Essential items to record and report:
1) Exactly where you were (give the name of the nearest town or village, and county if in Britain, or your geographic latitude and longitude if elsewhere in the world, as well as the place and country name);
2) The date and timing of the event (please be sure to state clearly whether this was in Universal Time, UT, which is the same as Greenwich Mean Time, or in local clock time - remember British Summer Time starts on the last weekend of March); and
3) Where the fireball started and ended in the sky, as accurately as possible, or where the first and last points you could see of the trail were if you did not see the whole flight.
In order to reconstruct accurately what you saw, to compare it with other witness-reports and attempt to triangulate to its atmospheric trajectory, it is VITAL you describe where the meteor was in the sky as clearly as you can.
At night, with plenty of stars visible, if you're familiar with the astronomical convention of using Right Ascension, RA, and Declination, Dec, to describe sky-positions, give these points in RA and Dec.
If the fireball was seen in daylight, or twilight too strong to see sufficient stars, or if you are not familiar with estimating RA and Dec positions, please use altazimuth positions instead.
Any point in the sky can be determined by two quantities, its ALTitude or elevation in degrees measured vertically up from the horizontal, and its AZIMUTH, literally "directions", in degrees measured around the sky parallel to the horizontal.
Altitude starts at 00° (horizontal) and runs up to 90° (the zenith, or overhead point). Azimuth is measured from true north eastwards (that is, clockwise), thus 000° is due north, 090° is due east, 180° is due south, 270° is due west, and so forth. It is useful to give altitude values as two-digit numbers, and azimuth ones as three-digits to help avoid confusion.
To help make angular measures, the distance across your clenched knuckles of the hand held at arm's length from your eye gives an angle of about 10°. The distance between the outer edges of your thumb and fourth finger of an outspread hand, again held at arm's length, forms an angle of about 22°. A single fingertip at arm's length makes an angle of about 1°.
Other items to report (in decreasing order of importance):
* Apparent speed: If you are a regular meteor observer, use the normal 0 to 5 meteor-speed scale (0 = stationary, that is heading directly towards you through the atmosphere, 1 = very slow, 2 = slow, 3 = medium speed, 4 = fast and 5 = very fast).
If you are less familiar with meteors, estimate instead how long the fireball was visible in partial or complete seconds. Very few fireballs last more than 10 seconds, and only rare man-made re-entry fireballs are likely to last between several tens of seconds to a couple of minutes. If the object was visible for longer than these times, it may not have been a fireball (see the section "Fireball or not?" at the end of this posting).
* Persistent train: Some meteors may leave a glowing ionization train along their trajectory after they have disappeared. If so, estimate how long this took to fade from view in seconds.
* Sounds: Rarely, noises may happen from brighter fireballs. These may be simultaneous with the meteor's flight, typically described as hissing, whooshing or crackling, also called electrophonic sounds. It is important to rule out any terrestrial noises that happened by-chance at the same time as the meteor appeared. More common, but still very rare, are noises heard tens of seconds to a few minutes after the fireball has ended, usually rumblings or bangs, due to acoustic shock waves or "sonic booms". Again, terrestrial causes need to be ruled out where possible. Note what you heard, and the approximate delay between seeing the meteor and hearing the sounds.
* Fragmentation: Give details. May include a breakup into smaller meteors, or sparkling seen along the track while the object was in flight.
* Colours: Use only pure hues, that is: red, orange, yellow, green, blue, violet, white.
* Magnitude: Try to estimate how bright the event was, giving a range if in doubt. This is often very difficult to do precisely, so is the least important item to note. To help: Jupiter at its brightest is magnitude -2.9; Venus at its brightest is magnitude -4.8; the 4 or 24 day old crescent Moon is about magnitude -8; first or last quarter Moon is around magnitude -10; the 11 or 18 day gibbous Moon is roughly magnitude -11/-12; full Moon is magnitude -13; the Sun is magnitude -26. (Technically a fireball is any meteor -3 magnitude or brighter)
Fireball or not?
Not all very bright moving lights in the sky are fireballs. In all cases, viewing these objects with firmly-held and focused binoculars should allow a rapid identification. If the object streaked away and vanished before you could lift the binoculars to your eyes, it may well have been a meteor after all!
* Sky-lanterns: Roughly metre-high, paper hot air balloons, each powered by a burning wick suspended below it. Very commonly mistaken for meteors by novice witnesses. Frequently seen over Britain near public holidays, less frequently at other times of year. Can look like literal "balls of fire", but are much slower-moving and longer-lasting than meteors (lanterns typically remain visible between tens of seconds to several minutes). Colours commonly reported are yellow, orange or red, though others are known, including black (shadow effects, or printing on the balloon). Genuine fireballs never show black, only brilliant, radiant light. Lanterns may be clearly burning or flickering, occasionally dropping flaming or glowing material vertically below them, and can seem surprisingly bright for their size, because their wicks burn like miniature chip-pan fires, sometimes magnified by reflection in the balloon-bag.
* Aircraft lights: These are not always obvious. Look out for repeat flashes nearby soon afterwards (landing lights) and a motion slower than most natural meteors.
* Satellite flares: Flashes of light from artificial satellites in Earth-orbit, catching the Sun briefly. The Iridium communication satellites and some others with large solar panels can be especially brilliant. All man-made objects orbiting the Earth have apparent speeds far below those of even the slowest natural meteors, but some short-lived flares can be difficult to tell apart from a genuine fireball's flare. If you record what you saw as usual, noting the exact time, and the flare's altitude and azimuth, you can then check the Heavens Above website, http://www.Heavens-Above.com , to see if any of the events there coincided with what you observed.
A good link for apparent magnitude for comparison is here. http://en.wikipedia....arent_magnitude
It is also worth mentioning any constellations the fireball starts and finishes in.
Don't worry if you can't get all the information its still worth posting a report as it may match up with others.
Post your sighting in its own thread with the heading Fireball Date and location in the Space weather forum.
Bear in mind a number of objects can be mistaken as fireballs ie Flares, Aircraft, Chinese lanterns so try to rule these out prior to a report.
Example of Chinese Lanterns. http://www.youtube.c...feature=related
Example of Iridium Flare. http://www.youtube.c...h?v=1PFUP5LPyuA
Example of Parachute Flare. http://www.youtube.c...h?v=YBGsDlqTF0Q
You can also forward your report to the SPA here http://www.popastro....tform/index.php
Posted 07 December 2011 - 20:49
Posted 13 December 2011 - 19:32
Now if someone had it on tape and played it back to I would have said it was a large firework rocket taking off with the image having been rotated.
Time was 6.18pm give or take a min.
I am no expert so please forgive my poor description but over the years I have seen various large Fireballs in all shapes, speeds and colours even smoke trails however this really was unlike anything I have seen! Quite a sight tbh and one had I been with others would have more than enough time to say look quick!
This post has been edited by Alex R: 13 December 2011 - 19:33
Posted 03 January 2012 - 20:54
That's about all I can say....