Moisture Removal

[Astrolounge]

l would like to get some first impressions on these plugs l am making to remove moisture trapped inside sealed scopes like Cassegrains and refractors.
They are made from high grade plastic and use an O-ring to give an air tight seal, inside are replaceable Silica Gel sachets that draw out the moisture and prevent fungus build up especially in humid climates.
Any comments are greatfully appreciated.

[rogerg]

Interesting idea. Is the expected usage when in storage after a nights viewing, or out in the field for removal of internal condensation/dew partway through the night?

I guess the reason I ask is the latter would be more useful if they reacted quick enough, where as once the night is over it's easy to leave the scope's cap's slightly lose the next day to let moisture out.

[Astrolounge]

they could be used at any time although my intention would be to use them whenever the scope was not in use, if the following day is cool then the moisture will stay in the scope and not be drawn out.

[AstroTasmania]

Hi Astrolounge,

Excellent idea, I have been doing this for several years, both for scopes, optics and video cameras that have TEC cooling. I use the blue self indicating silica gel which turns pink when saturated, It can then be reused by short bursts in a microwave or slow baking in an oven until it goes blue again.

I got used to using silica gel as a desiccant during my years of med lab work and saw how useful it was in keeping moisture out of air spaced lenses, leaf shutters etc. With the increase in general humidity levels, its regular use will prevent rusting in hidden places as well as mold growth.

Pink gel is available for $90 per kilo compared to $30 per kilo for the blue.

I have mine in little nylon sachets that you can buy from art & craft shops.

Go for it, it is a well proved technique for storage and getting moisture out of hard to dry places. Leaving optics open allows ingress of dust and other foreign matter. The silica gel technique avoids that.

Clear skies...

[Radar]

That is a pretty good idea Astrolounge. Keep us posted on your progress.

[Tenacious Del]

I haven't really had a moisture problem before. But I haven't really been in those conditions enough. Looks like a great idea Astro Lounge. :thumbsupmate:

[AstroTasmania]

Most of last year, through the winter especially, humidity was frequently at 90%, any scopes used outdoors were dripping wet within a very short time. I have had to put extra insulation inside the dome as I was even having moisture issues inside! So, all my drawer units and camera, optical cases, OTA's have silica gel packets in them.

My automated all sky cameras Daytime & night time units (mounted in enclosed weatherproof housings with heater & fan) now have silica gel containers attached to the air breather to keep moisture from forming inside the acrylic dome.

These humidity levels are not usual but come with the constant cloud cover.

Clear skies...

[Radar]

Where can silica gel be bought from guys?

[AstroTasmania]

Hi Radar,

I buy my chemicals supplies from a laboratory supply firm in Hobart. You would have a similar supply place in Perth, they supply chemicals & lab /scientific equipment to labs, hospitals, university depts etc. The blue spherules cost me $30/kilo.

Clear skies...