Re: USA 276 approaching ISS again

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Thu, 13 Jul 2017 15:33:04 +0200
Op 13-7-2017 om 14:34 schreef Alberto Rango:
> Hi Marco,
> 
> this morning,  two  o' clock zulu I was there,  at  my site 4542,
> waiting for ISS  and  USA 276


Hi Roberto, others,

It is important that we keep following this satellite as frequently as possible.
I hope to get some insight into whether things happen just before during and
after such close approaches, in terms of orbit adjustments.

Close approaches will repeat in semi-monthly intervals.

The updated orbit below is based on observations by Alberto Rango, Leo Barhorst
and Andriy Makeyev:

USA 276                                                  387 x 407 km
1 42689U 17022A   17194.07884632 0.00004840  00000-0  66047-4 0    07
2 42689  50.0114 265.6967 0014941 288.7489  71.1858 15.56648112    07

rms 0.017                          from 6 obs Jul 9.04 - Jul 13.09 UT


I get these close approach times and distances from these:

7/13/2017	00:35:43	474.4
7/13/2017	01:23:57	460.6
7/13/2017	02:08:19	402.9
7/13/2017	02:56:14	389.7
7/13/2017	03:40:55	331.4
7/13/2017	04:28:31	318.7
7/13/2017	05:13:31	259.8
7/13/2017	06:00:48	247.7
7/13/2017	06:46:07	188.3
7/13/2017	07:33:06	176.9
7/13/2017	08:18:42	116.8
7/13/2017	09:05:25	106.3
7/13/2017	09:51:18	 45.3
7/13/2017	10:37:43	 37.9
7/13/2017	11:23:54	 26.5 *
7/13/2017	12:10:02	 41.3
7/13/2017	12:56:30	 98.0
7/13/2017	13:42:22	110.0
7/13/2017	14:29:06	169.6
7/13/2017	15:14:41	180.6
7/13/2017	16:01:42	241.1
7/13/2017	16:47:01	251.6
7/13/2017	17:34:18	312.7
7/13/2017	18:19:18	322.7
7/13/2017	19:06:54	384.3
7/13/2017	19:51:42	393.8
7/13/2017	20:39:29	455.9
7/13/2017	21:24:03	464.9

Approach distances have some uncertainty, perhaps up to a factor 2.

A few more nights of data on USA 276 might help with a better orbital resolution.

I myself was clouded out here, after the earlier part of the night was clear.

- Marco


-----
Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.
e-mail: sattrackcam_at_langbroek.org

Cospar 4353 (Leiden):     52.15412 N, 4.49081 E (WGS84), +0 m ASL
Cospar 4355 (Cronesteyn): 52.13878 N, 4.49937 E (WGS84), -2 m ASL
Station (b)log: http://sattrackcam.blogspot.com
Twitter: _at_Marco_Langbroek
-----
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Received on Thu Jul 13 2017 - 08:33:38 UTC

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