Mir Marathon

Dave Mullenix (djmullen@facstaff.wisc.edu)
Sat, 08 Jun 1996 03:04:20 -0500

colston@viagrafix.com (Lloyd Colston) relayed a message written
by Dale Ireland to the amsat-bb mailing list:

>      Date:  Wed, 05 Jun 1996 07:47:39 -0700
>Newsgroups:  sci.astro   
>      From:  Dale Ireland <direland@olympic.net>
>Once a year the orbit of the space station MIR and the Earth's
>inclination combine to produce a situation such that MIR nearly
>follows the day-night terminator throughout it's orbit and so
>is visible all night on every pass. It may be possible to see
>as many as 4 consecutive passes theoretically 5.

Not just theoretically, it has been done.  I saw Mir on five
consecutive passes on the night of June 27-28, 1992.  The passes
were at 21:52, 23:27, 01:05, 02:42 and 0418 CDT (UT -5 hours)
from Madison, Wisconsin, (-89.3819,43.0730).  

The first and last passes were in very bright twilight and
required 7x50 binoculars to see Mir against the blue sky.  The
sun was barely below the horizon and there was enough light to
easily read a newspaper and for full color vision.  Mir was
completely invisible to the naked eye on both the first and last

On the fifth pass, I only found Mir because I had a printed
chart showing Mir's path against the stars and planets.  I was
able to find stars and planets it would pass while it was still
dark and establish various landmarks such as trees and chimneys
to sight over.

It helped that Mir's path took it past Jupiter, which remained
visible in binoculars until Mir came by.  Jupiter will be in the
morning sky again this year.

>This is the week! For the next few nights centered around June 8 MIR 
>can be seen on nearly every pass. 

I'll be out tonight, June 8/9, trying for a second Marathon,
weather permitting.  This year we'll also have some Mir debris
to look for.  There have been reports of three to nine objects
preceeding Mir.  They are reported to be easily visible in 7x50

Hams and radio buffs should also monitor 145.55 MHz and the new
UHF frequencies which MAY be active or in test mode by now.

                  Downlink   Uplink
MODE 1 REPEATER   437.950    435.750   PL Required
MODE 2 PACKET     437.975    435.775   NO PL
MODE 3 QSO        437.925    435.725   PL Required

Shannon Lucid, the American astronaut on board Mir, is most
likely to be heard on 145.55 during the early morning passes,
which occur between morning wakeup and the start of daily duties
on board Mir.

>A visibility list by city may be found at the SKY and Telescope
>web site www.skypub.com.

I also highly recommend using a program that plots Mir's path
across the stars and planets to help bag the morning twilight passes.

I call seeing Mir five or more times in one 24 hour period a Mir 
Marathon and cordially invite all interested to try one.  

Dave Mullenix, N9LTD