This image captured by the Hubble Space Telescope highlights the galaxy SDSS J103512.07+461412.2 in the constellation Ursa Major. The galaxy takes its name from the Sloan Digital Sky Survey (SDSS), which has cataloged hundreds of millions of astronomical entities since its inception in 2000. Image source: ESA/Hubble and NASA, R. Tully
This Hubble image of the week contains the medullary galaxy named SDSSJ103512.07+461412.2. In the center of this image, you can see a scattered galaxy composed of dust and stars, with a denser and brighter core. SDSSJ103512.07+461412.2 is located 23 million light-years away from Earth in the constellation Ursa Major. The Sloan Digital Sky Survey (SDSS) is a large-scale sky survey launched in 2000 to observe and catalog a large number of astronomical objects. To date, it has recorded hundreds of millions of celestial objects.
In the early days of astronomical catalogues, astronomers painstakingly recorded individual objects one by one. For example, the Messier catalog contains only 110 objects and was identified by astronomer Charles Messier because these objects hampered his efforts to capture comets. Since the Messier catalog is very limited, we only need to refer to these objects as M1 to M110. In contrast, when it comes to large-scale sky surveys like SDSS, when large amounts of data need to be processed automatically, the names assigned to celestial objects need to be longer and more informative.
To this end, each SDSS object is named according to the following format: "SDSSJ", followed by right ascension (RA) and declination (Dec). Right ascension (RA) and declination (Dec) define the position of a celestial body in the night sky. Right ascension is equivalent to longitude on Earth, while declination is equivalent to latitude. More precisely, RA measures the longitudinal distance of a celestial body from the intersection of the celestial equator (the midpoint between the north and south poles) and the ecliptic (the plane of the Earth's orbit around the sun).
The entire night sky is then cut into 24 segments, called "hours," measured eastward from this starting point (designated as zero hour). This means that RA can be expressed in "hours", "minutes" and "seconds". Latitude is the angle north or south of the celestial equator, expressed in degrees.
Therefore, the name SDSSJ103512.07+461412.2 just tells us that this galaxy is located 10 hours, 35 minutes and 12 seconds east of the zero hour point of the celestial equator and a little more than 46 degrees north of the celestial equator. Therefore, this lengthy name is actually an identifier and a detailed location.