Out right now have a question about Dew.

[StarDuke82]

It’s the first night in almost 4 days that I have been able to get my scope out however it’s very humid and I have dew that’s formed on my corrector plate it’s only 12 am still plenty of stuff to look at but my evening is ruined at the moment. I know it’s a horrible idea can I use of my microfiber lens cleaning clothes to wipe the condensation off my lens if I’m through in drying and removing the condensation and then use the make shift dew shield I quickly threw together out of some cardboard and extra insulating foam I have laying around or should I just pack it all in and head back home?  I just threw the scope in hibernate mode because I am unsure what to do I don’t want to streak up my corrector but I just got my first glimse of a globular cluster before I realized how much dew was accumulating so despite the moisture skies are pretty clear tonight. If I pack it in I will be sure to not put the lens cap on the OTA so the dew can evaporate right now I just want to no if there is anything I can do to salvage my night or is it a lost cause at this point? Also any other pointers until my actual dew shield arrives in a few days. 

Edited May 14, 2023 by StarDuke82
Wanted to add that I have a dew shield coming and ask for additional pointers on dew control until then

[bosun21]

If you have a hairdryer you could use it to dry the corrector plate and put the make shift dew shield on. However I found that when the dew is bad I needed a heated dew shield to keep the dew at bay. Also on my eyepieces.

[StarDuke82]

I decided to pack it in for the night I tore the scope down and placed it inside it’s travel box carefully with the lens cap off and left the box open for the ride home I’ll set the scope up as soon as I get home and point the OTA down so the dew won’t spot and wipe the housing down if it’s still overly saturated but I suspect by the ride home the box I carry it in will catch more of the dew than will be left on the outside of the OTA as well as outside of my eyepiece case so I will toss a bag of rice in each for good measure and hopefully things will look better tomorrow. 
 

 

I do have a question though Dew forms on the lens much the same reason why frost forms on in the winter time except in the spring and summer it’s because the ambient temperature falls at or below the point of moisture available in the atmosphere, could you use say the same temporary solutions that work in the winter in the summer months glove warmers and insulating the OTA in combination with a Dew Shield or does the increase in moisture plus the warm temperatures necessitate a dew heater as the only solution? 

[PeterStudz]

As a beginner dew issues were something that took me by total surprise. It didn’t seem to be mentioned (might have missed something) in any of the beginner guides and articles that I read and I read a lot. First time I encountered dew I thought it was atmospheric fog

I have reflectors but I’ve found that decent dew shields (unheated) are enough to keep dew at bay - so far - although might have been lucky. And I’ve done all nighters where I’ve left the OTA out all night. 

Prevention is better than cure. The first sign that there could be problems is dew on the finder. I have a finder dew shield but if I leave the viewing/eye end uncapped that can dew up. So always cap when not in use. 

For eyepieces I have a jacket with a large front pocket. There’s enough heat in there to prevent dew on my eyepieces, so when not in use they always go there. 

 

[bosun21]

I recommend you get a heated dew shield or Celestron sell a dew ring which replaces the existing ring around the corrector plate. These work great. Regarding eyepieces if I have an eyepiece being used for a length of time then it also forms dew ruining the view. It all depends on how bad the problem is on the night. Reflectors aren't as prone to dew and you will get away with a dew shield. I owned a C8 and was plagued with dew until I took the above steps. On bad nights I also used a heated dew band on my eyepieces. HTH.

[Mr Spock]

Interesting how people's conditions differ. I never get dew - probably because I'm on a hillside.

[PeterStudz]

1 hour ago, Mr Spock said:

Interesting how people's conditions differ. I never get dew - probably because I'm on a hillside.

I almost always slap a dew shield on anyway. Even without dew it does a grand job of keeping out stray light. And for low contrast work, eg the plants, there’s a slight but significant difference. 

[Paz]

It was more dewy last night where I am than it has been recently, by the time I came in I had dew on the outer OTA of my C8 and on the finders but scope and eyepieces were ok. A dewshield protected the scope and my head works fine as an eyepiece protecter/heater, but when my finders started to dew up I knew the scope corrector plate would have been next soon enough if I had kept going.

[Cosmic Geoff]

Dew shields are a non-optional accessory for SCTS, just like refractors always have a dew shield.  The reason manufacturers don't provide them for SCTs is presumably because it makes their product look ugly and adds a small cost.  

Depending on the depth of your pocket and the severity of local conditions, you can use a home-made cardboard or foam plastic shield, a purchased dew shield, or (in the case of Celestron) a smart-looking black metal shield and a heated ring that replaces the corrector plate retention ring.

The dew shield works by preventing the relevant parts of the telescope radiating heat to the (very cold) night sky and becoming cold enough to condense moisture.

[Guest]

What kind of dew protection you needs depends on your local environmental conditions.  Some people can get away with very little, myself i run three dew bands most of the time.  You can make a dew shield out of foam for a little bit of nothing, it may be all you need, or you may need heat.  Heck there are even times that i put my dew shield on over the OTA heating band.  Keeps stray light out and acts like insulation for the band.  

[StarDuke82]

I live in the southern US it’s like the Amazon in the hot 90-100 *F (32-35 C*) with steamy humidity with pop up storms almost every afternoon. Winter is full of cool damp evenings and fog so if I am going to get the most out of my telescope it looks like a dew heater of some type would be a wise investment based on last night’s viewing conditions and the advice of everyone here. I am already looking at options the Celestron replacement collar dew heater interesting though I am not sure how confident I am at removing the collar holding my corrector plate in place, I may just get one that slips over the OTA and save that one for later on when I am more adept at customizing and modding my own scope. Thank you all for the advice and some tips I will try tonight to help keep me out under the skies until my dew shield arrives. 🤗

[Guest]

27 minutes ago, StarDuke82 said:

I live in the southern US it’s like the Amazon in the hot 90-100 *F (32-35 C*) with steamy humidity with pop up storms almost every afternoon. Winter is full of cool damp evenings and fog so if I am going to get the most out of my telescope it looks like a dew heater of some type would be a wise investment based on last night’s viewing conditions and the advice of everyone here. I am already looking at options the Celestron replacement collar dew heater interesting though I am not sure how confident I am at removing the collar holding my corrector plate in place, I may just get one that slips over the OTA and save that one for later on when I am more adept at customizing and modding my own scope. Thank you all for the advice and some tips I will try tonight to help keep me out under the skies until my dew shield arrives. 🤗

Yeah you will need all the help you can get probably.  You will want a heater for the OTA, finder and eyepieces.  A heated dew shield might be one way to go as it will act like a light shield too. 

[Elp]

1 hour ago, StarDuke82 said:

Celestron replacement collar dew heater

This is the singular most essential piece of kit for a Celestron SCT, clears up dew very fast as what can be better than a heater directly in contact with the corrector plate? It is very easy and quick to fit, a literal 5 minute job.

Edited May 14, 2023 by Elp

[bosun21]

You just point your telescope straight up and then the corrector plate doesn’t move. It’s a piece of cake and works fantastic.

Edited May 14, 2023 by bosun21
Typo

[Guest]

21 minutes ago, bosun21 said:

You just point your telescope straight up and then the corrector plate doesn’t move. It’s a piece of cake and works fantastic.

When did I say that?  I dont have anything with a corrector plate? 

[Guest]

3 hours ago, StarDuke82 said:

I live in the southern US it’s like the Amazon in the hot 90-100 *F (32-35 C*) with steamy humidity with pop up storms almost every afternoon. Winter is full of cool damp evenings and fog so if I am going to get the most out of my telescope it looks like a dew heater of some type would be a wise investment based on last night’s viewing conditions and the advice of everyone here. I am already looking at options the Celestron replacement collar dew heater interesting though I am not sure how confident I am at removing the collar holding my corrector plate in place, I may just get one that slips over the OTA and save that one for later on when I am more adept at customizing and modding my own scope. Thank you all for the advice and some tips I will try tonight to help keep me out under the skies until my dew shield arrives. 🤗

I am 600 miles north of you in Ohio.  Dew is a real thing here.  Some nights it looks like i have been out in the rain.  So i feel your pain 

[bosun21]

 

1 hour ago, Mike Q said:

When did I say that?  I dont have anything with a corrector plate? 

Don’t know how that happened 😂 It wasn’t meant for you. It’s for the OP. Sorted!

Edited May 14, 2023 by bosun21

[Guest]

9 minutes ago, bosun21 said:

 

Don’t know how that happened 😂 It wasn’t meant for you. It’s for the OP. Sorted!

No corrector plates needed on a dob lol

[StarDuke82]

20 hours ago, bosun21 said:

You just point your telescope straight up and then the corrector plate doesn’t move. It’s a piece of cake and works fantastic.

Thanks for the easy explanation without the off putting disclaimer in the installation video on the website makes it seem a lot less complicated and I decided that it’s the best solution overall, and ordered one for my SCT until either order arrives guess I am going to pull out my old Newtonian as only ever had dew problems with it my secondary frosted over a few times in the winter months but until my means to control dew gets here looks like it will be the best option if I want to observe, my Newtonian is probably better by far than SCT for viewing the Hercules Cluster and other DSO anyway might need start taking to two scopes out with me. 🤣🤣

[Guest]

On 14/05/2023 at 16:38, bosun21 said:

 

Don’t know how that happened 😂 It wasn’t meant for you. It’s for the OP. Sorted!

You have been drinking again havent you

[VNA]

On 14/05/2023 at 02:06, Mr Spock said:

Interesting how people's conditions differ. I never get dew - probably because I'm on a hillside.

 

Hello, or live in a drier place like the SouthWest U.S. AND on a hill!  ;- )
There are excellent dew shields with an absorbing lining.