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Saturn w/6 Moons 2021-09-12

Planet Maksutov DSLR Astrophotography
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#1 BQ Octantis

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Posted 13 September 2021 - 05:11 AM

Seeing was meh last night. But Titan was in the sensor FOV at 2×…so I did what I had to…

 

(Click for full size.)

final.jpg

EP projection, Live View capture, 76% capture scale

 

Cheers,

 

BQ


Edited by BQ Octantis, 14 September 2021 - 01:19 AM.

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#2 Tim J Fowler

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Posted 13 September 2021 - 06:38 AM

…so I did what I had to…

Love it! Well done!

Tim



#3 matt_astro_tx

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Posted 13 September 2021 - 06:53 AM

Excellent, as always.

 

Could you explain what this is telling me?  Is it a measure of the seeing conditions or what?

Attached Thumbnails

  • Airy Pattern.PNG


#4 BQ Octantis

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Posted 14 September 2021 - 05:51 AM

Thanks Matt!

 

As to the spots, the one on the right is the easiest to explain: it is simply the pixel scale relative to angular reality. The circle is 1 arcsec in diameter. At this scale, that was 6.7 pixels:

 

arcsec.jpg

 

The one on the left is the scale of the aperture's performance limit in perfect seeing. The best reference we have for an aperture's best ability to produce detail is the Airy pattern, which is how a circular aperture spreads the light from a point source. It is wavelength-dependent:

 

Airy_disk_D65.jpg

 

Features in the image at that scale and smaller are below the aperture's point resolution. However, the detection limit for planetary features is ~10-15× smaller, depending on the contrast of the feature.

 

BQ


Edited by BQ Octantis, 14 September 2021 - 06:40 AM.

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#5 mayhem13

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Posted 14 September 2021 - 06:03 AM

Great explanation. Thanks BQ!



#6 matt_astro_tx

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Posted 14 September 2021 - 10:43 AM

Agreed.  Thanks for the splaining.




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