Dew heater for 150p Skyliner

[Cazz]

Hi all,

We've recently bought a 'preloved' SW SkyLiner 150p Dob. We've been looking into dew heaters for it, now my question is - how do you fit one to the secondary mirror on the 150p, there is barely any mirror that isn't covered by the bit that holds it on.

Has anyone found or know of a special way to do it, or is it an impossible task please?

I have mad dew shield for it, but we've yet to test everything out for more than a couple of hours to see how bad it gets. So far we've obviously only used on warmer nights.

Thanks in advance for any thoughts, ideas or suggestions.

[FarSide]

You don't place a dew tape around the mirror, Cazz, the tape goes around the telescope itself, and is regulated by a dew heater controller. For a 150p you will only need one to keep your scope above dew point. Nothing ever has to be fixed to any of the mirrors.

Mike.

[cotterless45]

I'd just stick a dew shield on, if dew conditions get that bad, then everything will be affected ( in the whole Universe!),

Nick.

[Cazz]

Would putting it round the tube and not the mirror work on a reflector?

And fair point about everything being affected, can an beginner notice a different between damp in the air and dry air? (Assuming you're fogged up of course, lol)

[Cazz]

That should read, not fogged of course, lol.

[RikM]

Try it with just a dew shield first. You should be okay on any but the dampest nights.

I have not seen a Newt with a heater band around the tube, but I have seen a few larger ones with mosfets or resistors glued to the back of the secondary and the wire taped to the spider leading to a hole in the tube and down to a battery and controller. I would make something similar myself but I use my Newtonians for imaging and I am not sure if the wire in the optical path would create nasty diffraction effects.

[FarSide]

More of then than not your newts tube will protect your primary and secondary mirror from all but the worst of dampness. Refractors are a different kettle of fish and dew up quite quickly in damper conditions. This is when the strips come in handy.

[Cazz]

Thanks for that, that sounds like a plan. We'll see how the home mod dew shield works, and take it from there. But if the secondary mirror does due up, I think it's going to hard to heat the glass due to lack of room on the back, unless we get a hair drier of course.

[FarSide]

If you feel your secondary dews up quickly strap on a dew strap and see if it makes any difference, it should do.

[Cazz]

We've only had it a few weeks, so it and it's quirks and issues are all waiting to be discovered by us. Based on what you've said, fingers crossed it'll be ok, the big test will be at Kelling.