Heating Eyepiece Boxes?

[Paul73]

Hi Guys

I am a new convert to the world of electric dew control. Secondary sorted (bought). Telrad sorted (home brew). But he other night I had issues with condensation on the outside of the eyepiece lens. I can't be doing with swapping dew straps every time that I change an eyepiece. So I wondered if it is worth heating the entire eyepiece case? If so. How?

Thanks

Paul

[Norfolk star gazer]

I was thinking the same this morning at 6am when my case was dripping wet and each EP I took out needed wiping.

I did try to keep the lid shut when possible, but was constantly in and out of it.

Couldn't think of an electrical solution (apart from a hair dryer) so was thinking that maybe something portable that can be heated prior to going out and keeps warm during the session could be fixed inside the lid. It would have to be something flat so that the lid shuts.

Ideally the thing can be microwaved (just in case you need to reheat it quickly) so was thinking about a heated pad of some sort.

I'm sure that I nave seen them somewhere (heated neck pad maybe?)

[Paul73]

Yes. That is probably a simpler solution.

I was thinking about making a heater strip to go in the lid of the case to gently keep the chill off things (running off the telescope dew controller).

Think that I may have been over-complicating things.

Paul

[Demon Barber]

Paul ,using a heater band is the way to go,terminate in a socket on  the outside of your chosen case ,to the extreme of using an old ice box (insulated)with a heater band inside it..You can always use hand warmers to boost initial heat.

Regards

Mike

[Mr Spock]

Pockets, lots of pockets

[jason.p]

Pockets, lots of pockets

I've got a dedicated eyepiece coat (one of the few that isn't full of brick dust ) with enough pockets to accommodate four eyepieces. It took me a while to remember which one was in which pocket, but does the job. I usually slip the Barlow in a trouser pocket.

[Paul73]

Yes. A dedicated coat would be ideal. I used to do this with my normal coats but found that pocket fluf / dust seems very adept at getting into sealed eyepieces!

Paul

[cjdawson]

How about something like this?

http://www.amazon.co.uk/s/?ie=UTF8&keywords=deluxe+zippo+hand+warmer&tag=googhydr-21&index=aps&hvadid=90309878214&hvpos=1t1&hvexid=&hvnetw=g&hvrand=421131156980159178&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_3qychuptao_b

I've got a couple that I use for my hands when it's cold out.  It might be worth trying in the box - provided that it's not airtight.

[Paul73]

Hmm. Not sure about in the box. But I'll certainly try them for my hands!

Thanks

Paul

[Demon Barber]

Paul,they are great for pockets,but use the sealed gel types only to go in the box,no risk of explosion!

Mike                                                                                             

[cjdawson]

lol, explosion?  Erm, the worse that is likely to happen with them in a box is that they'll go out.  For starters there's no flames.  The hot part is also completely surrounded by metal., and the bag - which is needed to make it work well.

The gel ones would probably be plenty for an eyepiece box.  As would the single use disposable ones too.

[Norfolk star gazer]

Found this on Altair Astro.

http://www.altairastro.com/kendrick-eyepiece-box-heater-pad.html

[cjdawson]

That's cool.  but 0.8 Amp.  From a 17ah battery, it'll last about 21.25 hours.  Which is good enough for a whole nights observing.  But, if you are using the same battery for everything else, it'll be probably about 1/2 the overall power that you'll use.

I know my scope uses about .2A (when tracking, slewing is higher) my heaters are .2 each (ish under normal use, but can go much higher)  then my synguider is .15 and my SkyFi is .15 as well, so in total that's 0.7A.

Thinking about this, it would be worth getting a dedicated battery just for the eyepiece heater. 

Something like this...

http://www.amazon.co.uk/Rechargeable-Li-ion-Battery-6800mAh-Charger/dp/B00BWW9WRM

Would give you about 8 hours of heating for your eyepieces.

[Paul73]

Now that is an absolute cracker of an idea. That can go under some of the slimmer eyepieces. Might even add some dim red LEDs for map reading.

Paul

[Paul73]

Found this on Altair Astro.

http://www.altairastro.com/kendrick-eyepiece-box-heater-pad.html

Looks good. I could knock something like that up for about a fiver!

I wonder if you can put them under astronomers as well as eyepieces?

Paul