Over the last year I have significantly updated my equipment. See here for details on the equipment used to take many of the images on this site.

Dave's Imaging Setup.

An overview of my imaging setup.  A Celestron CGE mount is the base on which its all built.  The main scope is a 10" f/4 newtonian with an oversized secondary mirror to provide better field illumination.  A Baader MPCC coma corrector reduces the serious coma which is inherent in fast reflectors.  A Celeston 80EDII "Onyx" refractor is also used heavily for imaging.  A 5" Maksutov Cassegrain is the main guide scope (shown in later images).

Having spent many happy years with my Celestron CG5 mount the time came to update this for something a bit more robust and precise.  Having examined a few options I finally settled on the Celestron CGE mount as the mount on which I would re-build my imaging rig.  As you can see in the photo above, i have removed the legs from the tripod so that the mount attaches directly to the conrete pier in my observatory.  The CGE has proved to be an excellent choice with low periodic error and extremely accurate gotos.  This makes the process of finding and framing faint fuzzies a real 'piece of cake'.

The choice of an f/4 reflector as the main imaging scope was based on some very impressive results I had seen with a similar setup.  The downside of a fast reflector is pretty serious coma towards the edge of the field of view.  Visually and without a coma corrector this is very noticeable.  However by introducing a coma corrector (such as Baader's MPCC) which I use greatly reduces this in the final image.  I am currently looking to get hold of a tel-vue paracorr corrector as this model is designed for f/4 scopes.  The other thing to consider with a fast refractor is collimation.  This must be perfect everytime.  Before each imaging session I make sure to spend 5 minutes checking the alignment of the optics to ensure optimum results.

The 80ED "Onyx" refractor is currently on loan to me from our local dealer "Astronomy & Space".  It really is a lovely little scope.  it provides lovely sharp views, free from any noticable abberations. At 480mm focal length, it provides nice wide angle views of nebulae and clusters which would otherwise be too big to fit into the field of view of the main scope.

Autoguiding.

For many years I used a modified webcam with great success.  The only slight downside of this was the need for several cables to make it all work.  Recently I have purchased a "Q-Guider" from CCD-Labs in the U.S.  This provides almost a one cable solution to autoguiding.

My Autoguiding Setup:  This consists of a 5" maksutov Cassegrain mounted along side the imaging scopes.  The camera is a "Q Guider" from CCD-Labs.  This camera has an inbuilt guider relay port which does away with the need to have a separate external relay box for making autoguiding corrections.  A single cable goes from the camera to the autoguide port on the mount and a single USB cable goes to the controlling PC. The Q-Guider is also very sensitive reacing 11th magnitude in 2 seconds easily.  This allows me to guide on very faint stars which are almost always in the field of view of the camera wherever it is pointed.  The camera works in conjunction with PHD guiding, which is supplied with the camera (can be downloaded for free).

The key to a good autoguiding setup is a sturdy mounting arrangment.  Here you can see my homebuild arrangement for this.  The mounting bracket stared life as a musical synthesiser stand which I cut up and modified.  It primarily consists of a rectangular box section firmly bolted to the main scopes mounting plate.  At either end is half of a commercial dovetail plate.  This arrangement allows me to mount a scope on either side of the main scope.  This means that balancing the scope is possible (would not be possible with a scope at just one side).  This arrangement is totally over-engineered on purpose.  Any flexure of this arrangement would result in poorly guided images.  I have certainly never had any such problem with this setup.

The Main Imaging Camera and Filters

For Imaging I use two cameras.  I am very lucky in that a many of my astro buddies also have some pretty decent cameras.  We like to swap and try out each other's gear from time to time.  So on occassion I have gotten to use an ST8-XME, and even a Luminera SkyYnx camera for planetary imaging.  Anyway my main CCD camera is an ATIK16HR monochrome CCD camera. I chose this camera for its high resolution (1392 x 1040) and reasonably sized, 6.45micron, pixels.  Being a monochrome camera it is very sensitive and definitely one of my better choices. I made a simple filter holder which enables me to mount filters on the inside of the main scope's tube.  This removes the need for removing the camera for changing colour filters.  The filters themselves are a 2" Astronomik Interference LRGB set.  These really are lovely filters and offer very good passband characteristics.  As my observatory is in an urban area an Astronomik CLS (minus city lights) filter comes in very handy too.  I do find than most nights this filter is really not necessary.

My other imaging camera is a modified Canon 300D.  This overs a nice wide field of view and single shot colour.  However of course being a commercial DSLR the effeciency of the chip is nowhere near as good as the ATIK16HR.  I have designed and built a stand alone elctronic shutter control for this to save all the hassle of using a manual cable release.  i could of course achieve the same thing by directly connecting to the observatory computer but the stand alone unit helps simplify all the cable coming from the observatory computer.

The ATIK 16HR Up close

Future plans

I am lucky to have acquired many of my 'objects of desire'.  However as you might expect I still have a few more planned.  I would certainly like to try my hand at imaging through a large aperture apochromatic refractor.  I hope to acquire one of these later in 2007.  At some point narrowband imaging is definitely on the cards.  So a set of high quality narrowband filters will have to be procured at some stage.  Other plans relate to some DIY projects such as a couple of light boxes for creating flats fields.  Currently I create flat fields by pointing the telescope at an illumated piece of whiteboard.  This is not ideal and also means moving the scope during an imaging session.  A light box (which mounts over the top end of the scope) will allow me to take flat fields witout miving the scope at all.  I still have quite a bit of work to do on my observatory including flooring and insulation which will happen this summer.  The roof rollers also need a bit of work as they are now getting quite sticky.

A robotic focusser is also on the drawing board at present this will allow far more repeatable and precise focussing.

....And Finally!

Finally I though you might like to see my backup autoguiding system. Yes it's my good friend and beloved pet Osker. Of course she will only guide on stars in 'Canis Major' and she can't take her eyes off the 'Cats Eye Nebula' or of course the 'Dog Star' Sirius :) She always manages to get caught up in the cables. I leave on single loose cable, Osker will find it.!!However a nights imaging session just wouldn't be the same without the trusty mutt.