Messier 17 (Horseshoe Nebula) - Nebula
Messier 17 is a Nebula in the Sagittarius constellation. Messier 17 is situated close to the celestial equator and, as such, it is at least partly visible from both hemispheres in certain times of the year.
Photometric information of Messier 17
The following table lists the magnitude of Messier 17 in different bands of the electomagnetic spectrum (when available), from the B band (445nm wavelength, corresponding to the Blue color), to the V band ( 551nm wavelength, corresponding to Green/Yellow color), to the J, H, K bands (corresponding to 1220nm, 1630nm, 2190nm wavelengths respectively, which are colors not visible to the human eye).
For more information about photometry in astronomy, check the photometric system article on Wikipedia.
Apparent size of Messier 17The following table reports Messier 17 apparent angular size. The green area displayed on top of the DSS2 image of Messier 17 is a visual representation of it.
Digitized Sky Survey image of Messier 17
The image below is a photograph of Messier 17 from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.42x0.42 degrees (25.2x25.2 arcmins).
Celestial coordinates and finder chart of Messier 17
Celestial coordinates for the J2000 equinox of Messier 17 are provided in the following table:
The simplified sky charts below show the position of Messier 17 in the sky. The first chart has a field of view of 60° while the second one has a field of view of 10°.