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Walking on the Moon

Imaging Resolution, Software Binning & Camera Choice


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I wonder whether anyone can help point me in the right direction or offer a bit of clarification please ?

Scenario is that the wife and I have been carefully reading up and researching how we might take our first steps into the imaging arena. Of the scopes we own, one stands out for a multitude of reasons as being the one we should focus on to begin with (and for quite a while I'd wager). And that's our Evostar ED80 Pro. 

I am aware that a CCD or CMOS camera has to deliver an appropriate imaging resolution or arc seconds per pixel given the selected scope, use of a Reducer and seeing conditions. 

I've been having a play with the Resolution / CCD suitability tool available on Astronomy Tools and things look positive for one of the combinations we are thinking of using. 

As mentioned earlier, having taken a lot of information and advice on board, we are going to have our first crack at imaging with our Evostar ED80 DS Pro. We will use the 0.85 Reducer we have too and use our AdvancedVX Mount with either an OAG or some form of Guide Scope set up. 

(Our other scope will be a tad unwieldy for us as beginners as, even using its dedicated Reducer, our 8" EdgeHD would need precise guiding at a focal length of 1,442mm).

Attaching a ZWO ASI1600MM Cool to the Evostar and its Reducer would appear to give not only a decent wide field of view, but also an arc seconds per pixel return that hits the "green section" with OK seeing parameters entered. 

So happy days so far. 

Now, perhaps I shouldn't really be doing this, but I couldn't help throwing my mind forward, to a distant day when we've got to grips with guiding and all the associated factors associated with imaging with the Refractor. 

The question formed in my mind "could this camera yield anything if we strapped it to the back of the 8" EdgeHD with its 0.7 Reducer ?".

No doubt another dedicated camera would be better with the EdgeHD and Reducer, but I found that I can still hit the "green segment" of the arc seconds per pixel ratios if the ASI1600MM is binned at 2x2. 

However, as it's a CMOS sensor the ASI1600MM can't be hardware binned as the pixels can't be read column by column or row by row. As they are read individually they can only be binned by software manipulation. 

Although I know the best answer would be to purchase a dedicated camera for the EdgeHD when we felt ready to try that, I was wondering whether we could assess whether we could guide the 1,442 FL sufficiently well by using the camera from the Evostar. 

So question 1 is:
Would the use of software binning make the ASI1600MM a suitable camera for us to test out our abilities with the EdgeHD ? Or does software binning not deliver the same end result as hardware binning ?

This then led to question 2 which is:
Is there an alternative camera to the ASI1600MM Cool that we should consider purchasing for the Evostar that could also work with the EdgeHD? Or will that result in compromise and a dedicated camera for each scope really is the only answer ?

Thanks in advance 


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Asi 1600 on the 80ed seems a good choice to me. You should be able to get lots of great images with this. This is a user friendly combo, that you can use to learn AP, without having a too steep learning curve.

As for guiding, you don't really need oag with this combo, and oag also seems trickier to get working than piggy back. On the other hand, your EdgeHD will benefit greatly from off axis guiding (long fl, risk for flexure, etc), so if you only want one guiding setup, oag may be your best choice.

But you should ask yourself, what you want to image with the EdgeHD. If you want to do planetary with this scope, then a one shot colour camera may be better than a mono cam.

Personally, I would use the 80ED / ASI 1600 for imaging, with piggy back guiding, and use the EdgeHD for visual.

But that's just me. :icon_biggrin:

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Thanks Wim. That could be the way we end up finally... We're conscious that "one step at a time. And make them small steps at walking pace" is by far and away the most sensible approach. I have a tendency to go head long recklessly normally !! So I'm surprising myself and Susie at the moment !! :biggrin:

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