GSO Carbon Imaging Newtonians - Anyone got one?

[hrcoleman66 (Hugh)]

Hi all,


I keep drooling over these at Testar.
https://www.testar.com.au/collections/gso-newtonian


Basically standard GSO newtonian optics (Which are not bad) in a carbon tube with upgraded CNC machined Spider, upgraded Primary Cell, upsized secondary, linear bearing Crayford focuser (The Stela Lira version has a rack and pinion focuser) and CNC machined rings and losmandy plate.


I reckon the added extras come to about a grand.
Carbon Tube is about 250.00 on ali express
A 2" RP focuser can be got from Ali for about 280.00 (I got a nice one for my 6" RC there).
The machined rings, spider and Primary Cell probably come in at around 250.00.


If anyone has the 6 or 8 inch versions, I'd be interested to know what your experience is like for imaging with them. I know from the Web that people have had bad experiences with the 4.5" one trying to achieve focus with the recommended Coma Corrector.


Cheers,


Hugh

[Startrek (Martin)]

Been using 6” , 8” , 10” and 12” Newts for years
Built my own Carbon 8” and 10” back in early 2022 using a Klaus Helmerich blank Carbon tube and GSO parts.
By the way mine are all f5’s
8” cost me around $1250 and the 10” cost me around $1500 nearly 3 years ago
I’d never touch an f4 as too many folk have had issues with entry level f4’s. In fact there’s a current post about this very issue. If I was ever going f4 it would be high end premium commercial stuff.

The 8” sits on a SW EQ6-R pro mount ( guiding around 0.40 to 0.50 ) top mount a real workhorse

The 10” sits on a SW EQ8- R pro mount ( overkill ) guiding around 0.50 to 0.70 ) these mounts have inherent backlash and hard to tune out.

Imaging cameras ZWO2600MC ( not used much these days )
Use mainly my ZWO2600MM with Antlia LRGB pro and Antlia Ha Oiii and Sii 3nm filters

The benefits of f4 compared to f5 are minimal ( the camera does all the work )
Image scales are 0.77 arcsec per pixel for the 8” and 0.62 arcsec per pixel for the 10” so oversampling gives me plenty of flexibility in processing

My subs in Sydney under B8 skies are generally 20 to 30 sec for Broadband and 120 sec to 180 sec for Narrowband
Down at my Dome subs for Broadband are 60 sec to 120 sec
Narrowband between 90 sec to 120 sec

My 8” Carbon newt images under B8 heavy LP in Sydney
My 10” Carbon newt images under dark B3 skies in my Dome on the south coast NSW.

Both hold collimation really well ( only check it once in a while but it’s normally fine every time I check )

My images are on Astrobin

Clear Skies
Martin

[rmuhlack (Richard)]

If I was in the market for another imaging newtonian I would be seriously considering one of these. I've previously owned a GSO 200mm f4 imaging newtonian (steel tube) and that was very good (and I was able to achieve focus with both a Baader Type 2 MPCC and a Televue Paracorr coma corrector). I think the carbon tube, upgraded focuser and solid spider would make this new Testar offering very compelling.

Collimation is more challenging at f4 than f5 however - which is what i'm using now for my larger scope - a Skywatcher 200PDS with upgraded solid spider, primary mirror ring and a Moonlite large format focuser with ultra high resolution stepper. All up those upgrades were considerably more expensive than the new GSO 200mm scope from Testar (and its much heavier than the GSO too), so if I was doing it all again i'd be very tempted by the GSO.