UWAN 28mm + Baader MPCC

[MikeNZ]

Hi all
I've just received a new WO UWAN 28mm and I would dearly love to be reporting on the clarity of the optics, the wonderful flat field and the beautiful colour rendition .... but it's been cloudy for the past 3 nights :sadeyes:

So, to wile away a little time I've been attempting to connect a Baader Coma Corrector without success. WO have confirmed the 28 accepts a 48mm filter thread, and the Baader sports an M48. They also advised that they may have a different pitch which would explain my difficulty.

Does anyone have experience with this coupling?

[Mrkex]

I dont have any experience with these items but I do know about threads and pitches. There are 2 metric threads, course and fine. Course thread at 48mm has a pitch of 5mm, pitch means how far apart the threads are, so I would say it is not that so it must be a fine thread which has a 2mm pitch. It should be easy to see if they are different.
The fine pitch threads are easy to cross thread and if this is the case it can be tricky to fix. I would suggest to take it to someone and try it in another eyepiece or try another filter and see which one has the problem.

Mark

[MikeNZ]

Hi Mark
Thanks for your advise. The thread on the 28 does appear very fine indeed, so I'm guessing it's 2mm. While the MPCC does look a little wider it's certainly not 5mm. I can confirm that the MPCC isn't cross threaded, as it has a flange which is removed to expose the thread and the action is smooth.

That only leaves the UWAN :( I don't have any 2" filters but I'll try and get my hands on one to test. It's brand new of course, direct from the manufacturer.