Thread: M42
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Old 02-20-2008
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dmill1220 dmill1220 is offline
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Join Date: Sep 2006
Location: Raymond NH
Posts: 370
Hi Dave,

I'm Glad You now have a better way to focus, I use a three hole Hartmann mask, its done a good job so far.

As far as your first Drift star and the Meridian,
Your meridian is an imaginary line directly overhead that runs from the northern horizon all the way to the southern Horizon, it has nothing to do with your location, wherever you are, look straight up that's your meridian. If you live in the northern hemisphere as I do, the celestial Eq is 90 degrees south of the Pole star Polaris.
to stay 5 degrees within your meridian and 5 degrees of the celestial Eq you can use your setting circles. see attached image

Once you have Polaris aligned in your eyepiece, set your declination circle to read 89.5 degrees, the celestial EQ is now at 0 degrees due south on your Dec scale and it extends from the eastern horizon to the western horizon.

Just remember any drift guide star must be within 5 degrees of both.

When you go to adjust the Declination axis find a star as close to the eastern or western horizon within 10 degrees, but keep the declination circle at + or - 5 degrees from 0, remember your moving the telescope in RA only to the east or west.

Dennis
Attached Thumbnails
m42-your-meridian.jpg   m42-declination-setting-eq.jpg  
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Dennis Miller
Raymond NH
12 Celestron Starhopper
10 Celestron Starhopper
6 inch Celestron ASGT refractor
8 inch Celstron SCT
Meade DSI

Last edited by dmill1220; 02-20-2008 at 04:41 PM.
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