The late hours of Monday night (24.08.09) brought an opportunity to take in a quick observation of Jupiter with the 25×100 binoculars. Initially I could only discern three of the Galilean moons, but further investigation revealed the fourth elusive satellite — Io — hugging close by Europa. Upon checking ‘The Night Sky’ section in my August edition of Astronomy Now I realised that I was witnessing a burgeoning occultation as Io converged upon Europa. Unfortunately I was unable to watch this entire Jovian event unfold, but it was fascinating to see the wafer-thin gap between the shimmering moons slowly disappear as they drifted towards their celestial rendezvous.
Posts Tagged ‘Ganymede’
Jul
15
2009
Three Times the Charm
Jupiter, the majestic giant of the solar system, has always been my favourite planet. While Saturn delivers undeniably glorious views; Jupiter, at least for me, has always stolen the show. Having suffered a grueling month of cloudy evenings, and twilight nights, the chance to take in an observation of this dazzling planetary behemoth early on Saturday morning was a welcome one.
The fact that Jupiter was in conjunction with Neptune, and the star µ (Mu) Capricorni just added to the celestial spectacle. My view however was to be a short lived one. Due to the urban geography of the neighbourhood; both planets remained in my sights for only 16 minutes before disappearing behind the row of three storey buildings that line the front of the house.
A Planetary Dance
Despite my brief window of opportunity I was afforded a stunning observation. The 25mm Celestron plössl revealed the equatorial belts of Jupiter as rust coloured bands, while the four moons: Callisto, Ganymede, Io, and Europa beamed like a string of brilliant diamonds against the dark sky. Having conducted my most recent observations of Jupiter with the 25×100 Strathspey binoculars; it was a real pleasure to see this distant world with such clarity.
While Jupiter made a striking impression; Neptune, bathing in the alabaster light of the waning gibbous Moon, was just discernible as a faint point of light with a hazy turquoise hue. This is the second time that I have been fortunate enough to view this remote ice giant which sits just over 2 billion miles from the Earth. Gazing upon this diminutive speck you realise that you are actually looking at the end of planetary space beyond which begins the Kupier belt, the Oort cloud, and finally galactic space. An amazing, but rather humbling thought.
In between this planetary dance µ Capricorni, a yellow-white F3 IV type subgiant that lies 90.2 light years away, cast it’s white incandescent light upon the scene. Subgiants are stars which have, or are in the process of ending hydrogen fusion. Beyond this point in it’s evolution µ Capricorni is destined to become a red giant that may, at some point in the far flung future, bloom into a planetary nebula.
As quickly as Jupiter, and Neptune had risen above the roof tops then no sooner were they gone. Hidden from view by the suburban sprawl. Left alone with the Moon, which made for a very tempting target, I decided to make the most of it by taking in one more special observation before packing up.
One Giant Leap
Forty years ago, on the 20th of July 1969, NASA realised the mandate that the late President John F. Kennedy had laid down eight years earlier: to land a man on the Moon, and return him safely to the Earth. Apollo 11, carrying the astronauts Neil Armstrong, Michael Collins, and Edwin ‘Buzz’ Aldrin, set down near the south western shore of the Mare Tranquillitatis, and made history.
It was here that I aimed the telescope in search of three small craterlets: Aldrin, Collins, and Armstrong; all of which form a chain just east of the larger impact craters Ritter, and Sabine. After ten minutes of continued scrutiny the 6mm plössl finally resolved these three small monuments to the first manned lunar landing. In reality Aldrin, Collins, and Armstrong range in size from 2.4 Km to 4.6 Km giving some idea of just how vast this region of the Moon really is.
Letting my gaze drift down not far from Collins I imagined the quiescent remnants of Tranquility Base, also known as Statio Tranquillitatis, forever frozen in time by the vacuum of space. A lasting testament not only to the triumph of Apollo 11, or the United States of America, but probably the single greatest achievement Mankind has ever made. Where the 21st Century will take space exploration is anyone’s guess, but hopefully one day humanity will find itself once again voyaging to the Moon, and beyond.
If you have the time then why not follow in the footsteps of the Apollo 11 astronauts by tracking down the craterlets Aldrin, Collins, and Armstrong yourself. The best time to do this is nearer the end of the month, on the 27th of July, five days after the new Moon. I’d also recommend that you take in an view of Jupiter, and Neptune as they drift past one another in the night sky. This is the second of three conjunctions that will take place between these two planets during the year, with the third one to occur on the 20th of December. Have fun, and happy observing!
Mar
06
2009
Europan Dreams
The Jovian moon of Europa is surrounded by plenty of mystery and lots of speculation. Slightly smaller than our own moon, it is composed largely of silicate rock with a tenuous exosphere of molecular oxygen and a possible iron core. The surface is predominantly made of ice and while it is checkered with streaks and fractures it is in fact one of the smoothest in the whole solar system. This smooth but variegated surface resembles images of sea ice as seen on Earth and has led many planetary scientists to believe that there is a vast subsurface ocean of liquid water below the frozen crust.
Tentative evidence for this ocean can be seen by looking at what has been termed ‘chaos terrain’, an area where some believe the subsurface ocean has melted through the icy exterior due to tidal up-welling. Other evidence can be found in the data that the Galileo probe obtained, showing that Europa has a weak magnetic field induced through Jupiter’s own, suggesting the presence of a conductive sub layer i.e an ocean of liquid saltwater .
If indeed there is an ocean under the frigid surface, then it is plausible to think that extraterrestrial life might exist, but what kind of life? This proposition hinges on one fact: the temperature of Europa’s ocean. While the moon may possess an internal energy source, it is insufficient to provide the necessary heat to help maintain biological processes. However, the orbital resonance between Jupiter, Io, Europa and Ganymede probably heats the interior of the moon through tidal flexing which would ensure that the ocean remained liquid. The energy from the tidal flexing could also possibly be released through hydrothermal vents much like the black and white smokers that are found on Earth’s ocean floor. Europa’s hydrothermal vents could provide the ideal conditions for a more modest ecosystem than those found around Earth’s vents but they would support a hot, nutrient rich environment in which micro organisms like anaerobes and archaea could potentially thrive.
The only way that we will know for sure what lies beneath Europa’s mysterious surface is by going there, and it looks like we’re going to get our chance. NASA and ESA announced near the end of last month that they were going to undertake a joint mission to launch two probes by the end of the next decade to study Jupiter and it’s four moons. Just what discoveries will be made about Europa is anyone’s guess, but they’re sure to be extremely exciting and very compelling.
Nov
29
2008
Two Different Views
Yesterday evening presented me with a wonderful chance to photograph Venus and Jupiter as they both slowly made their way towards the western horizon. The shot below was a 1/3 second exposure taken using a 70mm focal length at ISO 100 with an f/stop of 5.6. I adjusted the white balance to shaded and set the quality mode to RAW. The image was then post processed by adjusting the white balance and applying a soft focus effect in Photoshop.
Once I had taken a good number of exposures through the a200, I thought it would be interesting to sketch the two planets through the 25×100 Strathspey binoculars. My intention here was to combine the two sketches into one final wide field image just as you can see below. The 25×100s don’t offer the best observational capabilities when viewing planets, but the final sketch offers a little more depth than the actual photograph above. I hope you enjoy both.
Oct
03
2008
Eccentric Circles
The weather in September, much like August was dominated by lots of cloud systems and plenty of rain fall, which of course meant that there were extended periods of observational inactivity. Out of the thirty days that make up the month of September, there were six nights where conditions were adequate for observing. During these six nights, I tracked the Galilean moons of Jupiter, so I thought I would take the opportunity to share a montage of renders that I produced on the back of these observations.