Imaging with the Samyang 135mm f2

[Simon Pepper]

2 minutes ago, Elp said:

What adaptors have you got currently? The above just make it easier to mount as you don't need to mess around with backspacing much with or without filters. I setup and breakdown every time and have never had issues other than the typical tilt.

 

I have the usual 16.5mm and 21mm spacers and I have swapped out the back of the lens canon fit with a threaded adapter below but it’s the same size as the samyang one so makes no difference to length.

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

 

thanks 

[Elp]

You need something like this:

https://www.firstlightoptics.com/adapters/astro-essentials-t2-m42-extension-tube-set-4mm-5mm-6mm-7mm-8mm-9mm.html

There's also another version with 5mm increment rings.

And you also need an m42 male to m48 female adaptor ring to couple the spacers to the back of the lens adaptor.

These things are always useful to have lying around if you use refractors a lot with different reducers.

Edited January 28 by Elp

[aleixandrus]

I also suggest purchase some 0.1-0.2mm spacers for fine tuning. My ASI183MM plus the Samyang focuses a little bit away than suggested 44mm+1/3 filter. Adding that small spacers makes a huge difference in focus position at f2-f2.8 . I also suggests to 'surgery' the Samyang to move the infinity hard stop to have some extra room past infinity, specially in the case you are adding auto focus. Is a quite straightforward operation and it worth it.

Oh, I also have that adapter to replace the Canon EF mount. I measure the backfocus distance from the front face of the adapter one put in place (not the screw, not the back face).

Edited January 30 by aleixandrus

[Simon Pepper]

Thanks here is what I have so far. Waiting for a 5mm spacer to hopefully turn up from FLO today. Point noted on the hard stop. Just out of interest and I was going to start a new thread but on the subject of tilt and getting it dialled in how does one actually go about mitigating it? How can you tell from an image where the adjustments need to be made? Surely it’s a nightmare understanding that after unscrewing and screwing back the camera? Thanks 

[aleixandrus]

I've considered adding a tilter but the good ones (with easy access to adjust) are expensive and after many many struggles with backfocus, I get reasonable stars without adjusting tilt (specially as my ASI183MM has a very small sensor). I have finally decided to live just this way, specially after discovering BlurXTerminator. Maybe in the future I would get a camera with integrated tilter as those PlayerOne. But please, check my previous post where I added more info. I have a very similar setup, so I think you could find it useful.

[Simon Pepper]

29 minutes ago, aleixandrus said:

I've considered adding a tilter but the good ones (with easy access to adjust) are expensive and after many many struggles with backfocus, I get reasonable stars without adjusting tilt (specially as my ASI183MM has a very small sensor). I have finally decided to live just this way, specially after discovering BlurXTerminator. Maybe in the future I would get a camera with integrated tilter as those PlayerOne. But please, check my previous post where I added more info. I have a very similar setup, so I think you could find it useful.

Very interesting and I had actually read this one before. So far not even tested the Sammy yet so those first shots will be interesting I have it paired with 2600mc so tilt could be very evident but at least no filters to deal with. I’ll start at 44mm and go from there. Was your testing always at f2.8 do you laws leave the aperture there? Thanks 

[Elp]

I usually use 183s, largest is a 294. Because I setup and break down every time I don't bother with the tilt, just crop it out or leave it in. The target is more important than periphery star shapes for me. Larger sensor, more of a problem.

[Petrol]

Hope people are getting better skies than me! Managed about 8 hours on the Iris neb with a Player One OSC Cam.
 

 

 

 
 

 

All comments welcome.

Pete

[Petrol]

Markarian's Chain region. Not sure what the problem is on the top right and lower left. Thought it would be interesting to see how many galaxies I could get

 

 

Pete