ZWO OAG to SW 72mm Refractor

[Rigel]

Hi,

Can anyone provide some much-needed assistance.?

I'm (reluctantly) getting into imaging because I want to do simple spectroscopy with my Star Analyser 100 diffraction grating. I have a (new) ZWO OAG and a Skywatcher 72 refractor. Unfortunately, I can't fathom out the connectivity between the telescope and the OAG. The main camera side is obvious, but I can't see how the female thread on the drawtube of the SW 72 is the be linked to the OAG. Any thoughts?

Best regards,

Rigel, Guildford, Surrey

[Merlin66]

Can’t  help with the fitment of the OAG, but I would question why you think it necessary if you are going to use a SA100 grating?

Normally the grating would be mounted in the 1.25” camera nosepiece. (Which camera do you intend to use?)

With an EQ mount the non-guided tracking accuracy is probably good enough to get you started.

 

[Rigel]

Merlin66, Yes, of course you're right - I have the camera adaptor and nosepiece and that setup is fine. However, I want to experiement on some fainter, diffuse targets - inc comets. I know that a spectroscope with a slit rather than an SA 100 would be preferred for diffuse objects, but I can't afford one. The other reason for using an OAG is that I want to give simple, deep-sky, imaging a try - in particular I want to see how deep I can get with a small refractor (72mm) and a DSLR camera. 

Thanks for you comments!

Rigel.

[Rigel]

Can anyone on the Forum tell me how I connect the ZWO OAG to my Skywatcher 72mm refractor? Any help would be much appreciated.

Rigel.

[-Joe_]

Here how I connected mine:

Telescope -> 2” nosepiece -> 21 & 16mm extenders -> adapter thread -> oag

took me a while to figure out the adapter thread - was attached to something else.

here’s a photo, not sure if this is the optimal way...

[-Joe_]

Sorry, just like my astrophotography, those are slightly out of focus...

[-Joe_]

Just checked, and zwo call it an m48-m42 adapter, came with my zwo asi1600...

[Rigel]

Joe,

Many thanks for taking the time to reply. That helps a lot - particularly the image.

I'll get myself an adapter.

Malcolm.

[-Joe_]

I find this page useful for figuring out the various adapters:

 

https://astronomy-imaging-camera.com/tutorials/best-back-focus-length-solutions-55mm.html