It was a great night for shooting meteors as the annual Perseids put on a show.
For the Perseid meteor shower I went to one of the darkest sites in Canada, Grasslands National Park in southern Saskatchewan, a dark sky preserve and home to several rare species requiring dark nights to flourish – similar to astronomers!
This year a boost in activity was predicted and the predictions seemed to hold true. The lead image records 33 meteors in a series of stacked 30-second exposures taken over an hour.
It shows only one area of sky, looking east toward the radiant point in the constellation Perseus – thus the name of the shower.
Extrapolating the count to the whole sky, I think it’s safe to say there would have been 100 or more meteors an hour zipping about, not bad for my latitude of 49° North.
The early part of the evening was lit by moonlight, which lent itself to some nice nightscapes scenes but fewer meteors.
But once the Moon set and the sky darkened the show really began. Competing with the meteors was some dim aurora, but also the brightest display of airglow I have even seen.
It was bright enough to be visible to the eye as grey bands, unusual. Airglow is normally sub-visual.
But the camera revealed the airglow bands as green, red, and yellow, from fluorescing oxygen and sodium atoms. The bands slowly rippled across the sky from south to north.
Airglow is something you can see only from dark sites. It is one of the wonders of the night sky, that can make a dark sky not dark!
The lead image is stack of 31 frames containing meteors (two frames had 2 meteors), shot from 1:13 am to 2:08 a.m. CST, so over 55 minutes. The camera was not tracking the sky but was on a fixed tripod. I choose one frame with the best visibility of the airglow as the base layer. For every other meteor layer, I used Free Transform to rotate each frame around a point far off frame at upper left, close to where the celestial pole would be and then nudged each frame to bring the stars into close alignment with the base layer, especially near the meteor being layered in.
This placed each meteor in its correct position in the sky in relation to the stars, essential for showing the effect of the radiant point accurately.
Each layer above the base sky layer is masked to show just the meteor and is blended with Lighten mode. If I had not manually aligned the sky for each frame, the meteors would have ended up positioned where they appeared in relation to the ground but the radiant point would have been smeared — the meteors would have been in the wrong place.
Unfortunately, it’s what I see in a lot of composited meteor shower shots.
It would have been much easier if I had had this camera on a tracker so all frames would have been aligned coming out of the camera. But the other camera was on the tracker! It took the other composite image, the one looking north.
The ground is a mean combined stack of 4 frames to smooth noise in the ground. Each frame is 30 seconds at f/2 with the wonderful Sigma 20mm Art lens and Nikon D750 at ISO 5000. The waxing Moon had set by the time this sequence started, leaving the sky dark and the airglow much more visible.
It’s Perseid meteor shower time. Here are tips for seeing and shooting the meteors.
What are the Perseids?
They are an annual meteor shower, perhaps the most widely observed of the year, that peak every year about August 12. They are caused by Earth passing through a dust stream left by Comet Swift-Tuttle, last seen near Earth in 1992.
Each “shooting star” is really a bit of comet dust burning up in our atmosphere as it ploughs into us at 200,000 kilometres an hour. They don’t stand a chance of surviving – and none do.
All Perseid particles burn up. None reach Earth.
When are the Perseids?
The peak night of the Perseids this year is the night of Wednesday, August 12 into the early morning hours of August 13, with the peak hour occurring about midnight Mountain Daylight Time or 2 a.m. on the 13th for Eastern Daylight Time.
For North America, this is ideal timing for a good show this year. However, a good number of meteors will be visible the night before and night after peak night.
Even better, the Moon is near New and so won’t interfere with the viewing by lighting up the sky.
In all, except for the mid-week timing, conditions this year in 2015 couldn’t be better!
What do they look like?
Any meteor looks like a brief streak of light shooting across the sky. The brightest will outshine the brightest stars and are sure to evoke a “wow!” reaction.
However, the spectacular Perseids are the least frequent. From a dark site, expect to see about 40 to 80 meteors in an hour of patient and observant watching, but of those, only a handful – perhaps only 1 or 2 – will be “wow!” meteors.
Where do I look?
All the meteors will appear to radiate from a point in the constellation of Perseus in the northeastern sky in the early hours of the night, climbing to high overhead by dawn.
So you can face that direction if you wish, but Perseids can appear anywhere in the sky, with the longest meteor trails often opposite the radiant point, over in the southwest.
How do I look?
Simple – just lie back on a comfy lawn chair or patch of grass and look up!
But … you need to be at a dark location away from city lights to see the most meteors. You’ll see very little in a city or light-polluted suburbs.
Head to a site as far from city lights as you can, to wherever you’ll be safe and comfortable.
How do I take pictures?
To stand any chance of capturing these brief meteors you’ll need a good low-noise camera (a DSLR or Compact System Camera) with a fast (f/2.8 or faster) wide-angle lens (10mm to 24mm).
Sorry, keep your point-and-shoot camera and phone camera tucked away in your pocket – they won’t work.
Set up you camera on a tripod, open the lens to f/2.8 (wide open perhaps) and the ISO to 800 to 3200) and take a test exposure of 20 to 40 seconds. You want a well-exposed image but not over-exposed so the sky is washed out.
Set your exposure time accordingly – most cameras allow a maximum exposure of 30 seconds. Exposures longer than 30 seconds require a separate intervalometer to set the exposure, with the camera set on Bulb (B).
Take lots of pictures!
To up your chances of catching a meteor, you need to set the camera to shoot lots of frames in rapid succession.
Use an intervalometer to take shots one after the other with as little time between as possible – because that’s when a meteor will appear!
Barring an intervalometer, if you have standard switch remote control, set the camera on High Speed Continuous, and the shutter speed to 30 seconds, then lock the remote’s switch to ON to keep the camera firing. As soon as one exposure ends it’ll fire another.
What else do I need to know?
• Focus the lens carefully so the stars are sharp – the Live Focus mode helps for this. Focus on a bright star or distant light.
• Aim the camera to take in a wide swath of the sky but include a well-composed foreground for the most attractive shot.
• Aim northeast to capture meteors streaking away from the radiant. But you can aim the camera to any direction that lends itself to a good composition and still capture a meteor.
• To increase your chances, shoot with two or more cameras aimed to different areas of the sky. Meteors always appear where your camera isn’t aimed!
• Be patient! Despite shooting hundreds of frames only a handful will record a meteor, as only the brightest will show up.
Can I track the sky?
If you have a motorized equatorial mount or a dedicated sky tracking device (the iOptron Sky Tracker and Sky-Watcher Star Adventurer, each about $400, are popular), you can follow the stars while taking lots of shots. This avoids the stars trailing and allows you to use longer exposures.
The video above shows a Star Adventurer tracking the sky as it turns about its polar axis which is aimed up to a point near Polaris. Click the Enlarge and HD buttons to view the video properly.
Polar align the tracker, but then perhaps aim the camera to frame the summer Milky Way overhead. Take lots of 1- to 3-minute exposures, again at f/2.8 and ISO 800 to 1600. Some exposures will pick up meteors – with luck!
Tracking then stacking
Later, in processing, because the sky has remained fixed on the frame, it’s then possible to stack the images (using a “Lighten” blend mode on each image layer) so that the final composite frame contains more meteors, for an image with lots of meteors captured over an hour or more of shooting.
While it is possible to stack shots taken on a static tripod to produce such a meteor composite, doing so requires a lot of manual cutting, pasting and aligning of meteor images by hand. The result is a bit of a fake, though I’ve done it myself – the image at top is an example, though with only a trio of meteors.
A couple of Perseid meteors streak across the moonlit sky above Mt. Cephren in Banff National Park.
The night before the peak of the annual Perseid meteor shower was very clear for the first couple of hours. On Monday, August 11, I positioned myself at the shore of Lower Waterfowl Lake, at a roadside viewpoint on the Icefields Parkway in Banff National Park, Alberta.
I had two cameras going, one on a fixed tripod aimed west in hope of catching some meteors in a few frames. Two did, and the main image is a composite of those two frames, as the Perseids shoot over the pyramid peak of Mt. Cephren.
Later, the Space Station also flew over, accompanied by the European ATV cargo ship, captured here in a stack of 18 frames from the 555-frame time-lapse, showing their pass from west to east (bottom to top) of the composite image. The gaps are from when the shutter was closed for 1 second between the 15-second-long exposures with the 14mm ultra-wide lens.
In all, it was a warm and beautiful night, with the normally busy viewpoint all to myself all night, under the light of the nearly Full Moon.
It was quite a night, and a wonderful dawn. This was the scene at the end of a night of falling stars.
A trio of Perseid meteors zips down at left, while at right a trio of solar system worlds rises into the pre-dawn sky. The overexposed waning Moon is flanked by Jupiter above and Venus below. Jupiter shines near the Hyades star cluster and below the Pleiades cluster.
I took this shot (it is actually a composite of three shots, each with its own meteor) on the morning of Sunday, August 12 on the peak night of the annual Perseid meteor shower, widely publicized this year due to the lack of a Moon for most of the night, and the convenience of falling on a weekend. The scene is looking east over Lake Minnewanka in Banff National Park, Alberta, one of the few places in this part of the Rockies you can look east to a reasonably unobstructed sky.
Notice the glitter path on the water from not only the Moon but also Venus.