Sky and Telescope - January 2016 - 53

Klaus Brasch got interested in astronomy as a teenager around the time
of Sputnik 1 and has been a keen lunar and planetary observer ever since.

Klaus Brasch

The global IPPP network routinely recorded the planets on a nearly hourly cadence. This sequence shows Mars on May 27-28, 1969.

Solar System Sentinels
William A. Baum (1924-2012), a remarkably versatile
investigator and pioneer in many areas of astronomy,
led the IPPP team. Other key contributors included
cartographers Leonard J. Martin (1930-97) and Jay L.
Inge (1943-2014). Probably best known to seasoned Mars
observers and to Sky & Telescope readers was astronomer
Charles "Chick" Capen (1926-86).
The IPPP had a very speciﬁc goal: to secure and
archive uninterrupted planetary observations in support of the soon-to-follow NASA planetary space missions. The global network consisted of six and later eight
observatories equipped with telescopes having 24- to
26½-inch apertures, including classical refractors like
Lowell's 24-inch Clark and four specially built 24-inch
f/75 Cassegrain reﬂectors.
Baum's team also designed advanced 35-mm ﬁ lm
cameras that incorporated innovative focusing, guiding,
color-ﬁlter selection, and calibration. Whenever possible,
observers recorded the planets hourly at each station
on Kodak 2498 RAR ﬁ lm, in 14-exposure sequences
through red, green, blue, and ultraviolet ﬁlters, along
with the date, time, observer, location, and color on each
frame. Later, technicians in Flagstaﬀ developed all the
ﬁlm under tightly controlled conditions. By the time the
IPPP ended in the late 1970s, its observers had obtained
some 1.2 million individual planetary images.
While IPPP participants monitored all major planets,
their most productive results involved Mars. A half century of prior visual and photographic work had documented numerous atmospheric phenomena, including
yellow, white, and blue clouds; dust storms; polar hazes;
and a recurring W-shaped cloud over the Tharsis region.
Since analysts were unsure about the exact nature of
most Martian atmospheric features at the time, they
classiﬁed them on the basis of the color or wavelength at
which they appeared most prominent.

To learn more about the project's key players,
visit http://is.gd/IPPP_extras.

The IPPP's observers documented major dust storms
in 1971 and 1973 and continued to scrutinize the Red
Planet up to the Vikings' 1976 arrivals. The earlier storm
coincided with the arrival of Mariner 9 and blanketed
the orbiter's view of the Martian surface for several
weeks. IPPP imagery helped establish not only the
dynamics and speed of the storm's development but
also enabled understanding of climatic changes on the
planet, including cloud formation and seasonal variations in the polar caps.
We learned to distinguish between polar ice and the
often more extensive polar "hood" of clouds that extended
Left: Observers used
this custom-designed,
semi-automated,
35-mm ﬁlm camera
for all IPPP planetary
photography.
Below: The Solis
Lacus region on Mars
erupts with a major
dust storm in this
month-long sequence
of IPPP tri-color composite images. Day 1
is October 13, 1973.

LOWELL OBSERVATORY (3)

race and the promise of human exploration to the Moon
and later Mars, left a glimmer of hope that the Martian
environment might be relatively benign. Hence, as late
as 1965, the idea persisted that the color and apparent
seasonal darkening of some Martian features might be
due to lichen or similar vegetation.

Sk yandTelescope.com Januar y 2016

http://www.is.gd/IPPP_extras http://www.SkyandTelescope.com

Sky and Telescope - January 2016

Table of Contents for the Digital Edition of Sky and Telescope - January 2016