Jump to content


Messier 31 Andromeda widefield


The sky over Lowestoft in the early hours of 25-09-2014 was absolutely perfect for astronomy. After so many cloudy nights I spent a wonderful four hours gazing and snapping. This image is a stack of 15x30second lights at ISO 1600. They were taken using my Canon 400D DSLR with EOS telephoto lens at f=215mm. The camera was mounted on my driven equatorial mount. All combined and messed about with DeepSkyStacker and APS.

  • Like 1

From the album:

Backyard Astronomy

· 143 images
  • 143 images
  • 31 image comments

Recommended Comments

I've been using this galaxy just recently as a test subject for my new (five weeks) rig because it is so open and nearly crosses the zenith in my neck of the woods here in eastern Ontario, but the 900mm focal ratio on my SkyWatcher 100mm, even with the .85x reducer/flattener, means only the core (pretty much just the bright area (white and greenish)  that shows in this image) is visible in the field of view. The data you've accumulated for this (15x30s) tells me that you are using the exposure limit of the DSLR alone, if my Canon T6i is any indication, without any other software or a programmable shutter release, the same as I am doing, but still your image shows much more detail than I am getting from the core area after stacking several dozen images taken with the same settings (I've tried both 800 and 1600iso), though in my case through the 100mm scope, and even with a camera clip-in IDAS LPS filter, and 10-15 flats, darks and bias frames added. In short, I believe I'm doing correctly everything I've learned up to this point. This photo has made me think that perhaps I am using the wrong test subject, or at least with equipment better suited for other test objects, and I will try using the DSLR with my 250mm lens alone mounted on top of the scope and see how my results compare to yours. 

Also, if I'm not mistaken, I see that your stars are just beginning to trail(?), which suggests to me that you are guiding with perhaps only the mount, and not with any software (PHD2, for example)? I am using PHD2 and my stars after 30s are fine, but still the data is not coming in as I expected.

It's all too new to me to get a handle on what's really causing my lack of data, as I've only had the rig up and running for testing for a couple of weeks but the weather has not cooperated and I've really only had maybe four partial evenings to try figuring this all out. 

So much to learn!

Thanks for listening, if you've made it this far, and I don't expect an answer as I haven't really asked more than a rhetorical question or two, but this helps to work things through in my mind, and I will definitely try to duplicate your set up and see what I get.


Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.