Tuesday, September 21, 2010

Jupiter And Uranus At Opposition

At the moment, Jupiter and Uranus are very close together in the night sky and last night they were at opposition. An added bonus is that Jupiter is close to perihelion and is at its closest approach to Earth in many years.

Below is an image I prepared on Cartes du Ciel (North up) showing Uranus on top with Jupiter below it within a one degree circle at 23h local time (UTC +2).

The view in the telescope was stunning. Within the one degree view of my 25mm (mag x48) eyepiece both planets could be seen together. Jupiter with its retinue of the four Gallilean moons shone brightly at the top with the pale green/blue dot of Uranus lying in the lower part of the eyepiece.

A greater magnification (x120) revealed the face of Jupiter including the North Equatorial Belt and further separated the four moons, Callisto to the far west, Ganymede inside it and Io and Europa both close on the Eastern side with Io being closest. Taking the magnification further (x240), there were problems due to the thin veil of high cloud that was present. However, I could get glimpses of the North Temperate Belts. The South Equatorial Belt is, of course, missing at the time. Moving towards Uranus, its small disc could be discerned.

The Moon was shining brightly and at a lunation of 12.4 days. The best views I got were of the crater Schikard close to the terminator and of the high albedo of the crater Aristarchus. The rays of Tycho were also spectacular.

The cloud excluded observing any deep sky objects so I went for the doubles Gamma Andromedae (Almaak) and Beta Cygni (Albireo), both beautiful colour contrasting doubles with the former star having a separation of 10 arc seconds and the latter one 35 arc seconds.

Other objects I observed were the Perseus Double Cluster, M31 (not very impressive through the thin cloud) and the Pleiades which were rising in the East.

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Thursday, November 26, 2009

ISS and STS-129

Heavens-above.com predicted the ISS to be visible at magnitude -1.6 at 18:37:11 local time (UTC +1) at 10 deg altitude. I took the opportunity and was presented by the magnificent sight of the ISS passing through Hercules, Ophiuchus and Aquila, followed at a distance of about 10 degrees by the fainter STS-129 , the space shuttle Atlantis, at magnitude 0.4. The two craft entered the Earth's shadow and disappeared as they approached Jupiter. The sight of the two craft orbiting the Earth in close formation in the evening sky was awesome.

Monday, August 24, 2009

Starry Night

Last Saturday night the local astronomical society organized its annual boat trip. The trip is an opportunity to see a truly dark sky, a sight which has become impossible to see on our overdeveloped and light polluted island.

The trip started at sunset in the fishing port of Marsaxlokk on board the trawler Padre Pio. The night was chosen because the moon was at a lunation of only 2.3 days and set early at 20:41. It showed a lovely crescent low over the horizon at sunset but Saturn and Mercury which lay close to it were invisible in the low haze.

The port of Marsaxlokk at sunset

As the boat travelled South East, the sky grew darker and the bright stars emerged, Arcturus, Vega, Antares were visible and Jupiter appeared to dominate the sky. Slowly the light pollution faded into the distance and the twilight ended revealing the night sky in all its glory.

The most amazing sight is our own galaxy, the Milky Way visible like a bright cloud arching across the sky from Sagittarius to Cassiopeia and reflected in the sea below. The countless stars blazed in the sky in a number so large that the normally easily recognisable constellations were drowned in the myriad stars making them hard to pick out. Meteors streaked in large numbers and early on a number of satellites were visible, most notably an Iridium flare which went approximately to magnitude +4.

The visibility of deep sky objects in such a dark sky is amazing. The Lagoon Nebula (M8) and Ptolemy's cluster (M7) were clearly visible to the naked eye. The Sagittarius star cloud (M24) stood out beautifully against the rest of the Milky Way.

I had my Celestron Skymaster15x70 with me and took my chance to use them to observe the dark sky. I went through a list of favourite deep sky objects. The most notable being the M4, M13, M27, M31 which filled much of the field of view, M6, M22 and M20. I also managed to see the North American Nebula
(NGC 7000) for the first time. From my home location it isn't visible even with a 200mm Dobson. The "Gulf of Mexico" could be clearly seen.

I had prepared charts for the positions of Uranus and Neptune and I easily found them. Neptune was at mag +7.8 one third of the way between μ Cap and 42 Cap. Uranus lay below the circlet in Pisces on the extension of a line from ι Psc to λ Psc next to 20 Psc. At mag +5.7 Uranus was actually visible to the naked eye if one knew where to look.

The trip took us to a point 33.5 nautical miles to the South East of the island and drifted for two hours before heading back. At one point you could see the reflections of Jupiter and Venus in the sea on either side of the boat as dolphins darted between the waves and luminescent jellyfish glowed in the wake.

As the night wore on, more constellations rose in the East. Taurus appeared with the Pleiades, the Hyades and Mars. Auriga with its three magnificent open clusters M36, M37 and M38. Just before dawn Orion was visible with the belt stars hanging vertically over the horizon. Venus rose and then the sky lightened as the Sun put an end to the show.

Sunrise over the Mediterranean

This annual event shouldn't be missed by any local astronomy enthusiast for the unforgettable view it allows onto the universe.

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Wednesday, April 22, 2009

Harrison Schmitt

I attended a talk this evening by Harrison Schmitt, a member of the Apollo 17 mission and the last man to set foot on the moon (and the one before the last to leave). This was my first chance to hear a live first-hand account by a man who had been there. It is quite an experience when you realize that you are faced my someone who had actually set foot on the moon and experienced the gravity of another heavenly body. Schmitt is also the only scientist to have visited the moon.

The lecture was very interesting and the presentation included several anecdotes as he went through the mission touching on several aspects in a way that only one who went thorough the adventure would.

I took the photo above with my phone.

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Friday, March 20, 2009

Venus and Saturn

With Venus quickly moving towards inferior conjunction and each day setting closer to the Sun, I took the opportunity to observe its waning crescent. I could not use the telescope because it was too low for the scope from my observing location, but through my 15x70 binoculars the crescent was clearly visible in the twilight.

Later, at about 21:30 local time (20:30 UTC), I observed Saturn through my 200mm dobson telescope. I went for a magnification of x200 using my 6mm eyepiece. The rings are almost edge on but I could still see the very narrow gap between the rings and the planet. Of the moons, I could easily see Titan immediately to the East of the planet, and Rhea further out. Dione was faintly visible between them. I did manage to glimpse Tethys just outside the rings' Western tip but I couldn't see Enceladus which should have been just north of Titan.

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Sunday, February 22, 2009

Comet C/2007 N3 Lulin (2nd Post)

I had the opportunity to observe the comet through 15x70 binoculars again this evening. At 22:50 CET it was close to the 6.95 magnitude star HD101730.

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Saturday, February 21, 2009

Comet C/2007 N3 Lulin (updated)

Tonight I made my first observation of Comet Lulin as it moved Westwards through Virgo heading towards Leo and the planet Saturn which is presently near the lion's hind leg (σ Leo). I observed the comet through my 15x70 Celestron binoculars. Unfortunately there was some thin cloud but the comet was still visible. At 22:10 CET it was very close to the 7.79 magnitude star HD104484. Over a short period of time the motion of the comet relative to the star was noticeable. I was able to note hint of a tail to the West of the comet. Later on, at about 00:45 CET, I again observed the comet which had moved very close to the 6.17 magnitude star HD104055.

Not to be missed is the conjunction of the comet with Saturn on the night between the 23rd and 24th February.

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