Guan Sheng 8" f4 Newt

[garymck (Gary)]

Hi,
does anyone know the size of the secondary mirror in the Guan Sheng 8" f4 Newt (GS 600) as sold by Andrews?

Trying to determine whether it needs a bigger secondary for imaging.

Distance of focal plane from tube would be helpful.

Staff at Andrews don't seem to know much..............

cheers
Gary

[chris lewis]

It has a 63mm Secondary - which is 33% CO. The 8in. F/6 DOB version has a 50mm mirror.
If you run 'Newt software' it may help you determine if a larger secondary is feasable.
I had one for a year as sold by 'Astronz' in NZ - great 'light bucket' - but collimation had to be spot on. Coma noticable but expected in a 'fast' Newt.
The next GSO secondary mirror size up is 70mm which is in there 12 in.

http://www.dalekeller.net/atm/newton...t/newtsoft.htm

http://www.astronomy.co.nz/pub/GS600.asp