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Condensation on underside of C8 glass
Posted: Wed Sep 13, 2023 2:41 pm
by gebbesup
I have a nexstar SCT 8" , I've had a lot of problems with condensation and bought the entender gaurd. Its given me some positive results but think I need to purchase a heater.
How ever even after a session there seems to be clouding on the underside of the glass on maybe about 25%, I feel it is effecting my ability to focus correctly. I've had much clearer images before this appeared.
Does anyone know what it is, what causes it and how to fix it?
Thanks
Re: Condensation on underside of C8 glass
Posted: Thu Sep 14, 2023 7:27 am
by Graeme1858
gebbesup wrote: ↑Wed Sep 13, 2023 2:41 pm
I have a nexstar SCT 8" , I've had a lot of problems with condensation and bought the entender gaurd. Its given me some positive results but think I need to purchase a heater.
I used to have similar problems with my 9.25
SCT.
What do you do with your 8" at the end of the session? In order to dry out the condensation on the inside of the tube you need to bring it indoors and leave it on its side with the Visual Back removed till morning.
You can get heated dew shields and you can also fit a heated dew ring. Fitting a heated dew ring requires removal of the ring that holds the corrector glass in place, so you need to be a bit engineering competent to fit one!
Let us know how you get on.
Graeme
Re: Condensation on underside of C8 glass
Posted: Thu Sep 14, 2023 8:58 am
by gebbesup
Graeme1858 wrote: ↑Thu Sep 14, 2023 7:27 am
gebbesup wrote: ↑Wed Sep 13, 2023 2:41 pm
I have a nexstar SCT 8" , I've had a lot of problems with condensation and bought the entender gaurd. Its given me some positive results but think I need to purchase a heater.
I used to have similar problems with my 9.25
SCT.
What do you do with your 8" at the end of the session? In order to dry out the condensation on the inside of the tube you need to bring it indoors and leave it on its side with the Visual Back removed till morning.
You can get heated dew shields and you can also fit a heated dew ring. Fitting a heated dew ring requires removal of the ring that holds the corrector glass in place, so you need to be a bit engineering competent to fit one!
Let us know how you get on.
Graeme
Thanks Graeme
I seen a few, I'm handy enough I think the heater ring is the way to go for me, the dew shield works well, but I end up with condensation eventually, here is a photo before without any dew mitigation, I'd get no time at all off my scope before it clouded up. I keep my scope inside I don't do anything in particular. I've removed the back today and will see if that helps clear it up.
Re: Condensation on underside of C8 glass
Posted: Thu Sep 14, 2023 3:50 pm
by Graeme1858
Have you still got the big bag of desiccant that comes with the Telescope? I used to put mine in the visual back hole till morning!
Then in the morning, when it's dry, put the visual back on again and it should stay dry.
Graeme
Re: Condensation on underside of C8 glass
Posted: Thu Sep 14, 2023 9:00 pm
by Bigzmey
I do the same as Graeme. Bring the scope in, remove diagonal and let it sit until condensate evaporates. Lately I started using insulated jacket for the scope body and insulated dew shield. This helps with both dewing and scope acclimation. In the pic below on the right is my 9.25" ready for action
Re: Condensation on underside of C8 glass
Posted: Mon Sep 18, 2023 12:19 pm
by gebbesup
no improvement I think its just dirt thats collected on the back over the years. my images are not too bad, its more annoying i see it there. might give cleaning a go at some point.
Thanks for the tips and good call on the desiccant I'll try get my hands on some.
