Pairing the asi2600mc duo with a Samyang 135mm lens ZWO ASI2600MC DUO · Bruno Figueira · ... · 65 · 2341 · 30

Andy:

Michelle Rousset:
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:

Michelle Rousset:

Andy:

Michelle Rousset:
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:

Michelle Rousset:

Andy:

Michelle Rousset:

Andy:

Michelle Rousset:
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=

Andy:

Michelle Rousset:

Andy:

Michelle Rousset:

Andy:

Michelle Rousset:

Andy:

Michelle Rousset:
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.😅