Matched vs mismatched dual rig

[Marmo720]

Really appreciate the discussion and I am learning so much - thanks all! 

At the moment, my planned setup (and I welcome comments/feedback!) is shown below. The resolution range is between 1.4-1.6 per pixel and so hoping the scale is close enough to not notice the difference once combined and processed. 

I have read that Pixinsight can register and stack subs from different telescopes like this but not had the chance to test this. Is that true or would I need Registrar?

[sloz1664]

26 minutes ago, Anne S said:

Do you need to shim the upper scope to get the fov matched? I tried running an Altair Wave102 with an Altair Starwave 70EDT a year or so ago and found they were fairly close, particularly as the upper scope had a larger fov. Also, do you have any problems with higher altitude targets and the upper scope? I've the same dome as you, the early Pulsar 2.1.

I gave up with the dual rig at the time as I had an issue with the reducer on the Wave. I want to try again now I've fixed that and upgraded my mount.

Hi Anne, Yes I spent time shimming both scopes and now have them aligned. Regarding the upper scope and alignment, I presume you mean it's position relative to the shutter. I altered the "Mount pivot point to the optical centre" dimension to incorporate both scopes, ie half the measurement from the bottom scope tube to the top of the upper scope tube. This then places both scopes central to the dome slit.

Hth

Steve

[Anne S]

16 hours ago, sloz1664 said:

Hi Anne, Yes I spent time shimming both scopes and now have them aligned. Regarding the upper scope and alignment, I presume you mean it's position relative to the shutter. I altered the "Mount pivot point to the optical centre" dimension to incorporate both scopes, ie half the measurement from the bottom scope tube to the top of the upper scope tube. This then places both scopes central to the dome slit.

Hth

Steve

Thanks for that information. One other question, do you have any issues with the top scope not being able to see the target because it's behind the top of the shutter? I found that once or twice. Possibly something to do with where I'd positioned the upper telescope. I notice you've got your guide scope right at the front of the setup, presumably for the same reason.

[sloz1664]

Hi Anne, That's not a guide scope it's a 135mm lens. I use an OAG connected to the second mounted scope and as I have adjusted the mount pivot point value, this all but eliminates any shutter issues.

Steve

[Marmo720]

I thought I would ask here instead of new topic - what is the ideal setup for dual rig with 1 set of LRGB HaSiiOii? I can't afford to double up on some of the narrowband filters so checking how to maximise with 1 set.

Current thinking is:

Telescope 1 - RGB Sii Oiii

Telescope 2 - LHa

Thanks,

Mo