Hello, and help? (a mistake regarding dew)

Rowlfie (Matt) · #1 14-06-2009, 01:17 PM

Hi IIS people, my name is Matt...

I recently purchased a 12" Skywatcher dob telescope. Its one of those collapsible things so the tube has an opening between the primary and secondary mirrors.

I was using it last night out in my backyard and ran into an issue with a lot of water forming...well over everything except the primary mirror. I persevered with this, not really knowing what to do about it in the short term..

So i do a bit of Google searching and to my horror i read that i should not pack my scope away after a lot of water has formed on the instrument.
Alas...this is exactly what i have done.

I've just unpacked it and had a look over the tube and mirrors and a heck of a lot of water has gone down the main tube part and onto the primary mirror. It looks all streaky and is still damp. so is the main tube

I am really unsure of what i should do about this, and hope that some of the more experienced members can help me outta this stuff up!

Should i be removing the primary mirror and cleaning it? Should i just let it dry or maybe apply some warmth near it like a hairdryer type of thing?

thanks,

dannat (Daniel) · #2 14-06-2009, 01:29 PM

I would let it warm first before pulling out the mirror, a hair dryer will be fine but keep the heat on low
once it warms & the water clears then look how the mirrors are looking

Rowlfie (Matt) · #3 14-06-2009, 01:40 PM

So its dryed up and doesn't appear to have left and streaking or dirt. Phew.
Guess i had better look into dew control, heaters maybe...

Thanks

rmcpb (Rob) · #4 14-06-2009, 04:31 PM

In future, I would bring it in, leave it open and on its side so the water simply runs off the mirror.

If possible, storing it in a non-heated room, like a shed, and allow it to warm up next day and dry out slowly is a great idea.

Starkler (Geoff) · #5 14-06-2009, 05:10 PM

Yep any time you take it in from the cold into a warmer place condensation will form. Try not to leave the scope pointing vertically and the condensation will run off.

M54 (Molly) · #6 14-06-2009, 07:15 PM

Hi Matt,
welcome to IIS.
You'll always find great advice here. There's plenty of people who know what their talking about. (But I'm not one of them)

Robh (Rob) · #7 14-06-2009, 08:05 PM

Quote:

Originally Posted by M54

Hi Matt,
welcome to IIS.
You'll always find great advice here. There's plenty of people who know what their talking about. (But I'm not one of them)

Sometimes, when we think we know what we're talking about, we realise we don't really know what we're talking about. By that time the horse has already bolted!

Regards, Rob

mozzie (Peter) · #8 14-06-2009, 08:06 PM

yep fust let it dry the next day i would put my scope in the sun for an hour or so to dry out welcome to winter cold nights but there worth the clear crisp seeing
mozzie

Blue Skies (Jacquie) · #9 14-06-2009, 10:45 PM

As long as you dry it out the next day it should be fine. Just leaving it open inside in a dry room for a couple of hours will be enough, you don't need to do anything special to it. Its when you leave it all packed up wet for days on end so mould can form that its bad. Do not ever wipe the mirrrors with a cloth! All you will do is put scratches in the coating, and that will be far worse than a water streak.

mswhin63 (Malcolm) · #10 15-06-2009, 09:52 AM

I usually find that if you have any moisture on most thing things and you have a refrigerated airconditioner, thurn it on and it usually removed moisture in the air helps with drying out.

Winter time though would be damn cold.

jjjnettie (Jeanette) · #11 15-06-2009, 10:05 AM

I always have a hairdryer plugged in next to the scope and use it to keep the dew under control during the night while observing/imaging.
When it's time to pack up, I wipe down the outside of the OTA with an old soft t-shirt then use the hair dryer to make sure it's completely dry inside and out, not forgetting the finderscope.

Rowlfie (Matt) · #12 15-06-2009, 02:11 PM

Thanks for the responses. I think i panicked prematurely, seeing the awful mess on the previously prefect mirror.

Seems to have dried up nicely!

It was a blow out seeing Jupiter for the first time, even through all that water on the eyepieces and mirror. Its my 3rd time out with the scope and the first few views were kind of a let down, me being inexperienced and not knowing where and what to look for.

Stars are cool and all but they look like dots, there is just more dots than when i look up without the telescope.

Very cool, could make out banding and even the little eliptic of the storm...

erick (Eric) · #13 15-06-2009, 02:20 PM

I was more interested in what you saw, rather than the minor matter of dewing up!

Be patient. Read a lot. Buy the magazines. That will point you in the direction of the wonders you can see with your scope.

erick (Eric) · #14 15-06-2009, 02:21 PM

See if you can find Saturn. At the moment that is an early evening target - before the dew will get you!

GrahamL · #15 15-06-2009, 07:20 PM

Hi ..To help out finding stuff do .. you could try one of these
http://www.backyard-astro.com/equipm...ad/telrad.html

My 12" primary also rarely dews up in our climate but condensation like mentioned above does form when brought back inside .. I find asside doing what you can to help it run off ..
"don't look down there until tommorow"" ..is a good policy .

enjoy your stay

rmcpb (Rob) · #16 18-06-2009, 03:33 PM

If you have to bring it in to a heated area. Seal it up so the air inside cannot get to the mirror. When the packet of cold outside air that is now trapped warms up its relative humidity will drop like a stone and keep the mirror dry unless it already is dew affected.

However, don't forget to open it up when its warm so it can really dry out.

Jen · #17 19-06-2009, 12:23 AM

Quote:

Originally Posted by Robh

Sometimes, when we think we know what we're talking about, we realise we don't really know what we're talking about. By that time the horse has already bolted!

Regards, Rob

to IIS Matt