DIY Dew Shield for my Meade LX90 EMC 8" SCT - using a thermal (foil-backed) camping mat

[newbostonian]

UK suppliers all seem to be out of the right sized dew shield for my 'new' Meade LX90 EMC 8" SCT (other available brands' offerings look a bit thin and unhelpful) and I gather from chats on this site that dew is going to be a massive problem in Winter in the North of England, so I've taken the advice of numerous posters and ordered a foam camping mat to make my own. I looked into the adhesive-backed flocked/felt fabric to line the inside, but I found a rather handy 'cheat' that I thought I would share in case it actually works! There's one foam camping mat (Trail brand) that's black AND has a thermal foil backing, so I'm going to try it (with the thermal backing on the outside of course) in the hope that that might help further and might avoid having to use a dew heater or fan arrangement as well. This mat is also 1mm thicker than usual at 7mm. Although I have plenty of black Velcro, I've ordered an industrial strength adhesive-backed version for securing the foam tube together. Although it's purportedly for outdoor use, I imagine I'll need Gorilla tape instead outside in the cold and damp. We'll see. Supplies should arrive next week. 

    https://www.amazon.co.uk/dp/B0957MHS4D/ref=pe_27063361_485629781_TE_item

 

[Joe G]

Good idea, I need one for my dob so let us know how you get on with the project 

[Cosmic Geoff]

I find that even cardboard works quite well for a dew shield, so there is no need to spend money on it if you are a tightwad.

[symmetal]

I've made a couple of dew shields for RASA scopes using similar material and used 3M Super 77 spray contact adhesive to stick the ends together with a 5cm overlap. Works very well with no sign of it coming apart despite several very dewey nights. To keep the circular shape I 3D printed a band to slip over the front of the shield which works well. 🙂

Alan

[newbostonian]

An update on the 'black' foil-backed foam camping mat - it arrived and it's grey! So it would still need blackening really. It's a shame as the detachable elastic strips and holders to keep it rolled (which are black) would have worked well to hold it in place without additional attachments.

A first night outside with the 'scope at -7 degrees and it didn't dew up anyway. Nor did any of the eyepieces. I'd left the 'scope outside for an hour or two prior, but I don't think I really needed to as I live in an unheated Victorian house and when I came indoors at 2am it actually felt colder inside than out!

[newbostonian]

On 10/12/2022 at 16:26, Cosmic Geoff said:

I find that even cardboard works quite well for a dew shield, so there is no need to spend money on it if you are a tightwad.

Thank you Geoff,

I have a large roll of corrugated card, so I might just have a go!

[Karl Perera]

I think that the dew shields sold online are really pricy considering it would be easy to construct one from black plastic or similar material and then stick two peices of velcro on each end. Just wrap around the scope aperture and off you go!