The Moving Stars of the Northern Hemisphere


Arizona Star Trails - Circumpolar Looking North

I present a montage of time-lapses illustrating the motion of the sky in the Northern Hemisphere. 

Any stargazer should be familiar with how the sky moves, with stars rising in the east and setting in the west.

From the northern hemisphere, when we look north we see the sky rotating counter-clockwise around the North Celestial Pole, near Polaris. As you’ll see in the video, even Polaris moves, though not much over the night. The stars that never set, but just move across the northern horizon, are the circumpolar stars.

When we look south we see the seasonal constellations, the ones that rise and set, and change over the seasons.

I shot the images for these sequences from southern Arizona, in early December 2015.

So the night starts with the summer stars setting in the west and the autumn stars dominating the sky. But then Orion and the winter stars rise and march across the sky over the night, setting before dawn, as the spring stars rise.

The south-looking movie is a dusk-to-dawn sequence. Note the Zodiacal Light in the west at right in the early evening, then reappearing in the east at left before dawn brightens the sky, and as Venus and the Moon rises.

Also note the moving bands of red and green airglow, a natural phenomenon of the upper atmosphere.

 

I posted a matching set of movies in my previous blog post, shot from the Southern Hemisphere. But here’s the link to the movie.

 

Both sets of movies were shot from nearly identical latitudes – about 31°, but 31° N for Portal, Arizona and 31° S for Coonabarabran, Australia.

As such the Celestial Poles appear at equal altitudes above the horizon. And the angles that the stars rise and set at in relation to the horizon are the same.

But the direction they move is opposite. When looking 180° away from the Pole, the seasonal stars move from left to right in the Northern Hemisphere, but from right to left in the Southern Hemisphere.

Visitors from one hemisphere to the other are bound to get turned around!

— Alan, August 25, 2016 / © 2016 Alan Dyer / AmazingSky.com

 

The Old Hearst Church in Moonlight


The Big Dipper over Hearst Church

The Big Dipper and the Pole Star shine above the moonlit historic Hearst Church.

Tuesday was a productive evening of shooting in the moonlight. One of the best from the night pictures the Hearst Church in the rustic town of Pinos Altos in the Gila Forest of southern New Mexico.

The Big Dipper stars shine at right, with the Pointer stars in the Bowl aiming at Polaris above the Church. Illumination is from a waxing quarter Moon and from some decorative lights in the yard next door across the street.

The Hearst Church was opened in May 1898 and indeed is named for the famous Hearst family. Money to build the church was raised by the local mining families with a major donation from Phoebe Hearst, wife of the mining magnate and senator George Hearst. Phoebe was also mother to newspaper tychoon William Randolph Hearst, the inspiration for Orson Welles’ movie Citizen Kane. Gold that decorates Hearst’s mansion in California came from the family mine near Pinos Altos.

As the mining boom went bust the Methodist church lost its pastor then its congregation. It is now an art gallery and home to the Grant County Art Guild. See their website for details on the historic church.

While I know many of my blog’s followers enjoy the photos for their own sake, lots of folks also like to learn more about the technical aspects of the images.

So with this blog, and selected others in future, I’ll present a bit more of the “how-to” information.


How the Image Was Shot and Processed

Taking the image could not have been simpler. It is a single 45-second exposure at f/2.8 with the 24mm lens and Canon 6D at ISO 800, on a static tripod, about as basic as you get for nightscape shooting. There is no fancy stacking or compositing.

The trick is still in the processing, however. Here is a breakdown of the Photoshop CC 2014 file and its various layers. Every aspect of the processing is non-destructive. No pixels were ever harmed in the process. Every adjustment can be tweaked and modified after the fact.

Heart Church Processing Layers

< Star spikes top layer added with “Astronomy Tools” actions from Noel Carboni.

< Sharpening layer created from stamping the final layers into one layer using the Command-Option-Shift-E command, then a High Pass filter applied, blended with Soft Light and masked to sharpen just the ground.

< Adjustment layers for colour, brightness & contrast, and levels, applied to the sky and ground separately with masks, created using Quick Selection Tool and Refine Edge.

< A Clone & Heal layer for wiping out the power lines & power pole, using the Patch & Spot Healing Tools.

< The base image, opened from the developed Raw file as a Smart Object, with noise reduction and sharpening applied as Smart Filters.

I know this won’t explain all the processing steps but I hope it provides some idea of what goes into a nightscape.

All this and much more will be explained in an upcoming half-day “Photoshop for Astronomy” Workshop I’m presenting Saturday, May 9. If you are in the Calgary, Alberta area, consider joining us. For details and to register, see the All-Star Telescope web page

Also, my ebook featured below has all the details on shooting and processing images like these.

Clear skies and happy shooting!

— Alan, January 29, 2015 / © 2015 Alan Dyer / www.amazingsky.com 

Canola Field Stars


Circumpolar Star Trails over Canola Field (July 26, 2013)

Stars in a blue sky wheel above a ripening field of yellow canola.

It’s been a couple of fine nights of nightscape shooting under the light of the waning Moon and clear skies.

I’ve been shooting from no more exotic location than my local rural neighbourhood, travelling for 5 minutes to spots near one of the many canola fields growing nearby. I wanted to grab some nightscapes over the  fields before they lose their yellow flowers and turn green.

The feature image above looking north is from a time-lapse sequence and stacks several images with the “comet trail” effect, to show the northern stars turning about the North Star.

Big Dipper over Canola Field #2 (July 26, 2013)

This image, also a frame from another time lapse with a longer lens, shows the Big Dipper above that same field but in an exposure short enough to prevent the stars from trailing. You can now make out the familiar Dipper pattern.

This is a very Canadian scene, with the Big Dipper high in a northern latitude sky, and with the foreground crop a Canadian one – Canola was developed in the 1970s at the University of Manitoba. The “can” in canola stands for Canada. Pity there was no aurora.

– Alan, July 28, 2013 / © 2013 Alan Dyer

 

Meteor and Windmill in the Moonlight


A rare bright meteor pierces the northern sky beside a spinning windmill in the moonlight.

I shot this Thursday night, August 30, as one frame of 300 or so shot for a time lapse sequence. Having a camera taking hundreds of frames at rapid interval, as you do for a time-lapse movie, is the only way to capture the chance and fleeting appearance of a bright meteor like this.

You can see the Big Dipper behind the machine and Polaris, the North Star, directly above the well-placed meteor.

I drove out to the new Wintering Hills Wind Farm now operating northeast of me and found a machine I could get close to. And they are huge! This is a sequence from a dolly shot I took. But the other camera was on a fixed tripod and I’ll stack those images into a long star trail scene, to get the circumpolar stars spinning alongside the windmill. But the machine was turning so fast that even 4 second exposures in bright moonlight blurred the blades more than I would have liked.

— Alan, August 31, 2012 / © 2012 Alan Dyer