Mars 2025

[Trev S]

Attached is my attempt to image Mars a few weeks before its 2025 opposition. Mars is at its furthest orbital path this year, so it is quite a small subject not helped by the poor seeing and the overhead jetstream.  Captured at 23:00 on 7th January 2025 from my back garden in Surrey.

Celestron C9.25 with 2x Powermate giving f/20

SVBony 705C colour camera with IR cut filter

AZ-EQ6GT mount

Captured using SharpCap

Best 10% of 5000 frames at 1.5x drizzle

Processed with AutoStakkert v4 and Registax

Thanks for looking

[Casper Dyne]

Hi Trevor

The photo of Mars is brilliant, and I must say that I have made so many attempts with over exposure images. It is a difficult object to take and a well done to you! 

Astronomy is fun and a great hobby.

Casper

Sent from Outlook for iOS

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From: croydo...@googlegroups.com <croydo...@googlegroups.com> on behalf of Trev S <trevs...@gmail.com>
Sent: Wednesday, January 8, 2025 2:08:21 PM
To: croydonastro <croydo...@googlegroups.com>
Subject: [croydonastro - 8007] Mars 2025

 

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[tcos...@gmail.com]

Hi Trev

That’s a terrific image of Mars. I’ve seldom seen better! You’ve got both colour and detail plus the polar cap. Your C9.25 strikes again!

Well done

Tim C

 

From: croydo...@googlegroups.com <croydo...@googlegroups.com> On Behalf Of Trev S
Sent: 08 January 2025 14:08
To: croydonastro <croydo...@googlegroups.com>
Subject: [croydonastro - 8007] Mars 2025

 

Attached is my attempt to image Mars a few weeks before its 2025 opposition. Mars is at its furthest orbital path this year, so it is quite a small subject not helped by the poor seeing and the overhead jetstream.  Captured at 23:00 on 7th January 2025 from my back garden in Surrey.

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[drja...@aol.com]

Trev

It certainly is.  One of the clearest I've seen, despite Mars being small and with poor seeing!  The exposure time per frame must be relatively high too at f20.  

How is drizzling done for planetary targets?

James

Sent from my iPad

On 9 Jan 2025, at 17:46, tcos...@gmail.com wrote:



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[William Bottaci]

Hello Trevor
That's a pretty good image of Mars by any account; polar cap and distinct features; tracking must have been a challenge with the Powermate. Imagine how much better it would be by changing nothing on your side but to be fair it ought to be taken into account that this is not a favourable opposition, the latitude of the UK and the atmosphere, with the Jetstream to boot.
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On drizzling (and not wishing to take away from your very good result but a related subject, especially as you've used it :), I see how it works for deep sky objects as they tend to be under-sampled, but for planetary and with your equipment, typically they tend to be over-sampled. A calculation:

  Formula for pixel scale (arcseconds/pixel) = (Pixel size (microns) * 206.265) / Focal Length (mm).
Ideally with average seeing we want a value between 0.67” and 2” per pixel. The calculation with your data:
  - Celestron C9.25 focal length with 2x Powermate: 4,700 mm
  - SVBony 705C colour camera pixel size: 2.9 μm
we get a value of 0.13" per pixel, which is well over-sampled.

It's unfortunate that poor seeing makes the situation worse.
As your camera can bin to 2x2 at least this would be a suggestion, but the result shows the 2x Powermate is unnecessary, for imaging, and so not using it would be equivalent...
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Anyway, hoping the above is of help, and as said, a very good result, so thank you for sharing.
William

On Fri, 10 Jan 2025 at 07:57, 'drja...@aol.com' via croydonastro <croydo...@googlegroups.com> wrote:
Trev
It certainly is.  One of the clearest I've seen, despite Mars being small and with poor seeing!  The exposure time per frame must be relatively high too at f20.  
How is drizzling done for planetary targets?
James

On Thu, 9 Jan 2025 at 17:46, <tcos...@gmail.com> wrote:
Hi Trev
That’s a terrific image of Mars. I’ve seldom seen better! You’ve got both colour and detail plus the polar cap. Your C9.25 strikes again!
Well done
Tim C

On Thu, 9 Jan 2025 at 10:45, Casper Dyne <caspe...@hotmail.co.uk> wrote:
Hi Trevor
The photo of Mars is brilliant, and I must say that I have made so many attempts with over exposure images. It is a difficult object to take and a well done to you!
Astronomy is fun and a great hobby.
Casper