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Sunrise on Gassendi and a Bonus(?)

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#1 james7ca

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Posted 14 July 2019 - 11:49 AM

Taken on July 12 at just before 11PM PDT using a Celestron 9.25" EdgeHD (f/10) and a ZWO ASI178MM camera.

 

Capture done with Sharp Cap Pro, image processing with AutoStakkert! (best 20% of 6000 images), Registax, and Photoshop CC2019.

 

Also, the NASA Visualization image showing the simulated lunar terminator (about five minutes later than my image).

Attached Thumbnails

  • Sunrise on Gassendi and Mare Humorum (Crop).jpg
  • NASA Visualization July 13 2019 6-00UTC.jpg

Edited by james7ca, 14 July 2019 - 12:15 PM.

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#2 james7ca

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Posted 14 July 2019 - 12:00 PM

Here is a cylindrical projection of my image using WinJUPOS. This approximates what these features would look like without the foreshortening caused by our viewing location on earth.

 

I think I can do a little better version of this and thanks to user aeroman4907 for posting his earlier versions of lunar images processed with WinJUPOS.

Attached Thumbnails

  • Gassendi Cylindrical Projection with WINJUPOS.jpg

Edited by james7ca, 14 July 2019 - 12:16 PM.

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#3 james7ca

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Posted 14 July 2019 - 12:12 PM

And, finally, the "bonus" (or was that the projection?). Jupiter with the above equipment, taken on the same evening. I had to use a manual filter drawer and refocus between each filter so my capture sequences were limited to 3000 frames for each red, green, and blue filter change. However, I de-rotated the channels using WinJUPOS and then combined another sequence that I did about 15 minutes later. Jupiter's altitude was just over 30 degrees (about 1.5 hours after transit).

Attached Thumbnails

  • Jupiter with EdgeHD and ASI178MM.jpg

Edited by james7ca, 15 July 2019 - 02:02 AM.

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#4 Tom Glenn

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Posted 14 July 2019 - 05:36 PM

Nice images, James.  For your Winjupos projection, how did you align the reference frame unless you had an image containing the entire lunar disk?  In the absence of a full lunar disk image, I suppose you could superimpose your image panel onto an appropriately scaled simulation from the NASA libration page, and then align that to the reference in WInjupos?  I bet there is some considerable leeway for error in the alignment that would really only be noticeable if you spot-check the latitude and longitude coordinates in your resulting map to LRO data.  Otherwise, mistakes in the projection would probably be impossible to notice, and your version looks good.  



#5 james7ca

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Posted 14 July 2019 - 10:46 PM

Nice images, James.  For your Winjupos projection, how did you align the reference frame unless you had an image containing the entire lunar disk?  In the absence of a full lunar disk image, I suppose you could superimpose your image panel onto an appropriately scaled simulation from the NASA libration page, and then align that to the reference in WInjupos?  I bet there is some considerable leeway for error in the alignment that would really only be noticeable if you spot-check the latitude and longitude coordinates in your resulting map to LRO data.  Otherwise, mistakes in the projection would probably be impossible to notice, and your version looks good.  

Yes, I just scaled and rotated the full-disk output from the NASA Visualization service and then overlayed my image onto that. I used Photoshop to do the overlay with my image and it was fairly quick to do (looking at the difference blend). I think the final overlay was within a few pixels (better in some places, with combined error, rotation and horizontal and vertical translation). I measured the rotation and scale just once, then did the rotation and then the scaling (the latter took a while, since it produced a 50M pixel image). I also tweaked the rotation (by about 0.2 degrees) just before the rescaling to better match my original measurements in Photoshop.

 

Of course, this also means you can do this kind of projection mapping on practically any lunar image, no matter how small the field (although you are somewhat limited by the 16000 pixel-wide output from WinJUPOS, however, I think there may be a way around the latter). Also, the NASA simulation includes the position angle of the moon's north pole, so you can accurately adjust the rotation to keep north directly up (the angle was 7.9 degrees on the night that I took my image). The NASA simulations appear to go back to 2011, so lots of potential to match past images.

 

Below is the final overlay (reduced greatly in size to conform to the CN limits), with my shot of Gassendi on the lower left (showing up as grayscale against the color of the NASA simulation). This was then imported into WinJUPOS to produce the projection map. Following that, I went back to Photoshop with the image map produced by WinJUPOS and rotated and cropped out everything but my original image. One further thing that could be added is to use the color information from the NASA simulation to colorize a mono image. I'll have to see how that works, although that would mean combining my own data with that from NASA which seems a little bit of a "cheat."

Attached Thumbnails

  • Gassendi NASA Overlay.jpg

Edited by james7ca, 14 July 2019 - 11:16 PM.

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#6 Tom Glenn

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Posted 15 July 2019 - 02:59 AM

That NASA libration simulator has indeed proven to be one of the most useful Moon tools on the web, for a variety of purposes.  And it's no small feat either to generate that simulation.  Although the rendering looks photographic, and the shadows are 100% accurate, there obviously doesn't exist a photograph of the Moon at every possible instant, and so everything is generated using the calculated altitude and azimuth of the Sun over the lunar surface at a given point in time, and predicting the appearance of shadows based upon topography data from the LRO.  Really an amazing resource.  



#7 aeroman4907

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Posted 15 July 2019 - 07:03 AM

Nice work James.  Thanks for the shout out as well!

 

 

Of course, this also means you can do this kind of projection mapping on practically any lunar image, no matter how small the field (although you are somewhat limited by the 16000 pixel-wide output from WinJUPOS, however, I think there may be a way around the latter).

If you find a way to crack the 16000 pixel wide limit, I'd be interested in hearing how you do that if you don't mind.  There's nothing like a large projection to try and break a program or computer!




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