5" Meade on the cheep

Started by qbose, 11/05/2003 06:26AM
Posted 11/05/2003 06:26AM Opening Post
Here is a 5" Meade mirror in a 7.75" sono tube with a 1.5" secondary flocked tube and the Matrix Reloaded, 2" focuser and you can see M45 in the entire field of view with a 35 mm 2" EP. Mounts to a CG-5 with a dovetail held by super long "hose clamps." Cost in materials under $100, cost in time ... way more but fun. I guessed at the focal length for the secondary distance between the primary mirror and I have a double image of Mars, is it too long or too short? This is F8 5" and the distance I used is 35" (primary to secondary in tube) and focuser is racked out almost to the limit to achieve focus. I know f8 at 5" is 40" but the original Meade 5" newt was listed at 38" overall length so I figured 2 to 3 inches less than the overall original length as most secondary are recessed in the tube.
Anybody know what the solution is to the double image.
P.S. The seconday is from a 4.5" el cheap o Bushnell (awaiting original Meade seconday).

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qbose's attachment for post 10527
Posted 11/05/2003 07:20AM #1
Actually the double image may be caused by the secondary mirror being mounted with hard glue to the plate. Did you use epoxy or RTV to attach it? I had a double image because of this when viewing Mars. There was also astigmatism induced, do you show any astigmatism in the image?
Floyd

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Amateur Imager