[ap-ug] Challenge object: Tiny faint galaxy grouping in Ursa Major

Roland Christen

How far off the zenith was the line of sight for the images?
This object was near the zenith at the time I took this image.


-----Original Message-----
From: Jay Freeman via groups.io <Jay_Reynolds_Freeman@...>
To: main@ap-ug.groups.io
Cc: main@ap-gto.groups.io
Sent: Thu, Apr 28, 2022 12:01 am
Subject: Re: [ap-ug] Challenge object: Tiny faint galaxy grouping in Ursa Major

If you zoom the posted image, there are two "spiral" trails, one much fainter than the other, side by side. The faint trail extends farther toward the bottom of the frame than the bright one -- in fact, off the frame -- which I suspect makes it unlikely that one trail is an optical or processing artifact of the other. 

If the object(s) is(are) actually "spiraling", the rate of rotation is awfully fast -- remember, the lateral motion is at orbital speed, likely at an angular rate on the order of a degree per second as seen from the ground. Might alternatively be something rapidly flashing, reflecting off something ring-shaped.

How far off the zenith was the line of sight for the images? Knowing that, and remembering that an arc second is about one meter at 200 Km, and assuming that it is high enough to be in orbit, would give a lower bound on the size of the thing.

Could it be closer than in orbit?

I think the big mystery is, that there appear to be two of them..

-- Jay Reynolds Freeman
(personal web site)

On Apr 27, 2022, at 6:54 PM, Roland Christen via groups.io <chris1011@...> wrote:

Wanted to see how faint I could go here at my light polluted industrial park. Local amateurs pointed out a tiny grouping of faint galaxies that they haven't been able to get much info on them or any detailed images. I tried with my 130EDF, 10" F8 Mak-Cass and finally with my 17" F8 Astrograph. Main limitation is the amount of background sky brightness here due to severe light pollution, but I'm always up to a challenge. The galaxies showed up in a wide field image in my 130GTX as a tiny little group, showed some small amount of detail in the 10", but it took the 17" to finally reveal some better detail. 
Star resolution last night was 1.5 arc sec FWHM and guiding was under 0.2 arc sec FWHM for the 20 minute exposures. Had some horrific satellite trails that had to be removed, otherwise everything went fairly smoothly.


I had one satellite trail that resembled a corkscrew, never have I seen anything like that. See below.


Roland Christen