Sorry for the cross posting, but I thought this was topical for both groups.
I've been toying with the idea of using the LPI to guide my telescope via
the 8 x 50 finderscope so I could guide the scope during long photographic
exposures using the tel-extender rather than using the off axis guider which
limits me to prime focus alone.
Taking the eyepiece out of the end of the finderscope however, I discovered
that:
1. The LPI is too large to fit in the end of the finderscope
2. It would not be in focus.
However, I think that it would work if I made an adapter that would go
between the two and I new how long the adapter would have to be to bring the
LPI to the focal point.
I'm sure the calculation's an easy one.
Does this sound too ridiculous?

----- Original Message -----
Sent: Tuesday, May 04, 2004 7:56 PM
Subject: [meadelpi] Re: focal reduction in an LPI?


> Sorry Jim,
>
> Can you run that by me one more time..You can reduce the FOV of your
> LPI by shoving a finderscope objective lens up its..tube?
>
> Can you describe that agian..? Maybe a pic or diagram?
>
> Curious Pete..
>
>
> > Guys and Gals.
> >
> > I have 3 LPI's and to get a full disk of the Moon you have to
> reduce the focal length and an easy way I've found, is to get the
> objective out of its cell from a 6x30 finderscope and wrap some
> magic tape around its edge till it fits nicely into a standard
> focuser. Trim the exccessive tape off with a trimming knife, and
> push the lens up into the focuser tube.The distance from the lens
> to the LPI chip is about 2-3" . With a 400mm F5 scope, and this 6x30
> finderscope lens (which is what a telecompressor is) I can get the
> entire lunar disk (see LPIlunar FTP below) on the chip of any video
> camera and most of these, use a 1/3" chip.
> > Anyway, that is my input to this discussion.
> >
> > Jim
> > Director:
> > Nanango TIE QUT Observatory.. www.eese.bee.qut.edu.au/tie
> > Stuart Range Observatory.. www.big.net.au/~cosmos and
> www.big.net.au/~cosmos/gallery/LPIlunar
> > South Burnett - Maidenwell Astronomical Observatory Pty. Ltd.
>
>
>
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