Imaging with the Samyang 135mm f2

[SAW]

Finally processed some data with the Samyang 135mm and 2600MM. Still can't get nice stars in the corners 😢

NGC2244.tif

[Adreneline]

1 hour ago, SAW said:

Finally processed some data with the Samyang 135mm and 2600MM. Still can't get nice stars in the corners 😢

NGC2244.tif 137.36 MB · 6 downloads

It's almost like the spacing is too great (if you were using a conventional flattener) ....

.. and I'm not sure how best to interpret this ...

... I tend to look for symmetry rather than get too worked up about absolute values.

Adrian

[Petrol]

Barnard's loop 3 panel mosaic with an ASi 294MC pro. I used a ZWO dual band filter which I've read are not recommended with a wide FOV  😮 Processed in Pixinsight. RC astro plugins helped a lot.
All comments and feedback is welcome. I'm new to most of this technology and this is my first mosaic and multi night imaging session.
Thanks for looking.

Pete


 

[SAW]

Is it 2 clicks or 3 clicks to get to f/2.8 from f/2 on this lens ?

[powerlord]

On 28/02/2023 at 22:38, Petrol said:

Barnard's loop 3 panel mosaic with an ASi 294MC pro. I used a ZWO dual band filter which I've read are not recommended with a wide FOV  😮 Processed in Pixinsight. RC astro plugins helped a lot.
All comments and feedback is welcome. I'm new to most of this technology and this is my first mosaic and multi night imaging session.
Thanks for looking.

Pete


 

looks like the ZWO filter did all right to me!

stu

[SAW]

Reduced my spacing around 0.8-1mm I can't get any closer now. Also shot at f/4 and stars are a lot better but still have some elongated ones on the left side of the image. Single 300s ha sub. i might try adding a 0.5mm shim next time.

Edited March 2, 2023 by SAW

[SAW]

Playing around with some narrowband data. Very little on the Oiii and Sii data though ! Large crop as well.

[aleixandrus]

On 01/03/2023 at 22:54, SAW said:

Is it 2 clicks or 3 clicks to get to f/2.8 from f/2 on this lens ?

2 clicks per stop if I'm not wrong. However, I'm using a 77>49mm step down ring.

On 02/03/2023 at 23:12, SAW said:

Reduced my spacing around 0.8-1mm I can't get any closer now. Also shot at f/4 and stars are a lot better but still have some elongated ones on the left side of the image. Single 300s ha sub. i might try adding a 0.5mm shim next time.

Much (much) better than mine! I think I'll need to check spacing again  🥲

[barbulo]

Issue with autofocusing: after gradually increasing the spacing while seeking the correct back focus distance, the focus point became so close to the hard stop that I cannot run the autofocusing routine in NINA. Focus point now is around position 150 and my optimal step size is 50~70 steps. 
Anyone facing the same problem? 
I’ve seen Nico Carver’s video on how to move the hard stop to allow “beyond-infinity” focus but I’m not sure if I should do the surgery. Any thoughts?

Tanks in advance.

[powerlord]

Don't use nina, but in asiair the solution is to change the direction of af routine to work out, not in.

[barbulo]

7 hours ago, powerlord said:

Don't use nina, but in asiair the solution is to change the direction of af routine to work out, not in.

Thank you very much @powerlord. I already have it in the right direction but the routine needs more travel “inwards” to calculate the curve. 

[ollypenrice]

Here's our new mounting setup following the total failure of the abominable Wega mounting bracket, which continued to fall apart. As we are desperately trying to finish a project on Orion I wanted to use only bits of hardware I had in stock or could make. So...

A Losmandy to Vixen adapter holds a Vixen rail to which two hefty Altair Astro guide rings are attached. These carry the scope-camera. Bolted to the front of the Vixen rail is a homemade piece of alloy angle with slotted holes for tension adjustment as it carries the focus motor.  The belt which came with the Wega has the same pitch as the ribbing on the focus barrel so there is no need for the Wega pulley, which also fell apart.  In practice the fine tuning of the belt tension is best done using the adjusters of the Altair guide rings. An old Vixen rail is then bolted to the guide rings and carries a Skywatcher finder guider.

I'm not a fan of guide rings but this, so far, is nice and stiff and I've used the Altair guide rings for several years on another rig so I trust them. There will be cone error using guide rings but, on an Avalon M-Uno, there are no meridian flips so I don't expect it will matter.

[ollypenrice]

New Samyang image here: 

Olly

[Laurin Dave]

4 hours on the Pleiades from November 2022, Samyang135 at f2.8 and ASI2600mc, gain zero minus10 300second subs.  Processed in Pixinsight :- calibration, cosmetic correction, debayer, reg, NSG, integration, DBE, Spectrophotometric colour calibration, BlurExterminator, StarExterminator, NoiseExterminator and stretching (ArcSinh, HT and GHS)) and Photoshop for colour enhancement, combining various levels of stretch and adding the stars back using Screen mode,

Thanks for looking 

Dave

[ollypenrice]

Gorgeous and super-subtle. I really like the warm colours of your dust.

Olly

[tomato]

Great processing, and a first class image.👍

[Laurin Dave]

14 hours ago, ollypenrice said:

Gorgeous and super-subtle. I really like the warm colours of your dust.

Olly

Thanks Olly..   Dust colour courtesy of balancing the red and green in the Histogram rather than removing the green with scnr, then boosted with the LAB colour Soft light method you showed me 

13 hours ago, tomato said:

Great processing, and a first class image.👍

Thanks Steve

[LaGuille]

Hi guys, 

I'm happy to share with you my last image of the HorseHead Nebula & Orion, took with my Samyang 135mm at F/2.8. 4H of exposure, under a Bortle 4 sky, in France 🇫🇷

📸 Canon 100D moded ⚙️ Star Adventurer💡 L-Enhanced Filter 💻 Siril + Pixinsight + Photoshop

 

Have a great day !

[glafnazur]

That's a great image, thanks for sharing 👍

[Petrol]

I liked my 294MC pro / Samyang setup but my out of warranty 294 packed up and it wasn't cost effective to repair. Basically the PCB went and they suggested I replace it myself with no warranty. It was a no brainer to buy a camera from another manufacturer so I went for a Player One. It was also a good time to have a rebuild of my mobile rig. The cables were getting messy and I've chopped and changed things over the years. This Skywatcher EQ5 mount is over 10 years old, been hammered to death but it's still going strong.  I had to upgrade the USB hub due to the bigger file size from the Poseidon camera and finding a 12V USB 3 hub was not as easy as I thought. This Star Tech hub looks like it will do the trick though. For once, I'm ready in advance!
I usually hate winter but for once, I can't wait to try this rig out.


Thanks for looking
Clear skies
Pete

[900SL]

I've put together a lightweight rig to take on holiday, Nikon F Mount 135mm and ZWO adapter, this will sit on a Fornax LT2 so no guiding, step down ring, I might manually dither every 3-5 frames.

I have a couple of questions. The backspacing to the ASI sensor is 46.5mm and I will use either a Ha/Oiii dual narrowband or a UV/IR L3 filter.

Do I need to add spacer rings to increase the backfocus to suit, or will it still come to focus (ie which way does the focus move when adding a filter, farther out past infinity or closer in?) 

I've forgotten the second question  😄

[Elp]

Ideally you'd want to physically add the spacing in, but I find I can focus fine at the standard backspacing. I do have a set of 0.2/0.5/1 mm rings just in case.

Edited May 12, 2023 by Elp

[LaGuille]

Hi everybody !

Would someone be so kind as to summarize what rings I need to use with my Samyang 135mm Canon, to a 294 mc pro, using this 21mm drawer :

https://www.pierro-astro.com/materiel-astronomique/accessoires-astronomie/roues-à-filtres-et-accessoires/support-filtres-à-tiroirs-m48-vers-t2-pour-filtres-50,80mm-m48-zwo_detail

Thanks for your help. 
I know there are a lot of experts hanging out here! 

Damien 

Edited May 15, 2023 by LaGuille

[JOC]

Well I'm not using your kit, but to attach my Canon to a standard telescope focusser I needed to buy something called a T ring - like this one https://www.wexphotovideo.com/celestron-t-ring-for-canon-dslr-cameras-1534225/?cpgnid=17651495694&adext=&account=853-353-2386&campaign=&group=&mkwid=_dc&pcrid=&kword=&match=&plid=&pgrid=&ptaid=&si=&gclid=Cj0KCQjwsIejBhDOARIsANYqkD2qr7NaUXkBQeH0SmPAJCF7ol1JSYbJ3-tQAxJQmlnt6U2PlVg6450aAtT_EALw_wcB  

I found a combination of this, with the adapters from the focus unit (the 1.25" and 2") and, though it sounds daft, some useful bits which unscrewed from a small barlow unit I had successfully attached the camera to my telescope and it got focus.  I suspect at the very least you might well need a Canon T ring - even though I appreciate that is entirely different kit to what I use, but you will need something that mates up with the lens locking thread/machanism on the camera and that's a T ring.  Then it might be worth a fumble around your 'bits box' (I bet you have one!) to see if anything will usefully take apart to give you what you need prior to buying anything else.

Edit - Just had another thought, you only want to attach the lens don't you?  You sort of need a reverse T ring if such a thing exists.

Edited May 15, 2023 by JOC

[Budgie1]

2 hours ago, LaGuille said:

Hi everybody !

Would someone be so kind as to summarize what rings I need to use with my Samyang 135mm Canon, to a 294 mc pro, using this 21mm drawer :

https://www.pierro-astro.com/materiel-astronomique/accessoires-astronomie/roues-à-filtres-et-accessoires/support-filtres-à-tiroirs-m48-vers-t2-pour-filtres-50,80mm-m48-zwo_detail

Thanks for your help. 
I know there are a lot of experts hanging out here! 

Damien 

If you haven't already got the filter drawer then ZWO make a filter drawer to fit the Canon lenses and no other spacers are needed. Here's the link: https://www.firstlightoptics.com/zwo-accessories/zwo-filter-drawer-for-canon-eos-lenses.html

Alternatively, you can remove the Canon attachment ring on the lens and replace it with an Astro Essentials M48 threaded attachment so you can screw the filter drawer & spacers directly onto the lens. This makes for a more secure connection but I'm not sure which spacers you would need.