(meteorobs) Observation December 12/13 2007

[meteoreye at comcast.net]

Pierre,
There is another radiant I hadn't mentioned much.
It's from Sirko Molau's summary of IMO video observations, shower number 78 on his list.
It is from the Northern Toroidal radiant which is active a few times during the year.
The toroidal meteors are those in highly inclined (hence very stable orbits) that have been regarded as concentrations in the Sporadic Background (See Density Distribution Figure 4-5 in IMO Handbook for Visual Meteor Observers). Sirko's analysis indicated 5 intervals during the year when the activity from ths source rose to the detectable threshold.
This one is active from the 6th to the 23rd, with a peak on the 20th.
It's a very low rate shower but met his detection threshold
The radiant on that night would have been halfway between the end of the 
handle of the big dipper (eta UMA),
and Draco's tail (iota DRA)  at RA 218 (14:33), Dec +58
Velocity is 44 km/sec.
With all the other activity further to the south and southeast I don't generally face that direction.

Peak night (Dec 20) radiant is 209 (13:57) +56.

Based on that radiant, until a better name comes along, I will call them the DUMs :->
(December Ursa Majorids)

This shower would be expected to be at the limit of visual detectability, ~ 2-3/Hr.
That's why I did not cover it in the NAMN notes, it's so far down the list I couldn't fit it in.

There is no IAU shower listed that corresponds to that radiant, and I have not completed a search among all other sources, but have found no named shower so far.

If you get another chance to observe, let me know (off meteorobs) and I'll send you the daily radiant positions.

It would be great to plot such meteors, but I find that plotting is very difficult when dressed in arctic gear. And I'm a lightweight, I will be dressed that way for a mere -10C if it should clear for a bit this morning.

Wayne



-------------- Original message -------------- 
From: Pierre Martin <dob14.5 at sympatico.ca> 

> Hello all, 
> 
> Here's my report for the pre-max Geminids night. 
> 
> I had the pleasure to have the company of Raymond Dubois. This was a 
> very cold night at -23C (-9.4F). This session required careful 
> planing ahead of time, to ensure that I'd be able to handle the 
> cold. There was a new accessory that I tried for the first time that 
> was quite helpful - a propane catalytic heater. The stream of heat 
> emitted from it was mild but enough to take the edge off the cold. I 
> also had a new heavy parka, several hand warmers and my down-filled 
> sleeping bag. While Raymond and I were packing up the van, it looked 
> like we were heading for a week-long polar expedition :) 
> 
> By 11pm, we left Ottawa and drove over an hour to the south-west of 
> Ottawa... looking for a quiet country road that had a good horizon 
> and minimal local lights. As we drove, we even spotted a few 
> meteors. We found such a spot (Weedmark road) about 15km south of 
> the town of Merrickville, so we stopped and setup on the side of that 
> road. The sky overhead was quite impressive, with about 4/5 
> transparency and limiting magnitude over 6.5. The winter Milky Way 
> was faintly visible among a myriad of stars, and Comet Holmes is 
> looking so large to the unaided eyes that it could probably be 
> mistaken for a small cloud by someone unaware of its nature. 
> 
> I took my time to setup my equatorial mount and my two cameras with 
> wide-angle lenses. Raymond also had his mount to run his camera. 
> (Setting up with gloves also slows down the process). Within an 
> hour, everything was ready to go! So I programmed the cameras to do 
> a series of exposures for the rest of the session - and then seeked 
> my warm sleeping bag. 
> 
> I observed meteors formally for two hours between 2:10am - 5:00am 
> EST. The Geminids rates were decent considering that the peak was 
> over 33 hours away at that point (not counting minor showers and 
> sporadics, 26 Geminids were seen the first hour, and 35 for the 
> second). Geminids were on average very faint meteors, with many in 
> the mag +4 to +5 range (even a few +6!). The brightest Geminid was a 
> mag -1 meteor, but it was far from my field of view and not well seen. 
> 
> The highlight was actually not a Geminid but a very well seen 
> antihelion that had a graceful, slow path that reached mag -1. It 
> was almost pure white and left a delicate wake along its path. 
> Beautiful! 
> 
> I took note of 4 swift meteors that seemed to radiate from Ursa 
> Major. I have been noticing these meteors almost every year around 
> the Geminids maximum. Unfortunately, it's so difficult to plot when 
> the weather is that cold, and when meteor rates are high enough to 
> make this impractical. At 5am, Raymond and I very carefully packed 
> all our gear. Camera wires had become very stiff due to the cold. 
> There was also a small layer of frost. Needless to say, it was quite 
> brutally frigid, but enjoyable! 
> 
> Last night's Geminids peak was a full washout. I'm however expecting 
> clear skies for the post-max night! 
> 
> Pierre Martin 
> Ottawa, Ontario 
> 
> P.S. I had a quick look at my photos, and at least no real bright 
> meteors were captured by the cameras - I'll have a closer look for 
> the fainter ones. Raymond was telling that he captured one Geminid! 
> 
> 
> DATE: December 12/13 2007 
> BEGIN: 0710 UT (0210 EST) END: 1000 UT (0500 EST) 
> OBSERVER: Pierre Martin (MARPI) 
> LOCATION: Long: -75 49' West; Lat: 44 55' North 
> City & Province: Merrickville, Ontario, CANADA 
> RECORDING METHOD: pencil and paper method, cord align 
> ---------------------------------------------------------- 
> 
> OBSERVED SHOWERS:______________________________radiant position 
> MON (Monocerotids)_____________________________06:36 (099) +08 
> GEM (Geminids)_________________________________07:08 (107) +33 
> HYD (Sigma Hydrids)____________________________08:20 (125) +02 
> COM (Coma Berenicids)__________________________11:16 (169) +27 
> ANT (antihelions)______________________________05:56 (089) +23 
> SPO (sporadics) 
> ---------------------------------------------------------- 
> 
> OBSERVING PERIODS: 0 = none seen; / = shower not observed 
> 
> PERIOD(UT)___FIELD____Teff____F______LM____SPO_GEM_MON_HYD_COM_ANT 
> 
> 0710-0810___0625+14___0.98___1.00___6.53___10__26___2___2___0___1 
> 0839-1000___0821+15___1.13___1.00___6.53____9__35___1___0___2___1 
> 
> TOTALS:_______________2.11_________________19__61___3___2___2___2 = 89 
> 
> Note: The first column (Period UT) refers to observing periods broken 
> down as close as possible to one hour of true observing, in Universal 
> Time. The second column (Field) is the area in in the sky where I 
> centered my field of view. The third column (TEFF) represents 
> effective observing time (corrected for breaks or any time not spent 
> looking at the sky). The column (LM) is the average naked eye 
> limiting magnitude, determined by triangle star counts. All following 
> columns indicate the number of meteors for each shower observed. 
> ------------------------ 
> 
> MAGNITUDE DISTRIBUTIONS: 
> 
> SHOWER 
> ______-1___0__+1__+2__+3__+4__+5__+6______AVE 
> 
> GEM____1___1___5___9__18__14___9___4_____+3.30 
> SPO____0___0___2___2___5___5___5___0_____+3.47 
> MON____0___0___0___1___1___1___0___0_____+3.00 
> HYD____0___0___0___1___0___0___1___0_____+3.50 
> COM____0___0___1___1___0___0___0___0_____+1.50 
> ANT____1___0___0___0___0___1___0___0_____+1.50 
> 
> Note: Magnitude -8 is comparable to a quarter moon, magnitude -4 with 
> the planet Venus, magnitude -1 with the brightest star Sirius, 
> magnitude +2 to +3 with most average naked eye stars and magnitude +6 
> to +7 are the faintest stars the naked eye can see under typical dark 
> conditions. A meteor of at least magnitude -3 is considered a 
> fireball. The above table contains the magnitudes from all observed 
> meteors, and the average (last column) for showers. 
> ------------------------ 
> 
> SKY OBSCURED (FOV) (UT): none 
> 
> ------------------------ 
> 
> Dead time: 14 min (breaks) 
> 
> Breaks (UT): 7:16 (30sec), 7:58 (30sec), 8:10-39, 9:20-32 
> 
> 
> 
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