May 25/26 to 29/30 Meteors

Recent video meteor rates have been very disappointing the last few nights. I’m not sure why they are so low. I’m sure the nearly Full Moon has something to do with it. Plus any dust in the air can’t be helping. Still whenever rates drop this low I start to wonder if there is a problem with my camera setup. Maybe it’s time to take a closer look and see if anything else is affecting the system.

Obs  Date(UT)      Time    TOT SPO ANT
TUS  2010-05-30   05h45m    5   5   0
TUS  2010-05-29   08h02m    5   3   2
TUS  2010-05-28   08h02m    5   5   0
TUS  2010-05-27   07h56m    6   6   0
TUS  2010-05-26   07h48m    5   2   3

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 - Antihelion

2010 KQ is probably not an asteroid

A few days back I posted about a very small asteroid orbiting on a very Earth-like orbit. At the time the nature of the object had not been determined. It was surmised that it could be a small natural asteroid or a returning piece of man-made space hardware.

NASA’s NEO Project Office at JPL is now reporting that 2010 KQ is probably not an asteroid. That determination is based on ground-based photometry and spectroscopy by 2 telescopes in Hawaii. Richard Miles used the British Faulkes North telescope to obtain visible wavelength colors and Bobby Bus used the NASA IRTF telescope to obtain near-infrared spectra. Both observers found the object to display colors that are not common among asteroids. A similar occurrence happened back in 2002 when a newly found “asteroid” was identified as the returning S-IVB upper stage from Apollo 12. At that time Rob Whiteley and I were the first to get visible color photometry on the object. Our data showed the object to much redder than any natural solar system object. Additional IRTF data identified spectral features corresponding to organic binders in paint.

“2010 KQ” is probably a rocket upper stage that was used to launch a satellite to very high Earth orbit, the Moon or interplanetary space. Though upper stages are metallic and may or may not be painted, exposure to the solar wind will quickly redden them (a process called space weathering). The orbit of “2010 KQ” suggests the last close approach with Earth was in April 1975. There were no interplanetary launches that month. It is still possible something launched into a high Earth orbit a few years before could have stayed in a loosely bound Earth orbit until it finally leaked into orbit around the Sun in April of ’75. Two possible candidates are the German-American solar probe Helios-1 (launched on Dec 10, 1974) and the Russian lunar sample return mission Luna 23 (launched on Oct 28, 1974). As observations are made over the next few months, we will have a better understanding of when this object left the Earth-Moon system. The best source for updates on the orbit and nature of KQ is Bill Gray’s pseudo-MPEC site.

Launch cover for the Helios-1 s/c produced by Space Voyage Covers.

May 22/23/24/25 Meteors

Video meteor rates have varied by a factor of 3 over the past 3 nights. Each night was clear though the low rates on the night of May 22/23 may have been due to lots of wind-blown dust in the air. The night of May 23/24 was a late start. I was so caught up in the LOST finale that I almost forgot to turn on my camera.

With no confirmed showers active this week, most of the meteors have been sporadics with the occasional antihelion. Rates should be suppressed over the next week as the bright Moon enters the morning sky.

I changed the theme (format and background) of the blog yet again. The current theme is very similar to the previous one. Its advantages are the easy-to-use category tags at the top of the blog and increased readability.

Obs  Date(UT)      Time    TOT SPO ANT
TUS  2010-05-25   08h01m    14  13  1
TUS  2010-05-24   04h06m    9   8   1
TUS  2010-05-23   07h24m    5   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 - Antihelion

Two Close Asteroid Fly-bys

A day or so ago I posted about a close approach by 2010 KQ, a small asteroid only about 2-6 meters across. KQ is not the only small asteroid to buzz the Earth recently. Two more asteroids, 2010 KO10 and 2010 KV39, are in the vicinity of Earth and both get much closer than 2010 KQ. Both asteroids will safely miss the Earth and don’t pose a hazard.

2010 KO10 was first seen by Rik Hill of the Catalina Sky Survey on May 20.32 UT. The 6 to 25 meter in diameter space rock passed within 112,000 miles (0.0012 AU or two-thirds of the way to the Moon) on  May 23.2 UT. At its brightest it got up to 14th magnitude, possibly putting it in visual range of very large amateur telescopes.

Orbital Parameters for 2010 KO10:
Perihelion distance = 0.920 AU
Aphelion distance = 1.032 AU
Semi-major axis = 2.984 AU
Inclination = 8.14°
Period = 2.73 years

Orbit of 2010 KO10 and the inner planets. Created with C2A. Credit: Carl Hergenrother.

.

Last night (at around May 24.37 UT) the Catalina Sky Survey (this time with Alex Gibbs as observer) picked up 2010 KV39. Tomorrow night at May 26.9 UT, 2010 KV39 will pass within 160,000 miles of Earth. Though similar in size to 2010 KO10, KV39 will only get as bright as 16th magnitude.

Orbital Parameters for 2010 KV39:
Perihelion distance = 0.714 AU
Aphelion distance = 0.958 AU
Semi-major axis = 1.203 AU
Inclination = 13.90°
Period = 0.94 years

Orbit of 2010 KV89 and the inner planets. Created with C2A. Credit: Carl Hergenrother.

Meteor Activity Outlook for May 22-28, 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 full phase on Thursday May 27th . At this time the moon lies opposite of the the sun and is in the sky the entire night. Conditions are more favorable this weekend as the waxing gibbous moon will set during the early morning hours allowing a couple hours of darkness between moonset and the start of morning twilight. The estimated total hourly rates for evening observers this week is ~1 for those in the northern hemisphere and ~2 for those south of the equator. For morning observers the estimated total hourly rates should be ~7 from the northern hemisphere and ~17 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 22/23. 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:56m (254) -23. This area of the sky lies in southern Ophiuchus some seven degrees northeast of the first magnitude star Antares (Alpha 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, southern Serpens Cauda, western Sagittarius, or 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.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately six sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near one per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near fifteen per hour as seen from rural observing sites and two per hour during the evening hours.

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 56m  -23    30     1     2
--------------------------------------------------------

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

2010 KQ – a very small, very close asteroid

Small asteroids buzz past the Earth every day. The great majority of them pass by sight unseen. One little asteroid, now named 2010 KQ, was picked up by the Catalina Sky Survey on the night of May 16. The fact that this object is small and passing close to Earth is not unusual. Rather it’s orbit is the interesting thing about  this object.  2010 KQ has an orbit that is very Earth-like as the diagram and table below shows.

Orbit of 2010 KQ and the inner planets. Created with C2A. Credit: Carl Hergenrother.

Orbital Parameters:
Perihelion distance = 1.016 AU
Aphelion distance = 1.032 AU
Semi-major axis = 1.024 AU
Inclination = 0.07°
Period = 1.04 years

Currently the official orbit sources give 2010 KQ an absolute magnitude (H) of 28.3 which corresponds to a diameter of 3-8 meters. This H value makes a few assumptions. My independent analysis of it brightness suggests it might be smaller and fainter with an H value of 29.9. This results in smaller diameters of 2-6 meters. Either way this is a small asteroid and only a handful of smaller ones have been detected. I will be able to better define these values as more observations are made.

The very Earth-like orbit creates very slow, long Earth fly-bys. Close approach happened yesterday (May 21) at a distance of 0.0033 AU (~490,000 km or 290,000 miles). That’s just a little further than the Moon.

Small objects on similar orbits have been found in the past. Only one of these objects turned out to be a natural asteroid. All of the others were man-made space hardware. Just like on Earth where it is hard to travel anywhere without running across man-made structures or garbage, space is also littered with working and non-working satellites, rocket bodies, and assorted nuts and bolts.

Bill Gray does an excellent job of monitoring these sorts of objects and determining whether they are natural or man-made. He studies the motion of the objects along their orbits. Man-made objects are light and have a large surface area to mass ratio. This allows the solar wind and other non-gravitational forces to change the motion of the objects. Within a week or so, he should have enough data to declare the object an asteroid or just space junk. He has set up a site where you can follow the current orbit of KQ and his current thoughts on its nature.

The last time KQ was in the vicinity of Earth was back in August 1990. Prior to that it passed Earth in 1975. Perhaps it is a piece of an interplanetary or high-Earth orbit spacecraft mission launched during those times (though the 1990 date already looks unlikely).

May 16/17 – 21/22 Meteors

The past week saw the end of activity from the Halley-produced Eta Aquariids. Though there are few active showers (minor or major) for the next few weeks, background sporadic activity continues to increase as we approach the summer.

Obs  Date(UT)      Time    TOT SPO ANT ETA
TUS  2010-05-22   07h59m    6   5   1   -
TUS  2010-05-21   07h34m    14  12  1   1
TUS  2010-05-20   03h01m    10  9   0   1
TUS  2010-05-19   08h07m    10  9   1   0
TUS  2010-05-18   03h28m    11  10  0   1
TUS  2010-05-17   07h29m    7   6   1   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 Aquariid

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

In The Sky This Month – May 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of May 2010. Venus continues to ascend higher in the evening sky and is the brightest star during early evening hours. The major meteor shower, Eta Aquariids, will be washed out by a bright Last Quarter moon.

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

Planets

Venus – Venus is the brilliant star low in the west during the early evening hours. It sets about 2 and half hours after the Sun. Venus will only get a little higher next month. From now till July/August it will ride as high as it’ll get for this apparition for northern observers. In fact, this is not a very good evening apparition for Venus. On the other hand, it is a great apparition for observers south of the Equator. For you, Venus will continue to climb till late August.

May 16 - Moon passes within 0.6° from Venus

Mars – This month the Earth and Mars continue to move further apart. As a result, Mars will continue to fade from magnitude +0.7 to +1.1. Still it will be a bright red beacon nearly overhead right after sundown. It’s brightness is comparable to that of the other bright stars. Note that unlike the stars which twinkle, Mars shines with an unwavering red glow.

May 20 - Moon passes within 5° of Mars

Saturn – Saturn was at opposition in Virgo on March 21. This month Saturn is visible in the east-southeast during the early evening hours. It will slowly fade from magnitude +0.8 to +1.0 throughout the month. Telescope users should note that Saturn’s rings are still within a few degrees of edge-on.

May 22 - Moon passes within 8° of Saturn

JupiterJupiter once again returns to sight as a brilliant star low in the east-southeast before dawn. The magnitude -2.2 planet will get brighter and better place for observing over the next few months.

May 9 - Moon passes within 6° of Jupiter

Mercury -Mercury will rise out of the dawn sky toward the end of the month. This morning apparition will not be good for northern observers.

May 12 - Moon passes within 8° of Mercury

Meteors

May starts to see an increase in meteor activity after a few months of low activity. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

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 May, 10-12 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Eta Aquariids (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.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: 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 = 6.0 – 8.0)

Comet C/2009 R1 (McNaught)

There are 2 comets bright enough to be seen in small telescopes this month. Both were discovered by Rob McNaught of Australia during the Siding Spring Survey. As a result, both comets go by the moniker of Comet McNaught though they do have different designations [Comet C/2009 K5 (McNaught) and Comet C/2009 R1 (McNaught)].

The comet that should end the month as the brightest is Comet C/2009 R1 (McNaught). This comet was found on Sept. 9, 2009 with the 0.5-m Uppsala Schmidt telescope from Australia. At the time, the comet was a faint 17th magnitude.

Perihelion will be on July 2nd of this year at a relatively small distance of 0.41 AU from the Sun. This month it will be 1.44 AU from the Sun and 1.96 AU from Earth on May 1st, 1.19 AU from the Sun and 1.61 AU from Earth on the 15th, and 0.90 AU from the Sun and 1.28 AU from Earth on the 31st. Currently the comet is around magnitude 10.0 and should brighten to ~7.0 by the end of the month. 10th magnitude requires a small telescope but under dark skies while 7th magnitude should be easy for small telescopes under most sky conditions and binoculars under a dark sky. It is a morning object as it moves from Pisces, through Pegasus and into Andromeda.

This comet may even brighten to naked eye brightness (under very dark skies) in June. Of course with relatively small comets getting this close to the Sun, there is always a chance the comet will break up and disintegrate before it gets too bright (as C/2009 O2 did last month).

Orbits and position of Comet C/2009 R1 and the planets for May 15, 2010. Image created with C2A. Credit: Carl Hergenrother.

A finder chart for Comet McNaught 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 = 8.0 – 10.0)

Comet C/2009 K5 (McNaught)

The 2nd ‘Comet McNaught’  is Comet C/2009 K5 (McNaught). It was discovered on May 27, 2009 deep in the southern sky. Similar to C/2009 R1, this comet was also found with the Uppsala schmidt at around magnitude 17.

With perihelion on April 30 of this year at a distance of 1.42 AU from the Sun, C/2009 K5 is bright enough to be seen in small backyard telescopes from dark sites. During the month it should be as bright as it gets at around magnitude 8.2 to 9.0. The comet will move through Cepheus and Camelopardalis. As the month progresses, the comet will have traveled far enough north to be circumpolar and visible all night long (for observers at northern mid-latitudes and further north).  At mid-month it will be located 1.44 AU from the Sun and 1.51 AU from Earth.

Orbits and position of Comet C/2009 K5 and the planets for May 15, 2010. Image created with C2A. Credit: Carl Hergenrother.

A finder chart for Comet McNaught 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 < 9.0)

(4) Vesta

Vesta is the brightest asteroid in the Main Belt. This is due to its high albedo (or reflectivity) which causes it to reflect ~42% of the light that strikes it. Vesta is also 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 has dimensions of 347x336x275 miles or 578×560×458 km.

The maps below were created from images taken with the Hubble Space Telescope. The geography is dominated by a large impact crater located near the south pole (the blue ‘donut’ in the elevation map). Perhaps this crater is the result of the impact that blasted off the smaller V-type asteroids. We’ll know more next year when NASA’s Dawn spacecraft enters orbit around Vesta for a full year. Currently the encounter is scheduled for July 2011 to July 2012.

Images and models of the shape of asteroid (4) Vesta. In the upper left is a real HST image, to the upper right is a model of Vesta’s shape, and on the bottom is an elevation map . Credit: NASA/STScI.

Vesta starts the month at magnitude 7.3 and steadily fades to mag 7.7. A small pair of binoculars will allow you to see Vesta among the stars of Leo.

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.

(2) Pallas

Pallas is a dark 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 similar in size to Vesta with dimensions of 350x334x301 miles or 582x556x501 km. The reason it is fainter than Vesta is its darker albedo of 16%. Though no spacecraft are scheduled to visit Pallas, Hubble was able to get some good images that clearly show its nearly spherical shape.

This month it fades from magnitude 8.7 to 9.0. Over the course of the month it travels north from the constellation of Serpens Caput into Corona Borealis.

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.

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