Re: Anyone shoot the eclipse?

Roger N. Clark (change username to rnclark) wrote:
Steve wrote:

I guess what started this confusion is a mis-communication. When Paul
said:

Another route is to align & stack several short consecutive photos, the rotation of the moon will blur at some point too.

Paul is correct.

Well it seems I was mistaken about "the rotation of the moon will blur at some point too." the video clip shows this rotation (moon spinning like a frisbee) but it's only a few degrees over several hours so not really relevant for this discussion. Also worth noting is that a non-eclipsed moon reflects enough light that none of this is an issue, it's only when the moon is dark that you need exposures so long that the earth's rotation blurs the shot, or maybe if shooting at f/32.


I thought he actually meant the rotation of the moon will blur. That's
not correct. The rotation of the moon does not cause any blur because
the moon's rotation is at the same rate as it's orbit. If the moon's
rotation were significantly different than it's orbit (as it was many
many moons ago) you could not get a blur free full image of the moon
no matter what you did.

Didn't you read my last post (the one your are replying to)?
I calculated the rotation of the moon over a 3 minute period
RELATIVE TO THE LOCAL HORIZON, which is also also with respect
to camera tripod axes.

The Chris' post tried to clarify further saying it is relative.

Imaging and stacking many frames of the planets, especially Jupiter
(with its approximately 10-hour rotation period) must be done quickly,
within a few minutes or rotation does cause blur. Amateur astronomers
take video clips of planets at high magnification and stack the frames
producing stunning images with small telescopes, better than could be
done by large professional observatories a few years ago.

What he meant to say (and what I now see is what you understood him to
say) is that the rotation of the earth causes the apparent orientation
of the moon from earth to rotate. That, as you said, can be easily
fixed by aligning the rotation of the images when stacking.

That's what I said and understood Paul to say from the start, and his
posted video clip illustrated that very clearly:

Roger N. Clark (change username to rnclark) wrote Feb 24:
> The moon rotates in the sky with the rotation of the earth.
> From our point of view on the earth, the moon rotates as it moves
> across the sky with respect to our local horizon.

Paul Furman wrote:
> Here's a time lapse someone did of the recent eclipse which shows a
> small amount of rotation of the surface of the moon:
> http://www.maniacworld.com/Feb-20th-Lunar-Eclipse-Timelapse.html
.

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