.). Rotation of the tube may help determine the source. Having identified the source it becomes easy to effect a cure. Air from the observers breathing finds it's way into the tube where the focuser meets the tube. Silcone cenment cures this one. Air rising from the focuser in a catadioptric is more difficult (some are equipped with fans to establish equilbrium). Use of a prism (as opposed to a mirror diagonal) may be just the thing. I have found it necessary to install fans to blow the air out of a Newtonian. Use of a larger tube may allow moving air to rise out of the light path ( and reduces the need for baffles). Don't forget the old trick of a fan blowing behind the mirror or drawing air from the side of the tube near the mirror surface. Of course, the ultimate cure may be an optical window...

ILLUSTRATION 1

With the knife edge OUTSIDE the focal plane and introduced from the RIGHT the field is seen to darken from the left.

ILLUSTRATION 2

With the knife edge INSIDE the focal plane and introduced from the RIGHT the field is seen to darken from the right.

ILLUSTRATION 3

When a position is found that produces even daring of the field the test is most sensitive. Try to identify the sources of air here.

ILLUSTRATION 4) Use of two different size tubes will allow air to move against the tube wall, out of the light path AND reduces the number of baffles.

John Deitz has been providing recent articles regarding telescope building and maintenance. He can be reached at johncdeitz@cs.com. [ -ed]

______________________________________________________________________________________________________________________

Observing Tips

Starting over - the Messier objects

- by Bernie Kosher

I've been writing this column for years, and observing on and off for 35. I've been asked many times how many objects I can claim, or how many Herschels or planetaries. Have you seen this object? How about NGC 2101?

Usually, I have some idea if I've seen a specific faint fuzzy, especially if I can check on a chart. But how many? I have no idea whatsoever. I am perhaps the worst paper work person on the planet, and certainly one of the least organized.

So follow along, or walk beside, as I start over, from the beginning, with a lot of knowledge of what I should see and the experience of digging out faint objects. Thus it's not like a total beginner, but I'll try to keep it that way. Join me monthly, it should be fun. Send me your notes and we'll compare. From the city, country, suburbs or Peruvian Andes, let me know.

What tools shall I use?

Any scope is useful on the M objects. Messier used up to about 4" aperture. So almost all of us are better equipped, but lack his experience and clear dark skies. Messier observed from Paris, at about 50 degrees north latitude, We have the advantage of his finds riding much higher in the sky.

A 4.5" f/14 refractor of good optical quality, a 5" f/5 refractor and for wide field, along with an 8" f/5 reflector on occasion. Plus binoculars of course. Our star charts will be Edmunds mag 6 Star Atlas and a Planisphere. Any basic scope and chart is enough to get us started. I have no setting circles of any kind, but have no objection to those who wish using them.

Occasional reference will be made to the Tirion and Becvar charts, plus a Norton's Star Atlas. And a close-up of the Coma-Virgo area (The Realm of the Nebula) to identify the zillion galaxies clumped there. Warm clothes and a comfortable lounge chair for binocular observation. A red light, dew zappers for the scopes and something to keep the mosquitoes away are nice additions. Comfort is important.

When shall we observe?

Any clear evening will do, with preference to moonless nights. Many of the brighter objects are visible in full moonlight, but the least haze in the air will obscure them if it's very brightly lit.

Where?

Most of us are city dwellers. Try your backyard. You might be surprised. Certainly, you will quickly learn the constellations, and learn to aim your scope. You might even find Camelopardalis, or (gasp) Lacerta. Very few city folks have a good low horizon, but overhead can be remarkably clear. I live outside Trenton, but overhead I have had 5.5 or better on occasion.

And what if I can't find anything?

Then try again. Don't knock yourself out. It's very rewarding to find your first M object. And the second, and the 103rd. Or 110th. Or whatever you decide to use for the 'missing' objects.

Let's clear up something. The original complete catalog, by Messier, contained a listing of 103 objects. Some other self styled expert(s) added 104-110 because they claimed he had observed them. This is just my opinion, and we know what opinions are like. Messier himself did not list them in his final catalog. So call the objects from 104-110 what you will.

Where should I start?

Anywhere you like. I'm starting just west of the zenith and working my way eastward, solely because the westward objects are heading toward the horizon, while the eastward are rising. Observing on the meridian is best, but we must allow for what time we have to observe.

In October and November, Hercules is rapidly setting and Lyra and Cygnus are just beyond the zenith. Good place to start. The fall constellations are giving way to winter, and the cold air is bringing some of our clearest evenings. Don't let a bit of cold slow you down.

I'm writing this on Wednesday the 25th of October. In future installments, I'll share a log.

Tell me what you've done also. This is the point of our hobby, so let's share it. Failure to locate an object is good input also. It may help others. So, help me out here.

* * * * * * *

- BMAA member Bernie Kosher provides the monthly 'Tips' column. He can be reached at bkhere@optonline.net. [ -ed]