Imaging with the Samyang 135mm f2

[kirkster501]

Made some major mods to my rig too.  Doesn't get dark until too late to test at the moment though.

[Craney]

A few images from Yorkshire skies over the last few clear nights.  ( Samyang 135  with Atik414mono  ).

First  two  are Hubble palette with about 30mins total time on each wavelength.

NAN and Pelican Mosaic

Nelly's Trunk

Now this is the one.....long term project time !!!!.... The Flying Bat  Nebula   (no, I have not made that up)..... with a hint of the Squid Nebula contained within.

Maybe it's just my imagination, or the pattern created by those central stars, but there's a hint of a Decapod.......

This is in Ha-O3 (  40mins Ha and 80mins O3).   I will probably need to get those integration times up into the 'hours' to reveal the demon of the deep !!!

All the best, Sean.

 

[carastro]

Done some more images with this excellent lens, but I do have a problem.  I was sure I was getting focus OK when I first started, but seems I can only get focus with Lum and Ha, but Oiii, Sii and RGB are just slightly out i.e. the Bahtinov crosshair is just slightly off centre.  I can't focus any further as I am at the limit of the focusser ring.  

With some nifty processing I am managing to produce a result as these are the colour elements which I can blur and place the ha or Lum over the top.  But I really would like to be able to sort this out but am rubbish with statistics and spacing etc. 

Do I need more space or less space is the question?  I am using Baader filters and Atik Camera and EFW and Modern Astronomy Canon lens to ZWO adapter which seems to fit OK, but I can't get any closer.

I have a sneaking suspicion I need to get closer which is impossible, so I contacted FLO to see if Rob's adapter would fit my EFW, but apparently I would need an adapter to make that fit and I would be back to square 1.   Absolutely no way I can get anywhere near the L as Adrenaline says. 

I haven't even mentioned the night when I pulled my scope cover off the rig which had been protecting my kit while I had a friend in (socially distanced) to repair my delapidating POD Zenith table.  The scope cover when I went to take it off the following night, pulled the EFW anticlockwise which then (with the weight) spun a further 90 degrees and the whole EFW and Atik camera became disconnected from the Samyang lens and crashed onto the floor of my Observatory.  Heart sank!!!!  Luckily it appears not to have caused any damage - hopefully having foam interlocked matting on the floor and decking under that might have saved the day. 

Anyway without more ado, this is the result of my latest efforts:  

Taken over 2 nights May 2020 from Bortle 8
Samyang 135mm F2 lens stopped down to F2.8
Atik460EX and Baader filters
HEQ5
Ha 2 x 600secs + 6 x 900secs
Oiii 6 x 300secs binned + 3 x 600 unbinned
RGB 3 x 150 (each)
Total imaging time 2hours 55mins (almost 3 hours)

This is taken over 4 nights, but some nights I didn't collect much due to cloud, short night and Clamshell dome obstruction.

I decided not to waste any more time trying to reveal the Squid in Bortle 8, though I did do twice as much data on Oiii as the Ha with a fast lens.

In total:
Ha 12 x 600secs (total 2 hours)
Oiii 2 x 20mins, 2 x 30mins, and 7 x 15mins 3 x 900secs binned x 2 (total 4 hours 10 mins)

Atik460EX and Samyang 135mm F2 lens @ F2.8
Guided on HEQ5

Total imaging time 6 hours and 10 mins.

 

Taken over 2 short nights during nautical twilight in SE London.
SHO palette with added RGB stars

Atik 460EX, Samyang 135mm F2 lens @ F2.8
Guided on HEQ5
Ha 15 x 600secs (2 1/2 hours)
Oiii 7 x 600 secs (1 hour 10 mins)
Sii 8 x 600secs (1 hour 20mins)
RGB 3 x 150secs Each 22.5 mins

Total 5 hours 22.5 mins

WOW, just noticed I got a TOP PICK for this on Astrobin, only my second TOP PICK ever and there I was wondering whether it was too garish.  

 

I then combined the Crescent image with my previous image of the Sadr region and made a mosaic.

(am still filling in the corners).

Edited June 28, 2020 by carastro

[Adreneline]

1 hour ago, carastro said:

Do I need more space or less space is the question?

Hi Carole,

It's not easy to answer your question, however, let's say I set up a camera with a lens and set the focus position on the lens to a little before the 'L' and adjust the spacing so that the image is in focus. If I then move the focus ring on the lens to the mid point of the 'L' I have to move the sensor away from the lens, i.e. increase the spacing, to achieve focus. This would seem to imply you need to decrease the spacing a little, probably by something as little as 0.2 mm or maybe less.

Just for your information these are the focus positions for my setup of Baader filters. The numbers represent the focus position of the ZWO-EAF:

If I were to set the focus at the Median position the end result for narrowband would be disappointing. The filters might be supposedly parafocal but I'm not sure the lens treats all wavelengths equally!

I hope this helps.

Adrian

[MarkAR]

Lovely images Carole.

As for the spacing, I would try adding a thin spacer and if it's worse then you'll know you need to shorten things up.

It might be possible to machine down the thickness of a part or two to achieve this.

Another option is that the focuser on the lens might be able to be adjusted for more travel, I think some of the Samyangs can be tweaked.

Edited June 28, 2020 by MarkAR

[MarkAR]

This might help.

https://www.youtube.com/watch?time_continue=7&v=gtt9bcJDU2U&feature=emb_logo

 

[Laurin Dave]

All very nice Carole and congratulations  on your "Top Pick"   ...  Here's another Veil..  5 minutes each RGB and 150 minutes each Ha and Oiii, ASI1600, major crop to remove dodgy stars caused by tilt  and spacing, sorting that out will be a task for when it gets dark at a slightly more sociable hour.  

Dave

[TareqPhoto]

As long i like the lens results but i have the Canon version only and also i have a second camera i am thinking about getting this lens to use 2 cameras, but i really feel that as much i like wide field but i don't like this super wide field always, i mean some targets can be nice like Cygnus targets, but another targets i feel like i really want to stay within 300-600mm range, and i don't know if i should really buy another 135mm lens.

[Craney]

20 minutes ago, TareqPhoto said:

As long i like the lens results but i have the Canon version only and also i have a second camera i am thinking about getting this lens to use 2 cameras....

You can unscrew the Canon bayonet fitting at the camera end of the lens and add a new plate that will couple the lens with pretty much any CCD/CMOS you like.   I use my cooled Atik 414ex and in a sense raise the effective focal length by reducing the chip size as compared to a DSLR.

Just calculate the correct back-focus and have a play with various connectors and extensions.

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

[TareqPhoto]

On 28/06/2020 at 17:48, Craney said:

You can unscrew the Canon bayonet fitting at the camera end of the lens and add a new plate that will couple the lens with pretty much any CCD/CMOS you like.   I use my cooled Atik 414ex and in a sense raise the effective focal length by reducing the chip size as compared to a DSLR.

Just calculate the correct back-focus and have a play with various connectors and extensions.

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

I don't understand your comment, but id you mean about to connect the Canon lens to my astro camera CMOS then i have many adapters for Canon T-mount, so i wasn't asking about how to connect the lens, i was asking about getting another 135mm lens let it be Samyang for example so i can go dual 135mm.

[Craney]

1 minute ago, TareqPhoto said:

.... i wasn't asking about how to connect the lens, i was asking about getting another 135mm lens let it be Samyang for example so i can go dual 135mm.

Sorry, my mistake. 

[TareqPhoto]

34 minutes ago, Craney said:

Sorry, my mistake. 

No problem

[david_taurus83]

On 28/06/2020 at 14:23, TareqPhoto said:

As long i like the lens results but i have the Canon version only and also i have a second camera i am thinking about getting this lens to use 2 cameras, but i really feel that as much i like wide field but i don't like this super wide field always, i mean some targets can be nice like Cygnus targets, but another targets i feel like i really want to stay within 300-600mm range, and i don't know if i should really buy another 135mm lens.

Is it the Canon EF 135mm F2 you already have? How do you find it? I've just bought one.

[TareqPhoto]

2 minutes ago, david_taurus83 said:

Is it the Canon EF 135mm F2 you already have? How do you find it? I've just bought one.

Yes, it is the Canon one, i bought it very long time in the past when i was in photography, and for that it is a remarkable sharp amazing lens, but now coming to astrophotography i can't tell much as i didn't test it much, only once and didn't process the image since 3-4 months ago, but i see more people favor Samyang or Rokinon, they said that Canon has issues wide open more than Samyang/Rokinon versions, but stopping down to F4 or more then there is no much difference.

[david_taurus83]

14 minutes ago, TareqPhoto said:

Yes, it is the Canon one, i bought it very long time in the past when i was in photography, and for that it is a remarkable sharp amazing lens, but now coming to astrophotography i can't tell much as i didn't test it much, only once and didn't process the image since 3-4 months ago, but i see more people favor Samyang or Rokinon, they said that Canon has issues wide open more than Samyang/Rokinon versions, but stopping down to F4 or more then there is no much difference.

Interesting, thanks. I've seen some nice pics on Astrobin with the canon version, even a full frame 6D image with nice round stars to the corners. I picked up a mint example for a little more than a new Samyang. I'm trusting the Canon build quality over the Samyang I suppose and there is the bonus of autofocus and the ability to control focus from APT should the need arise.

[TareqPhoto]

2 hours ago, david_taurus83 said:

Interesting, thanks. I've seen some nice pics on Astrobin with the canon version, even a full frame 6D image with nice round stars to the corners. I picked up a mint example for a little more than a new Samyang. I'm trusting the Canon build quality over the Samyang I suppose and there is the bonus of autofocus and the ability to control focus from APT should the need arise.

AS body or quality design the Canon is superior, but Samyang did great for CA and wide open, so that Samyang for example is nicer result wide open, but once you close down then Canon will hold its value and quality, and in photography then autofocuser and build design is big bonus.

[carastro]

Quote

You can unscrew the Canon bayonet fitting at the camera end of the lens and add a new plate that will couple the lens with pretty much any CCD/CMOS you like.   I use my cooled Atik 414ex and in a sense raise the effective focal length by reducing the chip size as compared to a DSLR.

Just calculate the correct back-focus and have a play with various connectors and extensions.

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

 

I've already been down that route and asked FLO if it will fit my EFW.  Apparently it won't without another adapter adding back to the spacing again and thus defeating the object.

I am going to try in the first instance using my Geotik Canon to CCD adapter again and see if I can get focus with all filters with that as I have finally managed to remove the "foot" which was getting in the way of the EFW when I wanted to screw it on.

Carole 

 

[Hallingskies]

On 04/07/2020 at 16:50, carastro said:

I've already been down that route and asked FLO if it will fit my EFW.  Apparently it won't without another adapter adding back to the spacing again and thus defeating the object.

I am going to try in the first instance using my Geotik Canon to CCD adapter again and see if I can get focus with all filters with that as I have finally managed to remove the "foot" which was getting in the way of the EFW when I wanted to screw it on.

Carole 

 

Would this work for you...?

https://www.modernastronomy.com/shop/accessories/adapters/male-m54-to-m48-female-adapter/

...coupled with this...?

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

I think the adapter should allow you to connect your M54 EFW2 to the FLO M48 Samyang adapter with around 6mm total length.  The EFW2/ATIK 460 combo is around 36mm back focus, with another 2mm for the wheel to camera connector, so you should be at the 44mm focal distance of the Samyang lens.  Apologies if you have already considered this.  

 

 

Edited July 7, 2020 by Hallingskies

[carastro]

That looks very useful Halling skies, and have made a note of it.  I am going to give the original adapter another try first as I am sure it was OK initially, and maybe something just worked loose.

Hate spacing, various threads, and apertures.  

Carole 

 

[Hallingskies]

2 hours ago, carastro said:

That looks very useful Halling skies, and have made a note of it.  I am going to give the original adapter another try first as I am sure it was OK initially, and maybe something just worked loose.

Hate spacing, various threads, and apertures.  

Carole 

 

Hope it works out for you.  I have had a nightmare trying to get an SX-694 (T-threads and a 16mm back focus! 😱) with a manual ATIK filter wheel connected to a Samyang within the 44mm target, but I finally managed it.  You get used to trawling the web for adapters...

[silentrunning]

Finally got my hands on one of these lenses. Been a lot of work learning a new hobby 3D printing to get the FFD down towards the optimal 44mm. I've built adapters for both sides of the SX FW I have. One connects the Lens to the FW, actually bringing the lens into the FW slightly and an adapter for the QHY11 Dew Heater and camera connector on the other side. This one actually mounts inside the wheel although it's all very tight in there, just a 1mm flange and no screws to hold it in place.

After reading this excellent thread I am probably going to go ahead and build an adapter that removes the Canon bayonet completely and will connect directly to the FW,a bit like the one FLO are now selling for the ATIK FW. I might even try to build in adjustable shim ring so I can get bang on the 44mm rather than either side of it. 

This is a single frame and essentially first light I obtained before the clouds rolled in the other night. I'm not sure what to expect at the very periphery of the field at f2 but I have significant aberrations in the outer 3rd of the image, especially one side which makes me think that image tilt is definitely part of the equation. Wether getting closer to the ideal 44mm will smooth things out across the field will have to wait and see. Pleased with progress so far.

No processing other than a stretch.

 

[Adreneline]

I'm coming to the conclusion that the Samyang 135mm + ASI1600 might not be the best combination to capture the Squid nebula within the Bat Nebula (Sh2-129). This is 60 mins of Ha and SII and 180 mins of OIII (all 180s subs).

I'll go for more OIII but I'm not confident I have the resolving power! There again my processing skills may be the limiting factor.

Thanks for looking.

Adrian

 

[Craney]

I am so glad you said that.   I've been trying to wrestle the Squid out of the clutches of darkness for the last 2 weeks.

Even resorting to 10min subs for Oiii ...... unheard of !!!   

I may try a few more (short) nights and do a massive collective stack in APP.

This is the best I got in Oxygen..

This is 3 hours of 600s subs.  (Atik 414ex   which is an amazingly sensitive camera).

 

[Adreneline]

2 minutes ago, Craney said:

Even resorting to 10min subs for Oiii ...... unheard of !!!

10/10 for effort and dedication above and beyond the call! Going for 10mins with the ASI1600 would be a complete waste of time with the Bortle 5 skies I have to deal with here. There is a hint of a squid lurking in both your image and mine but if you didn't know it was there I'm not sure you'd spot it.

Maybe I need to take myself off to a dark sky site one night and see if that helps! - not sure there are any round here  

[Craney]

1 minute ago, Adreneline said:

Maybe I need to take myself off to a dark sky site one night and see if that helps! - not sure there are any round here  

...or get the big guns out......   10" quattro mosaic ...hmmm.... ??....

With the lack of astro-dark, easy planets and that comet distracting all and sundry, it is no hardship grabbing a few more hours.  Line it up and leave it running.   

If you look on Astro-bin some people have invested  32 hours on this thing !!!  🥴