Better view of Double Cluster


Howard Ritter
 

I was unhappy with the way my image of the Double Cluster turned out in the group post after being massaged by various email clients and systems. Lesson learned!

Here’s a much better rendering of it: https://www.astrobin.com/sfhvw0/

A not-unrelated question: What’s the best way to prevent dewing on the objective lens? At the end of this session, I was seeing small amounts of condensation on both the outer and inner surfaces of my 155EDF's objective. Will a heating strap around the tube at the level of the lens cell be effective w/o generating tube currents or other distortion?

—howard


M Hambrick
 

Hi Howard

The Kendrick Dew Heaters work great. They have been around for many years, and Astro-Physics sells them on their website. The new versions have a smart controller that allows you to set the temperature differential above ambient.

Mike


Luca Marinelli
 

I use Kendrick heaters as well and they are excellent indeed. I have the Kendrick controller but these days I just use the Pegasus Ultimate Power Box to control dew heaters, 12V power distribution, USB, and focuser motor.

 

Luca

 

 

From: main@ap-ug.groups.io <main@ap-ug.groups.io> On Behalf Of M Hambrick via groups.io
Sent: Thursday, September 22, 2022 6:05 AM
To: main@ap-ug.groups.io
Subject: Re: [ap-ug] Better view of Double Cluster

 

Hi Howard

The Kendrick Dew Heaters work great. They have been around for many years, and Astro-Physics sells them on their website. The new versions have a smart controller that allows you to set the temperature differential above ambient.

Mike


Roland Christen
 


Will a heating strap around the tube at the level of the lens cell be effective w/o generating tube currents or other distortion?
Yes indeed. Wrap it around the bottom of the dewcap.

Rolando

-----Original Message-----
From: Howard Ritter via groups.io <howard.ritter@...>
To: main@ap-ug.groups.io
Sent: Wed, Sep 21, 2022 10:50 pm
Subject: [ap-ug] Better view of Double Cluster

I was unhappy with the way my image of the Double Cluster turned out in the group post after being massaged by various email clients and systems. Lesson learned!

Here’s a much better rendering of it: https://www.astrobin.com/sfhvw0/

A not-unrelated question: What’s the best way to prevent dewing on the objective lens? At the end of this session, I was seeing small amounts of condensation on both the outer and inner surfaces of my 155EDF's objective. Will a heating strap around the tube at the level of the lens cell be effective w/o generating tube currents or other distortion?

—howard


Howard Ritter
 

Thanks, Roland. Several others recommending the same from experience. 


—howard

On Sep 22, 2022, at 11:21 AM, Roland Christen via groups.io <chris1011@...> wrote:


Will a heating strap around the tube at the level of the lens cell be effective w/o generating tube currents or other distortion?
Yes indeed. Wrap it around the bottom of the dewcap.

Rolando

-----Original Message-----
From: Howard Ritter via groups.io <howard.ritter@...>
To: main@ap-ug.groups.io
Sent: Wed, Sep 21, 2022 10:50 pm
Subject: [ap-ug] Better view of Double Cluster

I was unhappy with the way my image of the Double Cluster turned out in the group post after being massaged by various email clients and systems. Lesson learned!

Here’s a much better rendering of it: https://www.astrobin.com/sfhvw0/

A not-unrelated question: What’s the best way to prevent dewing on the objective lens? At the end of this session, I was seeing small amounts of condensation on both the outer and inner surfaces of my 155EDF's objective. Will a heating strap around the tube at the level of the lens cell be effective w/o generating tube currents or other distortion?

—howard


Karen Christen
 

It’s kind of amazing how much nicer these images present when not compressed by the groups.io algorithm.  Groups.io is great and has served us well, but not for astro-photos.  Nice double cluster, Howard.

Karen

AP

 

From: main@ap-ug.groups.io <main@ap-ug.groups.io> On Behalf Of Howard Ritter via groups.io
Sent: Wednesday, September 21, 2022 10:50 PM
To: main@ap-ug.groups.io
Subject: [ap-ug] Better view of Double Cluster

 

I was unhappy with the way my image of the Double Cluster turned out in the group post after being massaged by various email clients and systems. Lesson learned!

 

Here’s a much better rendering of it: https://www.astrobin.com/sfhvw0/

 

A not-unrelated question: What’s the best way to prevent dewing on the objective lens? At the end of this session, I was seeing small amounts of condensation on both the outer and inner surfaces of my 155EDF's objective. Will a heating strap around the tube at the level of the lens cell be effective w/o generating tube currents or other distortion?

 

—howard


M Hambrick
 

HI again Howard

We have very high (>90%) humidity here in Southeast Texas with heavy dew, so, I have always set my heaters at a constant output of 70%. I can't remember when it was, but there was a similar discussion about dew heaters a couple years ago, and I think Roland might have mentioned that he set a constant output for the dew heaters on his refractors.

I have never actually used the Delta-T functionality of the Kendrick heaters, but I recall from the instructions that they recommend starting low, between 2 and 4 Deg C differential and working up if necessary.

Mike


Howard Ritter
 

Thanks, Mike. I have a Dew Not on order. It’s a couple of inches short of full measured circumference, but the next larger size was out of stock everywhere I looked. I’m hoping the discrepancy won’t be noticed by Dick Dew, or later by Jack Frost.

—howard


On Sep 23, 2022, at 11:55 PM, M Hambrick <mhambrick563@...> wrote:

HI again Howard

We have very high (>90%) humidity here in Southeast Texas with heavy dew, so, I have always set my heaters at a constant output of 70%. I can't remember when it was, but there was a similar discussion about dew heaters a couple years ago, and I think Roland might have mentioned that he set a constant output for the dew heaters on his refractors.

I have never actually used the Delta-T functionality of the Kendrick heaters, but I recall from the instructions that they recommend starting low, between 2 and 4 Deg C differential and working up if necessary.

Mike