[AZ-Observing] Jupiter In Good Seeing Technical Details
- From: Tom Polakis <tpolakis@xxxxxxx>
- To: AZ-Observing@xxxxxxxxxxxxx, evac@xxxxxxxxxxxxxx
- Date: Thu, 17 Nov 2011 14:11:48 -0500
Here's the technical data for the image of Jupiter. I didn't do anything
different with this image. All that matters is seeing conditions, which were
arcsecond or better in the back yard last night. And I'll say it again --
stars were twinkling away last night, once again demonstrating how unrelated
visual scintillation is to seeing through the telescope.
Scope: 10" f/5.5 Newtonian with Spooner mirror and Schwar structure (the only
scope with those specs -- Pierre offered to refigure the mirror, but I
declined). This is a Dob on a platform. Tracking is fine, but I wouldn't
recommend this method of centering an object on a chip with a field of view
that's only a couple arcminutes on a side. Better to use something with
slewing controls; unfortunately, my 11" SCT can't do what the Newtonian does
optically.
Camera: Imaging Source DMK series monochrome 640x480. Shoots up to 60 fps, but
this produces severe 'onion ring' artifacts, so I shoot at 30 fps, which still
creates them subtly. I use a manual Orion 5-position filter wheel, and
dichroic R, G, and B filters from Adirondack. I shoot 1000 frames in each
color. Anything longer than a couple minutes results in smear due to Jupiter's
rotation, so you have to align the three color channels on a central feature,
and live with removing the red and blue opposing limbs.
Tom
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