Yes, I know!!

Yes, I know, there is no real difference between  the original and ‘improved’ image of Saturn.  Every one’s told me and I can only agree.

I have been searching for clues as to why my images are worse than those obtained by others using much the same equipment.  The most likely culprit is poor collimation of the telescope optics.  Put simply it ensures that the two mirrors are accurately aligned.  Apparently this is a simple adjustment which should be checked every time the telescope is used.  Next time the weather is kind I will see what can be done.  If better images result I will, of course, put them on the blog and boast a little.

Improved photo of Saturn

I’ve been trying to improve the image of Saturn.  I use a program called Registax with which it is possible to selectively sharpen the image and adjust contrast and brightness.  The image below is the result of applying Registax’s image improvement features.

Registax was specially written for astronomical imaging.  It accepts individual .jpg images or .avi video consisting of hundreds of frames.  The first run through of the program sifts out the best images and ignores the unusable images.  An area of the image is then defined and a second run through ensures that all the images are aligned.  This is necessary because astronomical imaging is subject to atmospheric effects – the twinkling star effect – which blurs the image.

The sorted and aligned images are then stacked.  This is a statistical averaging procedure which doesn’t increase the brightness but is utilised to eliminate random noise.  The final operation is to sharpen the image to bring out the fine detail.  Sharpening is achieved by adjusting wavelets – no, I don’t understand what they are either – but it is surprising what can be achieved.  Finally the brightness and contrast are adjusted.

The image above probably represents the best I can achieve with my modified webcam.  My next target will be the moon.  This will have different problems because the camera cannot get the whole of the moon in one shot.  Apparently the technique is to take several images covering the whole of the moon and then using a program which ’stitches’ them together.  Watch this space!