Saturday, December 25, 2010

Timelapse Eclipse

I wasn't sure what to do with all of the pictures of the eclipse so I decided to assemble a timelapse.

Only captured the first half of the event due to clouds.  Crickets just for fun.

What a colossal pain!  There has to be a better way to do this.  Has to.  If someone knows what it is please leave some advice in the comments.  I'll describe what I did just to share the pain.

Going into any imaging session with some clear plans and goals ahead of time will save yourself a world of hurt later.  This is something I almost never do.  I hurt a lot.

If I knew ahead of time I was going to shoot a time lapse sequence I would have set up on a accurate polar aligned mount to save the painful image alignment process later on.  Also I would shoot 2 or 3 exposure times for each segment to dial in the constantly changing light as the moon is eclipsed.  Obviously this doubles or triples the number of exposures but that would have come in handy later on.

I decided to downsample all the images so I would have smaller files to deal with to assemble the movie.  The plan was to go back and do this with the full resolution pictures but it took me so long to do this with the smaller images I just can't bear to do it now ... or ever.  

Now remember my images are drifting all over the frame do to inaccurate polar alignment, re-framing, bumping the mount while checking focus and changing camera conditions.  How to align all these images?  I figured using Photoshop content aware alignment would work ... but alas it only worked on the images from the beginning of the sequence - as the moon went deeper into the eclipse photoshop got confused.  Maybe Registax?  I downloaded and fussed for a while be it was too much to learn without being absolutely sure it would give me what I wanted.

What I wanted was aligned and cropped individual images.  Maybe Registax could do that but I didn't see how. OK.  Back to photoshop.  Time to put on the hair shirt.

Load up all the images (downsized) into separate layers.  Make top layer (full moon) visible - turn off all other layers.  Blend mode difference, opacity 80%.  Make the layer immediately underneath visible and highlight it.  Manually move to align.  Turn off visibility of this just aligned layer. Select visibility of next layer down and highlight.  Align.

Repeat 150 more times.  Yeah.

As you go through toss away the bad ones.  Wrong exposure, clouds, out of focus, whatever. Oh yeah, don't forget to go back and return your blend mode and opacity of the top image to normal.

Then crop the whole mess and then save each layer as a file (at least there is a script in the file menu for that!).   Then load up all of these into iMovie (we don't do Windows in Cilice-land - I am grateful to the axemen for my conversion).  Fiddle, export, be satisfied.  It's not perfect.  Far from it.  Don't think about repeating with higher resolution.  Just *don't* do it.  Not worth it.  Really.  Don't look back.

Now go enjoy your Christmas!

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