How many clear nights in a year ?

[peterbolson]

I've had my telescope for a year now & have been trying to justify the expense of an upgrade. This set me thinking about just how often I would use use it. I know that the number of clear nights in the past year has been a lot less than I thought it would be before I actually started looking at the sky. Presumably many people keep records so I wondered what the figure would be. Fifty at best ? Perhaps even that is optimistic. The number of nights I've planned for and anticipated is certainly a lot more than that

Peter

[Double Kick Drum]

On count back this year, I think i've had six with the scope out and one session with just binoculars.

I tend to not bother with a fullish Moon though, so have probably turned down a couple of opportunities too.

[Craig20264]

I think if you get fifty nights it's worth the expense. I know guys who have spent a couple of grand on cricket equipment, and they play 20 games a year, and that's if the weathers good, a lot less if we have a bad summer.

If you can afford it, and you enjoy it, well there's no reason not to spend it.

We only pass this way once

[starnut]

How funny I have been doing this for February in south Hampshire just to see before spending out for my scope

Clear – very cold = 5

Clear – cold = 2

Clear then cloudy = 4

Cloudy = 12

Snow = 2

[David Smith]

I keep some stats on this. Over the last 5 years (2007 to 2011) I have recorded an average of 18 - 25% of the year has a clear night. Jan / Feb of 2012 has blown that away and had 40% clear nights so far!

[Capricorn]

Depends on how you count a clear night.

If clear Monday to Thursday they are of little use to me, I work and I need to get sleep for the next day`.

If it is clear at 2:00 AM but not 10:00-11:00 PM does that count. Would you see cloud at 11:00PM and wait up til 2:00 to see if it clears? In effect does a 2-3 hours clear spell say 2:00-5:00AM count as a clear night. You could observe if you were around.

So there are probably quite a few clear nights, or times during the night when observing could be done but circumstance prevents.

[Robd]

As a photographer I avoid any clear night with a fullish moon. In 2011 I got out on 21 nights.

With different gear to mine ( filters ) it is possible to shoot on full moon nights so this count could probaby be doubled.

There have also bee occasions when it does'nt clear until late, I am afraid that once I am settled in front of the fire I do not venture out. So a few more opportunities missed.

Rob

[dmahon]

This is, I suspect, where a permanent pier set up, even better an observatory, really helps. If you can set up and tear down in under 5 minutes, you are more likely to use your gear when you have a window of only a few hours or even if the weather looks like it might be changeable.

At the moment it takes me about half hour to set up, polar align and sync the GOTO, longer if there are any gremlins, and maybe ten minutes to pack away. This includes multiple 100 yard dashes carrying about 100kg equipment in total. So I tend not to bother unless the forecast says it is going to stay clear all evening and get rather upset when the predictions of the weathermen are completely useless only a few hours out (I forgive them if they get it wrong days in advance, but when they say it is currently clear and I can see through the window that it is actually cloudy and raining, I despair).

[David Smith]

When I record a clear night it means I cannot see any cloud. I do not exclude clear nights around the full moon but it is subject to my being able to see that it is clear (ie if the sky clears after I have gone to bed then it will not get recorded).

[pete_l]

Historically I have averaged 15 - 20 sessions per year. That's for a rig that I have to drag out, set up, (learn to use again ), and put away again afterwards. I tend to avoid evenings with a bright moon as well.

However, the Met Office(link) keep stats that are available to anyone for historical weather - including sunny/clear data by the hour. I snarf this on a regular basis and "pretty plot" it. Here's what the past 2 years looks like for my location in S.E. England

http://stargazerslounge.com/

[scogyrd]

I think I've had more clear nights this last week, without a full moon to ruin the views, than I did in the whole of last year.

[Peter Drew]

A better indication of telescope value might be the number of times a year you are able to use it at all, rather than for how long.

[UnderTheRain]

Got my first scope 6 weeks ago and it's been cloudy most nights. Worked a 10 hour shift yesterday got home shattered but the sky was so clear so I had to get my scope out spent 3-4 hours just slewing around randomly to see what I could see, got my first look at mars although the seeing was v poor but it was still great need many many more clear nights though :-)

Only the secondly clear night here in 6 weeks

[RikM]

Last year I got about 25 sessions with the imaging gear where it was clear for most of the night. With the Dob I used it much more but only got it in June. It is so quick to set up that even for half an hour it is worth it. Most weeks I get a chance to to get out once or twice at least.

[hes not well again]

Irecently read a book on astronomy from 1830 ish and the author claimed that on average about one hundred nights a year are clear. That seems a bit high to me. Where I am by Glasgow an average of one night a month of partial cloud seems about right with the rest horizon to horizon cloud cover for the last three months. The Oban weather station has recorded 139 days of consecutive rain!

[ollypenrice]

Where I live in SE France the professional observatory to our south has records going back to the thities. Dome opens 300 nights per year, stays open all night on 250 of those. That sounds aboout right for us, too. I'm totally wasted at the moment because last night was our 16th consecutive clear one. That is quite unusual. You expect a few more nights off than that in a new moon spell!

In Derbyshire I got literally a handful of really clear nights each year. I found it very depressing and am glad I moved.

Olly

[Shibby]

I've just looked back through my data and appear to have had ~15 imaging sessions in the last 12 months. Interesting to hear peoples' records of clear skies.

Dome opens 300 nights per year, stays open all night on 250 of those.

I used to like you Olly.

[Bart]

Most weeks I get a chance to to get out once or twice at least.

Wow! Rik, you must be a vampire, waiting all night to find a crack in the clouds, or it is something special where you live that lends itself to clear weaather?

Bart