Author: admin

The best and most reliable meteor shower of the year are the Geminids at 120 meteors per hour on early Monday December 14. The second best are the Quadrantids at 120/hr on January 4 but these last only for a few hours. The Perseids are better known, since they occur on August 13 when it’s nice and warm out. But they’re actually number three on the list at 100 meteors per hour.

Since the new Moon occurs on Dec 11, the sky will be dark so we should see even the fainter meteors. The peak should occur around 10am in the morning, Dec 14, persisting for 24 hours. But 2am is fine when the shower’s radiant point, Gemini, rises high in the sky to the East. The meteors are the sand, dust and gravel remains of an Apollo asteroid (3200 Phaethon), coming in at medium speeds of 35km/second. (That’s a medium speed for a meteor. Other meteor shower velocities range from 11 to 72 km/s.) The Geminids come in various colours–65% being white, 26% yellow, and the remaining 9% blue, red and green. They’re active from Dec 4 until Thursday Dec 17. Last night I saw a bright yellow tinted fireball zip across Orion crossing a quarter of the Southern sky, leaving a shorter glowing trail along the last third of it’s flight; and another fireball went across Taurus just two minutes later. Last night I saw a bright yellow tinted fireball zip across Orion crossing a quarter of the Southern sky, leaving a shorter glowing trail along the last third of it’s flight; and another fireball went across Taurus just two minutes later.

Which direction is best to look? Where it’s darkest. As you can see in these composite photos from last year, the fireballs scatter all over the sky, radiating out from Gemini to the East. But when you watch the area around Gemini, the streaks there are shorter and slower moving. These fisheye photos show the whole sky as a circle: North is up, South down, East to the left, and West to right.

These photos were taken from Cranbrook, BC with the College of the Rockies meteor cam.

Below is a starmap looking East around 11pm on Dec 14. Note Gemini the Twins rising due East, just left of Orion the Hunter. Look for two bright stars, Castor over top of the other, Pollux. Gemini the Twins used to be a benevolent guide for the ancient Sailers. In movies you sometimes hear old sailors exclaim “By Jiminy!”. Sirius is the very bright star along the SouthEastern horizon below Orion. Taurus the Bull is the “>” shape above Orion, with the red eye of Aldebaran. The Pleiades are a small fuzzy patch above that.

These pictures are pixelated to fit in this small window–right click and open image in a new tab to zoom in more.

The smoke and haze in Southeastern BC was a problem, but the Allsky Meteor Cam on the Cranbrook College of the Rockies roof still got a dozen bright Perseids or so on the 12-13th. Not 52 like Jeff Brower got on his AllSky meteor cam in Kelowna, by a long shot. This year was a bit better than 2013, although not as many bright fireballs. Below are the brightest ten meteors of the night, all shown on one frame, on the fisheye all-sky view.

I ended up going to the top of nearby Mt. Baker to get above the smoke. South of Cranbrook, just 26km on my tripmeter on a gravel logging road with lots of switchbacks, ending at some radio towers at 7,200 ft altitude. Even up there the horizons were shrouded in haze, and you could see blue haze in the headlights. I couldn’t see Sagittarius at all, no stars were visible below Aquilla. The dim red beacon lights on the radio tower tops weren’t too bright by the picnic table, so that’s where I ended up. I was the only person there, quiet and cool, about 11 deg C. Crickets singing, owls hooting and coyotes howling way off in the distance, motors and fans cutting on and off from the antennaes. Maybe a bat winged over. There are dozens of satellite dishes and radio towers around the hill crest there.

I setup three Nikons and a colour video cam. Left them autoclicking for an hour until the main batteries died, then another hour until the spares died.

Shot of a Perseid meteor streaking through Cygnus the Swan. Deneb is the bright blue-white star above.

Overhead the stars were clear and the sky dark with the Milky Way band glowing. Perseus, Pegasus and Auriga to the East over the Steeples were bright. It was great! The meteors were coming down left and right every fifteen seconds! Some bright ones leaving a glowing line that slowly faded. Mostly white, but some green tinged. Some sporatics that didn’t radiate from Perseus.

That zigzag constellation above is Perseus, with two tiny green meteor streaks radiating from there, red at the ends. There is a fainter third meteor.

Above is a photo of a sporatic going through Cygnus the Swan. Deneb the tail at top, Alberio the beak at bottom. Milky way glow. Shots of Andromeda got nothing except the Andromeda galaxy.

I took these photos with a bunch of Nikon D100 DSLR cameras with Tamron 28mm f/2.5 lenses, and a Vivitar 28mm f/2.0 lens. Exposure times were 30 seconds at 3200 ISO using sunlight white balance. I found I needed at least a f/2.8 lens, since when I used a f/3.3 lens a fairly bright meteor only appeared as a faint streak across the photo.

Rick

The Internation Meteor Organization is having their 2015 Conference in Mistelbach, Austria. from August 27 (Thursday evening) until August 30. At that meeting, Bill Ward from Glascow, UK will be presenting this following paper on Video Spectroscopy. He writes:

One of the new observing programmes I’m working on is called “Towards a New Meteor Taxonomy” (under review). For the first time, as video spectroscopy has become so efficient (you’ll see on the poster I got over a hundred last year alone!) that large samples are now a viable prospect.

Shower meteors, by definition, should have similar properties but are there larger “families” within the sporadic population? I think I’ve taken the first step towards realizing this. I’ve found three spectra with almost identical properties. One from 2006 and two from this year.

Take a look at this: Fireball Spectra Discussion between Bill Ward, Martin Dubs, and Koji Maeda. About half way down are the three graphs.

If this doesn’t persuade people that we’re into a new era of meteor observing I don’t know what will!!!

cheers, Bill Ward Glasgow, UK 

See also Martin Dubs article Meteor Spectroscopy Aspekt2015 part2.pdf

POSTER CONTENTS: (partial contents shown)

For full PDF click here: Meteor Spectroscopy IMC2015 poster Bill Ward.pdf

Video Meteor Spectroscopy Kilwinning Spectroscopic Survey for Meteors International Meteor Conference. Mistelbach, Austria. 27th-30th August 2015.  

The KiSSMe project is an ongoing program to secure video meteor spectra on a routine basis year round. In the long term this may identify if there are any discernible compositional groupings amongst sporadic meteors/fireballs.

Currently three WATEC cameras are in use for spectroscopy (2 x 902H2 Ultimate and 1 x 910HX/RC). Each carries a 12mm f0.8 lens fitted with a 600 groove/mm transmission grating. The dispersion of this configuration is approximately 1.2nm/pixel. A further two WATEC cameras are used for general observing (1 x 902H2 Ultimate and 1 x 910HX/RC). Each is fitted with a 3.5 – 8mm f1 lens. Tests are currently underway with a QHY5II-M USB video camera to try and obtain HD images/spectra.

From April 2014 to April 2015, 105 video meteor spectra were captured in 714 hours of observing. Examples of spectra generated by bright meteors are shown here.

Working with members of the Network for Meteor Triangulation and Orbit Determination (NEMETODE) (1), simultaneous spectroscopic and orbit determination observations have been undertaken. This has resulted in the first such combined observation made from the UK.

The spectrum shows strong emission from magnesium, sodium, oxygen and iron. The meteor was determined to have had an orbital aphelion within the asteroid belt.

On June 18 Peter Spaans and I visited the site where the Canal Flats fireball hit, on the Middle White River. Here are some photos of the terrain there. For a closer look, right click on the photo and open it in a new tab

[Map_FireballArea_sm2.jpg] Map showing closeup of the strewn field ellipse. The centre of ellipse marked at “C”. We parked at “P” at a creek at 4.6km.

“Strewn Field” Distribution: Dr. Hildebrand assumes the meteor fragments are scattered in this elliptical area 3km wide by 5 km long, on a logged hillside on the Middle White River. Anything that hit on the East side of the river, would be on a narrow shelf of flat rock, with high rocky cliffs above and bluffs below. The heavier “three pieces” would likely travel to the far end of the ellipse across the river, with 1 and 2kg fragments near the centre, and lighter fragments not travelling as far, scattered along the Western edge.

Russell Ridge: [RussellPanMidBluff1_1537-38-39.JPG] photo of the Western Ridge from half way up the East river bluffs, looking Northwest towards Sinna Creek where it cuts through the notch in Russell Ridge and enters the Middle White River. Note all the dead trees from the forest fire of 2003. The meteor would have smoked in just over the ridge, hitting like shotgun pellets all along Sinna Creek and these bluffs; smacking into ten foot deep snow banks at a terminal velocity of about 200 to 300 km/h. (Initial velocity when it entered the atmosphere was slow for a meteor, around 15km/s, the average fireball enters at 20km/s. For comparison, the space station orbits at 8km/s).

[BluffsWhiteREast_1534sm.JPG] Looking East to the Lancaster Bluffs along the river, from a spot on the old horse trail beside the river. This is where the bigger chunks of meteorite would have hit.

Bigger view of Lancaster Bluffs on the East, with Marconi Peak hidden behind them, from up on Russell ridge where we parked. [PanBluffsE28mm_1526-27-28.JPG]

It’s pretty tangled at the meteor site. There are dead trees blown over from an old forest fire, and a dense crowd of 6 foot tall pine trees newly growing, and a river and four creeks running through it. But a little bit of paradise to hike in, once you’re down on an old horse trail paralleling the river. We gave up on the higher logging areas because of the crowds of small pine trees, and went down to the open river bluffs at the front third of the impact “ellipse” at 5,050 ft. More likelihood there of finding big chunks, and it’s not clogged with close-packed pine trees. The road to the Maiyuk Rec Site at 68km is washed out just before the Mid White bridge, so we crossed the river here over a fallen log.

[LogBridgePete_1536sm.jpg] That’s Peter Spaans crossing the log in the photo. Pete used to work as lab instructor in the Physics Lab at the College back in the 1990s. I found about eight odd looking black rocks but none were attracted to a magnet. And found tasty red strawberries, elk tracks, bear scat. No mosquitoes. The trip was worth it just for the mountain scenery there. Solid limestone mountains rising with sheer slabs of snow tipped peaks. Birds singing, elk, deer, rabbits, porcupines and other wildlife.

Note that there’s a fellow working there for CanFor with a mulcher with caterpillar tracks, cutting four foot wide swathes into the densely planted pine trees for spacing purposes.

GETTING THERE:

Middle Fork Rec Site: Via main road, go to White Swan Lake, which is by Canal Flats, BC (near Invermere BC in the Rocky Mountain Range of the East Kootenay’s.). Follow the gravel logging road to the Middle Fork Rec Site just past Seeta Creek at KM66 on the White Middle fork of the White River Forest Service Road. There was a forest fire there in 2003, and it has been logged since, but the Middle Fork trail was cleared in Aug 2014. At 67km leave the main road and turn left on the Sinna Creek logging road 0.9 km past the Seeta Creek bridge. From there, go 3.1km to reach the edge of the ellipse. The centre of ellipse marked on the map as “C”. We parked at “P” at a creek at 4.6km; crossed it and walked down the next dry creek bed to the Lancaster bluffs.

View from 60km looking North, our destination in sight. [Pan_RussellJoffreMarconi_60km.jpg] That teepee mountain on the centre left is Russell Peak. Snow and glacier covered Mt. Joffre and Mt. Nivelle at centre, and Mt. Marconi at right centre, behind Lancaster bluffs.

WHAT TO LOOK FOR: Carbonaceous Chondrites: comprise only about 2 percent of meteorites known to have fallen to Earth, are typically difficult to recover because they easily break down during entry into Earth’s atmosphere and during weathering on the ground. Look for black or dark grey rocks that a magnet will stick to. The surface may have a thin grayish fusion crust (a thin melted layer one or two millimetres thick) and scattered thumb sized hollows (worn away by atmospheric friction ablation, called regmaglypts). Although some rarer meteorites like the Tagish Lake meteorite looked like charcoal briquettes.

Ignore layered sedimentary rocks (shale, limestone, dolomite) since these require an ocean to form, and this wouldn’t be found on an asteroid in outer space. Also, if it has holes or bubbles inside (like pumice) that was likely from lava flows (basalt-magma) cooled with trapped volcanic gases, on Earth (although there are rare exceptions: a large asteroid like Vesta had volcanoes). Also, ignore rocks containing quartz or calcite, since they form in high pressure, hot watery solutions.

Magnets: Since a lot of carbonaceous chondrite types (CH, CI, CM, CB) contain iron oxides like magnetite, and some metal rich ones contain nickel-iron chondrules, a rare-earth magnet should stick to most. Dr. Hildebrand says: “Even the hydrated carbonaceous chondrite meteorites would stick to a magnet; something like a CV4 like Allende has the least ferro magnetic phases and might not stick, but that lithology looks v. much like meteorites and I would have guessed that this rock was weaker than CV (not that I really know). Only thing to add would be to keep an eye out for a pile of debris rather than just a solid stone – the hydrated lithologies would probably have started to break up by now.”

Photo: from Wikipedia showing some carbonaceous chondrites. From left to right: type CV4: Allende, C2: Tagish Lake (in sample bag on white paper) and CM: Murchison. Chondrite means that inside the rock are silicate chunks ranging in size from 0.3mm to 10mm, surrounded by a fine-grain black rock matrix. The chunks are usually olivine (a magnesium iron silicate common on Earth but quickly weathered) or the chunks can be nickel-iron metal. The black rock matrix is made of hydrous phyllosilicates similar to terrestrial clays, sulfides, and oxidized iron in the form of magnetite. Many contain high percentages (3% to 22%) of water, as well as organic compounds (like bitumen). However there are many types and they are complex and fairly challenging to describe, so for more detail, see: http://www.meteorite.fr/en/classification/carbonaceous.htm, and http://Wikipedia.org/wiki/carbonaceous_chondrite

Value: If a hiker finds a piece, it could be worth a lot of bucks per gram or it may be disappointing. Common iron meteors are only $.50/gram to $5/gram, rarer stony meteorites $2 to $20/gram, and really rare ones $100 or $1000/gram or more, depending if they have embedded gems or if they’re from Mars or the Moon. And some meteors are dense and heavy, so they go a long way. For example, back in 2000, the rare carbonaceous chondrite meteor that landed on frozen Tagish Lake on the B.C.-Yukon border brought Jim Brook, the lodge owner who found it an estimated $850,000. The University of Alberta, with Canada’s second-largest meteorite collection, bought most of the meteorite. For sample meteorite pricing, see http://www.meteorlab.com/METEORLAB2001dev/offering21o.htm The Washington University in St. Louis has a great webpage showing all sorts of meteorites at http://meteorites.wustl.edu/id/metal2.htm.

If you do find a possible meteorite, send a photo to Dr. Hildebrand at the University of Alberta in Calgary. Note that American Meteor hunters have to report to the Canadian Customs, Canada has export restrictions on them.

[meteorite_flow_chart.gif] Above is a flow chart guide designed by Deborah Guedes in Brazil to help identify a meteorite. http://www.lpi.usra.edu/meetings/metsoc2010/pdf/5357.pdf “Regmaglypts” are those worn-away thumb sized hollows in the surface.

Rick Nowell Astronomy Lab Tech College of the Rockies Cranbrook, BC