Celestron dew ring?

[Seoras]

Does anyone have experience of the Celestron Dew Ring, the thing that apparently replaces the holding ring on the corrector lens? I was out last night and had my first encounter with dew (I live in Scotland 🏴󠁧󠁢󠁳󠁣󠁴󠁿). I’m brand new to the hobby so trying to learn as I go, as such, I’ve seen dew shields both home made and branded but I don’t know how much difference there might be between making your own from a yoga mat or a fancy Celestron one? Any advice on this topic greatly appreciated, 

 

thanks, Geo

[GuLinux]

I just got one for my new C11.

I can't really speak from experience, as I only used it once, but can I offer these few points:

• it can't be compared to a dew shield (either homemade or branded), as they serve slightly different purposes. A dew shield will just slow down dew formation, but it will eventually form if the air humidity is high enough, especially if you have a large front lens. The dew heater is an active component, meaning it actually warms up the lens to prevent dew formation (given you provide sufficient power). So the right comparison is between the dew ring and the less fancy dew heater bands you can find for various telescopes. In fact, in the manual, they advise to use the dew heaters in conjunction with a dew shields, as this will allow the heater to operate more efficiently.
• If the choice is between the dew heater bands and the dew ring, keep in mind that the dew ring is especially designed for your celestron SCT, and more efficient. In fact, the main difference is that the dew ring will warm up the lens, as opposed to the regular bands which will only warm up the tube. Eventually, some heat will also warm up the lens, of course, but there'll be heat dispersal, which isn't ideal. The cons for the dew ring are that it's slightly more expensive, not reusable (as it's designed for that specific scope only) and require some assembly (nothing too difficult though).
• Another cons is that the thermistor built in in the ring is only compatible with the celestron smart controller. If you have another controller (DIY, Pegasus, etc) you can still power the ring, but you won't be able to get a precise temperature. I guess you could extrapolate the operating parameters and tune your smart controller, but as thermistors are fairly inexpensive my approach will be to just replace it with another one of known value.

[Elp]

I've got the Celestron dew ring installed on my C6, it's quick and simple to fit. When it dewed over once, I plugged it in and it cleared within 5 minutes. I also use it with a dew shield as any scope with large front glass needs this as an additional preventative measure as well as keeping stray light off the optics.

[Seoras]

Thanks for your help. I understand a bit better now about the differences and that I would be best to fit both a dew ring and a dew shield. GuLinux; good to know about the compatibility of the Celestron Dew Ring, my intention is that my Nexstar 8SE will be my one and only scope but I suppose that’s unlikely given the nature of the hobby! Elp; glad to hear you’re having a good experience with the dew ring, I think that’s the way I’ll go along with a dew shield. Boy, this is an expensive hobby……

Geo