(meteorobs) Geminids from Greece

Chris Peterson clp at alumni.caltech.edu
Mon Dec 15 18:22:40 EST 2008


I'd strongly advise against using a reflector. Good CS-mount fisheye lenses 
are quite inexpensive, and have huge advantages. In particular, it is nearly 
impossible to accurately determine the position of a meteor in the sky with 
a reflector, because they don't have well controlled surfaces. That's not a 
problem with a lens, which can be astrometrically calibrated. If you plan on 
doing multistation work, with the intent of recovering meteorites or 
recovering orbits, convex mirror systems really make things difficult.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "stange" <stange34 at sbcglobal.net>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: Monday, December 15, 2008 11:48 AM
Subject: Re: (meteorobs) Geminids from Greece


> Hello J.D.
>
> Sounds like you purchased a JBD CB-23803(S?) 1/3" CCD B/W camera with 
> 0.003
> Lux rating. Using the camera with the zoom lens will confine the field of
> view(FOV) into a rectangular shape. Lowering the zoom to 3.0 will give the
> widest FOV but still rectangular because of the CCD substrate shape.
>
> An "ALL-SKY" option for the future would be to use a highly polished 
> "moon"
> hub-cap from a car, or better yet, a hemispherical mirror dome(the bigger
> the better), with the camera mounted downward over it. Similar 
> construciton
> to what I have illustrated at:
> http://www.geocities.com/stange34@sbcglobal.net/IR_Experiment.html or the
> earlier design used by Chris at Cloudbait Observatory.
>
> If you do go in this "ALL-SKY" mirror direction, the height of the camera
> over the mirror for imaging the entire perimeter of the mirror, will be
> determined by the amount of zoom.
>
> The higher the magnification, the higher will the camera need to be over 
> the
> mirror to get the entire image of the mirror circle which contains a 360
> degree all-sky view.
>
> Most folks try to use around a 4mm adjustment which will keep the camera
> lower but at the expense of slightly larger central obstruction which is 
> the
> image of the camera in the mirror itself.
>
> Using inexpensive ($40 U.S.) programs like Handyavi will give you
> satisfaction in captures.
>
> Try the program for free at their website download to see if your 
> composite
> capture card can work with that program. You may have to experiment a 
> little
> with comuter settings and Handyavi settings. Generally if Windows XP can 
> see
> the mirror image, so will Handyavi.
>
> Good Luck, YCSentinel.




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