Observer pro is really an invaluable application to use for choosing targets in the night sky. It contains objects from all the large catalogs Messier, Caldwell, Herschel, NGC, and IC. You can also browse objects by type including Galaxies, Galactic Nebulae, Planetary Nebulae, Open Clusters, and Globular Clusters. The above views show the listing view and object view. In the listing view you can see the objects visibility during the 24 hour period. It's depicted by an orange/green bar. The best viewable time for that object is depicted in Green. Bright blue depicts day, dark blue depicts moon light, and black is no moon during the night.
You'll notice some gaps in the orange/green bars shown above and that's because I have my local horizon measured in the application. The application uses mixed reality to view through your phone camera and trace the horizon of your sky (in this case, my back yard, which has several large trees that block my view).
It's best to position yourself where your telescope would be, then use your phone as a viewfinder and draw your local horizon tracing any objects that might be in the way. The result should show something similar to the above. Once done and saved, you can turn on local horizon, and have it show when objects go behind obstacles in your horizon.
These views depict where the object is during the night sky, and show a finder view to help you see what the sky and object location look like with no obstructions. Other views depict detail of each chart available to each object, as well as detailed information on each object.
Detail view showing the rise and set of the sun and moon, as well as the object rise and set time, and depicted in green is the best available time for imaging with no moon.
This view shows detailed information on the object, including it's magnitude, location, and what type of object it is.
To top it all off, you can export your local horizon out of the application and convert it to a horizon file for use in Sky Safari. I have my local horizon loaded into Sky Safari 6 Pro on both my iPhone and my Mac desktop computer.
Here's my local horizon file loaded into Sky Safari 6 Pro. To export your horizon file, you must download a converter program (from Joshua Bury the creator of Observer Pro), and also download a script to run the converter from Processing.org, it will take your horizon file and output a PNG that can be imported into Sky Safari.
I highly recommend Observer Pro to anyone that owns an iPhone. It's an invaluable resource that allows for easily scanning the objects lists to see what's visible during the night sky. It also has a handy night mode for use in the field.
