Avid skywatchers had a chance to witness tonight’s close pairing between Jupiter and the First Quarter Moon — a nice sky event that kicked off the celebration of the National Astronomy Week 2013 in the Philippines. If you look closely at Jupiter in this image, you’ll also see a hint of its 4 Galilean moons.
During the closest approach, Jupiter and the Moon were 0.5 degree apart. For comparison, the angle covered by the diameter of the full moon is about 31 arcmin or 0.5 degree.
Astronomers use angular measurements to describe the apparent size of an object, or the distance between them. Knowing how to measure angular distance is an essential skill to finding your way around the sky.
Mercury and Mars less than a degree apart after sunset on February 8th
Mercury is well placed in the evening twilight this month, but spotting it won’t be easy. The closest planet to the sun will be low in the west-southwest horizon and will be a bit washed out by twilight’s glow. Binoculars may be needed to find it in the glare of twilight.
On February 8, Mercury will be less than 1 degree from pale orange Mars. The sky won’t be dark enough to see them until they’re just setting, so you’ll need a view to the west that is unobstructed and free from light pollution. They should be visible half an hour after sunset. During the event, Mercury will be about eight times brighter than Mars.
On February 11, a thin crescent moon, one day past new moon will join Mercury and Mars in the twilight sky.
Mercury’s visibility will continue to improve until February 16, when it reaches its greatest eastern elongation from the sun and appears 11 degrees above the west-southwestern horizon. Afterward it will drop back toward the sun, disappearing into bright twilight by the end of the month.
Moon and Jupiter less than 1 degree apart on February 18
Another close conjunction between Jupiter and the Moon, joined by Aldebaran and the Hyades to the left and the Pleiades to the right, will occur on February 18th. At the moment of closest approach, the Moon will be at mag -11.9, and Jupiter at mag -2.4, both in the constellation Taurus.
The pair will be a little too widely separated to fit comfortably within the field of view of a telescope, but will be visible to the naked eye or a through pair of binoculars. To some parts of the world like in the southern Indian Ocean, Southern Australia and Tasmania, this will be viewed as an occultation event where in the Moon will actually pass in front of Jupiter.
Other events this month:
* FEBRUARY 1: Moon ~10 degrees above Spica (in the constellation Virgo)
* FEBRUARY 4: Moon ~7 degrees below Saturn in the eastern sky
* FEBRUARY 5: Moon by “Scorpion’s Crown” before dawn
* FEBRUARY 8: Mercury & Mars in tight conjunction in the western sky shortly after sunset (about 0.4 degrees apart)
* FEBRUARY 9: Moon ~8 degrees above Venus before dawn
* FEBRUARY 11: Thin moon near Mercury & Mars after sunset
* FEBRUARY 16: Mercury in greatest eastern elongation (11 degrees above WSW horizon)
* FEBRUARY 18: Moon and Jupiter less than 1 degree apart
* FEBRUARY 25: Moon and Regulus (in the constellation Leo) ~10 degree apart
# # #
* FEBRUARY 3: Third Quarter Moon at 21:57
* FEBRUARY 10: New Moon at 15:20
* FEBRUARY 18: First Quarter Moon at 04:31
* FEBRUARY 26: Full Moon at 04:26
# # #
Measuring angles in the night sky
The post made reference to angular separations of objects in the night sky, like the moon and planets. If you’re wondering how to measure or approximate these angular distances when you do skygazing, below is a simple guide that will teach you how. The good news is you don’t need any device. You only have to use your own hand. 🙂
Hold your fist at arms length, and:
- Extend your little finger; it’s width is approximately 1 degree.
- Extend your three middle fingers (without the little finger); thats about 5 degrees.
- A clenched fist (thumb to little finger) is about 10 degrees.
- From the tip of the little finger to the tip of the thumb, an extended hand with fingers and thumb splayed subtends about 20 degrees.
Thats it! Those measurements are approximations but are accurate enough to locate the objects in the sky .
Last January 22, 2013, the waxing gibbous moon appeared near the bright planet Jupiter in the evening sky.
As seen from the Philippines, the Moon and Jupiter made a close approach within roughly 5 degrees of each other. Some folks in the Southern Hemisphere, however have seen Jupiter completely disappear behind the moon – an occultation.
During this event, the Moon was at mag -12.3, and Jupiter at mag -2.6, both in the constellation Taurus.
The sky condition was mostly cloudy. When the clouds parted, I was able to a couple of wide angle images which includes the two famous star clusters in Taurus — the Hyades and the Pleiades. In another image, the moon was shot at two different exposures to show the amount of separation between it and Jupiter.
Images were taken from Bulacan, Philippines around 8:40 – 9:00 pm PHT.
A 6% illuminated waning crescent moon and the planet Venus were in a close conjunction low in the southeast just before sunrise last 10 January 2013.
The waning crescent which looks like a thin “smile” on the sky, tilted a bit to the right. The soft glow on the dark side of the moon is called the Earthshine.
I always love taking pictures of a thin crescent moon, especially when it’s also nearby another bright objects like the planet Venus. It just makes my day complete. 🙂
On my way home after attending tonight’s Christmas Day Mass, I saw a faint ring or halo around the Moon. Lunar halos often result when moonlight enters randomly- oriented hexagonal ice crystals in wispy cirrus clouds. Refraction of light produces a 22 degree ring or halo around the Moon. In order for a halo to appear, the Moon must be at least 22 degrees above the horizon. Interestingly, Jupiter was also positioned inside the 22 degree halo on this night near the waxing gibbous moon.
Lunar halos usually indicate that a bad weather is on it’s way. In the Philippines, a new tropical depression is expected to bring heavy rains across central part of the country in the next few days.
Image taken using hand-held Canon Powershot SX40 HS.
Merry Christmas, folks!
A few minutes after sunset last October 18, 2012, two reddish objects were found near the waxing crescent Moon (12% illuminated) in the western sky. These two bright red objects were actually the planet Mars, and the bright star Antares in the constellation Scorpius. Mars was about 2 degrees to the upper left from the Moon, and Antares about 4 degrees to the lower left from Mars.
Mars and Antares are often mistaken for each other because of their similarity in appearance. In fact, the name Antares means “Rival of Mars” in Greek.
All photos were taken using Canon Powershot SX40 HS. Some if the images were blurry. My camera got out of focus and i didn’t notice till it was too late! 😦
Click on the images to see larger versions.
The sky was extra clear that night. Amazed by the beauty of the starry night sky, I took my camera out again and snapped this photo while walking home:
This month, weather conditions permitting, skywatchers will be treated to the Perseid meteor shower, several planet conjunctions, a “blue moon” and a relatively rare lunar occultation of Jupiter (visible for some parts of the globe).
August 7-14: Spica, Saturn and Mars at Dusk
The planets Saturn and Mars and the star Spica are close together in the first half of the month, low above the western horizon at dusk. They will form a triangle on the 7th an hour after sunset. Saturn will be the top of the triangle, while Mars will be on the lower right corner. Each side of the triangle is about 5 degrees. On the 14th, they will form an almost straight line: Saturn topmost with Mars lying between Saturn and Spica.
August 12: Occultation of Jupiter by the Moon
For Philippine observers, the waning crescent Moon will pass in front of Jupiter and its moons during a relatively rare event called occultation on the morning of August 12. In astronomy, an occultation occurs when one object is hidden by another larger object that passes between it and the observer. Prospects and timings for the event vary with location.
The event takes place while Jupiter and the Moon are low in the sky during the wee hours of the morning.
|2012 Aug 12 02:43||Occultation disappearance of Jupiter (Mag -2.2)|
|2012 Aug 12 03:16||Occultation reappearance of Io (Mag 5.5)|
|2012 Aug 12 03:17||Occultation reappearance of Jupiter (Mag -2.2)|
|2012 Aug 12 03:18||Occultation reappearance of Europa (Mag 5.7)|
|2012 Aug 12 03:20||Occultation reappearance of Callisto (Mag 6.1)|
|2012 Aug 12 03:32||Occultation reappearance of Ganymede (Mag 5.0)|
August 11, 12: Perseid Meteor Shower
The Perseids is one of the best annual meteor showers.
The best time to watch for Perseids is between midnight and dawn. This is when the shower’s radiant located between the constellations Cassiopeia and Perseus, lies highest in the northeast sky.
By the 12th, the moon will only be 25% illuminated and not nearly as intense as when near its full phase. This will allow fainter meteors to be seen as long as the moon lies outside your field of view.
Tip: Find a safe dark location with clear skies in the early morning hours in order to see the shower. This year, the shower peaks on a weekend so it’s more convenient to stay up late.
August 14: A line of planets along with a thin, waning, crescent Moon before dawn
Before dawn on the morning of the 14th August the planets Mercury, Venus and Jupiter and the Moon will line up in the eastern sky. Look for A very thin crescent Moon to the upper right of Mercury an hour before sunrise in the northeast. Venus is to the upper right of the Moon, and a few degrees above them is Jupiter.
August 22: Waxing Crescent Moon joins Saturn, Mars and Spica
On the evening of the 22nd, a waxing crescent Moon, Mars, and Saturn will all lie within a circle just 6° in diameter.
August 31: Blue Moon (second full moon of August)
On the 31st, we will be able to witness a Blue Moon, the term given to the second full Moon in a calendar month. But don’t expect it to be blue — the term has nothing to do with the color of the moon. [Origin of the term blue moon]
Eastern sky at 4:00 am local time. Manila, Philippines. Image: Stellarium
Philippine sky observers will have a great chance to see all of the three brightest objects of the night sky in close proximity to each other this weekend (weather permitting). On the morning of July 15th, the waning crescent moon will join the very bright “stars” Jupiter (upper) and Venus (lower) to form a nice celestial grouping, along with two prominent open star clusters — the Pleiades and the V-shaped Hyades — in the constellation Taurus.
Venus has reached its greatest illuminated extent in Earth’s sky last July 12. Thus, it appears so dazzling now as a “morning star” in our predawn sky, near Jupiter.
Meanwhile, in other parts of the globe, this celestial grouping event will be viewed as an occultation of Jupiter by the moon. An occultation is an event in which a celestial body covers another, farther away object, such as when the moon covers a star or a planet or when a planet or an asteroid covers a far away star. For this event, the moon will cover Jupiter for about an hour (the exact time and durtaion of the occultation is dependent on the observer’s location). View the visibility map and timings of this event from IOTA.
Seeing Jupiter’s occultation is possible with the naked eye, but the look through a telescope, even using a small magnification, is marvelous. At first, two of Jupiter’s large moons (Io and Europa) will disappear behind the moon, then Jupiter will disappear and then the other two moons (Ganymede and Callisto).
Places close to the southeast will witness a ‘grazing occulation’ when Jupiter and its moons will skim the edge of the Moon. This will be well worth seeing through a telescope and Jupiter’s moons may be seen blinking in and out of view as they pass behind the lunar mountains. Further north and west a very close conjunction will be seen.
Don’t worry because even though we won’t be seeing this event in the Philippines this weekend, we are still lucky enough to see a very rare version of such an event next month, during the morning of August 12, 2012. That will be surely worth getting up to see!
Moon occulting Jupiter with its moons. Image: Stellarium
Observing occultations can also contribute to science. During the 80’s, Uranus occulated a distant star. Photos of the events showed that just before and after the occultation the star blinked several times. The theory then was developed that Uranus has a set of rings (like Saturn). When Voyager 2 reached Uranus it detected and photographed the predicted rings.
Don’t miss this event. Clear skies!
Related link: List of Notable Celestial Events in 2012
This morning I took the chance to image the close pairing of Mercury and the thin waning crescent Moon.
Mercury an inner or inferior planets like Venus, always appear close to the sun in the sky due to their low elongation (angular separation from the sun as (angular separation from the sun as viewed from earth), hence it’s always interesting to spot this tiny elusive planet near other brighter objects such as the moon.
Neither Mercury or Venus ever appears very far from the sun and consequently never far above the horizon (except Venus at maximum elongation). Both can only appear in the west in the evening and in the east in the morning and only for a short amount of time.
Inferior planet elongation. Image credit: wapi.isu.edu
In the case of Mercury, take note that it will always be located in the sky no more than 28 degrees from the Sun.
After checking Stellarium, I prepared my trusty point-and-shoot camera and tripod and went outside before 4:00 AM. A view of Scorpius in the southwest greeted me as I set up.
The eastern horizon was fortunately clear that time. In just a little while, a thin golden arc of light began to appear above the horizon. I took my 2-inch Galileoscope out and pointed at the moon.
Thin crescent Moon rising at around 4 AM
It didn’t take long before the twilight began to creep out and push the darkness away. The sky turned blue and soon I noticed the earthshine, the ghostly illumination of the lunar dark side.
Mercury should be located only a few degrees away from the moon. I searched the area just below the lower limb of the moon where this planet was suppose to lie and found its faint shine.
It was barely visible in the images fo it lies above the glow of the rising Sun so I used the dodge tool in Photoshop during the post-editing to make it more visible.
After a few minutes of imaging, the light from the two objects were eventually washed out in the solar glow.
The planet Saturn formed a cosmic triangle with the star Spica in Virgo and the Waning Gibbous Moon last night, 7 April 2012.
This image is composed of two images that have been overlapped to create a composite: one underexposed image of the moon to show the lunar features, and one overexposed to make Saturn and Spica more visible. (Sorry for the bad editing. I still lack skills in using Adobe Photoshop).