Wondering about camera lenses for Astrophotography

[mikey2000]

So, a few years back, I got my first telescope and immediately starting wondering how to attach my flashy camera to it.  This process led to the ultimate purchase of the ZWO AS1600 mono camera and filter set for my EQ6R guided mount.

 

All very nice and i'm definitely happy with the results.   

 

I sometimes wish for a wider view though....  My 150PDS is 750mm focal length and there is no way I'll fit a Heart Nebula, or Rosette, Andromeda Galaxy

 

So, I am looking at my flashy DSLR camera lenses and wondering how I can attach them to my astro camera with the EFW.   It seems ZWO sell adapters for Canon and Nikon lenses that allow for the EFW and also for Sony E and Micro 4/3 but without the filter wheel.  (Oh dear - I don't want mono unfiltered data...)

 

The catch is that my lenses are all Sony A mount (ie, the Minolta AF mount).  I have a very nice SAL70-400Gmk2 that cost me more than I dare admit and it is wonderfully good as a photographic lens.   I wonder how I could attach it to my astro camera.   I'm half thinking of buying an dead A-mount camera and the Canon ZWO+EFW adapter and making a DIY modded adapter.

 

But I'm wondering if it is worth the effort...  Will a photographic lens be any good compared with a 150PDS?  I'll inevitably be disappointed by the light gathering  - the lens is F5.6 at the 400mm end and only therefore 71mm wide (comapred to 150mm on my scope).   Will I be disappointed with the sharpness (I could test this myself by taking a star pic with my normal DSLR, I suppose)?

 

Or should I just buy another telescope with a wider view?

 

All advice gratefully received!

[happy-kat]

Just to wet the appetite the are some stunning images taken using the samyang 135mm f2 lens.

Why not use one of the image calculators to see how the DSO you are thinking of fit with your mono camera and that 400GM mk2 lens to see if it's what you are after.

Just thoughts.