It is the first clear day in ages - makes a great change from the dull, dark, grey, completely overcast days we have been experiencing for quite a while now.  This is the view towards the West from the New Forest Observatory.  You can see a prime example of the wooden optical obstacle course I have to negotiate on my imaging sessions sitting right behind the observatory.

Last night there were some breaks in the cloud and it was also unusually mild.  So I took the 40D outside on the tripod (I should have taken the TT320 as well but I wasn’t thinking straight yesterday for reasons that will become clear on the 23rd December 2008 - come back to the NFO then and I took some frames of the dome and Orion.  ISO 800, 10-second exposures, 28mm focal length, f#5.6, about 15 stacked frames.  As I did a manual 2-star lock on the stars when stacking, the dome (and tree behind it) are blurred - but what this image does show is the nicely Sodium illuminated dome courtesy of about half a dozen close-by street lights!!  Needless to say lights stay on blazing away all through the night when the only thing they are doing is showing the way home to the foxes.

I have security alarms, and a fire extinguisher handy for the observatory - but it took a recent catastrophic failure of a PSU to make me think about putting a smoke alarm in there!  Fortunately I had two battery operated smoke alarms in the loft (builders put mains operated alarms in the house when they did some work).  So now there’s an added bit of protection for the observatory.  I would strongly recommend you do the same if you have your observatory within earshot as there have been several cases of fires going unnoticed with the obvious consequences.

Have you ever had the problem where the time indicated on one of your clocks (including your computer’s clock) is different to another one?  Well, I have and it can certainly cause headaches when trying to analyse the large amounts of data that we generate from our images. 

I now have one of those “radio-controlled” clocks that gives me the precise time via an atomic clock in the UK.  The clock broadcast signal is controlled and monitored by the National Physics Laboratory in Teddingtion and the transmitter was moved to Anthorn in 2003 - although everyone still refers to the atomic clock as “The Rugby Transmitter”.

So now the observatory computer is always giving me the correct time for the FITS data files and other astronomical programs that I might be running as I always “synch” it to my local atomic clock before each imaging session.

As I am located in the New Forest, you can imagine that for some months of the year, particularly from late September until late November, condensation is a major problem in the dome. 

I have always used a product called “Water Eaters” from Lakeland Plastics [I prefer the name "Water Snake" but I guess the marketing people at Lakeland didn't] around the gap where the dome rotates.  This product is basically a sausage-shaped piece of fabric filled with some water absorbing substance [possibly silica-gel]. 

I always place these in the gap around the dome edge [on the inside of the dome] after an imaging session and they keep the ingress of water vapour right down.  Unfortunately, on their own they are still not enough! 

I had a problem with the Hyperstar a couple of years back where halos started appearing around bright stars after about half an hour or so of imaging.  At first I thought this was atmospheric water vapour.  After quite a bit of investigation I found out it was actually water vapour in the Hyperstar itself - not good! 

I got rid of the trapped water vapour by placing the Hyperstar in an oven at 40C for about an hour, but I clearly needed to also do something about protecting the observatory. 

To this end I bought a dehumidifier which now runs full-time in the dome.  I typically need to empty the water container every three days [roughly a gallon I suspect] throughout the year. 

I also have a thermostatically controlled greenhouse heater in the dome which is used to keep the dome temperature a few degrees above freezing during the winter months.

So far, these precautions seem to be working - I’ll find out this coming winter 

Have you had similar problems?  If so, how have you deal with them.  Drop me a line and let me know.

We seem to have more than our fair share of power cuts in Brockenhurst and this has resulted in damage to both my computer and to the Celestron motor drive boards, both of which are very unpleasant experiences as you can imagine. 

I now use the Celestron Power Tank to power the Nexstar 11 GPS scope, basically a 12 volt rechargeable battery, and this isolates the scope entirely from the mains.  For the computer I now use an uniterruptible power supply [UPS] which is again based on a rechargeable battery which in turn powers an inverter. 

Finally, as I am also worried about glitches down the mains as well as the power cuts, I use Belkin “power surge” extension sockets which are designed to take any damaging spikes out of the mains supply. 

Touch wood - so far things seem to be working o.k.

I’d be interested to know if any one else suffers from similar problems and how you have dealt with it. Drop me a line and let me know.

Finally!  I have managed to eradicate the one minus point of having the Nexstar and motor drives in the dome!

I upgraded the motor drives from version 30.30 to version 40.40 (download available from the Celestron site).  Amongst the many benefits of the upgrade was that the telescope tracking is now entirely silent - HOORAY!