A mysterious visitor

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hhzhang
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Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

A mysterious visitor

Post by hhzhang »

When taking the M11 and starfield last night (see my other post), I noticed a trail in a frame, it moved in the next frame, and so on. My measurement indicates the trialing speed is about 15arcsec/sec. Wow, is it a geostationary satellite?

In the next two minutes I stopped the original sequence and the tracker, therefore captured the position of the object while the celestial objects were trialing in the image. Its image was still a point in every one of my 15s or 30s exposures. It was almost confirmed a geostationary satellite.

But wait! The point seemed to be moving laterally (DEC) across the exposures. Here goes the animation.

Image

It moves at a speed of 30arcsec roughly every 2 minutes. This is trivial compared to its 15arcsec/sec speed around RA axis.

LIkely it was at an altitude similar to geostationary satellites, or 36000km. Given its brightness at such a distance, the size must be considerable.

Just, what could it be? Could it even be a near earth asteriod?

If it is an asteroid, its orbital inclination is nearly perfectly aligned with the earth's equator, not the ecliptic. This is somewhat unlikely.
Last edited by hhzhang on Wed Aug 19, 2020 12:04 pm, edited 1 time in total.

hhzhang
Posts: 94
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: A mysterious visitor

Post by hhzhang »

Finally I figured out it must be nothing but a geosynchronous satellite.

https://en.wikipedia.org/wiki/Geosynchronous_orbit

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Airconvent
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Re: A mysterious visitor

Post by Airconvent »

Yes...too many of these now. It used to be you are very excited to see them. But these days, astrophotographers and even serious astronomers hate it.
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hhzhang
Posts: 94
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: A mysterious visitor

Post by hhzhang »

Airconvent wrote:
Sun Sep 13, 2020 6:34 pm
Yes...too many of these now. It used to be you are very excited to see them. But these days, astrophotographers and even serious astronomers hate it.
Geosynchronous artificial satellites are still far less common than low orbit ones. I have encountered the latter in many of my subs but this is the only one doing geosync motion.

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