Meteor Activity Outlook for May 28-June 3, 2011

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.

June is another slow month for meteor activity. There are no major showers active in June and only the Antihelion source can be counted on for continuous activity. Even the Antihelion is located so far south this time of year that rates rarely exceed two per hour as seen from the northern hemisphere. Sporadic rates reach their nadir in June 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 Wednesday June 1st. At this time the moon will lie near the sun and will not be visible at night. This weekend the waning crescent moon will not cause any problems viewing meteor activity as it is very thin and rises late in the morning. The estimated total hourly rates for evening observers this week is near three as seen from the northern hemisphere and four as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near eight from the northern hemisphere and eighteen as seen from south of the equator. 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 (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning May 28/29. 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:

According to Peter Jenniskens, the Earth will pass only 0.0011 AU (100,000 miles) from the 1952 trail of comet 73P/Schwassmann-Wachmann 3 near  05:45 UT on June 2. This corresponds to 1:45am EDT, 12:45am CDT, 11:45pm MDT (on June 1st), and 10:45pm PDT (on June 1st). Unfortunately the comet was relatively inactive on this return and this trail is not expected to produce any activity this year. Still, I would urge observers to try and verify any activity near
the times listed above. This variable shower is known as the Tau Herculids (TAH) and last produced activity back in 1995, when parent comet broke up into several pieces. The radiant is expected to be near the position of 15:44  (236) +41. This area of the sky is located where the boundaries of Bootes, Corona Borealis, and Hercules meet. The nearest easily seen star is Mu Bootis, which lies four degrees southwest of the radiant in northern Bootes. This area of the sky lies high in the east once it becomes dark. It passes nearly overhead near 0100 local daylight time. Luckily, the moon is near new and will not interfere with observing at all. Please post your results either positive or negative to meteorobs as soon as possible. If no activity occurs as expected, then the next close approach will occur in 2017 from the 1941 trail. Looking even further ahead, in 2022, the Earth encounters many trails of SW3, including two of the very active 1995 trails, and an outburst of activity is expected.

The wide Antihelion (ANT) radiant is now centered at 17:24 (261) -23. This area of the sky lies in southeastern Ophiuchus, two degrees northeast of the third magnitude star Theta Ophiuchi. This radiant is best placed near 0200 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 southern Ophiuchus, western Sagittarius, Serpens Cauda, or Scorpius could be a candidate for this shower. Rates at this time should be near two per hour as seen from the northern hemisphere and three 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 two 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 three per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.

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
TAU Tau Herculids         15h 44m  +41    15    <1    <1
ANT Antihelions           17h 24m  -23    30     2     3

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

Meteor Activity Outlook for May 21-27, 2011

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 but beginning to decline.

During this period the moon reaches its last quarter phase on Tuesday May 24th. At this time the moon will lie ninety degrees west of the sun and will rise near 0100 local daylight time (LDT) for observers at mid-northern latitudes. This weekend the waning gibbous moon will seriously interfere with meteor observing as the fainter meteors will be obscured by the lunar glare. As the week progresses conditions will improve and the moon wanes and rises later in the morning. The estimated total hourly rates for evening observers this week is near three as seen from the northern hemisphere and four as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near four from the northern hemisphere and nine as seen from south of the equator. 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 due to moonlight.

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 21/22. 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 wide Antihelion (ANT) radiant is now centered at 16:56 (254) -22. This area of the sky lies in southwestern Ophiuchus, six degrees northeast of the first magnitude orange star Antares (Alpha Scorpii). This radiant is best placed near 0200 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 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 three 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 seven 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 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  -22    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

The Ups and Downs of T Pyx

Let me just say that I really like this star. On the evening of May 7th UT (6th in local time) I measured T Pyx at magnitude 6.8. This was just a tenth of a magnitude brighter than a convenient magnitude 6.9 star located nearby. The next night I was expecting to find T Pyx even brighter but was surprised to find it fainter than the nearby reference star. After a break of a few days I wasn’t sure what to expect but I was pleasantly surprised to find T Pyx has brightened yet again. My observations placed it as magnitude 6.5.

If all goes according to predictions based on its 1966 outburst, the nova should brighten by another few tenths of a magnitude during the next week or so. Then begins its long fade back to quiescence.

Visual and CCD magnitude measurements for T Pyx. Credit: AAVSO.

T Pyx Fading?

This evening I took another peak at T Pyx and was surprised to find it looking a bit fainter than it did last night. The lightcurve from the AAVSO suggests that T Pyx may have been slowly fading over the past 3 days or so. It will be interesting to see if this is a short-term dip before brightening to its predicted peak later this month, or if this is the beginning of a fade back to quiescence.

Visual and CCD V lightcurve for T Pyx from the AAVSO LightCurve Generator. Credit: AAVSO.

April 21 – 30 Meteors

The last 10 nights of April  saw the peak of one major shower (the Lyrids) and the beginning of activity for May’s only major (the Eta Aquariids).

Obs  Date(UT)      Time    TOT SPO ANT SLE PPU LYR NCY HVI ETA
SAL3 2011-04-31   08h 29m   8   5   1   -   -   -   0   -   2
ALLS 2011-04-30   08h 44m   6   4   0   -   -   -   0   -   2
SAL3 2011-04-29   08h 52m   10  9   0   -   -   -   0   -   0
ALLS 2011-04-29   09h 20m   4   4   0   -   -   -   0   -   0
SAL3 2011-04-28   02h 58m   9   7   2   -   0   -   0   -   0
ALLS 2011-04-28   08h 59m   7   4   2   -   0   -   0   -   1
SAL3 2011-04-27   08h 57m   10  8   2   -   0   -   0   -   -
ALLS 2011-04-27   09h 28m   3   2   1   -   0   -   0   -   -
VISH 2011-04-27   01h 00m   3   1   -   -   -   -   -   -   2 (LM=6.0)
SAL3 2011-04-26   08h 41m   11  6   3   -   0   -   0   2   -
ALLS 2011-04-26   08h 56m   8   7   1   -   0   -   0   0   -
SAL3 2011-04-25   09h 01m   4   3   1   0   0   0   0   0   -
ALLS 2011-04-25   09h 29m   3   3   0   0   0   0   0   0   -
SAL3 2011-04-24   04h 40m   13  7   0   0   0   5   1   0   -
ALLS 2011-04-24   09h 34m   12  6   1   0   0   5   0   0   -
SAL3 2011-04-23   09h 04m   17  8   0   1   0   8   0   0   -
ALLS 2011-04-23   09h 35m   8   4   0   0   0   3   1   0   -
HERM 2011-04-23   01h 29m   5   1   1   0   0   3   0   0   -
SAL3 2011-04-22   09h 07m   15  3   1   0   0   8   1   2   -
ALLS 2011-04-22   09h 37m   11  0   1   0   0   9   1   0   -
HERM 2011-04-22   06h 07m   14  4   4   1   0   5   0   0   -
VISH 2011-04-22   01h 00m   2   1   -   -   -   1   -   -   - (LM=5.0)
SAL3 2011-04-21   09h 09m   12  6   0   0   0   5   1   -   -
ALLS 2011-04-21   09h 39m   8   5   0   0   0   2   1   -   -

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
VISH - Visual observations from Hermosillo (Salvador Aguirre)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
Time - 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
SLE - Sigma Leonids 
PPU - Pi Puppids 
LYR - Lyrids 
NCY - Nu Cygnids 
HVI - h Viriginds 
ETA - Eta Aquariids

April 11 – 20 Meteors

The period of April 11-20 sees a little more diversity as a number of showers become active. Though most are minor, the Lyrids (LYR) are the first major shower since the Quadrantids of early January. Unfortunately, the Lyrids introduce a theme that will be all too common this year, a major shower ruined by bright moonlight.

Obs  Date(UT)      Time    TOT SPO ANT ZCY SLE PPU LYR NCY
SAL3 2011-04-20   09h 11m   15  6   2   -   1   0   5   1
ALLS 2011-04-20   09h 26m   6   4   0   -   0   0   2   0
SAL3 2011-04-19   09h 13m   6   4   0   -   0   0   0   2
ALLS 2011-04-19   09h 43m   10  8   1   -   0   0   1   0
SAL3 2011-04-18   09h 16m   6   6   0   -   0   0   0   0
ALLS 2011-04-18   09h 34m   4   4   0   -   0   0   0   0
SAL3 2011-04-17   09h 17m   7   7   0   -   -   0   0   -
ALLS 2011-04-17   09h 47m   2   1   0   -   -   0   1   -
SAL3 2011-04-16   09h 19m   11  9   1   -   -   0   1   -
ALLS 2011-04-16   09h 49m   5   3   0   -   -   0   2   -
SAL3 2011-04-15   09h 22m   11  11  0   -   -   0   -   -
ALLS 2011-04-15   09h 51m   4   3   1   -   -   0   -   -
SAL3 2011-04-14   09h 24m   5   4   1   -   0   -   -   -
ALLS 2011-04-14   09h 52m   6   4   2   -   0   -   -   -
SAL3 2011-04-13   09h 26m   7   5   2   0   0   -   -   -
ALLS 2011-04-13   00h 41m   2   2   0   0   0   -   -   -
SAL3 2011-04-12   09h 27m   11  8   2   0   1   -   -   -
ALLS 2011-04-12   09h 57m   3   3   0   0   0   -   -   -
SAL3 2011-04-10   09h 30m   13  11  2   0   0   -   -   -
ALLS 2011-04-11   09h 59m   3   3   0   0   0   -   -   -

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
VISH - Visual observations from Hermosillo (Salvador Aguirre)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
Time - 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
ZCY - Zeta Cygnids
SLE - Sigma Leonids
PPU - Pi Puppids
LYR - Lyrids
NCY - Nu Cygnids

T Pyx Brightens Again

Last time we talked about the nova T Pyx it was holding steady around magnitude 7.4 and 7.7. Over the past few days T Pyx has resumed brightening and it currently around magnitude 6.7 to 7.0. If it continues to do as it did in 1966, it should brighten to around magnitude 6.3 over the next 3 weeks.

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