Starlink 2-BD - 2020-001-BD - 44965 - MY FIRST IOD Observation - Not very precise, but I hope it helps

From: Gonzalo Blasco via Seesat-l <seesat-l_at_satobs.org>
Date: Mon, 11 May 2020 17:54:15 -0500
Hello all,

TAKE CARE THEY ARE MY FIRST IOD REPORT EVER!!!
Any comments will be appreciated...

Last afternoon I checked in Heavens Above that i will have a very near pass
of a (decaying) Starlink satellite 1086 - Starlink 2-BD - 2020-001-BD -
44965.

MY OBSERVATIONS:

44965 20 001BD  9999 P 20200511015129800 57 75 1026017+217830 85
44965 20 001BD  9999 P 20200511015127600 57 75 1018442+195860 85

OBSERVATORY DATA:

NAME: ZAPOPAN TINACO
20.75439N -103.37516W alt 1570meters

(I have more photos in the same pass, but I want to check before if they
are useful to send them because if I take more time they will be probably
outdated... if they are not already ) :-(

====================================
A LITTLE ABOUT THE EXPERIENCE
====================================

As I told, I checked in heavens above and It would have a MAX height of
84degrees and a distance of 286km (I think this is quite near)

https://photos.app.goo.gl/zSGgZR1o8FyjZCWF9

Then I checked in CALSKY and it seems a decaying satellite, so I found the
orbit observation COULD be interesting.... Probably if i made the
calculations before :-( . Im too slow processing the data yet.

====================================
ABOUT THE SAT
====================================
Name:          Starlink 2-BD
Also named:    Starlink 1087
*Decays:        12 May 2020 22:23 UTC (predicted)*
Brightness:     6.5 mag (at 1000 km, 50% illuminated)
                3.1 mag (at perigee, full illumination)
USSPACECOM Nr: 44965  Internat. Designator: 2020-001BD
====================================

I had clouds.... so it was quite difficult to see anything, and my sky was
still blue (the sun was at -7degrees) so I setup the camera and make a
series of 2 second photos and wait what happen.

At naked eye I didn't see anything, but after downloading the photos, I
watched the trails in about 6 photos, and about 1 minute after the
predicted time of heavens-above....(quite long difference)

I checked that the CALSKY calculations was based in *very** recent TLE of
SATEVO, *so I checked them, and They were more accurate with my
observation.... and the difference was about one or two second....

The good luck of my photo is that the sat was passing at 1 degree left of
ALGIEBA (41 LEO), but passed clearly at the right. It was a clear
difference!!

====================================
ABOUT THE TIME UNCERTAINTY
====================================

I did some experiments in recent days, and I was quite to know at least to
see if the capture was made in the early part of the second or in the last
part... so it was better than a +-1sec uncertainty . I am about +-0.5sec
uncertainty. Also i made some experiments about the sync of the camera, and
was quite good with less than 0.2secs I think... so I guess that +/- 0.6
secs is a nice guess for this one.

END (EXIF)
2020 05 11 - 01:51:30.2 UTC -0.43OFFSET
EXPOSURE: 2.19sec


START: 01:51:27.6
END: 01:51:29.8

Uncertainty +-0.5

  ====================================
ABOUT THE POSITION UNCERTAINTY
====================================
I used ASTROREC following the Marco Langroek PDF written 22 May 2016

Of, I had VERY few stars (about 8) , but I had made previous experiments
with another well predicted satellites, and the uncertainty of the
medition could be with a std deviation of about 40-50 arcsecs in this case,
and about 20-40 with more reference stars.....

Then I plot the points of the medition / measurement in Aladin over a DSS
photo and I measured if the trail was in the correct position like in the
photo. And all seem fine!!!

I have not the right tools, so its a bit difficult, and was poor
observations, but I think I could be doing better next time....

After watching the results against a chart of CALSKY, the time difference
was below 1sec, and the satellite passed about 50minutes at the predicted
position.

The total trail during the 2.19sec exposure was of 2.75degrees

====================================
THE LAST ONE OR TWO ARE MY BEST MEASURMENTS WITH ASTROREC
====================================
"44965   " 2020 05 11 01 51 30   0.0 27.83 0.03 154.684  19.586 156.503
 21.788 0.019   0 "IMG_8905" "ZAP BOSQ TINACO   "
"44965   " 2020 05 11 01 51 30   0.0 27.83 0.03 154.684  19.586 156.503
 21.788 0.019   0 "IMG_8905" "ZAP BOSQ TINACO   "
"44965   " 2020 05 11  1 51 30   0.0 27.83 0.02 154.682  19.591 156.509
 21.787 0.012 100 "IMG_8905" "ZAP BOSQ TINACO   "
"44965   " 2020 05 11  1 51 30   0.0 27.81 0.02 154.684  19.586 156.507
 21.783 0.012 100 "IMG_8905" "ZAP BOSQ TINACO   "

====================================
ABOUT ALL THE PROCESS
====================================

I made screen captures of all the process, so if you want to check all the
measures over and the photos... you can access my captures here:

https://photos.app.goo.gl/GWkZf56uZgaUwfoq7

I want to thank Marco Lanbroek and Jonathan McDowell for all the inspiration

and specially for all you guys who have helped me with my questions: Leo
Barhorst, Charles Phillips and  Brad Young

Thank you,

--
Gonzalo Blasco Gil
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Received on Mon May 11 2020 - 17:56:05 UTC

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