M3 with digital SLR

[johnturley]

My first attempt at the above through my f5 14in Newtonian, just a 30sec exposure with my Canon 6D at ISO 1600, and just a few minutes processing in Adobe Lightroom.

Fairly basic, but did not involve multiple imaging, stacking, and hours of processing.

In addition (although I do have one), I did not use a coma corrector, and the stars at the edge of the field do not appear to show a massive amount of coma.

John 

Edited April 25, 2020 by johnturley

[johnturley]

Thanks for all the likes regarding the above.

I have also attached a shot of M51, which I took with the same settings.

I know that it does not compare with most of the images of this that have been posted on SGL, but as I stated before it was not taken with a specialised astrophotography camera, and did not involve multiple imaging, stacking, and hours of processing, just a few minutes enhancing the image and darkening the background in Adobe Lightroom. Don't know whether I would to better with more specialised astrophotography software such as Pixinsight, in addition I have taken images in both JPEG and RAW format, but the latter did not appear to offer any particular advantage, and took up a lot more megabytes on the SD card and computer hard drive. 

Interestingly I got out an old astrophotography book from the 1980's, the Cambridge Deep-Sky Album by Jack Newton and Philip Teece, and my images do appear better than what could be achieved at the time using cooled emulsion film cameras, and amateur telescopes. 

John 

Edited April 26, 2020 by johnturley

[x6gas]

For single shot images and only 30s exposures these are incredible!  Just shows what a light bucket you have on your hands!  I'd really encourage you to take multiple exposures and start stacking.  Deep Sky Stacker is all you need to get you started and it's free.  PixInsight is excellent and very capable but with capability comes complexity and the greatest bump you'll get right now is taking multiple images and stacking them.

By the way, it's definitely worth capturing your frames as RAW files - it will allow you to get the absolute most out of your data as you progress.  JPEG uses compression and you lose hard won information so best avoided for processing.

Excellent stuff, though.  Well done.

[johnturley]

18 hours ago, x6gas said:

For single shot images and only 30s exposures these are incredible!  Just shows what a light bucket you have on your hands!  I'd really encourage you to take multiple exposures and start stacking.  Deep Sky Stacker is all you need to get you started and it's free.  PixInsight is excellent and very capable but with capability comes complexity and the greatest bump you'll get right now is taking multiple images and stacking them.

By the way, it's definitely worth capturing your frames as RAW files - it will allow you to get the absolute most out of your data as you progress.  JPEG uses compression and you lose hard won information so best avoided for processing.

Excellent stuff, though.  Well done.

Hi x6gas

Thanks for your comments

I've tried longer exposures (1-2 minutes), but found a big increase in background brightness (probably due to light pollution), and also showed imperfections in the tracking. So I think that 30 seconds (which is incidentally the longest manual exposure setting with my Canon 6D) is just about on limit for an unguided shot with my current set up. The mount is a massage fork equatorial, in appearance not totally dissimilar to the Paramount Taurus (which sells for £25,000 +, and I paid just under£3,000 for the whole set up in 1984), but the drive system is very much based on 1980's technology being a 1/2 rev per minute mains synchronous motor via a 12in diameter 720 brass (not aluminium as on the Taurus) worm wheel. This requires a variable frequency oscillator to change the mains frequency from 50 to 50.14 hz, and the mains frequency varies slightly. I used to have a frequency meter so I could adjust the frequency to exactly 50.14 hz , but this no longer works (I keep meaning to try to get it repaired). In addition I moved the observatory shed and telescope 2 years and may not have realigned the mount exactly since then, and the only way of checking this is manually by trial and error based on drifting of star images (no polar scope or PEC available). I may also have loaded it a quite heavily mounting the Esprit 150 piggyback and with 15kg of counterweights, but its fine for visual (a planet at 200x will stay in the field of view for over an hour). Visual observation of the moon and planets is my main interest, and I only occasionally delve into deep sky imaging.

I will however have a look at Deep Sky Stacker, maybe it will also help with planetary imaging, although to be honest I'm never likely to be into spending hours stacking and processing images. My Canon 6D also has RAW + JPEG modes so that I can check the images and delete poor ones, rather than waste time loading them into Adobe Lightroom before I can view them (I cannot view the unprocessed CR2 files with my PC). 

John