Author Topic: 1980 Meade 8" Newt (826) Contrast  (Read 18 times)

David Corder

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1980 Meade 8" Newt (826) Contrast
« on: December 24, 2017, 03:27:10 PM »
I recently picked up a somewhat decrepit 1980 Meade 826 8" Newt about the conventional pier mounted EQ clock push mount.  I cleaned the mirror but it still shows its age since there are a number of places of lost silvering and some overall decay of the face but I believed it was still worth examining.  I compared the perspectives of the Moon, Saturn and Mars through it with an Orion 8" DOB (Intelliscope) and discovered the contrast of the Meade was considerably better.  And I mean considerably.  The black around the Moon was, well, black, whereas with all the Orion there was definate gray.  Same effect with Saturn,  black.  Sharpness was about the same, both excellent.

The specs of both scopes are very similar with the Meade being 1220mm/f6 along with the Celestron being 1200/f5.9.  The sole difference I can see is that the secondary on the Meade is 1.5" and the Orion two".  Both tubes are internally darkened to about the same degree.

Could the secondary dimension account for the that contrast gap?  What other things could have this kind of effect?

Thanks in advance for any and all responses.

Tom Duncan

PS: Trying to work out the specific designation of the scope. . .what is the distinction between an 826 and an 826C?  This one does not have any manual declination knob (see picture).  Attached Thumbnails