Observation 14895793: ISS (25544) TLEs off?

Regarding Observation 14895793

Thanks to ChatGPT looks like some of my ISS observations had a doppler shift. I was figuring some old TLEs were being used with the 1.28 update.

1 Like

Indeed there wasn’t any TLE update on 28th of August for ISS, so in combination with the boost you linked it resulted to this doppler shift. Nice catch!

1 Like

Element-side confirmation of exactly that: the epochs I hold for 25544 jump from 08-27 12:44 UTC straight to 08-28 21:15 UTC — nothing in between, so observations on the 28th flew on a pre-boost element set. The current set (epoch 08-29 06:32 UTC) is post-boost.

The previous sets I hold are epoch 08-28 21:15 and 08-27 12:44.
So if your observation was scheduled against an element set from the 27th, that’s nearly two days of ISS drift, and a reboost in that window would move AOS by tens of seconds.

Worth re-checking against the 06:32 epoch.

1 Like