Dew heaters (again)

[meddyliol]

Is it more important to have a Dew Heater on the finderscope or the eyepiece. I have bought one for the main tube and am going to make one for either the eyepiece or the finderscope but not both. Most, if not all, ready made bands are for the eyepiece so that suggests that the eyepiece is more important. But is it?

Thanks

Brian

[Herra Kuulapaa]

I'd heat the eyepiece first. You can always cover the finder scope to prevent if cooling too much.

[Starfisher]

if you got a goto or a pc - controlled  is the eyepiece the most important

but why not make them all once your busy?

[Herbig]

If you are only going to mane one make it to fit either then you can swap it over.

[johnoelliott]

I have heaters for both ends of my Celestron Evo 9.25 and my finder scope, no dew problems on the optics

[cjdawson]

Of the two, I'd agree with heat the eyepiece first.

however, there is another option... make an eyepiece box with an opening so that you can get your eyepiece out without opening the box to the whole night sky.  This will provide cover, much like a car port does, and should help to stop your eyepieces dewing up.  Nothing stopping you from adding a heater element to the box to heat all your eyepieces.

Personally, I've not had the need to add a heater to either the finderscope or the eyepiece.

A cheaper alternative, is to keep the eyepieces next to your body, in a pocket or similar.   That should have the same effect ;-)

[meddyliol]

Thanks for your replies. I could make one for the eyepiece and another one for the finderscope, that would mean heating three things at the same time. I mean, how much of a problem is dew? Is it worse in the summer or winter? Making a sort of universal one for eyepiece and finderscope might be a good idea. The problem with that is I have a 9x50 finder and 1/1/4" eye pieces. Is it OK to wrap around the eyepiece a few times?

Cheers

Brian

[spaceman_spiff]

Personally, I used to warm a dewed up eyepiece with my hand.

I found that both the finder scope and the eyepiece could dew up from the moisture from my eyes and face. I may be wrong but I seem to have more problems with dew in winter than summer although it depends strongly on the relative humidity and dew point on the night you observe. 

[meddyliol]

Personally, I used to warm a dewed up eyepiece with my hand.

I found that both the finder scope and the eyepiece could dew up from the moisture from my eyes and face. I may be wrong but I seem to have more problems with dew in winter than summer although it depends strongly on the relative humidity and dew point on the night you observe. 

But doesn't it cool down again when you put the eyepiece in?

[spaceman_spiff]

But doesn't it cool down again when you put the eyepiece in?

Unfortunately yes and you lose all feeling in your hands!  

Heaters would be the best option in the long term. I am currently building my own heater strips and controller - it's a nice project for a weekend.   

[meddyliol]

I have just threaded my Nichrome wire through some heat shrink tube (wasn't that easy) and calibrated my LED Dimmer (http://www.ebay.co.uk/itm/311357749899?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) so that I have rough idea of what wattage to expect at various positions.

Brian

[cjdawson]

Washing up liquid on the nichrome wire helps it to slide easier when threading through the heatshrink.

Turn your heater up to full power and it'll shrink nice and tight around the wire, but I'm sure you've already done that.

[meddyliol]

I did put the heater to full power but it didn't shrink it. Fortunately, I have a heat shrink gun which did the job. I would never have thought about washing up liquid.