The Zenithal Hourly Rate is the valutation of the hourly number
of meteors that teorically an observer can see in one hour under a sky with magnitude
6.5 and with the radiant at zenith.
It is based on the formula of NAMN (North American Meteor Network)
if LM is greater than 6.5 if LM is lower than 6.5
(HR) (r)^1-(LM - 6.5) (HR) (r)^(6.5 - LM)
ZHR = ----------------------- ZHR = -----------------------
sin (A) sin (A) |
The index of popolation (r) |
The index of popolation (r) defines the brightness of the meteors of a shower
Shower |
Activity Period |
r |
Antihelion Source (ANT) |
Nov 26 - Sep 24 |
3.0 |
Quadrantids (QUA) |
Jan 01 - Jan 05 |
2.1 |
alpha-Centaurids (ACE) |
Jan 28 - Feb 21 |
2.0 |
delta-Leonids (DLE) |
Feb 15 - Mar 10 |
3.0 |
gamma-Normids (GNO) |
Feb 25 - Mar 22 |
2.4 |
Lyrids (LYR) |
Apr 16 - Apr 25 |
2.1 |
pi-Pupiids (PPU) |
Apr 15 - Apr 28 |
2.0 |
eta-Aquarids (ETA) |
Apr 19 - May 28 |
2.4 |
eta-Lyrids (ELY) |
May 03 - May 12 |
3.0 |
June Bootids (JBO) |
Jun 22 - Jul 02 |
2.2 |
Piscis Austrinids (PAU) |
Jul 15 - Aug 10 |
3.2 |
South. d-Aquarids (SDA) |
Jul 12 - Aug 19 |
3.2 |
alpha-Capricornids (CAP) |
Jul 03 - Aug 15 |
2.5 |
Perseids (PER) |
Jul 17 - Aug 24 |
2.6 |
kappa-Cygnids (KCG) |
Aug 03 - Aug 25 |
3.0 |
alpha-Aurigids (AUR) |
Aug 25 - Sep 08 |
2.6 |
September Perseids (SPE) |
Sep 05 - Sep 17 |
2.9 |
delta-Aurigids (DAU) |
Sep 18 - Oct 10 |
2.9 |
Draconids (GIA) |
Oct 06 - Oct 10 |
2.6 |
epsilon-Geminids (EGE) |
Oct 14 - Oct 27 |
3.0 |
Orionids (ORI) |
Oct 02 - Nov 07 |
2.5 |
Leo Minorids (LMI) |
Oct 19 - Oct 27 |
3.0 |
Southern Taurids (STA) |
Sep 25 - Nov 25 |
2.3 |
Northern Taurids (NTA) |
Sep 25 - Nov 25 |
2.3 |
Leonids (LEO) |
Nov 10 - Nov 23 |
2.5 |
alpha-Monocerotids (AMO) |
Nov 15 - Nov 25 |
2.4 |
Dec Phoenicids (PHO) |
Nov 28 - Dec 09 |
2.8 |
Puppid/Velids (PUP) |
Dec 01 - Dec 15 |
2.9 |
Monocerotids (MON) |
Nov 27 - Dec 17 |
3.0 |
sigma-Hydrids (HYD) |
Dec 03 - Dec 15 |
3.0 |
Geminids (GEM) |
Dec 07 - Dec 17 |
2.6 |
Coma Berenicids (COM) |
Dec 12 - Jan 23 |
3.0 |
Ursids (URS) |
Dec 17 - Dec 26 |
3.0 |
Source : IMO |
