Best planetarium app for tablet

[TCampbell]

Loads of apps will do the very basic view of the sky.

A while ago I did a presentation where I briefly showed the basic features of planetarium apps (which they all have) and quickly brushed that aside so I could show the features that really separate the pack.

Sky Safari adds a number of interesting features that most other apps don't have.

On iOS they support Augmented Reality ... but what I particularly like is their ability to adjust the blend of the camera vs. AR view *and* the ability to slide the map to match the sky (e.g. if you notice the position of the moon in the AR view doesn't match the camera view you can slide the map to match the camera and this causes everything to be extremely accurate (because the compass in the phone may be off by a few degrees.)

Sky Safari has multiple platform versions for phones, tablets, computers, etc. but but you can store your configuration in the cloud. This means you can plan your observing lists on the computer, then use the phone or tablet in the field because they share data. The same holds true of the equipment list (configure your scope & eyepieces, etc. for field-of-view overlays is shared.)

The database detail in Sky Safari is amazing ... pick an object and you can pull up a ton of data on that object -- more than I find in most other apps.

And here's something REALLY unique... with Sky Safari you can leave the planet (I suspect many people have no idea you can do this). You can put your self in orbit around other other objects or view the solar system from different locations. This is really cool when you're trying to get an idea of the path of a comet to figure out when/where best to view it.

Many solar system objects have surface detail as well (zoom in the moon and you'll see the names of all the craters, etc.)

The Plus and Pro versions of Sky Safari (which aren't free) can be used to control go-to telescopes. The basic version doesn't have that feature. Apart from that, the most significant differences between the versions is the database size. The free version is pretty much everything you could hope to see with your eyes or binoculars. The Plus version is pretty much everything you can see doing visual observing with an amateur telescope. the Pro version database is so large that it shows objects that would probably only show up in long-exposure images.

I have a couple of Raspberry Pi astronomy appliance/gadgets. One is the ZWO ASIair, the other is the StellarMate. Both of these are similar in that they have all the software built-in to control a scope, auto-guider, acquisition cameras, filter wheels, etc. etc. But the ASIair doesn't have any planetarium capability. Instead, the built in a Sky Safari bridge in their software. This allows your phone/tablet to control the scope ... while it's also being controlled by the ASIair for image acquisition. They don't support any other app -- just Sky Safari. StellarMate is similar except they do include the KStars app running on the appliance, but they also include a Sky Safari bridge (but only Sky Safari ... nothing else is supported.)

Even among the hardware vendors ... Celestron, Meade, & Orion, leverage Sky Safari. The Celestron Sky Portal, the Orion StarSeek, and the Meade StellaAccess apps ... are actually all special editions of Sky Safari. These vendors partner with Simulation Curriculum to get special editions of Sky Safari that enable telescope control ... but only for their brand of telescope (vs. the edition you can buy which supports pretty much every go-to scope).

[OzEclipse]

I concur with all of Tim's comments. I have a few things to add about GOTO. I use a SkyFi with Sky Safari to control my Takahashi EM200. The SkyFi can with an appropriate connector cable, create a wireless interface for a bewildering array of mounts. For most mounts, the GOTO system is calibrated by a 1,2 or 3 star alignment using the routine on the GOTO handset then Sky Safari controls the GOTO using the app.

Another class of scopes such as my EM200 have encoders and a serial interface but no GOTO handset and therefore no built in multi star alignment.The result is that for my mount, the polar alignment needs to be pretty accurate before the one star alignment available through Sky Safari will give accurate GOTO pointing.

In response to this requirement, I developed my own new and simple method of polar alignment which I call APPS ( Artificial Projected Pole Star ). This technique enables very accurate polar alignment in less than 5 minutes. It has been a big help for my AP as well. After a 5 min APPS alignment and with the EM200's accurate drives which seem to be much better than the PE spec of ±5 arc sec, I can do unguided astrophotography with focal lengths up to and sometimes longer than 400mm. I have been using this for almost 1 year now with great success.

The SkiFi interface also works with other applications. One of these is called ASTROMIST which does have built in multi star alignment. The multi star alignment is in the app so you can't do a multi star alignment in ASTROMIST then use it in Sky Safari. Provided your mount has a multi star alignment in a GOTO handset, the above problem does not apply.

Joe