Preparing for a stargazing night
Depending on where you live, think about bringing warm clothes for a stargazing night – and not only in winter. Even in summer, nights can get cool and humid. This is why I always bring extra clothes. In winter I usually make sure I have hot tea in a thermos jug with me. You’ll need a torch, ideally with the option of red light – to help preserving the dark adaptation of your eyes. If you are planning to observe the night sky from a remote place, think about your personal safety. Also, be aware that especially in remote areas, there are lots of wildlife animals around. So make sure not to disturb them unnecessarily.
The right moment
For night sky observation – and weather permitting – it’s best to wait until astronomical dusk when the sun is at 18 degrees below the horizon. The duration of twilight (civil, nautical & astronomical) varies considerably from season to season and from the latitude of your observation site. There are a number of websites and apps you can use to check local times. Personally, I use the Astro Locator App and a number of other apps (more information to follow). Usually, I set up my telescope mount right after sunset when there is still enough daylight. Ideally, and in order to leave your equipment as it is, you have a dome in your garden – something I’m planning to invest into soon, so stay tuned.
Observing the night sky
It doesn’t necessarily take a telescope to observe the night sky. Depending on where you are living (city/rural area) & local sky glow, you can observe the Milky Way, different constellations, the Moon and Planets with your naked eyes. You can use binoculars – I use the Kern Swiss Army binoculars 8×30 mm.
In the dark, the pupils of our eyes expand to a diameter of between 5 mm – 7 mm (depending on your age). Make sure to allow sufficient time for your eyes to become adapted to the dark and, if needed and whenever possible, only use red light afterwards.
For orientation, it will be useful to know the cardinal points (N/E/S/W) as well as a few bright stars. In the Northern Hemisphere Polaris is certainly a good starting point but it is not always well visible – again, depending on your seeing location. Alternatively, in winter look out for: Sirius or Rigel, in summer for Altair, Daneb or Vega. Over time, you will get familiar with constellations and planets and at what local time they appear in the night sky depending on the season and location you live.
Since the earth is rotating around its own axis as well as orbiting the sun, the night sky changes constantly. There are a number of apps you can download on your smartphone to help you find interesting celestial objects. I like Sky Guide but there are plenty of other apps. Stellarium for example is a free open source planetarium you can use on your computer, incl. Mac. It has many useful features and is an excellent source to plan celestial observations in advance. It is now available for smartphones, although the iOS version is a bit more sophisticated and not for free. Download for: iOS (Stellarium PLUS) / Android (Stellarium Mobile free version).
Check your local weather forecast in advance and: observe the sky yourself. A forecast is a forecast and over time, you learn to anticipate somewhat the weather by observing the clouds, the wind…, so always observe the sky. For more detailed data check Meteoblue and type in your location. It gives you an idea of Clouds, Seeing conditions, Bad layers, Jet stream and Temperatures as well as Celestial bodies. You’ll get an overview like this (data will obviously vary depending on time and location):
Star trails
In this star trail photography you can see the apparent motion of the stars. The trails are actually the result of the rotation of the Earth around its own axis. To take this picture I placed my DSLR camera on a tripod (you can use any other type of camera). It’s an exposure of 431 seconds at f/1.8 and ISO 800 – which is by the way a bit too much. It also largely depends on the lens you are using and the degree of light pollution in your location. So settings vary greatly depending on the equipment you are using and the location you are – and not to forget if it’s a night with moonlight or not.
The gear I: Astrophotography with a DSLR camera & tripod
As mentioned above, all you need for stargazing is your naked eyes – and ideally a dark site. You can also choose a location between two hills (if there are any) so that direct light from nearby villages and/or cities is a masked.
If you want to take pictures of the Milky Way or constellations like Orion or Perseus etc., you can do that for example with a DSLR camera. It has its limits though – especially for Hydrogen-alpha waves – this is why I now also work with a so called dedicated Astrocamera (just in so please be patient). I
A stable tripod is key. I use a Gitzo Mountaineer. There are certainly other brands that offer the same quality and stability. But it’s better to invest in good quality. My first tripod was cheap and fell apart 3 weeks after purchase with an expensive Nikon lens totally damaged – unfortunately, not the camera. So it makes sense to invest in stable equipment.
For the lenses it’s really up to you and the object you want to take pictures of as well as what you want to achieve – from tele to ultra-wide-angle, anything is possible. Personally, for Milky Way pictures, I enjoy using the Sigma 14 mm f/1.8. It’s a wide-field lens with a remarkable aperture. Given the aperture and depending on your eyesight/age, focusing is not always easy so make sure to make a few test shots first.
For the camera settings, it really depends on your location, the camera and the lens you are using. Unfortunately, my sky is quite light polluted even though I live in a rural area (more on that on my LightPollution site). The more light pollution you have, the less ISO is usually better – start at around ISO 400. Also exposure time depends on the lens you are using – with the Sigma 14 mm f/1.8, you get great results even with shorter exposure times. Unless you want star trails, follow the “500 rule” (for a full frame camera). So for a focal length of 14 mm I would not go beyond 30-35 seconds shutter speed unless I have guiding (see below). And then, it depends on what object you want to take pictures of. For the Milky Way, 25 seconds with my 14mm f/1.8 Sigma is enough. For Moon pictures, the rules are totally different. Depending on the Moon phase, I generally use ISO 50 (if it is Crescent Moon you could probably use ISO 100) and very short aperture time. In the end, it is trial and error and you will learn very fast.
The gear II: Astrophotography through a telescope
Looking and taking pictures through a telescope is another option. Choosing a telescope, a mount and the infinite number of accessories can be quite challenging. There are many informative websites out there where you find useful information on different types of telescopes: refractors, reflectors, catadioptric telescopes… Also, don’t forget that even in the 2020s, there are great Astronomy Shops (brick & stone). In my area, my reference is Zumstein in Bern (if you live in Switzerland and near Bern). They have an astronomy section and people there are usually competent and will give you useful advice.
Reflectors have a mirror at the rear of the main tube and they are generally quite affordable. My first telescope was a SkyWatcher reflector – also known as a Newtonian telescope. The second I have is also a reflector but with a larger aperture. It is very bulky and therefore, I find it hard to handle.
The Takahashi FSQ-85EDX – an apochromatic refractor – is very compact. It has been especially designed for astrophotography – although it is also excellent for the observation of celestial objects. The quality of the pictures is absolutely stunning. It comes with a Flattener. Reducer & Extender are optional. For setup details check my review.
Tripod and mount
A stable tripod and mount are paramount. Just as for the telescope, there are many different types of mounts on the market and choosing the “right one” may not be obvious. I’m using a so called “German equatorial mount”. From my experience the mount is probably the most important piece you’ll purchase. However, with any mount, it takes patience to do a proper polar alignment. My Avalon Linear really works well for polar alignment, especially combined with the Astro Locator and Polar Align App Pro Version) – I’m done within a few minutes.
In any case, reach out to friends or family members who may have a telescope and enjoy a moment out there with them. In addition, there are astronomy clubs, people on social media like Twitter, Tumblr etc. or YouTubers who, in my experience, are happy to share their advice with you. I owe a lot to fellow Twitter friends who gave me invaluable advice over time, so rest assured.
Editing
I’ll publish an astrophoto editing section as soon as possible. Beware, it takes a lot of time to stack and edit astropictures. But it’s worthwhile and a constant learning process – as astronomy and astrophotography. I’m currently using RegiStar, PixInisght, Lightroom as well Photoshop with Plug-ins for photo editing. As far as PixInsight is concerned which can be overwehelming, I can recommend the book by Warren A. Keller “Inside PixInsight” – it’s very comprehensive. When it comes to CCD cameras and narrowband (H-alpha, Oiii, Sii) processing it has its shortcomings though but check for tutorial videos on YouTube.
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