Posts Tagged ‘that’

Watching Sunset on the Moon, and things that go bump in the night!

August 20, 2011

Well it’s a start.  Sunset on the Moon!

This is the time lapse of sunset on the moon, taken at prime focus with a cpc11 with a focal reducer and a canon 60D.  The conditions were less than perfect.  This was about 9 hrs all in, and really quite an infuriating 9 hrs.

Firstly, since my ‘run in’ with the mountain lion, I’ve become VERY twitchy about things that go bump in the night, and would periodically scan the torch around, looking for ‘eyes’.  There was also an amusing part when a piece of paper blew out of the car.  The ‘sudden noise’ in the dark elicited an immediate reaction from me, which to the impartial observer must have appeared quite funny and disproportionate! (twirling around ready to attack the piece of paper…… hmmmm….  time to switch to decaf!)

Not all bad though, amazing what the heightened senses can find!


For some reason the telescope is lousy at tracking the moon.  I think this is to do with the fact that the Earth axis, and the normal of the orbit of the moon are out by about 6 degrees.  Practically what this means is the moon not only moves at a different rate to the stars (that is it goes around the sky in about 25 hours, not 24 like pretty much everything else).  But even with lunar rate, the tracking is poor.  I think the moon is also moving up/ down due to the difference in the normal of the Earth rotation and the moons orbit, and the mount is not smart enough to work this out.  The practical upshot of which is the moon will drift out of the field of view over a period of about an hour, so I had to set the alarm to go off every 20 minutes throughout the night in order to recenter the moon.

Further recentering the frames, taken every 2 minutes in editing is also a pain in the ass.  Thankfully Sony Vegas now has a ‘motion stabilizer’ feature that takes a lot of the donkey work out of this.

This is the finished product!  Well actually, only part of it.  At prime focus the telescope can get the best part of the moon in the frame.  I just selected one crater, as it shows the shadows nicely.

Tracking on everything else is perfect, in that at the end of the evening I dialed up Jupiter, and it went straight to it.  Cute! Never seen Jupiter by the full light of day before!


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