Re: [APML] Comet Exposure Questions

Thanks Wade. Since I have no way to guide on the comet, how would those times transpose to guiding on a star (prime focus), or for piggyback?

Gary

----- Original Message -----

From: Thomas W. Earle

To: 'Discussion of Film Astrophotography'

Sent: Sunday, January 09, 2005 12:47 PM

Subject: RE: [APML] Comet Exposure Questions

Gary,

It depends on what night your interested in taking pictures since the comet is moving at a different speed each night. Your tolerances for each lens are as follows:

55 mm      94"

105 mm    49"

480 mm    10.7"

As an example, the comet is moving at 5.2"/minute tonight (5/9). Hence, your "maximum" exposure without seeing any drift in the stars, assuming your guiding on the comet, follows:

55 mm     18 minutes

105 mm    9 minutes 30 seconds

480 mm    2 minutes

Wade

From: astro-photo-bounces@seds.org [mailto:astro-photo-bounces@seds.org] On Behalf Of GARY HATFIELD
Sent: Saturday, January 08, 2005 10:23 PM
To: APML
Subject: [APML] Comet Exposure Questions

Can someone give me approx. exposure times for a 55mm, 105mm, and prime focus 480mm/f6 when shooting Comet Machholz without blurring it?

Thanks

Gary
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