Jonathan Crowe

My Correct Views on Everything
↳ Astronomy & Space

At Ceres

Ceres in Half Shadow

As of today the Dawn spacecraft is now in orbit of Ceres. Because Dawn’s trajectory puts it in the dwarf planet’s shadow, it’ll be the middle of next month before se start seeing better-resolution images than we’ve seen so far as it approached. The above images were taken from 40,000 km away on February 25.

Meanwhile, early images of Ceres have already been assembled into a preliminary equirectangular mosaic:

Ceres (mosaic)

No labels yet, because nothing’s been named yet: this is the first time we’ve seen these features. But Gazeteer of Planetary Nomenclature says that, in keeping with Ceres’ origin as the name for the Roman goddess of agriculture, Ceres’ craters will be named for “[g]ods and goddesses of agriculture and vegetation from world mythology”; other features will be named for agricultural festivals.



A newly reprocessed view of Jupiter’s moon Europa, based on images from the Galileo mission, has been released. “To create this new version, the images were assembled into a realistic color view of the surface that approximates how Europa would appear to the human eye.” Image credit: NASA/JPL-Caltech/SETI Institute.

Geologic Maps of Vesta

Geologic map of Vesta

Geologic maps of Vesta, the asteroid visited by the Dawn spacecraft between July 2011 and September 2012, have been produced for a special issue of the planetary science journal Icarus. Above, a global geologic map of Vesta, compiled from 15 individual quad maps and using a Mollweide projection (Vesta itself is decidedly non-spheroid, but still). Image credit: NASA/JPL-Caltech/ASU.

Previously: Atlas of Vesta.

Moon and Comet Maps

OSIRIS map of Comet 67P/Churyumov-GerasimenkoTopography of Earth's moon

Maps of planets, moons and other objects in our solar system always get me excited, though truth be told they were among the less popular posts on my old Map Room blog. Here are a couple of rather colourful recent examples:

Image credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA (above left); NASA/Colorado School of Mines/MIT/GSFC/Scientific Visualization Studio (above right).

Geologic Map of Mars

Geologic Map of Mars

As I said during the Q&A part of my fantasy maps presentation at Readercon (see previous entry), maps of other worlds in the solar system are usually images from space probes that have been set to a map projection. The key word is usually. On Monday the U.S. Geological Survey released a geologic map of Mars that “brings together observations and scientific findings from four orbiting spacecraft that have been acquiring data for more than 16 years.” Via io9 and Wired.

Astronomy in the Pontiac

Whatever the quality of the Pontiac’s roads, its skies are very good for astronomical observing — especially when you consider how close we are to Ottawa. From my backyard, which is not well shielded from porch and street lighting, I’ve gotten magnitude-five views with the naked eye — suffice to say, the Milky Way is in fine form during the summer. (Clouds are a wrinkle, though: they never fail to turn up during neato ephemeral events.)

In that vein I note with interest a group called AstroPontiac, and its Indiegogo campaign to raise funds to buy a roll-off roof observatory and a couple of telescopes. They’re trying to raise $12,500, which seems modest, but their goal of providing a site for amateur observing is fairly low-cost, considering. Ottawa Citizen coverage.

Ganymede and Mercury

Geologic map of Ganymede

The USGS has published a geologic map of Ganymede, Jupiter’s largest moon and the largest moon in the Solar System, based on imagery from the Voyager 1, Voyager 2 and Galileo probes. Via Centauri Dreams, Sky and Telescope.

Meanwhile, Sky and Telescope has produced a Mercury globe based on MESSENGER imagery. They already produce both visual and topographic globes of the Moon and Mars, as well as a globe of Venus coloured for elevation. (I’m crossing my fingers for globes of the outer moons, myself.)

I’m big on maps and globes of the rest of the Solar System. Recent entries: Maps of Mercury; Atlas of Vesta; A Topographic Map of Titan.

Ceres and a Supernova

Supernova in M 82 Today was a good day on the astronomy front. Data from the Herschel space observatory has revealed the presence of water vapour around Ceres, the largest object in the asteroid belt (this is even more cause to look forward to the arrival of the Dawn spacecraft there next year). And a supernova has been detected in M82, a galaxy close enough and bright enough to be seen through amateur telescopes (I’ve done so on more than one occasion). So: lots of awesome. (Photo credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright.)

Maps of Mercury

H-12 Michaelangelo

The USGS has released quad maps of the planet Mercury as a set of PDF files: “The 1:5 million-scale series of Mercury maps divides Mercury into 15 quadrangles, H-1 through H-15 (five Mercator, eight Lambert Conformal, and two Polar Stereographic quadrangles). The base mosaic was produced with orbital images by the MESSENGER Team and released by NASA’s Planetary Data System on March 8, 2013. This new global mosaic includes 100% coverage of Mercury’s surface.”

Proxima Centauri

Proxima Centauri

At 4.24 light years away — only 40 trillion kilometres! — Proxima Centauri is the second-closest star (after the Sun, of course). Even so, most people have never seen it, because it’s ridiculously hard to see. Due to its position in the sky it cannot be seen north of 27° N latitude, and even then you need a telescope because even the closest red dwarf cannot be seen with the naked eye. And even through the telescope I don’t think Proxima stands out from the rest of the starfield. (“Which pinpoint is it? This one? Oh. That’s nice.”) But! The Hubble to the rescue! Here it is, in red and infrared light. Image credit: ESA/Hubble & NASA.

Gordan Ugarkovic


Croatian software developer Gordan Ugarković plays with NASA imagery in his spare time, processing colour composites from raw data, mostly from the Cassini mission. The results are stunning, and can be seen on his Flickr photostream. His latest, a jaw-dropping wide-angle mosaic of Saturn, is getting all sorts of raves. Image credit: NASA/JPL/SSI/Gordan Ugarković.

Atlas of Vesta

Atlas of Vesta

An atlas of Vesta, comprising a series of 29 quad maps (mirror) assembling visual and relief data from the Dawn spacecraft’s visit to the large asteroid between July 2011 and September 2012, has been released.

Andromeda through the Subaru Telescope

Andromeda Galaxy (M31), Subaru telescope

The above image is not the best picture of the Andromeda Galaxy ever taken, not by a long shot. It is, however, a significant one. It’s a test image taken by the 8.2-metre Subaru Telescope’s Hyper-Suprime Cam, an 870-megapixel, three-ton imager mounted on the telescope’s f/2 primary focus. Which is to say that it produces absurdly high-resolution images (here’s a 35-megapixel, 6000×5957 version).

But what raised my eyebrows and dropped my jaw was the field of view: 1.5 degrees of sky is just preposterous on a telescope with a 15-metre focal length. This image of the Andromeda Galaxy was taken in a single shot. How do I explain how freaky that is? My 80-mm refractor, with its 500-mm focal length, could get the entire Andromeda Galaxy in the eyepiece, but not my larger scopes. Most amateur photography of this galaxy involves photographing pieces of the galaxy (in, say, a 2×3 grid) and assembled into a final mosaic. A single shot on a telescope that size? The mind boggles.

Pluto’s Problematic Cartography

We’re still two years from the New Horizons flyby of Pluto, but the cartography of the solar system’s most famous dwarf planet — based on Hubble imagery — is already several kinds of problematic, as Emily Lakdawalla explains in a post that also explains how the cartography of other worlds is done. (Key challenges include defining the north and south pole — which one is which? — as well as a prime meridian.)

Solstice CME

Sun Emits a Solstice CME

The Sun marked the solstice with this coronal mass ejection. Full-disk view. The Sun laughs at your puny fireworks. Image credit: NASA/SDO.

IC 2944

The Very Large Telescope Snaps a Stellar Nursery and Celebrates Fifteen Years of Operations

The European Southern Observatory, one of my favourite sources of open-licence astrophotography, marked the 15th anniversary of its Very Large Telescope by releasing this new image of IC 2944, a stellar nursery some 6,500 light years away in the constellation Centaurus. The picture combines visible light with narrowband hydrogen-alpha and oxygen-III emissions. Check out all the Bok globules! Image credit: ESO.

The Ring Nebula

Ring Nebula (M57)

Today a new Hubble image was released that promises “the most detailed observations ever” of the Ring Nebula (Messier 57), a planetary nebula about 2,300 light years away. It’s easily spotted in backyard telescopes (I’ve seen it many times myself). This image, taken through a combination of regular red, green and blue filters along with narrowband filters that reveal specific emissions, is good enough to form the basis of a 3D model. And if that’s not enough Ring Nebula for you, here’s another image combining Hubble narrowband data with ground-based infrared observations that reveals the nebula’s outer halo. Image credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.

A Topographic Map of Titan

Global topographic map of Titan (NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann)

The Cassini team has released a global topographic map of Saturn’s moon Titan. What makes this map interesting is the fact that, due to its thick atmosphere, Titan can only be mapped by radar during Cassini’s close flybys. As a result, only half of its surface has been imaged, and only 11 percent has topography data. For this map, the remainder was, well, extrapolated:

Lorenz’s team used a mathematical process called splining — effectively using smooth, curved surfaces to “join” the areas between grids of existing data. “You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess,” he said. “If you pick a point, and all the nearby points are high altitude, you’d need a special reason for thinking that point would be lower. We’re mathematically papering over the gaps in our coverage.”

Topo maps of parts of Titan have been released before, but not for the entire moon. See previous posts on The Map Room: Titan in Stereo; Topography of Titan.

Image credit: NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann.

NGC 6559

NGC 6559 (ESO)

Last week, the European Southern Observatory released this image of NGC 6559, a nebula some 5,000 light years away in the constellation Sagittarius. This image combines visible light with the hydrogen-alpha emission band (also visible, but specific) and was taken by the Danish 1.54-metre telescope at ESO’s La Silla observatory in Chile. Image credit: ESO.

A Year of the Sun

The Sun: One Year in One Image

The Sun never looks like this. This is a composite image, assembling 25 separate observations by NASA’s Solar Dynamics Observatory in the extreme ultraviolet wavelength of 171 ångströms (17.1 nm) over an entire year (April 2012 to April 2013). It reveals where the active regions on the Sun (sunspots, solar flares) are most commonly found. For something even more neat, follow this link and watch the video showing the Sun over a three-year period, two frames per day. Image credit: NASA/GSFC/SDO.

The Horsehead in Infrared

Horsehead Nebula

A magnificent new infrared image of the iconic Horsehead Nebula from the Hubble Space Telescope has been released to mark the 23rd anniversary of its launch (NASA, ESA). The false-colour image takes observations in the near infrared wavelengths of 1.1 and 1.6 µm and assigns them to the red and green channels, respectively. Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

New Habitable-Zone Planets

Kepler 62 system (artist's conception)

The Kepler mission has discovered two new star systems with planets in the stars’ habitable zones. Two of the five planets detected in the Kepler-62 system, 62e and 62f, and one of the two planets detected in the Kepler-69 system, 69c, orbit at a distance where surface water is possible. These are the smallest habitable-zone planets to be discovered to date: 62f is only 40 percent larger than the Earth, 62e is 60 percent larger, and 69c is 70 percent larger.

Kepler-62 is a K2 orange dwarf some 1,200 light years away; 62e and 62f have orbital periods of 122 and 267 days, respectively; the three other detected planets orbit very near their sun. Kepler-69 is a G-type star similar to (but a little smaller than) the Sun, 2,700 light years away; 69c’s orbital period is 242 days. Kepler uses the transit method to detect extrasolar planets.

Image credit: NASA Ames/JPL-Caltech (artist’s concept of Kepler-62f).

Previously: First Habitable-Zone Planet Confirmed.

The Small Magellanic Cloud’s Wing

Under the Wing of a Dwarf Galaxy (NASA, Chandra, 04/03/13)

Here’s a look at the tip of the “wing” of the Small Magellanic Cloud — more precisely, a group of open clusters known collectively as NGC 602, surrounded by a nebula known as N90. It’s a composite image combining visible-spectrum light from the Hubble telescope, infrared light from the Spitzer telescope (in red) and X-ray light from the Chandra telescope (in purple); visit the image’s page on the Chandra website to see each separately. The X-ray observations reveal stellar formation in areas that did not turn up in visible or infrared light. Image credit: NASA/CXC/Univ. Potsdam/L. Oskinova et al. (X-ray); NASA/STScI (optical); NASA/JPL-Caltech (infrared).

Messier 77

Messier 77 (Hubble)

I have a weakness for pretty pictures of spiral galaxies. This Hubble image of Messier 77, a barred spiral 47 million light years away in the constellation Cetus, more than qualifies. It’s a somewhat false-colour image, combining hydrogen-alpha (red), infrared (814 nm) and blue light. Image credit: NASA, ESA and A. van der Hoeven.

Or if star-forming regions are your thing the way spiral galaxies are mine, how about this Herschel image of molecular cloud W3?

A Nearby Brown Dwarf Binary

WISE 1049-5319 We just found another star system in the neighbourhood. Say hello to WISE J104915.57-531906, a brown dwarf binary star system recently discovered by astronomer Kevin Luhman only 6.5 light years away. That makes it the third-closest star system, after the Alpha Centauri trinary (AB plus Proxima) and Barnard’s Star. Don’t be surprised it’s taken so long to find. Close stars aren’t always visible: even the closest red dwarfs — Proxima Centauri and Barnard’s Star — can’t be seen without a telescope, and brown dwarfs are fainter still; they’re pretty much infrared-only. WISE 1049-5319 (for short!) was detected by its rapid motion relative to background stars in Wide-field Infrared Survey (WISE) imagery, which suggested that it was close by. Checking older sky survey images confirmed its distance; subsequent observations by the Gemini Observatory (above) confirmed that it was a brown dwarf binary. Article (PDF). Image credit: NASA/JPL-Caltech/Gemini Observatory/AURA/NSF. Via Bad Astronomy.

False Colour Mercury

False Color View of Mercury

Mercury isn’t normally this colourful. This is a false-colour mosaic built from images taken by the MESSENGER probe through several different narrowband filters during its colour base map imaging campaign. The colours accentuate differences in the composition of Mercury’s surface rocks. Caloris Basin is at the upper right in this view. Here’s the other side of the planet. More information here. Image credit: NASA/JHUAPL/Carnegie Institution of Washington.

Lunar Gravity Map

Free-Air Gravity Map of the Moon

NASA has released a free-air gravity map of the Moon: “If the Moon were a perfectly smooth sphere of uniform density, the gravity map would be a single, featureless color, indicating that the force of gravity at a given elevation was the same everywhere. But like other rocky bodies in the solar system, including Earth, the Moon has both a bumpy surface and a lumpy interior. … The free-air gravity map shows deviations from the mean, the gravity that a cueball Moon would have.” Gravity data comes from the GRAIL mission, with the digital elevation model provided by the Lunar Reconnaissance Orbiter laser altimeter. Image credit: NASA’s Goddard Goddard Space Flight Center Scientific Visualization Studio.

Messier 106

Messier 106

An image released today of spiral galaxy Messier 106, 23.5 million light years away in the constellation Canes Venatici, is the work of astrophotographer Robert Gendler; he combined archived Hubble image data with his and Jay GaBany’s ground-based observations, which provided colour data for the outer spiral arms. M106 is an active Seyfert galaxy with a supermassive black hole at its centre. Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and R. Gendler (for the Hubble Heritage Team); acknowledgment: J. GaBany.

Space Pictures for the New Year

Backlit Saturn (NASA/JPL-Caltech/SSI)

Time for some more awesome space pictures. Last month the Cassini team released this exquisite backlit image of Saturn, taken while the Cassini probe was in Saturn’s shadow. It’s an enhanced-colour view through infrared, red and violet filters.

Elsewhere in the Saturn system, there’s Jason Major’s colour composite of Saturn’s moon Dione, based on Cassini imagery from December 23. Moving from one of Saturn’s moons to our own, here are an oblique view of Taurus Littrow, the landing site of Apollo 17, from the Lunar Reconnaissance Orbiter, and César Cantú’s excellent wide-field shot of the Moon.

Continue reading this entry

Tau Ceti

Tau Ceti has been a focus of the science-fictional imagination for decades. Because we knew nothing about exoplanets, because we believed that binary star systems were unlikely to have room for planets in stable orbits, because we believed that life-sustaining planets were not possible around red dwarfs (neither of which are believed to be true now), we focused on Tau Ceti — a G-type yellow sun much like ours (though smaller) less than 12 light years away, with no stellar companion — as the most likely candidate for nearby habitable planets. Later theories discounted the possibility, citing the star’s low metallicity (which reduced the likelihood of rocky planets).

By now you’ve probably heard, though, that Tau Ceti may — mayharbour at least five planets, if what has been found through a new detection method is in fact signal and not noise. If correct, the planets range from two to more than six Earth masses, with orbital periods ranging from 16 to 640 days. At least one of the planets falls within the star’s likely habitable zone. Article, press release.

It’s fuel for the imagination, like Alpha Centauri’s planet, and the fact that Tau Ceti is both visible to the naked eye (magnitude 3.5, easy but not particularly bright) and visible from the northern hemisphere doesn’t hurt. I’ve seen it, and wondered, myself.

Older Entries

Overhead, Without Any Fuss
Alpha Centauri Bb: Closest. Exoplanet. Ever.
A Catalogue of Dying Stars
Elsewhere in the Universe
Coronal Mass Ejection, August 31
The View from Bradbury Landing
U Camelopardalis and Other Space Pictures
Messier 10 and Other Space Pictures
The Life and Death of Planet Earth
Ceci n’est pas une collision
Transit of Venus
Andromeda: It’s Coming Right for Us!
The Ultraviolet Universe
Messier 78 and Other Space Pictures
The Protoplanetary Egg Nebula
The Tarantula Nebula Again
Tarantula Nebula Panorama
Today’s Coronal Mass Ejection
New Moon Globe Released
Messier 9
100 Super-Earths Within 30 Light Years
Unveiled in Ultraviolet
Geologic Map of Io
Atlas of the Galilean Satellites
How Iapetus Got Its Ridge
More Moon Maps
Mercury’s Hovnatanian Crater
NGC 3324
Radio Waves
The Helix Nebula in Infrared
The Eagle Nebula in Infrared and X-Ray
M82 Detail
Comet Lovejoy Lives!
Deep Sky Roundup
Cassini’s Dione Close-Up
Mercury’s Bartok Crater
Jupiter Rotation
First Habitable-Zone Planet Confirmed
Orthographic Mercury
Cygnus X
A New Lunar Topo Map
Space Station Time Lapse Video
A Near Miss That’s Hard to See
Solar Active Region 1339
Astrophotography and Copyright
Messier 96
A Supernova Remnant in Infrared and X-Ray
How Uranus Got Its Tilt
Vesta’s South Pole
Holmberg II
An Aurora from Orbit
Cassini’s Hall of Fame
Mercury’s North Pole
Uranus and Neptune in Infrared
NGC 2100
Are Rocky Planets Downsized Gas Giants?
The Moon’s North Pole
The Dumbbell in Infrared
Purple Galaxies
Stars and Storms
Vesta’s Cratered Landscape
NGC 3521
The Necklace Nebula
Five Moons
Magellanic Superbubble
The Moon and the Earth’s Axial Tilt
NGC 634
Full-Frame Vesta
Vesta’s Northern Hemisphere
Orbiting Vesta
Neptune’s Anniversary
Davide de Martin, Astroimage Processor
Saturn’s Encircling Storm
The VLT Survey Telescope and the Omegas
Tycho Crater Close Up
Mercury’s Terminator
Chez Helene
Approaching Vesta
A Closer Look at Centaurus A
Crescent Mercury
Centaurus A
NGC 4214
El Cielo de Canarias
Messier 5
NGC 2174 in Infrared
Arp 273
Observing on Ellesmere Island
NGC 3582
Messier 12
Rho Ophiuchi in Infrared
NGC 5882
Habitable Worlds Around White Dwarf Stars?
NGC 371
Orbiting Mercury
Mars Mosaic
Tycho’s Supernova in X-Ray
Sharpless 284 in Infrared
A Hubble Image in Two Minutes
Solar Prominence Eruption
NGC 5584
NGC 6729
Tarantula Nebula
Farside Mosaic
Outside In: An IMAX Fly-Through of the Saturn System
Hot Enceladus
NGC 247
Christian Constellations
Messier 15
Rhea, Dione and the Rings
Sidereal Motion
Review: Gas Giants
Nearside Mosaic
NGC 6384
Nostalgia for the Light
NGC 2841
M78 Image Wins ESO Contest
Rendezvous with Tempel