Idea for Mono/colour twin planetary camera set up

[michaelmorris]

I've had on the excellent Imaging Source  DMK21 618 AS mono planetary cameras for a few years now and I'm really pleased with it. Earlier this year I got the chance to get hold of the colour (DBK) version of the earlier 21 series camera at a knock down price.

For planetary imaging, I'm starting to experiment with taking high res luminance images with the mono camera and get the colour data from the cheaper colour camera.  As I've found out already, the biggest pain is swapping cameras and the subsequent refocusing.  This evening it struck me that the simplest way around this would a mechanism to simply mechanically move the two cameras in and out of the light path.  The first solution that came to mind is a flip mirror. However I'd be introducing another optical surface in the light path and would have to do a digital flip of one of the images to get them to line up.

Would an eyepiece rotator like the Baader Q turret http://www.firstlightoptics.com/misc/baader-q-turret.html be accurate enough in lining up each camera exactly square with the light path?

Thanks

[Pete Presland]

It might asking in the observing threads if anyone has used one visually it would give an idea about the build quality of the item and how well it functions.

[Space Cowboy]

Ive used a wheel for my 2 cameras but mine is a cheap model and needed tightening up to reduce some slop. A better model would probably work very well like the one on your link.

[Steve Ward]

Would a binoviewer not work ... ?

There'd be a light-loss issue with the beam being split , but for planetary I'd have thought this could be worked round by adjusting capture settings.

[Space Cowboy]

Any light loss would seriously compromise capture performance. The biggest issue for me is the faff of not being able to run both cameras at the same time as the capture software needs closing each time to use each camera and without disconnecting the USB every time the software will freeze.

One issue of having both cams sitting in a wheel is dew.

[michaelmorris]

I managed to try out a Baader Q turret on Monday (thanks Helen)

Unfortunately having two heavy Imaging Source cameras hanging off the back of the turret causes the two plastic parts to separate very slightly, meaning the imaging chip on the cameras are no longer lined up perpendicular to the light cone. This leads to a slight difference in focus from the top to the bottom of the image.   Whilst I suspect that this may not have a dramatic effect at the long focal lengths used in planetary imaging, I think it is enough to make a small difference. Shame.

Looks like it's going to be a flip mirror system then.  Any suggestions as to the best value for money flip mirrors?

[Kokatha man]

I was going to respond to this thread before but I seem to have a lot of trouble at times logging in to SGL...

We have been investigating this same issue & trying to save money, & have hesitated getting someone to fabricate something made with fine tolerances - as you have noted with this Baader device one needs to be confident that collimation remains stable when switching between cameras: incidentally, your "slight difference in focus" is both a focus & collimation issue & utterly unacceptable for us - re-collimating when changing over isn't much less work than swapping cameras in & out imho.

We are awaiting a reply to our enquiries with a European AA accessory maker & will report back when we get the relevant info...at present we would like to run the ASI174MM & ASI224MC side-by-side & if we can purchase something "off the shelf" it would be great...we looked at employing another filter wheel in the train to effect this operation but it appears as if this might be OTT.

[ollypenrice]

Now Michael, the answer is marvellously obvious. You need a second telescope. 

Joking aside, as a non planetary imager I wonder why we don't see more of this. An old SCT OTA isn't a hugely costly thing to pick up and working simultaneously would have huge advantages in defeating planetary rotation. Wouldn't it? As I say, I don't do this kind of imaging.

Olly

Edit. I guess one problem would be aligning them. A second hand Cassady T-GAD would do it but might cost more than a second hand OTA!

[michaelmorris]

Now Michael, the answer is marvellously obvious. You need a second telescope. 

Joking aside, as a non planetary imager I wonder why we don't see more of this. An old SCT OTA isn't a hugely costly thing to pick up and working simultaneously would have huge advantages in defeating planetary rotation. Wouldn't it? As I say, I don't do this kind of imaging.

Olly

Edit. I guess one problem would be aligning them. A second hand Cassady T-GAD would do it but might cost more than a second hand OTA!

A second OTA also = a new mount and a larger observatory!  (+ bankrupcy and possible divorce)  I'm afraid a second OTA is completely out of the question.