M101 - The Pinwheel

M101 is a spiral galaxy in Ursa Major. Located approximately 24 million light years away, it measures 170,000 light years across. Fortunately, it lies face-on towards us revelaing it's true glory. Considering the size and relatively close proximity of the galaxy, it appears as one of the largest galaxies in the night sky, occupying an area just shy of a full moon. As a result, it's magnitude of 7.2 is spread over a large area making it harder to see.

Below is an attempt at imaging it last night. However, I'm not overly happy with the image as I was limited with the number of expsoures I could capture due to the onset of dawn. I only had the camera operating at -18 as well, resulting in a little more noise than I would like. Therefore, I only got just over an hour's worth of exposures. Longer exposures and more of them set against a dark sky would really show up the fainter outer arms and do this galaxy justice.
Equipment: TEC 140; SBIG ST-8, Gemini Observatory +



Regards,

Nothing wrong with that mate. Even with the 12" you would struggle to get the finer detail especially with lighter skies. I have always found this one a complete nightmare to image.

Much better than any of my M101's...

Looks like the TEC could be a performer given the right conditions. What were your subs? And what calibrations did you do?

Dave

I have to say that looks very excellent to me Michael. Heck, it's only a few years ago that this was as good as the best that Palomar could do!

Clear skies,

Paul.

Fine Image Michael. Nice to see someone doing DSO's at this time of year. Some nice detail in there.

Was that guided with the SBIG?

Thanks lads.

I used 9 x 3mins + 5 x 4mins, so actually, now that my brain is awake again, it's only 47mins of exposures (and not over an hour's worth like I said earlier). I had taken over an hour's worth, but the last few were washed out with the onset of dawn so didn't use them in the composition of this image. I didn't take any darks, flats or bias frames - I generally don't.

I recently raised the height of the pillar in the observatory to compensate for the changeover from the 12" to the 5.5". Consequently, my polar alignment is waayy off. As a result I had the guider fighting tooth 'n nail to keep the expsiures some way right. Thought the image would be far worse - thank god for autoguiders! As we haven't had a clear night in ages, I didn't want to spend the night simply polar aligning. In fact, I spent most of the evening observing Jupiter and the Moon, with the remaining hour or so on imaging.

In terms of processing, I removed the hot pixels and blooming in Maxim. Then, I combined the images with Auto Star Match and Sigma Clip. The resultant image was then brought into Photoshop where the curves were tweaked, black point set, galaxy sharpened, background smoothened, image sized down and then output in jpg format.

Cheers,