Dial-a-Moon | 2019

How will the Moon look on any date in 2019? What will it look like on your birthday? Find out at NASA Dial-a-Moon. Here is Dial-a-Moon for southern hemisphere readers.

8 Feb 2019

Enter any month and day to see a high definition image. The composite images of Dial-a-Moon are made from those of the Lunar Reconnaissance Orbiter (LRO) in low altitude orbit around the Moon since 2009.

You may leave the universal time (UT) at the default value. Your local to Universal time conversion can be done at this link. Or, type ‘universal time’ into Google. Go back to Dial-a-Moon to enter the UT.

A Year of Moon Motions

The collection of accurate images of the Moon for each hour have been made into the movies below each lasting about 5 minutes. Try watching full screen for the best effect. Versions of the movie are available for readers in the northern and the southern hemispheres.

I explain the Moon’s peculiar wobble and tipping motions at this blog post.

Northern hemisphere

Southern hemisphere

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Fireballs Across the Sky

My great-grandparents were married in 1870. They farmed in west-central Illinois a mile from his brother. The brothers moved to Illinois from Ohio. Earlier, they moved to Ohio from Virginia during the Civil War. The rectangle in this 1941 aerial photo shows the location of the farmstead where my great-grandparents lived after they were married.

1941

Here are my great-grandparents and their five children in about 1890. My grandfather is the one in the center back row.

Here is my great-grandfather’s brother and his wife. They eventually had seven children. Notice a date of Oct 74 at the bottom. That is when a relative photographed the original photo from nearly 100 years before.

 

Ceres | My First Views

Update: Second date of views (4 Jan 2019) is at the bottom of this post.

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The largest asteroid Ceres has been orbited by the ion-engine powered DAWN spacecraft since early 2015. DAWN ran out of fuel to maneuver in October 2018 and will remain silent in orbit at Ceres for decades. Previous to Ceres, it visited the second largest asteroid Vesta. This fly-over video gives a close view of Ceres.

The asteroid is far away and quite small and dim. It is not something most people have ever seen with the naked eye or in a telescope. I’ve been tracking Ceres with desktop planetarium software with hopes to see it. I am happy to report success.

I Made It to Mars

UPDATE: InSight landed successfully on Mars on 26 Nov 2018. The microchip with my name and 2.4 million others is now resting on Mars attached to the spacecraft.

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6 Nov 2017: My bags are packed. I am ready to join 2.4 million other passengers as we begin our journey to Mars in May 2018 aboard the INSIGHT spacecraft. The trip will take about 7 months. It is a one-way journey.

Click to read the fine print. My flight miles award will be enormous.

INSIGHT is the acronym for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. NASA loves acronyms. Previous Mars missions have studied intensively the surface and atmosphere of the planet. This spacecraft is the first designed to study the interior in hopes of finding clues to the formation of the rocky inner planets. The spacecraft will use seismology, heat flow equipment, and very precise tracking to probe the planet below ground.

InSight Lands Safely on Mars

I love to see scientists celebrate success of their work. Today the InSight spacecraft made a safe landing on the surface of Mars. It was a tense 7 minutes. The video has been set to begin moments before touchdown. Watch and enjoy.

ISS Passed by Saturn and Mars

The International Space Station approached from the northwest at 9 pm on 8 Aug 2018. It went high overhead in a southeasterly direction. It tracked above Saturn and the Teapot in Sagittarius before disappearing near Mars. There it entered the darkness of Earth’s shadow.

Taken on iPad with NightCap | ISS mode | 189 sec exp

Here is the same image annotated. Can you also see the light trails left by two passing jets? Tap images for more detailed views.

Looking SE at 9 pm

Return From Space

Discussion in a previous post centered on getting to space and into an orbit near Earth. This post is about how spacecraft return from orbit. Some returns are under control and some are not.

Energy Exchange

Launch to orbit requires giving a spacecraft a large amount of kinetic energy of motion (KE) and a large amount of gravitational energy (PE) due to its altitude. The large amount of work done to gain those energies comes from the potential energy released by an engine(s) as fuel burns. Once in orbit with engine(s) off, the total of those two energies (KE+PE) stays constant except for the small decrease due to the small atmospheric drag at high altitudes. If the orbit is a circle the two energy quantities are unchanging.

If the orbit is an eccentric ellipse, the quantities do change but not their total. The next graphic shows an eccentric orbit of an Earth satellite. When it passes closest to Earth (perigee), the KE is at its maximum value and the PE is at its minimum. Font size was changed to illustrate their inequality. When at its farthest point in orbit (apogee), it is going slowest with minimum KE and is at its highest altitude with maximum PE.