I have always been interested in imaging, ever since I owned a very good CCD camera, the MX5 in the middle half of the 1990's.
In 2006 I bought an Atik16ic CCD camera and in 2007- I bought a Nikon D40.
I always use my Atik for long exposure CCD imaging of faint, but also bright, Deep Sky object's.
But, until very recently, I have started to do some test's, to see how good my Nikon D40 compares, for Deep Sky, astro imaging, to the Atik.
For most people, the preferred camera of choice for this sort of work. Are camera's from the Canon stable.
Canon offer a very good range of DSLR's which all have, very good red sensitivity.
So naturally, these were the camera's of choice for imaging nebulae, together with other, fine DSO objects.
There first camera, being, the 350D followed later by the 1000D.
Nikon, on the other hand are not as popular, with digital astro imagers. But over the past year they have started to produce some very good camera's that are suitable, for this type of low light, imaging.
The Nikon D7000 is a very good example. But for some, this camera is expensive.
The Nikon D40 is a 6.1 mega pixel camera, that I use for day time shooting. And until very recently night time, astro imaging.
I am using this camera with an Orion Optics SPX 254mm F4.8 Newtonian reflector, with 1/10th wave optics.
This set up is all mounted on what I consider to be. One of the best value equatorial mount's affordable.
The Losmandy G11, fitted with Gemini Level 4 GOTO.
On Friday September 30th 2011, I was very fortunate to be able to image the night sky from by back garden observatory here in East Cheshire, using this equipment.
And for the very first time. I was able to use my Nikon D40.
Searching the internet, I have found very little imaging of the night sky done with this camera. And I wanted to see, just how good it was. Both for color response, but also sensitivity, to low light imaging.
My subject on Friday was the famous Dumbbell nebula or Messier 27.
During early autumn evening's. M27 is still at the zenith, and crosses the meridian shortly before 9pm, so it is there for, very well placed for imaging.
I was able to set my equipment up in reasonable time, to give the OTA plenty of time to cool down. The mount was polar aligned during the early evening, and whilst it was still light. I was able to go through my alignment procedure.
After spending a quarter of an hour. I was finally ready.
The skies above me were very clear, getting slowly darker. I was able to take some test shot's of Sadar (Gamma Cygni) to check for focus, and tracking issue's. I wasn't guiding, as I do not as yet have a suitable guiding scope.
Everything was looking OK. So with heavy heart I slewed the 10” and D40 onto Messier 27. And began taking 10 x120 second exposure's.
To avoid any vibration's, that could spoil each image. I used the self timer, and also a pillow case that I draped over the front of the OTA .
Film user's will remember the “Top Hat” method, where you cover the front objective, and wait for any vibration's to die down before removal.
This I did. And I was very happy with the raw, image's.
These image's were all stacked in Deep Sky Stacker, with final processing done in PS.
I am very pleased with the result considering my exposure's are all unguided.
And. I am also very pleased to see, how much detail, in M27 I was able to capture using this camera UN-modded.
Paul A Brierley
October 03rd 2011.
I find the taking of CCD image's a big challenge, and with every image taken. I learn something new
