One of the problems ecountered in using CCDInspector for collimating scopes is there is often a lack of a sufficient number of stars available to create an image with enough stars for analysis by CCDInspector. Has anyone tried to make an artificial star mask consisting of a piece of dark construction paper (or whatever) into which an array of pinholes has been punched. By placing this mask over the objective of the scope and illuminating it from behind, it seems as this would similate a star field suitable for analysis by CCDInspector. I thought about making such a mask and using my flat fielding box to illuminate it. Any comments?

Regards,
Rick Davis

Hi Rick,

As with any other "artificial star", you'll need the star images to be generated at close to infinity focus. The source of light and the mask must be located reasonably far away from the telescope. The larger the diameter of your objective, and the faster the F/ratio, the farther away it should be.

What's worse, since the mask is not really, REALLY far away, the star sizes and shapes generated by the mask will have to be all very nearly the same. If not, it will confuse CCDInspector collimation routine.

So, if you can find a way to create a large number of equally-sized and equally-shaped, tiny light sources near inifinity focus, then you'll have an artifical star field you can use for collimation. Unfortunately, I don't know of a way to do this...

Regards,

-Paul

Paul,

Thanks for the response. I had a feeling that if this was such of a good idea there would have been more discussion about this technique on this forum. I guess I will have to wait until I get another clear night to try again using real stars.

Rick