6 inch imaging Newtonian choices?

Equipment Reflectors Buying Advice
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Eren avatar
Eren avatar

First off, thank you all for your help with my selection in cameras. I went for the mono Touptek 585M and I am very happy with it so far. It pairs nicely with my Zenithstar 61.

For some time I’ve been thinking about getting a Reflector as my second (actually third scope since I had an 8 inch Dobsonian which I’ve sold recently) scope. And it will most likely be a 6 inch newtonian, which would sample perfectly with my camera. I also thought about an 8 inch one, but I’m unsure about that. My mount could handle it well if I get counterweights for it, though.

My primary choice so far is the GSO 6” f/4 which comes pretty well equipped with a Monorail Crayford focuser. I’m not sure about the Skywatcher scopes since I’ve heard mediocre reviews about it. Any other recommendations? And does anyone have experience with the GSO scopes? As for collimation, so far I’ve used a laser collimator with my dobsonian but I haven’t collimated the scope more than two times, so I’m still quite experienced in that area. I’ve heard that the OCAL camera helps a lot but could I use my ASI 120mm guide camera for that too?

Thank you for your help!

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andrea tasselli avatar
andrea tasselli avatar

First off, a GTi would NOT handle a 6” f/4 newt, if that is what you have. GSO optics are OK with few lemons here and there. Be prepared for some TLC to get a performer notably with the primary cell being quite flaky and frankly I would shy away from a monorail, too many issues with tensioning in variable temperatures. Go for a R&P focuser. My choice would be either a high performance high quality newt such as the Alpha or this one for a smaller budget: StellaLyra 6" f/4 M-LRN-D Carbon Fibre Imaging Newtonian Reflector with 2" Dual-Speed R&P Focuser | First Light Optics

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Eren avatar
Eren avatar

Thank you for your help!

I changed to a Juwei/Teseek 17 because the GTi couldn’t hold my refractor rig.. Would the monorail be a problem even with an EAF? And also, what are some of the major advantages of a carbon tube?

andrea tasselli avatar
andrea tasselli avatar

Yes, it would be a problem especially with an EAF. Carbon tube brings you lower thermal expansion (not that you really need it with a short 6” but good to have nonetheless) and much higher stiffness with the same weight. I don’t have one yet but I’m gunning for the 8” instead.

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Eren avatar
Eren avatar

andrea tasselli · Apr 19, 2026, 07:40 PM

Yes, it would be a problem especially with an EAF. Carbon tube brings you lower thermal expansion (not that you really need it with a short 6” but good to have nonetheless) and much higher stiffness with the same weight. I don’t have one yet but I’m gunning for the 8” instead.

The StellaLyra seems like a perfect choice, importing it to the EU would cost me 2,5x the price of the GSO though 😅 I could get the GSO 6” with a Baader coma corrector and a new R&P focuser for that price. There are TS Optics variants here but those are basically just GSO rebrands for double the price.

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andrea tasselli avatar
andrea tasselli avatar

This is the equivalent of the StellaLyra, in the EU (Italy). I now the guy and I can recommend them: Astrografo Newton 150/600 Tecnosky CARBON Series

andrea tasselli avatar
andrea tasselli avatar

Incidentally, you’d need a better coma corrector than the Baader one.

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Tony Gondola avatar
Tony Gondola avatar

I have a GSO 6” F/6 newt with the Crayford focuser. I also have a mono 585. I went with the F/6 because paired with the 585, you can very much live without a coma corrector. That simplifies things somewhat with no worries about back focus. On the focuser, I could certainly benefit from something more capable but the Crayford works. My EAF is attached to the tube so that can be made to work as well with a bit ingenuity.

Mine might be a fluke but the primary is excellent. It’s better than 1/10th wave on the bench. I use the OTA at both the native F/6 and also in conjunction with a 2” ED Barlow which gets me out to 1580mm F/10.4. The only modification I’ve made is a 3d printed mirror mask to clean up the diffraction around brighter stars. Lastly, I’ve not had any problems or difficulty in collimation. You certainly don’t need any special tools or cameras to do it. I carry the scope in and out to the backyard for sessions and I haven’t had to touch the collimation knobs for over a year now.

Mine might be a one-off fluke but I’m getting a lot of performance for very little money spent and few modifications made.

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Dan Watt avatar
Dan Watt avatar

I’d get the cheapest used 6” f4 you can get your hands on and upgrade it from there with a cnc spider and mirror mask. All of the 6” options on the market have the same 6” GSO mirrors that have varying degrees of issues. Maybe 1 out of 10 is actually decent. The Synta mirrors I’ve tested aren’t really any better. The biggest issue is surface roughness which will result in flaring with bright stars.

The Baader Steeltrack is the only 2” style focuser I’d consider if you want to be able to use threaded connections or add stuff like a rotator down the line.

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