Urban Orion


Urban Nightscape – Orion over Calgary

On a very clear night, Orion shines over the skyline of Calgary.

As I live in the country, it’s not often I shoot the stars from urban sites, and certainly not from downtown Calgary. But the combination of a clear night and a speaking commitment in Calgary provided a chance to see what was possible under ideal conditions.

The lead image is real – I did not paste an image of the sky taken at some other time or place over the skyline image.

However, the sky image is a longer exposure (10 seconds) than the ground (3 seconds) in order to bring out the stars better, while keeping the city lights under control with no overexposure. So it is sort of a high dynamic range blend.

The other factor that helped reveal stars as faint as shown here (fainter than what the naked eye can see) is the use of a light pollution reduction filter (a NISI Natural Night filter) to penetrate the yellow sky glow and provide a more pleasing colour to the sky.

Earlier in the night, during twilight when urban light pollution is not so much of an issue, I shot the waxing crescent Moon setting over the skyline.

Crresent Moon over Calgary

This is a panorama image made from high dynamic range blends of various exposures, to again accommodate the large range in brightness in the scene. But I did not use the NISI filter here.

These images demonstrate how you can get fine astronomy images even from urban sites, with planning and timing.

To that end, I used my favourite app, The Photographer’s Ephemeris, to determine where the sky elements would be as seen from a couple of viewpoints over the city that I’ve used in the past.

The blue spheres in the left image of TPE in its Night mode represent the Milky Way. That chart also shows the direction toward Orion over the city core.

The right image of TPE in its Day mode shows the position of the Moon at 6 pm that evening, again showing it to the left of the urban core.

Other apps are capable of providing the same information, but I like TPE for its ease of use.

Clear skies!

— Alan, January 20, 2018 / © 2018 Alan Dyer / AmazingSky.com 

 

The “Blue Moon” over Calgary


The Full Moon of July 31, 2015, an infamous “blue Moon”, the second Full Moon of July, rising over the skyline of Calgary, Alberta. This is one frame of a 480-frame time-lapse sequence taken with the Canon 60Da and 28-105mm lens. The location was Toronto Crescent.

The much-publicized “Blue Moon” of July rises over the skyline of Calgary.

Last night, July 31, many people looked east to see a wonderful moonrise. Did it look different than any other moonrise? No. But did it look great? You bet.

I set up my cameras at a site in northwest Calgary, picked for its sightline looking east-southeast over the downtown core of Calgary and directly toward the moonrise point.

I used the software The Photographer’s Ephemeris to plan the location and angles. It is wonderful for making sure you are in the right place at the right time for catching a photogenic moonset or moonset.

Here’s the screen shot from TPE that showed me where to be Friday evening. The blue line aims to the moonrise point.

IMG_2473

Of course, despite the planning the Moon did not look blue! Blue Moons, as they have come to be defined, never do. The term now means the second Full Moon in a calendar month. We had a Full Moon on Canada Day, July 1, and then enjoyed a second July Full Moon one lunar cycle later on July 31.

I shot the scene with two cameras, each shooting hundreds of frames for time-lapses, from which I extracted still images.

A short 1-minute music video of the result is here at Vimeo. Enlarge the screen and be sure HD is selected.


As a technical note, for the processing I used the latest version 4.2 of LRTimelapse and its new “Visual Deflicker” workflow which very nicely smooths out all the frame-to-frame flickering that can plague daytime and twilight shots taken under Auto Exposure.

While the shutter speed does constantly decrease, it does so in 1/3rd-f/stop steps, yielding stair-step jumps in brightness. LRT smooths all that out, with v4.2 doing a much better job than earlier versions.

Thanks for watching!

— Alan, August 1, 2015 / © 2015 Alan Dyer / www.amazingsky.com 

Sunset in the City — This is Only a Test!


This is one for the time-lapse geeks!

One of the trickiest subjects for a time-lapse sequence is a smooth and seamless day-to-night transition. Exposure times vary from fractions of a second before sunset to several seconds at night fall.

How to do it? Manually shifting exposures is too much work and prone to error. Putting the camera on Automatic can work but inevitably results in an effect known in the time-lapse world as “flickering.” The camera’s automatically-judged exposures aren’t consistent from frame to frame so the final movie shows minor bright/dark flickering, making it look jerky.

For this test sequence of sunset over the Calgary skyline, I tried a new toy for the first time, as a solution.

The device is called the Little Bramper (for Bulb Ramping). It is a custom-made intervalometer that fires the camera shutter every few seconds (at whatever interval you desire). Nothing new there. But what’s unique is that it can be set to slowly increment the exposure time by as little as 1/1000th of a second from frame to frame, gradually increasing the exposure (“ramping” it) to accommodate the darkening scene. The result is a smooth transition from day to night with no flickering.

This was my first use of the Bramper and it wasn’t without its glitches. The shortest exposure the Bramper can provide (it always controls the camera thru its Bulb setting) is about 1/10th of a second (I had no idea camera shutters can fire as quickly as that even on Bulb).

But at the beginning of a sequence like this, with a bright sky, achieving that exposure (still quite long) means using a small f-stop, a slow ISO speed, or a neutral density filter, or all of the above. But as the sky darkens and exposures lengthen, exposures would become too long to fit within the desired interval between frames (typically no more than 5 to 10 seconds for a smooth sequence). So, to shorten the exposures you then have to open up the lens, switch to a faster ISO, or remove the ND filter, while also commanding the Bramper to quickly reduce its exposure time, all in one exposure cycle (i.e. 5 to 10 seconds) so as not to lose or ruin frames. Takes some coordination and practice (hit the Bramper’s button, adjust the camera, all within 5 seconds), and I didn’t get it right the first couple of times.

But overall, for a first test, the sequence turned out very well. The $80 Little Bramper does the job, though it does take careful monitoring through the sequence, not just to perform the exposure swaps, but to also watch that the ramping rate (adjustable on the fly) matches what the scene is doing and you aren’t under- or over-exposing. It’ll take a little more practice, but the results certainly are worth it.

It’s another neat tool in the time-lapse arsenal.

— Alan, August 10, 2011 / Movie © 2011 Alan Dyer