Observatório Astrográfico do Boqueirão:
Hello Jandro, the most thinner rotator that comes up to mind is the TS-Optics 360 Rotator Quick Change, but in my personal opinion since I tried to use one, you need a tilter with him, otherwise you'll have tilt that you can't solve. He have a thickness of 5.5mm, but the way that he's build, at so wide open aperture, you can see the problem that he causes since the adjustments to lock him in place are made by two screws.
The solution passes by using it combined with a tilter to compensate the other side of the locking screws. I tried at first, but at some point I put him aside, and everytime I need to do a field rotation, I rotate the entire lens system in the clamp rings.
This is one of the reasons that I'm still a huge fan of the old system cameras of ZWO and Altair, and thats why I still didn't move from the 1600MM and 294MC/MM. Same goes for the 533 Pro and 585 Pro.
That design of cameras, allows to go from a backfocus of 6.5mm up to 17.5mm and the possibility of using a inner adapter from those M42 to 1.25" to use filters close to the sensor and inside the female T2 11mm adapter ring of ZWO, allows a bunch of combination on such narrow systems. I have my system right now with a filter drawer and a tilter, but I'm considering in the future to change the system by removing the filter drawer and put a CAA, and the filters goes for 1.25" inside the optical train close by the sensor. This way I can have the filter, the tilter and a rotator all in one system. Everytime I need to change filters, I just unscrew the camera, because in the case of the mono cameras, I only shoot one filter per night or for several nights until I find the desired SNR to Hours that I want.
In my personal opinion, EFW only makes sense if you use them in remote observatories that you don't have access. Shooting more than one filter in a single night, it's not practical.
But this is just me.
Hope this helps to clarify or rethink your system.
Regards,
Cesar
Noah Tingey:
I've seen some people remove the bayonet from the rear of the samyang and squeeze out a bit more backfocus distance from that. Not sure how that's done, though. But maybe worth looking into.
andrea tasselli:adaptor to m48-m42
Zero thickness:
ZWO M48 to M42 Adapter Ring | First Light Optics
andrea tasselli:adaptor to m48-m42
Zero thickness:
ZWO M48 to M42 Adapter Ring | First Light Optics
andrea tasselli:
Then you can take a m42/m48 female flange and drill the 3 holes and have a direct connection to the rotator. Is the rotator flange male or female?
andrea tasselli:
So, male M42 flange to be drilled to fit on the Rokinon and that saves 5mm.
andrea tasselli:
Apologies as I haven't made it clear enough. What I am proposing is to replace the FLO M48 adapter with a "modified" M56 to M42 male one (I think it should do but I can check with my copy of the lens). The modification will consists in:
1. Machine away the M56 thread, leaving just the flange and the M42 male thread
2. Drill 3 holes of the right diameter and at the correct distance from the center to mount the newly modded M42 male adaptor to the lens in place of the FLO one
I could easily do it in my garage with modest tools (basic milling machine and lathe).
I spent some time on that topic. There's no adapter on the market that I know of, that can go from M48F to M42M that is less than 11.5mm thick. Apart from the TS 5.5mm one + M48-M42 adapter, but as you said, it's probably not meant to handle a heavy camera and FW.*
It's a pity that the EFW has T2 threads. My 36mm EFW from Ogma has M54 threads, which would have been convenient in your case. M48-M48 slim rotator + a M48-M54 ring. You'd have enough space for these.
What about rotating the lens & camera as a whole? What kind of mounting system do you have? Would it allow rotation? It's not as convenient, but if you're doing one target per night, that might not be too cumbersome.
Thinking out of the box here: what about repurposing an OAG as a rotation unit?
TS makes a very thin one, I believe it's 9mm thick. It has M48 female threads on the telescope side, and T2 threads on the camera side (with the right adapter):
OAG: Teleskop-Express: TS-Optics Off-Axis Guider TSOAG9 - Length only 9 mm-TSOAG9G2
T2 adapter: Teleskop-Express: T2 Ring for TS Off-Axis Guider TSOAG9 and TSOAG16-TSOAG9-T2
If you remove the prism unit and tape the hole, that could work. The only issue I see, is that the adapter has 3 gaps. But that might be sufficient for you.
I spent some time on that topic. There's no adapter on the market that I know of, that can go from M48F to M42M that is less than 11.5mm thick. Apart from the TS 5.5mm one + M48-M42 adapter, but as you said, it's probably not meant to handle a heavy camera and FW.*
It's a pity that the EFW has T2 threads. My 36mm EFW from Ogma has M54 threads, which would have been convenient in your case. M48-M48 slim rotator + a M48-M54 ring. You'd have enough space for these.
What about rotating the lens & camera as a whole? What kind of mounting system do you have? Would it allow rotation? It's not as convenient, but if you're doing one target per night, that might not be too cumbersome.
The problem is that to rotate the camera and frame the target, I have to remove the strap that goes to the eaf and then I lose focus, refocus to reframe the target, so on. And I mounted the eaf because this lens at f2.0 loses focus with a small temperature difference. It's not the first time I've thrown a night sesion away for that reason. I now have autofocus which is great but rotation is now a pain.
Thinking out of the box here: what about repurposing an OAG as a rotation unit?
TS makes a very thin one, I believe it's 9mm thick. It has M48 female threads on the telescope side, and T2 threads on the camera side (with the right adapter):
OAG: Teleskop-Express: TS-Optics Off-Axis Guider TSOAG9 - Length only 9 mm-TSOAG9G2
T2 adapter: Teleskop-Express: T2 Ring for TS Off-Axis Guider TSOAG9 and TSOAG16-TSOAG9-T2
If you remove the prism unit and tape the hole, that could work. The only issue I see, is that the adapter has 3 gaps. But that might be sufficient for you.
Maybe oag is a great solution, indeed i can remove my guide scope too.
I spent some time on that topic. There's no adapter on the market that I know of, that can go from M48F to M42M that is less than 11.5mm thick. Apart from the TS 5.5mm one + M48-M42 adapter, but as you said, it's probably not meant to handle a heavy camera and FW.*
It's a pity that the EFW has T2 threads. My 36mm EFW from Ogma has M54 threads, which would have been convenient in your case. M48-M48 slim rotator + a M48-M54 ring. You'd have enough space for these.
What about rotating the lens & camera as a whole? What kind of mounting system do you have? Would it allow rotation? It's not as convenient, but if you're doing one target per night, that might not be too cumbersome.
The problem is that to rotate the camera and frame the target, I have to remove the strap that goes to the eaf and then I lose focus, refocus to reframe the target, so on. And I mounted the eaf because this lens at f2.0 loses focus with a small temperature difference. It's not the first time I've thrown a night sesion away for that reason. I now have autofocus which is great but rotation is now a pain.
Oh, I haven't thought about the EAF's belt, indeed. I have the same issue actually!Thinking out of the box here: what about repurposing an OAG as a rotation unit?
TS makes a very thin one, I believe it's 9mm thick. It has M48 female threads on the telescope side, and T2 threads on the camera side (with the right adapter):
OAG: Teleskop-Express: TS-Optics Off-Axis Guider TSOAG9 - Length only 9 mm-TSOAG9G2
T2 adapter: Teleskop-Express: T2 Ring for TS Off-Axis Guider TSOAG9 and TSOAG16-TSOAG9-T2
If you remove the prism unit and tape the hole, that could work. The only issue I see, is that the adapter has 3 gaps. But that might be sufficient for you.
Maybe oag is a great solution, indeed i can remove my guide scope too.
Some people managed to make it work with an APS-C camera, it seems: AZ-GTI wit Samyang 135 and OAG - Photo Gallery - Cloudy Nights
OAG is always a bit risky, but that might work.
Also, you might need to add some spacer rings between the OAG and the EFW. Unless you're very lucky, the threads will probably not align in a way where the OAG is "on top", like this:
c44d136bb3a71e853353ea44bc71fc74-img.jpg (320×240)
So you might lose a bit of that precious flange distance
But then again, you always have the plan B to use the OAG as a rotator, in which case, the alignment doesn't matter
