Who has a time-lapsed
lunar eclipse? (1/16/2009). My
year began with an interesting request. A filmmaker working on a PBS project
asked if I had images that could be used to put together a
time-lapse film of a total lunar eclipse.
He'd seen my photo of the stages
of total lunar eclipse from 2003 on NASA's APOD site and got in touch in
the reasonable
(but erroneous) belief that I probably had additional
images from that event that could be melded into such a film. No, I don't,
but I did have a sequence from 2007 that might work, I said. For the August
2007
eclipse, I tried to shoot a uniform series of frames 30 seconds apart.
It didn't work out very well owing to clouds of varying density and because
it was
tough to settle on one exposure that would work for the entire event. If
I ever try it again,
I'll shoot a widely bracketted burst every 30 seconds rather than one frame
every 30 seconds. And I'll use an intervalometer rather than my wristwatch.
And I won't take the camera off the telescope until the eclipse is over
no matter how convinced I am that the sky is about to close the show with
fog, or clouds, or rain.
So you see what I was dealing with: images
of differering exposure and orientation, with gaps owing to clouds. Here are a few sample images.
After aligning
the images and rotating the Moon to the same orientation in all frames,
I used a $20 piece of shareware to meld them into a short time-lapse sequence
with single frame fades between successive images. The last couple of
images are lingered over to let you see the totally eclipsed Moon before
the clip recycles. This is not intended to do anything except demonstrate
that there are enough images here to produce a smooth time lapse (and
be kind of fun to watch). Software with a few more zeroes in its price
(or a lot more time with the tools I have here)
would make a big difference in lots of ways in turning this into broadcast
quality video.
[Clips removed -- will replace with FLV ASAP]
The 2007 eclipse ended with the sky brightening
and the still-totally eclipsed Moon falling into the wooded western horizon:
[Clips removed -- will replace with FLV ASAP]
I got curious about how well I could normalize
the exposures by layering a master shot of the Moon made just prior to
umbral contact under each exposure of a partial phase and then adjusting
the curves, levels, and alpha
values of the top layer. I think the finished results could be very good,
but since the sequence isn't long enough in any case, I'll forego trying
to do
that for the time being. Here are some of the frames from what I call the
normalized
sequence:
Promising even if not ready for Hollywood.
So. Do YOU have the images the PBS filmmaker
needs? The sequence needs to run from the beginning of the partial phases,
through totality, and then on to the end of the second partial phases.
The finished clip will run only 6-7 seconds. At a guess, one frame a minute
should be plenty. Drop me a line and I'll send along your contact information: davidcortner@pobox.com. [UPDATE: producers have
decided to use an alternate sequence; too much post-production required to come up with
a useful lunar eclipse animation.]
