Dew heater recommendations.

[Smithfire]

Hi everyone

I use a 127 Mak and need a dewing solution. Dew shield, heater tapes, controller and power supply. Whats good, how much and where from.

Many thanks 

Clive

[ChrisLX200]

A dew shield is a must-have, made yourself from some foam sheet (camping groundsheet). That would take care of maybe 80% of your problem, the heater would take care of the rest. You can DIY a heater or buy a commercial unit, a simple 2-channel unit would be fine.

ChrisH

[baggywrinkle]

If you go for the camping mat solution which is very cheap and easy, make sure you use a black mat. I used a blue one and it actually caused some image degredation as I got some stray light reflection on the inside.

If you can use a matt black spray paint as well so much the better.

Focus plates on Mak's and SCT are dew magnets.....

[Pete Presland]

I have dew shield for my c9.25 it helps keep it at bay for quite a while

Sent from my GT-I9100 using Tapatalk 2

[Smithfire]

Surely if you spray the inside of the mat with paint, aren't you going to stop it being hydroscopic? I thought they worked by absorbing the dew?

Clive

[glappkaeft]

No, a dew shield just limits the flow of moist air across the lens (or telescope opening).

[Smithfire]

Then why make them out of foam matting?

Clive

[glappkaeft]

It's a cheap, light and easy to work with material. Foam matting doesn't absorb water to any noticeable degree, if they did you would want to sleep on them.

[Killie]

I was lazy and just bought a pre-made Dew Shield and it has been a god send. So far managed to avoid needing a heater yet but to be honest i have only been doing 3 hour sessions at the most.

[Smithfire]

Hhhhhmmmm.....you learn something new every day!

Clive

[DannyHarvey]

This makes a fantastic dew heat control if you can manage the mounting in a box:

http://www.maplin.co.uk/p/mfa-panel-mounted-speed-regulator-module-rn41u

Saves the pennies...

r.

Danny

[DannyHarvey]

There is even cheaper ready made circuits out there...

[Smithfire]

Have you made that module into a heater control Danny?

Clive

[DannyHarvey]

Yes  yes I did! - it works great:

[DannyHarvey]

Its not the exact same module here (although the circuit is identical) - the one I linked is the one with the panel mount pot on it. I got the same unit but with a little mini pot on it, which I had to remove and add a panel pot. Essentially I got the wrong unit (duh!) meaning I had a bit more work to do. If you get the linked one there is no re-soldering to do whatsoever.

Dan

[Smithfire]

Good work mate!

what do you use to power it?

Clive

[DannyHarvey]

Straight on to  a 7.5AH 12 V battery - sits on the EP tray on the mount - Although I have just bought a 15AH power tank from Maplin

[Smithfire]

How much was that? And would it run the drives in an EQ5 as well as the dew heaters?

many thanks for the info!

Clive

[faulksy]

This makes a fantastic dew heat control if you can manage the mounting in a box:

http://www.maplin.co.uk/p/mfa-panel-mounted-speed-regulator-module-rn41u

Saves the pennies...

r.

Danny

i used 3 of those pwm and housed them all in a box, you can see them mounted on the ep tray

[DannyHarvey]

wow that's a monster!