I use several (Android). I have SkySafari 4 Pro. It is produced by the same people that produce SkyPortal and has more objects in its database. I have SkyPortal too.

I have Distant Suns and Mobile Observatory (both free apps). And of course Google Sky map. Mobile Observatory has a lot of features and is really good. Distant Suns is not as good.

In Mobile Observatory, there is a sky view. I like it when I what to make sure I can identify the bright stars. It is a less busy view and shows the constellations and star names. And the more you expand, the more star names that show up.

Later, I close that one and go to SkySafari or SkyPortal since they can show the DSO's.

And I use a tablet for this. The cell phone screen is just too small.

Now the problem I run into is that with my progressive lens glasses, when I hold the tablet up at arms length, it is out of focus since I am using the top portion of my glasses. The stars are in focus, but not the screen. If I take my glasses off, the screen is in focus, but I can not longer see the stars in focus. Bugs me.

And speaking of focus, if I look through the telescope eyepiece (without glasses), the astigmatism is bad enough that the stars are never quite nice points. With glasses, the progressive lens makes the star change as I move my eye around a bit. But when I look at them on the LCD of my Sony camera, they are perfect points, and all I need to do is to carefully focus them to the smallest size. And it doesn't take much adjustment to go past that perfect spot.

I also have dedicated reading glasses and dedicated distance glasses, but each of those posses a problem using the scope at night. Oh how I remember the what the sight through a telescope looked like when I was young! Started with a 3" reflector when I was around 12, and later to an Edmund Scientific 4.25" reflector a few years later.

I'm Android here. I have a full page of Astronomy App's (16) I can use.
GPS Coordinates - gets me those pesky Longitude and Latitude numbers for eggzackary where I am.

Clear Sky Droid Wonder what the sky will be like? It is pretty accurate.

Stellarium Mobile Has a bagillian stars in it. And stuff too numerous to list. And Night Vison, turns the screen red.

Sky Guide More to play with. Searchable. Fun.

Polar Alignment What cleared up a LOT of fog about use of the AVX Polar scope for me. Two nights ago I got HOURS of accurate tracking on the ring nebula. Halleluiah!

Star Walk 2 Sometimes you like something enough to buy it. :oops: Although I prefer free.

Compass Compass that has a telescope mode. Because sometimes you just want to know which way is North damn it? Good Polar Alignment starts with a good aim. And this one gives you a flat compass, but the caveat is the telescope mode that lets you see through your phones camera so you can pick an aimpoint out there before the stars come out.

Messier Pro Basically a black and white picture catalog of objects to program into your deep sky section of your mount under Messier. It got me on target with quite a few. When I find one, or the mount does actually, I add it to the favorites and it's mine forever. Currently I have 7 I've found from my very own back yard in my favorites.