Long exposure vs. multiple exposure

From: Steve Maddison (steve_at_cosam.org)
Date: 08/19/04 

Date: Thu, 19 Aug 2004 02:11:26 +0200

Hi all,

I bought a Canon PowerShot S45 digital camera a year or two ago before I
got into astronomy. It's a decent camera, I was thinking of rigging it
up to try my hand at astrophotography.

I've looked through the docs and experimented with long exposures, but
this model only goes up to a maximum of 15 seconds. I was initially a
little disappointed, but then got thinking about using multiple
exposures of 15 seconds (or less) and stacking the images.

Maybe my logic has taken a wrong turn somewhere but, given the accuracy
of your average, run-of-the-mill mount, wouldn't the use of several
images allow some manual correction of tracking errors? Surely there is
some major advantage of a single, longer exposure that I've so far
overlooked? (Apart from the obvious elimination of the stacking process
itself.)

Just wondering,

  Steve

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