Whirlpool Galaxy, M51 – 22nd April 2015
Imaging time is getting scarce these days with the sun setting later and later as we head into summer. There are fewer and fewer hours of decent darkness these night but I had to take advantage of a few clear nights and have a go at the spiral Whirlpool Galaxy (M51) which is around 23 million light years away. Not the furthest target I have attempted, but still a very distant and faint galaxy.
The above is a composite of 29 x 2 minute exposures along with the usual calibration frames. I did start with 40 shots, but satellites ruined a few and periodic errors in the gearing meant some of the other images had trailing stars. You can still use them, but the stacking software struggles to pull them all together and produce perfect stars in the final image. There is the tiniest evidence of trailing in the above image, but I think it has come out quite nicely considering the mount is pretty much working at its limit.
And, just to put it into perspective, in relation to the sensor size in the camera and the field of view it gives, I thought I would also post one of the original light frames, just to show how small the target is when looking for it. And, don’t forget, they are invisible until you take a photo.
You should just be able to see the core of the galaxy just right of centre in the picture? Which just shows how much of the original picture needs to be cropped out to get to the first image. This scaling can be improved with more advanced, dedicated CCD Astro Cameras with smaller sensors, but I need to save up a bit for one of those!
I’ll put a higher resolution copy of the first image in the Gallery.
Thanks for looking!