Crendon Observatory

Our September speaker was Gordon Rogers who gave us a talk entitled "The Crendon Observatory".


Crendon Observatory began life in the mind of one Gordon Rogers when one night he was looking through his 3" refracting telescope and saw a strange event on the Moon's surface. It was around 10pm in June 1994 when he saw dark smudges that appeared a milk-chocolate colour fading into white clouds. At first he thought it was just condensation on his telescope's optics but on checking this, he found that the mysterious apparition persisted. Just to make sure he was not seeing things he asked his wife and neighbours to look – yes, there was something there.

He decided it was time to ask the experts and so 14 'phone calls later he had managed to contact a lunar astronomer in Hawaii who said he would take a look that night. However, Gordon's luck was against him as that night was one of the rare occasions when the observatory was covered in cloud and so no observations were possible. From that day onwards Gordon was determined to update his equipment so that he would not be caught out again. So, he bought himself an 8" Celestron telescope and began taking many photos, including some of Comet Hyakutake. The only problem was that every time he wanted to observe or photograph an object he had to carefully set the telescope up on his terrace, which could take some time. His next step was therefore to house a new 16" Meade telescope in a garden shed with a roof that rolled off. However, his view was blocked by mature trees on three sides, and closing the roof meant disturbing the focus and synchronisation of the telescope.

He felt it was time to think about investing in a proper dome for his equipment. He wanted a clear view, which meant the observatory would have to be built above ground and he wanted it directly accessible from his house. As his house was thatched and already had several extensions there was only one place left. Unfortunately the plot of ground was owned by his neighbour and he knew already from previous experience that it would be difficult to build on. One thing on his side was that his son, Chris, was a builder and he was between jobs.

Work began by getting consultants to take sample bores so that contractors could design appropriate footings. The construction needed three reinforced piles sunk to a depth of eight metres. All this groundwork took 2 months to complete. Then the concrete pier to support the telescope had to be built. This was five and a half metres high and three-quarters of a metre diameter and was ingeniously made using a ribbed sewer pipe into which concrete was poured. This had to be done in stages to ensure that none of the concrete would burst the bottom of the pipe.


Including pier construction time, it took another three months to reach a stage where the building was ready to receive its roof – a steel Ash dome shipped all the way from Illinois. It turned up right on time and resembled some grown-up Meccano kit complete with a 76-page manual! But Gordon and his crew did not need to worry as it had been test-assembled in the factory and came with a helpful manual. The only anxious moment came when the shutter was being installed in place one windy and rainy day. A sudden gust of wind span the shutter like a top on the end of the crane's cable. But the crane's driver came to the rescue lifting it well away from the building until the wind had died down.

On 3 March 2001 the Observatory was officially opened in the presence of Sir Patrick Moore who featured it in a Sky at Night TV programme. If you get a chance, take a look at some of Gordon's pictures on his website: