Dew band, where do I fit it on a refractor?

[David010167]

Hi, I have ordered dew band/tape and controller for my Skywatcher ED80mm and the ST80 guidescope. My question is; where should I best place the band? After a poor imaging night a few weeks ago with great clear skys and a lot of dew/condenstatsion I thought I would try the heater tapes to see how much of an improvment it makes.

Does it go on the dew shield part of the scope infront of the lens, or should it go in line with the lens or behind.

I am guessing infront on the dew shield/lens hood.

Also, how do you know what temperture to set the bands to? In theory it should a few degrees warmer than the dew point, but how do you know/control this, or is it down to experience?

regards

David

[SlipperySquid]

I was informed that the best placement for the bands is just behind the lense cell (on the dew shield).

I use dew bands on my finder and finderguider and don't have any problems with dew anymore! as to heat setting I can't help you there as I just set the bands so that they feel warm and if I still have a problem with dew I up it a bit but since I set the box months ago I havent touched it since!

Sorry I can't help anymore

Matt.

[David010167]

Thank you for the fast response As soon as they arrive I will have a play and see what works.

regards

David

[Talitha]

When i got my dew tape, the instructions said to place it 'just behind' the lens on a refractor, or 'just behind' the corrector plate on a Mak or SCT.

Works great.

[msinclairinork]

I think Matt i correct in saying they are meant to sit just behind where the primary lens is.

For temps...i have pondered that one my self..you are correct in saying the ideal temp to set it at is just above the dew point, which can be calculated from knowing the ambient temp and the humidity factor, but knowing what tempreture your bands are in the many different nights tempreture and settings available...few not a clue apart from sitting out everynight of the year testing and making a chart?!

What i do think people tend to do though is just set on ....2 for example because they have found it works for them and if you find your subframes are distorted then you would obviously turn it down.

I opted myself for the 'Dew not' basic controler that didn't have any variable settings thus eliminating this conundrem

I was infromed though that it would be all i would need and so far that has been the case so on premise I am guesing you will just find that one setting that does the job 90% of the time, but you have the option to tweak it to make it work 100% where as I don't have that option.

Happy tweaking!

Michael