Quote:
Originally Posted by casstony
The 9.25 should be close; my XLT C11 is brighter than the GSO 10" dob I had previously.
eg. From my light polluted backyard the area around Carina is filled with nebulosity through the C11, whereas the 10" showed just the brightest parts of the nebula.
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Hi Tony,
That could be because the "out of the box" baffling on the C11 is way better than the 10" GSO and Synta dobs. I baffled my 10" GSO dob many years ago by fully flocking the tube, and installing annular knife edge baffles just above the primary and either side of the focuser. This improved contrast and the scopes performance conservatively by 25%. The black paint used on the inside of the Synta and GSO dobs actually bounces an enormous amount of light around. On top of that, the focuser is too close to the front of the tube and allows stray light to enter the focuser, hence the knife edge baffles. I also baffled the focuser.
Out of the box the 10" GSO and Synta dobs aren't a true indication of how deep you can go with a good 10" newtonian from dark skies. With a bit of simple modification they improve dramatically.
Some photos of my 10" scope attached.
Cheers,
John B