ASTRONOMY CLUB OF TULSA

Astronomy Club of Tulsa Meeting

Friday Sep 15, 2000 at 7:30 P.M.

Come at 7:00 PM for telescope viewing from parking lot!

Where

Room M1 inside Keplinger Hall, the Science & Engineering Building at TU.

Enter the parking lot on the East Side of Keplinger Hall from

Harvard and 5th Street. This will take you directly toward the

staircase to enter the building. Room M1 is the first room on the left.

John Land

Asteroids - Do they pose a threat to us on earth? If so, can astronomers play a role in identifying potentially hazardous asteroids?

On Aug 26 an new asteroid was discovered which now joins 263 other PHAs - a Potentially Hazardous Asteroids. Asteroid 2000 QW7, a new Earth-approaching Amor asteroid, was discovered on August 26th by a 1.2-meter telescope atop Haleakala in Maui, Hawaii. The telescope is used by Eleanor F. Helin (JPL) and her colleagues to hunt for such Earth-crossers through a collaboration of her Near Earth Asteroid Tracking team and the Maui Space Surveillance Site. According to Gareth Williams, who calculated the MPC's preliminary orbit, asteroid 2000 QW7 averages 292 million kilometers (1.95 a.u.) from the Sun in a rather eccentric 2.7-year orbit inclined 4O to the ecliptic. It is classed as an Amor-type object, ranging from just outside Earth's orbit to as far out as the main belt of asteroids (roughly midway between Mars and Jupiter). At present this interplanetary wanderer does not pose an impact threat to Earth - a good thing, because based on its brightness it may be about a half kilometer (0.3 mile) across.

According to the Asteroid Impact calculator an asteroid of this size traveling at a typical 20 Km/sec would make a crater 6.3 km (3.5 miles) across and 1500 feet deep! It would have an impact the energy of 7444 Megatons of TNT. (All of the world's Nuclear Weapons equal only 10000 MT) An impact this size would pack the energy of a killer 8.2 earthquake! This asteroid missed us passing just 3 million miles beyond Earth's orbit. You may think this is a great distance but it takes Earth less than two days to cover this distance in its orbit around the sun. A day or two difference and mother earth could be suffering from a major headache!!

At our club meeting we will be watching a National Geographic Video entitled "Asteroids" that discusses the problem of NEO's Near Earth Objects that include asteroids and comets. We'll hear noted astronomers such as David Levy, Gene and Carolyn Shoemaker discuss their efforts in searching for these cosmic bullets in the night sky.

See http://www.skypub.com/news/news.html for a detailed ephemeris of 2000 QW7.

http://janus.astro.umd.edu/astro/impact.html - Asteroid impact calculator

In Memory of Joel Fream

On Aug 19th we lost one of our valued club contributors. For several years Joel Fream has done the computer work to put together our club newspaper "The Observer" On Aug 19th Joel was killed in the crash of his single engine aircraft. Joel will be remembered for serving spirit in helping out the Astronomy club, radio club and small rural law enforcement groups in Oklahoma.

Marc Chouinard - a former club President now living in Texas wrote this tribute to Joel.

I met Joel when I was attempting to make a newsletter that would become an observing tool as well as communicate club events. I had recruited David Stine for his wonderful column(called "Comet Talk" at that time) to join Don Cole (Great seasonal observing guides) and myself as regular contributors, but we lacked production capabilities to reflect the content quality. After seeing the new content, Joel Fream telephoned me.

Although Joel was not much involved in observing anymore, he still had an interest in the club and invited me over to see the newsletter he had prepared for his radio club. I was very impressed and excited that Joel agreed to produce our newsletter in the same fashion. Richie Shroff organized much of the content, as he had been doing so well for many years, while Joel did formatting and production. Joel also contributed interesting columns about astronomical enigmas and curiosities. Very much of the success of "The Observer" is owed to Joel, who formatted the visual appeal that still compliments the ACT newsletter today. There is no doubt that the form of communication he helped develop has touched many budding Astronomers.

I have a picture of Joel and his German shepherd in front of the pier at the observatory. He helped during construction of the building; a time when we were taking on this great challenge while both establishing a great newsletter and a rigorous observing schedule. Without him, we would not have been as successful. I shall always remember him for stepping up during a critical time in the club's history.

Up coming Club meetings and events:

Club Meetings:

Oct 20 at Tulsa Air and Space Center

Nov 10 - TBA Club Dinner

Dec 15 at TU

For our October meeting we will meet at the Tulsa Air and Space Center near the Tulsa Airport. TASC has a wonderful collection of Aircraft and Space exhibits including a real F14 Fighter and an actual control panel from the Apollo control center. They have over $2 million in pledged funds toward the construction of a new facility which will include Tulsa's first planetarium. I have asked them to share with us their vision and plans for this new facility. You'll not want to miss this meeting. Donations to TASC are recommended at this meeting to contribute toward the new facility.

Club Officer Elections: At our October meeting it is traditional for us to elect a new slate of officers for the coming year. In addition to officers we have three elected board members and a number of appointive offices. We are looking for members who are dedicated to the future of the Astronomy Club of Tulsa and willing to contribute their time and energies to promoting the club and its activities. You don't have to know a lot about astronomy but do have to be willing to share your enthusiasm for learning more about this marvelous universe and sharing it with others. If you are that person, then please contact one of the officers or board members about your desire to serve.

Club Observing Night - Fri Sept 22 Observing at Dusk Rain Date Sat Sept 23

We had at least 40 people at our August observing night despite the high day time temperatures it was very pleasant after dark. Due to the extreme dry conditions we must impose a NO SMOKING and NO FIRES ban at the observatory.

URGENT TELESCOPES and VOLUNTEERS NEEDED:

We are getting lots of calls for groups to visit the observatory or for us to come to schools with our telescopes. Most of these groups make generous donations toward the expenses of our observatory. We especially need help in November. Please contact Gerry Andries and confirm your commitment to help with these events. We also still need help completing repairs and mowing at the observatory.

Contact - < Gerry Andries e-mail > - Phone

The following is the current schedule of star parties and public groups.

All events are at the RMCC unless noted otherwise:

SEP

    09-22-00 Fri 19:00 Club Star Party - Back Up Date 9-23

OCT

    10-07-00 Sat 18:00 Ast Club of BA High school

    10-20-00 Fri 19:30 ACT Meet ( at the Tulsa Air and Space Center)

    10-27-00 Fri 17:00 Club Star Party

    10-28-00 Sat 17:00 Backup for 10-27-00

NOV

    11-03-00 Fri 17:30 Catoosa Gifted & Talented Class

    * * 11-04-00 Sat 17:00 Public Star Party (at TCC West Campus)

    11-05-00 Sun 17:00 Collinsvile High School

    11-10-00 Fri 18:30 ACT Annual Dinner Meeting

        (Location to be determined)

    11-15-00 Wed 19:30 Tulsa Public Library Astronomy Lecture

        (at Hardesty Library)

    11-16-00 Thu 17:00 Club Star Party - Leonid Meteor Shower

    11-17-00 Fri 17:00 Club Star Party-- Leonids

    11-18-00 Sat 17:00 Backup for 11-17-00

    11-29-00 Wed 19:00 So. Tulsa Baptist Church

Atoka Star Party - Picnic Sat Oct 23 - Each year the Texas Astronomical Society holds its annual picnic at their Atoka, Oklahoma dark sky site. There are usually over 100 people and 40 to 50 telescopes at the all night event. They have completed construction of their observatory featuring a fully automated 15 inch Meade telescope. Tickets are $5.00 each but we must give them advanced notice to prepare for us. Please reserve your ticket by our Sept 15 meeting.

Okie-Tex Star Party - Sept 24 to 30 Mile High Dark skies in Oklahoma Panhandle

Okie-Tex has long been a favorite autumn retreat under the canopy of night. Since its move last year to the pristine ebony skies of the Black Mesa, Okie-Tex is rapidly becoming known as THE PLACE to be! Registration is only $30 per person plus $7.00 per meal. However you must get your registration and meals reserved by Sept 10th! Several of our members are already signed up so the HEATED bunkhouse beds are going fast.

Email - starpartyinfo@okie-tex.com 

Mail Okie-Tex Star Party Box 128 Mustang, OK 73064

Observing Manuals Available

You can get started in astronomy with one to the Astronomical League Observing Projects. We have a few the "Universe Sampler" booklets to get you started learning the night sky. We also have a few of the "Messier Observer's" and "Herschel I " manuals for the more advanced or ambitious observers. Plus a list of the features to be observed to earn your Lunar Certificate.

For a look at these and other programs, contact John Land or check out the Astronomical League. 

Asteroid Searching

Joseph A. Dellinger

Since moving to Houston I've started asteroid hunting with the Fort Bend Astronomy Club. I'm afraid I'm really more one of the "groupies" than a central member, although I've made up for my lack of experience with raw beginner's luck: 8 of the 9 discoveries the group has made this year happened on nights when I was one of the observers! I certainly won't complain if this run of good luck continues. :-)

While nine might sound like a lot of asteroids, it's not really all THAT many. The real fanatical amateurs out there, of which a handful exist, single-handedly discover asteroids at 10-20 times the rate our club does. Mostly this difference is a simple function of how much time we spend looking. First of all, the moon has to be out of the way, or there's just not much point: most of the asteroids still left to be discovered are 17th magnitude or dimmer (so if you can't see Pluto, forget it). That wipes out half the month. Then, of course, there is the possibility of bad weather. Houston is not famous for its clear dry skies. Our observatory is located at Brazos Bend State Park, in the middle of a mosquito-infested swamp crawling with alligators a few feet above sea level. Many observing nights end when the still cloudless sky dissolves into a haze of white light-pollution-lit fog, which we then have to carefully drive home through. Most observing nights we're keeping a wary eye on the relative humidity as we work, watching it slowly creeping up to 100% and trying to finish our observing run before that happens.

There are the "personal" factors too. Most of us have day jobs and can't stay out observing too much past midnight on workday nights. (It takes me a full hour to drive back home from the observatory.) It seems every night something unexpected goes wrong: the CCD cable stops working, there is a power failure, the computer recording the data crashes, we forget to write down the exposure time or get confused as to where we are, somebody trips over a cable or bumps into the scope...

Finally, there are several "teams" in the club all vying for telescope time, of which the "A-team" is only one. A couple of weeks before each new moon cycle, the nights are divvied up between the teams, and we get about 1/3 of them assigned to us. If our nights happen to correspond to cloudy ones, then we're out of luck.

The club can use two different telescopes out at the George Observatory at Brazos Bend: an 18-inch and a whopping big 36-inch. Unfortunately, while it sounds impressive the extra light-gathering power of the 36-inch is not worth its much smaller field. The A-team only ever uses the 18-inch. Per the club's agreement with the park, we have to man the scopes for public education every Saturday night, without fail (even if it's cloudy). In return, we get to use the scopes on other nights.

Bill Dillon, the leader of the A-team, always tries to sign up for the Saturday nights closest to new moon. After showing the last few boy scouts camping in the park M13 (ooooh!), at 10PM our public duties end and we get to boot out the few remaining visitors. That is what Bill, Max Eastman, and I did Saturday, August 26, a rather memorable night.

Bill plans out the night's observing run beforehand if he can. There are three basic kinds of work to do: a "search field", looking for something new, a "follow-up", making continuing observations of a previous discovery of the club's to keep it from getting lost, or "requested observations", observing something that NASA or the minor planet center has requested us to look at for them. (Twice now the club has helped provide last-minute orbital updates of near-Earth objects so that Arecibo could image them using radio waves as they whizzed close by.)

That Saturday we needed to do a "follow-up" field, but while we waited for that to get high enough to shoot, we did a search. To do a search, we usually pick out a "bright" (8th magnitude or so) star reasonably near the opposition point that the Minor Planet Center knows of no asteroids near. It is convenient to be able to pivot around a reasonably bright star: our telescope does not have computer go-to capability, and it's easy to get "lost in space" without such a reference point. (Although, Bill is legendary in his ability to star-hop his way to wherever we need to go.)

We place the bright star in a corner of the CCD field, and shoot a 4-minute exposure. About 2/3 of the time the telescope tracking was OK, so we keep the image and move on. Otherwise, we re-shoot and try again, possibly balancing heavy books on the telescope mount or tightening or loosening screws on the drive trying to get the @!%&*@ scope to stop misbehaving. (At least that's better than having to discard an image because we forgot to write down when we started the exposure! That happens a lot more often than you'd think, especially when it gets late.)

After each successful image we move the star around to the next corner, and shoot again, so working our way around the squared circle. By the time we've finished 4 shots and are back at the starting point usually at least 30 minutes (and more often an hour) has passed. We're then ready to shoot a second image for each location, and after those, a third.

At some point during this process, when things have been going well so we aren't in a hurry, we have to stop to "take a dark". That's an image of complete blackness taken with the shutter closed. The resulting image, which looks something like a field randomly scattered with uniformly bright pinpoint stars, is then subtracted from all the images to get rid of that "hot pixel" camera noise from the images. (Forgetting to open the shutter again after taking a dark is another good way to waste time.)

Finally, we get to the real excitement: the chance for a discovery! For each of the four corners, we load the 3 images we've taken over the preceding couple of hours and "blink" them, looking for a "star" that moved between our exposures. (By waiting at least 15 minutes between exposures, we give the asteroids a chance to move and betray themselves.) If we're in a hurry, or tired, we sometimes try to stop after only two, but experience shows that there almost always appears to be SOMETHING moving in any pair of images. We really do need the third to tell the random noise in the camera apart from something that is truly moving in the sky.

That Saturday we had the good fortune of being able to borrow a large-format CCD camera from Rice University, so we had a BIG field to search (half a degree across!). And we were lucky: of the four search fields, there were asteroids moving in three of them. One was a "known" asteroid we expected to be there, so it didn't count. The club numbers their discoveries consecutively, so the other two became "FBAC 56" and "FBAC 57".

The minor planet center won't give any credit for a discovery unless it is observed on at least two SEPARATE nights, so with those discoveries we had just created some high-priority follow-up work for the next A-team observing night. We had also created several hours' work for Bill on Sunday --- he had to measure the exact locations of the asteroids off our CCD images, report that information to the minor planet center, and extrapolate those positions into the future for our follow-up.

We then moved on to the second business of the night, following up on a discovery of the club's from the previous new moon. In the days before the near-Earth-asteroid-searching robot LINEAR, the club spent a lot of its time following up on their own previous discoveries. Nowadays, it often seems we are locked in a race with a tireless juggernaut: half the time even our "discoveries" turn out to have already been discovered by LINEAR (but not yet listed, so we don't know until later that we didn't get credit for our "discovery"). On the plus side, though, LINEAR is now doing most of our follow-up work for us.

This particular object was discovered while the club was making routine observations of Comet Tempel 1, an object NASA needs observations of to help plan a future rendezvous with a deep-space probe. The newly discovered asteroid, designated 2000 PO8 by the minor planet center, was moving slowly enough that evidently LINEAR wasn't interested in it. (It is designed to look for near Earth objects, which move fast.) So we have to do all the work of keeping track of this one ourselves, like back in the good old days of the late 1990's. And we got lucky again: we made another discovery, FBAC 58, in the field with 2000 PO8. (Many of the club's discoveries have been made during follow-ups.)

After follow-up on succeeding nights (two by our club, and one by Paul Comba when we ran out of observing nights and had to ask for help --- Paul is one of those folks who discovers more asteroids in a month than our club has discovered in 4 years), our 3 discoveries were designated by the minor planet center "2000 QL26", "2000 QM26" and "2000 QA71". Amazingly enough, the club gets credit for discovery on all three of these; LINEAR must have been having a stretch of cloudy weather! (We aren't always so lucky --- we thought we had a discovery the following Monday night, but got scooped on that one.)

Now we get to follow these for the next several years! If we're lucky, "our" asteroids will turn out to have been observed in the past, and our current observations will be sufficient for the minor planet center to link our discoveries back to those. In that case, their orbits will suddenly become much better determined, so the day when their orbits are so well determined that they are candidates for permanent naming and numbering will come sooner (maybe next year!) rather than later (four or five years from now). If we're unlucky, the previous observations will prove better than our own --- and "our" asteroids will be re-categorized as merely "recoveries of previously known but lost asteroids". In that case we will lose the right to name them, alas.

So far the club has yet to get to name a single asteroid... but some of their discoveries from previous years are now getting really close!

And here's my asteroid link:

http://sepwww.stanford.edu/oldsep/joe/Astro/2000CB41.html

Here's a complete roster of the club's discoveries:

http://www.geocities.com/amicustellarum/discoverers.html

September SKY FORUM

By Don Cole

Continuing on with this month and for the next few months, I would like to delve more into stars, the different types, their make-up and what makes them tick and do some of the strange things they do.

Classification of Stellar Spectra

The photographic study of stellar spectra was initiated in 1885 by the American astronomer Edward Charles Picketing at the Harvard College Observatory and carried out principally by the American astronomer Annie J. Cannon. This research led to the important discovery that stellar spectra can be arranged in a continuous sequence, based on the relative intensity of certain absorption lines occurring in the spectra. The observed variations within the sequence provide clues to the age of the different stars and their stages of development. (See Spectrum below).

The various stages in the spectrum sequence, which are designated by the letters O, B, A, F, G, K, and M, are characterized especially by variations in the intensity of the hydrogen lines that occur throughout the sequence. In addition, the lines of other elements become prominent at different stages. Subscripts from 0 to 9 are used to denote gradations in the pattern within each class.

Class O: This group is primarily characterized by the lines of helium, oxygen, and nitrogen, besides the hydrogen lines. The O group, which comprises extremely hot stars, includes those showing bright-line spectra of hydrogen and helium, as well as those exhibiting dark lines of the same elements.

Class B: In this group the helium lines attain maximum intensity at the subdivision B2 and fade progressively in higher subdivisions. The intensity of the hydrogen lines steadily increases throughout the subdivisions. The group is typified by the star e Origins.

Class A: This group comprises the so-called hydrogen stars with spectra dominated by the absorption lines of hydrogen. A typical star of this group is Sirius, the Dog Star.

Class F: This group comprises stars in which the so-called H and K lines of calcium and the characteristic lines of hydrogen are strong. A notable star in this category is d Aquiline.

Class G: This group comprises stars with prominent H and K calcium lines and less prominent hydrogen lines. The spectra of many metals, notably iron, are also present. The sun belongs to this group, and the G stars are therefore frequently called solar stars.

Class K: This group comprises stars having strong calcium lines and lines indicating the presence of other metals. The violet light of the spectrum is less intense, compared with the red light, than in the classes previously mentioned. Arcturus typifies the group.

Class M: This group comprises stars with spectra dominated by bands resulting from the presence of metallic-oxide molecules, notably those of titanium oxide. The violet end of the spectrum is less intense than that in the K stars. The star a Origins is typical of this group.

All these characteristics are compatible with the conclusion that stars of these classes are all of similar chemical composition and are arranged in a temperature order from hottest to coolest. The absolute surface temperatures of the various star groups are approximately the following: O, 22,200 degrees C (40,000 degrees F); B, 13,900 degrees C (25,000 degrees F); A, 10,000 degrees C (18,000 degrees F); F, 6650 degrees C (12,000 degrees F); G, 5540 degrees C (10,000 degrees F); K, 3870 degrees C (7000 degrees F); and M, 1760 degrees C (3200 degrees F). The interior temperature of the average star is about 20,000,000 degrees C (36,000,000 degrees F).

Double Stars

More than half of the stars in the sky are actually members of two-star (binary) systems or multiple-star systems. Some nearby double stars appear separate when viewed telescopically, but many more are detected as doubles only by spectroscopic means. A double-star system consists of two stars that are physically close to each other and that revolve in an orbit around their common center of mass. The British astronomer Sir William Herschel first recognized such double stars in 1803.

Spectroscopic binaries, first identified in 1889, are not visually separable by the telescope but can nevertheless be recognized by means of doubling or broadening of the spectrum lines as the star pair revolves. When one component moves away from earth and the other approaches it as they revolve in their orbit, the spectrum lines from the receding star shift toward the red, while those from the advancing star shift toward the violet (see Doppler Effect below).

Another type of double star is the so-called eclipsing variable. Stars of this type are composed of a brighter and a darker component. As seen from earth, when the orbit is such that the darker star eclipses the brighter one, the intensity of the light coming from the star fluctuates regularly.

Investigation has shown that about one of every two or three stars visible with telescopes of moderate size is a double star of the physical-double type. Many thousands of visual binaries and many hundred spectroscope binaries have been studied intensively. Such stars are the main source of information about stellar masses.

Variable Stars

All stars probably vary slightly in their brightness on a more or less periodic basis, including the sun. Such variations may be scarcely measurable. Some stars, however, change greatly in brightness and are called variable stars. There are many types. Some repeat cycles with almost clocklike precision; others are highly irregular. Some may require only hours or days to return to a starting brightness; others may require years. The brightness of such stars may change almost imperceptibly or violently.

The most spectacular variable is the so-called temporary star, or nova. Novas may brighten up to as much as 200,000 times the sun's brightness by blowing off perhaps a hundredth or a thousandth of 1 percent of the sun's mass at speeds up to 960 km per sec (up to 600 MI per sec). Some novas repeat this process, periodically until they lose too much mass to continue. Although supernovas are similarly named, they are a far more catastrophic phenomenon and not periodic at all. They represent the true explosion of a star, sometimes brightening for a few days to 10 billion times the sun's true brightness before fading away permanently. They leave behind expanding wreckage seen as bright gaseous clouds, or nebulas; the Crab nebula is an example, first observed from earth as a supernova in 1054. Sometimes a pulsar is also left as a remnant in the center of the wreckage. Novas occur fairly frequently in the Milky Way, perhaps one or two being observed each year, but supernovas are much rarer. The most recent supernova in the Milky Way appeared in 1604, although one in a nearby galaxy drew great attention in 1987.

Many variable stars change their brightness by pulsating, that is, by expanding and contracting somewhat like a balloon. One important type, named Cepheid variables after d Cephei, repeats their brightness cycles rather accurately. Their periods range from about a day to hundreds of days, and they are all hundreds of times more luminous than the sun. The longer the period of a Cepheid variable, the greater the average brightness of the star. This period-luminosity relation, discovered by Henrietta Leavitt of the Harvard College Observatory, has proved invaluable in measuring the stellar distances, particularly to nearby galaxies of stars. Only the period and average apparent brightness of a Cepheid need be observed to provide a measure of its distance. Novas and especially supernovas are also important distance measures because their incredible brilliance at maximum light makes them observable at huge distances in the universe.

Variable stars are of unusual interest because their variation is usually caused by some peculiarity of their internal structure that develops with age. Variable stars thus can reveal information about stellar evolution. Supernovas, for example, have burned up their nuclear fuel and must blow off matter because they become unstable as they collapse gravitationally.

The eclipsing variable, mentioned in the previous section, varies because of external rather than internal causes. The star Algol in the constellation Perseus is typical. Algol is a double star composed of one bright and one comparatively faint component with an orbit in a plane almost exactly in the line of sight from earth. As the darker component eclipses the brighter, the apparent brightness of the pair falls off sharply, and a similar but less intense diminution occurs when the brighter component eclipses the darker. Astronomers have observed many thousands of eclipsing variable stars, which are valuable in measuring stellar masses.

*** Astronomy Dictionary ***

SPECTRUM: A rainbow like series of colors, in the order violet, blue, green, yellow, orange, and red, produced by splitting a composite light, such as white light, into its component colors. Indigo was formerly recognized as a distinct spectral color. The rainbow is a natural spectrum, produced by meteorological phenomena. Passing sunlight through a glass prism can produce a similar effect. The English mathematician and physicist Sir Isaac Newton advanced the first correct explanation of the phenomenon in 1666.

A device for producing and observing a spectrum visually is called a spectroscope; a device for observing and recording a spectrum photographically is called a spectrograph; a device for measuring the brightness of the various portions of spectra is called a spectrophotometer; and the science of using spectroscopes, spectrographs, and spectrophotometers to study spectra is called spectroscopy.

DOPPLER EFFECT: in physics, this is the apparent variation in frequency of (any) emitted wave, such as a wave of light or sound, as the source of the wave approaches or moves away, relative to an observer. The effect takes its name from the Austrian physicist Christian Johann Doppler, who first stated the physical principle in 1842. Doppler's principle explains why, if a source of sound of a constant pitch is moving toward an observer, the sound seems higher in pitch (due to compression of the waves), whereas if the source is moving away it seems lower (due to lengthening of the waves). An observer listening to the whistle of an express train from a station platform or another train can hear this change in pitch. The lines in the spectrum of a luminous body such as a star are similarly shifted toward the violet if the distance between the star and the earth is decreasing and toward the red if the distance is increasing. By measuring this shift, the relative motion of the earth and the star can be calculated (see Red Shift).

RED SHIFT: A shift toward longer wavelengths observed in the lines of spectra of celestial objects. The American astronomer Edwin Powell Hubble, in 1929, linked the red shift observed in spectra of galaxies to the expansion of the universe. Hubble theorized that this red shift, called the cosmological red shift, is caused by the Doppler effect and hence indicates the speed of recession of the galaxies-and, by using Hubble's law, the distances of the galaxies.

So until next month Dark Skies and Steady Seeing to You...

Asteroid Vesta

John Land

You can find an Asteroid from your own backyard!  The asteroid Vesta is easily visible in a pair of binoculars and is well placed in the evening sky.

To find Vesta locate the “teapot” asterism of the constellation Sagittarius about 1/3 of the way up in the south - southwest sky after dusk.  The four stars that make up the “C” shaped handle are shown on the map below.  Next find the arc of three stars just above the handle that make the “teaspoon” or hat of Sagittarius.  Center your binoculars on these stars and then move ONE binocular field to the LEFT.   Then slowly move your binoculars down one field and you should be in the right area to find Vesta.  Look for the two stars X3 and X1 in the top of your view to point the way.  Vesta has just finished its retrograde (backward) motion and is slowly fading.  However it is still 6^th magnitude and easily visible in binoculars.  Make a sketch of your view for several nights in a row and you will be able to see Vesta move among its background of stars.

For more advanced telescopic observers, I received this letter from Larry Robinson describing the Astronomical Leagues Asteroid observing Certificate.

Dear John and anyone else interested in asteroid work:

As coordinator of the Astronomical League's Asteroid Observing Program I would like to volunteer to help you with your asteroid observing programs in your clubs.  There are many enjoyable observing opportunities at any given time and if I can help you in target selection or any other detail to make it possible for you to observe asteroids let me know. As you may know there is a fine program available for observing asteroids and just about any kind of records of observations are acceptable to submit for the award. The basic award is for observing 25 different asteroids at two different positions.  This can be on the same night or different nights.  You may submit a drawing or positional measurements if you do CCD work and reduce the data.  For this achievement you get a handsome certificate and your name listed in the Reflector.

The Gold Award is for 100 asteroids. This award includes a certificate and a lovely lapel pin.  This achievement is also listed in the Reflector.  So far there have been only four basic and three gold awards earned, so it still possible to be in the top ten for this one.

It is really an easy award to earn, since at any given time there are many bright asteroids in the sky. It is just a matter of finding them and looking at them.  I observed over 25 last night myself.  There are many resources on the net for getting this information.  If you want to know, more email me and I will help you.

**********************************************************************

Larry Robinson    Sunflower Observatory   IAUC/MPC Observatory Code 739

Olathe, KS 66062  email: lrobinsn@ix.netcom.com  homepage: http://btboar.tripod.com/