Amazingly good data-collation site

[fivemack]

http://sky.esa.int

It's like Google Earth for the sky, but better:

* Aggressively multi-wavelength (the GALEX near-ultra-violet sky and AllWISE mid-IR skies are quite excitingly different; the Fermi gamma-ray sky gives a good idea of how hard gamma-ray astronomy really is). Take a look half a degree west of 60 Serpentis and see how the view changes as the wavelength goes up from optical to submillimetre! The "Mellinger Colour" sky is done with a good CCD camera and a 50mm, from dark-sky sites in Texas and South Africa, and I'd call it one of the crowning achievements of amateur astronomy.

* Incorporates the image archives from Hubble and the ISO satellite

* Source lists - zoom in and you can get it to superimpose all the GAIA or Tycho sources known in this area of sky, then point at the little square and get an information box with magnitudes.

The only missing feature is a 'what's this' button, but if you transcribe the coordinate into http://simbad.u-strasbg.fr/simbad/sim-fcoo you get to query some nice comprehensive databases.

[fivemack]

NGC1579, the "Northern Trifid Nebula", has a central star "LkH 101" which has a K-B colour index of about fifteen: a million times brighter in 2.2um IR than in the blue.

Quite a good way to see things that are going to be interesting in the IR is to pick fuzzy blobs which seem to be surrounded by a lower star density in the DSS image - this is usually because a dust cloud is obscuring stars behind, and dust clouds are often transparent in the near-IR and brightly emitting in far-IR

[fivemack]

NGC1333 is another area of star formation (including a reflection nebula lit up by a star that has formed), though it doesn't grow quite so excitingly when you switch to the IR