From: Alan Friedman <alan@greatarrow.com>

Date: November 23, 2005 9:48:41 AM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: What about the dragonfly 2?

On Nov 22, 2005, at 8:43 PM, Tim wrote:

P.S.  Alan.  I bought a Kendrick dew heater with the basic controller a couple weeks ago, 

and next to the Robofocus, I find it's the most useful accessory I've added so far.  I set it at 

the lowest setting, which kept dew off the optics the whole session, and the seeing got 

"good" and stayed that way for a couple hours.  Before, I had to equilibrate again between 

"blow drier events", and in reality must not have achieved it before the corrector dewed up 

again!

Hi Tim - A dew heater is a very important accessory - but I use it mostly if I will be out for many hours or up all night at a star party. At home imaging sessions I usually set the alarm and get up for an hour or two. I set up my my equipment ahead of time and leave it covered. My 10" mak has a long dew shield - I have a foam "blanket" that I wrap around the dewshield - not pretty, but it usually works just fine for one to two hours. I hate to bring heat into the equation for high resolution imaging. Though I haven't seen it myself, I've heard stories of folks noticing the heat plume deformation in the image from a hand brought close to the incoming light.

best,

Alan