I am looking at the web site at this URL: http://www.astrocruise.com/geg.htm
talking about the advantages / disadvantages of the Lumicon GEG and
Astrophotography with a regular 35mm camera.

I'm in the Vignetting section and I'm trying to figure out what Vignetting
is. There is a section on the author of this WebPages's sections stating he
is using a 10" LX200 (F/10) just like I have, so I'm reading away.

Now the vignetting with the Meade / Celestron focal reducer is somewhat
obvious, if I understand what it is. There is a whole bunch of space
missing around the image, looks like tunnel vision.

On the Lumicon pictures, at F/10, F/6.5, F/5.5, and F/4 I can't see any
black rings around the images that are as obvious as the Meade/Celestron
image.

Is this the point that the author is trying to make or am I blind staring
into my 17" monitor at 1024x768 and just not seeing anything?

Also, did I misread a book I have and Vignetting isn't the 'flattening' of a
star into a streak?

If I ever get to CCD imaging will the Meade 6.3 Reducer produce such a broad
vignetting that shows up on this image on his page? Or is the chip so small
on the camera (ST7 for example) that it can't get the full cone of light a
35MM camera has and so you don't need to worry about it?

If an ST7 and a Meade 6.3 are compatible, then is the GEG's advantages
really only there for 35mm or medium format camera astrophotography, or am I
off base entirely?

Thanks for your input.

Tom Boucher

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