The Perseid meteor shower peaks in 2 weeks and is already underway

The Perseid meteor shower has been active for a few days now, and is predicted to peak @ 13:19 UT on August 13th.

In fact, NASA's dedicated All-sky Fireball Network picked up a number of fireball class Perseids last night. This diagram from NASA shows their orbits.

Last night, NASA's All Sky Fireball Network detected 17 Venus-bright meteors. The orbits of the meteoroids, color-coded by velocity, are shown in the diagram below. Earth's location is marked by a red starburst:

*snip*

Blue orbits correspond mainly to Perseids. The Perseid meteor shower doesn't peak until August 12-13, but Earth is already in the outskirts of the debris zone of the parent comet, 109P/Swift-Tuttle. By mid-August, rates could exceed 100 meteors per hour. The show, in other words, is just getting started.

Source: spaceweather.com

Note that by " Venus-bright meteors" I think they meant to say "meteors that are at least as bright as Venus".


As the article says, the Perseids are caused by the debris left behind comet 109P/Swift-Tuttle, and we are just on the outskirts of that debris zone right now. Most of the debris that hits our atmosphere and gives us Perseid meteors is actually very small, "sand grain" or smaller sized particles or meteoroids to give them their correct name, but larger meteoroids are also scattered throughout, and even one around the size of a cherry would create an impressive fireball.

There are slightly larger Perseid meteoroids too, but since they are made of very fragile material and hitting the atmosphere at an average speed of around 61 km/s, they completely disintegrate long before they get close to the ground.


When to observe

The short answer is any time after the sun has set between now and mid-August, with the nights surrounding the 13th being best if you want to see the best rates.

The Long answer is - Perseid rates gradually build up over the course of the next couple of weeks, and the peak itself is drawn out compared to most other annual meteor showers, so wherever you are you will have a chance to see relatively high rates, even if the peak occurs during the daytime where you are.

Of course that is providing the weather cooperates, which it often does not when it comes to meteor shower peaks (at least where I am anyway!), but at least with the Perseids it's possible to get fairly good rates in the nights leading up to, and after the peak thanks to "spread out over time" nature of this shower..

Also, there is a visible increase in Perseid rates throughout the night, up till it starts becoming light due to the Perseid radiant which is located in Perseus at the time of the peak having a higher elevation above the horizon later on in the night.

The rates may be higher later on in the night, but it's still worth observing throughout the night on the peak night/nights, as the radiant has already risen by the time the sun has set for mid-northern latitude observers in the Northern hemisphere.

Although the Perseids are not observed in as great numbers from the Southern hemisphere due to the low altitude of Perseus above the horizon, it would still be a good opportunity to try and observe earth grazing Perseids during the peak.

To an observer located in the southern hemisphere, these would appear to shoot up from the northern horizon, or along the eastern/western horizons, but always heading away from Perseus and southwards. Grazers, although infrequent are some of the most amazing and impressive meteors in my experience.


How to observe

Finding a good site to observe from is the key to observing meteor showers. Ideally, you want to be as far away from any cities/towns/villages/any source of light in general as possible, and have clear all-round views free from obstructions like trees, buildings, and hills all the way down to the horizon.

Take a sleeping bag (or two if you are in an exposed location) plus a camp bed or something else comfortable to put your sleeping bag on, and look straight up. Perseids will be visible in all parts of the sky, and by looking more or less directly up, you'll catch many more Perseids than you would if you tried observing while looking low down in the sky.

In the case of Southern hemisphere observers, you would want to be looking upwards but with a slight bias to the north, since that is the direction where earth grazers will become visible.

As with most annual meteor showers, it helps to have patience since there can be lulls in activity, especially outside the peak nights.

Don't forget to look out for long lived persistent trains which brighter Perseids often leave behind them, and if you have a camera, why not try to photograph them. The Perseids have a reputation for being rich in bright meteors and fireballs, making them a good target for photographers. Even so, getting a good shot of one can be frustratingly elusive as I have come to see over the years, but don't let that put you off trying. You never know what you might catch! See below for tips and links.

Good luck!

Related Links

2012 predictions
Mikhail Maslov

Perseid shower info, history, and observations
meteorshowersonline.com
Previous year's ZHR graphs


Basic visual meteor shower observation techniques
How to Observe Meteor Showers
How to View Meteor Showers - How to "See More Meteors"




This great video covers almost everything, but I would argue on a few points that were mentioned:

1. It's usually better to be totally flat when observing meteors since you can catch meteors close to any horizon with your peripheral vision when facing directly upwards.

2. If you live in a warm/tropical climate, you might get away with a blanket (or even less) to keep you warm, but I'd advise putting on multiple layers of warm cloths, and jumping into a sleeping bag if you want to observe for any length of time if you live away from the equator. If you are too warm (unlikely in most cases) then you can always remove a layer of cloths or two.

3. The camera exposure times he mentioned could be at the upper end of the scale if you have any light pollution at you're site and/or depending on your equipment/settings/how you want your photo to appear. It's worth experimenting before hand, but if you are using fast lenses/high ISOs (which you should be if you want to catch any meteors, although you may get lucky and catch a bright meteor anyway), exposures can be as short as 5 or 10 seconds. See links below for more info.


Advanced visual meteor shower observation techniques
www.imo.net...

Photographing meteors
www.abovetopsecret.com...
www.abovetopsecret.com...

General information
www.space.com...
Anomalous Meteor Phenomena

Organizations and mailing lists
www.imo.net...
www.amsmeteors.org...
tech.groups.yahoo.com...

I neglected to include alternate predictions for this year's Perseid peak from Jérémie Vaubaillon, who's predictions suggest the peak may come a slightly over 24 hrs earlier than the prediction I mentioned in my OP, ie on the morning of the 12th. Keep in mind all predictions are in UT (Universal Time), which is the same as GMT, so you'll have to convert to your own time-zone if you are not in the same time zone as the UK.


Source: Jérémie Vaubaillon

So there is some uncertainty as to which set of predictions well be most accurate. My advice would be to hedge your bets and observe on the night of the 11th/12th, and on the night of the 12th/13th if you want to try and catch the peak.

Unfortunately, the moon will be more of a problem if the peak arrives early. For example, on the 11th/12th the moon rises at roughly 23.40 UT, while on the 12th/13th the moon rises at roughly 01.32 UT. Moonlight, as most of you will know, will make it harder to see fainter meteors, and you'll want to try and keep it outside of your field of view as much as possible. Luckily the Perseid meteor stream is usually rich in bright members, and the moon's interference is not as bad as it can be around the peak, so it should still be a good show.

The run-up to the peak night/nights won't be as favorable, since the moon rises earlier on in the night (an hour earlier each successive night away from the peak), and will be high in the sky/bright for the majority of the night, and especially towards dawn, when Perseid rates are usually at their highest.

I am definitely planning to watch the Perseid showers!
I remember seeing Halley's comet and Hale-Bopp when I was little and it stuck with me so I love the sky now!

reply to post by cassiper


I also vividly remember seeing Halley's comet when I was younger, but not Hale-Bopp for some reason.

Hope you catch some nice Perseids this year cassiper

The International Meteor Organization has published a "live" ZHR graph which you can use to get an idea of how high the current Perseid rates are.

Of course it's not actually "real-time" data, so keep this in mind, but it could help in determining when the pea is due, if you check closer to the peak.

Currently, rates are around 10-15 Perseids per hour (as seen under ideal conditions).


Don't forget that you can check the following web sites for images/footage of rece3ntly captured meteors:

NASA's All-sky Fireball Network
Spaceweather.com Realtime Meteor Photo Gallery

Amateur astronomer Thomas Ashcraft caught a nice Perseid fireball disintegrating over New Mexico on the 2nd August. Click here for a clip.

The movie's sound track comes from Ashcraft's dual-frequency meteor radar. It works like this: Radio signals from distant VHF transmitters bounce off the meteor's ion trail. Ashcraft's antennas can pick up those reflections, which sound like ghostly echoes in the loudspeaker of his VHF receiver.

Source: spaceweather.com

It appears that Mikhail Maslov's predictions have been mixed up with last years predictions, and his peak prediction time should be August 12 at 13:19 UT.

This matches Jérémie Vaubaillon's predictions much better, so it's looking like Saturday night/Sunday morning is the time to observe if you are in Europe/Africa or N/S America.

It's looking like it'll be clearing up here in the UK just in time for the peak night, so with any luck I should get some pics this year. If I do I'll post them up here.

Good luck

bump

Not long to go now. Hope everyone has a good peak. I'll be away over the next few days, so I'll probably see you all again on the other side.

Im gonna be spending some time at the beach tonight so Ill make sure to make myself comfortable in the sand and look up at the sky. Im hoping its a nice clear night and I get to see something

Thanks for the post

reply to post by blackmetalmist


Perseid rates have picked up significantly over the last couple of nights, so despite the moon, you should get to see a few at least.

Hope you ave clear skies, and good luck.

As promised, here's an update.

We had mixed luck this year. The pre-peak night (10th/11th) was clear, but we couldn't find any clear skies for the peak night. On the night that was clear, we set up the cameras and got in a few hours observing till it started to cloud up a little just before dawn.

For a pre-peak night it wasn't bad. I wasn't really counting, but I'd estimate that I saw perhaps 50+ meteors in around 5 hours of observing, including sporadics and members of other showers. That also includes 3 or 4 fireball class meteors, the best of which was not a Perseid but a sporadic.

Here are some of the best images from that night.



Crop from the photo above.




Crop from the photo above.


My partner and I saw this fireball, which was the brightest Perseid of the night that was observed visually.


Crop from the photo above.


Besides Perseids, we also observed and captured lots of satellites and satellite flares like this unidentified flare below, which is a composite of three separate exposures. I intend to post the rest in another thread when I have the time.


There weren't many bright Perseids that night, but we managed to catch the brightest one we saw. Just a shame that we were clouded out on the peak night/nights (the peak was a bit more prolonged than expected) or I'm sure we would have caught lots more.

If anyone out there missed out this year, don't fret - it looks like there are more favorable Perseid peaks in the years to come, and possibly even an outburst or two. In the mean time, the Geminid meteor shower (which is usually stronger than the Perseids) is only a few months away.

reply to post by FireballStorm

I saw two like that here in Townsville.
One at around 10.30 and the second at around 11.30. Sunday night (12th)

Love and harmony
Whateva

It was a rather weak showing here in the NorthWest... I watched for 5 hours through the peak time and maybe saw 25 to 30 small ones. Last night I saw two large ones that were really cool. I also seen the space station like 5 nights in a row...

reply to post by FireballStorm

Awesome...

img820.imageshack.us...

Cool the way it flares thru the spectrum from green to white to orange to red. Gone in a moment. Been cruising the solar system for eons and zzzt in a flash. I wonder how long that track is in the sky? I we assume a 20 km/s velocity (we really don't know), and a 100th of a second burn time, then the math I don't know comes out to...

Good questions, and thanks for the comments/reply intrptr

Originally posted by intrptr
Cool the way it flares thru the spectrum from green to white to orange to red.

Yeah - that aspect of some meteors has always fascinated me. The same colour changes are actually often observed in meteors that have a high enough velocity such as the Leonids, and the reasons behind it are quite well understood.

A paper on the subject can be found here:

The photographed colours of Leonid meteors

Originally posted by intrptr
Been cruising the solar system for eons and zzzt in a flash.

Probably not quite "eons", but computer models strongly suggest that many of the Perseids we see were ejected from comet 109P/Swift-Tuttle 100's and in some cases a few thousand years ago.

Originally posted by intrptr
I wonder how long that track is in the sky? I we assume a 20 km/s velocity (we really don't know), and a 100th of a second burn time, then the math I don't know comes out to...

It's not too hard to estimate since we know that Perseids are all traveling at more or less the same velocity, which is around the 60 km/s mark.

We also know that most Perseid meteors don't last more than 1 second, and in this case, since I observed the meteor in question, I can confidently say that that particular Perseid lasted between 0.5 and 1 second.

So the track in the sky is probably somewhere around 30-60 km in length.

Keep in mind that the track is probably no where near parallel to the plane of the camera sensor, so perspective will make it look shorter than it actually is.

reply to post by FireballStorm

So the track in the sky is probably somewhere around 30-60 km in length.

My mind just went zzzt!