Video: Pro & Con

R.B. Minton (
Tue, 25 Jun 1996 12:14:58 -0600

Hello Bart and others who may be interested in video observations:

I've been told that our server is acting-up and since its been over 24 hours
since I posted my last message (with no response); I'll do it again but with
a slant on group participation - and addressed to Seesat-l.

I'm an active video observer of satellites, but there is apparently a problem
on reducing these observations to provide meaningfull DRA data.  Observing only
3 satellites I have found that the maxima and minima are so gradual (flat or
shallow) that the measures of the times of maxima and minima are only good to
1 to 5 seconds.  Bart says that 0.5 sec. accuracy is required, so we are now
thinking of ways to reduce video observations into precise times of maxima.
Suitable methods must not require too much time or effort since there are a lot
of satellites and even more potential observations.
Three ideas come to my mind, but I invite all Seesat-l members to brainstorm
along with us for a good solution.  My 3 ideas (as of now) are:
1.  Build a 2-channel photometer to slide-around on the face of a TV screen so
that the satellite is under 1 and the sky is under the other.  The satellite
signal would be A-B.  The output would go to a chart recorder and times of 
maxima/minima noted.  The method would be fairly fast, but dependent on good 
initial tracking and good subsequent centering of the photometer.  I have used
a 1-channel device before with some success.
2.  Digitize the TV images and do a bona-fide photometric reduction.  I have a
CCD and reduction software (MIPS) suitable for this; but I believe this is too
time-consuming and labor-intensive for routine contributions.  Does anyone else
have another slant on digitizing, but with faster reductions?
3.  View the TV with a stopwatch and record the times just like most other 
Seesat-l members.

Does anyone out there have experience with frame-grabbers and some sort of PC
image reduction (of stellar looking images)?

I invite discussion on this topic, especially since video recording is mentioned
in the announcements of topics for Eurosom 2; and the general trend is towards
electronic imaging - although I strongly doubt it will ever replace visual data.

P.S.  Although I have been a member of Seesat-l for months, I never posted my
introduction - so here it is....  I've been an amateur astronomer since I was
13 (now 56), got paid for doing astronomy for 12 years, playing with computers
since 1969, and have got paid for playing with computers pretty much since then.
I had the pleasure of working for Martin Marietta Aerospace for 10 years as
a software engineer and a threat analyst for their National Test Bed (star wars)
program.  I was fortunate to spend 3 nights atop Mt. Haleakala observing how 
the Air Force studies satellites.  (Yes Mr. John Pike - this is why I am so
familiar with AMOS - the Air Force Maui Optical Tracking Station).

R. B. Minton