Owl cluster

[Kevin Phillips]

Due to the moon being full out I decided to capture the Owl cluster 7,900 light years from earth in consultation of Cassiopiea NGC457. 60 lights and calbration frames. 

Process in Startools. Had a number of issues with guiding but resolved that one. Also had a weird experience with the calbration stars. The first star the handset choosed was Actarus, but scope was so far away could not figure out what was going on.  the next night same thing way, way off. So I decided to choose a different star, I went to Vega, it slew there and it was pretty much bang on target , the second star bang on target and its third star was Actarus and that too was on target. 

Apparently someone else had the same issue and they could not figure out what was going on. I guess its a mystery I will never know. 

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[paul stenning]

Hi Kevin ,i like this one when did you take it and what equipment did you use.

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[Kevin Phillips]

Thank you. I capture the owl cluster on Thursday night last week.

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From: Kevin Phillips <thewels...@live.com>
Sent: Monday, August 15, 2022 1:49:21 PM
To: croydo...@googlegroups.com <croydo...@googlegroups.com>
Subject: Re: [croydonastro - 7385] Owl cluster

 

I used eq5 mount on a pillar. ZwoISA294 osc, guided. 

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From: croydo...@googlegroups.com <croydo...@googlegroups.com> on behalf of paul stenning <paulste...@gmail.com>
Sent: Monday, August 15, 2022 1:43:17 PM
To: croydo...@googlegroups.com <croydo...@googlegroups.com>
Subject: Re: [croydonastro - 7385] Owl cluster

 

To view this discussion on the web visit https://groups.google.com/d/msgid/croydonastro/CAFmvboO%3DzN0Q8t17W841UYX0FG261zirFmhrj_0BHiS2WUHacg%40mail.gmail.com.

[Kevin Phillips]

I used eq5 mount on a pillar. ZwoISA294 osc, guided. 

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From: croydo...@googlegroups.com <croydo...@googlegroups.com> on behalf of paul stenning <paulste...@gmail.com>
Sent: Monday, August 15, 2022 1:43:17 PM
To: croydo...@googlegroups.com <croydo...@googlegroups.com>
Subject: Re: [croydonastro - 7385] Owl cluster

 

To view this discussion on the web visit https://groups.google.com/d/msgid/croydonastro/CAFmvboO%3DzN0Q8t17W841UYX0FG261zirFmhrj_0BHiS2WUHacg%40mail.gmail.com.

[William Bottaci]

Hello Kevin, this has come out well, and clearly a cluster amongst the background stars. You actually saw this a few days ago at Kenley, through the 15 x 50 binoculars as we were sweeping about; it was one of the several clusters in the area.
I assume it gets it's name because of two bright stars close together at one end, or I should say near the 'top'.
In Cassiopeia, about the same distance as the double cluster and Trevor's recent Heart Nebula.
The are some red stars recorded, at least stars we call red but really look orange, but some of that will be because stars tend to be over-exposed due to their concentrated brightness and limitations of imaging (not your limitations :).

Paul, the equipment used is a 900 mm f/9 (4-inch) refractor and the cooled one shot colour camera (OSC) has 4.63µm pixels. Many exposures stacked into one. The telescope camera combination has the measurements in the attached 'boilerplate'.

The resolution of 1.06 arcsecs per pixel is useful to know and was one of the criteria in choosing this camera. Relates to what is known as sampling; which is a measure of how large the typical small star relates to the pixels on the sensor. To be optimal the star needs to be between 1 to 2 pixels in size (the range varies by opinion and atmospheric turbulence). Large pixels means the star shines only on a part and so is inefficient or can miss the actual photodiode. Small pixels means that it shines over many and affects resolution, noise and sensitivity as it dilutes the light.
There's a simple formula (simple to use, once all the maths has been dealt with in deriving the equation) and basically depends on the focal length.

Thank you for sharing.
William

=C100EDR-F9_ASI294CPro_FoV.jpg (50K)=

On Mon, 15 Aug 2022 at 14:17, Kevin Phillips <thewels...@live.com> wrote:
I used eq5 mount on a pillar. ZwoISA294 osc, guided.

On Mon, 15 Aug 2022 at 14:16, Kevin Phillips <thewels...@live.com> wrote:
Thank you. I capture the owl cluster on Thursday night last week.

On Mon, 15 Aug 2022 at 13:43, paul stenning <paulste...@gmail.com> wrote:
Hi Kevin ,i like this one when did you take it and what equipment did you use.



On Mon, 15 Aug 2022 at 12:03, Kevin Phillips <thewels...@live.com> wrote: