Friday, July 8, 2022

Tau Herculid Meteor Storm, May 30, 2022

While I can't confirm that the Tau Herculid meteor storm delivered as a storm, I think it qualified as a shower, and as good as any I've seen or probably will see from my backyard balcony since the LED lighting revolution.

The meteors were notably slow and dim. Since I was pointing my camera near the radiant (apparent origin in the sky), the trails appear short because I'm looking at their paths head on. I also over saturated the color in the meteor images. The colors in the meteors, and the changes of color, confirm that these are burning light sources rather than reflected light sources from satellites. (I'm seeing more and more stock meteor photos that really are satellites, not meteors.)

Tuesday, May 17, 2022

Lunar Eclipse, 15 May 2022

 After reviewing a hundred nearly identical images I took during the May 15 lunar eclipse, I decided none cleaned up better than this 5-second exposure:

This image was taken with a 3-inch APO refractor at F5, 100 ISO and cropped to 1920x1280 pixels. The mount is a Losmandy G-11 and I used its lunar tracking rate. I believe the tracking rate made a difference in quality of fine detail, because I see motion blur in the background stars that is consistent across many images. If not for the lunar tracking rate, the motion blur would be in the moon image. The motion blur of the stars is detectable in my 5-second exposure but obvious in this 15-second exposure:

I've been seeing a number of eclipse composites, where the images of the entire eclipse event are superimposed on a scene. Most bother me, for the scale looks wrong. I prefer that composites be an honest depiction of scale and motion, or contain a caveat.

Here's the eclipse with a 28mm lens.

This shows the size of the moon against the roof line of a two story house about 60 feet away. 

A half hour earlier, the moon was in the trees:

The distance the moon travels between my wide-field images and it's apparent size are hard to squeeze into these composites from other sources: 


Saturday, March 12, 2022

Circum-zenithal arc in Taurus from a 5-day crescent moon

This is one my most unusual images. I caught a circum-zenithal arc while taking a picture of the constellation Taurus:

This image was taken with a 50 mm lens, which has a field of view barely able to fit the arc.

For comparison, here is a circum-zenithal arc in front of my home:

Until my Taurus arc, all images of circum-zenithal arcs I've seen are in daylight with the sun as the light source.  I included my house when I took the photo so I could use it to identify the zenith.

Here's my attempt to position Taurus in the same setting:

This photo was taken a week after the arc and I wasn't diligent about the time, but I hope it shows that Taurus is well-positioned to host a circum-zenithal arc at dusk in early February.

Here, I rotated the arc photo to match the orientation of my wide-field Taurus image. The arrow shows the direction of the 5 day crescent moon that was present at the time I took the photo.

For additional verification that this is a circum-zenithal arc, and not the more common 22-degree halo, here is a view of my location and time when I took the image: