SkySafari for macOS Frequently Asked Questions

This page contains answers to the most frequently asked questions about SkySafari for macOS.

  1. I have more than one Mac computer (or I bought a new Mac). Can I run SkySafari for macOS on more than one Mac?

    If you bought SkySafari, SkySafari Plus or SkySafari Pro from the Mac App Store, you should be able to download it again onto any other Mac computer that is authorized for your iTunes account, free of charge. But it needs to be the same iTunes account as on the computer where you first bought the software!

  2. I already bought your iOS version of SkySafari for my iPhone/iPad/iPod Touch. Can I get a free copy of (or discount on) the macOS version?

    No. SkySafari for macOS is a complete rewrite of our iOS app, running on a computer with a different kind of processor, under a separate operating system with a very different user interface. Our Mac and iOS apps are sold through different app stores. Even if we could offer you discount, Apple won't let us.

    We hope that this won't dissuade you from purchasing our Mac version separately. Most desktop astronomy programs competing at SkySafari's level of sophistication cost hundreds of dollars - ours is priced, like our iPhone apps, at the cost of a pizza. At these very low prices, we hope that SkySafari for macOS will provide you with tremendous value, in spite of being a separate purchase.

  3. How does SkySafari for macOS differ from SkySafari for iOS?

    Feature-wise, they are very similar. SkySafari for macOS can do a few things that the iOS version can't (like print hard-copy sky charts), and vice-versa (like use the compass/accelerometer - which don't exist in desktop Macs - to give you a "live view" of the sky.) You can find a complete list of the differences between the versions of SkySafari for macOS on this page, and SkySafari for iOS on this page.

    However, SkySafari for macOS has a completely rewritten user interface, with 100% native Cocoa macOS controls. It "looks and feels" like a proper macOS application, just like SkySafari for iOS "looks and feels" like a proper iPhone app. And the experience of running SkySafari on a Mac with a full-sized monitor, keyboard, and mouse is qualitatively different from running it on a tiny iPhone screen. We've already brought SkySafari's fluidity and smoothness from the iPhone to the Mac, and the much faster processor and graphics card in your Mac will make it run that much better.

    Our best suggestion is just to try out the basic version of SkySafari for macOS. It only costs a few dollars, and if you like it, there's more where that came from!

  4. I have a planetarium dome, and a projector with a fish-eye mirror. Can I project SkySafari's output onto my planetarium screen?

    Yes! Paul Bourke has created instructions for how to warp SkySafari's output for projection onto any planetarium dome using Quartz Composer.

    Using a Mac with such a projector, the Mac's primary screen lets the planetarium operator control all display functions. Isolate the control panels and menu bar to the primary screen. Use the projector as the second display, letting the warped sky display on the projector at a resolution of 1200 x 1200 or larger.

  5. I'm searching for Comet X or Asteroid Y, but it's not in your database. How can I find it?

    Recently-discovered comets and asteroids may not be present in SkySafari's original database. To add them, go to the Settings menu's Solar System item. Then tap the Update Orbit Data button. This will import the latest asteroid/comet data from the Minor Planet Center. If you still can't find your asteroid or comet, the MPC may not yet have added it to its export files. Try again in a few days.

    Please note: this feature is only present in SkySafari Plus and Pro. It is not available in the basic version.

  6. I'm trying to observe a satellite, or the International Space Station. But SkySafari's predictions for where the satellite is/when it passes overhead are wildly wong. What's the problem?

    Your satellite orbital elements are probably out of date. To update them, select to the Settings menu's Solar System item, then tap the Update Orbit Data button at the bottom. This will import the latest satellite data from the CelesTrak. Satellite orbits change rapidly due to atmospheric drag, and due to perturbations from the Earth's non-spherical gravity field, so it's important to update your orbit data frequently - at least once a week - to get accurate predictions for them.

    Please note: this feature is only present in SkySafari Plus and Pro. It is not available in the basic version.

  7. You also might want to make sure that your location, time zone, date/time, etc. are correct - if you've accidentally set your observing location to California, but you're really in Colorado, that will make a big difference!

  8. SkySafari is predicting a rise/set time for the Sun/Moon/some other object which is clearly wrong. Is it broken?

    No - this is really basic celestial mechanics that has been tested many times over by our users. The problem is almost certainly that your location, time zone, or the date/time are set incorrectly. Go to SkySafari's Settings view to adjust them.

    If your Mac's WiFi is turned off, SkySafari may be unable to determine your current location. A common symptom of this problem is that your latitude, longitude, and time zone are all zero. To correct this, make sure your Mac's WiFi is turned on, and that you are connected to the internet. Even then, auto-location using WiFi may fail - in that case, just enter your location manually.

    If rise/set times are off by exactly one hour, the problem is almost certainly that your time zone is incorrect, or that SkySafari thinks daylight savings time is in effect when it really isn't (or vice versa). Governments frequently change the rules for Daylight Savings Time, and while we try to keep up with them, we may have missed something. You can manually set your time zone, and turn SkySafari's automatic daylight savings time correction ON or OFF, in SkySafari's Settings > Date & Time view.

  9. I'm running SkySafari on my Mac and none of the objects are labelled. What's going on?

    SkySafari on Mac uses the Arial font for its labels. If you or another application have disabled Arial, SkySafari cannot use it. Check the Font Book application to see if Arial is there and enabled.

  10. I'm using SkySafari to control my telescope. But the directional arrows don't work - I get an error message that says "Use the telescope's hand controller". What's up?

    Some telescopes (for example, the Celestron Ultima 2000 and original NexStar 5/8; and the Argo Navis) lack external commands for directional motion. Even though they are mechanically capable of doing so, their control language has no command to (for example) "move north" or "move south". When these telescopes' manufacturers add those commands, we will be happy to support them!

  11. How do I get my own horizon panorama into SkySafari? Can you show me an example?

    Read the Help file included with the program, under the Settings > Horizon & Sky section! Briefly: first use a program like Photoshop to create a panorama from individual pictures. Your finished horizon panorama must be a 4096 x 2048 pixel image in PNG format, with alpha (transparency) indicating clear sky vs. opaque ground. North is at the left edge; south is in the middle. Then go to the Horizon & Sky settings in SkySafari, click the + button next to the menu of panoramas, browse to the select your panorama PNG file, and open it.

    Here's an example, sent to us with permission by Roger Greenwood in Massachusetts, USA. Click the preview image below to view the full-sized PNG, which you can import into SkySafari as an example:

    Click the preview image above to view and download the full-sized PNG of Roger's Back Yard.

    Joshua Bury, creator of the Observer Pro iOS app, has created a web-based application that converts a numerical horizon representation (altitude/azimuth points saved as an Observer Pro .hzn file) into to a panorama that can be used in SkySafari. It's not as accurate as a well-done photographic panorama, but it is really easy to create, especially if you've used Observer Pro to measure your horizon.

  12. The horizon is not visible! But I've got "show horizon and sky" checked, and/or a panorama selected, in my Horizon & Sky Settings. What's wrong?

    If you're running SkySafari Plus or Pro, make sure your coordinate system is set to Horizon coordinates. Look in your Coordinates settings. If set to Equatorial, Ecliptic, or Galactic coordinates, the horizon will not be shown. This is deliberate - these other coordinate systems do not align to your local horizon, so it would appear skewed at a weird angle. A printed star chart uses equatorial coordinates, and does not show the horizon either. SkySafari is no different.

  13. Can SkySafari compute the exact angular separation between two objects in the sky?

    Yes! SkySafari Plus and Pro can do this, but the basic version cannot. There are two ways:

    1. Click the first object to select it, then double click the second object. This turns on measurement mode. A blue line is drawn from one object to he next with the angular separation. Clicking and dragging on the second object will allow you to move the end point to another object. To exit measurement mode just click anywhere else in the chart.

    2. Select the first object by clicking on it or searching for it. Then select the second object (also by clicking or searching). Finally, click the Info button on the main toolbar. The Object Info data table shows the angular separation from the 1st object to the 2nd object, and the position angle. It also shows the 2nd object's angular separation and position angle from the Sun, and from the chart center.

  14. Some double stars don't show their companion when I zoom in. Why is that?

    The only stars we plot on the chart are the ones in SKY2000, Hipparcos, and Tycho 2 catalogs (and GSC2, in the Pro version). If your star isn't in those catalogs, it won't be displayed.

    The only exception to the above are stars whose primary is in the above catalogs which also happen to have orbits in the 6th Binary Star Orbit catalog. If that star has an orbit, and its companion isn't already obviously listed as a separate entry in SKY2000/HIP/TYC2, then we generate a separate binary companion for it.