For images I've taken with a CCD camera I align, stack and process them using Nebulosity2 which is a cheap and comprehensive processing program available to download for a fee online or if you want it on CD then iankingimaging.com sell copies.

As yet I'm only imaging in black and white so I don't know how you'd merge and process colour images. Once I've got a colour filter wheel and work out what do I'll then update this page.

There are loads of settings in Nebulosity2 that I've no idea about. I only use some basic settings and get some ok results so I'll explain what I do. For this example I'm going to process a number of images of M31 The Andromeda Galaxy into a single image. Once you've loaded the program it looks like this.

Click File on the top left and then Preview Files and a new window will appear.

Hit Load Images and select the images you want to preview.

Once you've selected your images view them by pressing next or previous on the image previewer. You can delete the images you don't want to use or just rename them. I normally delete the bad ones as I'm not going to use them at any point. While I'm viewing the images I leave the Auto Scale box (top right) checked as it'll give you a better chance of seeing the image in its raw form.

Click done when you're ready and then on the top left tool bar hit Batch, then Align and Combine Images which will bring up another window shown below.

I leave the settings alone on the alignment/stacking window and just hit ok. You're then given another window to select the frames you want to use.

You are then given a target cursor that you aim over a star of your choice and left click. I normally try to find a small well defined star to select. You will now see a small red circle around your chosen star. If you've got good eyesight you might be able to see the red circle around a star near the top left corner of the screen in the image below. Hold down the Control button on your keyboard (Ctrl) and left click on the mouse (your mouse cursor does not have to remain over the star as the red cirle has targeted it). This will add the next image to align. Keep the Ctrl button held down and left click until all the images have been added.

Once it's finished you'll be given a new window to save your stacked image. I've saved this as M31 Aligned.

I now uncheck the Auto Scale box top right and move the B slider fully left and the W slider fully right. You need to do this before processing to get a true representation of the final image.

This is where it gets a little experimental as I do a bit of hit and hope until things look ok. Don't forget to save the image as you go along in case you mess it up and want to go back a step. For this image I've started with Digital Development (DDP) which is under the Image tab in the top left toolbar. I normally move the bottom slider to 80 (I read to do that somewhere) and move the middle slider until the main body of red on the histogram (top right) touches the left of the graph. You can also alter the Edge Enhancement to sharpen the image if you like. When I've finished I hit done.

I then click on image again and this time select Levels / Power Stretch.

Again I move the bottom slider to 80 which will alter the histogram graph within the Levels/Power Stretch window. I then move the top slider until the main body on the histogram touches the left of the graph, and the middle slider until the right of the main body touches the right side of the graph. Hit done once you're finished.

Now the image looks like this below.

Next I hit the Image tab again and this time select Curves, and a new window will appear titled Bezier Curves. There are lots of pre-sets you can choose on the right of the window but I just leave it on Reset(Linear).

You will see two blue dots along the diagonal line. Hold the mouse cursor on one of the dots, hold down the left button on the mouse and move the dot. As you move the dot you will see the line move on the graph. When you release the left mouse button the dot will remain where you left it and the change will be applied to your image. Have a play with the dots and see what works for you. For this example I've made one set of adjustments first and you can see how I've altered the graph and then how it's altered the image. Hit done when you're finished.

If you're not quite satisfied with your first set of adjustments then you can select Curves again and make further changes, and so on. I've made a second set of adjustments with curves as seen below.

Once you're happy with your final image you might also want to save it as a jpeg format. Nebulosity2 saves images as fits files by default while you're working with an image. So if you want to save your finished image as a jpeg, which any computer will be able to display, then hit File in the top left toolbar and then Save JPG File as Displayed.

I'm sure someone with more experience and more patience would be able to get a far better result but if you compare the final image to the first one on this page then you should be able to see just what Nebulosity2 is capable of in the hands of an amateur.