ASI 1600 MM- Cool and Coma Corrector

kaos

I am in need of a coma corrector and am considering the Baader Planetarium 2" Mark III Multi Purpose Coma Corrector. The MPCC requires that you get 55 mm from the sensor to the back plane of the MPCC III.

I am not quite sure how to measure this. My current setup is using 1600MM Cool and the Electronic Filter Wheel mini. They are connected to a LXD75 SN8 (running at f4 (812x203)). I am assuming you attach the MPCC after the EFW in the train. I am not sure what or how much in spacers I need to get to the 55 mm required distance (as I am not sure how much is the total in the 1600MM with the EFW attached). For example, I know the BF of the camera is 6.5mm, but I do not know what the EFW adds and if you have to add the ZWO filter thickness. I would appreciate if you guys can tell me what the starting point is with the camera (and even possibly what spacers I need to get to the 55mm distance).

Thanks

Kaos

rockstarbill

The filter wheel adds 20mm. If you obtained the ZWO OAG (16.5mm) and used the 11mm spacer that came with the camera, and the 1mm T2-T2 adapter that came with the wheel, you would be at 55mm.

kaos

Here is the latest. I found a Baader VariLock 46 T2 Variable Extension Tube - 29 mm - 46 mm.

I actually measured the spacer that came with the camera and it is 18.5 mm. If the EFW from ZWO adds 20mm that would put me at 26.5mm with the back focus of the camera and EFW (20mm + 6.5mm). With the Baader 29-46 the distance would yield 55.5 mm distance (20+6.5+29). Is that close enough or does it have to be exactly 55mm distance? Using all three parts puts it at 45mm (20+6.5 + 18.5). I would need a 10mm extension I suppose.

bvalente

it works if you're not at 55mm, but it works *best* at 55mm

bwallis

Similar issue.... My system has a Field Flattener in it that is set for the back focus of my Canon 6D ( which has a 44mm backfocus distance )... I have just started to use a ZWO 1600mm-c with the 8 position filter wheel... ( I also have the ZWO OAG but have not set up to use it yet ).... I was told that the 1600mm-C with the filter wheel and the ZWO adapter for a canon EOS would match my optics and would also let me use Canon lenses. However I'm not AT FOCUS with this setup and I think I must need some additional spacers in order to get this to work. Is it possible to add in the ZWO OAG and still reach focuse. Comments / Help greatfully accepted !! B Wallis

Sam@ZWO

Kaos wrote:
Here is the latest. I found a Baader VariLock 46 T2 Variable Extension Tube - 29 mm - 46 mm.

I actually measured the spacer that came with the camera and it is 18.5 mm. If the EFW from ZWO adds 20mm that would put me at 26.5mm with the back focus of the camera and EFW (20mm + 6.5mm). With the Baader 29-46 the distance would yield 55.5 mm distance (20+6.5+29). Is that close enough or does it have to be exactly 55mm distance? Using all three parts puts it at 45mm (20+6.5 + 18.5). I would need a 10mm extension I suppose.

there is one 11mm M42 externtion come with the camera

martinf

I have also bought a Zwo ASI1600MM with the 8-position filter Wheel.

I have a Baader MPCC mkIII. Will I need additional spacers to make it work? If I can´t get to exactly 55mm, would 52,5 or 57 work?