dew on primary ?

[rory]

after letting the scope cool for 30 mins followed by no more than an hour observing i bought the scope back in on two counts. 1/ poor conditions due to the fires and fireworks ect and ,combined with seroius amounts of dew . 2/ the lazy susan id fitted was way to loose and needed tweaking.

so once in and finished thought id check collimation . the view when i looked through the collimation tool was unreal,a streaky blurry mess. took tool out and upon checking the mirror it was completely misted up. i wouldnt have expected that after an hour and a half outside max would you ?

ive had a few nights where dew was rife but it had never got down to the primary mirror before ?

im letting it dry out tonight and i'll check it in the morning,i just hope its only dew down there and not ash or fallout from a firework.

[Keiran]

Rory, you should be fine. Just let it dry out naturally. It does happen (obviously) excessive moisture in the air, sudden drop/increase i temp lots of reasons as to why. If you wanted to continue observing, I know you dont because of the conditions, but you could use a 12v hair dryer to create an air flow down the tube (not directly on the mirrors), that can some times help

Keiran

[rory]

thanks keiran. its already starting to receed ,but worried me as the dew seemed to show all the imperfections on the surface,dust ,streaks ect. must be very moist out there tonight.

[Moonshane]

did you say you'd brought it in? bringing a cold mirror into a warm house is a sure way to a dewed mirror in seconds. this normally happens at the end of the night so it's nothing to worry about and as suggested will be dried out in the morning. leave your scope close to horizontal if possible to stop drips and dust hitting the mirror.

[Keiran]

Yeah i can imagine Dont worry about all of that dust etc, it wont make any impression on your viewing. Dew always make it look worse than it is

Oh and as above, and leave the cap off, it will help it dry out and allow the moisture to escape.

Keiran

[rory]

did you say you'd brought it in? bringing a cold mirror into a warm house is a sure way to a dewed mirror in seconds. this normally happens at the end of the night so it's nothing to worry about and as suggested will be dried out in the morning. leave your scope close to horizontal if possible to stop drips and dust hitting the mirror.

will do, thanks chaps.

[crashtestdummy]

i had this big time a month back when bringinh my scope in after a cool hour outside and now i just leave the scope in the garage so its always cool as i was worried about condensation all the time from constant hot to cold.i also have some bags of silica which i hand in the scope tube while its in the garage to catch all the moisture

[rory]

i think ive realised the error of my ways. mirror looks okay.