As I sit here with a gale roaring outside and the rain pelting down I wonder if I will ever see a clear sky again – and this got me thinking about how I will run the mini-WASP array.
It was always my original intention that the mini-WASP array would be a “parallel imager” – that is each scope and camera would image the same object so that the total imaging time would be effectively the time you image that evening multiplied by the number of imaging cameras. I then got field of view fever and thought I’d rather have the cameras having an overlapping field of view (along one edge) so that I can form a mosaic in just one imaging session. The main negative thing about this approach is that by overlapping images you are effectively throwing away the pixels in the overlap region of one camera – with my 10 Megapixel SXVR-M26C cameras this is likely to amount to 1 Megapixel – almost the size of my first imaging camera!! This is not too clever. You also don’t get the “time gain” if you work this way, and seeing the very few good days we’ve had for imaging these last few months I am beginning to think that time gain is much more important than field of view gain. There’s also another reason why it might be a good idea to image just one object with multiple cameras. At present I have two scopes and imaging cameras – when it comes to adding the 3rd scope and camera it would be difficult to bolt its field of view onto the other 2 cameras – but of course it is no problem at all to use the third scope to once again image the same object as the other 2 scopes.
So – the way my thinking is going at present is that I will double up my effective imaging time on the single camera/scope field of view of 3.33 x 2.22 degrees, rather than sacrifice the imaging time for a massive 4 x 3.33 degree field of view. The full 4 camera mini-WASP array would of course offer the possibility of a massive 6 x 4 degree field of view at a very respectable sampling of 3 arcseconds per pixel. When I finally get to fitting all 4 imagers to the mini-WASP I might just possibly use it in the large field of view mode to capture those few very big objects (or groups of objects) that require it – it really is very tempting to play with a 6 x 4 degree high resolution deep-sky imager 🙂