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

From: Leo Barhorst via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 12 May 2020 07:01:33 +0200
Hello Gonzalo,

Congrats with your 1st IOD observation.
A nice result.

Greetings
Leo

Op di 12 mei 2020 om 00:54 schreef Gonzalo Blasco <gblasco_at_gmail.com>:

> 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 outdated...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 Tue May 12 2020 - 00:02:52 UTC

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