Dzisiaj jest 11 grudnia 2019, 05:04

Czas środkowoeuropejski letni




Nowy temat Odpowiedz w temacie  [ Posty: 1 ] 
Autor Wiadomość
Post: 02 lutego 2019, 19:09 
Offline
Użytkownik
Awatar użytkownika

Rejestracja: 20 maja 2014, 18:55
Posty: 352
February offers the meteor observer in the northern hemisphere a couple of weak showers plus falling sporadic rates. This may not seem too exiting but you never know when surprises are in store. An errant earthgrazer from the Centaurid complex may shoot northward. Better yet, a bright fireball may light up the sky. February is the start of the evening fireball season, when an abundance of fireballs seem to occur. This lasts well into April as seen from the northern hemisphere. Sporadic rates are near maximum for those viewing from the Southern hemisphere. There are no strong showers this month but sporadic rates are well in excess of 10 per hour as seen from mid-southern latitudes.

During this period the moon will reach its new phase on Monday February 4th. At this time the moon will be located near the sun and will be invisible at night. As the week progresses the waxing crescent moon will enter the evening sky. It will be so thin and will set early that it will not interfere with the viewing of meteor activity during this period. Hourly meteor rates for evening observers this week is near 3 as seen from mid-northern latitudes (45N) and 4 as seen from tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 12 as seen from mid-northern latitudes and 13 from the southern tropics. 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. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning February 2/3. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.
These sources of meteoric activity are expected to be active this week.

The center of the large Anthelion (ANT) radiant is currently located at 09:48 (147) +13. This position lies in western Leo, 4 degrees northwest of the 1st magnitude star known as Regulus (alpha Leonis). Due to the large size of this radiant, Anthelion activity may also appear from Cancer, northwestern Hydra, and Sextans as well as Leo. This radiant is best placed near 0100 local standard time (LST), when it lies on the meridian and is located highest in the sky. Rates at this time should be near 2 per hour as seen from the northern hemisphere and 1 per hour from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The alpha Antliids (AAN) should be active from a radiant located near 10:36 (159) -10. This position actually lies in southern Sextans, 4 degrees northeast of the 4th magnitude star known as lambda Hydrae. I'm not certain how this stream was named as it the radiant lies a good 20 degrees north of the Antlia border. Perhaps when activity was first noticed from this source the radiant was incorrectly determined? This radiant is best placed near 0200 LST, when it lies on the meridian and is located highest in the sky. Rates are expected to be near 1 per hour no matter your location. With an entry velocity of 45 km/sec., the average meteor from this source would be of medium velocity.

The February Epsilon Virginids (FEV) were discovered by Kathryn Steakly & Dr. Peter Jenniskens using data from CAMS and SonotaCo. This shower is active from January 29-February 9, with maximum activity occurring on February 3rd. The radiant is currently located at 13:22 (200) +11, which places it in northern Virgo, 3 degrees east of the 3rd magnitude star known as Vindemiatrix (Epsilon Virginis). These meteors would be best seen near 0400 LST when the radiant lies highest above the horizon. Rates are expected to be near 1 per hour during the last dark hour before dawn. These meteors are equally well seen from either hemisphere. These meteors encounter the atmosphere at 64 km/sec., which would produce mostly swift meteors.

The alpha Centaurids (ACE) are active from February 2-19, with maximum activity occurring on February 8. The radiant is currently located at 13:38 (205) -57. This position lies in southeastern Centaurus, 2 degrees south of the 2nd magnitude star known as epsilon Centauri. Due to the southern declination of this radiant, these meteors are not well seen in the northern hemisphere. Current rates are expected to be near 1 for those in the southern hemisphere and less than 1 for those located north of the equator. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. At 56 km/sec. the alpha Centaurids would produce mostly swift meteors.

The pi Hydrids (PIH) were discovered in Dr. Peter Jenniskens and mentioned in his book Meteor Showers and their Parent Comets. Studies of the IMO video database by Sirko Molau and Juergen Rendtel confirmed the existence of this shower. These meteors are active from February 4-15, which maximum activity occurring on the 6th. At maximum the radiant is located at 14:00 (210) -21. This area of the sky is located in extreme southeastern Virgo, 6 degrees northwest of the 3rd magnitude star known as Pi Hydrae. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. Rates are expected to remain below 1, even at maximum activity. These meteors are visible over most of the Earth, with the southern hemisphere having slightly better viewing conditions. At 55 km/sec. the Pi Hydrids would produce mostly swift meteors.

The February Eta Draconids (FED) were discovered by Dr. Peter Jenniskens and Peter Gural using data from the first CAMS network in northern California. These meteors are active on only 3 nights, February 3-5. The maximum occurs on February 4 when the radiant is located at 15:59 (240) +61. This position lies in central Draco, 3 degrees west of the 3rd magnitude star known as Eta Draconis. These meteors are best seen during the last dark hour before dawn when the radiant lies highest above the horizon in a dark sky. Expected rates would be less than 1 per hour, even at maximum. These meteors are difficult to see from the southern tropics and impossible to see from latitudes south of 30S. At 35 km/sec. the February Eta Draconids produce mostly medium-slow meteors.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 7 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would also be near 10 per hour as seen from rural observing sites and 3 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.
SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Standard Time North-South
Anthelion (ANT) - 09:48 (147) +13 30 01:00 2 - 1 II
alpha Antliids (AAN) Feb 01 10:36 (159) -10 45 02:00 1 - 1 IV
February Epsilon Virginids (FEV) Feb 03 13:22 (200) +11 64 04:00 1 - 1 IV
alpha Centaurids (ACE) Feb 08 13:38 (205) -57 59 04:00 1 - <1 II
pi Hydrids (PIH) Feb 06 14:00 (210) -21 55 05:00 <1 - <1 IV
February eta Draconids (FED ) Feb 04 15:59 (240) +61 35 07:00 <1 - <1
Zgodnie z:
Robert Lunsford


Na górę
 Wyświetl profil  
 
Wyświetl posty nie starsze niż:  Sortuj wg  
Nowy temat Odpowiedz w temacie  [ Posty: 1 ] 

Czas środkowoeuropejski letni


Kto jest online

Użytkownicy przeglądający to forum: Obecnie na forum nie ma żadnego zarejestrowanego użytkownika i 3 gości


Nie możesz tworzyć nowych tematów
Nie możesz odpowiadać w tematach
Nie możesz zmieniać swoich postów
Nie możesz usuwać swoich postów
Nie możesz dodawać załączników

Szukaj:
Przejdź do:  
cron
Technologię dostarcza phpBB® Forum Software © phpBB Group