The image to the right was made by the IRAS infrared satellite.
Notice that the W51 nebula is bright in IR even though it cannot
be seen in the visible spectrum.
Compare the IR photograph of W51 with the IR photographs of M17,
the Ring Nebula, and the galaxy M33.
Which object does W51 most resemble?
How would you describe W51 based on these comparisons?
As data are collected, watch where the telescope is pointing and
record infrared measurements the KAO makes. Indicate on the top
photo the locations of each brightness measurement. Use the KAO
guide stars to position your observations.