Here we have a first light of a new short focal length set-up I put together as part of a set of equipment I want to take to a new dark site from time to time.  This includes a Samyang 135, a Rainbow Astro RST-135, and the ASIAir Pro.  I also intend to use an 8" Newt with this as well but I thought working with the Samyang first might be a little easier.  

To set up the Samyang, I purchased an Astrodymium Ring System and fitted it with a ZWO EAF.

The Rainbow RST-135 is mounted on the pier system from the EQ8, the Starizona boys made me an adapter for this purpose.  Great guys over there...

So the initial impressions are pretty good!  I like the Astrodymium rings, the EAF works perfectly with the Samyang and I am blown away by the RST-135.  I had to fiddle with the guiding parameters quite a bit and fortunately there is a lot of material about this readily available on-line and I did manage to get it guiding over the several days of imaging at RMS numbers ranging from 0.48 arcsec to about 0.65 arcsec.  I did my NB work at 180 seconds without issue and I did play around with 300 second frames as well with no issue at all.

With the ASIAir, the meridian flips are perfect, plate solving is fast and spot-on accurate, and I really like the 2-step autofocusing routine.  On the other hand and for me anyway, I don't love the user interface of the ASIAir and as so many have reported, the WiFi is weak.  I did fit it with the recommended WiFi extender, the Vonets unit but abandoned that after one evening because the range was hardly better and it has a bunch of flashing lights on it that could not possibly be of any benefit to imaging.

The image itself ain't great, my focus was on getting all the equipment to sing together.  Moreover, I think I have a little spacing issue with the camera backfocus.  It plate solves at 128mm and the stars in the corners are not good.  But definitely sortable.  I shot this 1/2 stop from fully open to try to get better stars and flatness.  I think that would be at about f/2.4 as there is a detent in the ring between f/2 and f/2.8, and I was able to mostly avoid the diffraction spikes.  However, I do think I will try next time wide open and with the back-focus verified and see what happens.

And of course, I do need to shore up the cable management...

For the post-processing in Pixinsight, I employed  Frank Breslawski's "crazy formula" for the narrowband combination and then added the RGB stars.  Actually, Frank's method yields star colors very close to what I achieved using RGB.  Thank you @Frank Breslawski ,  I love that "crazy formula"1


Also a big thank you to @Nico Carver for a video on his fine YouTube channel that explained the surgical method necessary to modify the Samyang 135 so it can come to focus properly at infinity.  

We have a great community here with so many folks who generously share their knowledge.

Hope you like this one, clear skies and good health to everyone!