Meteor Activity Outlook for May 12-18, 2012

The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.

May is a fairly slow month for meteor activity. The Eta Aquariids are very active the first two weeks of the month then fade as the month progresses. The only other showers active this month are the weak Nu Cygnids, the Eta Lyrids,  and the Antihelion radiant. These will add only 1-2 meteors per hour to the total count. Sporadic rates are low but steady as seen from the mid-northern hemisphere (45 N). Sporadic rates seen from the mid-southern hemisphere (45 S) are strong and remain so the entire month.

During this period the moon reaches its last quarter phase on Saturday the 12th. At this time the moon will be located ninety degrees west of the sun and will rise near 0100 local daylight time (LDT). As the week progresses the waning crescent moon will rise later in the morning, increasing the window of opportunity to view in totally dark conditions. The estimated total hourly rates for evening observers this week is near three for observers in the northern hemisphere and four for those south of the equator. For morning observers the estimated total hourly rates should be near nine as seen from mid-northern latitudes and fifteen from mid-southern latitudes. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Morning rates are reduced slightly due to moonlight during this period.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning May 12/13. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following showers are expected to be active this week:

The large Antihelion (ANT) radiant is currently located at 16:16 (244) -21. This position lies in northwestern Scorpius, six degrees northwest of the bright first magnitude orange star Antares (Alpha  Scorpii). Due to the large size of this radiant, Antihelion activity may also appear from western Ophiuchus, Libra, northern Lupus, as well as Scorpius. This radiant is best placed near 0200 LDT, when it lies on the meridian and is located highest in the sky. Rates at this time should be near one per hour as seen from the northern hemisphere and two as seen from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.

The last of the Eta Lyrids (ELY) are visible this weekend from a radiant located at 19:23 (292) +43. This position lies in extreme eastern Lyra, four degrees southwest of the third magnitude star Delta Cygni. This shower is active from May 6 through the 14th and peaked on May 11. Rates at maximum activity are near two per hour as seen from the northern hemisphere. Unfortunately the Eta Lyrid radiant does not rise very high in the northern sky as seen from the southern hemisphere so rates seen from below the equator are minimal. Activity from this shower is best seen during the last hour before dawn when the radiant is situated highest in a dark sky. With an entry velocity of 43 km/sec., the average Eta Lyrid meteor would be of medium speed.

The Eta Aquariids (ETA) are particles from Halleys Comet, produced in Earth-crossing orbits many centuries ago. We pass closest to these orbits from May 5 through the 9th. During this period the Eta Aquariids are at their best, capable of producing ZHRs of sixty. The actual visible rates are most often less than half this figure due to the low altitude of the radiant at dawn. Observed hourly rates at maximum normally vary from zero at 60 degrees north latitude to 30 near the equator and back down to near zero again in Antarctica, where the radiant elevation is again very low. Hourly rates this weekend will most likely be less than five per hour. Rates will slowly decrease as the week progresses as we move further from the May 7 maximum. The radiant is currently located at 22:52 (343) +01. This area of the sky is located on the Aquarius/Pisces border, three degrees east of the fourth magnitude star Eta Aquarii. The best time to view this activity is during the hour before the start of morning twilight, when the radiant lies highest in a dark sky. With the moon now in the morning eastern sky, it would be best to face either due north or due south, just enough to keep the moon out of your field of view. With an entry velocity of 67 kilometers per second, a majority of these meteors will appear to move swiftly with a high percentage of the bright meteors leaving persistent trains. Surprisingly, this shower produces very few fireballs.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately four sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near two per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near eight per hour as seen from rural observing sites and three per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are reduced due to moonlight.

The table below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

Antihelion (ANT) – 16:16 (244) -21   Velocity 30km/sec
Northern Hemisphere – 1 per hr Southern Hemisphere – 2 per hour

Eta Lyrids (ELY) – 19:23 (292) +43   Velocity 43km/sec
Northern Hemisphere – 1 per hr Southern Hemisphere – <1 per hour

Eta Aquariids (ETA) – 22:52 (343) +01   Velocity 67km/sec
Northern Hemisphere – 3 per hr Southern Hemisphere – 5 per hour

Clear Skies!
Robert Lunsford
American Meteor Society

 

Apr 26/27 to May 15/16 Meteors

April/May/June are usually clear months in Tucson and this year is setting up to be no different. Though bouts of cirrus are common, every night but one has been clear enough to allow the detection of a few meteors.

The past few weeks have seen a couple of showers come and go. Two minor showers, the Nu Cygnids and Northern May Ophiuchids, produced only 2 meteors apiece. These showers are recent discoveries and little is known about each. The Eta Lyrids produced 1-2 meteors per night at its best. This shower is produced by the long-period Comet IRAS-Araki-Alcock which passed closer to Earth than any other observed comet over the past 200 years (5 million km in May of 1983).

The highlight of May was the Eta Aquariids. Similar to the Orionids of October, the Eta Aquariids are produced by Comet Halley. This year’s display was hampered by a bright early morning Moon but still produced healthy numbers during the last hour or 2 of each early May night.

Obs  Date(UT)      Time    TOT SPO ANT PPU NCY ETA ELY NOP
TUS  2010-05-16   08h08m    10  8   1   -   -   1   -   -
TUS  2010-05-15   01h39m    3   3   0   -   -   0   -   -
TUS  2010-05-14   05h31m    8   5   1   -   -   1   1   -
TUS  2010-05-13   05h32m    12  8   1   -   -   1   1   0
TUS  2010-05-12   08h29m    15  8   1   -   -   4   2   0
TUS  2010-05-11   08h30m    22  13  3   -   -   4   2   0
TUS  2010-05-10   08h32m    9   3   1   -   -   2   2   1
TUS  2010-05-09   08h14m    12  6   1   -   -   5   0   0
TUS  2010-05-08   04h06m    13  8   1   -   -   3   0   1
TUS  2010-05-07   08h37m    18  10  0   -   -   8   0   0
TUS  2010-05-06   04h49m    15  9   0   -   -   6   0   -
TUS  2010-05-05   08h41m    11  4   1   -   0   6   -   -
TUS  2010-05-04   08h43m    7   1   0   -   1   5   -   -
TUS  2010-05-03   07h27m    14  10  0   -   0   4   -   -
TUS  2010-05-02   07h41m    5   2   2   -   0   1   -   -
TUS  2010-05-01   08h49m    12  9   2   -   0   1   -   -
TUS  2010-04-30   00h45m    3   2   0   -   0   1   -   - 
TUS  2010-04-29   08h52m    8   4   0   -   1   3   -   -
TUS  2010-04-28   00h00m    Bad Weather
TUS  2010-04-27   00h48m    2   2   0   0   0   -   -   -

TUS - Camera in Tucson operated by Carl Hergenrother
SDG - Camera in San Diego operated by Bob Lunsford
TotTime - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PPU - Pi Puppids
NCY - Nu Cygnids
ETA - Eta Aquariids
ELY - Eta Lyrids
NOP - Northern May Ophiuchids

Meteor Activity Outlook for May 8-14, 2010

The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.

May is a fairly slow month for meteor activity. The Eta Aquariids are very active the first two weeks of the month then fade as the month progresses. The only other showers active this month are the weak Nu Cygnids, the Eta Lyrids, and the Antihelion radiant. These will add only 1-2 meteors per hour to the total count. Sporadic rates are low but steady as seen from the mid-northern hemisphere (45 N). Sporadic rates seen from the mid-southern hemisphere (45 S) continue to rise this month toward a maximum in July.

During this period the moon reaches its new phase on Friday May 14th . At this time the moon lies near the sun and cannot be seen at night. This weekend the waning crescent moon will rise during the early morning hours but will not interfere with meteor observing as long as the observer keeps it out of the field of their field of view. The estimated total hourly rates for evening observers this week is ~2 for those in the northern hemisphere and ~3 for those south of the equator. For morning observers the estimated total hourly rates should be ~12 from the northern hemisphere and ~20 as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning May 8/9. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following showers are expected to be active this week:

Antihelions (ANT)

The wide Antihelion (ANT) radiant is now centered at 16h:04m (241) -21. This area of the sky lies in northwestern Scorpius just one degree to the southwest of the third magnitude star Acrab (Beta Scorpii). This radiant is best placed near 0200 local daylight time (LDT) when it lies on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from eastern Libra, northern Lupus, southern Ophiuchus, or western Scorpius could be a candidate for this shower. Rates at this time should be near one per hour as seen from the northern hemisphere and two per hour as seen from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

Eta Lyrids (ELY)

The Eta Lyrids (ELY) are visible this week from a radiant located at 19h:24m (291) +43. This position lies in extreme eastern Lyra, four degrees southwest of the third magnitude star Delta Cygni. This shower is active from May 6 through the 13th, peaking on May 10. Rates at maximum activity are near two per hour as seen from the northern hemisphere. Unfortunately the Eta Lyrid radiant does not rise very high in the northern sky as seen from the southern hemisphere so rates seen from below the equator are minimal. Activity from this shower is best seen during the last hour before dawn when the radiant is situated highest in a dark sky. With an entry velocity of 43 km/sec., the average Eta Lyrid meteor would be of medium speed.

Eta Aquariids (ETA)

The Eta Aquariids (ETA) are particles from Halley’s Comet, produced in Earth-crossing orbits many centuries ago. We pass closest to these orbits from May 5 through the 9th. During this period the Eta Aquariids are at their best, capable of producing ZHR’s of sixty. The actual visible rates are most often less than half this figure due to the low altitude of the radiant at dawn. Observed hourly rates at maximum normally vary from zero at 60 degrees north latitude to 25 near the equator and back down to near zero again in Antarctica, where the radiant elevation is very low. Hourly rates this weekend are anywhere from zero to ten per hour depending on your latitude and observing conditions. Rates will slowly decrease as we move further away from the May 7 maximum. The radiant is currently located at 22h:40m (340) +00. This area of the sky is located in northeastern Aquarius, just one degree east of the fourth magnitude star Eta Aquarii. The best time to view this activity is just before the start of morning twilight, when the radiant lies highest in a dark sky. No matter your location these meteors will appear from the eastern sky and shoot in all directions. If the radiant has sufficient altitude Eta Aquariid meteors can also be seen shooting down toward the eastern horizon. With an entry velocity of 67 kilometers per second, a majority of these meteors will appear to move swiftly with a high percentage of the bright meteors leaving persistent trains. Surprisingly, this shower produces very few fireballs.

The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

Shower Name                RA     DEC   Vel     Rates
                                        km/s   NH    SH
ANT Antihelions          16h 04m  -21    30     1     2
ELY Eta Lyrids           19h 24m  +43    42     2    <1
ETA Eta Aquariids        22h 40m  +00    67     5     6

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a
        dark site
NH - Northern Hemisphere
SH - Southern Hemisphere

May 9/10/11 Meteors

This is more like it. After 2+ months of very low meteor rates, May brings rates to be excited about. This is due to 3 factors. 1) The weather is great. May is in the middle of Tucson’s dry season. Though high cirrus is possible and you can’t rule out the rare rain event, it is usually hot and bone dry. Yesterday’s high was 101F and the humidity was a paltry 4%. 2) We have 2 active showers producing a few meteors per night, the Eta Aquarids and Eta Lyrids. 3) The number of background Sporadics are slowly increasing from their annual low in the Spring.

Obs  Date (UT)   TotTime TOT SPO ANT ETA ELY
TUS  2009-05-11  07h 42m  9   4   2   1   2
TUS  2009-05-10  08h 29m  15  8   2   4   1

TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
ANT – Antihelions
ETA - Eta Aquarids
ELY - Eta Lyrids

May 5/6/7/8/9 Meteors

The Eta Aquarids were predicted to peak during the evening of May 5. For observers in North America, this means the mornings of May 5 and 6 should have produced the most meteors. Interestingly, the number of Eta Aquarids being detected nightly is not much lower than the nights around the peak. This suggests the ETAs have a broad peak with maximum activity being seen over many nights. This is in contrast to showers like the Quadrantids or the Lyrids of 2 weeks ago that have narrow peaks that last for only a day. The ETA are more similar to the Orionids of October which is not surprising since both showers are produced by Comet Halley.

Though much less active than the Eta Aquarids, the Eta Lyrids are also producing a meteor or so every night or two. The minor shower is derived from Comet IRAS-Araki-Alcock, a comet which passed extremely close to the Earth in May of 1983.

Bob made a trek into the Southern California mountains to find darker skies. His results from the nights bracketing the ETA peak are included in the table below. From his notes: “Skies have been mostly cloudy at night in the San Diego area since the Lyrid maximum. In fact I had to drive to the local mountains to record any activity from the Eta Aquariids.”

Obs  Date (UT)   TotTime TOT SPO ANT ETA ELY
TUS  2009-05-09  07h 50m  15  6   0   8   1
TUS  2009-05-08  08h 29m  14  6   1   7   0
TUS  2009-05-07  08h 36m  9   4   0   3   2
SDG  2009-05-07  02h 00m  38  18  2   17  1
TUS  2009-05-06  06h 44m  9   1   0   8   0
SDG  2009-05-06  02h 00m  44  22  3   19  0

TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
ANT – Antihelions
ETA - Eta Aquarids
ELY - Eta Lyrids

In The Sky This Month – May 2009

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of May 2009.

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 - Last month saw Mercury’s best evening apparition of 2009 (at least for Northern Hemisphere observers). Mercury is now descending back into the glow of the Sun. For the first week or so of the month it is still visible low in the west during evening twilight. Unlike last month, it is much fainter now (+0.9 magnitude on the 1st, +3.7 on the 11th).

Saturn – Saturn is the easiest planet to observe in May. By the end of twilight, Saturn is just south of zenith (straight up) under the eastern part of the constellation of Leo.

This year Saturn is dimmer than usual. At magnitude +0.8 to +0.9, there are at least a dozen stars that are brighter than it. The reason is 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 on April 23.

saturn_20090423_0543_crop1

Image of Saturn by C. Hergenrother. April 23 w/ 12" with DMK41AF02 camera.

The Moon will pass a relatively distant 5.5 degrees to the south of Saturn on the evening of May 3.

Venus - Venus continues to slowly climb higher every night. It is currently a morning object and is best seen an hour before sunrise low in the eastern sky. For Southern Hemisphere observers, it will reach its highest point during the 2nd half of the month. For Northern observers, Venus will continue to climb higher until early August.

For binocular and telescope users, Venus will start the month as a large fat crescent, 39″ across and only 25% illuminated. By the end of the month, it will have shrunk to 25″ across but will also be nearly half illuminated at 46%.

Jupiter and Neptune - Jupiter rises a few hours before sunrise. By the end of the month, the king of the planets peaks above the horizon a little after midnight. Other than Venus, it is the brightest “star” in the morning sky at magnitude -2.2 to -2.4. Due to Jupiter’s location in the southern constellation of Capricornus , it never gets very high this year.

For those with a telescope or binoculars and a dark sky, Jupiter will pass close to the planet Neptune on the morning of May 27. At their closest, the 5th and 8th planet will only be 0.39 degrees apart. Jupiter will be a bright magnitude -2.4 while Neptune will be a faint +7.9. That makes Jupiter nearly ~12,000 times brighter than Neptune. Even Jupiter’s 4 large Galilean moons are about a dozen times brighter than Neptune even though they are much smaller. The big reason for the faintness of Neptune is its distance from both the Earth and Sun. It is roughly 6 times further away from us and the Sun as Jupiter. It’s distance also explains its apparent small size of 2.3″. A telescope will be required to see Neptune as anything other than a faint star.

Though Neptune wasn’t discovered until 1846, it was actually observed by Galileo on two occasions in 1612 and 1613. Similar to this month’s circumstances, Jupiter was passing very close to Neptune. Galileo observed and recorded Neptune as a star in the vicinity of Jupiter. There is also evidence that he noticed that Neptune had moved but didn’t follow up on it. So when you observe these 2 planets imagine what Galileo must have been thinking nearly 400 years ago.

Uranus – Uranus is located in western Pisces. It is bright enough to be seen in small binoculars at magnitude +5.9 but will still require a telescope in order to see it as anything other than a star (it’s disk is only 3.4″ across).

Both planets are early morning objects low in the southeastern sky.

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 passed a distant 4 degrees to the north of Mars on April 24. Mars and Venus will continue to move apart until around mid-month when they will be 6.5 degrees apart. After that their distance from each other will shrink as they approach a 2 degree conjunction on June 21.

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

Eta Aquarids (ETA)

The Eta Aquarids are a major shower, especially for southern hemisphere observers, when they peak on May 5. For northern observers, the shower will only be observable for an hour or two before dawn. Since the radiant doesn’t get very high for NH observers, rates can be low. The radiant is located near the “jar” of Aquarius.

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. By luck, the nearly Full Moon will have just set making the last hour of the night dark.

The shower spans from April 19 to May 28 with a peak around May 5 with a maximum ZHR of ~60.

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.

Minor Meteor Showers

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

Eta Lyrids (ELY)

This shower is associated with Comet C/1983 H1 (IRAS-Araki-Alcock). The comet is a long-period comet which passed within 0.03 AU of the Earth on 1983 May 11. Discovered by astronomers using the Infrared Astronomical Satellite (IRAS) and two amateur astronomers, Genichi Araki (Yuzawa, Niigata, Japan) and George Alcock (Peterborough, England, UK), the comet brightened to 1st magnitude for a few days around closest approach.

Though the comet is now long gone and will not return for quite some time, particles released during past perihelia can be observed every year in early May. The Eta Lyrids are a minor shower that have never produce more than ~3 meteors per hour. Peak time in on May 8 though some meteors can be seen from May 3-12. Meteors will appear to radiate from a point in the middle of a triangle made up of the bright stars Vega and Deneb and the “head” of the constellation Draco. The Moon, Full on May 7, will spoil the Eta Lyrids for this year.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V < 8.0)

None

Small Telescope Comets (V < 10.0)

Comet C/2009 F6 (Yi-SWAN)

Comet C/2009 F6 (Yi-SWAN) is a long-period comet which will pass within 1.27 AU of the Sun on May 7. 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 northeast of the Sun. For southern hemisphere observers, you are out of luck. For northern observers, the comet can be observed in the evening sky.

The comet starts the month in Perseus. As it travels to the southeast, it will enter Auriga by the last week of the month. The comet will never get far from the horizon so a clear dark northwestern horizon is a must to see this comet. By mid-month the comet will be too close to the Sun for easy observation.

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. Unfortunately, in May the comet will not be visible in the morning.

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.

A finder chart for Comet Yi-SWAN can be found at Comet Chasing and Aktuelle Kometen (in German).

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/2008 Q3 (Garradd)

Sometimes comets surprise us. From time to time what appears to be a faint run-of-the-mill comet will undergo an outburst and brighten substantially. This is the case with Comet Garradd. Gordon Garradd of the Siding Spring Survey (Australia) used the 0.5-m Uppsala schmidt telescope to discover this comet back on 2008 August 27.

The comet was a faint 19th magnitude at discovery. With perihelion expected on 2009 June 23 at 1.80 AU from the Sun, it was expected to brighten but only to about 12th-14th magnitude. Two weeks ago the comet was sitting at 15th magnitude. Bright enough for CCD imaging but too faint for nearly all visual observers. On April 20th Micheal Jager imaged the comet and found it too be much brighter. Over the next few days, visual observers were able to confirm the outburst and estimated the comet to be as bright as magnitude 8.9.

Whether the comet will continue in its excited state and brighten further as it approaches perihelion is not known. It’s possible that the outburst will be short-lived and the comet may revert back to its original activity level.

Right now this comet is only observable from the Southern Hemisphere as it rockets through the constellations of Indus, Pavo, Apus, Triangulum Australe, and Circinus. For us up north, the comet will become visible in June as an evening object.

I hope to have a link to a finder chart for this comet up soon.

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.

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 and Aktuelle Kometen (in German).

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/2009 G1 (STEREO)

Jiangao Ruan of China found this comet on images taken by the SECCHI HI-1B instrument onboard one of the STEREO spacecraft. The comet was first visible on images taken on April 3 UT. Similar to SOHO (a spacecraft that was used to co-discover Comet C/2009 F6 (Yi-Swan)), the two STEREO spacecraft study the Sun and its immediate environment.

With perihelion on April 16 at 1.13 AU from the Sun, the comet is now moving away from the Sun. Luckily it is still moving closer to the Earth, though it will get no closer than 1.06 AU from Earth. With a current estimated magnitude of ~9.0, the comet may brighten a bit as it gets closer.

The comet starts the month in southern Aquarius and will pass through Sculptor before finishing the month in the far southern constellation of Phoenix. It was never an easy object for northern observers and is now only observable from southern latitudes.

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

A nice collection of images can be found at Seiichi Yoshida’s Comet Homepage.

Comet C/2009 E1 (Itagaki)

This comet was found by amateur astronomer Koichi Itagaki of Yamagata, Japan on March 14. 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 morning sky moving through Andromeda and to just north of the “square” of Pegasus. Due to its proximity to the Sun over the past few weeks, it hasn’t been observed since early April. At the time, it was magnitude 7.5-8.0. If it is still in the magnitude ~8.0 to 8.5 range then the  comet will bright enough to be seen in a reasonably sized backyard telescope.

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/2008 T2 (Cardinal)

Rob Cardinal, an astronomer at the University of Calgary in Canada, discovered this comet last October. The comet was discovered as part of a survey at  the Rothney Astrophysical Observatory for new Near-Earth asteroids at high declinations. In fact the comet was found within 10 degrees of the North celestial pole. At the time of discovery, the comet was ~14th magnitude.

At perihelion on June 13th of this year, the comet will pass within 1.20 AU of the Sun. The comet is currently ~9.0 to 9.5 magnitude as it moves south across Gemini into Canis Minor in the evening sky. The comet should continue to brighten by another magnitude this month. Similar to most comets, access to a clear western horizon is necessary to see it.

A finder chart for Comet Cardinal can be found at Comet Chasing and Aktuelle Kometen (in German).

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. This month Ceres fades from from magnitude 8.0 to 8.4 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.

(8) Flora and (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 fade from magnitude 9.0 to 9.7 as it moves through central Virgo.

Though it is a bit fainter than the asteroids I usually present, those up for a challenge can spot the asteroid (8) Flora a few degrees away from Irene.

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 9.9. By the end of the month, it has faded to 10.5. Flora and Irene provide us with a 2-for since both objects are located within 5 degrees of each other.

Since I have not been able to find a nice star chart showing the position of Irene and Flora, here is one I made with the C2A program. The bright star that Flora passes close to towards the end of the month (right side of the chart, white circle) is zeta Virginis.

flora_irene_may

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