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                    T h e   M a r t i a n   C h r o n i c l e
April 1990                                                               No. 2
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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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                                INTRODUCTION

The  International  Mars Patrol (IMP) is a cooperative  program  by  planetary  
observers located around the Earth, that makes possible a 24-hour surveillance  
of  all Martian longitudes. The IMP was organized during the early  1960's  by  
the  late  Charles F. Capen and cataloged nearly 20,000  visual  observations,  
more than 3,000 black & white and color photographs, and thousands of  Martian  
surface measurements contributed by amateur and professional planetary  astro-
nomers.  

The Association of Lunar and Planetary Observers (A.L.P.O.) is an international
group of students of the  Sun,  the Moon, the major planets, minor planets, me-
teors, and comets.  Our goals are to stimulate,  coordinate, and generally pro-
mote the study of these bodies using methods and instruments that are available
to amateur astronomers.  Observations carried out by professionals or with pro-
fessional equipment are also welcome.   We provide a  service for the  advanced
amateur specializing in particular investigations, for the novice who wishes to
develop techniques  and general knowledge,  and for the  professional scientist
interested in  group studies and  systematic patrols of our Solar System neigh-
bors.  All interested persons are welcome as members.   Our activities are on a 
volunteer basis and each member can do as much or as little as she  or he wish-
es.  Of course,  the  A.L.P.O. gains in stature in  proportion to  how much and
also how well each member contributes.

The  Mars Section  Recorders coordinate and instruct the cooperating  observers
in using similar visual,  photographic, photometric,and micrometric  techniques
employing  color filters and standard methods for reporting their  observations
which  results in  homogeneous sets of observing data that have  good  analytic
value.   Each  apparition the  Mars Section  receives  thousands of  individual
observations  of visual drawings made with the aid of  color filters,  black-&-
white  and  color photographs,  intensity estimates of light  and  dark  albedo
features,  color contrast estimates, and micrometer measurements of polar caps,
cloud boundaries, and variable surface features during the  10 to 12 month obs-
erving period. The chronological filing of this large quantity of data requires
the observation information obtained for each night  Universal Date be recorded
on one or two standard observing report forms!

It is with this  regard that a simple,  efficient and  standard Mars  Observing
Report Form has been prepared by the Mars Recorders. This Standard Form  can be
used for reporting all types of observations such as;  micrometry, transit tim-
ings,  intensity estimates, etc.  Photographs may  also be  attached to the top
or back of the forms and the relevant information blanks to be filled in at the
telescope.  Planetary aspects blanks can be filled in at other times than while
observing.


The A.L.P.O. was founded in 1947,  by Walter H. Haas,  and now enrolls over 700
members,  of which about  160 live in foreign countries on six continents.  Our
group is organized into Observing Sections that study each Solar System body or
type of body.

We have held  conventions every year beginning in  1956,  usually together with
the meetings of the Astronomical League  or of the Western Amateur Astronomers.
Our chief means of  communication is our quarterly Journal  ("The Strolling As-
tronomer"),  although several of our Observing Sections  also publish their own
newsletters and handouts.

Membership dues in the  A.L.P.O. include a subscription to our Journal  and are
$14.00  per year for  members in the  United States,  Canada, and  Mexico;  and
$16.00  per year for other countries.  (2-year rates are  $24.00 and $29.00 re-
spectively.)  Payment should be by check or money order payable to "A.L.P.O."

     If our organization sounds of possible interest to you, write to:  
           Harry  D.  Jamieson,  A.L.P.O.  Membership  Secretary,
               P.O.  Box 143, Heber Springs,  Arkansas  72543.  
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                  ***IDENTIFYING A MARTIAN DUST STORM***

Although  immense  global  dust storms are firmly entrenched in  Martian  lore,
they may be rare.  Lowell Observatory's Leonard Martin  has written that  there
have been only five well-documented "planet-encircling" Martian storms.   These
storms  occurred in 1956, 1971, 1973, and two storms in 1977  (these were  dis-
covered  by Viking Spacecraft).   However, smaller dust storms or  dust  clouds
are  observed on  Mars.   These dust clouds are very difficult to  identify  in
their beginning stages and,  in some cases, go undetected even after they  have
fully developed.  

Numerous reports of yellowish hazes have appeared in the literature  and in the
International Mars Patrol archives.   Mars observers frequently report  "albedo
features" lacking in contrast, the planet is "washed out,"  or Mars' atmosphere
is "dusty."   These terms have been employed in the  past by the  A.L.P.O. Mars
Recorders.  While such  descriptions may have merit,  generalized yellow  hazes
and  temporary losses in  surface contrast is usually omitted in  our  reports.
Photographic  evidence for these phenomena is also weak,  since the proper sen-
sitometric calibration is usually lacking.

While working with  Leonard Martin (Planetary Research Center,  Lowell Observa-
tory, Flagstaff, Arizona)  and Richard W. Zurek (JPL)  on problems of correctly
identifying and classifying Martian dust clouds or storms,  new guidelines have
been established by the  A.L.P.O. Mars Recorders for interpreting  Martian dust
clouds and dust storms, they are classified as:

     I.  Type of Observation.

     	1. White cloud or bright area mistaken for dust cloud.
	2. Visual observation(s) of dust clouds in a dust storm.
	3. Instrumental observation(s) of dust cloud/storm (Includes
           photographic, polarimetric, spacecraft data, or other data 
           obtained by instrumental means).


     Table I (con't)
     
     II.  Martian dust clouds.

        1. Obscuration -- Not sure if surface or atmospheric.
	2. Dust Haze -- Partial obscuration with displacement.
	3. Bright dust cloud -- Bright obscuration with displacements.
	4. Limb projection/terminator protrusion by dust cloud.

     III. Martian dust storms.

	1. Local -- Dust storm with major axis not to exceed 2000 km
           (1,243 miles or less than 34 degrees).
	2. Regional -- Dust storm with major axis that exceeds 2000 km
           (1,243 miles or less than 34 degrees) but not encircling either
 	   or both hemispheres.
	3. Planet Encircling -- Dust storm with major axis that completely
           encircles either one or both hemispheres of Mars.


Confusion over the colors of Mars is nothing new.  When the bright planet  Mars
is observed against a nighttime sky,  the planet's predominantly orange colored
surface becomes highly saturated to the eye.  The darker albedo  features, when
observed against this saturated background are perceived as complementary hues.
This effect is known as "simultaneous contrast"  and is explained the  May 1989
Sky and Telescope Magazine,  Vol. 77, No. 5, page 474,  inset  "Mars from Mauna
Kea" in an article by W.K. Hartmann, "What's New on Mars?".

                            COLOR FILTERS

A full set of photo-visual  color filters is a most important observing aid the
planetary astronomer can have in his or her arsenal of telescopic  accessories.
Color filters help overcome image deterioration caused by  atmospheric scatter-
ing of light,  permit separation of light from  different levels in a planetary
atmosphere, increase hue contrast between areas of differing  color, and reduce
irradiation  within the observer's eye.  All  of  these  factors  increase  the
sharpness  of surface and cloud details that are  seen  on  the  planet Mars.

Using color filters at the telescope can be a most challenging an rewarding ex-
perience,  although several weeks of practice may be necessary to condition the
observer to detect those subtle wisps of clouds and hazes often observed in the 
Martian atmosphere.  Without the aid of these filters, many interesting phenom-
ena may go undetected.  
 
      Table I.  Eastman Kodak Wratten Color Filters used for visual and
      photographic  observations of Mars.  Transmission Characteristics
      are given.

      RED (W25,29) -- Gives maximum contrast of surface features, polar
      cap edges,  enhances fine surface details,  and dust cloud bound-
      aries.

      ORANGE (W21,23A) --  Further increases contrast between light and
      dark features,  penetrates hazes  and most clouds,  and brightens 
      dust clouds.

     Table I (con't)

      YELLOW (W8,12,15)  --  Brightens desert regions, darkens blue and 
      brown features.

      GREEN (W56,57)  --  Darkens red and blue features, enhances frost 
      patches, surface fogs, polar projections,and polar cap boundaries.

      BLUE-GREEN (W64) -- Enhances ground fogs, limb and polar hazes.

      BLUE (W80A,38A)-- Shows atmospheric clouds, discrete white clouds, 
      and limb hazes, and darkens reddish features,  which probably con-
      tributes to the illusion of blue or violet haze.

      VIOLET (W47) -- Shows blue and blue-white clouds,limb hazes,equa-
      torial cloud bands,  polar cloud hoods,  and dark dust clouds,and 
      aids in the detection of the Violet Clearing phenomenon. 

      MAGENTA (W30,32) -- Enhances red and blue features, darkens green
      features. 


                              THE MARS RECORDERS

To participate in our Mars observing program, receive the Martian Chronicle, an
observing form  (to copy as many times as required) -- please  send  8 Self Ad-
dressed Stamped Envelopes  to the individual listed below that   corresponds to 
your local area.  Each of the following ALPO Mars Recorders will be responsible 
for receiving and corresponding with observers in a specific  geographic area: 

Jeff D. Beish, 9460 Toni Drive, Miami, Florida 33157    (CompuServe 72317,3306)
-- Alabama, Arkansas, Florida, Georgia,  Hawaii, Kentucky,  Mississippi,  North 
Carolina, South Carolina, Tennessee, and Virginia.  

Harry  Cralle, 3902 E. 29th Street (J-4), Bryan, Texas  77802
--  Arizona,  California, Colorado,  Kansas, Louisiana,  Missouri, Nevada, New
Mexico, Oklahoma, Texas, Utah, and Wyoming.  

Carlos Hernandez, 2714 Plaza Drive, Woodbridge, New Jersey  07095 
--  Alaska,  Connecticut,  D.C., Delaware, Massachusetts, Maryland, Maine, New 
Hampshire, New York, New Jersey, Pennsylvanian, Road Island, and Vermont.  

Don C. Parker, Coral Gables, Florida 33156             (CompuServe 72317,3157)
--  Overseas and U.S. Territories.  

Dan Troiani, 629 Verona Ct., Schaumburg, Illinois 60193 
-- Idaho, Illinois, Indiana,Iowa, Michigan, Minnesota, Montana, Nebraska, North
Dakota, Ohio, Oregon, South Dakota,  Washington, West Virginia, and Wisconsin.






                     CALENDAR OF EVENTS -- MARS, 1990-91

03/06/90 -- Martian  Southern Spring Equinox.  South Polar Cap (SPC)  should be 
near maximum diameter. Is South Polar Hood (SPH) present?  Look for North Polar 
Hood.   Disk diameter only  4.9 arcseconds (").  Mars rises approx.  2.5  hours 
before Sun.

04/01/90 -- Disk diameter 5.4".  Mars rises over  3 hours before Sun.  Can  the
major albedo features be seen?  SPC large and bright.  Is the eastern border of 
Syrtis Major withdrawing?  In violet light are  orographic clouds  present over
Tharsis-Amazonis?  April Fool's Day!

04/27/90 -- Disk diameter 6".   SPC rifts developing.  Watch for those  Martian
dust clouds (red filter), orographics clouds (violet filter).

05/12/90 -- Novissima Thyle appears as a bright  SPC projection.   However disk
diameter still small.

05/21/90 -- Southern hemisphere mid-spring.  Any dust clouds yet?   Orographics
over the Tharsis volcanoes -- W-Cloud?  Maximum earthward tilt of Martian South 
pole for this apparition, affording good views of SPC. Has Novissima Thyle sep-
arated from  SPC to become Mountains of Mitchel?  At disk diameter of  6.6" are 
the Rima Australis and Magna Depressio visible in SPC?

06/05/90  -- Disk diameter is now 7". Rapid SPC retreat. Quality micrometer me-
asurements of SPC possible.

06/29/90 -- Mars at perihelion (closest to Sun).  Disk diameter now 7.8". Views
of surface details better.  Rapid SPC retreat. W-clouds possible.  Dust clouds? 
Is Novus Mons (Mts. of Mitchel) detached from SPC?

07/15/90 -- Late Southern spring.  SPC now more than 20 degrees diameter. Watch
for dust clouds (red filter!). Numerous white patches possible on surface. 

07/30/90 -- Martian Southern Summer Solstice. SPC continues to retreat poleward
Disk diameter 9". 

08/16/90 -- Disk diameter is now 10". Some photography now possible.   Discrete
(white) clouds and white areas should be minimal. SPC small, offset from pole. 

09/01/90 -- SPC retreat slowing--stable polar remnant.  Is Syrtis Major narrow?
Blunted?   Possibility of dust storms again increasing.   Large northern winter 
North Polar Hood (NPH) should be prominent.  Measure latitude of NPH -- does it
retreat or disappear when dust storm present?

09/14/90 -- Disk diameter 12".   Begin high resolution visual observations  and
high quality photography begins.

10/17/90 -- High probability of dust storms.  Disk diameter 15.4". Tilt of Mars
now affording good  view of both polar regions:  large NPH.  Look for tiny  SPC 
remnant near South limb.  SPC offset, so easier to see when CM near 30 degrees.
Is SPC remnant present in mid-summer? 



                    CALENDAR OF EVENTS -- MARS, 1990-91 (con't)

11/09/90 -- Continued alert for dust storms.  SPC  remnant visible?   Antarctic
hazes present?  Is NPH variable, occasionally bright?  (Use a violet filter for 
NPH measurements, observations.)

11/20/90 -- Closest approach (0400 UT) to Earth. Disk diameter 18.1".

11/27/90 -- Opposition (2028 UT). Disk diameter 17.9". Late Southern summer: Is
SPC  remnant still present.  Photographs needed of SPC.  NPH still  observable. 
Watch for signs of NPH thinning. Are South polar hazes present?

12/17/90 -- Disk diameter 16".  NPH should be easily visible if present. Close-
ly monitor hood from now on.  When does it disappear and the NPC appear? Is SPC 
remnant still present?   Any evidence of  SPH?  Watch Syrtis Major for signs of 
expansion to east.

01/05/91 -- Southern hemisphere  autumnal equinox.  Carefully monitor antarctic
region for evidence of SPC remnant and/or hazes.  Will SPH form?  N. hemisphere 
vernal equinox. Monitor arctic closely for date of disappearance of NPH.  Watch 
for possible reformation of polar hood. NPC at maximum extent with edge near 55 
degrees areocentric latitude. Disk diameter 13.2". Begin micrometer/reticle NPC 
measurements, using red/orange filters.

02/01/91 -- Disk diameter 10".  Photography difficult but  visual  observations
and NPC measurements still possible.  Monitor antarctic for SPC remnant, hazes. 
Are Hellas, Argyre brightening?

02/24/91 -- Disk diameter rapidly shrinking--now 8".  Early Northern hemisphere
spring. Continue NPC measurements. Is North Cap fairly static or entering rapid
retreat phase?   South polar regions becoming  difficult to observe.  Any signs 
of SPH?

3/14/91 -- Disk diameter 7".  Limb clouds/hazes should start to increase.  Look
for them in violet light. What is size, shape of Syrtis Major?

04/04/91 -- Disk diameter 6". N. hemisphere mid-spring.  Is NPC beginning rapid
retreat?   Are limb arcs increasing in frequency, intensity.  Use filters! Ant-             
arctic hazes,  hood?  Cloud activity increases.


For complete details for the physical and geocentric positions of Mars send for
the "A.L.P.O. Solar System Ephemeris,"  $6.00 in the U.S,  Canada, and  Mexico;
$8.50 in other countries. Write to: John E. Westfall, A.L.P.O. Director/Editor,
P.O. Box 16131, San Francisco, CA 94116.