Deep-Sky Tour
Stare into the Eye of Sauron as you travel around this month’s skies
Tick the box when you’ve seen each one
1 M106
Messier 106 is an intermediate spiral galaxy, a type that shows structure between that exhibited by barred and unbarred spirals. It has a bright active core that also classifies it as a Type 2 Seyfert galaxy. M106 has an apparent magnitude of +9.1 making it a good target for smaller instruments. It lies 6.5° northwest of Chara (Beta (`) Canum Venaticorum). The bright core stands out well for most apertures and appears mottled in a 150mm instrument. Using a large telescope you’ll be able to see M106’s inner core with its stellar nucleus, surrounded by two wide regions representing the galaxy’s arms. SEEN IT
2 NGC 4490
Our next object is NGC 4490, another example of a barredspiral galaxy. It’s located in Canes Venatici and found by extending the line from Cor Caroli (Alpha (_) Canum Venaticorum) through Chara (Beta (`) Canum Venaticorum) by 1/10th. Here you should see mag. +9.8, NGC 4490 and its interacting partner galaxy, mag. +12.0 NGC 4485, 3.5 arcminutes away. Through a 150mm telescope they have the appearance of a small diffuse patch next to a larger diffuse patch. Their apparent size grows through larger instruments with a 250mm scope showing them touching. NGC 4485 appears circular while NGC 4490 has an elongated appearance with more structure. A number of brighter knots can be seen, especially close to the region where both galaxies appear to touch. SEEN IT
3 NGC 4449
Heading 2.5° north from NGC 4490 brings you to the bright, irregular galaxy NGC 4449. This is a member of the Canes Venatici I group of galaxies, located 12 million lightyears away and a relatively close neighbour of the Local Group of Galaxies of which the Milky Way is a member. Parallels have been made between NGC 4449 and the Milky Way’s own satellite galaxy, the Large Magellanic Cloud (LMC). A 150mm telescope shows this mag. +9.4 galaxy easily, but larger instruments are required to pull out detail such as its northeast-southwest elongation and non-uniform brightness. Brighter patches may also be seen near the core. A 300mm telescope brings the hint of a curving arm arching in a northwest direction from the main body of the galaxy. SEEN IT
4 NGC 4151
NGC 4151, ‘The Eye of Sauron’, is an intermediate spiral Seyfert galaxy, characterised by a highly luminous, active nucleus. The driving power behind this bright nucleus is thought to be a supermassive black hole or perhaps a pair of black holes, although there is still uncertainty about the latter. It lies approximately 5.5° southwest of NGC 4449 – roughly the same apparent distance between Chara and Cor Caroli. Smaller apertures show this mag. +10.4 galaxy as a star-like dot surrounded by a faint glow. Larger instruments will show the central core offset northeast of the glow’s centre. The Eye of Sauron nickname refers to its appearance in images taken through the Hubble Space Telescope. SEEN IT
5 NGC 4244
NGC 4244 sits 2.5° southeast of NGC 4151 and 2° southwest of mag. +5.0, 6 Canum Venaticorum. It’s a mag. +10 edge-on spiral galaxy with the appearance of a thin ‘needle’ of light against the background sky. A 150mm telescope shows this incredibly thin needle well. It appears 10x1 arcminutes with a delicate inner core, slightly brighter than the main ‘needle’. Increasing aperture serves to further emphasise the sharpness of the needle. A 300mm telescope expands the apparent size to 15x1.5 arcminutes. Non-uniformity also begins to appear, dividing its length into sections. The overriding impression from looking at NGC 4244 throught the eyepiece is how sharp both ends of its elongated shape actually appear. SEEN IT
6 NGC 4214
Our final target is the irregular galaxy NGC 4214. Locate it by extending a line from Chara through 6 Canum Venuaticorum for 1.2x that distance again. This is a relatively bright mag. +9.7 galaxy that presents a circular glow approximately 1.5 arcminutes across through a 150mm instrument. As NGC 4449 was compared with the LMC, so NGC 4214 is often compared to the Small Magellanic Cloud, albeit as a larger and brighter version. The galaxy contains several huge HII regions at its centre where star formation is occurring. A 250mm scope shows the galaxy to have irregular shape with a small, diffuse but bright spot at its centre. A 300mm scope shows the central region to be broad and elongated. SEEN IT