You may already know my astronomy catalog search engine, the DSO. It includes all the catalogs we amateurs use: the Messier, Caldwell, NGC, IC, Arp, SH2, Collinder, Melotte, Abell planetaries, it even grabs the list of exoplanets from a wiki page to always be up to date. But this is not all. It includes some ugly formulae to know about the position of the Sun and the Moon, and do some math based on the geolocation of the user. The DSO however is more like a text mode tool, or an API. It is good to just look up what Messier 51 or NGC 7000 is. Anything more complex requires some heavy wizardry even I don’t master and need to look up in the help I fortunately did write.
But there is the Aladin Lite with its powerful API, hosted on the University of Strasbourg website, on which I built my Photo Planner. You probably already know that too. I programmed it to be a nice frontend for the DSO’s API, meaning that it handles the GPS, the calendar, and you are always one click (and not some command line voodoo) away from finding out what is being viewed on the screen. Beyond DSO, it also uses the Aladin’s search engine and the Simbad engine to solve coordinates and object names. And all that happens under the hood, without the user caring about the details.
And you can also look into the future (technically DSO can, not the photo planner) and list an object’s visibility telling you the favorable dates to photograph it. For example a year of the Pleiades will give a sorted list of dates, when to image the famous cluster. Obviously, the feature is meant for less known objects, like the supernova remnant included in the Abell planetaries catalog at index 85. For the near future, instead of yearof: we can use monthof: to get day by day information. To see meaningful results and not just under the horizon, near September click on M31, and near March on M84. M84 and M31 are visible from almost every inhabited place on Earth. Or if you, for some probably benign yet still weird reason only you know, live in one of the containers in Antarctica, and for some more weird reason I’m not sure I want to know, you happen to check my website, try the Carina Nebula.
These features are math-intensive, lots of trigonometry and floating point operations, not really meant for PHP, so the calculations take a heavy toll on my webserver (which is tasked with other stuff too). I have invested some work in optimizations, but be a realist: taking an astrophoto takes many hours, so a few seconds don’t matter. Ergo be patient and get ready for timeouts and the need to constrain your searches.
Let the fun begin :D