Anti dew supplies

[MarkInSpace]

I had my first real “dew drama” of the year and decided enough is enough! What’s a good and cheap source for anti dew straps?

[multiweb]

kendricks

[Imme]

Depends how inventive you want to get......

My setup features a beer keg warmer and light dimmer switch (240v)

On full power it would almost boil a kettle I think!

[AdamJL]

SVBony :)
I have a more expensive Prima Luce one for the main scope and I decided to buy a SVBony one off ebay for the guide scope. The latter is USB powered, has three power levels and I think I paid $30 all up. The Prima Luce was $109 which also required a power regulator which was $69.

Crazy.

A 400mm strap (your 115mm scope should have a circumference of 360mm) costs $38 on ebay

https://www.ebay.com.au/itm/SVBONY-SV172-400mm-Dew-Heater-Strip-for-Telescope-Lenses-Temperature-control/313424380011?hash=item48f98c806b:g: EzAAAOSwZsFgBkIE&frcectupt=true

[RB]

I use a 'Dew Buster controller'.
So many outlets and plenty of options.

https://www.dewbuster.com/default.html

Couple that with the Kendricks straps.

Awesome.

:thumbsup:

[mental4astro]

There actually is a no-heat solution!

Refractor dew control WITHOUT heat - it is possible! (http://www.iceinspace.com.au/forum/showthread.php?t=182093)

Effective, far less power requirements, and more efficient.

If you can set up in a location that has less propensity for dew even better - dew and astro are not inseparable bed fellows. Of course this depends on your situation as to whether or not a different site is a practical option or not. For me, setting up from home means dew is a frequent problem, whereas at my dark site dew is very rare - in 14 years dew has formed 6 times, with only once being heavy enough to trouble scopes. From home, I've been using fans now for pver a year with my 9" Mak & my refractors.

Fans with Maks & SCTs: SCT & Mak total dew control without heat - a solution! (http://www.iceinspace.com.au/forum/showthread.php?t=182057)

Heat is not the only solution for dew control. Professional observatories don't use heat, but fans.

Alex.

[N1]

Some great hacks there, Alex.
I imagine professional observatories use fans mainly because heating huge slabs of glass would involve such vast amounts of heat that the local seeing would be completely obliterated by it. That does not tend to be an issue with small (<1 metre) optics, which are much lower in mass and volume, and resolution.

[mental4astro]

Thanks Mirko.

It is not just the glass and localised seeing. These scopes are made out of materials for which the engineers know their precise expansion and contraction with temperature variations, and the equipment is designed to react to these predictable parameters. Add heat and these are no longer predictable as heat is not uniformly distributed. It also introduces IR to their equipment.

Thing with the use of fans is not to do with our scopes being less than 1m in diameter. It is that there is a way to control dew WITHOUT heat.

Amateur Newts and open tube OTAs have been using fans to great effect for many years now - how fans are used is critical though as incorrectly employing them actually induces thermal issues rather than avoid and prevent them. Certainly not my invention to use fans with scopes! I just worked out a way to use them with SCT's, Maks and fracs.

Alex.