The International Meteor Organization (IMO) was founded in 1988 and has more than 250 members now. IMO was created in response to an ever growing need for international cooperation of meteor amateur work. The collection of meteor observations by several methods from all around the world ensures the comprehensive study of meteor showers and their relation to comets and interplanetary dust.
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Never mind the new year fireworks, the start of 2015 happened with an even bigger bang, at least if you happened to be in Romania, Moldova or the Ukraine. The early hours of January 7th saw a massive fireball over the region, culminating in an explosion loud enough to wake people, and causing many to call the emergency services to report the event. In Romania reports of sightings have come in from across the country, putting the time of the explosion at 3:05 EET (01:05 UT), with people hearing the explosion in the counties of Buzau, Vrancea and Covasna.
So far over 50 recordings and eye witness reports have been collected by the IMO, many from surveillance cameras recording sudden brightening of whatever outside area was being monitored. A compilation of videos of the event, as recorded by security cameras, has been posted on youtube. The map below shows the location of the reports received so far, red dots are from surveillance cameras, the blue markers are visual reports from witnesses, and the green dots are reports from those who heard the terminal explosion.
Image by Raul Truta, compiled from online reports.
Red: detections by cameras, blue: visual observations, green: reports of sound heard.
The reports from Romania of the January 7th fireball put the maximum apparent magnitude of -16, brighter than the full Moon (-13). Roughly one in 1,200 meteors is brighter than magnitude -5, while only one on 12,000 meteors reaches magnitude -8 or brighter, so fireball events like this one are rare.
So far, information on the event is sparse. The explosion appears to have occurred at a height of roughly 55 kilometres and, although some fireballs do result in meteorite fragments reaching the ground, it is likely that in this case the meteoroid completely disintegrated.
Whether a fall occurs or not, the details of events like this can only be determined from combining the information from many eyewitness reports. If you see a bright fireball event like this, you can help researchers by reporting what you saw in as much detail as possible. You can find further information on meteors and other related events, and advice on how to observe and report them, visit the observations section of the IMO website.
The December 2014 issue of the IMO Journal is now in print. It will be mailed shortly and subscribers can also immediately access the journal in PDF format. The contents this month:
Front cover photo: Bright fireball on 2014 February 24 at 01h45m UT from Milton, VT, USA. Photo courtesy: Ethan Rogati.
The nights between December 9 and 16 are marked by the best of all meteor showers – the Geminids. Up to 120 meteors per hour are visible during the shower’s peak on December 14 under dark skies, far from light pollution. This meteor shower, rich in bright, colorful meteors is also characterized by an unusually long period of relatively high activity – if you cannot observe on the peak night, you can see good numbers of meteors on December 12, 13 and 15! This year the peak of the Geminid meteor shower is expected on December 14 around 12h UT, but near-maximum rates persist for about a day, so everyone will have a good chance to see great meteor rates.
The activity graph below is updated every 15 minutes - click for details.
But the Geminids are not remarkable only due to their strength, they are also somewhat unusual as meteor showers go. While most meteor showers are born from comets, the Geminids appear to be bits of an asteroid. The parent body of the meteor shower is asteroid 3200 Phaethon. This 5-km rocky body orbits the Sun in an elongated elliptical orbit, which carries it out to the main asteroid belt at aphelion and as close to the Sun as 0.14 astronomical units at perihelion (more than twice as close to the Sun than Mercury!). 3200 Phaethon is a B-type asteroid, but recent observations with the STEREO spacecraft have revealed cometary activity near perihelion, so it is also referred to as a “rock comet”. It is hypothesized that the dust release is caused by thermal fracturing of the surface of the comet under intense heating near the Sun. 3200 Phaethon is a very interesting body and will certainly be the target of much future research!
To observe the Geminid shower at its best, try to find an observing spot far from city lights. Light pollution will greatly diminish the number of visible meteors. You need no specialized equipment to observe the Geminids! Dress warmly, bring a reclining chair and watch the sky. You will not need to wait long for the first Geminid to appear!
The Geminid radiant is located in the constellation of Gemini, near the bright stars Castor and Pollux. On the peak night the radiant is just about a degree north of Castor (the northern twin). All Geminids will appear to radiate from this point in the sky. With 35 km/s the Geminids are medium speed meteors.
On the peak night the waning gibbous Moon rises around local midnight, so the evening hours will be dark. For mid-northern latitudes the radiant rises at dusk, so some Geminids may be seen even during the early evening hours. And these Geminids are special! As the radiant is very low, meteoroids skim the upper layers of the atmosphere nearly tangentially, creating long meteors that can traverse half of the sky or more! These meteors are called Earth grazers. As the radiant rises higher in the sky, the number of meteors increases. But even in the morning hours, as the Moon rises higher in the sky, still many Geminids will be visible, right up until dawn.
If you decide to do observe the Geminids, use the IMO major meteor shower observing technique. This way your data will be in a standard format, that can readily be used for analysis. Send us your data as soon after the observations as possible.
If you are new to meteor photography, this shower will be somewhat more difficult due to the bright Moon. But photographing meteors is fun, and it is easy. You will need a good camera – a DSLR, a mirrorless cam or a good bridge camera will do, a tripod and a remote release. Set the aperture to a wide setting, depending on the lens you have this is usually anywhere between f/1.4 and f/3.5. Set the camera to Manual mode (M) or Bulb (B), depending on what your camera offers. You would usually go for a relatively high ISO value, but since the sky will be bright you can stay at about ISO 800 or so. Now focus the image. Focusing your camera is absolutely crucial! There are few things as frustrating as out of focus photos! Use live view to focus on a star manually. Shift the focus around until the image of the star on your screen reaches minimum size. You can also use autofocus on the Moon, but do check your first photo if it is really in focus. Then set your exposure to about 10 – 15 seconds and use the remote release to make the photo (if you do it on your camera shutter button your photos will be blurred due to camera motion). Then find the exposure you are most comfortable with – this will depend on how bright you allow the photos to be (do not go too far or any meteors will be drowned out in the bright background) and how bright your sky is.
The October 2014 issue of the IMO Journal is now in print. It will be mailed shortly and subscribers can also immediately access the journal in PDF format. The contents this month:
Front cover photo: Bright meteor on 2014 May 29 at 03h33m UT from Observatorio del Teide, Tenerife, Spain. Photo courtesy: Jürgen Rendtel.
The August 2014 issue of the IMO Journal is now in print. It will be mailed shortly and subscribers can also immediately access the journal in PDF format. The contents this month:
Front cover photo: Very bright fireball on 2013 September 28 at 03h33m UT from Ohio, USA. Photo courtesy: Angela McClain.