Actually, any lens is fine for astophotography. As the lenses get longer, you
have to guide the exposures though by using some sort of polar-aligned mount if
you don't want star trails. The most common method is to mount the lens on top
of a larger telescope and use the telescope's clock drive. The hassle is that
you typically have to keep your eye glued to an illuminated crosshair eyepiece
for the whole esposure, as almost all clock drives have errors in them and have
to be corrected manually, using a four-way paddle controller. If you have
spare cash, you can attach a CCD to the telescope and buy auto-guiding
software, which will do this for you, but at a significant cost.
The fast telephotos like the 180/2, 300/2.8, etc are great for this "piggyback"
photography, as they grab a lot of light quickly. The downside is that most
lenses have coma at their outer edges, turning the star images into little fan
shapes.
Skip
>
>Subject: Re: [OM] Asro photography with a 300mm Tamron f2.8. # 2977457701, ebay
> From: NSURIT@xxxxxxx
> Date: Mon, 5 Jan 2004 18:46:15 EST
> To: olympus@xxxxxxxxxxxxxxx
>
>In a message dated 1/5/2004 3:37:31 PM Central Standard Time,
>om2@xxxxxxxxxxxxxxxx writes:
>With proper technique, that lens should produce exemplerory astronomical
>images.
>
>I stand corrected. It just never occurred to me that a 300mm lens (6X) would
>be useful for astronomical images, when I often find it too short for my
>nature and wildlife subjects. This old dog sure learned something today . . .
>and
>so early in the new year. Bill Barber
>
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