Imaging with the Samyang 135mm f2

[geordie85]

Here's a very quick M45 as a test image.

24 x 60 second Luminance, 11 x 30 second RGB taken from my back garden with bortle 6 skies at f2.8

[david_taurus83]

On 05/12/2020 at 20:46, nephilim said:

Its arrived & it's a lovely piece of glass 

 

Snap!

I'm looking to mount this on top of my scope with my 6D and snap wide field shots while gathering narrowband with my Atik. Best of both worlds!

[nephilim]

29 minutes ago, david_taurus83 said:

Snap!

I'm looking to mount this on top of my scope with my 6D and snap wide field shots while gathering narrowband with my Atik. Best of both worlds!

Nice.

[david_taurus83]

Got this cheap tripod collar today. Surprised there isn't a proper one made for this lens. Anyway, this one is 71mm so slightly too big but nothing a few wraps of tape around the lens can't fix! A bit of careful cutting away of excess tape also leaves the aperture ring free to rotate unlike the Redcat collar. I'm planning to fix a mini dovetail bar to the foot of this so I can mount it into the William Optics slide handle on my scope.

These are on Amazon for anyone interested.

https://www.amazon.co.uk/dp/B07DVKZBXG/ref=cm_sw_r_cp_apa_fabc_NAa0FbMCARMM2?_encoding=UTF8&psc=1

 

 

[ultranova]

Nice catch on these, i see you have what looks like a piece of thin plastic

to take up the 1mm slack on the diameter of the lens, good idea

I have just purchased two of the rings and some self adhesive felt off Amazon.

Thanks for sharing the info 

Paul

[david_taurus83]

1 hour ago, ultranova said:

Nice catch on these, i see you have what looks like a piece of thin plastic

to take up the 1mm slack on the diameter of the lens, good idea

I have just purchased two of the rings and some self adhesive felt off Amazon.

Thanks for sharing the info 

Paul

I just used some blue electricians tape and added a few layers until I was happy that it was a good fit. Used a razor blade to trim the edge off to free up the aperture ring. Just waiting on my mini dovetail now so can mount it to the scope handle.

[Space Oddities]

57 minutes ago, david_taurus83 said:

I just used some blue electricians tape and added a few layers until I was happy that it was a good fit. Used a razor blade to trim the edge off to free up the aperture ring. Just waiting on my mini dovetail now so can mount it to the scope handle.

I tried that as well a couple years ago, but ran into problems when I tried to rotate the lens. Some parts of the tape was sticky where it shouldn't be, and created a huge mess... it was dark and didn't see what was happening until it was too late  

I like the idea of the ring though, it should make rotating the lens much easier! Well done!+

Speaking of adhesive: I tuned the 360° rotator I recently added, and added a scale, to help me with flats   Still waiting for a very lightweight guide scope I ordered from Aliexpress, that should make the rig even more portable and travel friendly, and I guess the setup will be complete!

 

[david_taurus83]

The final parts came today. An Optolong L Pro clip in for my 6D and a mini dovetail. Its a perfect fit for the William Optics scope handles.

I drilled and tapped a couple of M6 holes in the foot of the collar.

 

 

For added security a put an extra thumbscrew into the handle so there's no mishaps with it sliding out of there as its fairly heavy.

 

Ready!

 

I added a few thin strips of foam to the B mask I was using for the Altair 80EDR so hoping I can use this for focusing the lens.

 

 

Its a guaranteed cloud free night tonight folks!! No problems here! Who's with me? Maybe some mass positive vibes will keep cloud at bay for an evening!

 

[david_taurus83]

Altair 80mm bahtinov mask works a treat.

Currently running Oiii on the Atik/Altair 80 combo and wide field of the same target with the Samy/6D at f3.5.

Also running 2 instances of NINA for image capture.

 

[Space Oddities]

Looking great David!  

I'd love to join, but only clouds here in Bavaria... and the current curfew from 9pm doesn't help either! 

I think my next purchase will be a garden with a view... Hopefully FLO will start selling these!

[geeklee]

Yep, very jealous David! Still waiting for first light with the 135. I'm hoping later this week but with the current weather, who knows. Good luck for a full clear night tonight. 

[nephilim]

Hope you get a good clear run, nothing but clouds & clag here in the Lakes as usual.

[david_taurus83]

I think I've got maybe another hour here before a bank of cloud moves in from the west by the looks on Sat24. At least its nice to be doing something. Also trying out the new multi star guiding on PHD. Its currently chugging away at 0.30RMS on my little CEM25!

 

[Adreneline]

My first RGB image with the 135mm. Not the best target to image and my RGB processing needs some work - it's been an age since I last processed an RGB image. The Bortle 3/4 skies certainly help compared with Bortle 5/6 at our previous location.

This is 20x60s of R, G and B. Integrated in APP, pre-processed in PixInsight and tweaked in Affinity.

Some star distortion which is most apparent in the top corners; any thoughts as to what might be causing this?

Adrian

Edited December 13, 2020 by Adreneline

[Space Oddities]

I'm starting to wonder if this isn't a problem with all copies of the 135mm. One corner always seems to have weird stars! Perhaps a misalignment of one of the many lenses inside?

Great picture nonetheless, Adrian! I love that tiny galaxy you also captured in the bottom left corner!

[Adreneline]

1 hour ago, Space Oddities said:

One corner always seems to have weird stars!

At least there is some scope to crop it out!

Thank you! Glad you like the image - hadn't spotted the galaxy - it's nearly a challenge to spot the Iris!

Adrian

[Space Oddities]

Are you using the Canon version, or did you mode it with Rob's fantastic 48mm adapter? I haven't had a chance to test mine that just arrived, but I remember my Canon to T2 adapter wasn't particularly tight, and I suspect it also created a very slight tilt. I hope this M48 adapter will help in that regard!

Otherwise, I see no other option, except using a tilt adapter in between...

[Adreneline]

19 minutes ago, Space Oddities said:

Are you using the Canon version, or did you mode it with Rob's fantastic 48mm adapter?

I'm using the Astrojolo version - same thing really. I suppose it could be a sensor tilt issue - wouldn't take much. I don't think I want to go down the road of a tilt adapter - too complicated. I'm trying to keep my setup simple.

DynamicCrop will sort it that's for sure  

Thanks.

Adrian

[Space Oddities]

I also believe that's too much complexity, for a setup that's supposed to be simple. Also, I use mine with small sensors (ASI1600 or ASI178) anyway, so I don't think it's worth it.

Also, it could be worse! Check out that horrible tilt, you can see it pretty clearly with even a compressed image... I understand why Samyang is infamous for their QC...

I also read this user saying he uses a step down filter to improve the star shape in the corners. Kind of defeat the purpose of an f/2 lens, but with his technique of star removal, he gets the best of both worlds. I just drop that here, in case anyone is interested  

[david_taurus83]

My first night out was plagued by clouds. Second night out i had a wandering dust bunny that changed position every frame rendering flats useless. Finally tonight the clouds stayed away for a couple of hours and the dust bunnies stayed in on place for the most part. I was imaging NGC896 in Oiii on the main scope so just set the Samy/6D snapping away on top, hence the off centre framing. Lens stopped down to f4 and it gives good results to the edge, even on the full frame 6D. Wish I had bought this lens earlier instead of experimenting with Canon lenses!

23 x 300s f4 @ ISO1600. Quick bash in PI and PS.

 

[Ande]

Recently bought one of these lenses, and am slowly getting everything together for imaging.  Next on my list is a Bhatinov mask. Is there one made specifically for this lens that is worthy of recommendation? I’ve seen a few 3D-printed ones on eBay, but not sure if they’re any good.

[nicoscy]

You can get someone to 3D print this for you

[geordie85]

49 minutes ago, Ande said:

Recently bought one of these lenses, and am slowly getting everything together for imaging.  Next on my list is a Bhatinov mask. Is there one made specifically for this lens that is worthy of recommendation? I’ve seen a few 3D-printed ones on eBay, but not sure if they’re any good.

I just use the one that's for a wo star 71. 

[Ande]

58 minutes ago, nicoscy said:

You can get someone to 3D print this for you

Thanks @nicoscy  That looks excellent. Unfortunately, I don’t have a 3D printer, nor do I know anyone that has. That’s something I would like to rectify in the future though :

[Ande]

Cheers @geordie85.  I’ll put that down as a possibility