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                    T h e   M a r t i a n   C h r o n i c l e
August 1990                                                              No. 4
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     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
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                         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.                                      * 
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                     *** 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.




































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* Again, we must ca