Hello David
I did not give my coordinates at SeeSat since
I am a regular
video observer there and well known to those that
normally
do orbital analysis of observations so I guess you are not
a
regular user :-))
Incidentally we have communicated in the past - quite a
few
years back. Ive forgotten the exact details now as I guess
Im
beginning to get a bit absent minded :-)). I am a retired
professional
astronomer and used to work at the South African
Astronomical Observatory
until I retired in October 1999.
Okay my site details are:
Cospar
0433
Longitude 18.512944 E, latitude 33.940583 S, alt 15 metres
(GPS
derived)
Location Pinelands which is a suburb of Cape Town.
I have
been in contact with George Lewis at JPL for many
years and have forwarded
positional information on such
events as the Messenger and Rosetta flybys of
earth to him
and he approached me about a month ago to do what I could
for
the STEREO mission-hence my observing it.
In the light of your interest
in these observations I guess
you would like more. I originally did not plan
to make any
more measurements from the DVD or hard drive recordings
as I
did not think they were of that much interest but if you
wish I can make more
as I observed the object out to about
11000 kilometres range.
In view
of the particular lens/ccd combination I was using
at the time I am pretty
sure that the STEREO craft would
not have been resolved as two individual
satellites as the
field of view was approximately 4.43 x 3.55 degrees.
I
will attach two frames extracted from the video to give
you an idea of
the quality etc. The time of the frame is given
in UT in left bottom corner -
eg 01h22m and seconds.seconds.
(a bit blurred in the seconds as several video
frames are
superimposed to reduce the noise a little but no problem
to
extract all the individual frames. I used a MINTRON low
noise level
surveillance camera and the camera tracked on the
object so object will
appear stellar and stars will trail- all
under computer control - the
so-called CoSaTrak system.
If I can help in any further way I will be
only too pleased
to do what I can
Best wishes
Greg
Roberts
----- Original Message ----- From: "David Dunham"
<dunham@starpower.net>
To: <grr@telkomsa.net>
Cc:
<joan.dunham@ai-solutions.com>;
<david.dunham@jhuapl.edu>;
<jose.guzman@jhuapl.edu>;
<peter.sharer@jhuapl.edu>;
<jdg@tycho.jpl.nasa.gov>;
<bdickson@telkomsa.net>;
<mir16609@verizon.net>;
<bill@iway.na>
Sent: Thursday, October
26, 2006 6:13 PM
Subject: Re:
STEREO
>Greg,
>
> Many
thanks for your observations and interesting
>report at
>http://www.satobs.org/seesat/Oct-2006/0182.html
.
>
>If you're right and you observed the 3rd stage booster, then
they are probably
>the only observations that we'll get of it after the
injection, and valuable
>for determining the injection error, as well as
the 3rd stage impact on or
>about Nov. 6. But I suspect that the
spacecraft might not have separated
>enough to have been resolved by then,
and you were just seeing them; we should
>be able to determine that by
comparison with FDF's trajectory that's been
>determined from the DSN
tracking. But first we need to know your location;
>please send
that. So far, I know of no other optical observations,
other
>observers reporting clouds too thick to get
any.
>
>David Dunham,
>STEREO Mission Design
Team
______________________________________________________________
Hi David
After having done some measurements along the
track I
observed I personally am now convinced that what I saw
was the
actual spacecraft. The agreement of prediction
vs observation, at least
as far out as a range of 11000 kms
was just too good to have been anything
else, so unless Im
convinced otherwise I think I can claim to having seen
the
STEREO satellites ( unresolved)
:-)).
Cheers
Greg
Observations 26 Oct
2006:
-------------------------------
Cosatrak 1 (Computerised
satellite Tracking System).
MINTRON low light level CCD surveillance camera
(0.005 lux typical
in non integration mode) and 0.00005 lux in STARLIGHT mode
with 128
frame integration.
Used with 75mm focal length f/2.5
lens,integrating for 96 frames
which is equivalent to an exposure of 1.92
seconds per image.
Approximate field of view 4.43 x 3.55 degrees.
For
the last measurement the focal length was changed to 150mm
giving an
approximate field of view of 2.40 x 1.89 degrees but
deeper magnitude
penetration. Pity the clouds then came in force :-((
Site 0433 : Longitude 18.51294 deg East, Latitude
33.94058 deg S,
Elevation 10 metres - situated in Pinelands (Cape Town),
South Africa
29510 06 047A 0433 F 20061026012139300 56 15
0546598+300507 39 +085 05
29510 06 047A 0433 F
20061026012142400 56 15 0548450+294415 39 +083 05
29510 06
047A 0433 F 20061026012159200 56 15 0558218+274958 39 +075
05
29510 06 047A 0433 F 20061026012232800 56 15 0615513+240525
39 +080 05
29510 06 047A 0433 F 20061026012333000 56 15
0642574+175058 39 +080 05
29510 06 047A 0433 F
20061026012542700 56 15 0727189+065440 39 +080 05
29510 06
047A 0433 F 20061026012642800 56 15 0743094+030225 39 +081
05
29510 06 047A 0433 F 20061026012813200 56 15 0803090-013909
39 +083 05
29510 06 047A 0433 F 20061026012911500 56 15
0814005-040533 39 +087 05
29510 06 047A 0433 F
20061026013041800 56 15 0828441-070804 39 +085 05
29510 06
047A 0433 F 20061026013143800 56 15 0837377-085550 39 +088
05
29510 06 047A 0433 F 20061026013244100 56 15 0845114-101553
39 +089 05
29510 06 047A 0433 F 20061026013412000 56 15
0855220-120308 39 +090 05
29510 06 047A 0433 F
20061026013512200 56 15 0901409-130404 39 +088 05
29510 06
047A 0433 F 20061026013720000 56 15 0913229-145000 39 +087
05
29510 06 047A 0433 F 20061026014012800 56 15 0926520-163559
39 +089 05
29510 06 047A 0433 F 20061026014419800 56 15
0942304-182304 39 +081 05
Notes:
--------
(1)
After having done the above measurements and seeing the
excellant
agreement with the predictions supplied by
HORIZON I am convinced
that what I saw was the actual
STEREO spacecraft, but unresolved
as a result of the small
image scale. The first measurement was
done at a range of
about 3100 kilometres and the last at about
11070
kilometres. The object/s was slowly varying in brightness
and I suspect this was due to the slow spin of the
satellites.
Towards the end I could only see the brighter
magnitudes.
Unfortunately cloud packed in solid after I
had changed the
telephoto lens focal length but I did
continue tracking until
a range of about 22000 kms or so -
I have still to examine the
DVD recording during this
period so may have yet another observation
but I doubt it.
One of the brighter spells of the satellite
may have got
as bright as magnitude +6.5 or so.
(2) The observations above are, as I
always do, reported in IOD format.
The format is
described at
http://www.satobs.org/position/IODformat.html
Cheers
Greg