A few month back I ran into problems trying to identify certain deep sky objects that showed up on my pictures. Stellarium – although I like it – is good at searching for known objects, and not by coordinate search, and I cannot script it the way I want. Nova.astrometry.net is also a very useful tool, but it does not have all the objects I grew able to image. I built my own deep sky database, a strong search tool, but that one is a search tool only with no visual sky, although I linked it to Aladin Lite. Aladin and Simbad – I like them, but they lack an easy coordinate search – and I really mean easy when I say so. Obviously, Aladin and Simbad are mainly for professionals, I guess. Stellarium has a photo planning feature, but – even though it can show Aladin’s sky, still no button by default -, it doesn’t fit my hands. So I felt like everything I need is out there somewhere, but the dots are just not connected.
I wanted to have all my knowledge at my fingertips, everywhere, and finally to have a robust output, that doesn’t fail when going offline: paper. Needless to say, my thoughts converged towards a website.
So I wrote my own photo planner, based on the Aladin Lite API and my DSO search engine and Simbad’s coordinate search.
I built DSO to know what I need to know: it has two huge databases, the dso on the surface and the stars, mainly hidden, to aid constellation search. I extended the dso namebase with some aliases, with Hungarian and Romanian translations and so on. And based on geolocation, the Sun’s and the Moon’s position, it is able to propose photo targets.
My dso can make advanced selections, like, it’s long even to write it down: list all the planetary nebulae from the Messier and Caldwell catalogs that tonight, while the Sun is below -18 deg altitude, will be at least at +20 deg altitude, ie nicely over the horizon. When I type catalog:mc type:pn minaltindarkness:20, I get the table below (for my geolocation Kolozsvár, Romania, and the date of this article). Couldn’t find out there anything even close to this feature.
|C 63, NGC 7293||Helix nebula, Hélix-köd, Csiga-köd||PN||Aqr||7.3|
|M 27, NGC 6853||Dumbbell-nebula, Súlyzó-köd, Nebuloasa Dumbbell||PN||Vul||7.4|
|C 55, NGC 7009||Saturn nebula, Szaturnusz-köd||PN||Aqr||8|
|C 6, NGC 6543||Cat’s Eye Nebula, Macskaszem-köd, Nebuloasa Ochi de Pisică||PN||Dra||8.1|
|C 22, NGC 7662||Blue Snowball, Kék Hógolyó||PN||And||8.3|
|M 57, NGC 6720||Ring nebula in Lyra, Gyűrűs-köd, Ring Nebula, Nebuloasa Inel||PN||Lyr||8.8|
|C 15, NGC 6826||Blinking planetary, Blinking Planetary Nebula||PN||Cyg||8.8|
|C 39, NGC 2392||Eskimo nebula, Eskimo Nebula/Clown Face Nebula, Eszkimó-köd/Bohóc-köd||PN||Gem||9.1|
|M 97, NGC 3587||Owl nebula, Bagoly-köd||PN||UMa||9.9|
|M 76, NGC 650||Little Dumbbell Nebula, Barbell Nebula, Butterfly Nebula, Cork Nebula, Kis Súlyzó-köd||PN||Per||10.1|
|C 56, NGC 246||Skull nebula, Koponya-köd||PN||Cet||10.9|
|C 2, NGC 40||Bow-Tie Nebula, Csokornyakkendő-köd||PN||Cep||12.3|
It is nice, I like it. It has, by default a more useful view of the sky than any other program out there, including Stellarium and Google Sky. It also has some amazing name resolving features. And it has an API – more like hinted than well documented, but it is there.
Some other data
Sensor size and focal length, ignoring distortions. And field rotation. Spherical math, here we go again.
All the above needed to become something that needs no internet connection, no adaptation-ruining displays, no electricity, nothing. I wanted paper. And on that paper, everything I might need while under the starry sky having nothing more than a red flashlight (the autoguider’s laptop in my case is an old netbook, nowhere near the horsepower needed for softwares like Stellarium) and the goto mount.