Advice. It’s cold and wet

[IvorHogseye]

First proper nights observing in 12 years. Everything was perfect. New scope. New decking. Working through the nights best. Absolutely loving it. I’m wearing so many layers I can stay out all night. However.  First time SCT, it’s frozen up and I can’t see anything. What would you advise?  All my kit is now in the dining room. There’s no way im switching the heating on. I am happy to buy a few shield or whatever maybe make one?  Im guessing lots of you have had a similar night. Love it

[NGC 1502]

In damp cold conditions your best plan is to put measures in place before dew forms on the optics, not after.

You could make a dew shield from camping mat foam. Don’t make it too short, at least 2x the aperture. Secure with velcro. Perhaps a low heat dew band around the tube, level with the front corrector plate.  If (or rather when) dew does form use a 12v dew gun very carefully.  Check what’s available from our sponsors, First Light Optics.

Don’t be tempted to wipe dew from optical surfaces, especially outside in the dark, it’s so very easy to cause scratches.

Maybe do an online search, see what others have done.

Good luck!

Edit-  click on the FLO banner at the top.  Do a search “dew prevention” lots of equipment available!

Edited November 4, 2022 by NGC 1502
Extra info

[Cosmic Geoff]

A dew shield is an essential accessory for a SCT, not an optional extra.  A dew heater may be additionally needed in severe cases.  (I don't use dew heaters myself).  I have recently learned that Celestron supply a heater ring that replaces the corrector plate retaining ring and gives a neater solution than using a heater band.

[Neil H]

Hi I have a 180 MAK I use a dew shield and then a dew strap around that and not had a dew problem , I even made a small dew shield for the spotter scope ,FLO do a heated dew shield it fit most telescopes 

[Elp]

If it is a Celestron you have it's dew heater ring works very well. Pair it with a dew shield and you're good to go. Alternatively you could probably source a long length dew heater band to wrap around the front of the OTA.

[IvorHogseye]

Thanks everyone. That’s some excellent help. Yes it’s a celestron evo 8. I’ll make a dew shield and will have a look at the fancy dew heater. 
All the best 

Edited November 6, 2022 by IvorHogseye

[Nyctimene]

5 hours ago, IvorHogseye said:

I’ll make a dew shield

Don't forget the dew shield for the finder, as mentioned above (unheated, aperture 2x = length). I've even made dew shields for the RDF's of two scopes. If finder and RDF both are dewed up, you are out of business, except for moon and planets.

Stephan