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Thursday, October 12, 2017

HDR Crepuscular rays

 I recently purchased the Aurora 2018 HDR software and have found it relatively easy to use with many presets tailored to many different types of imagery.  My most recent eclipse post on this blog shows another sample of its utility.  Here is a mid afternoon cloud shot taken from near the 4-meter telescope on Kitt Peak looking generally west-south-west-ward towards the southwest ridge of telescopes.  The scene greatly benefits from HDR techniques:

The first image is a combine of 5 images taken with my Sigma 17-70mm lens at 17mm focal length with exposures on the short end starting at 1/1250 seconds at f/8 and the longest at 1/200 seconds, all at ISO 100.  I used Aurora's "Realistic Bright" preset which brought out the landscape and helped also show the crepuscular rays coming down from the clouds.

This is the mid exposure (which is also the nominal exposure on this scene) of the 5 HDR images so you can see how dark the landscape is and also how washed out the details in the clouds appear.  The exposure was 1/500 seconds at f/8, ISO 100.

Sunday, October 01, 2017

Total Eclipse, take 2 on HDR combines...

I recently installed the Aurora 2018 HDR software on my PC and here are a couple different HDR combines which greatly enhance the detail in the solar corona as well as helping to bring out the detail in the Earthshine-lit lunar surface in some HDR exposed images of the August 21, 2017 total solar eclipse.  The HDR combines use 5 images taken at 2 stop intervals from 1/500 seconds to 1/2 seconds using my Canon 6D with a 0.7x focal reducer on my 8 inch EdgeHD telescope.  The images were taken about 25 seconds before the end of totality when the prominences on the western side of the Sun were mostly uncovered by the Moon.  Once I learn how to use Aurora, I might be dangerous in taking HDR images!

This first image combine is from 5 HDR frames taken at 2 stop intervals about 25 seconds before the end of the total phase of the August 21st total eclipse.  I wanted to show off the prominences on the western side of the sun as well. Not only is there lots of detail in the corona, but the Earthshine-lit lunar surface shows a great deal of detail.

This second image trades some corona brightness for some more detail on the view of the prominences but uses the same 5 images as the first image above.