Dew control in a roll off roof

[des anderson]

Hi guys,thinking of getting a observatory,and I`m aware that they suffer from dew with the roof rolled back,so please what`s the best way to combat this,and is there any special measures that needs to be done to keep the tube and optics dry after using them,I use a dew shield at the moment,will i need to up grade???Telescope is an 9.25 sct Des

[Garethr]

Des

A quick blast with the hairdryer and lens cap on

roof back shut down and bed seems to work for me.  

Gareth

[Owmuchonomy]

As Gareth says or as I do now and use a Kendrick dew band as well as a dew shield. Dew doesn't form on my corrector plate under these conditions. It does however form on the mount but my roll off has good airflow when shut so dew soon dissipates after a while.

[perfrej]

And leave the stuff powered on under those conditions...

[ollypenrice]

I doubt that passive dew prevention will ever be enough for an SCT and would always suggest dew heaters. For your electronics you can buy low consumption pet warmers quite cheaply. I'm not making this up...

The other big thing is to keep the air circulating.

Olly

[rrb24]

Install a dehumidifier. I run mine at the end of each session for 3 hours in the morning. Dew heaters stay on every single night even if no imaging. I have two mounts in my RoR: one for imaging, one for visual. The equipment in the visual is usually very wet come the morning as it gets used less but the dehumidifier does a good job drying everything up.

Roberto

[peroni]

I run a tube heater in mine connected to a thermostatic switch. I occassionally change the temp to keep things just above dew point. Obsy is nice and condensation free.

[Tim99]

Thanks for this thread Des.  I am planning to build my Obsy in the springtime and hadn't thought about moisture problems.  I have a dew heaters for the SCT but perhaps the de-humidifier is a good idea.  During cloudy weather there may be days that I will not be at the Obsy.  

Thanks for the heads-up.

[r3i]

I run a tube heater in mine connected to a thermostatic switch. I occassionally change the temp to keep things just above dew point. Obsy is nice and condensation free.

There's usually enough air flow in my observatory to keep the dew at bay but on the odd still night the gear does get covered so I use a tube heater placed next to the pier to help dry everything out.

[des anderson]

Hi guys,thanks for the info,lots to thing about....I was not going to put power into the observatory,as it`s at the back of the garden,and just rely on my power tank for running my mount.

[Tinker1947]

Last winter i had a rubber 2 part roof covered in rubber, it opened to the front and back, it did collect dew on the underside, i think attempts at  prevention was covered in another thread, so last summer i converted the 2 part rubber roof to a single polycarbonate roof angled so the rain runs off and it doesn't need a apex due to the light weight, now for the winter dew protection it hasn't as yet had any and the scope mount and other gear are nice and dry mostly due to the slightest sunshine warming the interior through the polycarbonate, In the summer it will heat up but its the dew and damp that does the damage.......

Picture while open.....