The photos in step 4 showed a fair amount of sensor noise. There is a trick to fixing this which one can borrow from amateur astronomers who use webcams to image the moon and planets (like this moon photo that I took using a webcam, Avi Stack and my 8" F/4.5 telescope--more photos here
). Instead of taking a single picture, one takes a short movie containing a number of frames. The ones I did ranged from 30-90 frames (i.e., one to three seconds). Then one uses stacking software to combine the frames into a better image. Good stacking software also allows you to use wavelets to adjust sharpness in pretty sophisticated ways.
I used the free Avi Stack
for stacking (you can also use the also free Registax
), which works on Windows, Mac and Linux. You can capture the video with your webcam's software, but I found that it's better to use wxAstroCapture
, available for Windows and Linux, as my webcam software wanted to produce .mpg files, and then I had to convert them to .avi files with Windows Movie Maker.
So, install Avi Stack (on Windows, you just unzip it into any directory where you want it) and and any video capture software you need. You need to make sure your capture software produces videos in a format Avi Stack can understand. See Section 2.3 of the Avi Stack manual
for supported formats. On Windows, I strongly recommend you follow the instructions in Section 2.3 to install support for additional Windows .avi codecs: go here
, and download the krsgravi.zip
file by unzipping its contents into the directory where Avi Stack got installed.
Once you have all this installed, capture a small .avi segment of your sample with your webcam. Don't worry if there is noise jumping around. Here's an example.