Pegasus

Volume XXVIIII Issue 1


January / Febraury 2003


In this issue:

1. Presidents message
2. Winter Obseving and Astrophotography
3. The Space Place
4. Observational Hilites for the New Year
5. Upcoming Events
6. Treasurer's Corner - Time to Pay the Dues
7. Black Holes

Pegasus is a bimonthly publication of the Berks County Amateur Astronomical Society

Editor/Desktop publisher: Melody Gardner

E-Mail submissions may be made to: dblhlx@rcn.com


President's Message

Hello and greetings to all from the new team of BCAAS officers. I trust that your holiday season went well. As we begin 2003 it is only appropriate that I update you on some recent changes in club officers. Elections held at the December meeting (aka Christmas party) resulted in a few new officers. Obviously since I’m presenting this, my first President’s Message, it’s a fact that Barry Shupp has decided to retire after a few years at the helm. As one of my first official actions, let me thank Barry for his fine service and in particular for turning over an organization well poised for the New Year. The other change in offices would be at Vice President where Dave Brown, a former Vice President and President, has again stepped forward into a leadership position. Other officer positions and chairs remain unchanged. Linda continues as Treasurer, Barb as Secretary, Melody continues as Pegasus editor and Star party coordinator, Ryan at Programs, Paul as Hot-line coordinator, and Mike our Webmaster. I hope I haven’t missed anyone.

For the coming year, Ryan has again prepared an impressive list of speakers for our membership meetings. Speakers include, Inge Heyer (STScI), Dr. Jacob Trombka (Goddard-NASA), Dr. Dana Bachman (F&M College), Dr. Ruth Daly (Penn State Univ.), and others. In addition we ’ll have our usual member’s night presentations at our July meeting and the August club picnic. And special this year, in October we celebrate BCAAS’s 30th Anniversary with a gala affair at Chef Alan’s with John Dobson as speaker. And then we end the year with the usual Christmas party from hence we just exited for the prior year. For more specific details on which speaker is at a given meeting, please see a tentative listing as posted elsewhere in the newsletter.

And I would be remiss if I didn’t solicit your assistance in writing articles for future issues of the Pegasus. Melody is our editor. The deadline established for submission of material is the Saturday after the monthly membership meeting. Remember Pegasus is a bi-monthly issue. If you have any ideas for a monthly or even for one article, please contact Melody and me to discuss your idea. Please remember, this is an amateur society and we all have some knowledge which could be useful if distributed to the general membership. Please give serious consideration to this request.

The officers, chairs, and coordinators look forward to serving you the membership for the coming year. And we look forward to your support and attendance.

Clear skies,

Ron Kunkel


WINTER OBSERVING AND ASTROPHOTOGRAPHY

With the arrival of clear winter skies, now is an excellent time to go outdoors at night to look at some of winter’s heavenly splendors. With the sky fully dark by 6 PM, one can get out for either a short or long observing session or sessions. Along with clear skies comes winter’s coldness so it is important to dress warmly especially for extended observing sessions. Layers of clothes are the key here, as they will help to trap the bodies heat and maintain a comfortable temperature from which to observe. A nylon- shelled jacket will help to cut the wind if present. Gloves and caps are ideal to keep the hands and head warm, as are insulated boots and thermal socks for the feet. It is a good idea to have something warm to drink like tea or hot chocolate, to help maintain bodily warmth.

If it is extremely cold, do not touch metal objects with bare skin. Use thin gloves which allow fingers to adjust knobs, and pick up objects. If one gets too cold a quick trip inside the house or a warm car may be in order, but avoid white lights as much as possible to preserve night vision. What can we see this time of year? In the early eve ning Saturn begins its ascent into the evening sky and is evident in the East. Leading the way is the Pleiades, one of winter’s most beautiful celestial objects. Already well placed in the South is Pegasus and the nearby Andromeda galaxy. You may be able to see it naked eye, or find it easily with a pair of binoculars. Cygnus, Hercules and Lyra are making their exits in the West, as Orion begins to rise in the East. As the night progresses and Orion becomes more prominent, look for the Orion nebulae in the sword of the mighty hunter. It is a beautiful sight in a pair of binoculars, and a telescope will offer even more detail. Do not expect to see colo r as the human eye does not detect color well at these low light levels. As the night progresses, around 9 PM, Saturn is well up in the sky and should offer some remarkable views of the ring structure. Big brother Jupiter is now rising in the East, but won’t be well placed until about 10PM.

Wintertime provides an excellent opportunity to photograph these celestial gems too. All you need is a steady tripod, an adjustable camera, and a cable release to lock the shutter open. Try to position the tripod away from streetlights etc. Place the camera onto the tripod, aim at the sky object, and then lock the shutter open with the locking cable release. Make sure the lens is focused on infinity! It’s best to practice this before loading the camera with film. For prints use a 400 speed film from Kodak, or Fuji and expose at a variety of times between 10 and 30 seconds with a 50 mm lens. You will get an acceptable picture of Orion for instance, without much trailing. Longer exposures may be taken if trailing is desired. Slide film may also be used and I recommend EliteChrome 400. Snap several "bright frames" indoors at the start of the roll with or without flash to set the spacing of the frames on the film. This will help to prevent accidental cutting apart of night frames by the lab. Make sure to tell them you have astrophotos. Do not take your film to a quick processing facility, but to a photo lab you are familiar with.

The following guide may be used to determine exposures:

Astrophotography Guide

Equipment needed: camera with manual settings including Bulb, sturdy tripod, locking cable release.

Suggested films: Prints- Fuji 400 or 800 ISO; Kodak Max 400 or faster (not Royal Gold). Slides- Kodak EliteChrome, 400 ISO (can be pushed* to 800 or 1200 ISO).

*Push processing- Develop film as if it were 800/ 1200 ISO. Film must be exposed as an ISO 800/ 1200 emulsion. Exposure times may be kept shorter this way.

Faster film will record more (fainter) stars.

Stars will record as different colors.

The longer the time exposure, the longer the star trail will be.

Block out extraneous lights as much as possible.

Constellations and Planets: 28- 50mm lens, 10 seconds – 1 minute.

Star trails: 50mm lens, 1- 30 minutes (depends on sky darkness).

Meteors: 35 or 50mm lens, Expose for a star trail, and point camera where you are seeing meteors in the sky.

Comets: 50mm lens, Expose for 30 seconds, then- 5, 10, 15, 20, 45, and 60 sec. If dark skies, try 2 minutes (will have some trailing).

Thousand Millimeter Second Rule: A 1000 mm lens pointed at the celestial equator will allow 1 second of exposure time with little trailing. Or- Divide 1000 mm by the focal length of the lens being used (mm) for the time in seconds with little trailing:

(T. M. S. R.)

LENS Minimum trail No trail Slight trail
1000 mm 1 sec sec 2-3 sec
500 mm 2 sec sec 4-6 sec
135 mm 7 sec 1.8 sec 14-21 sec
50 mm 20 sec 5.0 sec 40-60 sec
28 mm 35 sec 8.8 sec 70-105 sec

Shoot wide open aperture, or stop down one f-stop for sharper frame edges.

Reference- "Astrophotography For The Amateur" by Michael Covington.

Barry L. Shupp- blshupp@dejazzd.com


THE SPACE PLACE

Enlightened by the Darkness

By Diane K. Fisher

On the clearest of nights, I may see a dozen stars from my suburban backyard near Los Angeles. Unfortunately, my studies of space and astronomy have been confined to books and the pictures taken by others. Seldom have I experienced for myself a truly dark, clear, moonless sky.

One of those rare times was a summer camping trip in Bryce Canyon, Utah. I lay on my sleeping bag in an open area away from trees. I saw millions of stars (so it seemed) and the cloud of the Milky Way streaking across the sky. Nothing of planet Earth was in my view. It was then I glimpsed my true situation in the universe, a speck of dust clinging to a tiny stone hurtling through the darkness of a cold, infinite universe. I was awestruck by the beauty of the stars and the darkness-and terrified!

In the light of day and a more "down-to-Earth" state of mind, I wondered: With around 100 billion galaxies out there, why is it still so dark out there?

Until the 20th century, astronomers thought the universe was infinite. They were perplexed though, because in an infinite universe, no matter where you look in the nig ht sky, you should see a star. Stars should overlap each other and the sky should be blazing with light and hot as the sun. This problem became known as "Olber's Paradox."

Astronomers now realize that the universe is not infinite. A finite universe-that is, a universe of limited size-even one with trillions of stars, just wouldn't have enough stars to light up all of space.

Although a finite universe is enough to explain the darkness, the expansion of the universe also contributes. As light travels from a distant galaxy to us, the space through which the light is traveling is expanding. Therefore, the amount of energy reaching us dwindles all the time, thus causing the color of the radiation to be "redshifted." (The wavelength is stretched out due to cosmic expansion.) The more distant the galaxy, the more redshifted the light. The largest redshift astronomers have measured comes from radiation that was emitted when the Universe was only 300,000 years old. This radiation has taken over 12 billion years to reach us and although it began as infrared radiation, it is now seen as the microwave background radiation.

GALEX (Galaxy Evolution Explorer) is a NASA space telescope that will survey the universe, including galaxies with redshifts that indicate their light has been traveling for up to 10 billion years (or 80% of the history of the universe). Read about GALEX at www.galex.caltech.edu/ . For budding astronomers, print out The Space Place New Millennium Program calendar at spaceplace.nasa.gov/calendar.htm to identify great sky watching opportunities.

Diane K. Fisher is the developer and writer for The Space Place website.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration


Observational Highlights for the New Year

Two challenging telescopic observational opportunities worthy of mention occur early in 2003. One is the probable appearance of the short period Comet Brewington. The other opportunity is the numerous "mutual events" of the moons of Jupiter. And if you find these two observing opportunities a bit too challenging, then certainly don’t miss the ongoing splendid views of the planets Jupiter and Saturn.

Comet Brewington (154P/1992 Q1) is a relatively faint, short period comet making its first predicted return since it was discovered about 10 years ago. By late December, this 11th magnitude comet will have crossed over from Capricorn into Aquarius. During January it will move through Aquarius and on into Pisces. It will reach perihelion (closest approach to the Sun) on February 19th at an expected peak magnitude of 10. The Moon- free evenings during late January and early February will afford the best opportunity to spot this faint interloper to the inner solar system. Refer to the following web site to obtain the orbital elements and coordinates to help find this comet. http://cfa-www.harvard.edu/iau/Ephemerides/Comets/0154P.html

The "mutual events" of Jupiter’s moons offers multiple observational opportunities during the first half of 2003. Twice during Jupiter’s six year orbit of the Sun, the orbital plane of its moons coincides with our line of sight. This is occurring now from December 2002 through July 2003. During this time period the large, inner moons of Jupiter will frequently occult and eclipse one another. Normally we see these moons occulting Jupiter or we see their eclipse shadow move across Jupiter’s cloud tops, in events that last an hour or two. But during this period we will see the moons also occulting and eclipsing one another. These latter events are called mutual events since they involve only the moons. These mutual events are relatively short- lived phenomena lasting from just 10’s of seconds to a few minutes. Observing these events is challenging since each moon’s disk is only about 1 arc-second across thus telescope resolution and image qua lity will be important. Refer to the December issue of Sky & Telescope for more details and a listing of the mutual events for December, January and February. The March issue of Sky & Telescope is expected to list the mutual events through July 2003.

Both of the planets Jupiter and Saturn are well positioned high in the sky above the interfering effects of Earth’s lower atmosphere. Jupiter is in the constellation Cancer and is the brightest object in the sky at magnitude –2.6, aside from the moon. For the best views of Jupiter wait until about 10:00 P.M. until it has risen high enough to get about the turbulent lower atmosphere.

However the planet Saturn is the real treat of the season. Having been at opposition (opposite side of Earth from the Sun) on December 17th, it is thus still positioned high in the Southern sky well above the turbulent lower atmosphere during the night. Opposition occurs every 13 months, but it so happens for this opposition that Saturn is also near it’s perihelion (closest approach to the Sun) and thus closest to Earth. Perihelion only occurs once in Saturn’s 30 year orbit around the Sun. And it also happens the tilt of the ring system of Saturn is near it’s maximum tilt. These three occurrences combine to produce a beautiful and awe- inspiring view of Saturn not seen in 30 years. Saturn is located near the tip of the Eastern-most horn of Taurus. Don’t miss this one.

Clear skies and successful observing,

Ron Kunkel


Upcoming BCAAS Events

This is the BCAAS Speaker Schedule for the coming year:

Thursday, January 9th - Lloyd Adam - Stellafane

Thursday, February 13th - Dr. Ruth Daly - PSU - Beyond the Milky Way

Thursday, March 13th - Dr. Dana Bachman - F&M (Tentative)

Thursday, April 10th - Planetarium Show

Thursday, May 8th - Inge Heyer - Extrasolar Planets - Hubble Space Telescope

Thursday, June 12th - Peter Detterline - The MARS team

Thursday, July 10th - Member's Night*

Saturday, August 9th(?) - Club Picnic (Saturday afternoon)

Thursday, September 11th - Ted A. Nichols II - PLUTO MISSION (Tentative)

Saturday, October 18th - John Dobson as 30th anniversary BCAAS banquet speaker *Note:
There is no regular meeting this month!!*

Thursday, November 13th - Dr. Lawrence Ramsey - HET and PSU (Tentative)

Thursday, December 11th - Christmas Party

*Anyone wishing to do a presentation on Member’s Night, please contact Ron Kunkel to be

scheduled—thanks for your participation!


Treasurer’s Corner

TIME TO PAY DUES!!                          $$$$$

Unless you paid your 2003 dues early, you should have a brightly colored notice attached to this issue of Pegasus. This is a reminder that you need to pay your dues by the end of January in order to avoid that nasty late fee. You can either bring your dues to the January meeting or mail it to me. The check should be payable to BCAAS. My address is 345 Douglass Street, Wyomissing, PA 19610. If you already paid and still received a notice, please let me know. If you think you owe dues and have not received a notice, also let me know. If you joined the club during 2002, your dues have been pro-rated through the end of 2003. There is no late fee for prorated dues.

Linda Sensenig, Treasurer


Black Holes: Feeling the Ripples

—Another contribution by NASA’s Space Place authors

 

Astronomers have finally confirmed something they had long suspected: there is a super-massive black hole in the center of our Milky Way galaxy. The evidence? A star near the galactic center orbits something unseen at a top speed of 5000 km/s. Only a black hole 2 million times more massive than our Sun could cause the star to move so fast. (See the Oct. 17, 2002, issue of Nature for more information.)

Still, a key mystery remains. Where did the black ho le come from? For that matter, where do any supermassive black holes come from? There is mounting evidence that such "monsters" lurk in the middles of most galaxies, yet their origin is unknown. Do they start out as tiny black holes that grow slowly, attracting material piecemeal from passing stars and clouds? Or are they born big, their mass increasing in large gulps when their host galaxy collides with another galaxy?

A new space telescope called LISA (short for "Laser Interferometer Space Antenna") aims to find out. Designed by scientists at NASA and the European Space Agency, LISA doesn't detect ordinary forms of electromagnetic radiation such as light or radio waves. It senses ripples in the fabric of space-time itself--gravitational waves.

Albert Einstein first realized in 1916 that gravitational waves might exist. His equations of general relativity, which describe gravity, had solutions that reminded him of ripples on a pond. These "gravity ripples" travel at the speed of light and, ironically, do not interact much with matter. As a result, they can cross the cosmos quickly and intact.

Gravitational waves are created any time big masses spin, collide or explode. Matter crashing into a black hole, for example, would do it. So would two black holes colliding. If astronomers could monitor gravitational waves coming from a super- massive black hole, they could learn how it grows and evolves.

Unfortunately, these waves are hard to measure. If a gravitational wave traveled from the black hole at the center of our galaxy and passed through your body, it would stretch and compress you by an amount far less than the width of an atom. LISA, however, will be able to detect such tiny compressions.

LISA consists of three spacecraft flying in formation-a giant triangle 5 million km on each side. One of the spacecraft will shoot laser beams at the other two. Those two will echo the laser signal right back. By comparing the echoes to the original signal, onboard instruments can sense changes in the size of the triangle as small as 0.0000000002 meters (20 picometers).

With such sensitivity, astronomers might detect gravitational waves from all kinds of cosmic sources. The first, however, will probably be the weightiest: super- massive black holes. Will "feeling" the ripples from such objects finally solve their mystery, or lead to more questions? Only time will tell. Scientists hope to launch the LISA mission in 2011.


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