Attaching ZWO Filter Holder & ASI2600MC to an RC 8" Focuser - Forums

Topic starter

Frequent contributor

Mar 19, 2024

HI,

When I look at photos of the RC 8" by TS Optics, the focuser appears to have screws rather than threads. How would I attach a threaded filter holder and camera (and threaded adapters) to this telescope without having to replace the focuser?

Thanks,
Jerry

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Johannes Maximilian Möslein

Mar 19, 2024

Hi Jerry,

I have that scope. I just insert the front of my imaging train into the focuser and tighten the screws. If the first point of your imaging train is a thread, you probably need an adapter that you can insert into the focuser. I don't know if replacing it with a threaded end would improve things, I have 0 issues with tilt or the like.

Unfortunately, I only have this image atm, the red is approximately how deep the imaging train goes into the focuser:

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Jerry Gerber

Topic starter

Frequent contributor

Mar 19, 2024

Thanks Johannes!

I am thinking about getting this scope. Are you having any issues with the focuser being attached to the primary mirror?
I am absolutely determined to do indoor collimation, how are you collimating the scope? I am using the OCAL 3.0 collimator with the Edge and it works well.

Jerry

Johannes Maximilian Möslein

Mar 19, 2024

Hi,

I have zero issues with the telescope overall, which kinda surprised me after some reviews and explanations. I have no tilt, it holds collimation well and I like the image quality.

I collimated it in the night with a real star using the DSI-method: http://www.deepskyinstruments.com/truerc/docs/DSI_Collimation_Procedure_Ver_1.0.pdf
Honestly, I thought collimating was going to be worse, after all the horror stories I heard. But this method worked for me. It took two tries, but that was mainly because I never collimated a scope before, so the first night was a loss because of my lack of knowledge. If you know how collimation works, you should be fine.

I never tried a collimator, I recently got a Ronchi eyepiece to check the collimation, and even after almost a year, it was absolutely spot on.

Johannes

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Jerry Gerber

Topic starter

Frequent contributor

Mar 19, 2024

That's very encouraging to hear. I've been collimating an SCT with the OCAL 3.0 and it works very well. But I do not like the way stars usually look on an SCT and I don't like the focusing mechanism on the Edge.

I am allergic to standing out in the dark trying to collimate on a star that is always moving out of the FOV, it drives me nuts. I'd like to find a scope with a focal length around 1500mm that I love as much as I love imaging with refractors. I don't mind collimation at all but I insist on doing indoors! I found a refractor that fits the bill but it's just too long to use with a tripod, it needs a permanent pier, which I don't have and can't install.

Thanks Johannes!

Johannes Maximilian Möslein

Mar 19, 2024

If your collimator works like the one by TS, it should work: https://youtu.be/aLwTkyJZM1Y?si=5S6dNcr06VAi2bAX

Tim Ray

Mar 19, 2024

I have the RC10… focuser is attached to mirror. Replaced focuser with a Feathertouch 3" RP focuser with the 48mm threaded end cap…

No issues with focuser or collimation. I have an Ocal and a HowieG Laser collimator from Feathertouch. I only collimate indoors with the HG laser. I didn't have satisfactory results with the Ocal.

CS Tim

Jerry Gerber

Topic starter

Frequent contributor

Mar 19, 2024

Thanks Tim.

One company in Europe that sells the TS-Optics 8" RC writes that the advantage of RC over SCT is that the focuser and mirror are completely separate with the RC. I am not understanding what that means??

Jerry

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Brian Boyle

Mar 19, 2024 · Edited: Mar 19, 2024

Hi Jerry, I owned the RC8 and recently upgraded to an RC12.

With a FF sensor, I also needed a flattener, which simply screwed onto my ZWO imaging train of camera -> EFW -> OAG. And the whole image train just slid into the stock focusser, held be screws. No threads in mine.

You might also find that you need flattener with ZWO2600MC. The RC focal plane is curved, but Telescope Express sell a good 1.0x flattener.

The RC8 didn't have the optional collimation ring which allows you to align the focusser with the optical axis, but I didn'tneed it.

After being initially being spooked by the RC collimation horror stories, with the right gear [for me it was the Takahashi collimating scope], collimation was simpler and much most robust than a fast Newt. Collimation only needed to be checked monthly with the scope permanently mounted. And easily done during the day. Only hassle we to remove the 1ary baffle as I have big forearms.

The same is true of my new RC12 - actually I have found that even easily to collimate. It has an inbuilt collimation ring to adjust focuser tube wrt to the 1ary mirror, but I haven't needed to touch it. Collimating that scope to 30min on the dining room table. In over a months use, I have never needed to adjust collimation.

I also now have a Williams Optics focusser and reducer/corrector which help make the image train even more stable.

The RC design is great. Yes its has a smaller field than a Newt, but the stability and ease of use is hard to beat in my view.

I will be selling my RC8 with the flattener, and will be sorry to see it go.

CS Brian

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Jerry Gerber

Topic starter

Frequent contributor

Mar 19, 2024

Jerry Gerber:
Thanks Johannes!

I am thinking about getting this scope. Are you having any issues with the focuser being attached to the primary mirror?
I am absolutely determined to do indoor collimation, how are you collimating the scope? I am using the OCAL 3.0 collimator with the Edge and it works well.

Jerry

Johannes Maximilian Möslein:
Hi Jerry,

I have that scope. I just insert the front of my imaging train into the focuser and tighten the screws. If the first point of your imaging train is a thread, you probably need an adapter that you can insert into the focuser. I don't know if replacing it with a threaded end would improve things, I have 0 issues with tilt or the like.

Unfortunately, I only have this image atm, the red is approximately how deep the imaging train goes into the focuser:

I see you're using an OAG. Would a ZWO large OAG work with the RC 8 focuser?

Thanks,
Jerry

Brian Boyle

Mar 19, 2024

Hi Jerry, The OAG-L works just fine with the RC8.
CS Brian

Jerry Gerber

Topic starter

Frequent contributor

Mar 19, 2024

Brian Boyle:
Hi Jerry, The OAG-L works just fine with the RC8.
CS Brian

Hi Brian,

I am nearly ready to purchase the TS-Optics RC 8 carbon fiber scope. I have to purchase it from Germany as I cannot find any GSO scopes in stock in the US.
I hope I am getting everything all at once so I can dive in and learn this system. I'm getting the ZWO large OAG, the Astrozap dew shield, a Dew-Not dew heating strip for 8" scopes, and a TS-Optics M90 Tilting Adapter. I think TSO is pretty much the same scope as the GSO, I hope.

Might you know whether the scope ships with a dust cover on both ends of the scope?

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Brian Boyle

Mar 20, 2024

Jerry Gerber:
Brian Boyle:
Hi Jerry, The OAG-L works just fine with the RC8.
CS Brian

Hi Brian,

I am nearly ready to purchase the TS-Optics RC 8 carbon fiber scope. I have to purchase it from Germany as I cannot find any GSO scopes in stock in the US.
I hope I am getting everything all at once so I can dive in and learn this system. I'm getting the ZWO large OAG, the Astrozap dew shield, a Dew-Not dew heating strip for 8" scopes, and a TS-Optics M90 Tilting Adapter. I think TSO is pretty much the same scope as the GSO, I hope.

Might you know whether the scope ships with a dust cover on both ends of the scope?

Hi Jerry,

My GSO RC8 came with a dust cover on the "top end" and a 2" dust cap on the focuser end.

Brian