The scope comes with a CG5 Advanced Series mount.  When I purchased the scope, I had serious reservations about this mount, particularly after reading a review in Sky and Telescope (Aug 2005).  In his article the reviewer indicates that the mount is not capable of being autoguided.  I felt that the mount itself would be a stopgap which I would eventually have to sell on when I could afford a better mount like the Losmandy G11 or Celestron CGE mount.  Boy was I wrong, the mount has exceeded all of my expectations and proved wholly adequate as a platform for my astro imaging.  That being said its important to remember that this is a budget mount and does have limitations.  The main issue I have is backlash (slop) in the declination axis.  This has been problematic sometimes, however since my setup is not permanent and I set up each session, less than perfect polar alignment means that

The guidescope shown adjacent is a 127mm Maksutov Cassegrain by Skywatcher.  It has a focal lenght of 1500mm.  In itself this makes for a lovely imaging scope however I have yet to exploit its capabilities in that regard and for the moment it serves an excellent guidescope for the SCT.  Its probably a little overkill to use such a decent scope for autoguiding but it makes no sense to buy another scope when I have this one.

On other occassions I mount a Celestron 80ED refractor where the 127mm Mak is shown.  The C80ED is a delightful little scope and particularly good value for money.  It is a semi-apo (ED doublet) with a focal lenght of 600mm.  This makes it ideal for wide angle imaging of nebulae and larger clusters.

In order to achieve decent guiding the guidescope must be fixed TOTALLY rigidly to the main scope.  Initally I used a camera mounting bracket which proved to be totally inadequate.  I could only move the guidescope in one axis (left right) and flexure was a big problem.  Since taking delivery of the losmandy gear all of those problems evaporated.  I can now move the scope in any direction easily by adjusting the six thumbwheels and flexure is non-existant.  To anyone beginning astrophotography, I urge you to consider investing in a decent mounting arrangement for you guidescope.  Failure to do so will result in endless frustration and poorly guided shots.  Don't think that some flimsy arrangement of nuts and bolts will do, it WILL NOT work.

This was the single biggest challenge I faced when putting the rig together.  Initial tests showed that I could acheive around 2 minutes unguided exposure with the CG5 AS mount.  Thats a pretty good result for a budget mount.  However this is not consistently repeatable (maybe works 2 in 5 times).  It became clear that guiding was going to be necessary.  My good friend Jed Glover, gave me a 'Celestron radial guider' which I could use along with my Meade 12.5mm illuminated reticle eyepeice for manual guiding.  I was pleased with my initial efforts however it was patently clear to me that manual guiding could still be a hit-and-miss affair and was definitely a right pain in the neck!!  I was going to have to autoguide the only question was how.

From some research I arrived at two options.

Having been given a loan of an SBIG ST4, it was clear that this would work well with my setup.  The only drawback was cost.  I already had a webcam so I decided to pursue this and see if I could do autoguiding "on the cheap".  The results were very satisfying and is worthy of an article in its own right.

Basically the autoguiding setup works as follows.  The camera is repeatedly taking exposures of the field of view of the guidescope (typically 1-3 seconds long).  The camera send its images to the laptop where they are received by the free autoguiding software (Guide Dog v1.0.6 by Steve Barkes).  The software then compares a stars position in the frame to it's last known position and sends corrections to the mount to counter the drift).  Simply in theory but it does take a bit of practice to get right.  Interestingly the laptop I use is just an old IBM Thinkpad (233Mhz, 32MB RAM) but it works very well for autoguiding.

My camera is a Canon 300D digital SLR.  At the time I purchased it, I was looking for a decent camera for regular photography which would also be useful for astro-imaging.  The 300D (BTW now superceded by the 350D) again outperformed my expectations no-end!  The camera has a 6 megapixel CMOS sensor (22 x 15mm).  My first shots with the camera showed that this was going to be an extremely capable astro imager.  Best results are acheived by taking several exposures of the same target and averaging these afterwards in software.  This has the effect of bumping up the signal/noise ratio resulting in sharper and less grainy images.  After using the camera for a while I came upon probably its major limitation.  Due to the UV/IR cut filter built in just above the sensor blocking some important wavelenghts of light, the camera is not as sensitive to astro targets as it might be.  To correct this I surgically removed the filter and replaced it with clear glass.  Further details can be found here.

I mentioned earlier some of the woes which image shift causes during astroimaging.  However achieving critical focus in the first place can be a daunting task.  Focussing by eye through the viewfinder of the camera is just not good enough.  You may get lucky but you really dont want to be relying on luck.  A repeatable method which can quantify focus numerically and allow you to acheive the best possible focus is required.  The solution I chose was a piece of software called DSLR focus.  This works by measuring the width and height of a star in a short exposure and allowing you to correct the focus until the star image is as small as possible.  I found this method to be highly effective at achieving the very best focus.  This software also allows an automated sequence of shots to be taken, thus allowing for a more 'hands off' approach.

Oh that dreaded subject!! How I long for pristine inky black skies, so many others seem to take for granted.  I'm located in suburban, Dublin, Ireland.  For those outside Ireland, Dublin is a major city with over 1 million people living there.  Though I live about 4 miles from the city center, I'm luckier than some as I live very close to the coast.  Light pollution is always evident but not nearly as bad as other cities I have visited.  On a decent night the milky way is easily seen overhead.  However on a moist night the sky glows bright orange and presents major difficulties.

Most of my astro-imaging is taken through a 1.25" Parks Optical Broadband LPR Filter.  I bought this a couple of years back and its proven very useful.  Its performance offers a decent ratio of dimming light pollution to dimming astro objects, much better than other general LPRs, I have seen.  This works well for imaging nebulae but galaxies present a different problem.  LPRs dim light from galaxies appreciably meaning much longer exposures are required to get decent results.  This is a problem I have been wrestling with for sometime and have not yet come up with a satisfactory solution. I use a baader 1.25" UV/IR now that the stock UV/IR has been removed from my imaging camera.

Another problem I have is a busy commuter train line running alongside my house.  As trains pass the ground shakes noticeably.  I have found however that as long as the gear is well secured and everything is locked down, the couple of seconds it takes a train to pass doesnt affect the overall image quality too much.  In any case the trains stop running shortly after midnight.