New Comet Found the Old Fashioned Way

Don Machholz of Colfax, CA found his 11th comet on the morning of Tuesday, March 23rd. What sets Don’s 11 discoveries apart from the other comets found recently is the way it was found. Nowadays comets are found by computers analyzing thousands of digital images. Only after the computers have sorted through the data is there human intervention to confirm that the object being flagged as a comet is really a comet. Don, on the other hand, has found all 11 of his comets the old-fashioned way. With no help from computers or digital cameras, Don finds his comet by peering through his telescope and identifying faint fuzzies that shouldn’t be there. In fact, it is the first visual discovery of a comet since late 2006.

Comet C/2010 F4 (Machholz) is currently 11th magnitude. At this brightness, only observers with moderate-sized telescopes under dark skies will see it. Though the orbit is still somewhat uncertain, the comet appears to reach perihelion in early April at a distance of ~0.6 AU from the Sun. Unfortunately, it will not get much brighter. In fact, seeing it will only get more difficult as the comet moves closer to the Sun. Its increasing proximity to the Sun and the bright Moon now located in the morning sky means even advanced observers will have a hard time seeing it after a few days. It is possible the comet may only be observed for a week or so and then lost for the ages.

Orbit of Comet C/2010 F4 (Machholz) and the inner planets. Created with C2A. Credit: Carl Hergenrother/C2A.

The image above shows the orbit of the comet. With an inclination of ~90 degrees, its orbit is perpendicular to the orbits of the planets which is not unusual for a long-period comet. The big question is how was this comet missed by all of the professional asteroid/comet surveys. Nowadays most comets are found while very faint (17-19th magnitude) and a few years before perihelion. This comet probably escaped detection because it was located near the Milky Way for the past year. The Milky Way is so full of stars that the current crop of asteroid/comet surveys have a difficult time finding any objects there. As a result, many surveys avoid the Milky Way all together.

Congrats to Don Machholz! And thanks for showing us that persistence (he hunted for 607 hours since his last find in 2004) and old-fashioned comet hunting can still pay off in this era of computers and automation.

Meteor Activity Outlook for March 27-April 2, 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.

March is the slowest month for meteor activity. No major annual showers are active and only two very weak minor showers produce activity this month. The sporadic rates continue a slow decline as seen from the mid-northern latitudes and mid-southern rates reach a first half minimum. There is not much to look forward to this month expect for the evening fireballs that seem to peak this time of year from the northern hemisphere. This could be due to the fact the antapex radiant lies highest above the horizon this time of  year during the evening hours.

During this period the moon reaches its full quarter phase on Tuesday March 30.  At this time the moon lies opposite the sun in the sky and rises as the sun sets and sets as the sun rises. This weekend there is a small window of time between moonset and the start of morning twilight when the sky is favorable for meteor watching. 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 ~5 from the northern hemisphere and ~7 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.

Shower descriptions will be presented next week when the moonlight conditions
have improved.

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          13h 20m  -09    30     1     1
ZSE Zeta Serpentids      17h 32m  -03    64    <1    <1
ZCY Zeta Cygnids         19h 40m  +38    44    <1    <1

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

Mar 20/21 to 25/26 Meteors

Nightly meteor rates remain low as there are no major active showers and the background Sporadic rate is near a yearly minimum. Rates were also depressed as a weak winter storm passed through the area, Though the storm only produced a few hundredths of an inch of rain, the clouds it produced affected observing for 3 nights.

Obs  Date(UT)      Time    TOT SPO ANT GNO ZSE
TUS  2010-03-26   09h 18m   7   7   0   -   0
TUS  2010-03-25   10h 05m   12  10  1   -   1
TUS  2010-03-24   06h 26m   6   6   0   -   0
TUS  2010-03-23   02h 58m   1   1   0   0   -
TUS  2010-03-22   08h 35m   5   4   1   0   -
TUS  2010-03-21   10h 13m   11  9   2   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
GNO - Gamma Normids
ZSE - Zeta Serpendids

Mar 17/18/19/20 Meteors

Activity has been fairly consistent from night to night with anywhere from 10-16 meteors per night. Though a single minor shower, the Gamma Normids, is active none have been seen. This isn’t too surprising since this shower only produces a meteor or 2 per hour for observers who can see down to 6th magnitude. My cameras are much less sensitive than the human eye and can only see down to ~2nd magnitude. Also the radiant of the Gamma Normids is located in the far southern sky so it takes a rare one to be seen this far north.

The highlight of the past 3 nights was a bright short lived fireball seen on the evening of March 17 at 10.:51 pm (March 18 @ 5:51 UT). This fireball lasted for a little over 1 second but traversed only a small part of the sky. The whole event was caught by SALSA2, my small FOV zenith-pointing camera as well as the all-sky cam at  the MMT on Mount Hopkins. For some reason my all-sky camera did not record the event. Makes me wonder how many other bright meteors are being missed.

The video below is from the SALSA2 camera.

The next image is a screen shot of the all-sky camera at the MMT. This image is a ~10-second exposure so unfortunately we can’t get any video.

March 18 fireball from all-sky cam on Mount Hopkins. Credit: MMTO/SAO/Univ. of Arizona.

We can learn a surprising amount of information about this fireball just from the above images. The shareware program Fireball writen by Albino Carbognani (www.fis.unipr.it/~albino/ITASN/documenti/fireball.html) can be used to determine the trajectory through the atmosphere as well as an initial orbit.

Start Height = 71.7 km
End Height  = 67.7 km
Total Length of Travel = 15.7 km

Geocentric Velocity = 12.1 km/s

Semi-major axis = 0.82 AU
Eccentricity = 0.22
Inclination = 0.6°
Perihelion = 0.64 AU
Aphelion = 1.00 AU

The object  that caused the fireball was an Aten. This means it had crossed the Earth’s orbit and had a semi-major axis (its average distance from the Sun) less than 1.0 AU. The very slow geocentric velocity of ~12.1 km/s is almost as slow as a meteor can get (the slowest is 11.2 km/s, the fastest is ~72 km/s). The slow velocity is a result of impacting the Earth near the objects aphelion point. Note of warning, there is still much uncertainty in the positions and timing of this fireball. The orbit below is probably not exactly correct. Still, it is hard for this object to have been on an orbit other than an Aten with an aphelion near 1 AU. That much is certain. The perihelion distance, on the other hand, can be a few tenths of an AU larger or smaller.

Orbit of the Tucson fireball seen on March 18. Created with C2A and Fireball. Credit: Carl Hergenrother.

Obs  Date(UT)      Time    TOT SPO ANT GNO
TUS  2010-03-20   10h 16m   14  12  2   0
TUS  2010-03-19   09h 35m   16  14  2   0
TUS  2010-03-18   10h 19m   10  9   1   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
GNO - Gamma Normids

Mar 15/16/17 Meteors

In the previous post I showed images of a bright fireball seen Sunday evening over Tucson. At the same time a bright fireball was seen in northern California. At first I wondered if the two might have been related, or even the same fireball. Thanks to recent analysis of video data in California by  the Sierra College, we have our answer. No, the 2 fireballs are not the same and also are not related. More info on the March 15 CA fireball can be found here.

Obs  Date(UT)      Time    TOT SPO ANT GNO
TUS  2010-03-17   10h 15m   15  13  2   0
TUS  2010-03-16   10h 07m   13  8   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
GNO - Gamma Normids

Mar 13/14/15 Meteors

Talk about nights at different extremes. Two nights ago had to rank as one of the most boring nights of the past 2 years. Not only were a small number (6) of meteors seen by my deep camera, no meteors were seen by my wide-angle fireball camera. For a clear night you should see at least 3 or 4 bright ones.

Last night (Sunday, March 14) was better. What really set it apart was a bright fireball seen over Tucson at ~10:14 pm (5:14 UT). Both of my cameras picked it up. The first movie shows the very early stages of the fireball. Since the SALSA2 camera only has a FOV of about 50×70 degrees, this camera was lucky to see any of it. In the movie the fireball is moving nearly due north (north is to the bottom) and first becomes visible just to the north of Leo.

In the next view, we are looking at images from a camera with a much wider FOV. Here the fireball continues to brighten as it moves towards the North. It is still brightening as it moves out of the FOV (about 20-30 degrees elevation). The apparent skipping motion is due to my computer dropping frames. Guess I need a better system…

The near-all-sky cam on Mount Hopkins caught another view of the fireball. Hopkins is located to the south of my place so the fireball appeared further north.

MMT all-sky camera on Mount Hopkins. Credit: Tim Pickering/University of Arizona.

The fireball was also seen on all-sky cameras in Sierra Vista and on Mount Lemmon. Interestingly, a brilliant fireball was observed to the west of Sacramento, CA at almost exactly the same time. The jury is out as to whether the AZ and CA fireballs are one and the same since they could easily be unrelated. If anyone witnessed the fireball, especially observers to the north of Tucson, leave a comment and let us know. Let’s hope tonight brings another one.

Obs  Date(UT)      Time    TOT SPO ANT GNO
TUS  2010-03-15   10h 25m   13  10  3   0
TUS  2010-03-14   08h 47m   6   6   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
GNO - Gamma Normids

Mar 5/6 to 12/13 Meteors

Now I’m finally caught up.

The winter rainy season is letting up for a weeks or so and my zenith pointing camera is finally bolted down (so no more mystery shifts which make astrometry difficult), so now we just need some nice meteor displays. Rates are low in March and should remain low for another month.

Obs  Date(UT)      Time    TOT SPO ANT DLE GNO
TUS  2010-03-13   10h 30m   8   7   1   -   0
TUS  2010-03-12   09h 52m   10  10  0   -   0
TUS  2010-03-11   00h 30m   1   1   0   -   0
TUS  2010-03-10   07h 26m   8   6   2   0   0
TUS  2010-03-09   07h 52m   8   8   0   0   0
TUS  2010-03-08   00h 00m   Bad Weather - No Meteors
TUS  2010-03-07   01h 54m   4   2   1   1   0
TUS  2010-03-06   04h 00m   9   7   1   1   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
DLE - Delta Leonids
GNO - Gamma Normids

Feb 22/23 to Mar 4/5 Meteors

Still catching up here. As you can see from the low nightly totals, the weather has really played havoc on observing. Unfortunately rates are usually low this time of the year so even if it were clear there’s little to see.

Obs  Date(UT)      Time    TOT SPO ANT DLE GNO
TUS  2010-03-05   09h 52m   15  12  2   1   0
TUS  2010-03-04   10h 05m   9   7   1   1   0
TUS  2010-03-03   10h 50m   7   6   0   0   1
TUS  2010-03-02   10h 52m   3   2   0   1   0
TUS  2010-03-01   00h 11m   1   1   0   0   0
TUS  2010-02-28   04h 58m   0   0   0   0   0
TUS  2010-02-27   04h 34m   8   6   2   0   0
TUS  2010-02-26   10h 18m   16  13  1   2   0
TUS  2010-02-25   00h 25m   1   1   0   0   0
TUS  2010-02-24   10h 52m   4   4   0   0   -
TUS  2010-02-23   09h 31m   9   7   2   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
DLE - Delta Leonids
GNO - Gamma Normids

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

Meteor Activity Outlook for March 6-12, 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.

March is the slowest month for meteor activity. No major annual showers are active and only two very weak minor showers produce activity this month. The sporadic rates continue a slow decline as seen from the mid-northern latitudes and mid-southern rates reach a first half minimum. There is not much to look forward to this month expect for the evening fireballs that seem to peak this time of year from the northern hemisphere. This could be due to the fact the antapex radiant lies highest above the horizon this time of  year during the evening hours.

During this period the moon reaches its last quarter phase on Sunday March 7th.  At this time the moon lies ninety degrees west of the sun and rises near midnight local standard time (LST). The moon will be a nuisance this weekend, but as the week progresses, its impact lessens. 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 ~7 from the northern hemisphere and ~9 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 March 6/7. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

Antihelions (ANT)

The wide Antihelion (ANT) radiant is now centered at 11:56 (179) -01. This area of the sky lies in western Virgo, three degrees southeast of the fourth magnitude star Beta Virginis. This radiant is best placed near 0100 local standard time (LST) 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 Leo, Sextans, Crater, or Virgo could be a candidate for this shower. Rates at this time should be ~2 per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

Gamma Normids (GNO)

The Gamma Normids (GNO) is a weak shower best seen from the southern hemisphere. This shower is only visible south of forty degrees north latitude. The further one is located south (down to 50S) the better the radiant is situated in the sky. Expected rates from the southern hemisphere is only 1 per hour, even with the radiant located high in the sky. The current radiant position lies at 16:12 (243) -52. This position lies in central Norma, two degrees southwest of the fourth magnitude star Gamma Normae. The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. At 56km/sec. the Gamma Normids would produce mostly swift meteors.

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          11h 56m  -01    30     2     2
GNO Gamma Normids        16h 12m  -52    56    <1     1

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
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