12 Essential Mac Apps for Amateur Astronomers

What are the essential Mac apps for the backyard astronomer? In this article, I've listed some of the most notable OS X apps that round out a complete technical package for the amateur astronomer.


The goal here is to recommend some very good, respected apps for beginners that are in typical use on the Mac. It would be impractical to list every available app, and I recognize that many advanced amateurs will have their own favorites.

I've defined six categories of apps: a sky chart that does telescope control, astronomy weather forecast, satellite look up, session planning, image processing and last but not least, a superb scientific calculator.

1. Sky Chart & Telescope Control. There are several Mac apps that combine a sky chart with telescope control for compatible GoTo telescopes. They include, for example, Equinox, SkySafari, TheSkyX and Starry Night. Based on previous reviews of the Mac and the iPad versions, as well as the technical energy being put into continuous development, I have come to consider SkySafari Pro or SkySafari Plus by Southern Stars the best option for the Mac. Here's a review of the Mac version by a well-known amateur astronomer.

Image Credit: Southern Stars, SkySafari Plus for Mac.

Southern Stars also offers SkyFi, a Wi-Fi telescope controller to operate a GoTo telescope with a Mac (or PC, iPhone, iPad, or iPod Touch and, with some limitations, Android.) A description and list of compatible GoTo telescopes is on the SkyFi page.

2. Astronomy Weather Forecast. Before you can start planning for an observing session, it's helpful to know what the weather is going to be that evening as well as the phase of the moon. The weather will help determine a start time and what clothing you'll need. The phase of the moon will tell you whether you'll be doing some casual observing of the moon and planets during a bright full moon or perhaps some deep sky photography at new moon or after the moon in partial phase has set.

Two sites that help with that are 7Timer! and Clear Sky Chart.

3. Satellite Info. Satellite info is good in case you'd like to try to catch one with binoculars and need the azimuth and rise time. Some amateurs have used this data to anticipate and photograph the International Space Station from the ground with stunning results.

Check the Heavens-Above website.

4. Observational Planning. Once you've figured out the weather and what you want to look at or photograph, it's helpful to have a session planning app. Your start time and the positions of the selected objects will determine when they go below the horizon, so you'll want to start in the western sky before they set. A planner will help with all that.

AstroPlanner is a well regarded astronomy session planning app for the Mac. Here's a review.

Image credit: AstroPlanner.

5. Photographic Image Processing. If you move from introductory visual astronomy, simple gazing or things that can be done visually, such as sketching or double and variable star observations to astrophotography, you'll need a collection of apps that can process your images for research or publication.

Note that astrophotography will require some extra equipment and lots of trial and error to gain experience. There are plenty of good books that will help you get started. For example, "Digital SLR Astrophotography" by Michael A. Covington.

Here are some image processing apps, in no particular order, that are typically used by amateur astronomers.

  • Photoshop. For merging photos, enhacing in various ways, creating animated GIFs to show object movement over time, and so on.
  • GIMP. An open source Photoshop alternative.
  • Pixelmator. Another strong image editing app. Some people, including me, prefer Graphic Converter.
  • Lynkeos Often, a better image can be obtained by digitally "stacking" or combining several shorter duration photos on a Mac/PC rather seeking to obtain one long duration photo. This app does a good job of that for individual images.
  • Keith's Image Stacking. This app can stack multiple frames from a single video file.

Image Credit: Lynkeos.

6. Scientific Calculator. Many astronomers have a good, physical scientific calculator or two handy, such as the HP-35s from Hewlett Packard. However, if you prefer to have one on your Mac, I give my highest recommendation to PCalc by James Thomson.

Amateur astronomy is an enormous field that encompasses a long scientific history, huge choices for equipment and a great many books on the subject. As I mentioned above, it's virtually impossible to cover the possibilities in a single article of this size. However, if you want to get started or already have some initial experience with a telescope, the links here should be helpful.

Next up: a similar look at iOS Astronomy apps for the iPad.


Starry sky teaser image via Shutterstock.