Lunar Eclipse For Night Owls

The Moon passes through the darkest part of the Earth’s shadow in the early morning hours of 19 Nov 2021. Normally, that would be called a total lunar eclipse. Not quite this time. About 3% of the Moon will not enter the umbra at 3:03 am. But, it will still be a worthy sight. This diagram from Sky & Telescope shows the details for the central time zone in the US. More information can be found at this S&T url.

I set my planetarium software to illustrate the eclipse. It starts at midnight and proceeds to 6 am. The video lasts 25 sec.

Astro Images | Ring Nebulae

Browsing the Hubble Legacy Archive, I was intrigued by a small ring shaped nebula NGC 6369. It is also known as the Little Ghost. Discovered by 18th century astronomer Sir William Herschel, it lies over 2000 lt-yrs away in the constellation Ophiucus. The sun-like star at the center explosively blasted away its outer layers creating the ring of glowing gases. The star radiates strongly in ultraviolet causing the glow of the nebula. The blast also reduced the star to a white dwarf. For this color image, I combined three blue, green, and red filtered grey-scale Hubble images. The colors illustrate the presence of ionized oxygen, hydrogen, and nitrogen atoms.

NGC6369 | Hubble Legacy Archive | My Version

Fellow amateur astronomer Roger captured an image of his own recently of a different ring-shaped nebula NGC 7293 in his southern hemisphere sky. It is published here in his blog Cosmic Focus.

Astronomy fans are likely familiar with Messier 57 high in the summer sky of the northern hemisphere. It is another fine example of a ring nebula. Follow the link for a beautiful image and description.

Mississippi River Lock & Dam 15

In 2016, we traveled to Scotland. A highlight of our trip was the week-long barge journey from Inverness to Banavie. It followed the route of the Caledonian Canal allowing us to traverse Lochs Dochfour, Ness, Lochy, and Oich from the North Sea to the Atlantic side of Scotland. The canal was finished in 1822. A fascinating part of the canal is the system of 29 locks used to raise and lower boats. The highest elevation reached is 106 ft above sea level. Our post is here about the lock system. Pictured below is one of the sets of lock gates viewed with Google Maps. The water level in the upper right is higher than at the lower left.

Last week, my friend David and I traveled to the Mississippi River at the Quad Cities to do a boat tour of Lock & Dam 15 conducted by two engineers with the U.S. Army Corps of Engineers. They explained much of the history of the river and early attempts to navigate boats through this region. They also described the maintenance of the dam and locks to further their useful life. They also discussed some of the history of the Rock Island Arsenal as we passed by.

The multiple gates of the dam are on the left in the next image. They control the river flow from upper right to lower left. There are two locks for river traffic just right of center. Our tour boat passed through the smaller of the two locks. Large tugboats and their barges pass through the larger lock.

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Ingenuity Flights | Enhanced Views

See flights 2 and 3 at the end of this post.

The first video view of the flight of the Ingenuity helicopter on Mars was short and jerky. It lasted 13 sec. The initial video data omitted many frames in order to quickly confirm for scientists that the flight was successful. Since that time, the rest of the frames have been downloaded and compiled into this version of 57 sec. The camera used was on the Perseverance rover several meters away.

Things to watch for include spin-up of the rotors at 7 sec. Liftoff takes place at 15 sec. It reaches 3 meter altitude at 19 sec. It hovers and does a 90˚ turn at 24 sec. It holds that position for several seconds. During that time, notice how it drifts to the right and then left a little bit. The gentle Martian breeze that day caused the drift. Ingenuity regained its position correctly. It started to descend at 37 sec with touchdown 3 sec later.

Scientists at JPL used special video filtering to capture the faint dust cloud stirred up by the rotors of the helicopter.

“The Mastcam-Z imager aboard NASA’s Perseverance Mars rover shot video of the helicopter’s flight. The video is presented here in side-by-side formats that have both been enhanced to show a dust plume swirling during takeoff and again on landing. The view on the left uses motion filtering to show where dust was detected during liftoff and landing and the view on the right is enhanced with the motion filtering. Scientists use this image processing to detect dust devils as they pass by Mars rovers.”

While Ingenuity hovered, the camera on the bottom aimed straight down captured this image of its shadow. Imagine looking straight down from the height of a basketball hoop. The fast shutter speed froze the positions of the two counter-rotating rotor blades spinning at about 2500 rpm. The 4 legs of the copter are visible.

UPDATE: Flight 2 and images taken by Ingenuity in this video.

UPDATE: Flight 3 starts at the lower left. Lift-off at 10 sec. Cruises off screen to the right. Returns to view at 49 sec and then to touchdown.

Perseverance Rover

Much of the excitement has settled now that Mars 2020 Perseverance Rover is safely on the surface of Mars after the 18 Feb 2021 landing. I gathered images and links to a collection of things I feel tell the story of this rover in a not too complicated way. The mission is very challenging. A primary goal is to find evidence that microbial life may have existed on the Martian surface in the past.

Perseverance is undergoing system checks for the many sophisticated tools it carries while imaging the surroundings. Scientists are eager to begin moving the rover across the ground and to test the helicopter Ingenuity it carried under the chassis.


Touchdown in Jezero Crater

You might wonder where Perseverance landed and why is that place is important. Landing took place in Jezero Crater. The crater is about 49 km (30 mi) across. It is believed to have once been filled with water. This image shows a dried riverbed and delta of a water source that once flowed left-to-right and filled the crater. The colors are indicators of various types of mineral deposits and not actual colors. The rover landed in the lower right quadrant of this image just below the two side-by-side small craters on the flat plain and not far from the delta formation.

Ancient river delta into Jezero Crater | MRO | NASA

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