From: "Tim" <tjp314@pacbell.net>

Date: September 26, 2005 11:20:24 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: M2 from Los Angeles - dew

Alan:

My setup is a little complicated.  We live on a hilltop, and though my "back yard" is kind of 

isolated from the outside world, where I set my scope up is visible.  So I prefer not leaving 

it unattended for any length of time.  I keep the C-8 in my basement shop, which stays 

pretty cool during the day, but is probably 10 degrees warmer than the outside air in the 

morning.  This scope can't see the eastern sky, though, because of the house.  So, as we 

overtake Mars and switch to "daylight wasting's time" toward Halloween, I think I'll move 

back to my other scope...

My other scope for planetary, the Nexstar 925, is in my roof, where I can leave it set up 

alone.  I close it off from the house with doors beneath the scope, but I haven't had the 

opportunity to be certain that thermals aren't still a problem.  Vibration is only a problem 

when my son and his friends are running up or down the stairs below!

Since both these scopes are SCTs, I'd be interested in hearing your thoughts about the 

Kendrick system and how it might affect planetary definition.  I'd prefer not to use a blow 

drier, also, but I'm not sure I'm ready to spend a few hundred bucks on the temperature 

controllable Kendrick system.   I could also try a dewshield, but the opening around my 

9.25" is so tight it might hit the sides if I slew too close to the horizon.

-Tim.

--- In Astro_IIDC@yahoogroups.com, Alan Friedman <alan@g...> wrote:

When I shoot Mars I usually set-up the evening before to let my scope 

cool completely. I leave it with caps on covered by a tarp and go to 

sleep, setting the alarm to get up for mars (somewhere between 2:00 and 

3:30 at the moment.) Things may have gotten dewy outside but the optics 

will be dry. If I am going to be up all night I always set up a 

Kendrick dew system. But for a couple of hours of imaging near dawn I 

wrap a layer of foam around my dewshield - this is will delay the 

formation of dew quite effectively.

Dew is a drag. It deposits airborne contaminants on the corrector which 

requires more frequent cleaning. I almost never use a hair dryer. 

Blasting warm air at the optics will generally ruin the figure of the 

glass for the balance of the observing session. At the end of the 

imaging session I cover the scope and put it away in the case (which 

has been left closed) and let the scope return to ambient temperature 

slowly.

Best -

Alan

On Sep 25, 2005, at 6:53 PM, Milton Aupperle wrote:

Hi Tim;

Very nice shot for a first time out doing DSO's with Astro IIDC.

I think you'll be impressed with the increased sensitivity your going 

to get with Mars imaging, as the larger pixels give you about 40% 

more light per pixel than the ApLux gathers. You can use less gain 

and/or run at higher frame rates, which will help improve S/N.

I can sympathize with the dew problems. When I was on holidays I 

tried imaging the day after it had finally stopped raining (3 days 

worth). The scopes optics would "dew up" after 5 minutes and the only 

way to briefly clean them was with the hair dryer at max. However to 

make matter worse, when I checked the optics with a flash light for 

how dewed they were, a bazillion little gnats and moths would land on 

the optics and get stuck there. After 45 minutes of screwing around I 

finally packed it in for the night. After another day of sunny 

conditions all the dew was gone and the dessert like climate in 

Saskatchewan allows me to image all night with none of those problems 

at all.

TTYL..

Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

#1005 - 815 14th Avenue. S.W.

Calgary Alberta Canada T2R0N5

1-(403)-229-9456

milton@o...

www.outcastsoft.com

On 25-Sep-05, at 10:17 AM, Tim wrote:

Folks:

I uploaded a file into the DSO area this morning.  It's a stack of 

ten 20" exposures taken with

my new Pt. Grey Flea camera (the camera is actuallly smaller than 

the Mogg 1 1/4" adapter

with the 0.6 FR lens).

I experimented for about 3 hours last night with various DSO 

objects.  I would have shot Mars

as well, but was set up in the back yard, and our house is 40' 

tall, so it didn't rise above the

roof before I started to fade!  Too bad, too.  The seeing was 

pretty good, though the dew was

moderate.  I don't have a dew heater, so I had to use a blow dryer 

every 20 minutes or so.  I

thought the clouds would roll in by morning, but they didn't.

Anyway, I am amazed at the quality of the images from the Flea.  

Dark frame subtraction in

Astro IIDC works very well, too.  If anything, I found that taking 

these sample DSO images

with the flea was orders of magnitude easier than my "first night 

out" with my Meade DSI Pro.

And the image quality is much better, too.

YAHOO! GROUPS LINKS

▪  Visit your group "Astro_IIDC" on the web.

 

▪  To unsubscribe from this group, send an email to:

 Astro_IIDC-unsubscribe@yahoogroups.com

 

â–ª  Your use of Yahoo! Groups is subject to the Yahoo! Terms of 

Service.