Meteorscatter
PREVIEW of 144 MHz-Activities for the upcomming METEOR-Showers

UPCOMING METEOR SHOWERS: DECEMBER 2014

December is, as usual, characterized by the return of one of the most active (and probably the most reliable) major annual showers: the Geminids.
Geminids maximum is expected to occur on December 14th, 12h UT, with ZHR = 120 hr-1 at peak. Since the peak has shown slight signs of variability in its rates and timing in recent years, please note that the more reliably-observed maxima during the past two decades have all occurred within the range λsol = 261°5 and 262°4, equivalent to 2014 December 13th, 19h UT to December 14th, 17h UT. Near-peak rates usually persist for almost a day, while fainter meteors should be most abundant almost a day ahead of the visual maximum. Note that theoretical modelling by Jeremie Vaubaillon indicates the greatest dust particle density could be encountered during the UT daylight hours of December 15th this year. The Geminids peak is typically quite broad (thus ensuring a several-days-long period of good MS activity), although the rates sometimes decay fairly quickly after the maximum.

Regarding minor showers, Southern Emisphere observers will carefully monitor Phoenicids (peaking Dec. 6th) and Puppids/Velids (peaking Dec. 7th), while in the Northern Emisphere the most interesting among December’s minor showers is Ursids. Ursids produced two major outbursts in the past 70 years (in 1945 and 1986) and several other rate enhancements (1988, 1994, 2000, 2006, 2007 and 2008), the latter probably influenced by the relative proximity of the shower’s parent comet, 8P/Tuttle, at perihelion in January 2008. Stream modelling by Jeremie Vaubaillon indicates a possible encounter with the 1392 AD dust trail this year, that could produce activity around 00h 40m UT on December 23, although the age of this dust trail means the potential ZHRs are highly uncertain. The “normal” Ursids peak is expected to occur on December 22nd, 20h UT.



For Radio Observers, the (Theoretical) UT peaks for upcoming showers in December 2014 are as follows:


Phoenicids (Southern Emisphere shower)
Active: November 28 – December 09
Maximum: December 06, (λsol= 254°25)
ZHR: Variable – typically low, but may reach 100 hr-1 or more

Puppids / Velids (Southern Emisphere shower)
Active: December 01 – December 15
Maximum: December 07 (λsol= 255°)
ZHR: Low (10 hr-1)

Monocerotids
Active: November 27 – December 17
Maximum: December 09 (λsol= 257°)
ZHR: Low (2 hr-1)

σ- Hydrids
Active: December 03 – December 15
Maximum: December 12 (λsol= 260°)
ZHR: Low (3 hr-1)

Geminids
Active: December 04 – December 17
Maximum: December 14, 12h UT (λsol= 262°2)
ZHR: High (120 hr-1)

Comae Berenicids
Active: December 12 – December 23
Maximum: December 16 (λsol= 264°)
ZHR: Low (3 hr-1)

December Leonis Minorids
Active: December 05 – February 04
Maximum: December 20 (λsol= 268°)
ZHR: Low (5 hr-1)

Ursids
Active: December 17 – December 26
Maximum: December 22, 20h UT (λsol= 270°7)
ZHR: Low (10 hr-1)

(Source: IMO)



SOME TIPS ABOUT GEMINIDS

The Geminids Radiant is circumpolar (that means, is above horizon the entire day) for every observer northern of about 57°N latitude during shower activity. At southern latitude in Europe, the radiant will set in the late morning and rise in the early evening.

For a Central Europe observer (say, in JN59 square and surroundings) the radiant is below horizon from about 10:30 UT till about 16 UT. Radiant elevation is relatively low above horizon in late morning (08:30-10:30 UT) and late afternoon (16-18:30 UT). Radiant culminates around 01 UT and remains rather high above horizon in late night (00-03 UT). Optimal height of radiant above horizon for best radio efficiency can be found between 20 UT and 23 UT, and between 04 UT and 07 UT.

For the Central Europe observer mentioned above, the relative radiant position tends to favor especially the radio paths in N/S direction, in the morning and early night hours. Best geometric efficiency direction Vs. Time around Geminids maximum can thus be summarized as follows:

Direction of radio path vs. Time for best efficiency (UT)

N/S: 04 – 06 and 20 – 22

NE/SW: 05 – 08 and 21 – 00

E/W: 01 - 02

NW/SE: 03 – 05 and 19 – 22


This calculation is valid for the center Europe observer as mentioned. Moving significantly away from that area will somewhat change the times for best efficiency, so this table should be used only for an approximate evaluation (although somehow valid for most Europe). Check your actual directions for best efficiency Vs. Time for your area, using tools like Virgo, OH5IY soft and so on. Please note that the above calculated efficiency applies better on Underdense trails ( that produce Pings), while Overdense trails ( that produce longer Bursts) are somewhat less dependent by geometry (radiant position with respect to direction of radio path).




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MMMonVHF MS Activity OVERVIEW (PAST SHOWERS)

As for past MS-Showers, the VHF-DX-Portal MMMonVHF will produce an up to date MS OVERVIEW concerning the next major Meteor Shower.


MMMonVHF since 2008, is archiving the ACTIVITY-OVERVIEWS related to the past major MS-Shower:

MS-SPRINT & PERSEIDS 2008:
OVERVIEW PDF-File & SQUARE-MAP

BCC & GEMINIDS 2008:
OVERVIEW PDF-File & SQUARE-MAP

MS-SPRINT & PERSEIDS 2009:
OVERVIEW PDF-File & SQUARE-MAP

BCC & GEMINIDS 2009:
OVERVIEW PDF-File & SQUARE-MAP

MS-SPRINT & PERSEIDS 2010:
OVERVIEW PDF-File & SQUARE-MAP

BCC & GEMINIDS 2010:
OVERVIEW PDF-File & SQUARE-MAP

MS-SPRINT & PERSEIDS 2011:
OVERVIEW PDF-File & SQUARE-MAP

BCC & GEMINIDS 2011:
OVERVIEW PDF-File & SQUARE-MAP




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