The Hidden Galaxy
Equipment :
SkyWatcher EQ-6R Pro GoTo
Skywatcher Equinox 120/900 with 0,85x Flattener
Guiding telescope:
Skywatcher ED50 APO
Guiding Camera:
ZWO ASI290 MM Mini
Image Details
IC 342
Exp. data :
12 x 900s
Image capture date  :
Observing Site
Nagybörzsöny - Hungary
E18°49'29" ; N47°55'57"
Short Description
Caldwell 5, also known as IC 342, is a spiral galaxy located approximately 11 million light-years from Earth. This sparkling, face-on view of the center of the galaxy displays intertwined tendrils of glowing, rosy dust in spectacular arms that wrap around a brilliant blue core of hot gas and stars. This core is a specific type of region called an H II nucleus — an area of atomic hydrogen that has become ionized. Such regions are energetic birthplaces of stars where thousands of stars can form over a couple million years. Each young, extremely hot, blue star emits ultraviolet light, further ionizing the surrounding hydrogen. Despite its 8.4 magnitude, Caldwell 5 is very difficult to find in the sky. The galaxy appears near the equator of the Milky Way’s pearly disk, which is crowded with thick cosmic gas, dark dust and glowing stars that all obscure our view. Therefore, in order to distinguish the intricacies of Caldwell 5 through a telescope, astronomers must peer through light-years of space chock-full of visual hindrances. This has earned Caldwell 5 the nickname of the Hidden Galaxy. Were it not obscured by so much interstellar matter, the Hidden Galaxy would be one of the brightest galaxies in our sky. A relatively close galaxy, it is roughly 50,000 light-years across and billions of years old. Its face-on alignment makes it a prime target for possible supernova sightings, but so far, scientists have seen none. Caldwell 5 was discovered in the early 1890s by William Frederick Denning, a British amateur astronomer who had practically no formal scientific training yet still managed to achieve a great amount of success in astronomy (discovering several comets, publishing more than a thousand scholarly articles, and winning the Gold Medal of the Royal Astronomical Society). The best time of year to look for Caldwell 5, which is located in the constellation Camelopardalis, is during late autumn and early winter in the Northern Hemisphere. In the Southern Hemisphere, only those located close to the equator will have a chance to spot it low in the northern sky during late spring or early summer. True to its name, the Hidden Galaxy can be difficult to find, especially if your sky is light polluted or even slightly cloudy or hazy. Wait for the clearest of nights and travel away from city lights to search for it with a telescope. In 1935, Harlow Shapley found that it was wider than the full moon, and by angular size the third-largest spiral galaxy then known, smaller only than the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). (Modern estimates are more conservative, giving the apparent size as one-half to two-thirds the diameter of the full moon). It has an H II nucleus. The galaxy has a diameter of 75 000 light-years.