Star Trails, Plane, Meteor and Cosmic Ray

Posted on December 16, 2017 by Benoit Guertin

Simply setting up a camera to take a series of images of the night sky can pick up a lot more than a few stars.

trails_secondaries_small If you have a wide-angle lens, and live near a large city there is a good chance that some aircraft will fly into the field of view. The linear streak and alternating lights are a dead give-away of a plane having crossed the camera’s field of view. If you don’t have the alternating lights, it’s mostlikely an orbiting satellite reflecting sunlight.

Meteors are also somewhat of a common occurrence. These are easily recognized by their characteristic increasing than decreasing brightness as they burn up in the upper atmosphere. The meteor in the image above is from the Geminid shower.

The last artifact comes for outside our solar system, it is cosmic rays. The CCD or CMOS sensor of your camera works by performing an electric read-out of photons captured by the lens. Cosmic rays are high-energy sub-atomic particles that have traveled through space and managed to make it through the atmosphere down to us. The one in the photo above just happens to hit my camera sensor. As the near light-speed sub-atomic particle smashes into atoms on the sensor it looses energy, freeing up electrons which register as “light” by the CCD. Most of the time the cosmic ray will hit the sensor straight on, but sometimes it impacts at a shallow angle and causes a series of pixels to “light” up, as in the photo above.

Take time to examine your photos, you never know what surprises you may find.

Setup for the Geminids

Posted on December 14, 2017 by Benoit Guertin

With the Geminids peaking tonight and a clear sky after two nights of snow, I charged the camera battery and got a quick setup going to take some pictures of the sky. As for any nigh sky photo, both lens stabilizer and auto-focus is set to OFF and focused manually at infinity. Then found a corner of the yard shielded from stray lights and planted the tripod, roughly aiming the camera 70deg up and pointing east (the constellation Gemini was rising at 10pm).

However at -15C outside, the old battery wouldn’t last very long. I left it running for about 30 minutes, taking 20 seconds exposure at ISO 800 with a 17mm F4 lens. The camera is now thawing (covered with frost after bringing it indoors) and will wait until tomorrow before checking the pictures out.

Setup for the 2017 Geminids

In the brief moments that I was outside I caught a 2-3 meteors and one really bright one (easily visual magnitude -4). So even living in the city, the Geminids are visible and accessible to all. With my feet deep in snow I wasn’t dressed well enough to hang around in the cold wind to watch the show for long. So I hope the camera managed to capture a few.

Watching the Geminids

Posted on December 10, 2017 by Benoit Guertin

It’s that time of the year again: the Geminid meteor shower. It is visible almost all the month of December, however the best and peak viewing, with up to 120 meteors an hour, is between December 12 and 15. It should be a good year because we are heading towards a new Moon on December 18th, so no bright moon to ruin the show.

This meteor shower is called the Geminid because the radiant (apparent direction of travel in the sky) of the meteors is centered on the constellation Gemini. However the source of the debris is not a comet like most other meteor showers, but an asteroid: 3200 Phaethon. The asteroid and orbit were discovered in 1983 and is too good of a match with the Geminids to be anything other than the source of the debris. However its makeup is closer to asteroid belt material, so it may very well be a 5km chunk from a larger asteroid, with all the associated debris.

To watch the Geminids, the best time is past midnight as the constellation will rise east around 10pm. The higher it is in the sky the better. The Geminids do regularly create fireballs: bright displays that can exhibit colour and even leave a smokey trail, so observation even in light polluted city sky is possible.

Here are some tips for the observation:

Dress to be warm. You’ll be sitting still in the cold night. Nothing will get you indoors faster than the shivering knowing that warmth is only a few feet away.
Lay down or recline in a chair. Standing and looking straight up is very uncomfortable and quite the strain on the neck.
Give yourself a good 15 minutes for your eyes to adjust to the darkness If you give up after 2-3 minutes, your eyes are still adapting to night vision and will miss the fainter meteors.
Find a spot away from sources of lights. Of course heading out of the city is best, but if you can’t, just find a spot in your backyard without the glare of street lights and neighbors’ porch lights. That also means no electronic screens to ruin your night vision.

You can also setup a camera on a tripod to see if you capture some of the meteors. Grab a short focal length, remove auto-focus and go for a 10-20 second exposure setting.

Clear skies!

Does Earth Influence the Sun?

Posted on December 7, 2017 by Benoit Guertin

I recently came across an article in the french Science & vie magazine, where a reader asked if Earth influences the Sun. I found it rather interesting, and while I had my doubts I still wanted to know more about it.

sun-earth

The reader wasn’t the first to wonder if there was any interaction, various models and observations have been put forward since the late 1800s. We often read about two bodies interacting in space. The first exoplanet was discovered due to its gravitational influence on its star causing it to wobble. This type of gravitational influence works when two bodies have a mass within one or two orders of magnitude of each other. But in the case of our Sun, it is 99.86% of the solar system’s mass, and most of the remaining is taken up by Jupiter and Saturn. Therefore from a gravitational perspective Earth has no effect on the Sun.

But could the 11 year period in solar activity, characterized by the rise and fall of number of observed sun spots be caused by the planets? The exact source of that periodicity has yet to be clarified. Well a team of researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) put out a paper in 2016 after demonstrating that every 11.07 years the planets Venus, Earth and Jupiter are aligned. Coincidence?

They explained that while the effects are rather small, the repeated nudging could be enough to tip the Sun’s magnetic field instabilities one way or the other causing this 11 year solar cycle that we observe, much like an object entering into resonance. In this case it’s the Sun’s magnetic field acting like a dynamo that would resonate due to the planet’s alignment every 11 years.

However many are skeptical about any real effect pointing that the source of the Sun’s magnetism comes from deep within, while the planet’s effect, if ever, would be limited to the Sun’s surface. But the crushing blow is when you look at fact that the solar cycle varies between 7 and 14 years, the number 11 just happens to be the average over the last 24 observed cycles. Unfortunately the three planet’s alignment don’t vary by that amount.

In the end, the Sun is still king and does what it wants in this solar system, regardless what the planets say or do.