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Astrophotography in Extremely Dark Skies

Introduction

By far and away the biggest improvement we can make to our astrophotography is visiting the darkest skies possible. In Scotland, we are extremely lucky. If we move away from the central belt between Glasgow and Edinburgh, it is quite easily to find suitable skies in which to practice the craft; and the further we move from large towns and cities, the better it gets.

Glen Lyon - Nikon Z8 with 24/1.4 prime lens on a Star Adventurer Star Tracker Mount. Exposure is 3 minutes at f/3.5

The Bortle scale gives us a rough guide on what to expect with regards to night sky quality. From 9, being horrdenously bad inner city skies, where we are lucky to see the odd star, to Bortle 1, where we can see really faint and distant objects, some even with the naked eye. You might be surprized to learn that the above picture is Bortle 2; yes there are even slightly better skies than this! Anything between 1-3 is truly excellent however. At the lower end of the Bortle scale, we can also easily expect to discern individal star colours:

Cancer, Mars, Gemini - Shot with a Nikon Z8 and Tamron 35/1.4 lens wide open for 60 seconds

Gemini in particular, is a constellation I plan to shoot a lot more of. This was a fairly impromptu picture, as I had waited a little longer than I should have to shoot it, causing it to be a little low on the horizon this night. Of course, that horizon is in the hills of Glen Lyon, and just over that ledge is a massive drop into the glen. So it’s all about positioning here. Shooting constellations is a delight in astrophotography, however the pictures have to be given careful consideration.

Cassiopeia over Urlar Moor

Looking north into Kenmore, Scotland, sits a little fishing hut at Urlar Moor. It is the perfect subject to frame up the recognisable Cassiopeia constellation as I have done here. Consider the Bortle scale as a general guide of night sky quality. Remember that looking in certain directions will often yield lower light pollution. Here, looking North, means I am not fighting through light pollution from the centra belt cities in Scotland. However, when aurora shows up, as it has done in this image, for the most part it allows us to shoot in more light polluted skies anyway, because by it’s nature it tends to fill the sky with colour, in this case, purples.

Perseus, Cassiopeia and Andromeda

I started taking pictures on my other camera whilst one was doing a tracked exposure quite some time ago. It keeps my mind on something whilst standing in the freezing cold, and often the different thought process that goes along with it, can allow for something unique to be had. Here, I didn’t bother to turn the tracker off to expose the foreground, because I was pressed for time to get back to what I was doing (ie, the headline shot of this article), and the fact that this image is about the sky, not the ground.

The Plough / Big Dipper Asterism

The plough really looks amazing in Bortle 1-2 skies when it is at Zenith (overhead).

Three in Line - 2 minute sky exposure at f/2,8. Six minute foreground, blended.

Lastly, here is a beautiful Glen in Perthshire which always brings me back, time and time again. The sky was pink with very faint aurora.

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Steve