Re: [APML] Focusing with KEF and Diagonal?

["Kevin Wigell" <kwemail@twcny.rr.com>]

Kent Kirkley wrote:
> 
> Kevin:
> That is correct.
> I'm not sure what you mean by "cover the entire mirror"?
> Yes, the Hutech KEF appears silvery like a mirror, but that's just the vacuum 
> deposited metal that is the knife edge. When using the KEF you are really 
> looking through the central hole......with the KEF surrounding it.
> You should see a 'disk of light' when looking thru it and it doesn't really 
> matter how close to the "eyepiece" you are.
> 

Hi Kent, thanks for the information. What I meant by "cover the entire mirror" was that I was used to seeing the disk of light (the out-of-focus star image) cover the entire primary mirror of my SCT. What I'm used to seeing is the entire primary "lit up", of course with a hole in the center, since it's an SCT.

When I put the adapter and diagonal on the KEF, the disk of light became much smaller and only covered a portion of the primary mirror.

If you are used to using a KEF with a refractor, I'm sure the view of the disk of light appears different - no central obstruction for one thing. I'm guessing you just see a circular disk, not a "donut", as I'm used to seeing.

Kevin Wigell
www.kwastronomy.com



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