My photo of a three day moon. East is at the bottom. Mare Crisium is the egg-shaped feature on east limb.

Here's my photo of a five-six day moon, near first quarter. East is at bottom here too. The middle [...]]]>

Lunar Landing Site Chart - click for larger versions. Courtesy Lunar and Planetary Institute

My photo of a three day moon. East is at the bottom. Mare Crisium is the egg-shaped feature on east limb.

Here's my photo of a five-six day moon, near first quarter. East is at bottom here too. The middle sea visible above/West of Mare Crisium is the Sea of Tranquility, site of the Apollo 11 landing.

Here's my photo of a fourteen day or full moon. East is at the top. Notice the features are less distinct, but look for the long rays spreading out from the two large craters Copernicus (lower middle left) and Tycho (lower right).

Finally, my photo of a 21 day or third quarter moon. West is at the bottom left

Fasten your seat belts. I’m going to take you on a guided month-long tour of the moon and highlight some of my favorite lunar features. You can use this travelog all year to observe or sketch the moon any time the moon is visible. You’ll be surprised how some of the familiar geology you’ll see on our rocky neighbor changes as sunrise or sunset illuminates different sides of crater walls. If you don’t have a moon map, click on the one to the left, or the other one at the bottom.

The visible features I describe will be illuminated by sunlight from the right to the left as shown on this moon chart. It takes 14 days from new to full moon. At full moon the entire disk will be illuminated, then sunset darkens the features night by night, from right to left. Try viewing the same features before, during and after the full moon.

New Moon Phase Day 1 – 6 The moon rises at dawn, and sets at dusk. The new moon phase starts at solar conjunction. This is the starting point of the lunation or period of the Moon’s cycle around the sky. Day 1 is very difficult to observe. On day 2, the “sea” of Crises, Mare Crisium becomes visible. To the south is Petavius, a large crater with a central peak of over 8000 feet. Day 3 brings Mare Fecunditatis, south of Mare Crisium, into view. On day 4, Mare Crisium and Mare Fecunditatis are fully visible, and the walled plain Janssen is visible. On day 5, Theophilus, Cyrillus and Catharina make a nice group of craters. The crater Maurolycus, with a central peak like Theophilus, appears on day 6. The moon is now approaching first quarter. The terminator (boundary between the sunlit and dark parts of the moon) is now at the center of the moon’s disk.

First Quarter Phase Day 7 – 13 The moon rises at noon, and sets at midnight. The crater Hipparchus is at its visible best near the terminator on day 7. Look for two craters within Hipparchus. Day 8 brings into view the rugged Appenine mountains, and to the north the oval walled plain Plato. With binoculars or telescopes, find the “Straight Wall”, a lunar fault line. Tycho and Copernicus are on the terminator on day 9, and so is Clavius, the large walled plain south of Tycho. On day 10 look for the Jura Mountains and Sinus Iridum (the bay of rainbows) with its hook-like curved mountainous point on the edge of Mare Imbrium. This is one of my favorite objects on the moon to observe and sketch. On day 11, look back on the whole moon and observe the dark lunar lava plains divided by mountains. On day 12, look at Gassendi, a large crater with a smaller crater next to it. Together they look like a diamond ring. As full moon approaches, look back over the objects you observed each night and see how different they look.

Full Moon Phase Day 14 – 21 The moon rises rises at dusk, and sets at dawn. Look at the bright ray systems. The direct sunlight on the moon at this phase washes out features, and you see no shadows, just like when the sun is directly overhead on earth. The long rays of Tycho are most dramatic at full moon! Day 15 brings sunset to Crisium, 2 weeks after we first viewed its sunrise. Watch the shadows cast on the walls of the plains including the darkened Mare Crisium, and craters on day 16 through 18. Day 19 is a good one to view the “Sea” of Tranquility, famous as the landing site of Apollo 11. There is a link to lunar landing sites at the bottom of the page, by the way. Day 20 brings the terminator to another of my favorite observing and sketching sites, the three craters Theophilus, Catharina and Cyrillus. Mountains are the highlight of day 21. The Apennines, and the large craters Kepler, Copernicus and Tycho are beautiful at lunar sunset. The last quarter moon has arrived.

Last Quarter Moon day 22 -27 The moon rises at midnight, and sets at noon. You really have to be dedicated to view this phase, or maybe just sleep deprived. Mare Imbrium and Copernicus are darkening on day 23. On day 24 through 27, most observers are sleeping when the moon is visible. Use binoculars to observe earthshine over the surface of the moon. These are the days (or rather nights) to turn your eyes, binoculars or telescopes to other wonders of the night sky: planets, comets, meteor showers and galaxies. Say good-night to our close neighbor. If you didn’t catch all these features, there’s always next month!

A moon map with almost all the features labelled

Check out all 6 Apollo landing sites, plus moon phase/landing site maps on this flyer I made for the GRAIL mission launch week in September 2011. (PDF)

USNO’s great Phases of the Moon and Percent of the Moon Illuminated pages

Here’s the original 1990 article I wrote for John Dobson’s Sidewalk Astronomy newsletter. My mom contributed the adorable lunar drawings.

My Sketches at the Eyepiece website

My sketch of the moon same lunar day as Galileo's sketch

Image take at eyepiece of 70mm TV Ranger while sketching on 7/14/09

Galileo’s drawing of the third quarter moon was made on December 18, 1609 according to widely accepted dates calculated by lunar scientist Ewen Whitaker. He used the solar colongitude and [...]]]>

My sketch of the moon same lunar day as Galileo's sketch

Image take at eyepiece of 70mm TV Ranger while sketching on 7/14/09

Galileo’s drawing of the third quarter moon was made on December 18, 1609 according to widely accepted dates calculated by lunar scientist Ewen Whitaker. He used the solar colongitude and the latitude of the subsolar point on the moon to determine the position of the terminator. You can read more about it here on the Reliving Galileo’s Observations page (sorry, this link is gone as of Oct 2011). Refer to his Journal for the History of Astronomy, Vol. 9, p.155 Galileo’s Lunar Observations and the Dating of the Composition of Sidereus Nuncius article.

You’ll have to scroll through the long article to find the colongitude and solar latitude of the original four engravings and seven small drawings. But you’ll find modern dates with a similar view of the moon. I was delighted to find that my sketch made on July 14, 2009 matched one of the 4 engraving dates!

The predicted “modern” dates refer to the pattern of lighting and the position of the terminator relative to the surface features. Libration will make the craters and other features displaced somewhat with respect to Galileo’s drawings. Most folks do not actually see any resemblance between now and then, but it is a great project – sketching Galileo’s 400 year-old moon in a 21st century way.

There is a quite a bit of agreement about the ”center” crater in Galileo’s sketch. It is most likely Albategnius. It was just on the terminator in my sketch too, and I accidentally made the crater a little larger than it really is. It’s just human nature I guess. Other features I can ID on both Galileo’s and my drawing are Mare Imbrium on both sides of the terminator, including some higher parts of Montes Caucasus lit on the unlit side of the terminator. I also can match the ghostly but well-lit trio of Ptolemaeus, Alphonsus and Arzachel just next to Albategnius on Galileo’s sketch, and I saw and sketched them too. Other sunlit Mare – Humorum (left) and Nubium (right) below Albagetnius also match up nicely.

The moon rises later each evening now. That means a late night for sketchers. Luckily my small 70mm Televue Ranger on a telepod mount requires no setup. I keep it permanently set up in the garage.

The features I’ve sketched on the 18-day moon begin with sunset on Mare Crisium – on the terminator [...]]]>

Eighteen-day moon

The moon rises later each evening now. That means a late night for sketchers. Luckily my small 70mm Televue Ranger on a telepod mount requires no setup. I keep it permanently set up in the garage.

The features I’ve sketched on the 18-day moon begin with sunset on Mare Crisium – on the terminator to the left on my sketch. Plato is the dark oval at north (top), with Mare Frigoris encircling it to the north.

The large mare closer to the terminator are Mare Serinitatis and Mare Tranquillatis. Mare Nectaris is the oval sea south of Tranquillatis. Mare Imbrium is the largest lunar basin on the moon – the large feature below (south of) Plato. It’s between Plato to the north and Copernicus and Kepler to the south.

Grimaldi, one of my favorite lunar features is the dark oval flooded basin to the right, south of Kepler. On nights of favorable libration, beyond Grimaldi, the ridges of Mare Orientale appear. Did I leave out Tycho? It is the magnificent crater to the south of Mare Nubium. Tycho’s long rays span 1800 km from Tycho to the small crater Rosse in Mare Nectaris. You can actually follow the ray to Rosse in my sketch!

There is so much to see and study on a the moon, especially if you have a lunar map. The nights after the full moon are wonderful lunar observing nights, if only you can stay up to observe on them!

It’s showtime! Sunlight reveals most of the lunar surface and the moon is visible all night long.

Sinus Iridum — the Bay of Rainbows — is visible near the north part (left in my sketch) of the terminator. It’s the little half circle. The Jura Mountains ring the western edge and catch the [...]]]>

It’s showtime! Sunlight reveals most of the lunar surface and the moon is visible all night long.

Sinus Iridum — the Bay of Rainbows — is visible near the north part (left in my sketch) of the terminator. It’s the little half circle. The Jura Mountains ring the western edge and catch the morning sun. It looks like a smile. This is one of my favorite lunar features to view and also to sketch.

Mare Imbrium is the large lunar mare just south (right) of Sinus Iridum. As the moon approaches full, the large craters Copernicus and Tycho take center stage. Moving left to right across the terminator we first see Copernicus. It’s 93 kilometers in diameter and its rays will be much more visible at full moon, thought they are impressive today, too!

Tycho lies in a field of craters near the south limb. Its massive ray system is beginning to appear. Watch it over the next few nights and trace the rays as they span over 1500 kilometers. Its diameter is 85 kilometers, which makes it a little smaller than Copernicus.

Closer to the terminator, another crater with spectacular rays at full moon appears tonight as a little white crater circle between Copernicus and the terminator. That’s Kepler! Oval Mare Humorum appears directly opposite Mare Crisium, and the look to be about the same size, which they actually are!. The small crater on the left edge of Mare Humorum is Gassendi, another lunar feature I love to sketch. Shickard is the final lunar feature on the right terminator. Wow! That was a lot of fun, to try to identify major features on a tiny 2-inch sketch! Full moon next!

My photo of the eleven-day moon

This year, my observing project is to recreate as many of Galileo’s original telescopic observations as I can. I’ll be using my smallest telescope, a 70mm refractor, and making my sketches using a 25mm eyepiece for a magnification of 19x. Each of my lunar sketch pages will each show three [...]]]>

three-day old waxing moon

This year, my observing project is to recreate as many of Galileo’s original telescopic observations as I can. I’ll be using my smallest telescope, a 70mm refractor, and making my sketches using a 25mm eyepiece for a magnification of 19x. Each of my lunar sketch pages will each show three sketches on the page. My first sketch is an “outline” of major features. The second sketch shows more detail, and the third is the final sketch. When I’ve matched all of Galileo’s lunar sketches, I’ll make a comparison montage.

The three-day waxing gibbous moon is high enough above the western horizon and far enough away from the setting sun to be easily visible. Earthshine illuminates the unlit features, and sun shines on the narrow crescent. Mare Crisium (the Sea of Crisis) is the oval dark geological feature visible on the lower right edge of the three-day-old crescent moon.

The crater Picard can be seen within the smooth surface of Mare Crisium. Along the terminator are some distinctive craters and other features, visible even at 19x. Following the terminator from right to left in my sketch, are dark Mare Fecunditatis and the large oval craters Langrenus, Vendelinus, and Petavius, all partially lit by the sunrise on their walls.

Petavius, the third of the 4 evenly spaced, and similarly sized craters shows some of the prominent crater floor structure of central peak and rimae – which I sketched as a dark angluar line. Funerius, fourth and last of the big craters on the terminator tonight, are near the two smaller craters, Snellius and Stevenius. In my sketch, I just show the crater floors flooded with shadow.

Earthshine reveals Mare Imbrium and Mare Serenitatis, Nubium and Humorum. And I was able to see the crater Aristarchus (the white feature top middle of the earthshine) and Plinius and Linne — the small white features in the lower middle of earthshine.

Use the link below to Hitchhikers Guide to the Moon to identify other features.

Hitchhikers Guide to the Moon

Sketch of Petavius

Sketch of Langrenus, Vandelinus, Petavius, and Furnerius a few days after full moon February 3, 2007, a 16 day-old waning moon.

My photo of the 3-day moon