WO Zenithstar 73

[Peter Reader]

Just picked up this Zenithstar 73 second hand as my first wide field refractor (FL=430mm) to use with my Canon 1000D and complement my SW 200PDS (FL=900mm with coma corrector/reducer).

I'm primarily into DSO imaging and due to funds it was important to me that I could share the remote PC (Melee Quieter 2) and guider (ZWO224MC on SW9x50 finderscope) between telescopes. 

So for anyone interested: the SkyWatcher finder bracket will just about fit in the William Optics handle (it looks a bit rubbish but is at least solid).

Pixel size of guide cam    3.75    um
Pixel size of main cam    5.71    um
Focal length guide scope    180    mm
Focal length main scope    430    mm
Resolution guide scope    4.3    arc-seconds/pixel
Resolution main scope    2.7    arc-seconds/pixel
Imaging / guiding ratio    1.6   

Sensor width guide cam    4.9    mm
Sensor width main cam    22.2    mm
FOV guide cam    94.2    arc-min
FOV main cam    178.6    arc-min
 

Question for experts: I have the Zenithstar 73 tube rings quite close together so the dew shield can retract and allow the scope to fit in the case. The tube rings therefore do not straddle the Declination axis - any issues with this? 

Edited May 22, 2022 by Peter Reader

[jacko61]

I wouldn't have thought not straddling the dec axis would be an issue so long as the set up is balanced. However, It's possible that with your tube rings so close together you may get some lateral flex of the main OTA. (if you hold a stick at both ends it stays where it is but move both hands to the middle and the ends will wobble all over the place).  I'd also be concerned about the flex between the handle and the guidescope mount - It's only locked with one screw so I reckon there'll be some movement there. 

FWIW, I bought a hard case for my set up so I can put it away with the reducer and guidescope still fitted and with the dewshield only partly retracted.  (since the pic was taken I've added a ZWO EAF focus motor and a Losmandy plate and now it doesn't fit the hard case so I'll be looking for an alternative.) 

Graeme

[Peter Reader]

Thanks for the info. How much for your hard case @jacko61 ? 😁

Edited May 25, 2022 by Peter Reader

[jacko61]

£70.

https://www.trifibre.co.uk/product/max520/

unless you're meaning the one I have - it'll be repurposed when I replace it. Sorry.

Graeme