335 lines
17 KiB
Plaintext
335 lines
17 KiB
Plaintext
SUBJECT: THE MARTIAN CHRONICLE FILE: UFO3329
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PART 2
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******************************************************************************
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T h e M a r t i a n C h r o n i c l e
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April 1990 No. 2
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The electronic newsletter by the International Mars Patrol (I.M.P.),
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an observing program of the Association of Lunar and Planetary Observers
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(A.L.P.O.)
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Edited by: J.D. Beish
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INTRODUCTION
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The International Mars Patrol (IMP) is a cooperative program by planetary
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observers located around the Earth, that makes possible a 24-hour surveillance
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of all Martian longitudes. The IMP was organized during the early 1960's by
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the late Charles F. Capen and cataloged nearly 20,000 visual observations,
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more than 3,000 black & white and color photographs, and thousands of Martian
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surface measurements contributed by amateur and professional planetary astro-
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nomers.
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The Association of Lunar and Planetary Observers (A.L.P.O.) is an international
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group of students of the Sun, the Moon, the major planets, minor planets, me-
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teors, and comets. Our goals are to stimulate, coordinate, and generally pro-
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mote the study of these bodies using methods and instruments that are available
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to amateur astronomers. Observations carried out by professionals or with pro-
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fessional equipment are also welcome. We provide a service for the advanced
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amateur specializing in particular investigations, for the novice who wishes to
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develop techniques and general knowledge, and for the professional scientist
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interested in group studies and systematic patrols of our Solar System neigh-
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bors. All interested persons are welcome as members. Our activities are on a
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volunteer basis and each member can do as much or as little as she or he wish-
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es. Of course, the A.L.P.O. gains in stature in proportion to how much and
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also how well each member contributes.
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The Mars Section Recorders coordinate and instruct the cooperating observers
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in using similar visual, photographic, photometric,and micrometric techniques
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employing color filters and standard methods for reporting their observations
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which results in homogeneous sets of observing data that have good analytic
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value. Each apparition the Mars Section receives thousands of individual
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observations of visual drawings made with the aid of color filters, black-&-
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white and color photographs, intensity estimates of light and dark albedo
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features, color contrast estimates, and micrometer measurements of polar caps,
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cloud boundaries, and variable surface features during the 10 to 12 month obs-
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erving period. The chronological filing of this large quantity of data requires
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the observation information obtained for each night Universal Date be recorded
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on one or two standard observing report forms!
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It is with this regard that a simple, efficient and standard Mars Observing
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Report Form has been prepared by the Mars Recorders. This Standard Form can be
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used for reporting all types of observations such as; micrometry, transit tim-
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ings, intensity estimates, etc. Photographs may also be attached to the top
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or back of the forms and the relevant information blanks to be filled in at the
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telescope. Planetary aspects blanks can be filled in at other times than while
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observing.
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The A.L.P.O. was founded in 1947, by Walter H. Haas, and now enrolls over 700
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members, of which about 160 live in foreign countries on six continents. Our
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group is organized into Observing Sections that study each Solar System body or
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type of body.
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We have held conventions every year beginning in 1956, usually together with
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the meetings of the Astronomical League or of the Western Amateur Astronomers.
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Our chief means of communication is our quarterly Journal ("The Strolling As-
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tronomer"), although several of our Observing Sections also publish their own
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newsletters and handouts.
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Membership dues in the A.L.P.O. include a subscription to our Journal and are
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$14.00 per year for members in the United States, Canada, and Mexico; and
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$16.00 per year for other countries. (2-year rates are $24.00 and $29.00 re-
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spectively.) Payment should be by check or money order payable to "A.L.P.O."
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If our organization sounds of possible interest to you, write to:
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Harry D. Jamieson, A.L.P.O. Membership Secretary,
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P.O. Box 143, Heber Springs, Arkansas 72543.
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***IDENTIFYING A MARTIAN DUST STORM***
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Although immense global dust storms are firmly entrenched in Martian lore,
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they may be rare. Lowell Observatory's Leonard Martin has written that there
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have been only five well-documented "planet-encircling" Martian storms. These
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storms occurred in 1956, 1971, 1973, and two storms in 1977 (these were dis-
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covered by Viking Spacecraft). However, smaller dust storms or dust clouds
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are observed on Mars. These dust clouds are very difficult to identify in
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their beginning stages and, in some cases, go undetected even after they have
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fully developed.
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Numerous reports of yellowish hazes have appeared in the literature and in the
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International Mars Patrol archives. Mars observers frequently report "albedo
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features" lacking in contrast, the planet is "washed out," or Mars' atmosphere
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is "dusty." These terms have been employed in the past by the A.L.P.O. Mars
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Recorders. While such descriptions may have merit, generalized yellow hazes
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and temporary losses in surface contrast is usually omitted in our reports.
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Photographic evidence for these phenomena is also weak, since the proper sen-
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sitometric calibration is usually lacking.
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While working with Leonard Martin (Planetary Research Center, Lowell Observa-
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tory, Flagstaff, Arizona) and Richard W. Zurek (JPL) on problems of correctly
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identifying and classifying Martian dust clouds or storms, new guidelines have
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been established by the A.L.P.O. Mars Recorders for interpreting Martian dust
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clouds and dust storms, they are classified as:
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I. Type of Observation.
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1. White cloud or bright area mistaken for dust cloud.
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2. Visual observation(s) of dust clouds in a dust storm.
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3. Instrumental observation(s) of dust cloud/storm (Includes
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photographic, polarimetric, spacecraft data, or other data
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obtained by instrumental means).
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Table I (con't)
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II. Martian dust clouds.
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1. Obscuration -- Not sure if surface or atmospheric.
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2. Dust Haze -- Partial obscuration with displacement.
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3. Bright dust cloud -- Bright obscuration with displacements.
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4. Limb projection/terminator protrusion by dust cloud.
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III. Martian dust storms.
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1. Local -- Dust storm with major axis not to exceed 2000 km
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(1,243 miles or less than 34 degrees).
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2. Regional -- Dust storm with major axis that exceeds 2000 km
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(1,243 miles or less than 34 degrees) but not encircling either
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or both hemispheres.
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3. Planet Encircling -- Dust storm with major axis that completely
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encircles either one or both hemispheres of Mars.
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Confusion over the colors of Mars is nothing new. When the bright planet Mars
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is observed against a nighttime sky, the planet's predominantly orange colored
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surface becomes highly saturated to the eye. The darker albedo features, when
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observed against this saturated background are perceived as complementary hues.
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This effect is known as "simultaneous contrast" and is explained the May 1989
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Sky and Telescope Magazine, Vol. 77, No. 5, page 474, inset "Mars from Mauna
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Kea" in an article by W.K. Hartmann, "What's New on Mars?".
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COLOR FILTERS
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A full set of photo-visual color filters is a most important observing aid the
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planetary astronomer can have in his or her arsenal of telescopic accessories.
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Color filters help overcome image deterioration caused by atmospheric scatter-
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ing of light, permit separation of light from different levels in a planetary
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atmosphere, increase hue contrast between areas of differing color, and reduce
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irradiation within the observer's eye. All of these factors increase the
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sharpness of surface and cloud details that are seen on the planet Mars.
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Using color filters at the telescope can be a most challenging an rewarding ex-
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perience, although several weeks of practice may be necessary to condition the
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observer to detect those subtle wisps of clouds and hazes often observed in the
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Martian atmosphere. Without the aid of these filters, many interesting phenom-
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ena may go undetected.
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Table I. Eastman Kodak Wratten Color Filters used for visual and
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photographic observations of Mars. Transmission Characteristics
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are given.
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RED (W25,29) -- Gives maximum contrast of surface features, polar
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cap edges, enhances fine surface details, and dust cloud bound-
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aries.
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ORANGE (W21,23A) -- Further increases contrast between light and
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dark features, penetrates hazes and most clouds, and brightens
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dust clouds.
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Table I (con't)
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YELLOW (W8,12,15) -- Brightens desert regions, darkens blue and
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brown features.
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GREEN (W56,57) -- Darkens red and blue features, enhances frost
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patches, surface fogs, polar projections,and polar cap boundaries.
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BLUE-GREEN (W64) -- Enhances ground fogs, limb and polar hazes.
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BLUE (W80A,38A)-- Shows atmospheric clouds, discrete white clouds,
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and limb hazes, and darkens reddish features, which probably con-
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tributes to the illusion of blue or violet haze.
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VIOLET (W47) -- Shows blue and blue-white clouds,limb hazes,equa-
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torial cloud bands, polar cloud hoods, and dark dust clouds,and
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aids in the detection of the Violet Clearing phenomenon.
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MAGENTA (W30,32) -- Enhances red and blue features, darkens green
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features.
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THE MARS RECORDERS
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To participate in our Mars observing program, receive the Martian Chronicle, an
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observing form (to copy as many times as required) -- please send 8 Self Ad-
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dressed Stamped Envelopes to the individual listed below that corresponds to
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your local area. Each of the following ALPO Mars Recorders will be responsible
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for receiving and corresponding with observers in a specific geographic area:
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Jeff D. Beish, 9460 Toni Drive, Miami, Florida 33157 (CompuServe 72317,3306)
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-- Alabama, Arkansas, Florida, Georgia, Hawaii, Kentucky, Mississippi, North
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Carolina, South Carolina, Tennessee, and Virginia.
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Harry Cralle, 3902 E. 29th Street (J-4), Bryan, Texas 77802
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-- Arizona, California, Colorado, Kansas, Louisiana, Missouri, Nevada, New
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Mexico, Oklahoma, Texas, Utah, and Wyoming.
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Carlos Hernandez, 2714 Plaza Drive, Woodbridge, New Jersey 07095
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-- Alaska, Connecticut, D.C., Delaware, Massachusetts, Maryland, Maine, New
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Hampshire, New York, New Jersey, Pennsylvanian, Road Island, and Vermont.
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Don C. Parker, Coral Gables, Florida 33156 (CompuServe 72317,3157)
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-- Overseas and U.S. Territories.
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Dan Troiani, 629 Verona Ct., Schaumburg, Illinois 60193
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-- Idaho, Illinois, Indiana,Iowa, Michigan, Minnesota, Montana, Nebraska, North
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Dakota, Ohio, Oregon, South Dakota, Washington, West Virginia, and Wisconsin.
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CALENDAR OF EVENTS -- MARS, 1990-91
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03/06/90 -- Martian Southern Spring Equinox. South Polar Cap (SPC) should be
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near maximum diameter. Is South Polar Hood (SPH) present? Look for North Polar
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Hood. Disk diameter only 4.9 arcseconds ("). Mars rises approx. 2.5 hours
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before Sun.
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04/01/90 -- Disk diameter 5.4". Mars rises over 3 hours before Sun. Can the
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major albedo features be seen? SPC large and bright. Is the eastern border of
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Syrtis Major withdrawing? In violet light are orographic clouds present over
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Tharsis-Amazonis? April Fool's Day!
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04/27/90 -- Disk diameter 6". SPC rifts developing. Watch for those Martian
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dust clouds (red filter), orographics clouds (violet filter).
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05/12/90 -- Novissima Thyle appears as a bright SPC projection. However disk
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diameter still small.
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05/21/90 -- Southern hemisphere mid-spring. Any dust clouds yet? Orographics
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over the Tharsis volcanoes -- W-Cloud? Maximum earthward tilt of Martian South
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pole for this apparition, affording good views of SPC. Has Novissima Thyle sep-
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arated from SPC to become Mountains of Mitchel? At disk diameter of 6.6" are
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the Rima Australis and Magna Depressio visible in SPC?
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06/05/90 -- Disk diameter is now 7". Rapid SPC retreat. Quality micrometer me-
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asurements of SPC possible.
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06/29/90 -- Mars at perihelion (closest to Sun). Disk diameter now 7.8". Views
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of surface details better. Rapid SPC retreat. W-clouds possible. Dust clouds?
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Is Novus Mons (Mts. of Mitchel) detached from SPC?
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07/15/90 -- Late Southern spring. SPC now more than 20 degrees diameter. Watch
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for dust clouds (red filter!). Numerous white patches possible on surface.
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07/30/90 -- Martian Southern Summer Solstice. SPC continues to retreat poleward
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Disk diameter 9".
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08/16/90 -- Disk diameter is now 10". Some photography now possible. Discrete
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(white) clouds and white areas should be minimal. SPC small, offset from pole.
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09/01/90 -- SPC retreat slowing--stable polar remnant. Is Syrtis Major narrow?
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Blunted? Possibility of dust storms again increasing. Large northern winter
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North Polar Hood (NPH) should be prominent. Measure latitude of NPH -- does it
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retreat or disappear when dust storm present?
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09/14/90 -- Disk diameter 12". Begin high resolution visual observations and
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high quality photography begins.
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10/17/90 -- High probability of dust storms. Disk diameter 15.4". Tilt of Mars
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now affording good view of both polar regions: large NPH. Look for tiny SPC
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remnant near South limb. SPC offset, so easier to see when CM near 30 degrees.
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Is SPC remnant present in mid-summer?
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CALENDAR OF EVENTS -- MARS, 1990-91 (con't)
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11/09/90 -- Continued alert for dust storms. SPC remnant visible? Antarctic
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hazes present? Is NPH variable, occasionally bright? (Use a violet filter for
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NPH measurements, observations.)
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11/20/90 -- Closest approach (0400 UT) to Earth. Disk diameter 18.1".
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11/27/90 -- Opposition (2028 UT). Disk diameter 17.9". Late Southern summer: Is
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SPC remnant still present. Photographs needed of SPC. NPH still observable.
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Watch for signs of NPH thinning. Are South polar hazes present?
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12/17/90 -- Disk diameter 16". NPH should be easily visible if present. Close-
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ly monitor hood from now on. When does it disappear and the NPC appear? Is SPC
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remnant still present? Any evidence of SPH? Watch Syrtis Major for signs of
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expansion to east.
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01/05/91 -- Southern hemisphere autumnal equinox. Carefully monitor antarctic
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region for evidence of SPC remnant and/or hazes. Will SPH form? N. hemisphere
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vernal equinox. Monitor arctic closely for date of disappearance of NPH. Watch
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for possible reformation of polar hood. NPC at maximum extent with edge near 55
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degrees areocentric latitude. Disk diameter 13.2". Begin micrometer/reticle NPC
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measurements, using red/orange filters.
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02/01/91 -- Disk diameter 10". Photography difficult but visual observations
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and NPC measurements still possible. Monitor antarctic for SPC remnant, hazes.
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Are Hellas, Argyre brightening?
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02/24/91 -- Disk diameter rapidly shrinking--now 8". Early Northern hemisphere
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spring. Continue NPC measurements. Is North Cap fairly static or entering rapid
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retreat phase? South polar regions becoming difficult to observe. Any signs
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of SPH?
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3/14/91 -- Disk diameter 7". Limb clouds/hazes should start to increase. Look
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for them in violet light. What is size, shape of Syrtis Major?
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04/04/91 -- Disk diameter 6". N. hemisphere mid-spring. Is NPC beginning rapid
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retreat? Are limb arcs increasing in frequency, intensity. Use filters! Ant-
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arctic hazes, hood? Cloud activity increases.
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For complete details for the physical and geocentric positions of Mars send for
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the "A.L.P.O. Solar System Ephemeris," $6.00 in the U.S, Canada, and Mexico;
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$8.50 in other countries. Write to: John E. Westfall, A.L.P.O. Director/Editor,
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P.O. Box 16131, San Francisco, CA 94116.
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*********************************************************************
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* -------->>> THE U.F.O. BBS - http://www.ufobbs.com/ufo <<<------- *
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********************************************************************* |