Zwo 224 or 290MC?

[BlueAstra]

I bit of quick advice required. I looking at a Zwo 224MC or 290MC camera for planetary imaging only with my Celestron 9.25" SCT, and perhaps an ADC. Any major differences between these two, any preference, or should I be looking at something else? Any comments appreciated.

 

Graham

[Demonperformer]

The 224 will give you a fov of 5.3'*7.1' and a resolution of 0.33"/px. The 290 will give you a fov of 4.6'*8.2' and a resolution of 0.25"/px.

Although the fov is great for planetary, I believe the accepted wisdom is that you should aim for a resolution of between 2 & 2.5"/px. Quite what the effect of such a difference will be, I am unsure, but others will no doubt be able to advise.

[Owmuchonomy]

The 224 is a better match to your 9.25" SCT if you use a 2x barlow or powermate.  You could use the 290 with your scope but to optimise it you would need a 1.5x barlow, not something easily available.  I have used the 290MC native with my 9.25" and it delivers stunning lunar images using an IR pass filter.  From memory the near infra red sensitivity of the 290 is the best of all the ZWO cameras.  Unfortunately, the planets are poorly placed for imaging for a few years so consider carefully your decision to go that route.  I will be getting much more use out of my ZWO ASI 174 mono over the next few years on the sun and Moon.

The pixel scales quoted in the post above apply to DSO imaging.  For planetary, a good rule of thumb is an f/ of 4 to 5x your pixel size hence my advice.