PART 4





******************************************************************************
T h e M a r t i a n C h r o n i c l e
August 1990 No. 4 ******************************************************************************
The electronic newsletter by the International Mars Patrol (I.M.P.),
an observing program of the Association of Lunar and Planetary Observers
(A.L.P.O.)
Edited by: J.D. Beish ------------------------------------------------------------------------------

Is Mars' South Polar Missing?

Several observers have reported the disappearance of the Martian south polar cap (SPC). Because southern summer began on July 30th. the SPC was in rapid retreat during August and should not be very large. For those of us in the United States, observing Mars' during mid-August (Central Meridians (CM) from 150 - 270 degrees) the south limb will resemble a great "bald spot" where the SPC should be. The cap will be very hard to see for Northern Hemisphere observers because the cap is offset 7 degrees from the pole towards 30 degrees longitude. Therefore, the SPC is on the other side of the planet from us. From mid-August, the planetocentric declination of Earth (De) will be -11.2 deg. and decrease to -3.9 deg. by the end of September. This will also place the south polar region of Mars in a difficult position to observe for every one.
The two polar caps of Mars are composed differently. The north cap is a water ice cap covered with layers of carbon dioxide ice. While water has been detected in the south cap, it is mostly carbon dioxide. Because the atmos pheric pressure of Mars is too low for liquid water to exist on its surface, frozen materials in the caps do not melt but sublimate at temperatures above zero.

Mars looks strange?

Are we seeing new dark features on Mars or just changing shadows? Those who regularly observe the Moon know that shadows cast by Lunar surface fea tures change its surface appearance from day to day. Although certain Martian surface features are known to physically change in shape and darkness, shadows also effect the appearance of the Red Planet's surface. Shadows have a direct effect on the appearance of regions such as Tharsis -- with its steep rise from a large valley floor to its 12 and 16 mile high volcanoes -- or Hellas, which is shaped like a very large and deep crater. Remember also that shadows are longer near the planet's morning and evening limbs or terminator and are shorter nearest to the planet's noon hour (sub-solar point). In August, Mars' south pole is tilted toward the Sun, so, the shadows will appear to point in a more northerly direction. As the Martian seasons change from summer to au tumn, these same shadows will change directions as well, giving its surface a slightly different appearance.
However, don't let the shadows fool you, report all changes on the Mar tian surface to the ALPO Mars Recorders as soon as possible.


******************************** DUST STORMS ********************************* * * * Again, we must caution observers not to confuse those Martian white clouds * * or bright white surface deposits with dust clouds.We have received several * * calls and letters this month from observers claiming to have seen a large * * dust storm on Mars. While observing both visually and with sensitive CCD * * cameras, the ALPO Mars Recorders can find no trace of dust either on the * * Martian surface or in its atmosphere as of August 27, 1990. Remember, dust * * clouds are very bright in red light and they usually move about covering * * over portions of the Martian surface. * ******************************************************************************

*** GUIDELINES FOR IMP OBSERVERS ***

1. ALPO MEMBERSHIP: Membership in Association of Lunar and Planetary Observ ers (ALPO) is not mandatory for the IMP. However, we strongly urge our observ ers to join, if for no other reason than they can see the fruits of their labor in print in the apparition reports and other papers in The Strolling Astronomer. Subscribing to the J.A.L.P.O. also gives one the opportunity to read about others' observational techniques and methods of data reduction. In addition, the observer may find other fields which stimulate his interest, such as observing Pluto. U.S., Canada, and Mexico, send $14 for one year or $24 for two years to Harry D. Jamieson, P.O. Box 143, Heber Springs, Arkansas, 72543. Other countries: $16 for one year, $29 for two.

2. CORRESPONDENCE: All correspondence should contain an enclosed S.A.S.E. Remember that the A.L.P.O. staff is voluntary -- both with time and money!


OBSERVING AIDS

************************** MARS OBSERVER'S HANDBOOK ************************** * * * Now available from the Astronomical League is the Mars Observer's Handbook * * by Jeffrey D. Beish and Charles F. Capen at a new low price of $8.00. This * * very important and informative book is in second printing due to popular * * demand. Formerly published for The Planetary Society's Mars Watch '88, the * * book was sold out and has been out of print for the past two years. Send * * $8.00, check or money order to: Astronomical League Sales, Four Klopfer * * Street, Pittsburgh, PA 15209. * * * ******************************************************************************

a) The A.L.P.O. Solar System Ephemeris: 1990. This contains the complete ephemerides for the Sun, Moon, planets and minor planets as well as selected comets. This is a "must" if one is to get full enjoyment from his observing. Send $6.00 to A.L.P.O., P.O. Box 16131, San Francisco, CA 94116.

b) Introduction to Observing and Photographing the Solar System, by T.A. Dobbins, D.C. Parker, and C.F. Capen. Contains both theoretical and observa tional information on Solar System objects. Very detailed chapters on Mars, astrophotography, micrometry, etc. Forward by A.L.P.O. founder Walter H. Haas. Hardcover, $19.95 from Willmann-Bell, Inc., P.O. Box 35025, Richmond, VA 23235, (804) 320-7016.

c) IMP Astronomical Calculator (IMPAC). Computer program containing complete ephemerides of Mars and Jupiter for any year and geographical location. Also rise and set times, altitude, azimuths for all Solar System objects for observer's location. Automatic correction for Daylight Time, lunar phases for star party planning, telescope and mirror cell design, and comprehensive astrophotography program. Subroutines for color filter calculations and auto matic computation of Martian polar cap and Jovian belt latitudes from observer's input. For IBM XT, AT and compatibles, monochrome, EGA, or VGA. For a 5.25-inch diskette, send $49.95 to J.D. Beish, 9460 Toni Dr., Miami, FL 33157.

THE A.L.P.O. MARS SECTION -- 1990

ALPO Mars Recorders have been assigned to a geographical area. Observers should correspond with the recorder in his or her area:

JEFF BEISH, 9460 Toni Dr., Miami, Fl, 33157: AL, AR, FL, GA, HA, KY, MS, NC, SC, TN, and VA.

HARRY CRALLE, 3902 E. 29th St. (J-4), Bryan, Texas, 77802: AZ, CA, CO, KS, LA, MO, NV, NM, OK, TX, UT, and WY.

CARLOS HERNANDEZ, 2714 Plaza Dr., Woodbridge, NJ, 07095: AK, CT, DC, DE, MA, MD, ME, NH, NJ, NY, PA, RI, and VT.

DON PARKER, 12911 Lerida St., Coral Gables, FL, 33156: U.S. Territories and Possessions and all areas outside U.S.

DAN TROIANI, 629 Verona Ct., Schaumberg, IL, 60193: IA, ID, IL, IN, MI, MN, MT, ND, NE, OH, OR, SD, WA, WI, WV.

Jerry
telnet://ricksbbs.synchro.net:23
http://ricksbbs.synchro.net:8080
---
þ Synchronet þ Rick's BBS - telnet://ricksbbs.synchro.net:23

PART 5





****************************************************************************** * T h e M a r t i a n C h r o n i c l e * * October 1990 No. 5 * ******************************************************************************
The electronic newsletter by the International Mars Patrol (I.M.P.),
an observing program of the Association of Lunar and Planetary Observers
(A.L.P.O.)
Edited by: J.D. Beish ------------------------------------------------------------------------------ ************************** MARS OBSERVER'S HANDBOOK ************************** * * * Now available from the Astronomical League is the Mars Observer's Handbook * * by Jeffrey D. Beish and Charles F. Capen at a new low price of $8.00. This * * very important and informative book is in second printing due to popular * * demand. Formerly published for The Planetary Society's Mars Watch '88, the * * book was sold out and has been out of print for the past two years. Send * * $8.00, check or money order to: Astronomical League Sales, Four Klopfer * * Street, Pittsburgh, PA 15209. * * * ******************************************************************************

Sand Ships of Mars

Among one of the most exciting moments in a Mars observer's life is to catch a dust storm on Mars on the move. It is rare indeed when one can watch one of these great red clouds slowly move over the Martian landscape covering over features that were dark and well defined just hours before.
While no two dust clouds are alike they nevertheless exhibit similar characteristics. Dust clouds are frequently confused with bright white areas, frosts, or localized fogs, and some dense white clouds. In addition, after identification is made, it becomes difficult to distinguish active dust clouds from fresh surface dust deposits. Such misinterpretation can make time studies difficult.
A careful diagnosis of observational records of Mars from 1877 through the seventeen perihelic apparitions since 1907 show evidence that Martian dust storms have evolved in preferred southern locations near the latitude of maximum insolation. Maximum insolation occurs during Martian southern summer which corresponds to the terrestrial months of August, September, and October of perihelic apparitions (Capen and Martin, 1972). Recent studies of Martian dust storms reveal three periods in the Martian year when dust clouds and/or storms are most likely to occur. These periods correspond to 105 dg Ls* (northern summer), 255 dg Ls (southern spring), and 315 dg Ls (southern summer). [Beish and Parker, 1990]. * NOTE: Ls is the Planetocentric Longitude of the Sun.
Since 1971, the year of the "Great Dust Storm of Mars," the ALPO Mars Recorders have suspected that these disturbances come in pairs. We have seen that in 1971 a major dust storm occurred on 213 dg Ls, followed by a "planet encircling" dust storm on 260 dg Ls. Again, in 1973 a major storm began on 244 dg Ls and was followed by a "planet encircling" storm on 300 dg Ls. The Viking Lander recorded two "planet encircling" storms on 204 and 268 dg Ls. Although the two dust storms of 1988 did not reach the "planet encircling" stage, similar patterns emerged; during 206 dg Ls a major storm occurred, followed by another major storm on 313 dg Ls.
Perhaps the statistical significance of the three periods above appear to mislead us when attempting to predict when these disturbances should occur. However, one should be especially alert when observing Mars during these times -- even though we have passed through the first sensitive period, be watchful in the next few weeks, alas, a major dust storm may be lurking just around the corner!


REPORTING MARTIAN DUST CLOUDS AND STORMS

In analyzing the IMP data, the ALPO Mars Recorders have had to exercise considerable caution in defining dust clouds. They have applied the following criteria:

1. The sine qua non of Martian dust clouds is movement with obscura- tion of previously well-defined albedo features. Absence of this criterion in the present study disqualified a candidate from inclusion under dust clouds [Beish, et al, 1990].

2. They are bright in red light. Repeat -- bright in red light!

3. Often, when these clouds reach heights of several kilometers, they may cast shadows -- that are observable from Earth. There are numerous reports of anomalous transient dark surface markings appearing near dust clouds, espe- cially when the solar phase angle was reasonably large [Slipher, 1962].



A DUST CLOUD IN OCTOBER 1990

During the first week of October 1990 the phone at ALPO's International Mars Patrol headquarters began to ring. News of bright spots on Mars, "maybe a dust cloud or something," scoffed the cautious observers. Their words were restrained and with good reason -- past experience has taught them not to jump to conclusions, especially about this Martian dust storm business. After all, these storms are very rare and often mislead the most experienced Martian dust storm watchers!
The genesis of the latest disturbance began on September 25, 1990. Re- porting from Paragould, Arkansas, Kermit Rhea noted that Chryse appeared brighter than usual from the 25th. of September through October 2nd. His observations indicate unusual activity in the regions of Chryse and Xanthe.
Don Parker, fearful of awaking my family, avoided calling me while he observed Mars at 0400 UT on October 4th (310 dg Ls), suspected that the bright streak bordering northern Aromatum Promontorium in the south of Chryse might be the beginning of a dust storm. The following night (310.5 dg Ls) this Mars Recorder watched with delight as the dust cloud, correctly identi- fied by Parker the night before, had moved southwest onto Eos, partially obscuring Aurorae Sinus with what appeared as a bright oval spot followed by a long streak. The morning side of Mars had lost its usual effect of limb darkening and was replaced by a bright haze extending 10 degrees into its morning. Subsequent visual reports and photographs show that a dust cloud extended from eastern Margaritifer Sinus (30W, 0N) to just south of Aurorae Sinus.
October 6th. (311 dg Ls) brought more meteorological delights, white clouds now laced much of the morning limb and portions of Chryse, even a bright white cloud was seen on the limb just to the north of Sabaeus Sinus. Morning hazes were even brighter, extending 15 to 20 degrees away from the limb. The dust cloud of October 5th. had moved 575 miles further southwest, now obscuring the southern half of Aurorae Sinus and completely covered Eos (40W, 12S). A dull streak or "dusty trail" was observed to extend from the southeast of Aurorae Sinus over into Ophir -- one of the brightest areas on the planet Mars.
Observers on October 7th. (311.8 dg Ls) reported an increase in meteorol- ogy on Mars. Clouds had formed over Deucalionis Regio, Aram, and in the crea- tor Eros. Several discrete clouds in Chryse mixing with white morning limb clouds and hazes. The main dust cloud had moved west-southwest anther 475 miles to 50W, 20S). A peculiar Y-shaped dust cloud hung over Aurorae Sinus extending into Ophir as if transferring dust particles in that region from the main disturbance.
One asks what would have crossed Ray Bradbury's mind while viewing such splendor -- might he think it was Martians on the run in their sand ships?
At last, the next day the small Martian dust storm appeared to be over. With perfect on October 8th. (312 dg Ls), this Mars observer saw a familiar Martian landscape, with only a few alterations to the usually dark and well defined Aurorae Sinus. Eos appeared to have grown a little. As expected, a dull dusty haze covered the south polar region and the morning limb was bright with blue and reddish hazes [Beish et al, 1984].
Oh yes, all was quite again on Barzoom, lest we not forget Edgar Rice Burroughs.


CONCLUSION

Although the October 4th. - 7th. dust disturbance is not considered a major storm it was a significant meteorological activity. Moving over 1,000 miles of the Martian landscape it did alter small portions of previously dark and well defined features. A secondary dust cloud appeared in Ophir, an area over 650 miles west of the main dust cloud, on October 7th. We can theorize that dust clouds on Mars may erupt in more than one place if the conditions are right. Past observations of Martian dust storms indicate that the Red Planet was very near its peak dust storm period at 315 dg Ls. [Beish et al, 1990]. Remember, 315 dg Ls will fall on October 18, 1990!

REFERENCES

Beish, J.D., and D.C. Parker, "Meteorological Survey of Mars, 1968-1985," Journal of Geophysical Research, Vol. 95, B9, August 20, 1990.

Beish, J.D., Parker, D.C., and Capen, C.F., "A Major Martian Dust Storm in 1984", J.A.L.P.O., Vol. 30, Nos. 9-10, August 1984.

Capen, C.F., and L.J. Martin,"Survey of Martian Yellow Storms." Bull. Amer. Astron. Soc. 4, 374, 1972.

Capen, C.F., "A Martian Yellow Cloud - July 1971." Icarus, 22, 345-362, 1974.

Slipher, E.C., "Mars, The Photographic Study. Northland Press, Flagstaff, AZ, 108-109, 1962.


******** Introduction to Observing and Photographing the Solar System ******** * * * Picked as one of the top twelve non-technical astronomy books of 1989 by * * the ASP, Introduction to Observing and Photographing the Solar System, * * by T.A. Dobbins, D.C. Parker, and C.F. Capen contains both theoretical and * * observational information on Solar System objects. Very detailed chapters * * on Mars, astrophotography, micrometry, etc. Forward by A.L.P.O. founder * * Walter H. Haas. Hardcover, $19.95 from Willmann-Bell, Inc., P.O. Box 35025 * * Richmond, VA 23235, (804) 320-7016. * * * ******************************************************************************

Jerry
telnet://ricksbbs.synchro.net:23
http://ricksbbs.synchro.net:8080
---
þ Synchronet þ Rick's BBS - telnet://ricksbbs.synchro.net:23

PART 6






******************************************************************************
T h e M a r t i a n C h r o n i c l e
November 1990 No. 6 ******************************************************************************
The electronic newsletter by the International Mars Patrol (I.M.P.),
an observing program of the Association of Lunar and Planetary Observers
(A.L.P.O.)
Edited by: J.D. Beish ------------------------------------------------------------------------------

A DUST CLOUD IN NOVEMBER 1990

While using the University of Hawaii's 24-inch at Mauna Kea Observatory, Beish received a call from Don Parker with an alert of yet another dust storm. Beish was there during 30 October through 7 November 1990 photographing Mars for Lowell Observatory's International Planetary Patrol. On 4 and 5 November he recorded in color three dust clouds moving across the Aurorae Sinus-Solis Lacus regions.


METEOROLOGY OF MARS IN 1990

The ALPO/IMP has over 20,000 observations of Mars and many of the late Chick Capen's scientific papers covering his meteorological studies of the Red Planet. Results of Capen's work and more recent studies by the IMP, Beish and Parker published "Meteorological Survey of Mars, 1968-1984" in the Journal of Geophysical Research, (95, B9, August 20, 1990) that can be used to predict the times when clouds, hazes, and other atmospheric phenomena are most likely to occur on Mars.
As we draw nearer to closest approach (20 NOV 04UT) and opposition (27 NOV 21UT) the orbit of Mars will pass through 336 degrees and 340 degrees Planetocentric Longitude of the Sun (Ls), respectively. These periods corre- spond to late Martian southern summer and observers should begin to see an increase in cloudiness on Mars. Already clouds have been seen forming in the evening in Libya, an area just east of Syrtis Major.
Approaching local Martian noon, discrete white orographic clouds, identi- fied as water clouds by the Mariner 9 spacecraft, are seen in Martian spring and summer forming on the upper slopes of the large volcanoes (Olympus Mons [113W, 18N], Ascraeus Mons [104W, 11N], Pavonis Mons [112W, 00], Arsia Mons [120W, 09S], and Elysium Mons [212W, 25N]), and between Tharsis Tholus and Valles Marineris (80-100, 04N). These seasonal clouds ("W-clouds") were well observed during northern Summer (120 - 160 Ls) in 1984 and in 1986 after rapid thawing of the North Polar Cap (NPC) began (204-209 Ls). In the future, it will be interesting to learn if these orographic clouds occur twice each Martian year, because they originate in the equatorial region of the planet. Look for them after the large southern basins, Hellas and Argyre, have lost their whiteness and have returned to a dark-ocher hue, and during the rapid retreat of the South Polar Cap (SPC) from southern mid-Spring until Summer (235- 270 Ls). Because of the observed appearance and seasonal behavior of the great southern basins, the authors suspect that they act as "cold traps" during Mars' southern Autumn and Winter, thus controlling the water vapor in that hemisphere. Because orographic clouds are best seen through blue and violet filters, they are well-elevated and are probably generated by mechani- cal uplift, and growing by convection.
A faint veil of wispy white clouds with variable shapes and levels of opacity, known as the equatorial cloud band (ECB), is occasionally seen ex- tending across Mars' disk. Because the ECB is detected best in ultraviolet and violet light, it resides at a chilly high altitude, and is probably com- posed of Carbon Dioxide ice crystals. Because the ECB is equatorial, it too may occur twice each Martian year, appearing with the sublimation of each cap.

Limb haze appears as a bright misty arc of light on the sunrise or sunset limb of Mars, and is caused by the observer's oblique view through the equiva- lent of several Martian atmospheres of aerosols, which may consist of Carbon Dioxide ice crystals, fine dust, cirrus-type water clouds, or a mixture of these. Consequently, the observation of the global location, color, and densi- ty of limb haze is a very sensitive method of diagnosing the global system of Martian weather and unusual polar phenomena. Sometimes, the color and density of the hazes help to detect dust storms that have begun on the other side of the planet.
Limb haze may be seasonal or nonseasonal and, since it does not rotate with the planet, disappears around local 8 or 9 A.M., Mars time. It is best seen in violet light if at high altitudes, or in blue light if at mid-alti- tudes.
A most delicate and challenging feat of observation is the detection of volatiles at the boundary between the Martian atmosphere and its surface. In this volatile regime, ice-fogs and frosts, often called bright patches, can be distinguished from elevated clouds by means of comparing their relative brightnesses and boundary definitions as seen with the aid of blue, blue green, green, and yellow filters. If the suspect bright feature appears brighter in blue light than it does in green or yellow light, it is an atmos- pheric cloud. If it is brighter and better defined in blue-green light than in blue or yellow light, it is probably ice-fog contiguous to the surface. If the patch appears brighter with sharp boundary in green and yellow light and is not well seen in blue light, it can be identified as surface frost. A boundary-layer volatile's diurnal behavior and location also helps to distin- guish it from clouds and limb haze. Fogs and frosts form in the chill of the Martian night, rotate with the planet, dissipate in the morning sunlight, and usually disappear by local noon. Fogs normally form in valleys, in fossae (linear depressions), basins, and on upper slopes. Frosts are usually noted on cool, light albedo features, plana (plateaus), montes (mountains), and floors of large craters. Because these volatiles are topographically con- trolled the discovery of their locations and seasonal occurrence is most important to the study of Martian weather patterns and areography.


************************** MARS OBSERVER'S HANDBOOK ************************** * * * Now available from the Astronomical League is the Mars Observer's Handbook * * by Jeffrey D. Beish and Charles F. Capen at a new low price of $8.00. This * * very important and informative book is in second printing due to popular * * demand. Formerly published for The Planetary Society's Mars Watch '88, the * * book was sold out and has been out of print for the past two years. Send * * $8.00, check or money order to: Astronomical League Sales, Four Klopfer * * Street, Pittsburgh, PA 15209. * * * ******************************************************************************


******** Introduction to Observing and Photographing the Solar System ******** * * * Picked as one of the top twelve non-technical astronomy books of 1989 by * * the ASP, Introduction to Observing and Photographing the Solar System, * * by T.A. Dobbins, D.C. Parker, and C.F. Capen contains both theoretical and * * observational information on Solar System objects. Very detailed chapters * * on Mars, astrophotography, micrometry, etc. Forward by A.L.P.O. founder * * Walter H. Haas. Hardcover, $19.95 from Willmann-Bell, Inc., P.O. Box 35025 * * Richmond, VA 23235, (804) 320-7016. * * * ******************************************************************************

Jerry
telnet://ricksbbs.synchro.net:23
http://ricksbbs.synchro.net:8080
---
þ Synchronet þ Rick's BBS - telnet://ricksbbs.synchro.net:23