[amsat-bb] ARISSat in sunlight

[John Heath]

Interesting thread regarding  MET and ARISSat-1 switch on.
 
Someone made the very good point that the transition in or out of sunlight 
(eclipse) is not an on/off event. I remember many MIR visuals, and as she 
passed 
from sunlight in the west to darkness in the east there was a significant time, 
perhaps a minute or more when she changed colour from bright and silver white 
to 
orange then disappeared into blackness. I always interpreted that as passing 
through the penumbra, or semi shadow area.
 
ARRISat-1 is at at around 370km, does anyone know how to find the width of the 
penumbra  at that altitude?
Working out the transit time through that region might be informative.
 
 
73 John G7HIA
___
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

[amsat-bb] ARISSat in sunlight

[Simon Pack]

Using Orbitron 3.71 software, I can tell that the penumbral duration today 
was 9 seconds. However, this will vary in the future as the angle of the 
orbit to the sun changes. However, the first sunlight the satellite will get 
will be very red (due to the blue light scatter caused by the atmosphere). I 
have observed that ARISSat-1 doesn't start transmitting for a further 14 
minutes.


To be more precise, I am seeing the Mission Elapsed Time (MET) counter start 
counting from zero about 40 seconds after coming out of eclipse, and the 
first BPSK telemetry frame has a MET=808. The first KURSK experiment data 
isn't transmitted until MET=945. However, since 12th September the KURSK 
experiment appears to have failed and is only sending null data.


73s, Simon G7WIQ 


___
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb