Notes on observing the milky way

Notes from Kevin Palmer at Dark Site Finder and Matt Quinn at PetaPixel.

What is it?

CC-by-nc-nd by Bryce Bradford

Kevin Palmer:

Every star you can see with the unaided eye is located within the milky way. […] But when most people talk about “seeing the milky way”, they are talking about the core of the galaxy. Located in the constellation Sagittarius, this is the brightest part of the milky way. Dust lanes, nebulas, and star clusters are all more concentrated in this area.

Where is it?

CC-by-nc-nd by David Kingham

Kevin Palmer:

The milky way rises in the southeast, crosses the southern horizon, and then sets in the southwest. So you will want to choose a viewing site that does not have any major cities in that direction. Even if the sky overhead is very dark, a light dome from a city can ruin the view if it is located to your south.

Matt Quinn:

When planning my outing I’ll use a light pollution map to help me scout good locations to shoot the night sky. When I’m on the go I use an iPhone app called Dark Sky Finder.

Kevin Palmer:

Above 50° north or so it’s more difficult to see the milky way. It will be much closer to the southern horizon even at its highest point. […] On the other hand the farther south you live, the higher up in the sky Sagittarius will rise. Those in the southern hemisphere are privileged to see the milky way high overhead with much more detail than can be seen in the northern hemisphere.

When can we see it?

CC-by-nc-nd by Diana Robinson

Matt Quinn:

The time of year will affect what parts of the Milky Way you see. What part of the world you live in will also determine what you see as well. […] For example, in the Northern hemisphere where I am, the galactic core — the brightest part of the Milky Way — isn’t visible at night in the winter months, but come April the core is high enough in the night sky to be captured.

I use an augmented reality iPhone app called SkyView to help me plan my shoot. It allows me to search for the Milky Way and more importantly change the time and date so I can see what position the Milky Way will be in at that given moment. Planning to shoot the Milky Way is important because your night will end short if what you want to capture isn’t visible when you go out.

Kevin Palmer:

To see a dark sky all night long, you want to go stargazing during the new moon. A 1st quarter moon will set around midnight. So the hours after that will be dark. A 3rd quarter moon will rise around midnight, and the hours before that will be dark.

How to check the weather for observing the night sky?

CC-by-nd by Lukas Schlagenhauf

Matt Quinn:

Your starry photo shoot is very weather dependent. You just have to embrace that it is what it is. If you know the Moon isn’t in phase or visible, and you know it’s the right time of year to go Milky Way hunting, then check your 5 day weather forecast to see if you have a clear night in the near future.

If things are looking good I then refer to an absolutely amazing website that provides an astronomer’s weather forecast for the next 24–48 hours. It shows you the cloud cover, humidity, temperature and so on so you can be more confident that you will get good results on your shoot. Terrible weather can be a huge disappointment to any astrophotographer, so consult your astronomer’s forecast regularly. The website is called Clear Dark Sky and it has thousands of locations around North America. If you don’t live in North America, you may have to consult your weather service to see if they offer an astronomer’s forecast like Environment Canada does.