Dew control

[PatG]

What are people using for dew control. Is a 12v hair drier suitable for use, or is this something to be wary of? 

 

[Carbon Brush]

A 12V hair dryer is a good low cost start to dew prevention/removal.
Safe outside when damp and not the 'melt everything' power of a mains hair dryer.
It can be used on any part of the scope assembly.

Don't forget they typically consume around 15A or more.
You need a decent battery (car or leisure), fuse or coircuit breaker and GOOD quality connections.
Forget powerbank type of products that are only intended for a fraction of this power.

The reason for stressing connections is that the average (poor quality) cigar plug product is going to produce more heat than the hair dryer!
You don't want to be handling hot molten plastic or putting out flames.

HTH, David.

 

[Zermelo]

Look for a 12V version that has at least a "low" and "high" setting. They can draw around 15A on maximum, so a lower setting is conevenient to have available.
If you have a powered mount, then even if your power supply is rated for the total current you need, ideally get a separate supply for the mount, and another for dew straps/hair dryer/etc, as some mounts can be fussy about small voltage drops.

[iantaylor2uk]

I use fairly cheap CooWoo 5V USB dew straps from Amazon (which have low/medium/high settings) on my guide and main scopes, with one USB plugged into the mount and the other into a USB hub on the back of my ZWO camera. This works quite well for me, but you would need bigger straps if your scope objective diameter is more than 110mm.

[PatG]

Thanks for the advice all. Need to consider the power supply situation… more adapters! 

[Davesellars]

Depends what the scope it is is or dealing with dew on eyepieces?   I've found that preventative action is preferable to dealing with once it's dewed up.

I do have a battery that I used considerably more when I had my 8" SCT for a heated dew-shield as that thing was just impossible to keep dew at bay otherwise and I was observing in a particularly damp area.  Now I use it for the worst of nights with a small dew-strip mainly for the finder eyepiece and occasionally to dry an eyepiece if dew has caught it.  However, I use a preventative measure of keeping the eyepieces in a closed Peli case when not in use,   Since my oberserving style is changing eyepieces reasonably frequently -  I hardly ever have to dry off dew on an eyepiece.

My 60mm finder can pretty much go all night without dewing up as I put a home-made dewshield from some foam on it.  For my refractors had a similar solution until I lost them - however these normally get used for shorter sessions anyway but I could use one again for the 120mm ST anyway.

My 12" dob primary mirror has never ever dewed up...  The secondary will dew up if the it's quite bad (again I resolved the issue previously with a home-made foam dewshield which again got lost in the house move).  I need to get a new one sorted out as this does cut short my sesssions at times!

[Guest]

I use the Orion dew zapper on my 10 inch dob.  Yeah it is the expensive route but dew and frost are a non-issue now.  

[PatG]

Thoughts of dew control situation followed recent sessions with a 200mm SCT, during brief session on Friday night the corrector plate, eyepiece and finder had all dewed up within a couple of hours or so. Tempted to invest in a proper dew control set up but as often alternating between couple of scopes the thought of a small hair drier cross my mind. 

[That Bear Guy]

yeah, I’m new to the game but got pretty sick of my nights being cut short by dew on my 125 SCT corrector plate

Saw some cheap, but good quality solutions on www.dewcontrol.com - found them on the reviews pages on SGL

The guy there is an absolute star. He’s quite happy to customise connectors (within reason) and I would imagine cable lengths as well.

last Friday on the Devon moors became dew free using their Duel channel controller and dew strap at only 20%. Using the accessory power cable output solved a long standing cable wrap issue for me as well so no more disconnected power to the mount!

worth a look ? you could potentially get a set up for each Scope as easy to move the controller and leave straps in situ

I’m using this for portable power which provides ac but is completely overkill for one mount and a controller, it’s unavailable now but there are similar options about at lower capacity and cost.  

 

TBG