Damian Peach, one of the most prominent planetary astrophotographers, assembled a sequence of his photos during the latest apparition of Mars into a video below. The video displays, in high definition, a full rotation of the Red Planet (24.622 hours).

Visit Damian’s webpage for more amazing astrophotography.

Despite having logged hours and hours of CCD data collection and reduction, Skymorph really helped me to get familiar with the latest tools (such as Astrometrica). I definitely recommend it to anyone wishing to start an astrometry program as you will learn the step-by-step process of using tools such as the MPC services, services from asteroid.lowell.edu, Astrometrica, etc. You’ll find new unknown objects and learn to distinguish them from false signatures; gain experience to follow up on your the discoveries (and even do precovery work) and learn to produce astrometry reports in the format accepted by the MPC.

My discovery of 2002 RO282 in NEAT/Skymorph data

In the 90′s and early years of the last decade, anyone with a medium-sized telescope and a CCD camera had pretty good chances to discover asteroids. Nevertheless, since NASA funded big surveys have started sweeping virtually the entire sky (visible from the northern hemisphere) every month, amateur discoveries require much bigger telescopes (0.5m and more) to allow one to reach beyond the 20th magnitude. A much cheaper alternative to owning a big telescope is to rent time on one. There are a few options out there, but I personally prefer the Lightbuckets remote observatory and the incredible 24″ Ritchey–Chrétien telescope from RC Optical Systems.

Lightbuckets LB-0001 - 0.61m (24") Ritchey-Chrétien

Located under the excellent northern hemisphere skies of southwestern New Mexico, LB-0001 equipped with Apogee Ulta 42 CCD camera (with quantum efficiency reaching staggering 90%) can easily reach beyond the 20th magnitude in a single 60s unfiltered exposure. The ability to observe objects fainter than 20th magnitude is crucial for minor planet hunting as the vast majority of brighter objects have already been found.

I discovered my first minor planet in the very first image set taken with LB-0001 (statistically, the odds of finding an object of ~21st magnitude in the 20′x20′ field of wiew of LB-0001 are pretty good). But the discovery of a minor planet is only the beginning. Further observations are necessary to determine the orbit well enough so that the object can be recovered at next opposition. This usually requires an arc of at least 2-3 weeks, but the longer the better.

The discovery animation of minor planet 239792. At the first measured position the object had brightness of V21.1, i.e. about million times fainter than one can see with a naked eye.

Once an object has been observed for 2 or more weeks, it is possible to search for identifications with previously-discovered provisionally-designated objects observed at only one opposition in the past. If an identification is made, one of the provisional designations is defined to be the principal designation. This is generally the earliest opposition at which a reasonable orbit was computed. An orbit is considered to be “reasonable” if it is good enough to use as a starting orbit to link the other observations.

Although numbering of a Main Belt asteroid usually requires observations from four oppositions (i.e. takes at least 4-5 years), with a good amount of luck your newly discovered object could be numbered within 1-2 months. If the observed arc from the current opposition can be used to link a few observations from the past, it is possible that the orbit will be refined well enough so that the object can be numbered. That is exactly the story of a minor planet (239792) 2010 EM34 I discovered using LB-0001.

2010 EM34 Discovery Astrometry

On March 9, 2010, during one of my regular searches in the area close to the ecliptic just before opposition, I noticed a previously unknown moving target. The data from the same night showed a few other brighter targets, so I did not select this object for a follow-up and reported it as a 1-nighter. Fortunately, the  Mt. Lemmon Survey (G96 ) swept the area of the sky into which my 1-nighter moved in 4 days and reported it to MPC. The processing routine determined that the two one-nighter observations belong to the same object and thus assigned it a provisional designation 2010 EM34.

2010 EM34 follow-up from March 21. The brighter minor planet close to the bottom is 171343.

After a week, on March 21, I observed the objects again extending the observed arc to 12 days. This follow-up observation was of a crucial importance. Thanks to the 12-day arc, MPC was able to link an observation by Kitt Peak-Spacewatch (691) on February 18, and later, two observations of 2010 EM34 by G96 on April 10 and April 12, extending the observed arc to 52 days. The 52-day arc determined the orbit well enough to find observations of the object from past years. Namely, the automated procedures linked observations from 1999 (1), 2003 (4), 2005 (1), 2006 (4) and 2007 (1).

2010 EM34, as it turned out, corresponds to 2003 US321 and 2006 JK71 but 2010 EM34 remained the principal designation because it was the observations of 2010 EM34 which were used to link all the past positions together.

Both 2003 US321 and 2006 JK71 were observed on two nights only. 2003 US321 was discovered by 691 on October 16, 2003 and observed again by LPL/Spacewatch II (291) on October 23, 2003. Two one-night observations of the object from September 16 and 28 were also reported but the automated routines at MPC were not able to link the observations to 2003 US321, because they were spaced too far apart (and the two-night orbit of 2003 US321 wasn’t accurate enough). 2006 JK71 was discovered at Mauna Kea (568) on May 1, 2006 and observed again by G96 on May 2, 2006.

Once the link was established, the orbit of 2010 EM34 could be calculated with sufficient precision to link one-night observations from 1999, 2005 and 2007. Consequently, the orbit was determined to be accurate enough so that minor planet could be numbered. 2010 EM34 received a permanent designation 239792 in the Minor Planet Circular 69935 and can now be named.

Sunrise Solstice at Stonehenge. The above image was taken during the week of the 2008 summer solstice at Stonehenge in United Kingdom, and captures a picturesque sunrise involving fog, trees, clouds, stones placed about 4,500 years ago, and a 5 billion year old large glowing orb. Even given the precession of the Earth's rotational axis over the millennia, the Sun continues to rise over Stonehenge in an astronomically significant way - Credit: APOD/Max Alexander, STFC, SPL

Certainly there is no good scientific reason for doing so. In the Northern Hemisphere the period of maximum daylight falls roughly between May 7 and August 7–in other words, the six weeks before and after the solstice. The period of maximum temperature, on the other hand, is June 4 through September 3. (The period of max temperature in the mid-latitudes always lags about 25 to 30 days behind the period of max daylight, due to the fact that the earth heats up and cools off relatively slowly.)

In 2005, thousands of people gathered at sunrise to see the sun rise through the 4,000 year old solar monument - Credit: APOD/ Pete Strasser (Tucson, Arizona, USA)

Here is what the Bad Astronomer has to say about the beginning of season.

Sources: Wikipedia, The Straight Dope, Bad Astronomy / Bad Seasons

Whimsical Vermeer composite that ran on APOD's fifth anniversary now digitally re-pixelated using many of the over 5,000 APOD images that have appeared over APOD's tenure

As during each of the 15 years of selecting images, writing text, and editing the APOD web pages, the occasionally industrious Robert Nemiroff (left) and frequently persistent Jerry Bonnell (right) are pictured above plotting to highlight yet another unsuspecting image of our cosmos. Although the above image may appear similar to the whimsical Vermeer composite that ran on APOD’s fifth anniversary, a perceptive eye might catch that this year it has been digitally re-pixelated using many of the over 5,000 APOD images that have appeared over APOD’s tenure.

It was a great honor to have a link to my blog post appear in the APOD website on October 15, 2009; you may remember:

The brilliant fireball meteor captured in this snapshot was a startling visitor to Tuesday (October 13, 2009) evening's twilight skies over the city of Groningen - Credit: Robert Mikaelyan

Moon Zoo is a new addition to the Zoo-universe, a collection of citizen science project that started a few years ago with the highly successful Galaxy Zoo. The project invites everyone to explore the lunar surface in unprecedented detail, with the resolution of up to 0.5m., courtesy of NASA’s Lunar Reconnaissance Orbiter (LRO) and its two Narrow Angle Cameras.

Moon Zoo asks the participants to classify and measure the shape of features on lunar surface with the main focus on:

• counting the number of and measuring the size of impact craters
• categorizing locations of interest such as lava channels, crater chains, lava flooded impact craters,  volcanic eruptive centers, etc.
• assessing the degree of boulder hazard by comparing boulder density on two images
• identifying recent changes on lunar surface by comparing LRO and Apollo photographs
• determining the location of space mission hardware on the Moon (Apollo landers, Luna rovers, European and Chinese probes)

Besides delivering high quality data which will address many questions of lunar science, Moon Zoo is also an excellent tool to promote lunar and space exploration and engage the public in learning about processes involved in scientific discoveries.

Infrared image of the Rosette molecular cloud in a three-colour composite made with observations from Herschel’s Photoconductor Array Camera and Spectrometer (PACS) and the Spectral and Photometric Imaging Receiver (SPIRE) - Credit: ESA/PACS & SPIRE Consortium/HOBYS Key Programme Consortia

The Rosette Nebula is located about 5,200 light years from Earth and is associated with a larger cloud that contains enough dust and gas to make the equivalent of 10,000 Sun-like stars. The Herschel image shows half of the nebula and most of the Rosette cloud. The massive stars powering the nebula lie to the right of the image but are invisible at these wavelengths. Each color represents a different temperature of dust, from –263ºC (only 10ºC above absolute zero) in the red emission to –233ºC in the blue.

The small spots near the center and in the redder regions of the image are lower mass protostars, similar in mass to the Sun. The bright smudges are dusty cocoons hiding massive protostars. These will eventually become stars containing around ten times the mass of the Sun and will significantly influence the formation of the next generation of stars.  The understanding of the formation of high-mass stars in our Galaxy is important because they feed so much light and other forms of energy into their parent cloud they can often trigger the formation of the next generation of stars.

Source: ESA

Artist’s impression of how Triton, Neptune’s largest moon, might look from high above its surface. The distant Sun appears at the upper-left and the blue crescent of Neptune right of center - Credit: ESO/L. Calçada

“We have found real evidence that the Sun still makes its presence felt on Triton, even from so far away. This icy moon actually has seasons just as we do on Earth, but they change far more slowly,” says Emmanuel Lellouch, the lead author of the paper reporting these results in Astronomy & Astrophysics.

On Triton, where the average surface temperature is about minus 235 degrees Celsius, it is currently summer in the southern hemisphere and winter in the northern. As Triton’s southern hemisphere warms up, a thin layer of frozen nitrogen, methane, and carbon monoxide on Triton’s surface sublimates into gas, thickening the icy atmosphere as the season progresses during Neptune’s 165-year orbit around the Sun. A season on Triton lasts a little over 40 years, and Triton passed the southern summer solstice in 2000.

Based on the amount of gas measured, Lellouch and his colleagues estimate that Triton’s atmospheric pressure may have risen by a factor of four compared to the measurements made by Voyager 2 in 1989, when it was still spring on the giant moon.

Carbon monoxide was known to be present as ice on the surface, but Lellouch and his team discovered that Triton’s upper surface layer is enriched with carbon monoxide ice by about a factor of ten compared to the deeper layers, and that it is this upper “film” that feeds the atmosphere. While the majority of Triton’s atmosphere is nitrogen (much like on Earth), the methane in the atmosphere, first detected by Voyager 2, and only now confirmed in this study from Earth, plays an important role as well.

Voyager 2 raw image of Neptune's satellite Triton taken from roughly 500,000 km. Evidence of complex surface features can be seen from this distance - Credit: NASA

Of Neptune’s 13 moons, Triton is by far the largest, and, at 2700 kilometers in diameter (or three quarters the Earth’s Moon), is the seventh largest moon in the whole Solar System. Since its discovery in 1846, Triton has fascinated astronomers thanks to its geologic activity, the many different types of surface ices, such as frozen nitrogen as well as water and dry ice (frozen carbon dioxide), and its unique retrograde motion.

Observing the atmosphere of Triton, which is roughly 30 times further from the Sun than Earth, is not easy. In the 1980s, astronomers theorised that the atmosphere on Neptune’s moon might be as thick as that of Mars (7 millibars). It wasn’t until Voyager 2 passed the planet in 1989 that the atmosphere of nitrogen and methane, at an actual pressure of 14 microbars, 70 000 times less dense than the atmosphere on Earth, was measured. Since then, ground-based observations have been limited. Observations of stellar occultations (a phenomenon that occurs when a Solar System body passes in front of a star and blocks its light) indicated that Triton’s surface pressure was increasing in the 1990′s. It took the development of the Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES) at the Very Large Telescope (VLT) to provide the team the chance to perform a far more detailed study of Triton’s atmosphere.

Source: ESO