In The Sky This Month – 2009 April

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of April 2009. The month sees the return of the borderline major meteor shower, the Lyrids. The highlight of the month is the lunar occultation of Venus right before dawn on April 22.

Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment. I’ll post them here.

Planets

Mercury – This month brings us the best opportunity of the year to observe Mercury in the evening sky (for Northern Hemisphere observers). Mercury will be at its highest on April 26, though even then it will be low in the western sky 30-60 minutes after sunset.

The Moon will also located just above Mercury on the evening of April 26. The image below shows what the scene will look like from North America. Note that the Pleiades open star cluster will be located between Mercury and the Moon. It will be a great sight via your eye or binoculars. In a telescope, Mercury will appear as a fat crescent with ~36% of its disk illuminated.

mercury_moon_apr26

Map of the Moon-Mercury-Pleiades conjunction on the evening of April 26. Map made with Stellarium.

Saturn – Saturn is the only planet visible in the evening sky. By the end of twilight, Saturn is high in the southeast under the eastern part of the constellation of Leo.

This year Saturn is dimmer than usual. At magnitude +0.6 to +0.7, there are at least 11 stars that are brighter than it. The reason is that the rings of Saturn contribute a lot  to the brightness of Saturn. But this year, is a ring plane crossing year meaning that the rings are nearly edge-on. As a result, the rings are reflecting much less light in the Earth’s direction this year. Saturn’s appearance through a telescope will match the below image taken by Bob Lunsford on March 28. Note the small dark spot near the top edge of Saturn’s disk, this is a shadow cast by Saturn’s largest moon, Titan.

saturn_20090328_1007_lunsford

Image of Saturn by Bob Lunsford from 2009 March 28. Titan's shadow seen near top.

The Moon will pass a relatively distant 5.5 degrees to the south of Saturn on the evening of April 6.

Venus – After spending the past few months dominating the evening sky, Venus will now spend the rest of the year as a morning object. If you live south of the Equator, Venus will appear to rocket higher and higher every morning. In fact it should be an easy sight by the 2nd week of April if you have a clear eastern horizon. Venus will reach its highest in late May.

For those of us north of the Equator, Venus will take a little longer to gain altitude. Though it is already visible for observers with a clear eastern horizon, Venus will slowly climb higher every night. For  northern observers, Venus won’t reach its highest till August. Regardless of where you are observing, Venus will be at its brightest on April 29 though it is always a very bright object.

For binocular and telescope users, Venus will start the month as a large thin crescent, 59″ across and only ~2% illuminated. By mid-month, it will have shrunk to ~50″ across but it will also become a fatter crescent with ~12% of the disk illuminated. By the end of the month, it is 39″ across and 25% illuminated

Venus is also involved in the coolest event of the month. On the morning of April 22, the Moon will occult (or pass in front) of Venus for observers in most of North America. The below map from the International Occultation Timing Association (IOTA) shows where the occultation will be visible. Times for the beginning and end of the occultation can be found at IOTA’s site. I’ll write more about this as the date draws closer.

0422venus1

The following diagram gives a good representation of what the occultation will look like right before the Moon passes in front of Venus on the morning of April 22. Note that Mars will be located nearby as well. For those with binoculars or a telescope, Venus will appear as a thin crescent similar to, but much smaller than, the Moon.

venus_moon_mars_april22

The Moon, Venus and Mars just before the start of the occulatation of Venus on the morning of April 22. Sky map produced with Stellarium.

Jupiter – Jupiter rises a few hours before sunrise. Other than Venus, it is the brightest “star” in the morning sky at magnitude -2.2. Due to Jupiter’s location in the southern constellation of Capricornus , it never gets very high this year.

Mars – Mars can be seen very low in the eastern sky all month long. At magnitude +1.2, it is only as bright as some of the brighter stars. Venus will pass a distant 5.5 degrees to the north of Mars on April 24. As a result, Mars will be located just below the spectacular Moon-Venus occultation.

Meteors

The month of March experiences no major showers and only a few minor ones. It continues the annual lull in meteor activity from mid-January to mid-April.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During April, 8 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Lyrids (LYR)

April brings the first major meteor shower since the Quadrantids in early January. The Lyrids are produced by Comet Thatcher, a comet on a ~400 years orbit that has only been observed in 1861. The Lyrids, on the other hand, can be seen every year.

The radiant is located between the constellations of Lyra and Hercules. Though the radiant rises during the evening, the best time to see Lyrids is after 11 pm when the radiant is high in the sky.

The shower is active from April 16 to 25 with a peak on the morning of April 22. The shower only shows good levels of activity on the night of the peak. Even then, this is the most minor of the major showers with a peak rate of ~15-25 meteors per hour.

Though there are no predictions on enhanced activity, the Lyrids have been known to put on grand displays. The 1st great display goes back almost 25oo years while the last happened in 1982. So you never know, this year could be the next good display.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors.

Pi Puppids (PPI)

The Pi Puppids are usually a very low activity shower. In 1977 and 1982, the shower put on a good display with up to 60 meteors per hour being observed. This shower radiates from the far southern constellation of Puppis and can not be seen from most of North America and Europe.

We now know that the Pi Puppids are created by Comet 26P/Grigg-Skjellerup. P/G-S is a small Jupiter family comet that orbits the Sun once every 5.3 years.

There are no predictions for enhanced material this year. The shower is active from April 15-28 with a peak on April 23. At its best we should expect 1-2 meteors per hour with even that number being optimistic for northern observers.

Eta Aquarids (ETA)

The Eta Aquarids are a major shower, especially for southern hemisphere observers, when they peak on May 5. During the month of April, the shower can be considered a minor shower.

The ETA were produced by Comet Halley which also gives us the Orionids in October. Models suggest that the ETA were released by Comet Halley no later than 837 AD. The Orionids are easy to see because the particles are hitting the Earth from the anti-solar direction. This means the meteor shower can be seen in the middle of the night. The ETA are produced by meteoroids moving outbound from the Sun, as a result the radiant is located relatively close to the Sun. This means that the ETA radiant is only visible for an hour or so before twilight.

The shower spans from April 19 to May 28 with a peak around May 5 with a maximum ZHR of ~60. The last week of April will see some low activity (ZHR < 10) from the ETAs.

Additional information on these showers and other minor showers not included here can be found at the following sites: Robert Lunsford’s Meteor Activity Outlook, Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2008 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V < 8.0)

None

Small Telescope Comets (V < 10.0)

Comet C/2009 E1 (Itagaki)

This recently discovered comet was found by amateur astronomer Koichi Itagaki of Yamagata, Japan. Comet C/2009 E1 (Itagaki) is a long-period comet which will come within 0.60 AU of the Sun at perihelion on April 7. It is also periodic in that it returns once every ~250 years according to the latest orbit.

This is the 1st comet to bear Koichi Itagaki’s name but it is not his 1st discovery. Back in 1968, he was a co-discoverer of Comet Tago-Honda-Yamamoto. Due to the rule that only the 1st 3 discoverers can have their name attached to a comet, his name was left off. Only a few months ago, he also re-discovered long-lost comet Giacobini.

The comet is located in the evening sky north of the constellation of Aries. As the month progresses the comet will move north of the Sun as it travels through Triangulum, northern Pisces and Andromeda. Only observers with a clear view of the northwestern horizon in the evening and northeastern horizon in the morning will be able to see the comet. By May the comet will only be visible in the morning sky and will be much easier to see.

At magnitude ~8.0 to 8.5, the comet is bright enough to be seen in a reasonably sized backyard telescope. Having said that, I was just barely able to see it from my backyard in Tucson with my 12″ telescope due to the city lights and the bright twilight.

A finder chart for Comet Itagaki can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany).

Comet C/2009 F6 (Yi-SWAN)

A new comet has been discovered that should be the brightest comet in the sky this month. Comet C/2009 F6 (Yi-SWAN) is a long-period comet which will pass within 1.27 AU of the Sun on May 8. The comet is currently around magnitude 8.5 making it bright enough to be seen in small telescopes. Right now the nearly Full Moon will make observing the comet difficult but in a few days the Moon will not be a problem for evening observers. The comet is located north of the Sun. For southern hemisphere observers, you are out of luck. For northern observers, the comet can be observed in both the evening and morning sky.

Currently the comet is located in Cassiopeia. It is moving to the east and will enter Perseus by mid-month. The comet should continue to brighten as it approaches perihelion and may be as bright as magnitude 8.0.

On the morning of April 21, I was able to observe Yi-SWAN with 30×125 binoculars. My observing location isn’t too dark with a limiting magnitude of ~+5.5. Even then, the summer Milky Way was faintly visible. The comet was barely visible as it was large and diffuse. Interestingly, the comet was not visible during multiple attempts to observe it during the evening hours. The darker morning sky most definitely helped.

yi-swan4

The comet was found by Dae-am Yi of Yeongwol-kun, Gangwon-do, South Korea on March 26. He noticed the obvious blue-green glow of a comet on 2 images he took with a Canon 5D digital camera and a 90-mm f/2.8 lens. The other discoverer was Robert Matson of Irvine, CA. Mr. Matson found the comet on a series of images taken with the SWAN instrument on the SOHO (Solar Heliospheric Observatory) spacecraft starting on March 29. The SWAN insturment images the entire sky for solar Lyman-alpha particles that are backscattered off of neutral hydrogen atoms. In this way, SWAN can monitor the activity of the far-side of the Sun. This instrument is also excellent at detecting the glow of hydrogan in the extended coma of comets.

Comet C/2007 N3 (Lulin)

Comet Lulin was discovered by the Lulin Sky Survey in Taiwan on 2007 July 11. At the time the comet was located beyond the orbit of Jupiter. The comet will be closest to the Sun on 2009 January 10 at 1.21 AU from the Sun. It will be closest to Earth in late-February when it will be only 0.41 AU from us.

The comet is fading after its closest approach to Earth in late February. It is a evening object and spends all of April moving westward through western Gemini. The comet starts the month around magnitude 8.5 and should fade to magnitude 10.0 or fainter by the end of the month.

A finder chart for Comet Lulin can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet C/2006 W3 (Christensen)

This comet was discovered over 2 years ago on 2006 November 18 by Eric Christensen of the Catalina Sky Survey north of Tucson. At the time the comet was located at 8.7 AU from the Sun which is nearly the distance of Saturn. The comet continues to move closer to the Sun and Earth and is currently 3.8 AU from the Sun and 3.4 AU from the Earth.

The comet is currently around magnitude 9.5 and will slowly brighten during the month.  It is moving near the border of Lacerta and Pegasus.  The comet is best seen in the early morning. I was able to observe the comet visually with my backyard 12″ reflecting telescope back in November. Being small and condensed, the comet was fairly easy to see.

The comet will continue to brighten as it approaches perihelion at a still rather distant 3.12 AU from the Sun on 2009 July 6. At that time, the comet will be 8th magnitude and visible in many smaller backyard telescopes and even binoculars from dark sites. Christensen should remain bright enough to see in modest sized backyard telescopes for all of 2009.

On the morning of April 21, I was able to observe this comet with both 30×125 binoculars and a 12″ dobsonian. The comet was much easier to see in the 12″. Observation was made under a moderately light polluted sky with a limiting mag of ~+5.5.

A finder chart for Comet Christensen can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 10.0)

(1) Ceres

Ceres is the biggest asteroid in the Main Belt with a diameter of 585 miles or 975 km. It is so big that it is now considered a Dwarf Planet. Classified as a carbonaceous (carbon-rich) Cg-type asteroid, there are suggestions that it may be rich in volatile material such as water. Some even propose that an ocean exists below its surface. Ceres is one of two targets for NASA’s Dawn spacecraft which is scheduled to visit it in 2015. Last month Ceres was at opposition (at its closest to the Earth and at its brightest). This month Ceres will fade from from magnitude 7.4 to 8.0 as it ends is retrograde motion just north of Leo. If you are observing Saturn with a telescope or pair of binoculars, try your hand at finding Ceres with one of the finder charts linked below.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Ceres from Heavens Above.

(2) Pallas

Pallas is also a carbonaceous asteroid though with a slightly bluish B-type spectrum. Due to its high inclination (tilt of its orbit with respect to Earth’s orbit) of 34 degrees it is a difficult target for future spacecraft missions. Pallas is large with dimensions of 350x334x301 miles or 582x556x501 km. This month it continues moving north, leaving the constellation of Orion and entering Monoceros. It fades from  magnitude 8.7 to 8.9 over the course of the month.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Pallas from Heavens Above.

(8) Flora

Flora is a large asteroid roughly 136x136x113 km in dimension. It is innermost large asteroid in the Main Belt. As a result, it can get bright enough for backyard observers with modest sized telescopes and binoculars. Flora is a stoney S-type asteroid and also the largest member of the Flora family. This family was created when a large impact occured on Flora. The other family members are pieces of Flora that were thrown off by the impact.

Flora starts the month at magnitude 10.0. It reaches its maximum brightness on April 22 at magnitude 9.8. By the end of the month, it has slightly faded to 9.9. Flora and Irene provide us with a 2-for since both objects are located within 5 degrees of each other.

Since there I have not been able to find a nice star chart showing the position of Flora, here is one I made with the C2A program. It also shows the position of Irene.

flora_irene_april

(14) Irene

Irene was discovered by John Russel Hind in 1851, being only the 14th asteroid known at the time (if you are wondering ~400,000 asteroids have been discovered to date, we’ve come a long way). It is an S-type asteroid with a stoney or silicate composition. Its takes 6.3 years to orbit the Sun.

This month Irene will brighten from magnitude 9.2 to a maximum of 8.9 on April 24 as it retrogrades through western Virgo. Remember Flora is located within 5 degrees of Irene.

(15) Eunomia

Discovered in 1851, Eunomia is one of the largest stoney S-type asteroids. Its dimensions are roughly 357×255×212 km. Similar to Flora, Eunomia is also the parent body of its own family.

Eunomia spends all of April in the constellation of Corvus, just to the south of Virgo. With opposition on April 2, the asteroid is as bright as it’s going to get this year at magnitude 9.8. As the month progresses it will fade to 10.0. This year Eunomia is at aphelion, its furthest from the Sun making this one of its faintest oppositions. When at perihelion, it can get as bright as magnitude ~8.

Since there I have not been able to find a nice star chart showing the position of Eunomia, here is one I made with the C2A program.

eunomia_april

(29) Amphitrite

Discovered in 1854, Amphitrite was the 29th asteroid to be discovered. Similar to Euterpe, Amphitrite is also a stoney S-type asteroid. With an average diameter of  127 miles (212 km) it is bigger than Euterpe though its further distance from the Earth and Sun keeps it from getting as bright.

Amphitrite fades from magnitude 9.5 to 10.1 this month. It spends the entire month in eastern Virgo not far from Saturn. If you are observing Saturn, take a short star-hopping trip to Amphitrite

Since there I have not been able to find a nice star chart showing the position of Amphitrie, here is one I made with the C2A program.

amphitrite_april

The Past Week in Pictures

Yet another night of thick clouds here in Arizona. I wouldn’t mind if it would actually rain. Not only are the clouds shutting down the meteor survey being conducted by myself and Bob Lunsford but also the professional Near-Earth asteroid surveys located nearby.

While we wait for the sky to clear, here are a few nice images from the past week.

Photographer John Rav took a great picture of Venus setting behind Agathla (also called El Capitan), a volcanic plug in Monument Valley, Arizona. The photo is a ~15 minute time-lapsed photo so Venus and the stars are trailed as they move across the sky. Venus is the brightest star in the middle of the picture. Also note the Square of Pegasus to the right of Agathla and Diphda (the brightest star in Cetus the whale) at the far left. More images by John can be found at his Flickr site. Thanks for sharing your photos, John!

johnrav_venus_trail

The next 2 planetary images were taken with my 12″ Dobsonian telescope on the evening of February 26. The camera used was a DMK 41AF02.AS by ImagingSource. Recently I purchased a tracking mount which allows me to image objects for more than a fraction of a second. Each planetary image below is actually a combination of 100-200 very short exposures (usually less than 0.1 seconds).  The images are close to what the view of Venus and Saturn would be like in a small backyard telescope.

venussaturn_20090226

The next image was taken with the same planetary video camera as the Venus and Saturn images above. But, instead of observing through a telescope I used a small wide-field lens (Computar 4mm f/1.2). This is the same type of lens I use for my meteor observations.

lulin_in_leo_20090226The comet is the slightly elongated fuzz below Regulus. It is more obvious in the 2x magnified view in the bottom right. It is interesting to note that the largest Main Belt asteroid (and now dwarf planet) Ceres is also visible in the image. I wasn’t aware of this until after the image was taken. So it was a nice surprise. I haven’t looked at Ceres through a telescope since 1992-93. It’s probably time to pay it a visit once again.

I have recently purchased a larger lens, the Computar 12mm F1.2. Hopefully this lens will allow wide-field images that go even fainter.

In The Sky This Month – March 2009

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of March 2009. This month sees the end to Venus’ reign over the evening sky. Also Comet Lulin should continue to be bright enough for easy evening observation.

Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment. I’ll post them here.

Planets

Venus has been putting on quite a display for the past few months in the evening sky. Unfortunately, the show comes to an end this month. At the beginning of the month, Venus is still riding high in the western sky after sunset. As the month progresses, it will appear lower and lower in the sky. Most people will have a hard time seeing it by mid-month. On March 27, Venus will pass between closest to the Sun. After that date, it will become a morning object. Early hour risers will witness Venus in all of its glory for most of the rest of the year.

venussaturn_200902261

This month Saturn will at opposition. The exact date being March 8. Opposition is when a planet (or comet or asteroid) is located opposite the direction of the Sun. On this date, Saturn will be closest to Earth and at its brightest. It rises at sunset and by 9pm is high enough to be easily seen. Even at its brightest, Saturn is not as brilliant as Venus or Jupiter. Still at magnitude +0.5, it is brighter than all but the 9 or 10 brightest stars.

saturn_allsky_09452

The evening sky for March 15 at 9:45 pm. Chart produced with the Stellarium planetarium program.

This opposition is actually one of Saturn’s dimmest. The reason is that the rings of Saturn contribute a lot  to the brightness of Saturn. But this year, is a ring plane crossing year meaning that the rings are nearly edge-on. As a result, the rings are reflecting much less light in the Earth’s direction this year.

Jupiter and Mars are located near each other low in the early morning sky. As the month progresses Jupiter will become easier and easier to see. At magnitude -2.1, Jupiter is brighter than any star in the sky.  Mars on the other hand will only be visible to those with a clear view of the southeastern horizon. At magnitude 1.2, Mars would just crack the Top 20 in brightest stars in the sky.

march_sunrise

Early morning sky right before dawn on March 15. (produced with Stellarium)

Mercury is still visible low in the east just before dawn. Due to the angle of the ecliptic with the morning eastern horizon this month, Mercury is a very difficult object to observe from the Northern Hemisphere but an easy object from the Southern Hemisphere. It will be lost to Northern observers a few days into the month. Southern observers will be able to follow it till a bit past mid-month.

Meteors

The month of March experiences no major showers and only a few minor ones. It continues the annual lull in meteor activity from mid-January to mid-April.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During November, six (6) or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

None.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors.

Delta Leonids (DLE)

The Delta Leonids are another minor shower with a period of activity from February 15 to March 10. Near its February 25 peak, rates may reach a paltry 2 per hour.

Gamma Normids (GNO)

This shower is best from the Southern Hemisphere since it radiates from the southern constellation of Norma. Observers north of +40 deg North will not be able to see any GNOs. Then again it is such a minor shower that there is doubt whether it even exists!

The shower spans from Feb 25 to March 22 with a peak around March 13 with a maximum ZHR of 4.

Additional information on these showers and other minor showers not included here can be found at the following sites: Robert Lunsford’s Meteor Activity Outlook, Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2008 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

Comet Lulin starts the month as a barely naked eye comet at magnitude 5. More on this comet can be found in the next section.

Binocular Comets (V < 8.0)

Comet C/2007 N3 (Lulin)

Comet Lulin was discovered by the Lulin Sky Survey in Taiwan on 2007 July 11. At the time the comet was located beyond the orbit of Jupiter. The comet will be closest to the Sun on 2009 January 10 at 1.21 AU from the Sun. It will be closest to Earth in late-February when it will be only 0.41 AU from us.

The comet is currently around magnitude 5.2 which makes it an easy object for binoculars and small telescopes from a dark sky. From a dark rural moon-less sky, it can even be seen with the naked eye. Over the course of the month, the comet will fade from naked eye view but still be bright enough for binocs/small telescopes. By the end of the month, Lulin will be close to 7th magnitude.

After a few months as a morning object, Lulin spends all of March visible in the evening. Due to its retrograde orbit, the comet is moving in almost the exact opposite direction as the Earth. As a result, it is rapidly moving to the west every night. Over the course of the month, Lulin will start the month in western Leo, cross Cancer and end in the middle of Gemini.

A finder chart for Comet Lulin can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Small Telescope Comets (V < 10.0)

Comet C/2006 W3 (Christensen)

This comet was discovered over 2 years ago on 2006 November 18 by Eric Christensen of the Catalina Sky Survey north of Tucson. At the time the comet was located at 8.7 AU from the Sun which is nearly the distance of Saturn. The comet continues to move closer to the Sun and Earth and is currently 3.8 AU from the Sun and 3.4 AU from the Earth.

The comet is currently around magnitude 9.7 and will slowly brighten during the month.  It is moving near the border of Lacerta and Pegasus.  The comet is best seen in the early morning. I was able to observe the comet visually with my backyard 12″ reflecting telescope in November. Being small and condensed, the comet was fairly easy to see.

The comet will continue to brighten as it approaches perihelion at a still rather distant 3.12 AU from the Sun on 2009 July 6. At that time, the comet will be 8th magnitude and visible in many smaller backyard telescopes and even binoculars from dark sites. Christensen should remain bright enough to see in modest sized backyard telescopes for all of 2009.

A finder chart for Comet Christensen can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet 144P/Kushida

Comet Kushida was discovered by Japanese amateur astronomer Yoshio Kushida back on 1994 January 8. With an orbital period of 7.6 years, this year marks its 3rd appearance since discovery.

The comet was not expected to get brighter than magnitude 10 or 11 but recently observers have estimated it is as bright as magnitude 9.1. With perihelion this January 26 at 1.44 AU from the Sun, the comet should start to rapidly fade. The comet starts the month near the border of Taurus and Orion before moving across the “club” of Orion and into Gemini.

A finder chart for Comet Kushida can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 10.0)

(1) Ceres

Ceres is the biggest asteroid in the Main Belt with a diameter of 585 miles or 975 km. It is so big that it is now considered a Dwarf Planet. Classified as a carbonaceous (carbon-rich) Cg-type asteroid, there are suggestions that it may be rich in volatile material such as water. Some even propose that an ocean exists below its surface. Ceres is one of two targets for NASA’s Dawn spacecraft which is scheduled to visit it in 2015. Last month Ceres was at opposition (at its closest to the Earth and at its brightest). This month Ceres will fade from from magnitude 6.9 to 7.4 as it moves into Leo Minor, just north of Leo. If you are observing Saturn with a telescope or pair of binoculars, try your hand at finding Ceres with one of the finder charts linked below.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Ceres from Heavens Above.

(2) Pallas

Pallas is also a carbonaceous asteroid though with a slightly bluish B-type spectrum. Due to its high inclination (tilt of its orbit with respect to Earth’s orbit) of 34 degrees it is a difficult target for future spacecraft missions. Pallas is large with dimensions of 350x334x301 miles or 582x556x501 km. This month it continues moving north, leaving the constellation of Lepus and entering southern Orion. It fades from  magnitude 8.4 to 8.7 over the course of the month.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Pallas from Heavens Above.

(4) Vesta

Though not as large as Ceres, Vesta is more reflective making it the brightest asteroid in the Main Belt. Vesta is peculiar in that it appears to have evidence of volcanism on its surface. Similar to the Moon, Vesta may be covered with large expanses of frozen lava flows. It is classified as a V-type asteroid and is the only large asteroid with this classification. Many of the smaller V-type asteroids are chips of Vesta blasted off it by past asteroid and comet impacts. Vesta is similar in size to Pallas with dimensions of 347x336x275 miles or 578×560×458 km. Vesta will also be visited by NASA’s Dawn spacecraft which will arrive in 2010. On October 30, Vesta was at opposition (directly opposite from the Sun in the sky) and at its brightest. This month Vesta is an evening object moving through Aries before entering Taurus near the end of the month. It will fade from magnitude 8.3 to 8.5.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Vesta from Heavens Above.

(14) Irene

Irene was discovered by John Russel Hind in 1851, being only the 14th asteroid known at the time (if you are wondering ~400,000 asteroids have been discovered to date, we’ve come a long way). It is an S-type asteroid with a stoney or silicate composition. Its takes 6.3 years to orbit the Sun.

This month Irene will brighten from magnitude 9.9 to 9.2 as it travels through Virgo. Next month it will reach its brightest on April 21 at magnitude 8.9.

(27) Euterpe

Euterpe was the 27th asteroid discovered when it was first seen in 1853. It is an S-type asteroid with a stoney or silicate composition. With a diameter of 58 miles (96 km) it is much smaller than Ceres, Pallas or Vesta. The reason it can get as bright as them is due to its orbit which brings it closer to the Sun and Earth. This month Euterpe will be roughly 1 AU from Earth and 2 AU from the Sun.

This month Euterpe is located in Cancer not far to the east of the Beehive Star Cluster. It starts the month at magnitude 9.7 and fades to 10.5 making this an object for advanced observers.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Euterpe from Heavens Above.

(29) Amphitrite

Discovered in 1854, Amphitrite was the 29th asteroid to be discovered. Similar to Euterpe, Amphitrite is also a stoney S-type asteroid. With an average diameter of  127 miles (212 km) it is bigger than Euterpe though its further distance from the Earth and Sun keeps it from getting as bright.

Ampitrite reaches it brightest for the year on March 22 at magnitude 9.1. It starts the month at mag 9.7, brightens to 9.1 at opposition and fades back to 9.4 at month’s end. It spends the entire month in Virgo.

The Sky Tonight – Feb 28

I hope everyone was able to see the spectacular conjunction between Venus and the Moon. Even to this sometimes jaded astronomer, it was quite a sight to see. Right now it is the highlight of the year so far. But as nice as it looked, there will be an even better Venus-Moon pair-up in 2 months. You’ll need to get up in the early hours of the morning, but mark April 22 on your calendars. On that date, all of North America will see the Moon and Venus even closer to each other. And for central and western North America, the Moon will pass in front of (or occult) Venus. As a teaser, here what the view will be from Tucson at 5:00 am on April 22. Note, Mars will also be nearby with Jupiter visible many degrees away.

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The Venus-Moon (and Mars) conjunction that will take place on 2009 April 22. Image shows the scene over Tucson at 5:00 am that morning. Image from the Stellarium program (www.stellarium.org).

Tonight, the Moon has moved quite a bit away from Venus. It will not be quite the striking site it was last night but should still be impressive. A chart showing the relative position of Venus, the Moon, Comet Lulin, Saturn and the brighter stars can be seen below.

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Night sky on the evening of Feb 28 at 8:15 pm. Image made with the Stellarium software program (www.stellarium.org).

Comet Lulin continues to move rapidly to the west. Remember it was only a few days ago when the comet was right next to Saturn. Last night it was practically on top of Regulus, the brightest star in Leo. If you haven’t seen the comet, don’t wait. The comet is still at its brightest but will start to fade rapidly. That and the bright Moon for the next 2 weeks will make Lulin a tough site to see without a good sized pair of binoculars or telescope. Right now Lulin is a difficult naked eye object from a very dark site and an easy binocular object from just about anywhere.

Check Out the Moon and Venus Tonight (… and Comet Lulin) – Feb 27

Based on the number of comments I’ve been receiving, many people have been enjoying (or at least startled) by the grand display Venus has been putting on for the past few months. Tonight may be the best display yet as a very thin crescent Moon will join Venus.

This evening the Moon and Venus will be within 1.2 degrees of each other (for comparison the Moon is about 0.5 degrees across).

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Moon and Venus in conjunction on the evening of Feb 27. Image created with Stellarium (www.stellarium.org).

While you are observing the two, there are a few fun things to watch out for. One, even though the Moon is a thin crescent, can you see a faint glow from the rest of the Moon? Your eyes aren’t deceiving you, what you are actually seeing is called Earthshine. If you were standing on the nightside of the Moon right now you would be seeing a Full Earth. Just like the Full Moon on Earth, the Full Earth is very bright. In fact, it is much brighter than the Full Moon since the Earth is bigger and more reflective. So just like on Earth where the landscape is illuminated by the Full Moon, we are seeing the same phenomenon on the Moon.

Second thing to look for, if you have a pair of binoculars or a telescope (any size will do) check out the shape of Venus. Venus is also a thin crescent and is shaped  very similar to the Moon. Below is a picture of Venus that I took through my 12″ telescope on the evening of Feb25. Venus will still look pretty much the same tonight.

The image below was taken by myself with a 12″ reflector and DMK 41AF02 camera on the evening of Feb 25.

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Again if anybody gets some cool pictures of the pair and would like to share them with other blog readers, post a link in the comments section and I will include them in a future posting.

As for Comet Lulin, the comet still remains bright enough to be seen without optical aid if you live at a very dark site. For the rest of us, a nice pair of binolculars will suffice. Tonight the comet is easy to see as it is located just to the west (or right) of Regulus, the brightest star in Leo. It is best to wait until after 8:30 pm when the comet has risen high enough above the eastern horizon to be seen.

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Sky chart showing the position of Comet Lulin and Saturn for 9:30 pm on the night of Feb 27. Chart produced with the Stellarium software (www.stellarium.org).

Where is Comet Lulin Tonight?

Comet Lulin is still bright and easy to see. It is also rising earlier and earlier every night as it speeds into the evening sky. Tonight and tomorrow, the comet will be located near the bright star of Regulus in Leo.

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Sky chart showing the position of Comet Lulin and Saturn for 9:30 pm on the night of Feb 26. Chart produced with the Stellarium software (www.stellarium.org).

More on Comet Lulin can be found here at the “In The Sky This Month – February 2009” post.

A higher resolution finder chart for observers with binoculars or telescopes can be found at Heavens Above.

A great series of images can be found at Spaceweather.com.

Comet Lulin at its Best Tonight

Now is the best time to observe Comet Lulin. Two nights ago, Comet Lulin was easy to find as it passed close to Saturn, last night the comet came closest to Earth (0.411 AU or 38.2 million miles or 61.2 million km), and either tonight the comet will be at its brightest.

Don’t worry if you are not able to see the comet tonight. Just because the comet is at its brightest doesn’t mean it won’t be bright enough to see for the next few nights. And if you have a nice pair of binoculars or a telescope, the comet will be visible for the next 2 months.

Now why is the comet at its brightest tonight rather than last night when it was closer to Earth? First off, most observers will have a very hard time telling that the comet is brighter than last night. Chances are the comet will only be a few percent brighter, but there is a chance it could be brighter by 10-20%. Why? It all is related to how the dust particles in the atmosphere (or coma) and the tail of the comet scatter light.

Tonight, the comet will be located directly opposite in the sky from the Sun. In fact, the angle between the observer (on Earth), the comet and the Sun (Earth-comet-sun angle or phase angle) will only be 0.1 degrees. At such small phase angles, objects often appear much brighter than at larger phase angles. The reason is relatively simple, most of the time when you observe something, whether a comet, the Moon or blades of grass, you are looking at the object from the side a bit. So some fraction of the object is in shadow. When you are looking at the object with the Sun directly behind your line-of-sight, the shadows are no longer visible because they are behind the object. In effect, you are only seeing the sunlight side of the object.

A great explanation of the opposition effect (with pictures) can be found at the Atmospheric Optics site.This is also a great site for learning about a whole bunch of neat things that can be seen in the atmosphere.

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Sky chart showing the position of Comet Lulin and Saturn for 9:30 pm on the night of Feb 25. Chart produced with the Stellarium software (www.stellarium.org).

More on Comet Lulin can be found here at the “In The Sky This Month – February 2009” post.

A higher resolution finder chart for observers with binoculars or telescopes can be found at Heavens Above.

A great series of images can be found at Spaceweather.com.