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

Ultima Thule | Best View by New Horizons

The New Horizons spacecraft returned this detailed image of Ultima Thule to Earth on 18-19 Jan 2018. It was captured 7 minutes before the closest approach to Ultima Thule at a distance of 4,200 mi (6,700 km). The signal of digital bits traveled at the speed of light for 6 hrs before reaching the antenna at Earth so we could see it.


The shape of Ultima Thule was discovered in July 2017 when it passed in front of a distant star as seen from Earth. Twenty four telescopes were lined up across Argentina where the shadow of Ultima Thule was to pass as it occulted the distant star. The scopes were coordinated with precise time markers. The best-fit of their timings suggested a bi-lobed object. What an amazing prediction considering UT is only about 20 mi (30 km) across and measured from more than 4 billion miles away.

This is probably the oldest and most primordial object we will ever see in such detail.

Ultima Thule belongs to a class of Kuiper belt objects called the “Cold Classicals,” which have nearly circular orbits with low inclinations to the solar plane, and which have not been perturbed since their formation perhaps 4.6 billion years ago. Ultima Thule will therefore be the most primitive planetary object yet explored, and will reveal to us what conditions were like in this distant part of the solar system as it condensed from the solar nebula.


What’s next for New Horizons? Hopes are high for extensions to the mission into 2019 and beyond. It will take into 2020 to download all the data stored in the memory banks. With remaining fuel, New Horizons might survey the field ahead and redirect slightly to pass by other Kuiper Belt objects. Stay tuned to see what might happen.

Ships Passing in the Night

It was 6:30 pm on 24 Jan 2018. The International Space Station was due to pass directly over our part of Iowa from WSW to NE. It was 3˚F outside with more than a foot of snow on the ground. Instead of going outside, I set the iPad in the bedroom window, closed the door, and recorded the pass for 6 minutes. While I watched the spaceship cruise above the trees at 5 mi/sec, an airship also cruised over at about 0.2 mi/sec. The stars silently observed from their perches. I stayed warm.

NightCap Camera | iPad2 | ISO=1536 | 356 sec | Click to embiggen

Ceres | My First Views

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

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.

Show me more…

New Horizons | Ultima Thule Flyby | 31 Dec 2018

The New Horizons spacecraft was launched in January 2006. It coasted by Pluto 14 July 2015 giving us our first close views of the dwarf planet and its moons. Previous posts highlighting events of the mission are found here.

After that flyby of Pluto, the mission gained a new challenge. It is headed for a flyby of a Kuiper Belt object called Ultima Thule. The flyby occurs late on New Year’s Eve about 11:30 pm CST. The closest approach distance will be about 2200 mi (3540 km) which is 1/3 the distance it was in the flyby of Pluto. I invite you to read remarks by Principal Investigator Alan Stern as New Horizons makes its final approach. Quoting Stern:

“What will Ultima reveal? No one knows. To me, that is what’s most exciting—this is pure exploration and fundamental science!”

From the New Horizons web site:

We will only know what Ultima Thule’s surface looks like once New Horizons has sent back the first pictures after it has flown by, although based on observations of similar-sized Solar System objects, it will almost certainly display impact craters. The lighting environment at its surface is very dim, as it receives only about 0.05% of the light from the Sun that Earth does. We do know that Ultima Thule has a reddish color, probably caused by exposure of hydrocarbons to sunlight over billions of years. The flyby will also reveal whether it has any moons, or even a ring system. Ultima Thule belongs to a class of Kuiper belt objects called the “cold classicals”, which have nearly circular orbits with low inclinations to the solar plane, and which have not been perturbed since their formation perhaps 4.6 billion years ago. Ultima Thule will therefore be the most primitive planetary object yet explored, and will reveal to us what conditions were like in this distant part of the Solar System as it condensed from the solar nebula.

I will be monitoring the progress of New Horizons at this site for the latest update news and images.

Christmas Morning | ISS Lunar Transit

Passes of the International Space Station are very predictable. There are internet sites that will email you notification of a coming pass. This one by NASA is easy to use. I use a site called CalSky which also notifies me if the ISS is going to pass in front of the Sun or Moon for my location. These transits are brief lasting barely more than a second. I’ve written about seeing several transits of the Sun in these posts.

Transits of the Moon are more difficult to see. The CalSky site has notified me fewer times about lunar transits. When they do occur for my location, the weather is sometimes a problem. This Christmas morning a transit was to occur but the forecast called for very cloudy skies. I woke not expecting to see it. When I looked out the window, the Moon was shining brightly in a clear patch of sky. I got my camera ready and hoped it would stay clear. It did just barely long enough. Here are three frame-grabs from the video showing the ISS just before, during, and after the transit.

This is the video slowed down to 50% speed. It is best viewed on a large screen with quality set to HD. It is not likely visible on a phone or tablet screen. The transit begins at the 7 o’clock position and ends at the 2 o’clock position of the Moon’s face. It lasts only 2.5 sec on this video, only 1.24 sec in real time.

I’ve waited a long time to see this. It was great to have it occur on Christmas morning. What a nice present.

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.

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.