Classic Impact Alert Notices and Archives

Lunar Meteor Impact Candidate Observations 2006-2008

So far, I have received reports of 5 Lunar Perseid impact candidates, all made on 9 August 2008UT. As the Perseid shower winds down, I want to bring to your attention some impact candidates that were recorded last week. We saw some moon-based activity early on, with two bright candidates and two secondary candidates being recorded on August 9UT. Robert Spellman recorded a bright impact at 4:06:22UT, which can be seen at this site: http://www.angelfire.com/space2/robertspellman/observationarchive.html. George Varros recorded a bright impact at 2:27:04UT, whose image appears here: http://www.lunarimpacts.com/ 022704_candidate .jpg. He also reports two additional (though not definite, yet) candidates at 1:59:46 and 2:18:18. If anyone was observing the moon during these times, please check your recordings for these impacts. You can look at the above images to find out where they occurred.

Four impact candidates from the Quadrantid stream have been published online by the NASA/MSFC group, including one event lasting 10 video frames. This long event took place at 11:42:39UT, 4 January 2008, so observers are asked to check tapes for this event. Three fainter events, each lasting 1 to 2 frames, but observed through 2 or 3 telescopes simultaneously, also have been reported. I also have a report of up to 10 Geminid impact candidates, several confirmed already, observed in Japan during the December annual shower. Images of several of these events are provided on the web page: http://www.yanagi.ice.uec.ac.jp/luna_e.html. Observers who recorded the Moon during the recent Geminid opportunity are asked to check their tapes and records for signs of impacts.

NASA-MSFC effort now has 112 impact candidates (as of July 15, 2008). The dates, times, selenographic coordinates, and source (sporadic or shower) are included in the table on their home page (link below). Observers are encouraged to carefully check their videotapes near these dates/times for corroborating impact signatures. Please visit http://www.nasa.gov/centers/marshall/news/lunar/index.html for information on these impact candidates. The number of impacts recorded by this group serves as a reminder that these events are happening on a regular basis and is a motivator for individuals to keep up the observations in support of this and lunar meteor work in general. The locations of the candidates on the lunar surface can be viewed on the above link.

Mr. George Varros reports the observations of impact candidates, from the Orionid and Geminid meteor showers, and each remains to be confirmed. If anyone happened to be observing / videotaping the moon at the times listed below, please check your records / tapes for one or more of these events. In addition, Mr. Varros requests the assistance of another individual or individuals in the Eastern U.S. to videotape the moon concurrently with him to increase the likelihood of confirmation of impact events. The information concerning the impact candidates follow:

Images of the following impact event candidates can be seen at http://www.gvarros. com/
10/20/2007
23:17:03UT #a21 2 frames 3 fields bright
23:23:48UT #b4 2 fields not that bright
23:43:14UT #d3 3 fields

10/21/2007
00:47:53UT #e58 3 video fields
01:03:05UT #f37 1 frame

02:52:46UT duration = 2 video fields Image

03:41:23UT one video field only
03:48:12 #i3 2 fields

12/15/2007

00:45:51UT - 2 It is one frame in duration and both odd and even field are similar in brightness.

12/18/2007

00:38:31.107UT 2 frames, 3 fields, bright
01:08:41UT 1 1 frame, 2 fields, very dim
02:13:47UT 1 1 frame, 2 fields, suspect cosmic ray due to anti-aliasing of the even video field

Two candidate Lunar Lyrid impacts are presented at http://www.gvarros.com/. The first was recorded at 3:12:24UT on 22 April 2007, and the second at 1:17:35 on 23 April 2007. Observers are strongly encouraged to check tapes at these times for validating imagery. Two of the Lyrid impacts have been confirmed by remote observers: George Varros in Maryland and Dave Clark in Texas. Congratulations and keep up the excellent work!

Maurice Collins reports a bright impact flash candidate from New Zealand which he observed at 5:52UT on 8 December 2006 (uncertainty in observation of +/-2 min). He described the event as follows: “Was just observing the moon half and hour ago in daylight and saw a very bright flash in the centre of the lunar disk at 0552UT +- 2mins. Extremely bright. Can't really believe it was real, but that is what I saw. South of Godin. Flared up and down over a fraction of a second. Estimate it to being about 3 times brighter than the moon background itself. Can't reproduce it, so either in my eye itself or on the Moon. Using 40mm A.H. eyepiece at time on my 3.5" Mak. Seeing was III-IV Antonadi scale. I will report it as that is what I definitely saw, made me go "whoa!", but wouldn't expect it to be an actual impact unless someone else in say Australia reports it too. Though I have no other explanation at this time.”

SMART-1 Project Wrapup-Sept. 2006

One amateur astronomer, Peter Lipscomb, recorded an apparent impact flash of the SMART-1 spacecraft; more information can be seen at his website: http://cosmonut.org/SMART-1.htm

Of 25 reports that I had received of the impact, 1 reported a positive event (mentioned above), 14 reported a clear view of the moon but no impact signature, and ten were clouded out. The negative reports were made with apertures ranging from 8 to 12 inches, with one 36-inch scope used (George Observatory, Brazos Bend State Park, south of Houston, Texas)

The SMART-1 spacecraft impacted the Moon as expected on 3 September 2006 at 5:42:15UT. The impact occurred after the spacecraft approached at an angle of 1 degree with the level surface. The spacecraft collided with the Moon at a speed of 4,500 mile per hour (7,200 km / h). Observers on the 3.6 meter Canada-France-Hawaii telescope in Hawaii recorded a bright flash in the Infrared. In contrast, nearly all amateur astronomers who had clear skies for the event and a clear view of the Moon were not able to see anything. The impact was likely too faint in the visible for most amateurs to observe in small to moderate instrumentation (this includes both the flash itself and any dust cloud that resulted from the impact. There is one notable exception to the lack of amateur footage of this event, with Peter Lipscomb of Santa Fe, New Mexico, recording the impact on video through an 8-inch telescope. The following web links contain much more information about the impact event (Note…some of these may become inactive or outdated over time):

CFHT in Hawaii-their Press Release: http://www.cfht.hawaii.edu/News/Smart1/

The ESA Press Release: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39961

Science @ NASA (Pre-Impact): http://science.nasa.gov/headlines/y2006/30aug_smart1.htm

The website that contains the information about the impact location, etc. can be seen via the links below, which is the homepage of the SL/REA SMART-1 Lunar Impact Project, in the Lunar Section of the Rede de Astronomia Observacional REA – BRAZIL Results of the impact experiment are posted here as well.

English Version: http://slrea-smart1lunar-impact-project-ing.blogspot.com/

Portuguese Version: http://www.slrea-smart1lunar-impact-project.blogspot.com/

Spanish Version: http://www.slrea-smart1lunar-impact-project-esp.blogspot.com/

REA Brasil Lunar Section : http://www.reabrasil.org/lunar/smart1impact.htm

Lunar Impact Candidate Reports-2005

NOTE: I have completed a comprehensive and better organized catalogue of impact candidates received to date. It is in pdf format and has 15 pages of text and includes all of the candidates reported to ALPO and IOTA from 1999 to 2004. Images of the 1999 Leonid impacts courtesy of David Dunham and IOTA. This catalog is a portion of the observing manual “An Observer’s Guide to Lunar Meteoritic Phenomena” which is currently in the final stages of preparation. Click here to view the catalog. The reports provided below are of candidates reported since September of 2004, and all of these are, as of late, unconfirmed.

12 August 2005

A Lunar Perseid Candidate was observed at 3:33:08UT, 12 August 2005. by Robert Spellman, who was monitoring the Moon by video from 2:35UT to 4:40UT. His website contains images of the candidate: http://www.angelfire.com/space2/robertspellman/perseid2005.html

Other attempts for Lunar Perseids were made by Chad E. as follows:

2:53 - 3:02 UT on August 10th, 2005

2:37 - 3:28 UT on August 11th, 2005

2:49 - 3:34 UT on August 12th, 2005

No candidates are reported from these attempts. In addition, Masayuki Ishida writes that he observed the Moon from 10:50 to 11:40 UTC on 2005 Aug 12 with video, but he did not detect any lunar meteor impact candidates.

12 July 2005

On July 12, 2005, at 9:18 EDT (1:18 July 11 UT) a Bright flash, estimated brighter than Jupiter (about -3 or -4 magnitude) was observed in the northern hemisphere of the moon's earthshine with the naked eye. Possibilities of its nature include a point meteor or optic flashes, but the observer reported that the event “certainly looked real”. The sky was overcast with thick cirrus, with only the Moon and Jupiter visible at the time of the observation. The observer’s name was William Watson, who observed it from the U.S.

The characteristics of the event are as follows:

1) Flash duration ~0.5 sec

2) No motion detected

3) Observer location: City of Tonawanda (north of Buffalo, NY)

4) The flash was seen with the naked eye

14 April 2005

On 14 April 2005 at 18:32.5UT, an observer with the UAI observed a bright, long duration impact candidate event near the crater Archimedes. Anyone observing the moon within a few minutes of this time is asked to submit any observations, positive or negative, to the Coordinator (note that a valid negative observation or two would likely rule out an impact event and enable consideration of other causes to be made).

12 February 2005

An observer from Minneapolis, MN observed an impact candidate at 0:13UT on 12 February 2005. The observer, Peter Jevne, wrote: “[From] Minneapolis, while viewing the moon through six inch binoculars I observed a bright flash on the dark portion. It looked like a 4th Mag. star blinking on and then off”. Several days later, Roger Venable reported a similar observation at a similar time: “I thought I saw a momentary flash on the dark side of the moon, and I immediate thought, "Sheesh! That looked just like the video of a flash of a meteor impact that I have," that I recorded in the 2001 Leonid shower. It seemed to me to be too rare an event to believe my eyes -- after all, it lasted only a small fraction of a second. Besides, I considered it to be too bright, about 1st or 2nd magnitude in consideration of the proximity to the sunlit crescent, to be a true meteor strike. I am certain of the date, and of the twilight condition, but I did not check the time. It was late twilight. My guess is that it was near the end of nautical twilight, which ended at 00:08 UT on February 12 as seen from my location. This guess is approximate. I leave it to others to decide whether the error of such an estimate spans the time of 00:13 reported by Peter Jevne."

Roger continues with a helpful description of the location of the event: “Here is my description of where on the lunar surface the flash occurred. Imagine a crescent that is only 12.3% illuminated, so that the width of the sunlit portion is only one eighth of the diameter of the moon. The crescent was nearly horizontal, so that the northern cusp was at only slightly greater altitude than the southern. The flash occurred slightly to the left of the midline, about one third of the way from the edge of the sunlit portion to the dark limb. This puts it at roughly 6 degrees south latitude and 17 degrees east longitude (IAU convention) on Luna. Like the estimate of the time, this position estimate is approximate.”

If you have observed the Moon during this time, for Lunar Geminid impacts, or for any other event, please report, even if you observe nothing. Null observations are valuable in that they establish upper limits to the size and/or frequency of impacts from a given source (to also include all other sources, but to a lesser extent, since they would contribute far fewer impactors).

Lunar Leonid Impact Candidates-November 2004

At least one observer has recorded several impact candidates from the 2004 Leonid meteor shower. Although the shower was much less spectacular than in recent years, the combination of high velocity and higher-than-normal Zenithal Hourly Rate potential, along with a favorably positioned Moon, made for a decent opportunity to observe the moon for meteoroid impacts. This web page has images and details of the impact candidates:

http://www.geocities.com/xetor_2000/impact.html

Observers are encouraged to check their tapes and records for these or additional impact candidates.

Several observers have videotaped the Moon during the recent total lunar eclipse, but no impact candidates have been reported.

Lunar Perseid Impact Confirmed in Japan-August 2004

A team of astronomers in Japan have confirmed the impact of a (likely) Perseid meteor on the Northwest edge of the Moon on 11 August 2004. This is the first non-Leonid impact confirmed to date. Check out the following website for more details:

http://www.yanagi.ice.uec.ac.jp/luna_e.html

Anyone who has observed the moon for lunar Perseids and / or video taped the moon are encouraged to check their data / tapes for more events.

Infrared Lunar Meteor Observations & More

Is is possible that someone has observed lunar Leonids in 1997? At least one observer in Florida has been observing lunar meteor impacts since 1997, observing in the near-infrared (800-1100nm). Impact flashes are much brighter in the infrared than the visible, and anyone who is equipped with a Wratten 87 filter and a low-light video camera sensitive at these wavelengths is encouraged to observe the Moon during the Earthshine periods. Click here to read more about Allan Kimble's work.

Infrared Observations in the 5-micron and 10-micron range are especially encouraged during the 2002 November Leonids event, since a Full Moon at this wavelength will appear dim compared to the brightness of Leonid impacts. The eastern half (celestial coordinates) is the half of the moon to watch during this event (see the lunar impact plots).

Anyone who is interested in being included on the impact mailing list is encouraged to e-mail the Coordinator, who will then send an invitation to join the lunar-impact Yahoo! group. This is a group whose purpose is to share ideas and observations and general comments concerning the lunar meteor phenomena.

There's an excellent article online that describes what happens on the Moon when a sizable Leonid meteoroid impacts. Click here to read about the dynamics of the explosions produced by Leonid meteoroids on the Moon.