Too Much Dew

[Meadehead]

I was out Saturday planning to do an all nighter with the Orionids but in the end I was defeated by dew and had to call it a night due to dew.

I found my eyepieces & filters all fogged up and the correcting plate on my telescope which made it impossible to see deep sky objects, I waited for Mars to rise to view it for the first time but it looked like just an orange fuzzy blurry ball.:(

This is my first dew experience and have seen dew heaters & dew shields and wondering if they really work and if this occurs often and how do I prevent my eyepieces and charts on the table from getting drenched? :shrug:

[ballaratdragons]

Yep, dew heaters really work!

I now go out in minus degree temps and image all night WITHOUT having to use the hair dryer! My optics stay crystal clear and dry whilst water is running off everything else.

Yes it can happen often. If your optics temp drops below ambient.

Picture a glass of cold drink. Where did all the condensation on the outside of the glass come from? Now imagine your optics being cooler than the surrounding air. Same thing.

Dew heatres don't get hot. They don't even get very warm. They just raise the temp of the optics a few degrees.

[Blue Skies]

Dew heaters are great! A dew shield will just slow down the inevitable (but their extra advantage is they also block out stray light from the side). Dew heaters just warm things up a tiny bit, just enough to keep the dew off, and they make a world of difference! The heat gets through very easily. I could never see how the heat could get past the plastic/metal cells that hold the optics but it does.

[leon]

Just to add my two bob's worth, dew heaters are the best invention since sliced bread.
I never had the opportunity to use then until about six months ago, and like Ken said earlier, we can, and do work in minus degrees temps all night without a single hitch, I now wouldn't work without them.

Leon

[Stephen65]

Dew heaters almost always work, the only time mine was defeated was observing in far Northern NSW in July - humid 20 degree days dropping very quickly to 5 degree nights. In Melbourne so far my dew heater has triumphed.

[Meadehead]

Thanks all, so it sounds like a dew heater would be a good investment.

How could I avoid dew or condensation on my eyepieces though?

[Zuts]

Dew heater straps come in all sizes, ranging from big enough for a C14, down to 5 inch straps for small refractors and even smaller for eyepieces and camera lenses.

Also once you finish with a particular eyepiece, put the caps back on and put it in your pocket or back in the case, if you leave it out it will dew up :)

paul

[ballaratdragons]

What's an 'eyepiece'?

:lol:

[Geoff45]

One of these things that Patrick Moore uses.

[Meadehead]

Ken, Its the thingymajig that plugged up the hole where your 'Toucam' now sits in :lol:

[night-vision]

I don't have a problem with dew at the moment, just cloud!:mad2:

I did manage to get out on Saturday night for a few hours, had my first dabble in some imaging with my Minolta DSLR .

unedited: http://farm3.static.flickr.com/2174/1775036195_ed98b5585c_o.jpg (http://farm3.static.flickr.com/2174/1775036195_ed98b5585c_o.jpg)

I think I need a focal reducer though.:doh:and more skills :)

[§AB]

^^ as a fellow Berwick resident, I share your rage at the cloud :P:(

[night-vision]

Hey there §AB,

Yeah it has been horrible,
I don't actually set up my gear here in Berwick, I have a mate in Garfield and another in Kooweerup on farms, I usually head out there to beat the bright lights which is good but it doesn't beat the cloud.

PS: I enjoy reading your Ob's reports:thumbsup:

[Meadehead]

Not bad picture Mick :thumbsup:

[Tamtarn]

Put the eyepiece in your pocket or back in the case, but I would leave the caps off other wise you will trap dampness inside on the lens.

After the nights use we leave our eyepieces on a table inside the house uncapped for several hours to dry out. If the dew is bad we leave them uncapped till the morning.

I have seen several eyepieces and filters ruined because they have been capped when damp. It is not worth the risk.

The best way to protect your most used charts is to laminate them.

David

[Meadehead]

Thanks for the advice David

[night-vision]

Cheers John



You have just reminded me that I've left mine in the car.. oops

[ballaratdragons]

You can also use the method used and suggested by Laurie (Rajah). He has a small heater in his EP case.

[Astro78]

If your on a budget (these branded heaters aren't cheap for what they are) - check out http://www.iceinspace.com.au/index.php?id=63,292,0,0,1,0

I haven't got pics but was able to easily make a dew heater from resistors and self adhesive Velcro. Cost less than $10. Worked a treat throughout winter!