Clear Night totals 1978-present
The weather in the UK plays a big part in an observers attempts to compile a detailed light curve. Very rarely does Birmingham experience more than 120 clear and partially clear nights in any one year. For continuity, advantage has to be taken of partially clear skies and even gaps and holes in clouds. Here is shown a graphical display of numbers of clear/partially clear skies since 1978. Clear nights are defined as 50% or less cloud. Partially clear is 50% or more cloud, including breaks or holes in cloud. 2002 has been the worst since my records began, with a miserable total of just 69 clear and partially clear nights available.
Observable nights in 2020
My Coldest Night...
The Winter of 1981-1982 was the coldest I can remember, certainly from the aspect of observing at the telescope. Water pipes burst, lakes froze over and telescopes ceased to function properly.
Although a temperature of -19c had been recorded in mid-December 1981, the thermometer reached a new low on the night of January 13th 1982. Here is a snippet from my observing log...
Jan 13th, 1982
"...sky superbly clear. Began observing at 18.30UT with the temperature down to -18c already! Soon reaching mag. 14.5 with the 10 inch. Right eye 'stuck' to eyepiece whilst observing SS Aur - very painful. Conditions deteriorating by 19.30UT. Both primary and secondary mirrors freezing over at 19.40UT. Finder-scope useless. Closed observatory at 19.45UT with temperature down to -21c. Dense freezing fog by 20.15UT."
Local (Kingstanding, B'ham) Day/Night temperature profiles from Dec 01 1981 to Feb 28 1982