Pairing the asi2600mc duo with a Samyang 135mm lens ZWO ASI2600MC DUO · Bruno Figueira · ... · 89 · 4451 · 39

Michelle Roosette:
So, I have tested the Duo with the Rokinon 135 lens with both the M54 and M42 adapters. Both guide very well. My current issue now is that I’m still getting vignetting/light dropoff. It seems to be my surrounding lights, since I get the same effect with all of my canon lenses.

Michelle I am struggling and over here as we speak. I think the imaging circle of the samyang 135 is small because I’m getting vignetting and I’m also not able to find focus. What did you do differently?

Michelle Roosette:

Andy:

Michelle Roosette:
So, I have tested the Duo with the Rokinon 135 lens with both the M54 and M42 adapters. Both guide very well. My current issue now is that I’m still getting vignetting/light dropoff. It seems to be my surrounding lights, since I get the same effect with all of my canon lenses.

Michelle I am struggling and over here as we speak. I think the imaging circle of the samyang 135 is small because I’m getting vignetting and I’m also not able to find focus. What did you do differently?

**Andy, the vignetting and focusing are two separate issues. As for focusing, I had no trouble at all. I saw the picture of your imaging train above. Did you ever add a small shim/extender (less than 1mm) to your rig?  Adding additional spacing to accommodate for the lens would be necessary. If you're still having trouble focusing, try without the filter wheel and add back the 15mm and 5mm tilt plate back to see if it makes a difference?  Good thing is that you can test all this in the day time and not have to wait for a clear sky. I'm sure you'll get to the bottom of it. Let us know how it goes!

Thank you! I added a .6mm fine adjustment spacer bringing my bf to 44.6. Also, the above screenshot of the image is from the guide sensor. I was able to achieve focus with the main sensor fairly quick- no issues. It’s the guide sensor that I can’t get focused and also the vigenetting you see. I’ll troubleshoot tomorrow.

What’s your imaging train now look like? I presume you’re not running a filter wheel…

Michelle Roosette:

Andy:

Michelle Roosette:

Andy:

Michelle Roosette:
So, I have tested the Duo with the Rokinon 135 lens with both the M54 and M42 adapters. Both guide very well. My current issue now is that I’m still getting vignetting/light dropoff. It seems to be my surrounding lights, since I get the same effect with all of my canon lenses.

Michelle I am struggling and over here as we speak. I think the imaging circle of the samyang 135 is small because I’m getting vignetting and I’m also not able to find focus. What did you do differently?

**Andy, the vignetting and focusing are two separate issues. As for focusing, I had no trouble at all. I saw the picture of your imaging train above. Did you ever add a small shim/extender (less than 1mm) to your rig?  Adding additional spacing to accommodate for the lens would be necessary. If you're still having trouble focusing, try without the filter wheel and add back the 15mm and 5mm tilt plate back to see if it makes a difference?  Good thing is that you can test all this in the day time and not have to wait for a clear sky. I'm sure you'll get to the bottom of it. Let us know how it goes!

Thank you! I added a .6mm fine adjustment spacer bringing my bf to 44.6. Also, the above screenshot of the image is from the guide sensor. I was able to achieve focus with the main sensor fairly quick- no issues. It’s the guide sensor that I can’t get focused and also the vigenetting you see. I’ll troubleshoot tomorrow.

What’s your imaging train now look like? I presume you’re not running a filter wheel…

Andy, you’re right… no filter for me. I just have the canon bayonet 11.5mm, M54 extender 15mm, and the 17.5mm camera. I want to add a filter, but I need to add a 0.6mm spacer. Where did you get yours??

 What settings do you have on your guiding? That screenshot looks strange - perhaps over exposed?

I overexposed slightly so you can see the vignetting. I don’t use my tilt plate so I will just use my 16.5 adapter and fine adjustment rings. Here’s a link to the adjustment rings that I use:

1) https://www.google.com/aclk?sa=l&ai=DChcSEwj3ntrB--uEAxWeXkcBHbEYDf0YABAPGgJxdQ&gclid=CjwKCAjw17qvBhBrEiwA1rU9wxKQ-rrXWZvSkIZxGh-T-pO-ly1eHQPEjgmTJ1FxPqMs0WdKy4WTghoCZ-oQAvD_BwE&sph=&sig=AOD64_29pRC5CGSvkrEOIJcpbB6cDUHvKg&ctype=5&q=&ved=2ahUKEwiS0tTB--uEAxXUjokEHZ50CxMQwg8oAHoECAMQDA&adurl=

2) https://www.google.com/aclk?sa=l&ai=DChcSEwj3ntrB--uEAxWeXkcBHbEYDf0YABAXGgJxdQ&gclid=CjwKCAjw17qvBhBrEiwA1rU9w0vGAjweT1qQh6ddBRWMXE2FIVnO_1ilk7Vm4cfuzJjibltaHF-lahoCjgoQAvD_BwE&sig=AOD64_3BlxWpnMXUG_iNELYMz_BfTE3txQ&ctype=5&q=&ved=2ahUKEwiS0tTB--uEAxXUjokEHZ50CxMQwg8oAHoECAMQLA&adurl=

Richard Gifford:
I used the ZWO to eaf adapter to connect to the Canon 135 F2 and works well.

Just need to mount the lens and camera and hoping I can find a suitable bracket.

@Michelle Rousset@Richard Gifford i was able to achieve focus at 42.5mm

11.5 T2 efw adapter + 9mm adapter + 4.5 fine adjustment rings+ 17.5mm (ccd). No vignetting and my guide sensor is fully illuminated. I’m upset that I can’t use my efw though as I have the Colormagic d1/d2 filters for narrowband. I’m going to trouble shoot the filter wheel again and see what happens.

Michelle Roosette:

Andy:

Michelle Roosette:

Andy:

Michelle Roosette:

Andy:

Michelle Roosette:
So, I have tested the Duo with the Rokinon 135 lens with both the M54 and M42 adapters. Both guide very well. My current issue now is that I’m still getting vignetting/light dropoff. It seems to be my surrounding lights, since I get the same effect with all of my canon lenses.

Michelle I am struggling and over here as we speak. I think the imaging circle of the samyang 135 is small because I’m getting vignetting and I’m also not able to find focus. What did you do differently?

**Andy, the vignetting and focusing are two separate issues. As for focusing, I had no trouble at all. I saw the picture of your imaging train above. Did you ever add a small shim/extender (less than 1mm) to your rig?  Adding additional spacing to accommodate for the lens would be necessary. If you're still having trouble focusing, try without the filter wheel and add back the 15mm and 5mm tilt plate back to see if it makes a difference?  Good thing is that you can test all this in the day time and not have to wait for a clear sky. I'm sure you'll get to the bottom of it. Let us know how it goes!

Thank you! I added a .6mm fine adjustment spacer bringing my bf to 44.6. Also, the above screenshot of the image is from the guide sensor. I was able to achieve focus with the main sensor fairly quick- no issues. It’s the guide sensor that I can’t get focused and also the vigenetting you see. I’ll troubleshoot tomorrow.

What’s your imaging train now look like? I presume you’re not running a filter wheel…

Andy, you’re right… no filter for me. I just have the canon bayonet 11.5mm, M54 extender 15mm, and the 17.5mm camera. I want to add a filter, but I need to add a 0.6mm spacer. Where did you get yours??

 What settings do you have on your guiding? That screenshot looks strange - perhaps over exposed?

I overexposed slightly so you can see the vignetting. I don’t use my tilt plate so I will just use my 16.5 adapter and fine adjustment rings. Here’s a link to the adjustment rings that I use:

1) https://www.google.com/aclk?sa=l&ai=DChcSEwj3ntrB--uEAxWeXkcBHbEYDf0YABAPGgJxdQ&gclid=CjwKCAjw17qvBhBrEiwA1rU9wxKQ-rrXWZvSkIZxGh-T-pO-ly1eHQPEjgmTJ1FxPqMs0WdKy4WTghoCZ-oQAvD_BwE&sph=&sig=AOD64_29pRC5CGSvkrEOIJcpbB6cDUHvKg&ctype=5&q=&ved=2ahUKEwiS0tTB--uEAxXUjokEHZ50CxMQwg8oAHoECAMQDA&adurl=

2) https://www.google.com/aclk?sa=l&ai=DChcSEwj3ntrB--uEAxWeXkcBHbEYDf0YABAXGgJxdQ&gclid=CjwKCAjw17qvBhBrEiwA1rU9w0vGAjweT1qQh6ddBRWMXE2FIVnO_1ilk7Vm4cfuzJjibltaHF-lahoCjgoQAvD_BwE&sig=AOD64_3BlxWpnMXUG_iNELYMz_BfTE3txQ&ctype=5&q=&ved=2ahUKEwiS0tTB--uEAxXUjokEHZ50CxMQwg8oAHoECAMQLA&adurl=

*Thanks for these links, Andy! Not sure why I didn’t think of spacers like those!

Thank you to you and everyone who has chimed in on this thread. I am off to the races! We are in business with the Samyang 135 and the 2600mc duo is a match made in heaven. I can't believe just a .6 fine adjustment ring completely threw off the focus point for the guide camera on the duo! My bf is right at the 44mm! Both the main and guide sensor are dialed in. Also, I retained my filter wheel— really just needed to removed the .6 adjustment ring.😅

Richard Gifford:
I used the ZWO to eaf adapter to connect to the Canon 135 F2 and works well.

Just need to mount the lens and camera and hoping I can find a suitable bracket.

[email]*@richardgifford[/email] Seems like you will not have enough distance between the lens and the camera sensor? Here you only have the 11.5 from the bayonet plus 17.5 from the camera... you need 44mm.  Let us know how that goes. As for the bracket/rings, what do you have currently?

Bruno Figueira:
Hj everybody, new updates on this topic

Just received my 2600MC Duo today.

First test inside the house. 

ASI2600MC Duo paired with Samyang 135mm lens and a ZWO Nikon Filter Drawer (M42 on camera side).
First test shows the guide camera sensor fully illuminated (see image attached). I'll try a test with stars tonight if weather permits

I'll keep you updated

*Excellent, Bruno!  You should have no trouble finding guide stars!  Looking forward to seeing what you are able to capture!

Bruno Figueira:
Hi people

Just tried a test shot under the stars and the clouds and a lot of light pollution and a very bad seeing but I was able to find stars and confirm that my Samyang 135mm with the ZWO NIKON Filter Drawer (M42) is able to fully illuminate the guide sensor in my 2600MC Duo (see photo). More to come in the weekend

Clear skies 

*Bruno, all of our (my!) worrying for nothing! 😁 It’s good to know. I’m excited to start some imaging!

Chris Todd:

Andy, you’re right… no filter for me. I just have the canon bayonet 11.5mm, M54 extender 15mm, and the 17.5mm camera. I want to add a filter, but I need to add a 0.6mm spacer. Where did you get yours??

 What settings do you have on your guiding? That screenshot looks strange - perhaps over exposed?

Michelle, where did you obtain an M54 to M54 15mm long adapter? I am trying to do the same with the Roki 135, ZWO EOS adapter/bayonet, and 2600MC DUO, and the EOS adapter came with an M54-M42 that does not pair with the 2600MC DUO.

Hi Chris!  Sorry for the delay in responding. I got mine from Agena Astro... Here's the link  https://agenaastro.com/blue-fireball-m54x0-75-spacer-ring-with-15mm-extension.html I hope that helps!

Hi Bray, did you notice any issues / loss in contrast with bandshifts at f/2.2?

I ordered the two Altair Duo Narrowband filters to image HaOIII and SIIOIII together at 6nm. Because of bad weather I couldn't test those yet, but I hope they will perform well also at lower f ratios.

Best,
David

Hi @Dcolam , I use the highspeed version of dual band. I never performed a comparison, but at f/2, as you correctly anticipate, has to be expected that the normal filters have a low transmission rate. BTW, HaOiii High Speed are available (Antlia and Optolong for instance), I have not yet found any SiiOiii or SiiHb Highspeed version.

​​Hi ​@Mau_Bard, thanks for your reply. In the meantime, I could test out the dual NB filters mentioned before with the Samyang. I am not super impressed by the SIIOIII filter but that might also be due to the low angular resolution of the Samyang and the typically lower SNR of SII objects or SII bandwidth being more red-shifted suffers significantly more in signal reduction due to fast f-ratio band-shift.

In any case, I find myself using the HaOIII much more, you can see some pictures I took with it in my gallery but did not post all of them that I took (yet). I wonder how much more efficient it would be to have pre-shifted filters.

After much experience with my Samyang 135mm, I’ve concluded that you always need to ensure bf is 44mm. Using 2” filters, particularly narrowband for mono imaging will require your total bf at 45mm. Otherwise, if using a OSC, then your starting bf is 44mm then add a .6mm fine-tuning spacer ring to adjust for your filter (I recommend 2” so you’re “future” proof) bringing your total bf to 44.6mm. Attached is my current setup. Below are two vendors for the fine tuning adjustment rings—one of the best purchase I’ve made!

my current setup below is for sale on CN; $675. not included: imaging train and ASI Air+
vendors: 
1) https://www.bhphotovideo.com/c/product/1406346-REG/alpine_astronomical_t2ring_baader_t_2_15_piece_delrin.html

2) https://www.etsy.com/listing/1120536216/astrodymium-color-coded-spacer-rings-for?gpla=1&gao=1&&utm_source=google&utm_medium=cpc&utm_campaign=shopping_us_c-electronics_and_accessories-other&utm_custom1=_k_CjwKCAjw0t63BhAUEiwA5xP54cVweLjtFW2QPnjYVrJHi34SuF64R-3pHuWNuaaGL42Nqzlasx7nrRoCT98QAvD_BwE_k_&utm_content=go_12559942231_125052052208_506949395494_pla-315906365691_m__1120536216_12768591&utm_custom2=12559942231&gad_source=1&gbraid=0AAAAADtcfRK-MO7ZMrExTmowURw4M7WRn&gclid=CjwKCAjw0t63BhAUEiwA5xP54cVweLjtFW2QPnjYVrJHi34SuF64R-3pHuWNuaaGL42Nqzlasx7nrRoCT98QAvD_BwE

Bruno Figueira:
Hi people

Just tried a test shot under the stars and the clouds and a lot of light pollution and a very bad seeing but I was able to find stars and confirm that my Samyang 135mm with the ZWO NIKON Filter Drawer (M42) is able to fully illuminate the guide sensor in my 2600MC Duo (see photo). More to come in the weekend

Clear skies 

Bruno, I just picked up the 135 Samyung and already own the Nikon Adapter/filter drawer. I am really hoping to use this with the asi2600mc duo and it sounds like you had success. Did you need to do any tweaking? If I just use the adapter with the included ring that changes it from M42 to M54, am I ready to hit the ground running?

Michelle Roosette:

Chris Todd:

Andy, you’re right… no filter for me. I just have the canon bayonet 11.5mm, M54 extender 15mm, and the 17.5mm camera. I want to add a filter, but I need to add a 0.6mm spacer. Where did you get yours??

 What settings do you have on your guiding? That screenshot looks strange - perhaps over exposed?

Michelle, where did you obtain an M54 to M54 15mm long adapter? I am trying to do the same with the Roki 135, ZWO EOS adapter/bayonet, and 2600MC DUO, and the EOS adapter came with an M54-M42 that does not pair with the 2600MC DUO.

Hi Chris!  Sorry for the delay in responding. I got mine from Agena Astro... Here's the link  https://agenaastro.com/blue-fireball-m54x0-75-spacer-ring-with-15mm-extension.html I hope that helps!

Michelle , I saw towerw dealing with vignetting. Ive spent 2 nights trying to save it too. I've got focus  dialed in and get great guidng with the duo. But then vignetting and ight drop off is terrible. Ultimately, how did you solve it? I've tried stepping down to f 3.2 but still the vignetting is horrible. Any advice?