It’s been nearly two years since acquiring my Samyang 135 lens but since then it’s unfortunately only had limited use in combination with my modded 550D DSLR.  Whilst impressed with the results from this set-up, my main objective has always been to combine it with my ASI1600 mono camera for some serious widefield astrophotography but as that was being used with my William Optics refractor it just didn’t happen, until now.  After upgrading to a ASI294MM Pro camera in May, at last I was finally able spend the early part of this summer working on a new Samyang 135 + ASI1600 rig and now that astronomical darkness is (just) back I recently managed to catch a few photons with this new set-up of the large SNR Cygnus Loop.

I originally purchased a x2-ring Astrokraken 3D-printed clamping system for the lens + DSLR combination from Philippe in France but since then he’s tweaked the design.  In particular x3 built-in M4 nuts have been incorporated on either side of each of the two main lens clamping rings, for the purpose of attaching ancillary equipment, which for me has been a game changer.  I therefore bought a new x3-ring Astrokraken bracket, with the said bolt holes, around which to build my new rig: 

• The two main clamping rings that hold the lens have a shoe immediately above the lens, to which I’ve fitted a Sky-Watcher EvoGuide 50ED guidescope (not yet working), with the rear third ring holding the ASI1600 mono camera & EFW. 
• I swapped the Canon lens bayonet adapter for a bespoke M42 screw adapter, in order to ensure a more secure attachment, thus reducing any potential lens-camera movement at this critical point of the image train.  
• I’m continuing to use the excellent Astrokraken micro-focuser, which consists of a ring that clamps onto to the lens’ focus ring, with two small bolts above that make contact with either side of the guidescope shoe, so that when turned the focus ring can be adjusted either way to obtain focus, which is then locked when completed.  So far I’ve found the micro-focuser to work very well with this lens, assisted by the addition of an Astrokraken Bahtinov mask which is inserted into the front of the lens casing.  
• Using this lens with the ZWO ASI1600MM-Cool camera and EFW, the backfocus guideline is 44mm, which I was able to achieve by adding an Altair T2 variable locking extension ring set to 17.5mm = 44mm minus 26.5 (camera + EFW).  
• With my Chroma filters now being used with the new ASI294MM Pro camera, I purchased another ZWO 31mm x8 EFW and brought my ZWO 31mm filters out of retirement. 
• Finally, using the new M4 nut holes I’ve added a Baader Skysurfer III RDF on the left-hand side of the Astrokraken bracket system to help with sky navigation and framing. 

After bolting the Astrokraken with the lens, camera and said components to a Losmandy plate it makes a very nice compact rig, that is easy to handle and store.  Notwithstanding, as they say – the proof of the pudding is in the eating: SEE top-of-the page for original image & below for 50% crop.  

Whilst the recent heatwave produced clear skies, it was far from ideal here for astronomy and was further hampered by a full moon.  However, with only just over two hours integration time and a few Dark calibration files, I’m still impressed with the outcome of this quite amazing lens.  It is very pleasing to capture the entire Cygnus Loop comfortably sitting within the lens’ FOV – for information on this FOV and comparisons go to this previous WTSM blog HERE.  For me context is important with astrophotography and in this regard the astronomical perspective this lens produces is outstanding, no wonder it is so popular.  I just love working with this FOV and can’t wait for better conditions for greater integration time and more widefield targets to point this wicked little lens at.