August, 1999

A note from the editor...

The dog days of summer are upon us. Fortunately, the summer so far has brought a number of good nights for observing, hopefully a sign of a reversal of the past year's trend.

The annual MAS picnic was held June 12 at the Yanna Research Station. About 35 MAS members, family, and friends attended. Elections of new officers were held: Neil Simmons replaces Rod Holt as vice-president, and Mike Puffer joins Dave Weier as board member at-large. Otherwise, your contingent of officers looks much like it did last year.

This issue of Capitol Skies is packed with good stuff. If you've ever wondered what it's like to chase a lunar graze, Bob Manske's account will put you right in the middle of the hunt. Astrophotography is more accessible than you might have thought. New member Mike McDowell shatters the conventional wisdom that says a standard 8 inch SCT is not good enough to take great pictures. A report from the treasurer with important renewal and magazine information, and even a bit of poetry round out this issue.

Enjoy!
 
 

Calendar of Events

August 10
Space Place guest speaker Dr. Peter Sobol, historian of science:
"Friend, Foe, Saviour, or Villain: Extraterrestrials in Human Imagination," 
7:00 pm

August 13 
Regular meeting at UW Space Place, 1605 S. Park Street, 7:30

August 14 
Observatory meeting at YRS 4:30 pm

Sept. 10
Regular meeting at UW Space Place, "European Solar Eclipse," 7:30

Sept. 11
Observatory meeting at YRS 4:30 pm
 

 
 
 
 
 
 
 

April 19: Aldebaran Graze by Bob Manske

Weather on the High Plains of Colorado east of the Rocky Mountains is difficult to predict. All afternoon clouds had been pouring off the peaks of the Front Range just beyond Denver and by three o'clock they were thickening rapidly. We had come from all over the United States to observe; from states like Wisconsin, Arizona, California, Missouri, Maryland, Colorado of course, and now the grazing occultation of Aldebaran by the Moon was being seriously threatened. Yet the weather forecaster who entered the small lecture room in the planetarium of the Denver Museum told the anxious attendees of the national convention of IOTA, the International Occultation and Timing Association, that all would be well. Even though another low pressure trough was coming in from Wyoming he predicted that as the Sun set, the air flow over the mountains would no longer produce clouds and that the sky would clear over Kiowa Colorado, from where we planned to observe the graze, thirty five miles southeast of Denver, by 9:00 PM.

A star is said to be occulted whenever the Moon passes between an observer and a star. Because the Earth is rotating in an easterly direction, we see the Moon rise in the east and set in the west, but because the Moon is revolving around the Earth in an easterly direction, the moon slowly moves eastward relative to the star while both drift westward in the sky due to the Earth's rotation. And you don't have to wait long to see the shift in relative position take place. The Moon moves eastward compared to the stars very nearly one of its own diameters every hour.

The star we were interested in on that Sunday evening in April was Aldebaran, the brightest star in Taurus. A very faint shadow of Aldebaran was going to fall on the Earth as the Moon passed between the star and the planet. Of course, no one would be able to see that shadow, it's far too faint to be observed, but it would be a shadow, nevertheless, and anyone standing in the shadow would find their view of Aldebaran blocked by the Moon.

Imagine standing somewhere on the Earth directly in the path of a star's shadow, waiting for it to reach you. If you look at the star instead of the ground, and the Moon is west of it, you will see the Moon closing in on it at the rate of one lunar diameter per hour. At last the edge of the Moon passes in front of it and the star, in this case, Aldebaran disappears. The shadow, along with the Moon, moves on to the east. If you are standing exactly where the center of the Moon passes between you and Aldebaran, about one hour later, if the Moon is still up, the star reappears. With any luck at all.

Now imagine that you are not standing smack in the middle of the shadow but roughly one thousand miles north or south of that point. Now you are located at the edge of the circular shadow so the Moon does not take very long to transit the star. Aldebaran disappears and very soon reappears. If you are standing exactly at the edge of the shadow, you may see Aldebaran disappear and reappear several times and very quickly at that as the mountains and valleys on the edge of the Moon pass in front of the star. This is called a "grazing occultation".

On the evening of April 18, the southern edge of the shadow was predicted to trace a line across the Earth's surface angling east southeastward passing just south of Denver. IOTA's President David Dunham and the Graze Expedition Leader, Bob Sandy of the Kansas City Astronomical Society, had chosen to observe the event from the town of Kiowa, Colorado, about thirty five miles southeast of Denver. As the Moon's shadow raced across the Earth it would reach Kiowa at about 9:44 PM local time. We were going to be there. But would the clouds be there, too?

"In fact," the weatherman was saying, "it's clearing off faster than our computer models are predicting." Even if it didn't clear completely, we were told the clearest skies would be between us and the Rocky Mountains. Since the Moon would be only about 12 degrees above the western horizon, we'd be able to look under the cloud cover and observe the occultation.

"Whatever you do," he warned, "don't go further out into the high plains and definitely don't go to Kansas, that's where this stuff is headed."

It was hard to believe that the clouds, thick as they were, would clear off in time. And the thought of peeking under a cloud deck wasn't too appealing, since the atmosphere might be so turbulent that it would cause Aldebaran to blink wildly and make it difficult to determine the exact moments of actual disappearance and reappearance.

A backup plan quickly evolved. Bob Sandy had made arrangements with the proprietor of the Kiowa Feed Store to open up especially for us at 7:30 PM and to remain open until we were done with the graze. Now Bob told us to meet at the store a half-hour earlier. If the clouds had not satisfactorily cleared away, we could move west quickly, up into the area near the Lockheed-Marietta Titan missile plant just southwest of Denver.

At 6:55 PM I pulled into the dusty parking lot of the Kiowa Feed Store. The lady who ran the store had put up some welcoming notices on the marquee out in front. Since she didn't know we were coming early, the store was still closed and there was little to do but mill around and watch the sky until Sandy and Dunham arrived. And the sky was clearing! As the minutes passed by it seemed that Kiowa was in the middle of a huge hole in the clouds. I could see rain to the north and south and it was very dark to the east. Part of the easterly darkness was caused by the lateness of the day, of course, but there were also thick, rainy looking clouds out there. Overhead, they had thinned almost completely, but not yet completely enough to allow an unobscured view of a planned satellite iridium flash. To the west, a blue-dark lane of clouds slowly dissipated. The Feed Store lady arrived and put on instant coffee and doughnuts for us. We committed to observing the graze from the Kiowa location.

By nine o'clock I was at my assigned station, about a half a mile south of the eastern edge of town. Star hopping into the Moon was not difficult, located as it was near bright, first magnitude Aldebaran. I acquired the view in the telescope and then set up my other equipment.

There is no major technical difference between observing a lunar graze and observing the occultation of a star by an asteroid. In both cases the amount light of the star changes suddenly. When an asteroid crosses in front, the star dims or disappears completely. With the Moon, the star simply vanishes, except maybe in the case of Aldebaran. The basic idea is to time the changes in brightness as accurately as possible to the nearest quarter second when using purely visual means or much more accurately using video recorders. In either case you should have at hand a short wave radio capable of receiving the official time signals from radio station WWV which broadcasts continuously on frequencies 2.5, 5, 10, 15, or 20 MHz. Use as much magnification as you can without significant image deterioration. Since I would be observing visually my technique would be to simply turn on WWV, start recording with an audio tape recorder and look through the eyepiece. When the limb of the Moon intercepts the star, I holler "bang" as loud as I can, and when the star reappears I holler "bang" again. This method of marking the moment is not IOTA standard procedure. The "book" recommends that you say "D" when the star disappears and "R" when the star reappears. "Bang" became my personal procedure the first time I ever saw it happen. I was so excited when the star vanished that the word "bang" just jumped out. Technically, though, "D" and "R" are better and unambiguous. I'll work on changing my habits.

As the lunar limb approaches the star the added light from the illuminated portion of the Moon showering into the telescope tube causes the star to appear to dim appreciably, by as much as a magnitude or more in the minutes just before occultation. For this reason grazing occultations of stars fainter than about magnitude 10 or 11 are usually not attempted. A fainter star is extremely difficult to see under these conditions.

Other observers were located south of me along the road leading out of Kiowa and also some were northeast of the town. The farther south you went along that road, the closer you got to the point where you would not see an occultation. From that location you would see the Moon sail close by Aldebaran but never occult it. What we are doing then by lining observers along the road, roughly perpendicular to the trace of the lunar shadow along the ground, is giving each observer a slightly different vantage point. Each observer will record slightly different times of disappearance and reappearance. The graze leader, Bob Sandy, will use this information to draw a silhouette profile of the Moon's limb, accurate to a couple of hundred feet, mapped from a range of a quarter of million miles using off-the-shelf equipment. Some of the video equipment especially is on the expensive side, but it's still cheaper than golf!

Adding their observations to the group personally led by Sandy are Gerry Samolyk and Chris Hazeltine who observed the occultation just a few moments earlier from a site in Utah. Gerry and Chris are both members of the Milwaukee Astronomical Society and Gerry, of course, is also a member of the Madison Astronomical Society. They produced excellent video coverage of the event. Gerry showed his tape at the Observatory Committee meeting at YRS on May 15th.

Aldebaran is not your usual star. It is huge. It demonstrated its size last summer when we observed an Aldebaran graze near Nashville, Tennessee. Gerry, incidentally, observed the same graze several hundred miles of east of Nashville. Most observers, Gerry and I included, reported that when the Moon's limb encountered the star there was no sudden disappearance. Instead the star seemed to fade into the Moon slowly, taking perhaps a third of a second or so to completely vanish. In the case of a double star you will often see the star step down in brightness when the first component goes behind the Moon followed by the second component moments later. Aldebaran is in fact a triple star; the system contains an 11.3 magnitude companion and another of magnitude 13.6. There were reports, Gerry's and mine among them, that during an interval of reappearance the star did not return to the same brightness it had when it disappeared the first time. The generally accepted view is that the Moon's limb was actually cutting across the disk of the star! However there are others who claim that that is highly unlikely or even impossible. Their interpretation is that the 13 magnitude companion is visible while Aldebaran is below the lunar horizon. The problem with this is that 13th magnitude is much fainter than is easily visible that close to the Moon. In addition, the observed magnitude during the reappearance was much brighter than 13th magnitude.

I hope someday to share with you the combined results of the expeditions. I don't even have my own data. That, along with all the other audio and video tapes were turned over to Bob Sandy for reduction and compilation. It is quite a large task and will take several months.

I can say that I observed four events, a slow initial disappearance which lasted about half a minute, then a reappearance which persisted for about three minutes followed by another brief disappearance (and, yes, I hollered "bang!" every time). Gerry recorded six events on video tape. I have asked him to bring that tape along to show at a regular meeting.

The last time we had a successful graze in the Madison area occurred several years ago when Gerry led a successful expedition composed of members of both the Madison and Milwaukee Astronomical Societies to a point near Janesville. Weather has caused us to cancel every one since then. We'll try again in September, clouds permitting.

Memberships, magazines, and new members

MAS welcomes new members Paul Basanowski, Chao-Hsu Chang, Michael McDowell, Kent Wade and Arthur Zimmerman to the Society.

To all other members, yearly dues billing will be mailed in July, and should be in your hands by the time you read this. Please return your dues and magazine renewal payment (if any) to me by the end of August.

Important note: MAS members will be receiving renewal notices from Sky & Telescope and Astronomy (depending on which magazines the member has subscribed to) over the next few months. MAS members should ignore these reminders if they have subscribed to these magazines through the Society because the Society will be sending a group renewal for both magazines in October of this year. The group renewal will renew most subscriptions as of January. However, if a member's subscription will be terminated before December, please call me at 238-9556. Members will be making the choice of which magazines they would like to subscribe to when they receive their dues notice in July.

The subscription rates for Sky & Telescope and Astronomy have gone up over the last year. The group rate for Sky & Telescope is now $29.95/yr and the same rate for Astronomy is $29.00/yr., still exceptional rates.

Joe Keyes, treasurer

Your turn (opinion and editorial comments)

Dear editor,

As editor of this society's newsletter you have a responsibility to identify submissions that are political in nature and allow opposing viewpoints equal exposure. By "political" I mean any statement critical of how this organization is run. When publishing concerns as potentially contestable as the statement by MAS members Ellestad, Goddard, Greiner and Helt [ad hoc memo in June 1999 Capitol Skies], it is considered only fair that those who hold different opinions be offered a chance at rebuttal within the same issue. It makes for better reading because the whole story is presented.

When supplied with an accusation of negligence or impropriety, then it becomes all the more important to extend an offer to reply within the same issue, especially when that issue is the last one before an election and the parties involved are elected representatives of the MAS. When differences arise it is generally expected that both sides of the issue be allowed to present their differences in a equal forum as it required in a democracy. Publishing the concerns of MAS members Ellestad, Goddard, Greiner and Helt without a response from the Board of Directors in the May newsletter was a disservice to the membership of the MAS. It raised questions without providing any answers.

Neil Simmons

Neil Simmons is absolutely correct that I should have invited a reply in the June Capitol Skies to the ad hoc memorandum. But I should also point out that three of the four authors of that memo were in fact, at the time, elected officers or board members of the MAS. Given that situation, I felt that the memo deserved to be printed in the newsletter at the earliest opportunity. Moreover, the memo had already been presented to the MAS membership at the May meeting, where a motion was passed that the MAS leadership would present its response at the August meeting. Many MAS members await that response, which will be fully covered at the earliest opportunity in this newsletter. -ed.
 
 

Getting started in astrophotography by Mike McDowell

I have been interested in Astronomy for most of my life, but it wasn't until after seeing the movie "Contact" a few years ago that my passion for the hobby was renewed. In December 1997 I sold my Meade 4.5" Newtonian and purchased a Celestron Celestar 8 Standard. My intent at the time was to use it strictly for observational use. It wasn't until several months later when my fiancée, Becky, suggested that we connect her SLR camera to the telescope before I gave astrophotography a thought.

Skipping for the moment piggyback astrophotography, we decided to get a T-Adapter to attempt lunar shots at prime focus. A T-Adapter allows you to attach your camera, with a T-ring, to the prime focus of the telescope. This is used for terrestrial photography and short exposure lunar and filtered solar photography. We were a bit disappointed with our first results - all were blurred due to vibration caused by the mirror flip-up. Locking the mirror up prior to opening the shutter fixed this. The picture of the moon shown here was from our second role of film.

Next, I purchased a piggyback mount for my C8 and the next clear night headed out to Indian Lake Park. A piggyback mount allows you to attach a camera to the top of the telescope. This way, the camera can photograph with its normal or wide angle lens while guding through the telescope. I took several exposures, 5 to 10 minutes with Fuji 400 film, of the Big Dipper and other constellations. The following day, I dropped my film off to be processed. When I picked up my pictures I was dismayed because there were big red blobs in the upper right corner of every picture. As it turned out the exposure indicator light inside the view finder of the camera was the culprit. The red light entered into the exposure field. The solution? There was no problem removing the batteries since they are only used for the exposure indicator and have little function for astrophotography. The next batch of pictures turned out great.

Purchasing a tele-extender, the next type of astrophotography I attempted is what I still consider to be the most difficult - short exposure eyepiece projection of planets. A tele-extender is a hollow tube that allows you to attach a camera to the telescope with an eyepiece installed. The great difficulty lies in trying to get the planet into focus through the viewfinder of the camera. I think I could spend an entire evening second guessing my focus. So far I have taken pictures of Venus, Mars, Jupiter and Saturn with great success.

With success at prime focus, piggy back and eyepiece projection, I decided to plunge further down the "slippery slope" by taking a stab at long exposure deep sky astrophotography. Totally addicted, I purchased additional equipment: a radial guider, illuminated reticle eyepiece, declination drive and hand controller. My first target was M13 using Kodak Royal 1000 film. While my guiding was fair (little streaking of stars), the picture was pretty grainy. Improved results were achieved using Fuji Superia 800 film. Additionally, to decrease exposure times I acquired a f/6.3 focal reducer. The photograph of M42 below represents the culmination of my winning combination:

C8 Standard @ f/6.3
Fuji 800 Superia Film
Yashica FX-3 Super 2000 Camera
15-20 minute exposures
 M42: Fuji Superia 800 X-TRA, 20 minute exposure - prime focus @f/6.3, November 27, 1998.  Gibbous moon: Fuji 400, 1/250th second exposure - prime focus @ f/10, June 3, 1998.

It wasn't too long before Becky realized she created a monster and wanted equal time with her camera. It soon followed that I purchased my own manual SLR. It's a year later and my apartment walls are covered with framed 8x10 shots of the planets, nebulae, galaxies, and the sun and moon. For a complete library of my work, please feel free to visit my personal web page.
 
 

Book Review

Full Moon

by Michael Light and Andrew Chaikin (contributor)

Add this one to your "must buy" list right now. Light was able to obtain NASA's master negatives from the Apollo cameras and scan them electronically. Though we've all seen many of the pictures before, we've never seen them like this. The images are so clear you'll have to resist the impulse to brush the lunar dust off Dave Scott's suit as he looks for another sample on the lunar surface. This book is irresistable, even if you're not a lunar observer. One glance in the bookstore and you'll have to have it. A retrospective by Chaikin follows the images, which are presented as they should be, with no descriptions or captions.
 
 

Einstein and God Shoot Craps by Steven Fortney

God looks exactly like Einstein.
He is the CEO of a chain
of Casinos called
Happy Chance Heaven.

His Avatar and namesake, Albert
by name, engages Him,
shooting craps.

7 come 11 snake eyes
boxcars. God pitches
the dice against green felt.

(The house gathers at
the table, they are wide-eyed;
the stakes are immense!)

7 come 11 snake eyes
boxcars. God cleans
up. Albert is broke.

Albert cries O symmetry
asymmetry third order
interpolation, standard model,
string theory chaos: a GUT
and a TOE.

I can't believe, he says,
That you shoot craps
with the Universe!

God twirls his gray moustache
Poor guy, he says, I do; but here's
my little secret. Sometimes I shoot
straight, sometimes I don't. Either way
(here he takes Al's last dollar)
the Universe wins.

And both ways I throw dice
(Yes I do), just to see
what happens.

I know that upsets you,
but is this a comfort?
The dice we just played with?

They're loaded.


Tracking the outer planets with binoculars by John Rummel

Uranus and Neptune are thought of as difficult objects by most amateur astronomers. This need not be the case. Uranus is visible to the naked eye on most nights ­ if you know exactly where to look. Neptune is much fainter, but still relatively easy to spot in good binoculars or a small telescope ­ again, if you know just where to point.

Found accidentally by William Herschel in 1781, writer Bob Berman has described the discovery of Uranus as the most significant scientific discovery in history. Since the dawn of recorded history, the solar system had consisted of the Earth, Sun, Moon, and five planets. With one announcement, Herschel doubled the size of the solar system and ignited the search for more solar system objects. As bright as it is, you'd think it would have been found much sooner, and it was. Many astronomers had observed and cataloged Uranus as a star (first recorded observation was in 1690!), but until Herschel, nobody recognized it for what it was. The idea of Saturn being the furthest planet from the sun was so ingrained, nobody ever thought there might be other planets.

While the discovery of Uranus was accidental, Neptune's uncovering was the result of a purposeful search. By the early 1800s, astronomers who monitored the orbit of Uranus noticed that its predicted position always varied slightly from its observed position. Such misbehavior by a planet was serious trouble since Newton's calculations had been so successful in describing and predicting the orbits of other solar system bodies. Astronomers deduced that there must be still another planet beyond Uranus with a sufficiently strong gravitational pull that it was pulling Uranus out of its expected orbit.

Working independently, French and English mathematicians calculated the possible location of the unknown planet, and published their findings in 1846. That same year the German astronomer Johann Gottfried Galle discovered the planet within 1 degree (2 full moon widths) of that position, a triumph of mathematics and astronomy!

Observer's Challenge for September

Fortunately, you can reproduce the thrill of discovery from any dark sky location in September. Simply find a dark sky site, away from city lights. Ideally, do your observing during the first half of the month, before the moon begins to intrude. Using the chart below, familiarize yourself with the constellation Capricornus. This southern constellation is visible in the mid-north latitudes only during the late summer and fall, and is at its best in September. Look for it well above the southern horizon at about 10 pm. A dark site is a must though, no stars in this constellation are brighter than 3rd magnitude, much dimmer, for instance, than the stars in the big dipper.

Two stars in the diagram are labeled, Theta and Sigma Capricorni. Find these two stars and you're an easy hop away from the planets. The fine lines drawn near the stars represent the paths the planets will follow from the 1st day of September to the last, both planets are traveling left to right, or east to west.

With your binoculars, carefully examine the area surrounding each star. Sketch all the stars that you see. Wait two or three nights, and then go out and do the same thing again. You're looking for the subtle movement of the two planets. With persistence and a little luck, you'll experience the thrill of observing an object that very few of your friends have seen.

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