Third quarter moon, a half hour later

My small 70mm Televue Ranger was used for the moon images

Summer dark sky observing means short nights, and it’s usually too hot for comfort in the Colorado desert location we love. But Mojo and I decided [...]]]>

Moonrise over Chuckwalla Mountains July 3, 2010 about 11:30 p.m.

Third quarter moon, a half hour later

My small 70mm Televue Ranger was used for the moon images

Summer dark sky observing means short nights, and it’s usually too hot for comfort in the Colorado desert location we love. But Mojo and I decided to pack a cooler full of ice cubes, and take our chances. The predicted daytime high was 102 F, and it would be (we persuaded ourselves) a few degrees cooler at “our” spot. The low temperature for the night was forecast to be 75 degrees. We could live with that!

It didn’t get dark enough to observe anything except planets until 9:00 p.m. and so we only had two and a half hours of dark sky before moonrise would make it too bright.

One of the benefits of living and observing in Southern California is that at latitude 33N, we can see deep into the southern skies.

Summer nights are just made for observing Scorpius. The Bug Nebula NGC 6302 is one of my favorites ever since I saw and sketched it high in the Australian skies in 1999. NGC 6231, the Table of Scorpius is another favorite. It’s an open cluster near Zeta Scorpii, the first star marking the Scorpion’s curvy tail.

This is a delightful region (great with binos too) full of Milky Way wonders, including emission nebula IC4628. Mojo captured the area beautifully in his image of Scorpius last night. The star cluster center bottom is NGC 6231, and the reddish patch just above it is the emission nebula IC4628.

This is the area I was aiming my big telescope at until about 11 p.m. when we could see the lunar light dome emerging. We finished up our projects and waited for that first “wedge” of moonlight to breech the mountain ridge to the east.

I took some afocal images using my Canon Powershot SD870IS Digital camera held at the eyepiece of my small refractor. I’m pretty happy with the results.

Since it was a short night, this is a short observing report.

Mojo’s report from the same night

The Chuckwalla Bench observing site. Scan the topography to see Chuckwalla Mountain to the east of our observing site (the green arrow).

Another third quarter moon observation

My first sketch of SL 9 impacts on Jupiter July 18, 1994.

My July 26, 2009 sketch of the impact on Jupiter, discovered by Anthony Wesley (upper left 11-o'clock spot)

Anthony Wesley's preliminary [...]]]>

December 1690 sketch of new dark spot on Jupiter by G. D. Cassini and changes to the spot over 18 days

My first sketch of SL 9 impacts on Jupiter July 18, 1994.

My July 26, 2009 sketch of the impact on Jupiter, discovered by Anthony Wesley (upper left 11-o'clock spot)

Anthony Wesley's preliminary (a raw frame from his video) showing new impact of Jupiter, June 3, 2010

The word spread like wildfire, and soon amateur and professional astronomers around the world were calculating when the impact area would rotate around the planet, to be hopefully visible from their own location, telescope or observatory. Would the impact leave a scar? No one knew for sure, but more observations were needed.

We’ve seen and documented three impacts to hit Jupiter since 1994 — but how many have we missed? Impact events leave no long-lasting scars on the surface of Jupiter. Jupiter’s bruises fade away.

Any science enthusiast who remembers 1994 will never forget the buildup to Shoemaker-Levy 9′s amazing impacts into Jupiter that summer. I have many sketches of what I observed visually those first nights when the world saw predicted cometary fragments hit Jupiter and leave visible impact scars. Astronomy clubs around the world saw increases in membership because of the press coverage.

I took my homemade 10-inch reflector telescope out on my back deck and observed and sketched Jupiter every clear night in the summer of 1994. I was, unwittingly at the time, continuing the tradition of citizen scientist recordings of visual astronomical observations — a tradition which goes back thousands of years.

Last year I was researching historical astronomical observations for my International Year of Astronomy (IYA) podcast series. I learned that Giovanni Domenico Cassini not only first saw Jupiter’s great red spot (called Jupiter’s permanent spot) in 1665, but he also observed and documented other large spots in December 1690.

Cassini’s sketched this feature over eighteen days in December 1690. His sketches show changes in the feature over time. His observations were published in 1792 as “Nouvelles descouvertes dans le globe de Jupiter.”

Today’s citizen scientists around the world observe their targets nearly every clear night. And when they see something unusual they immediately alert their community of colleagues. Sometimes, like in this case, other eyes or images confirm the observation. And when it is amazing enough, the world’s greatest eyes – Earth-based telescopes like Gemini, Keck, IRTF and even the orbiting Hubble Telescope — take aim.

Their eyes from Earth and space will make observations to delve deeper into Jupiter’s mysteries. Their data will complement observations of astronomy’s citizen scientists whose round-the clock and round-the-world nightly records are the eyes on the sky.

Ancient Astronomical Documents

Discovery of a Possible Impact SPOT on Jupiter Recorded in 1690

The Shoemaker-Levy 9 Spots on Jupiter: Their Place in History

1994 Comet Shoemaker-Levy 9 Impact

2009 Jupiter Impact

2010 Jupiter Impact

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!

Skymap Pro chart of Jupiter and Neptune (the square at left), December 28, 1612

My sketch of Neptune with Jupiter and the Galilean moons

Galileo made the first recorded observation of Neptune in 1612 when Neptune [...]]]>

Galileo noted a fixt star (at left), now known to be Neptune on this sketch from December 28, 1612

Skymap Pro chart of Jupiter and Neptune (the square at left), December 28, 1612

My sketch of Neptune with Jupiter and the Galilean moons

Galileo made the first recorded observation of Neptune in 1612 when Neptune appeared to be close to Jupiter from his viewpoint on Earth. The”fixed star” Galileo noted to left of Jupiter (the left most star) on his December 28, 1612 sketch was actually Neptune! The two planets appear close to each other several times this year.

This year, both planets come to opposition in August and for several months on either side of opposition, the two planets appear to temporarily move backwards against the background stars. This is called retrograde motion, and they pass near each other three times this year. On May 26, the planets were only 23′ (or 23 arc minutes) apart.  On July 9th, near when I made my sketch, the two planets appeared 33.5′ apart.  And on December 21, the Winter Solstice, you can look for Neptune below Jupiter, 32′ distant.  This is a great time to easily see both planets in the same low power field of view through a telescope! At higher magnification, they won’t be in the same telescopic field of view, but you’ll find Neptune with just a small nudge or “go-to” to the North.

Galileo observed Neptune in December 28, 1612 and again one month later on January 27, 1613. Then, on the next night, he noted that the two stars seemed further apart. If he had observed the two objects again on the next few nights he would have realized that one of the “stars” was moving.

If you have a chance to look at Jupiter in July 2009, you’ll easily spot Neptune if you know where to look. Here is a star chart for July 25th showing the location of both planets low in the southeast at 11:30 p.m. They are rising, and will be higher in the sky later on. And here is a closeup star chart showing the tip of Capricornus. Use this chart to locate Jupiter in your eyepiece, and then you can easily follow the stars to Neptune. These star charts are made by Sky Map Software.

Neptune’s color in the telescope view is striking! It stands out as a bluish star to the north of Jupiter – about twice the distance north as the width of Jupiter and moons. After I sketched the pair of planets, I revved up the charting software, Sky Map Pro, and entered December 28, 1612. I was amazed to see the planets and moons layed out nearly as Galileo observed them. This may sound silly to you, but that 400 year-old view of the planetary lineup on 21st century software just took my breath away!

The full moon rises as the sun sets on the 14th day of the lunar month. A small telescope, such as the 70mm f.8.7 Televue Ranger I’m using for this series of sketches is a perfect instrument for full moon viewing. So are binoculars. The moon is [...]]]>

fourteen-day (full) moon

The full moon rises as the sun sets on the 14th day of the lunar month. A small telescope, such as the 70mm f.8.7 Televue Ranger I’m using for this series of sketches is a perfect instrument for full moon viewing. So are binoculars. The moon is a very generous target, and even the least expensive department store telescope will provide you many hours, days, months and years of inexpensive lunar observing fun!

The features you see on the full moon night are so different than the other nights. There are no shadows! So the features which stand out are the more reflective (bright white young craters and their ejecta) or the darker, less reflective mare.

Many new lunar observers think the full moon is too bright to view through a telescope. It’s not, but there are some tricks you can use to make your full moon view more enjoyable. One trick I like is to use a higher power eyepiece when viewing the full moon. That higher magnification dims the apparent brightness of the full moon. Another trick is to observe the full moon next to a streetlight or normal outdoor house lighting. We hate those lights when they ruin our dark skies, but they don’t hurt lunar viewing one bit, in fact they improve it! I don’t like to use moon filters or neutral density or polarizing filters when observing the moon. They diminish the sharpness of the features I want to view.

There are so many features I can identify on these sketches, but I’ll just mention the ones I have not covered before. My center sketch seems to be a little better than the “final” lower one. I can see, in addition to the great rayed craters Copernicus, Tycho and Kepler, lots of small bright white craters or ejecta. Proclus and Messier are near Mare Crisium, but it will take a map for you to find them. Proclus is a crater that is actually visible to the unaided eye at full moon, but I didn’t capture it on my sketch very well, probably because I made this sketch after midnight on a mid-week work night!

My photo of the fourteen-day moon

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

Jane's Head of Orion cluster

Astrophoto of Orion Head cluster by Morris Jones

Map of the constellation Orion

Galileo looked at the fuzzy patch surrounding the head of Orion through a telescope, and resolved many starts not previously known. He called it Nebulosa Orionis.

Look between the shoulder stars Betelgeuse and [...]]]>

Galileo's Head of Orion cluster

Jane's Head of Orion cluster

Astrophoto of Orion Head cluster by Morris Jones

Map of the constellation Orion

Galileo looked at the fuzzy patch surrounding the head of Orion through a telescope, and resolved many starts not previously known. He called it Nebulosa Orionis.

Look between the shoulder stars Betelgeuse and Bellatrix of the constellation Orion. The star you see with your unaided eye is Orion 39 or Lambda Orionis. Its Arabic name is Meissa. You can find this star on Galileo’s drawing by following the stars at the bottom of the drawing. The first star at left is 37 Phi1 Orionis. Three smaller stars follow. The next one is Meissa. It’s an amazing star! Surrounding the hot class O star (which also has a double) is a 150 light year ring of gas, which you can read about at Jim Kaler’s Stars website link above.

We now refer to the open cluster which contains this star as Collinder 69 or Sharpless 2-264.

A hand drawn original diagram of Galileo’s 21 stars can be found in Volume 3, page 964 of the National Edition.

my drawing

my sketch of Jupiter's rotation

Galileo published his observations in Sidereus Nuncius in March 1610: “On the 7th day of January in the present year, 1610, in the first hour of the following night, when I was viewing the constellations of the heavons through a telescope, the planet Jupiter [...]]]>

Galileo's drawing

my drawing

my sketch of Jupiter's rotation

Galileo published his observations in Sidereus Nuncius in March 1610: “On the 7th day of January in the present year, 1610, in the first hour of the following night, when I was viewing the constellations of the heavons through a telescope, the planet Jupiter presented itself to my view, and as I had prepared for myself a very excellent instrument, I noticed a circumstance which I had never been able to notice before, namely that three little stars, small but very bright, were near the planet…When on January 8th, led by some fatality, I turned again to look at the same part of the heavens, I found a very different state of things, for there were three little stars all west of Jupiter, and nearer together than on the previous night.”

“I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, as Venus and Mercury around the Sun; which was at length established as clear as daylight by numerous other subsequent observations. These observations also established that there are not only three, but four, erratic sidereal bodies performing their revolutions around Jupiter.”

Every amateur or accidental astronomer who first views Jupiter and its lineup of moons, is amazed at the view. Galileo’s 1610 discovery of these four moons orbiting Jupiter changed history. Looking at the Jovian moons through a small telescope, while trying to imagine Galileo’s first observations, takes my breath away!

A page from Sidereus Nuncius: 1610

First page of my observing log: 1989

My first sketches of the rotation of the four Galilean satellites: 1989

nine-day moon

Lunar creature features

Rabbit on the full moon

Night owls can enjoy the nine-day moon – it’s up all night long. In my sketch, the magnificent crater Copernicus is visible on the sunlit side of the terminator – on the right side of the lunar center. It looks so insignificant right now, but [...]]]>

nine-day moon

Lunar creature features

Rabbit on the full moon

Night owls can enjoy the nine-day moon – it’s up all night long. In my sketch, the magnificent crater Copernicus is visible on the sunlit side of the terminator – on the right side of the lunar center. It looks so insignificant right now, but at full moon, its spendid ray system is a naked-eye delight! Tonight you see the deep crater floor half lit by the sun. Here’s a closeup of Copernicus sketched through a larger telescope at higher magnification (185x versus 19x on these full disk drawings) on nearly the same day of the lunar month.

From now until full moon, the dark lunar mare start to resemble creature features. I see half of the rabbit on the moon in my sketch. Mare Fecundatis and Mare Nectaris make the ears and Mare Tranquillatis (the Sea of Tranqulilty) makes a cute little bunny head. You can see other creatures in my February 2009 What’s Up podcast about the moon, linked below.

As we near the full moon, the sun angle is more direct and crater wall shadows disappear. There are some other craters on the terminator tonight, which will reveal their amazing ejecta rays in a few more days when the moon is full. Towards the left edge of the terminator, Tycho is half lit now, but at full moon, its rays extend 1000 km. The spectacular walled plain Clavius is just starting to reveal its beauty. Through a telescope, when the entire crater is visible, you’ll see a dozen smaller craters on its floor.

My What’s Up Podcast, July 2007: The phases of the moon

My What’s Up Podcast, February 2009: Galileo’s and other first views of the moon through a telescope

My photo of the nine-day moon