f/stop doesn't matter in star photography since the light is effectively
point source. It's just the aperture width.
tOM
On Sunday, August 11, 2002 at 12:57, Ralf Loi <olympus@xxxxxxxxxxxxxxx>
wrote re "Re: [OM] Zuiko telephoto fro astrop" saying:
>
> My 2 eurocent on this. If you have a setting like the Carlos one, probably
> the 200/4 is a good choice, but if you have a smaller scope for guiding or
> no scope at all (there are automatic tracker that must be carefully
> aligned), my vote is for a shorter lens like the 135/2.8. This lens, being
> one stop faster, permits also to keep the exposure shorter. I used this
> lens for many astropics with very good results, even if the guide was
> performed "by hand" (no motor). Later, if your results are good you can try
> with a more difficult lens like the 300/4.5, which performs very good open
> and is only a third of a stop slower of the 200/4 but 500nger in focal
> lenght.
> In the next days I will hopefully have some time to scan some pics taken
> with the 135/2.8 and to post they.
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tOM Trottier, ICQ:57647974 http://abacurial.com
758 Albert St, Ottawa ON Canada K1R 7V8
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"The moment one gives close attention to anything,
even a blade of grass, it becomes a mysterious,
awesome, indescribably magnificent world in itself --
Henry Miller, 1891-1980
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