Fitting a Baader Hyperion on a Olympus camera with Micro 4/3 mount

[Mikkel]

Here's a question from a happy astro-amateur from Denmark.

I currently own a Sky-Watcher Explorer 130/900 and I think about making a setup with that and my Olympus OMD E-M10 MKII for some astrophotography. The camera has a micro 4/3 lens mount. I have been using my scope for a couple of years though I'm very experienced but I am a complete novice when it comes to AP. 
I've read good reviews of the Baader Hyperion eyepieces and think that a 21mm would be nice and it has M43 and T2 photo threads.
So my questions are these:

1. How do I fit the camera on the eyepiece (adapter or not)?

2. Is the Baader Hyperion a good choice?

3. What will fitting the eyepiece to the camera do to the focal length of the eyepiece (should I go with another focal length)?

 

I know this is a lot and quite equipment specific, but hopefully someone has an opinion. :-) Thank you so much.

Mikkel

[Chinapig]

Hi Mikkel

I'm no expert in AP either, but from time to time I do use an Olympus OMD EM5 ii camera with my refractors.

My usual setup is a micro four-thirds to T2 adapter on the camera, fitted with either a 1.25" or 2" nosepiece to fit the focuser on the scope.  There seem to be at least two versions of M4/3 T adapter available and, as I understand it, which type you need will depend on the degree of back focus available on your scope.  There's an example here:

http://www.365astronomy.com/T-Ring-Micro-Four-Thirds-T2-Lens-Adapter-Ring-for-Micro-4-3-dSLR-Cameras-WITHOUT-EXTENSION.html

It's probly easiest to try the camera initially without an eyepiece - ie for normal prime-focus photography - but once you've got the M4/3 T adapter for your camera, then you could try eyepiece projection by simply connecting it to the Baader T2 eyepiece adapter fitted to your eyepiece.  Very occasionally I use that method for lunar and white-light solar shots, with a 24mm Hyperion - although I understand that the 21mm is a slightly better eypiece, but I can't remember why, sorry!  Fitting the camera won't change the focal length of your eyepiece, but the camera will obviously see a larger image with a shorter focal length eyepiece.

Hope that helps.

Cheers

Simon

 

[rotatux]

Hi, you should try prime focus AP first, with a T2 adapter (like the above one which I have the Baader-labelled one and recommend highly) and nose piece. I guess your current scope has 1.25" focuser not 2" so you will need a T2/1.25" nosepiece. Projection AP through an eyepiece is more targetted to smaller targets (such as planets) and more difficult IMO, but doable anyway.

With 900mm focal length, a MFT sensor already has a not so wide FoV of 1.10x0.83°, so I'm pretty convinced you actually don't want to do projection AP first. Since I image myself with a MFT sensor (Olympus E-PM1 before, E-PL6 now) you could have a look at my gallery and check what can be had with a short focal (130PDS = 650mm) and long focal (127MAK = 1500mm), while remembering your 900mm is about exactly between the two FoV-wise.

Finally a possible warning: many entry-level newton scopes have their focus "plane" not outside enough the OTA, barely enough for eyepieces and barlows but usually no more. Remember that for prime focus AP, you will bring the sensor to the focal plane with the focuser, not the reverse, so the focuser must rack inside enough. Given the MFT has ~20mm flange and the short T2 adapter is ~25mm long (from memory, I hesitate with 19mm), that's 45mm + optical length of the nosepiece that the focuser will have to compensate. Check this. A possibility to counteract this problem is to raise the primary mirror -- in a non destructive way (you will find some threads describing this), but then you will get some significant vignetting (this can be handled with flats).

[Mikkel]

Hi again thank you so much for your help. I've been doing a lot of reading since, trying to get my head around how this actually works and specifically with my telescope. I Will definitely have a go with prime focus before trying projection. As I understand some people use a Barlow or powermate to both counteract the back focus problem and to have a "medium" magnification. Any thoughts on that? 

 

And again thank you for your kind and thorough replies