DIY Equipment test at Comet 123P/West-Hartley

[Astrofriend]

Hi,

I must be stupid man who spend so much time and money on astro equipment when there are no clear sky. But the January 19 there was a clear sky, not perfect but good enoguh to take out the telescope on the balcony. I live close to a city, it's not only the clouds that is the problem, nasty light pollution also. My Telescope is a TS130 APO with a 3" field flattener and the camera is a Canon 6D full frame. Work very good together with very low vignetting and sharp all the way out to the corners. Control it from an astroserver that is built around a mini PC. Nowadays I can have it setup in just one hour. I have the mount stationary on the balcony at the winter and normally there is no need to polar aligne it. From that I mount the telescope on the mount and until it had cold down I have everything started up, focused, pointing correct and tracking with auto guidning. Not bad, earlier it could take three hours until I could start taking photos.

 

But the comet, did I get anything? The comet 123P/West-Hartley was at this time weak with a magnitude at 12.9. I was not sure if it was possiblie to get anything. But after I had staked my 40 x 30 seconds images I could clearly see the comet.

I have it here at my homepage with some more information:

http://www.astrofriend.eu/astronomy/my-astronomy-photo/comets/123p-west-hartley.html

I also tried to make a time lapse movie of it, but the move of the comet was too small to see anything. But first I had to make a monochrome images of the RGB imges to get the noise down, with out that it wasn't possiblie to align the comet.

 

The process goes like these:

Dithering taken images

Subtract constant

Demosaic (no interpolation debayering)

Flat calibration

Aligne at one point at a star close to the comet

Recombine RGB images to mono (second time I keept the RGB version)

Aligne at comet (second try I skiped this)

Stack

Adjust color gains

crop out borders

Subtract backgrund

 

To do the RGB to Mono combine I had to make a new macro for the AstroImageJ software I use.

 

It just took me 12 hours to have a noisy comet image and I'm happy with that ?

 

/Lars

[happy-kat]

That does look a faint comet, but you captured a record of it, that's great.

[Astrofriend]

Yes, when living close to a city you can't have to big expectatoins. But this was fun. Objects along the eclipta I just have two capture between they leave the horizon and get hide behind the building in front of our balcony.

 

Lars