Re: [APML] Tech Pan/Ha filter focusing

["John C. Mirtle" <spampit@shaw.ca>]

----- Original Message -----
From: "Jim Janusz" <jjanusz@dc.rr.com>


<- snip ->
some type of scale on the instrument.  See John Mirtle's page for a great
article on this.

http://members.shaw.ca/jmirtle/ha.htm?

Thanks for the plug Jim! Due to deluges of SPAM I am changing url's and mail
accounts right now. The H-alpha article is now at
http://members.shaw.ca/astrophoto/ha.htm I don't know how much this will
help you Scott, it's a very different animal when you put the filter INSIDE
the optical path, especially with a refractive system. I would think that
some kind of graduated scale might do the job, but you will probably have to
calibrate it against temperature with the longer tube.

John Mirtle
Calgary, Ab. Canada

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