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Subject: SPACE Digest V12 #430

SPACE Digest                                     Volume 12 : Issue 430

Today's Topics:
   E. Journal of the Astro. Soc. of the Atlantic, Vol. II, No. III

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription notices,
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Date: 5 Oct 90 18:03:20 GMT
From: zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!rsiatl!nanovx!chara![e-mail]  (Donald J. Barry)
Subject: E. Journal of the Astro. Soc. of the Atlantic, Vol. II, No. III


                        THE ELECTRONIC JOURNAL OF
                THE ASTRONOMICAL SOCIETY OF THE ATLANTIC

                    Volume 2, Number 3 - October 1990

                       ###########################

                            TABLE OF CONTENTS

                       ###########################

         * ASA Membership/Article Submission Information

         * Kitt Peak and McDonald Observatories: Impressions - Russell Whigham

         * Low-Budget Astronomy - Tony Murray

                       ###########################

                       ASA MEMBERSHIP INFORMATION

        The Electronic Journal of the Astronomical Society of the
    Atlantic (EJASA) is published monthly by the Astronomical Society
    of the Atlantic, Inc.  The ASA is a non-profit organization dedicated
    to the advancement of amateur and professional astronomy and space
    exploration, and to the social and educational needs of its members.

        Membership application is open to all with an interest in
    astronomy and space exploration.  Members receive the ASA Journal
    (hardcopy sent through U.S. Mail), the Astronomical League's REFLECTOR
    magazine, and may additionally purchase discount subscriptions to
    SKY & TELESCOPE, ASTRONOMY, DEEP SKY, and TELESCOPE MAKING magazines.

        For information on membership, contact the Society at:

         Astronomical Society of the Atlantic (ASA)
         c/o Center for High Angular Resolution Astronomy (CHARA)
         Georgia State University (GSU)
         Atlanta, Georgia  30303
         U.S.A.

          [e-mail] or [e-mail]

          ASA BBS: [phone], 300/1200 Baud.

        or telephone the Society recording at [phone] to leave
    your address and/or receive the latest Society news.

        ASA Officers and Council -

         President - Don Barry
         Vice President - Bill Bagnuolo
         Secretary - Ken Poshedly
         Treasurer - Alan Fleming
         Board of Advisors - Edward Albin, Jim Bitsko, Bill Hartkopf
         Council - Jim Bitsko, Julian Crusselle, Toni Douglas, Eric Greene,
                   Larry Klaes, Max Mirot, Paul Pirillo, Patti Provost,
                   Michael Wiggs


        ARTICLE SUBMISSIONS -

        Article submissions to the EJASA on astronomy and space exploration
    are most welcome.  Please send your on-line articles in ASCII format to
    Larry Klaes, EJASA Editor, at the following net addresses or the above
    Society addresses:

        [e-mail]
        or - ...!decwrl!advax.enet.dec.com!klaes
        or - [e-mail]
        or - [e-mail]

        You may also use the above net addresses for EJASA backissue
    requests, letters to the editor, and ASA membership information.

        Please be certain to include either a network or regular mail
    address where you can be reached, a telephone number, and a brief
    biographical sketch.

        DISCLAIMER -

        Submissions are welcome for consideration.  Articles submitted,
    unless otherwise stated, become the property of the Astronomical
    Society of the Atlantic.  Though the articles will not be used for
    profit, they are subject to editing, abridgment, and other changes.
    Copying or reprinting of the EJASA, in part or in whole, is encouraged,
    provided clear attribution is made to the Astronomical Society of the
    Atlantic, the Electronic Journal, and the author(s).  This Journal is
    Copyright (c) 1990 by the Astronomical Society of the Atlantic.


               KITT PEAK AND MCDONALD OBSERVATORIES: IMPRESSIONS

                               by Russell Whigham

        Kitt Peak National Observatory -

        Kitt Peak National Observatory (KPNO) lies just over eighty kilo-
    meters (fifty miles) west of Tucson, Arizona.  Its gleaming observa-
    tory domes are visible for most of the trip from the city, and the
    landscape is essentially barren except for the Saguaro cactus and
    other sparse vegetation.  The nineteen-kilometer (twelve-mile) access
    road turns south off of State Road 86, and its first 3.2 kilometers
    (two miles) of crushed gravel surface are as level as the trip from
    Tucson.  Beyond that, the road begins a steep, serpentine route to
    the 2,070-meter (6,900-foot) mountain summit.  While the road has a
    few guard rails, one should not be in a hurry; I was never guilty of
    exceeding the posted forty kilometers per hour (25 miles per hour)
    speed limit.

        Once at the summit, there is a large parking lot adjacent to the
    Visitors' Center.  Inside is a gift shop well stocked with T-shirts,
    books, and candy bars.  Adjoining the gift shop is the exhibit and
    lecture area that includes models of some of the telescopes at the
    facility and a large screen television which shows various astronom-
    ical videos.

        At the appointed time, we were welcomed by our tour guide who
    recounted the interesting events that were involved in acquiring the
    mountain top from the Papago Amerinds.  The peak was sacred in Papago
    lore.  To convince the tribal elders that they should permit construc-
    tion of the observatory on their mountain, astronomers invited the
    tribal leaders to look through one of the telescopes at the University
    of Arizona in Tucson.  After that visit, the Papago consented to lease
    the mountain for as long as it was used for astronomical research.  We
    then watched a thirty-minute film on the United States' national obser-
    vatories.  Following the film, the tour guide led us on a short walk to
    the 2.1-meter (84-inch) telescope.  He presented another thirty-minute
    lecture inside the dome on the instrument's history, vital statistics,
    and investigations for which this sleeping instrument was used.

        From there, we took a two-block walk to the McMath solar telescope.
    After our guide gave a summary description of this instrument, we were
    allowed to step inside and see a hydrogen-alpha image of the Sun on a
    black-and-white monitor, as well as peer up and down the diagonal light
    path, all from the safety of the glassed-in visitors' gallery.  After
    learning of the engineering and architectural wonders of this telescope
    (liquid cooling and titanium dioxide paint for temperature stabiliza-
    tion), I was amused to see cinder block-size stones used as counter-
    weights.

        While this was the end of the guided tour, we were permitted to
    tour the four-meter (158-inch) Mayall telescope on our own.  An ele-
    vator carries visitors up to the observation level of the eighteen-
    story structure for a magnificent view of the entire mountain top.
    There are more domes here than telescopes at most star parties.
    Another flight up is the visitors' gallery, where the four-meter
    (158-inch) telescope can be seen from the glassed-in area.  A sign
    warning of possible ice on the floor gives a hint that there are
    refrigeration lines in the floor.  They are designed to minimize the
    chimney effect through the dome opening on cold nights.  This is a
    scaled-down version of the five-meter (200-inch) telescope at Palomar
    Mountain in California.

        For further information on KPNO, contact:

        Kitt Peak National Observatory
        State Road 86
        Box 26732
        Tucson, Arizona  85726

        Telephone: [phone]

        Films and lectures are at 10:30 a.m. and 1:30 p.m. daily except
    Christmas (December 25).  Guided tours are at 10:30 a.m. and 1:30 p.m.
    on Saturday and Sunday.

        For further details on KPNO, see the May 1990 issue of EJASA,
    "The Mayall Four-Meter Telescope", by Don Barry.

        McDonald Observatory -

        The sleepy little town of Fort Davis, Texas, stands in stark
    contrast to the metropolis of Tucson.  "Main Street" is only four or
    five blocks long, and while you will not find any "golden arches"
    (McDonalds restaurants) or Holiday Inns here, you will find three or
    four very nice family-style cafeterias and a couple of quaint but
    decent hotels.  Just north of town on State Road 118, enroute to the
    observatory, is Davis Mountains State Park.  The motel-style accom-
    modations were built in the 1930s with Civilian Conservation Corps
    (CCC) labor and are still well maintained.  The price is right and
    the restaurant is great.  A little farther down the road is the Prude
    Ranch.  Now famous as the location of the Texas Star Party held each
    May, it is essentially an ordinary dude ranch the rest of the year.
    At a distance of 27 kilometers (seventeen miles) up the gently curving
    road and rolling hills is Mount Locke, site of the McDonald Observatory.

        The Visitors' Center looks like new and has a good inventory of
    souvenirs, although costs are higher than at Kitt Peak.  Books, T-
    shirts, and posters are available, and there is yet another large-
    screen television playing astronomy tapes.  Adjacent to the Visitor's
    Center is the roll-off roof observatory, which houses a Celestron C-8
    for solar observing and a C-14 and Sky Designs 63-centimeter (25-inch)
    Dobsonian used for public star parties.  A crowd of 25 to thirty people
    had made the 1.6-kilometer (one-mile) drive to Mount Locke's two-thou-
    sand-meter (6,600-foot) summit when the tour began.  Following a wel-
    come by the tour guide with a summary of the history of the astronomy
    program at the University of Texas and identification of the various
    facilities on the mountain, we were led up to the observing floor of
    the 268-centimeter (107-inch) telescope.

        After a litany of facts, feats, and figures about the huge instru-
    ment, our guide raised and lowered the observing floor, slewed the
    telescope several degrees, rotated the dome, and opened the shutter
    doors (only one meter (39.37 inches) or so to limit the amount of day-
    time heat from entering the dome).  He then returned the telescope to
    its normal position and started tracking at the sidereal rate.  He
    pointed out the different foci, (prime, Cassegrain, broken Cassegrain,
    and coud), showed how the entire end ring/secondary assembly was changed
    with a bridge crane to change the effective focal length, and told how
    he and other amateurs on the staff were permitted "joy rides" during
    the rare hours when the telescope was not being used, making visual
    observations at the coud focus.

        Two weeks before, the mirror had just been realuminized in the
    lower floor of the four-story dome.  A cryogenic flask and Charge-
    Coupled Device (CCD) were attached to the Cassegrain focus with an
    ordinary C clamp.  At twilight, the shutters are opened a few meters
    for temperature equalization.  A canvas inner shutter keeps out dust,
    flying insects, and birds during this time until dark.  After about
    twenty minutes, the guide slewed the telescope back to its normal
    position again to demonstrate the tracking rate.

        I soon learned that my itinerary would allow me to attend the Star
    Party.  On my way to this event, I fantasized about seeking out some
    of the celestial objects which are just at the limits of my telescope
    in the fairly light polluted skies of my home.  I was surprised to
    find that at least three hundred people had come out in the middle of
    nowhere for the star party.  As a result, the C-14 spent half of the
    evening on the stars Mizar and Alcor, and the rest of the time focused
    on Messier 57 (M57), the Ring Nebula in the constellation of Lyra the
    Lyre.  The 63-centimeter (25-inch) telescope shared time between M51,
    the Whirlpool Galaxy, and M13, the impressive globular star cluster
    in Hercules. Because of the large crowd, my request to view Omega
    Centauri (which along with M13 were easy naked eye objects) was de-
    nied.  Most of the visitors, including a bus tour group, had never
    looked through a telescope and the star party was geared toward them.

        One of the staff drew off a large group of the novices to point
    out some of the spring and summer constellations.  Others were invited
    to go in the visitors' center to watch video tapes.  At this time I
    was permitted to observe M97, the Owl Nebula.  The owl's "eyes" and
    the central star were easy to view in the Dobsonian with almost a hint
    of color.  As the first-time viewers returned, I had to relinquish my
    coveted spot at the eyepiece.  I stood away from the telescopes and
    easily picked out sixth magnitude stars, enjoying the night sky with
    my own natural instruments of observation.

        For further information on McDonald Observatory, contact:

        University of Texas
        McDonald Observatory
        Visitors' Information Center
        Box 1337
        Fort Davis, Texas 79734

        Telephone: [phone]

        The observatory is open 9:00 a.m.-7:00 p.m., Monday-Saturday,
    1:00 p.m.-7:00 p.m. on Sunday.  Guided tours are at 9:30 a.m. and
    2:00 p.m..  Public star parties are held Tuesday, Friday, and Saturday
    at Sun "set".  The observatory is closed on Thanksgiving Day (fourth
    Thursday in November), Christmas (December 25), and New Year's Day
    (January 1).

        Conclusions -

        I am sure I must have had a silly grin on my face the whole time
    I was at each of these astronomical "holy of holies".  It is inspiring
    just to be near the great tools of some very famous astronomers, know-
    ing that here the deepest secrets of the Universe are revealed to hu-
    manity as reward for their tireless pursuit.  Conversely, it was some-
    what frustrating to be near such amazing telescopes and not be able
    to slip in an eyepiece and have a look around for myself.

        The difference in the two tours was not so much in the facilities
    themselves as in the knowledge of the tour guides.  While the guide
    at Kitt Peak had all the facts right in the lecture and the correct
    answers to my group's questions, I was a bit disappointed when, after
    the tour, I asked about all of the high-pressure sodium lights that
    I had seen the night before in Tucson.  I had read of the ordinances
    restricting HPS lights.  The guide replied, "What is the difference
    between high and low pressure sodium lights?"  An amateur astronomer
    who lives in or near a metropolitan area probably would not have
    answered in this manner.

        At McDonald, the tour guide was an amateur astronomer who knew
    his way around the night sky and obviously loved his job.  In fairness,
    had I visited on another day at either observatory, the situation might
    have been completely reversed.  Both of these complexes have their own
    unique personality and are well worth the effort to reach them at their
    remote locations.

        About the Author -

        Russell Whigham is a member of both the ASA and the Auburn Astro-
    nomical Society (AAS) of Alabama, having served as the AAS newsletter
    editor, vice president, and president.  Russell has taught continuing
    education courses at Auburn University, performed an occultation
    timing for the International Occultation Timing Association (IOTA),
    and has collected four telescopes during the fourteen years he has
    been involved with astronomy.  Russell is joined in his interests
    by his wife Cathy and their two children, John and Suzanne.  By day,
    Russell works as an electronics specialist with South Central Bell.

        For more information on IOTA, write to:  Terri and Craig McManus,
    1177 Collins, Topeka, Kansas 66604 USA.  Telephone:  [phone]


                              LOW-BUDGET ASTRONOMY

                                 by Tony Murray

        Contrary to popular opinion, amateur astronomy is available to
    more people than just the wealthy.  My personal experience in building
    and using a 25-centimeter (ten-inch) reflector telescope shows that
    even those who do not have unlimited financial means can make astro-
    nomical equipment that can produce useful and enjoyable results.

        Around 1982 I finally overcame my "fear" of astronomy and decided
    to start where I could.  I knew that if I waited until I could afford
    a commercially produced telescope, I would never see the stars.  My
    solution was to start with what I could afford; I would build my own
    telescope.

        My first effort, a ten-centimeter (four-inch) reflector on what
    seemed to be the world's wobbliest mount, motivated me to learn and
    see more.  My resolution was to build an adequate 25-centimeter (ten-
    inch) reflector on a mount stable enough to use conveniently and re-
    turn good scientific data.  Partly out of necessity and partly from
    the challenge, I decided to buy nothing I could find, make, or obtain
    used at nominal cost.

        First a friend gave me a two-meter (6.6-foot) section of used
    35-centimeter (fourteen-inch) PVC pipe for the tube.  I painted the
    inside flat black, the outside a glossy black, and then installed a
    homemade mirror cell and focuser.

        Wanting to use the telescope immediately, but preparing for the
    future, I first built a plywood Dobsonian mount which would later be
    replaced with a heavy German equatorial yoke.  At the center of a 2.5
    by 2.5-meter (8 by 8-foot) platform I sank a concrete-filled fifteen-
    centimeter (six-inch) by two-meter (6.6-foot) iron pipe some 1.5 meters
    (five feet) deep in a hole also filled with concrete.  On top of the
    pipe I welded a 40 by 40-centimeter (16 by 16-inch) steel plate one
    centimeter (0.39-inch) thick.  At first this plate served as the base
    of the azimuth axis bearing of the Dobsonian, but later it would serve
    as the base on which the Equatorial would be mounted.  Scrap formica
    provided the azimuth and altitude bearings, and after being lightly
    greased, the telescope moved smoothly to the slightest touch.

        While using the Dobsonian I began work on the permanent mounting.
    The company I work for has a large lot full of salvaged machinery, and
    they allowed me to buy shafts, sprockets, and pillow-block bearings at
    scrap metal prices.  Also located in the scrap heap were two four-meter
    (thirteen-foot) long pieces of 2.5-centimeter (one-inch) channel iron
    used to guide the wheels of the telescope shelter when it is moved from
    over the telescope.  The most expensive part of the telescope mounting
    was the counterweight.  It is made of 30 by 30-centimeter (12 by 12-
    inch) squares of steel plate welded together into a mass eight centi-
    meters (three inches) thick.  The entire assembly weighed 54 kilograms
    (120 pounds)!  My company drilled the four-centimeter (two-inch) shaft
    hole through the counterweight at no additional cost.

        At the other end of the Declination axis I wanted a strong yet
    lightweight cradle to hold the tube.  In the salvage yard I found a
    cracked office chair mat of PVC, which I cut into ten rectangles and
    laminated to make two three-centimeter (1.25-inch) cradles.

        Clever ideas gleaned from years of reading SKY & TELESCOPE
    magazine came to the rescue in building a clock drive.  In the same
    salvage yard I found an aluminum disk 25 centimeters (ten inches) in
    diameter and an office desk drawer glider mounted on two rows of ball
    bearings.  The aluminum disk was attached to the south end of the
    Right-Ascension axis.  Around the disk's edge is an 84-centimeter
    (33-inch) long piece of bike chain, which is attached to the mount's
    base, producing a slip-clutch arrangement.  At the other side of the
    disk, the chain is attached via a steel bracket to a threaded block
    atop the movable part of the glider.

        The glider bottom is attached by a steel bracket to the telescope
    base and allows the chain bracket to move effortlessly back and forth
    on the glider's twelve ball bearings.  A one centimeter (0.39-inch)
    threaded rod eight centimeters (three inches) long turns freely
    through a block attached to the lower end of the glider bottom and
    extends upward through the threaded block atop the movable upper
    glider top.  As the threaded rod is turned, it pulls the chain to turn
    the Right-Ascension axis.  Attached to the threaded rod is a flexible
    cable made from a used drain auger.  By slowly turning the cable's
    wooden handle, I can easily keep a faint star centered in a high power
    eyepiece for thirty minutes or more.  This manual drive will be ex-
    changed for an electrical clock drive when an affordable one can be
    found.

        Finally, the plywood that had been the Dobsonian rocker box became
    a post-mounted weather-tight desk for use right at the observatory
    platform.

        After years of work, the day came to install the telescope on its
    new heavy-duty mounting.  My first big surprise came when one of my
    children walked by on the ground next to the platform.  The star being
    observed jumped like the pen of a seismograph.  The problem was easily
    solved by using hard gasket rubber to isolate the mount from its base
    and the bearing from its mounts.  Since then the telescope has worked
    flawlessly.

        So far my homemade telescope and observatory have been used to
    time more than 425 lunar occultations and several planetoid appulses
    and occultations.  Incredibly, I have never seen the stars in a
    commercially made telescope.  I have the satisfaction, however, of
    making observations through an instrument I made myself.

        About the Author -

        Tony Murray is an active member of the International Occultation
    Timing Association (IOTA).  Tony conducts observations from George-
    town, Georgia, using the home-built instrument described in this
    article.

        For more information on IOTA, write to:  Terri and Craig McManus,
    1177 Collins, Topeka, Kansas 66604 USA.  Telephone:  [phone]


      THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC

                        October 1990 - Vol. 2, No. 3

                          Copyright (c) 1990 - ASA


--
Donald J. Barry       [phone]         | [e-mail]
Center for High Angular Resolution Astronomy | President, Astronomical
Georgia State University, Atlanta, GA 30303  | Society of the Atlantic

------------------------------

End of SPACE Digest V12 #430
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