Astronomie en Visuel Assisté / Electronically-Assisted Astronomy

I captured Comet Borisov on my second outing. It isn't a pretty object, but it was an interesting challenge.

The skies were average. This means, that the stars were dancing at the low altitude of the comet. I was also shooting over the top of a large building that has floodlights. And I was shooting over the top of a light dome. This was least desirable of all possible positions for my location (of course).

The comet was mag 16.3 at the time.

The comet appears to be elongated in the integrations, due to it's movement. The comet appeared more star like in single exposures. I was trying to lock on to, and therefore freeze, the comet with the autoguider when I ran out of time and the sun came up.

Tips:
If you try to capture this comet in Sharpcap, be sure to turn off Sigma Clipping or it will eat some of the comet tail.

I used this online calculator to convert the comet's J2000 coordinates that are reported online, to JNOW coordinates that I could use with CdC. The conversion worked like a charm and the comet was near the center of the field on the first try.

I tried various exposure lengths. There wasn't much difference. 30 second exposures had a slight advantage.

ASI183MM Pro, 4x4 bin (1.1 asec/px), gain 130, cooler -30F. SkyWatcher 16" 1800mm f4.4 Newt on GEM, autoguided. Cartes du Ciel, Sharpcap, PHD2.

9x30 sec, saved as viewed, cropped 243x5sec This image shows how far the comet moves in 20 minutes

I like that. Maybe one day, I would do the same thing....

Woaw, very nice challenge and for a comet with this magnitude you have a beautifull result

Could you tell us the field size of you fisrt crop ?

Edit: ok found it

Ubuntu a écrit : ↑

08 déc. 2019, 09:46

<font style="vertical-align: inherit;"><font style="vertical-align: inherit;">Wow, very nice challenge and for a comet with this magnitude you-have a beautifull result: D </font></font>

<font style="vertical-align: inherit;"><font style="vertical-align: inherit;">Could you tell us the size of you fisrt field crop? </font></font>

<font style="vertical-align: inherit;"><font style="vertical-align: inherit;">Edit: ok found it: D </font></font>
<font style="vertical-align: inherit;"><font style="vertical-align: inherit;"> capture.jpg [/ attachment]</font></font>

Thank you Ubuntu, Here is the full image. I had cropped it for CN to meet their image size limits. I forgot that we don't have those limits here.

I should note that if you try to find the comet, it wont be where I found it. It is moving lower in the sky each night. Here is a web page that provides the current location. https://theskylive.com/c2019q4-info

Be aware that the coordinates on that web page are in J2000. You may need to convert them to JNOW. Here is a web page that has a conversion calculator. http://www.robertmartinayers.org/tools/coordinates.html

Thanks you @Rickster for this very interresting shot!