sct visual back and diagonal

tungkian · Post by **tungkian** » Fri Jan 12, 2007 10:17 am

can those 2inch SCT adaptors or visual backs (those branded by OPT but made by GSO) fit on the the celestron 6 inch SCT?

i've seen those diagonals made by GSO that says SCT diagonal. do they screw directly to the back of the SCT? will the 6 inch SCT come to focus with such a diagonal?

if i were to use a 2inch visual back and insert a standard 2inch diagonal for refractors, will the SCT come to focus?

hoping for some advice from experienced observers. cheers!

btw, can i also know where i can buy the 2inch visual backs in SG...

kayheem · Post by **kayheem** » Fri Jan 12, 2007 10:30 am

I used to have the 5" SCT which has the standard SCT threads, so I suppose the 6" will have it too. I used a 2" diagonal with SCT thread instead of using a regular diagonal with 2" visual thread.

Having said that, the diagonal with SCT thread (from Antares) is slightly different for the C5 such that it will not obstruct the focusing knob.

rlow · Post by **rlow** » Fri Jan 12, 2007 11:15 am

The 2" visual back from OPT fits C8, should fit C5 & C6 too. I use the WO 2" visual back (you can check with Robin/McGill for this) on my C5 and there is no obstruction due to the focuser knob. Reaching focus with 2" visual back & 2" diagonal is generally not an issue with SCTs.