July’s Meteors (plus the 1st 2 days of August)

July is usually one of the best month for meteor observing. This is especially true of the 2nd half of the month as many showers are active including 2 major ones, the Southern Delta Aquariids (SDA) and Perseids (PER). Unfortunately for me July is also the cloudiest month of the year due to our annual monsoon. This month was frustrating for 2 reasons. 1… except for a few days around the 4th, it was mostly cloudy every night resulting in very short clear windows for meteor watching. 2… even though it was cloudy almost every night and the rain was quite close by, it just never seemed to rain at my house until the very end of the month.

With the above in mind, the actually nightly numbers below are not a good measure of the amount of activity that is currently visible. One thing that is apparent from the table is the explosion in the number of active meteor showers as the month of July progressed. Many of these showers are minor and produce only a meteor or 2 per hour. Showers such as the aforementioned SDA and PER as well as the Alpha Capricornids (CAP) and Piscis Austrinids can produce up to 5-10 meteors per hour nightly.

August 1/2 was the last bad weather night. Starting on August 2/3 the monsoon takes a break and the nights are once again clear. This break in the monsoon action will be short lived (by Friday the rain/clouds should be back). The clear weather did give me a chance to test my new camera system which should result in even larger nightly meteor catches. More on that in the next post.

Obs  Date(UT)      Time    TOT SPO ANT CAN JPE CAP PAU PER SDA MUL ATR GDR ZDR
TUS  2010-08-02   01h19m    7   4   0   -   -   1   0   1   1   -   -   -   -
TUS  2010-08-01   00h18m    1   0   0   -   -   0   0   0   1   -   -   -   -
TUS  2010-07-28   00h19m    2   1   1   -   -   0   0   0   0   -   0   0   0
TUS  2010-07-25   00h39m    3   1   0   -   -   0   0   0   2   -   0   0   0
TUS  2010-07-24   02h58m    7   3   0   -   -   0   0   1   0   -   0   0   -
TUS  2010-07-21   02h59m    3   3   0   -   0   0   0   0   0   0   -   -   -
TUS  2010-07-18   00h30m    1   1   0   -   0   0   0   0   0   0   -   -   -
TUS  2010-07-17   02h12m    4   3   0   0   0   0   0   0   -   -   -   -   -
TUS  2010-07-13   02h29m    10  9   0   0   1   0   -   -   -   -   -   -   -
TUS  2010-07-12   01h59m    7   7   0   0   0   0   -   -   -   -   -   -   -
TUS  2010-07-10   00h19m    1   0   1   0   0   -   -   -   -   -   -   -   -
TUS  2010-07-09   01h17m    2   2   0   0   0   -   -   -   -   -   -   -   -
TUS  2010-07-08   00h16m    1   0   0   1   0   -   -   -   -   -   -   -   -
TUS  2010-07-07   05h53m    14  12  1   1   -   -   -   -   -   -   -   -   -
TUS  2010-07-06   07h55m    10  9   1   -   -   -   -   -   -   -   -   -   -
TUS  2010-07-05   07h54m    17  16  1   -   -   -   -   -   -   -   -   -   -
TUS  2010-07-04   07h53m    19  18  1   -   -   -   -   -   -   -   -   -   -
TUS  2010-07-03   01h34m    7   7   0   -   -   -   -   -   -   -   -   -   -
TUS  2010-07-02   05h44m    2   1   1   -   -   -   -   -   -   -   -   -   -
TUS  2010-07-01   07h31m    7   5   2   -   -   -   -   -   -   -   -   -   -

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
CAN - c Andromedids
JPE - July Pegasids
CAP - Alpha Capricornids
PAU - Piscis Austrinids
PER - Perseids
SDA - Southern Delta Aquariids
MUL - Mu Lyrids
ATR - Alpha Triangulids
GDR - Gamma Draconids
ZDR - Zeta Draconids
AUP - August Piscids

Meteor Activity Outlook for July 31-August 6, 2010

[I have been very lax lately in my posting of Bob’s weekly Meteor Activity Outlooks. I’m sorry for that. Here’s this weeks installment and I’ll try to keep up in future weeks.]

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.

After several months of low activity the meteor rates for both hemispheres see a marked increase in July. In the northern hemisphere the change is not noticeable until mid-month when several southern radiants, the Perseids, and sporadic rates all increase in activity. Southern rates are good all month long.

During this period the moon reaches its last quarter phase on Tuesday August 3rd. At this time the moon will be located 90 degrees west of the sun and will rise near 0100 local daylight time (LDT) for those located in the mid-northern latitudes. This weekend the waning gibbous moon will be in the sky most of the night making it difficult to view any meteor activity. As the moon passes its last quarter phase the situation improves as long as one observes with the the moon far from their field of view. The estimated total hourly rates for evening observers this week is ~4 no matter your location. For morning observers the estimated total hourly rates should be ~17 from the northern hemisphere and ~21 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. During this period, moonlight reduces activity seen during the morning hours.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning July 31/August 1. 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:

Alpha Capricornids (CAP)

The Alpha Capricornids (CAP) are active from a wide radiant located at 20:30 (307) -09. This position lies in northwestern Capricornus, two degrees northeast of the third magnitude double star Alpha Capricornii. The radiant is best placed near 0100 local daylight time (LDT), when it lies on the meridian and is highest in the sky. Current rates should be ~2 per hour as seen from the northern hemisphere and ~3 per hour from the southern. Don’t confuse these meteors with the antihelion meteors, which have a radiant just to the east. Both radiants need to be in your field of view to properly sort these meteors. With an entry velocity of 25 km/sec., most activity from this radiant would be slow, a bit slower than the antihelions. This radiant is well seen except for far northern latitudes where it remains twilight all night long and the radiant does not rise as high into their sky.

Antihelions (ANT)

The wide Antihelion (ANT) radiant is now centered at 21:24 (321) -13. This area of the sky lies in northern Capricornus. The nearest bright star is fourth magnitude Iota Capricornii, which lies three degrees to the southwest. 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 northwestern Piscis Austrinus, Microscopium, Capricornus, western Aquarius, or southeastern Aquila could be a candidate for this shower. Rates at this time should be ~2 per hour as seen from the northern hemisphere and ~3 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.

Delta Aquariids (SDA)

The Delta Aquariids (SDA) reach maximum activity on Friday July 30th. Unfortunately the bright moon will obscure most of the activity from this shower. The radiant is located at 22:48 (342) -16. This position lies in southwestern Aquarius, just west of the third magnitude star Delta Aquarii. The radiant is best placed near 0300 LDT, when it lies highest in the sky. The optimal latitudes for viewing this shower lie in the southern tropics where the radiant passes overhead. With an entry velocity of 42 km/sec., most activity from this radiant would be of average velocities.

August Piscids (AUP)

A new shower discovered by Sirko Molau and Juergen Rendtel from the IMO’s video database are the August Piscids (AUP). This shower is only active on eight nights from August 2-9 with maximum activity occurring on the
4th. At maximum, the radiant is located at 00:30 (008) +18. This area of the sky is located in western Pisces, four degrees northwest of the third magnitude star Algenib (Gamma Pegasi). This position is also suspiciously close (15 degrees east) to the radiant of the 1970’s radiant known as the Upsilon Pegasids. Little has been reported of this radiant recently. This radiant is best placed during the last hour before dawn when it lies highest in a dark sky. Hourly rates are expected to be less than 1. With an entry velocity of 66 km/sec., the average August Piscid meteor would be swift.

Perseids (PER)

The Perseids (PER) are active from a radiant located at 02:03 (031) +55. This position lies in western Perseus, twelve degrees north of the famous second magnitude double star Almach (Gamma Andromedae). The radiant is
best placed during the last hour before the start of morning twilight when it lies highest in a dark sky. Current rates would be 2-3 per hour at best, as seen from the northern hemisphere. Activity from this source is not visible south of 40 degrees south latitude. With an entry velocity of 61 km/sec., most activity from this radiant would be swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately five 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 fourteen 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 slightly 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
CAP Alpha Capricornids   20h 30m  -09    25     2     3
ANT Antihelions          21h 00m  -15    30     2     3
SDA Delta Aquariids      22h 48m  -16    42     3     5
AUP August Piscids       00h 30m  +18    66    <1    <1
PER Perseids             00h 44m  +51    61     3     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

2008/2009 – The Past 2 Years of Video Meteors

10,102… that’s the number of meteors detected by my 2 camera systems since the start of observations in late February 2008 till the end of 2009. It’s amazing how quickly the numbers add up.

The high number is a testament to the clear dark sky over Tucson. Over all of 2009, I was able to detect meteors on 287 nights. That number could even have been higher if not for a few weeks when the cameras were left off. Hopefully I’ll be able to break 300 nights this year, though our active El Nino winter is resulting in a slow start.

My systems (as well as Bob’s) are part of an international group of video meteor observers using Sirko Molau’s MetRec meteor detection software. Last year this group, the IMO Video Meteor Network, consisted of 24 observers from 10 countries operating 43 camera systems. Every month Sirko publishes a summary of the previous month’s observations while the December summary also presents statistics on the entire year’s data. The IMO Video Meteor Network monthly summaries can be found here. Personally, I find them a great read and can’t wait for their release. Sirko does great work and the network would never have happened without him. Thanks, Sirko!

Below is a table breaking down my results by month. Nights, hours and meteors per month are listed. Even further down is a graph of nightly detections covering an entire year from March 2008 to February 2009. During this time only a single camera was used and for the most part, very little was changed. The camera, lens, position on the sky and MetRec code parameters were constant giving an accurate measure of the variation in meteor activity throughout the year. Note the weather has not been accounted for and results in low rates for some nights such as the monsoon months of July and August. Rather than looking like 5th or 6th best shower, the Perseids (PER) should be the best shower of the year. Also notice the rather broad maximum for the Orionids (ORI) versus the very short maximum of the Quadrantids (QUA). Other showers highlighted on the plot are the Lyrids (LYR), Southern Delta Aquariids (SDA), Leonids (LEO) and Geminids (GEM).

              SALSA1               SALSA2
Month  Nights Hours Meteors Nights Hours Meteors
2008
JAN      --    ---    ----    --    ---    ----
FEB       1      3       5    --    ---    ----
MAR      25    212     232    --    ---    ----
APR      29    221     305    --    ---    ----
MAY      22    151     191    --    ---    ----
JUN      23    168     255    --    ---    ----
JUL      15     73     229    --    ---    ----
AUG      20    117     357    --    ---    ----
SEP      29    224     460    --    ---    ----
OCT      30    304    1071    --    ---    ----
NOV      28    259     596    --    ---    ----
DEC      25    174     444    --    ---    ----
Total   247   1906    4145    --    ---    ----
2009
JAN      26    198     443    --    ---    ----
FEB      24    144     207    --    ---    ----
MAR      25    152     201    --    ---    ----
APR      26    136     192    --    ---    ----
MAY      26    134     195    --    ---    ----
JUN      22     73      97    18     65      93
JUL      23     75     148    23     87     225
AUG       9     33      74     8     36      91
SEP      27    122     202    26    167     434
OCT      26    180     692    27    192     919
NOV      26    128     439    25    155     643
DEC      27    127     364    12     74     298
Total   287   1502    3254   139    776    2703

August 4/5/6/7 Meteors

After a couple nights of rain and clouds, it has cleared out again in Tucson. Last night was probably a nice night of meteors but I forgot to turn my cameras on.

Luckily Bob has better luck and a better memory in SDG. From Bob’s notes: “After a couple of partly cloudy nights, skies cleared enough to allow observations from home. Fog rolled in just before the start of twilight, ending the session 15 minutes prematurely. No Delta Aquarids were recorded tonight, which is strange as this shower continues for at least another week.”

Obs Date (UT)  TotTime TOT SPO ANT CAP SDA PER KCG
TUS 2009-08-07 00h 00m  Forgot to turn on cameras!
TUS 2009-08-06 00h 00m  Clouds all night
SDG 2009-08-06 07h 15m  30  11  2   3   2   11  1
TUS 2009-08-05 00h 00m  Clouds all night

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
SPOSporadics (meteors not affiliated with any particular meteor shower)
ANT – Antihelions
CAP – Alpha Capricornids
SDA – Southern Delta Aquariids
PER – Perseids
KCG – Kappa Cygnids


July 30/31 Meteors

Yet another great night of above average meteor totals. In Tucson the sky was better and as a result I was able to detect 61 meteors. The Southern Delta Aquariids continue to produce rates consistent with their peak. Surprisingly, the Perseids are putting on a good show even though we are 2 weeks from their max.

From Bob’s notes: “I observed another four hours this morning. The sky did not appear quite as dark as the previous night but there were no high clouds present tonight. Rates were down compared to last night, especially for the sporadic meteors.”

Obs  Date (UT)   TotTime TOT SPO ANT CAP SDA PAU PER
TUS  2009-07-31  06h 48m  61  24  4   4   14  1   14
SDG  2009-07-31  04h 00m 102  54  2   3   24  1   18

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
SPOSporadics (meteors not affiliated with any particular meteor shower)
ANT – Antihelions
CAP – Alpha Capricornids
SDA – Southern Delta Aquariids
PAU – Piscids Australids
PER – Perseids

July 29/30 Meteors

Rates were down last night. There are 2 possible reasons for this. One, we have passed the peak of the Southern Delta Aquariids and activity should slow for the rest of the week. Two, sky conditions in Tucson weren’t as good as the previous night as an influx of moisture made for some murky skies. It is likely that it was a combination of the 2.

Bob was able to take his meteor camera to a dark site allowing him to detect a lot more meteors than usual. From his notes: “I took the camera to dark skies and to get away from the low clouds that have been present along the coast for the past few nights. Alpine lies in the foothills of the Laguna Mountains some 25 miles east of San Diego. The low clouds acted like a blanket over the lights of San Diego and it was actually very dark. Activity was impressive both visually and through the camera. There were a few high clouds present at times, but not enough to spoil the display.”

Obs  Date (UT)   TotTime TOT SPO ANT CAP SDA PAU PER
TUS  2009-07-30  08h 26m  39  18  1   2   12  0   6
SDG  2009-07-30  04h 00m 130  74  5   2   30  1   18

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
SPOSporadics (meteors not affiliated with any particular meteor shower)
ANT – Antihelions
CAP – Alpha Capricornids
SDA – Southern Delta Aquariids
PAU – Piscids Australids
PER – Perseids

July 28/29 Meteors

Late July is usually a time of rain showers in southern Arizona. Instead, we have been witnessing showers of a different nature. The Southern Delta Aquariids and the Alpha Capricornids are currently at their peak level of activity. These 2 showers may be producing many of the recent meteors being observed by many of you (based on your comments).

It is surprising (to me at least) how many Perseids have been detected lately. This shower is one of the best and is known to be active for many weeks before its maximum. Still with maximum 2 weeks away, the current level of activity is very encouraging. Unfortunately, the Moon will a problem during the time of the Perseid peak. Still, moon or no moon, this is always a good shower to observe.

Obs  Date (UT)   TotTime TOT SPO ANT CAP SDA PAU PER
TUS  2009-07-29  07h 48m  57  20  4   3   18  1   11

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
SPOSporadics (meteors not affiliated with any particular meteor shower)
ANT – Antihelions
CAP – Alpha Capricornids
SDA – Southern Delta Aquariids
PAU – Piscids Australids
PER – Perseids

Follow

Get every new post delivered to your Inbox.

Join 107 other followers