What order should items be placed in the imaging train

[Uplooker]

Hi all,

For capturing DSOs I currently use a Sky Watcher 6” F5 newt, to which I have fitted a Revelation Dual speed focuser. I use an unmodified Canon 450D, which I attach to my scope using a Max DSLR 2 inch camera adaptor as per the link.

http://www.scopesnsk...amera/DSLR.html

I which to improve things by adding a coma corrector and a light pollution filter.

For the coma corrector the Baader MPCC seems to be the one to go for. There are two versions – visual and photographic. I am not informed enough to be sure on which to go for – as obvious as it may seem, photographic or visual???

For the light pollution filter I am unsure but it seems to be between Baader, Sky Watcher and CLS Light pollution Clip filter.

to aid my decision in what to purchase I would be very grateful if people could advise me as to what order or how to include these items in the imaging train

Regards,

Ian

[The Sailor]

Good subject Ian, something I have wondered myself, the other night I put a dustcap on and wondered why I could not see anything, half hour to figure that one out!!!

Jim

[Black Knight]

If you only intend to use your coma corrector for imaging, just buy the imaging kit. The visual kit contains adapters etc to use the MPCC with eyepieces. I don't know about the Baader filter, but the Astronomik clip-in filter is reputed to give the best results. Personally I use a 2" Skywatcher LP filter, simply because it was way cheaper than the Astronomik!

How you fit it all together depends on which kit you end up with, but mine goes like this:

Canon DSLR -- Canon T-ring -- Coma corrector -- 2" LP filter

Obviously, if you have the clip-in filter, that goes inside the Canon body!

[Uplooker]

Hi All,

Thanks for your replies

Andy,

As I have the 2 inch camera adaptor, which is threaded, would I just screw the MPCC into the bottom of of the adaptor?

I am sure I have seen writings about the need to be careful of the spacing between the coma corrector and the camera sensor, is this the case? How do you find out the correct distance - more research required me thinks.

Ian

[Black Knight]

Hi All,

Thanks for your replies

Andy,

As I have the 2 inch camera adaptor, which is threaded, would I just screw the MPCC into the bottom of of the adaptor?

I am sure I have seen writings about the need to be careful of the spacing between the coma corrector and the camera sensor, is this the case? How do you find out the correct distance - more research required me thinks.

Ian

The required spacing is 55mm between the MPCC flange and the plane of the sensor inside the camera. If the 2" adapter you are referring to is the MaxDSLR in the link you posted, then I believe that is a one-piece unit. In which case, to use the MPCC you'll need a separate Canon T-ring like this : http://www.firstlightoptics.com/adaptors/t-rings.html to attach to the MPCC.

This Baader doc should help explain things probably better than I can! : http://www.baader-planetarium.com/pdf/mpcc_e.pdf