Mars Earth/Sun Rise & Set

From: Jan Wee <>
Subject: Mars Earth/Sun Rise & Set
Date: Wed, 09 Jul 1997 09:40:36 -0500

Dear discuss-lfm members,

Thought you would find this info of interest.  It
was shared by PTK Live From Mars host (at JPL)
David Seidel and relates to today's program and
Mars Sol 6!

Pretty interesting comparisons!  Enjoy.

Jan Wee, moderator

Mars Sol 6 / Earth July 9 - 10:

Earth Rise is at 12:47 PM Pacific Daylight Time, July 9

Sun Rise is at 3:57 PM Pacific Daylight Time, July 9

Earth Set is at 2:28 AM PDT, July 10

Sun Set is at 4:59 AM PDT, July 10

Live From Mars (11:00 AM - 1:00 AM PDT, July 9) takes place 
between (approximately) 1 and 3 AM local Sagan Memorial 
Station/Sojourner Truth/Ares Vallis time. In the last 
1/4 hour of LFM, Earth will just be rising as a "morning star" 
at the landing site.

At Earth rise it becomes possible to get a line of sight 
from Pathfinder to Earth.  But no commanding or data downlink 
takes place until Earth gets a bit higher in the sky.  The same 
applies as Earth gets close to the horizon in the Martian afternoon.

When the sun comes up then pictures of the surface can be taken.  
A couple of hours before noon through a couple of hours 
afternoon is when Sojourner is run.

But... the Imager for Mars Pathfinder takes images of 
stars (at night) and Sojourner has batteries that allow it 
to operate at times away from noon (including Alpha Proton 
X-ray Spectrometer measurements which usually take place
at night).

So... from a terrestrial perspective, Earth rise and set 
times are pretty significant.