dew straps any good

[iwols]

hi daft question but do dew straps actually work and where on an ed80 does the strap fit,cheers

[PeterCPC]

Yes they do. On my ED80 I put it around the dew shield about where the objective is.

Peter

 

[iwols]

thanks do they effect the image quality with the warmish air peter

[wookie1965]

AS Peter says yes I put 2 on my Tal 100rs around the dew shield right where objective lens is keeps it dew free. 

Paul 

[PeterCPC]

1 minute ago, iwols said:

thanks do they effect the image quality with the warmish air peter

No. I have not found that at all - it's not very warm - just enough.

Peter

[iwols]

 i also have a c8 would i be better getting one for that and wrapping round twice on the ed80 or would that be too much cheers guys

[PeterCPC]

Go for two seperate ones.

Peter

[Davey-T]

Just bought a very nice looking one from 365Astronomy, cable comes out at right angles rather than out of the end, hopefully I'll get to try it if this fog ever clears.

Dave 

[iwols]

just ordered one guys 30cm and controller,if i ever get tuo use it

[barrie greenwood]

Well I'm a bit tight ?

What I've opted for is a 2mtr length of heat trace that is wrapped around the whole Ota twice at the top spiraling down and twice at the bottom near the prime it keeps it dew free all night, the only problem is that it's 240v  (not an issue for me in the garden )

This cost me £30 and you can also get shorter lengths 

Just another thought on it

Baz

[iwols]

Thanks guys bought a controller with it though not sure if that was needed or not. Do  they work without

[faulksy]

3 hours ago, barrie greenwood said:

Well I'm a bit tight ?

What I've opted for is a 2mtr length of heat trace that is wrapped around the whole Ota twice at the top spiraling down and twice at the bottom near the prime it keeps it dew free all night, the only problem is that it's 240v  (not an issue for me in the garden )

This cost me £30 and you can also get shorter lengths 

Just another thought on it

Baz

very dangerous though. using 240v outside in the damp air not a good idea, hope you use a tested R.C.D.

[barrie greenwood]

Yea it's running through an rcd and is Ip65 protection rated

[Davey-T]

2 hours ago, iwols said:

Thanks guys bought a controller with it though not sure if that was needed or not. Do  they work without

Better with controller as you can regulate the current, I set mine as low as possible to save battery power, and if youve got more than one plugged into the controller it saves having so many trailing cables.

I have my controller velcroed to the top of the scopes on dual rig.

Dave

[MARS1960]

They work great, just make sure the lead is long enough.

I had one that came with a scope i had to fit around my guide scope and that has a fairly long lead, the one i bought from flo has a lead half the length and it really isn't suitable but i'm making do by fixing the control box to my OTA with velcro.

[iapa]

On 19/12/2016 at 11:47, iwols said:

hi daft question but do dew straps actually work and where on an ed80 does the strap fit,cheers

most definitely, 

I forgot it the second night I took mw new ED80 - and it frosted over.

Two hours with dew strip on and all clear - except it was also dawn

[Skipper Billy]

This is where I put it on mine - just where the objective lens is. The 4 channel controller is velcroed to the OTA.

You can run it dierctly off 12 volts ie no controller but it will always be on full tilt which will almost always be too warm - it only needs to heat the lens to about 3 - 4 º above the ambient temperature. Too much heat wastes energy and can cause warm air currents in the OTA - as little as possible works best.

 

 

[iapa]

@Skipper Billy

A box with a lift off lid?

Brilliantly simple.

[iapa]

On 19/12/2016 at 12:56, barrie greenwood said:

Well I'm a bit tight ?

Aberdonian? 

LOL

[Skipper Billy]

46 minutes ago, iapa said:

A box with a lift off lid?

Even simpler than  a lift off lid - hardly any effort required at all....... click the photo to see more..............

 

[Skipper Billy]

Hmmm link not working - try this - 

https://www.flickr.com/photos/113316085@N05/albums/72157663274320360

 

[iapa]

you dont have a sideline in building these do you?

LOL

 

[Skipper Billy]

6 hours ago, iapa said:

you dont have a sideline in building these do you?

LOL

Not until I retire !!!

Not difficult though - a few lengths of 2x2 from Jewsons and shiplap and you are in business !! The hardest part is getting the hinge points right so that the roof sits right when open and when closed.

Good fun project for the summer when there is no imaging to be done??

[Tim]

I'm thinking this thread will get viewed lots of times in the future

Dewstraps are a staple item really for UK viewing. For Refractors, Maksutovs, SCT's, anything with a front lens they can work very well. 

A little care needs to be taken on shorter straps not to get them so warm that they introduce air currents into the view, or worse, distort the lens in the cell and ruin the views. Longer straps tend to stay cooler anyway.

For SCT's and Maks the Astrozap dewshield with built in heat strap are great

https://www.firstlightoptics.com/dew-prevention/astrozap-flexi-heat-dew-shields.html

You can also get them in shorter lengths to go around eyepieces, camera lenses, finder scopes, and so on.

As stated above, the controllers let you fine tune the output, and just enough warmth, is enough. Just need to raise the local temperature above the dew point.

Tim