New Forest Observatory ®

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 🙂

Tom How spent a night over the Bank Holiday weekend at the NFO where he had a good play with the mini-WASP array – I was attempting (half satisfactorily) to polar align the Hyperstar III in the south dome.  Meanwhile Tom in the North dome was collecting some quite nice Heart nebula data from Camera 1 of the two camera system.  This image shows about an hour’s worth of data collected using the Sky 90 with IDAS filter and an SXVF-M26C 10 Megapixel one-shot colour camera.  The camera has not yet been collimated which explains the star shape changes across the FOV.  However – the camera response is much as I have seen previously with the M25C (bigger pixels) and so it proves as I had anticipated, that I will not see any reduction in sensitivity with the smaller M26C pixels as I am working at a pretty short focal length.  So – a step up from 6 Megapixels to 10 Megapixels and then times 2 for two cameras – this mini-WASP array will be producing some amazing data when it is all tuned up.

So what more needs to be done before we can see the full power of the mini-WASP array?  Not a great deal really:

1)  Properly focus train and collimate both cameras.

2)  Align cameras for slight overlap so that I can take a 4 x 3.33 degree field of view in one go.

3)  Take some new flats with a properly collimated system.

4)  Focus train for the H-alpha, H-beta, SII and OIII filters.

And that should be  it for a while 🙂