Pairing the asi2600mc duo with a Samyang 135mm lens - Forums

Hi

Anyone uses the asi2600mc duo with the samyang (Rokinon) 135mm lens?
I am thinking in buying the camera and use it with mag askar fra400 or ES102FCD but also would like to use it with my travel rig composed of a Samyang 135mm lens and would like to know if anyone has such configuration and if so any problems?

Thanks

Start with this: https://www.firstlightoptics.com/adapters/astro-essentials-samyang-lens-to-m48-adapter.html

You’ll also want this: https://www.firstlightoptics.com/zwo-accessories/zwo-2-filter-drawer-m42-m48-v2.html

This too: https://www.firstlightoptics.com/adapters/astro-essentials-m48-extension-tube-set-4mm-5mm-6mm-7mm-8mm-9mm.html

And finally, some of these: https://www.firstlightoptics.com/adapters/astro-essentials-m48-adjustment-spacer-ring-set.html

The backspacing for a canon ef version of the lens is 44mm. The asi2600mc is 17.5. The ZWO filter holder is 21. Thus you need an additional 5.5mm. However, when you add a filter in the holder, you need to increase the distance. With most filters you’ll need 6-6.5mm. You use the extension tubes and spacers to dial it in.

Hi Philip

I have may Samyang paired with the 533MC with ZWO filter holder and Nikon adapter and 533MM or 294MM with ZWO EFW and ZWO Nikon adapter. All this setups works great with pinpoint stars.
the million dollars question is the 2600MC DUO version. It has an M54 connection. So I need to know if anyone ever used and how

Thanks

I use the Samyang 135 with the ASI2600MM - or, I try to 😜
It’s a beast to calibrate in terms of tilt.
I bought an Octopi to fix that and even with that in place I still find it dufficult to get it perfect.
The images are great and removing the stars leave beautiful large scale structures behind.
For stars I think I will go to a slower F-ratio when I do those.
For now I’m stuck behind winter clouds in Denmark and have more or less not seen a star for 2 months.

The lens is awesome!

Philip has pointed you to all relevant parts that are needed, I do own the Nikon and the Canon version of the Sigma 135 and if possible you should take the Canon version because the m48 adapter makes things a lot more stable.

There is a thread with a lot of good info's in the Hardware forum for the samyang lens:

https://www.astrobin.com/forum/c/equipment-forums/samyang-135mm-f20-ed-umc/

I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

Bray Falls:
I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

What do you use for tilt adjustment with this setup, Bray?

Bray Falls:
I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

What do you use for tilt adjustment with this setup, Bray?

A piece of metal tape shimmed between the efw and the lens adapter!

Bruno Figueira:
Hi

Anyone uses the asi2600mc duo with the samyang (Rokinon) 135mm lens?
I am thinking in buying the camera and use it with mag askar fra400 or ES102FCD but also would like to use it with my travel rig composed of a Samyang 135mm lens and would like to know if anyone has such configuration and if so any problems?

Thanks

Bruno, did you end up getting the 135mm? And did the guiding work with the Duo? I have the Duo and am wondering, too, if there are any issues with guiding. Any info is appreciated!

Bray Falls:
I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

*** Bray, you mentioned there are no issues with guiding... are you using the 2600mc Duo for the guiding? I have the Duo and I am also concerned about the M48 thread and if it's wide enough for the Duo's guiding sensor. Any information is appreciated!

Michelle Roosette:
Bray Falls:
I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

*** Bray, you mentioned there are no issues with guiding... are you using the 2600mc Duo for the guiding? I have the Duo and I am also concerned about the M48 thread and if it's wide enough for the Duo's guiding sensor. Any information is appreciated!

Yes I use it for guiding, no issues with the lens adapter from zwo.

Bray Falls:
Michelle Roosette:
Bray Falls:
I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

*** Bray, you mentioned there are no issues with guiding... are you using the 2600mc Duo for the guiding? I have the Duo and I am also concerned about the M48 thread and if it's wide enough for the Duo's guiding sensor. Any information is appreciated!

Yes I use it for guiding, no issues with the lens adapter from zwo.

Thank you!

Bray Falls:
I use one with a 5 pos 2" EFW. Stars are perfect with the filters, both zwo lum filter and an L-extreme filter. I had to shim the threaded adapter for tip-tilt, but it only required a small adjustment. I use the lens at f/2.2

The autoguiding also works quite well in narrowband, especially since it is at f/2.

Hi Bray, did you notice any issues / loss in contrast with bandshifts at f/2.2?

I ordered the two Altair Duo Narrowband filters to image HaOIII and SIIOIII together at 6nm. Because of bad weather I couldn't test those yet, but I hope they will perform well also at lower f ratios.

Best,
David

Bruno Figueira:
Hi Philip

I have may Samyang paired with the 533MC with ZWO filter holder and Nikon adapter and 533MM or 294MM with ZWO EFW and ZWO Nikon adapter. All this setups works great with pinpoint stars.
the million dollars question is the 2600MC DUO version. It has an M54 connection. So I need to know if anyone ever used and how

Thanks

*** Bruno, did you ever get the answer to your $1M question? It seems most people think you are referring to the 2600mc (not necessarily the Duo.) I have the same question as to which adapter to use since the ZWO T2 adapter is M48 to M42, and the M42 seems too narrow for the DUO to be able to guide. Curious if you ever found a good solution. Any info is appreciated.

Hi Michelle

till now the only answer I have on this matter is an article by ZWO using this camera and a Canon 135mm. I used that information and bought a 2600MC Duo (still waiting for delivery).

https://astronomy-imaging-camera.com/news/am3-asi2600mc-duo-installation-guide-creating-an-ultra-portable-astrophotography-setup/

I think it will work but till I test it I dont really know (in ZWO website they advertise to pair tehhe camera with the T2 Nikon adapter sooo lets see

Bruno Figueira:
Hi @Michelle Rousset

till now the only answer I have on this matter is an article by ZWO using this camera and a Canon 135mm. I used that information and bought a 2600MC Duo (still waiting for delivery).

https://astronomy-imaging-camera.com/news/am3-asi2600mc-duo-installation-guide-creating-an-ultra-portable-astrophotography-setup/

I think it will work but till I test it I dont really know (in ZWO website they advertise to pair tehhe camera with the T2 Nikon adapter sooo lets see

Bruno Figueira:
Bruno Figueira:
Hi @Michelle Rousset

till now the only answer I have on this matter is an article by ZWO using this camera and a Canon 135mm. I used that information and bought a 2600MC Duo (still waiting for delivery).

https://astronomy-imaging-camera.com/news/am3-asi2600mc-duo-installation-guide-creating-an-ultra-portable-astrophotography-setup/

I think it will work but till I test it I dont really know (in ZWO website they advertise to pair tehhe camera with the T2 Nikon adapter sooo lets see

** Bruno, thank you so much for that link. In all my searches, I was unable to find that. It is indeed helpful. I have the T2 (Canon) adaptor already, but I haven't been able to test it - clouds. Attaching it to my 50mm canon lens, it seems too narrow, but I will see when the clouds clear if indeed it works. I plan on getting the 135mm soon. The Duo is an amazing camera and guider - you will love it. I use it with a svbony 122mm refractor and it works quite well. Please keep me updated on how it works for you!

@Michelle Rousset the 135 is a beast. I normally use it with the 533MM and MC and also with the 1600MM with good results.
Its rated as a full frame lens so I think no problem pairing with the 2600MC Duo. The problem is the Nikon adapter that is a T2 one but from that article it seems that it will work

Bruno Figueira:
@Michelle Rousset the 135 is a beast. I normally use it with the 533MM and MC and also with the 1600MM with good results.
Its rated as a full frame lens so I think no problem pairing with the 2600MC Duo. The problem is the Nikon adapter that is a T2 one but from that article it seems that it will work

**Bruno, exactly! It's the limiting M42 diameter of the adapter that I'm concerned with! Time will tell when we start testing. Thanks again for your input!

I’m about to pair my Samyang 135mm with the Duo, just waiting on the EOS T2 adapter to arrive. I’ll update everyone once it’s here.

During the summer, I had a blast using my Samyang 135mm lens. I paired it with the 533MCP without any tilt issues at f/2.

Andy:
I’m about to pair my Samyang 135mm with the Duo, just waiting on the EOS T2 adapter to arrive. I’ll update everyone once it’s here.

During the summer, I had a blast using my Samyang 135mm lens. I paired it with the 533MCP without any tilt issues at f/2.

*** Thanks, Andy! I was playing around with the various combinations (I have the EOS T2 adapter and Duo, but waiting to pull the trigger on the 135mm) and noticed that the adapter has 3 components. The actual component with the bayonet has M54 thread. I'm wondering if there is an 15mm extender with M54 thread to reach 44mm back focus. It would be adapter (~11.5mm) + extender (15mm) + Duo (17.5mm) = 44mm. This way, it would have a wide open access of 54mm all the way through to the camera sensor with the correct back focus.

Thoughts?

Hi @Michelle Rousset the ZWO Nikon and I suppose Canon also adapter only needs the 11mm that cames with the camera to reach focus (Adapter, 11mm and camera). I'm guessing you're using the one with the filter drawer. And by the way its not 44mm but 55mm.
44mm is only when using DSLR

Bruno Figueira:
Hi @Michelle Rousset the ZWO Nikon and I suppose Canon also adapter only needs the 11mm that cames with the camera to reach focus (Adapter, 11mm and camera). I'm guessing you're using the one with the filter drawer. And by the way its not 44mm but 55mm.
44mm is only when using DSLR

*** Bruno, I have just the Canon adapter - not the one with the filter drawer.

As for the back focus, I've never heard that about 44mm with the DSLR. There wouldn't seem to be a need to discuss the backfocus if using a DSLR because it's already built in by the camera/lens manufacturers? From everything I've read, it is 44mm with dedicated cameras as noted in this diagram from ZWO regarding the Duo, where (1) is the Nikon T2 adapter (2) is the Canon T2 adapter. Apparently they seem to be quite liberal with the 44mm backfocus as neither of these are actually 44mm. I've seen some discrepancies in their documentation, so... take it all with a grain of salt.

I'm curious... where did you read that the backfocus is 55mm when using a camera lens? I'm happy to be wrong, I just want to get the right info in my brain!

@Michelle Rousset you're absolutly right. my mistake. Just use as the figure and it will work nicelly. As you can see in my last photo last night

NGC2244.jpg