Top 10 Night Sky Objects for Astronomy Beginners

The Big Dipper is probably the best known asterism for stargazers in the Northern hemisphere. Big Dipper consists of seven stars and belongs to the constellation Ursa Major, or Great Bear. It is easy to find and its serves as guidepost to Polaris. Find the brightest two stars at the outer bowl edge, Dubhe and Merak. Take 5 times their distance and you reach Polaris, the Northern Star.

Big Dipper holds some surprises that are revealed at closer observation. Point your telescope at the handle bend and what you see are not one but two stars. The brighter one is Mizar, the dimmer star is Alcor. They are also known as “Horse and Rider”. People with good eyesight can distinguish these two stars with bare eyes. If the seeing conditions are good, choose high magnification and take a closer look at Mizar. You will see that Mizar itself has another close companion star.  The image above shows an actual photo of Mizar A, his close companion Mizar B and Alcor (click at the image to open a larger scale version).

Click here for a star map of Ursa Major.

Facts:
The Mizar – Alcor system consists of even more stars that are however too faint for small telescopes. Four stars belong to the local Mizar system and the Alcor system consists of two. New research has revealed that both systems are gravitationally linked, making Mizar & Alcor a true 6-star system.	Constellation: Ursa Major, UMa Magnitude (Mizar/Alcor): 2.2 /4.0 Separation: 11.8′ Distance: 83 light years Mass (Mizar/Alcor): 7.7 /2 x Sun, Diameter: 4.1 / 1.8 x Sun Luminosity: (Mizar/Alcor): 63 / 13 x Sun

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Albireo

In the night sky: late Spring to Fall.

Albireo is the fifth brightest star in the constellation Cygnus (Swan). With naked eye it appears to be single star but a telescope resolves it as double star. Both stars offer a striking color contrast. The brighter star shines in yellow color, the smaller star in blue.

Image credit: Hunter Wilson.

When observing colorful stars, it can be beneficial to do this somewhat out of focus. Since the star disks become larger, colors become more prominent. The reason for this is that a larger number of color receptors in the eyes can collect color information . Play with your focuser and see what works best for you.

Click here for a star map of Cygnus.

Facts:
At this point it is unknown whether the stars are optical doubles or gravitational linked and orbiting each other.The brighter star itself has a very close companion, too close though to be resolved with a telescope.	Constellation: Cygnus, CYG Magnitude: A 3.2, B 5.8 Separation 35″ Distance 390 / 390 light years Mass: 5 / 3.2 x Sun Diameter: 16 / 2.7 x Sun Luminosity: 950 / 120 x Sun

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Orion Nebula (M42)

In the night sky: Winter and Spring.

The Orion Nebula is part of the constellation Orion. This truly beautiful nebula can be found just below Orion’s belt as a part of Orion’s sword. It is one of the brightest nebulae and is visible to the naked eye.

Because M42 is over an arc minute wide use your lowest magnification to ensure it fits in the field of view. The four stars at its center are called “Trapezium”, they energize and ionize surrounding gasses which leads to this beautiful spectacle.  Due to its brightness, the Trapezium stars draw the observers attention, but when scanning the area around them, you will see many smaller stars and layers of ionized gas.

Click here for a star map of Orion.

Facts:
Orion nebula is the closest region of massive star formation to the Earth. It hosts protoplanetary discs and brown dwarfs. New stars and planets are born there right now. The strong radiation emitted by the Trapezium stars is so powerful that young neighbor stars are pushed into the form of an egg.	Constellation: Orion, ORI Magnitude: 4.0 Size: 65’x60′ Distance 1,344 light Years Diameter: 24 light Years Mass: 2,000 x Sun

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Andromeda Galaxy (M31)

In the night sky: Summer, Fall and Winter.

The Andromeda Galaxy belongs to the constellation Andromeda. It is the farthest object that can be seen with bare eyes. It is so large that it will most certainly exceed the field of your telescope view (binoculars have sufficient viewing angle). Nevertheless it is a fascinating moment taking a peek at another galaxy for the first time. The core of Andromeda is very bright and the surrounding areas can be seen nicely.

There are many ways finding the Andromeda Galaxy in the night sky. My favorite is to extend the most pointy part of the Cassiopeia “W” three times.

Click here for star maps of Andromeda and Cassiopeia.

Facts:
The Andromeda Galaxy is a spiral galaxy has an estimated 1 Trillion stars (Milky Way 200 – 400 Billion). Its center comprises a massive black hole. Andromeda Galaxy and the Milky Way are moving towards each other. They will merge in about 4.5 Billion years.	Constellation: Andromeda, AND Magnitude: 3.44 Distance 2.54 Million light years Mass: 1- 1.5 x Milky Way galaxy

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Hercules  Cluster (M13)

In the night sky: Spring, Summer and Fall.

As it’s name already reveals, the Hercules Global Cluster lies in the constellation Hercules.  The Globular Cluster is almost as old as the known universe and offers beautiful view even for small telescopes.

Image Credit: ESA, NASA

It is a bit more challenging to find Hercules Globular Cluster. First we have to find “The Keystone”, four stars of the constellation Hercules that build a trapezoid. M13 lies on the line between Eta Herculis and Zeta Herculis. These are the two stars in “The Keystone” at the side of Arcturus. Move a little bit towards Eta on the Eta-Zeta line and you have found this beautiful globular cluster. If you have difficulties to find “The Keystone”, two bright stars, Vega and Arcturus help. Draw a line from Vega to Arcturus, “The Keystone” is located about one third the distance from Vega.

Click here for a star map of Hercules.

Facts

Despite it’s age, Hercules Globular Cluster has not changed its form much. Pressure of star radiation pushing stars apart and gravity force pulling them together, resulting in an equilibrium. The stable conditions were thought to be beneficial for possible forming of life. In 1974 a radio message was sent to the Hercules Cluster with the large Arecibo radio telescope. The digital message included information about man, earth and the solar system.

Constellation: Hercules, HER Magnitude: 5.8 Distance 25,100 light years Diameter: 168 light years Mass: 600,000 times Sun Age: 14 Billion years

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Double Cluster (NGC 869 & NGC884)

In the night sky: Fall, Winter, Early Spring.

In his classic Field Book of the Stars (1929), William Olcott called the Double Cluster: “One of the finest clusters for a small telescope. The field is simply sown with scintillating stars, and the contrasting colors are very beautiful”. Does this not make anyone thrilled to observe this fine object? What we see are in fact two independent open clusters. They are about 800 light years apart but due to their position in the sky, they fit both in the view of a small telescope.

The Double Cluster belongs to the constellation Perseus. It can be easily found with the help of the constellation Cassiopeia. Just follow the inner leg of the shallow half of the “W” (Cassiopeia Gamma – Delta) about two third of the way to the next bright star, and you will find the Double Cluster.

Click here for star maps of Perseus and Cassiopeia.

Facts:
The Greeks knew about the object as early as 130 BC, but the true nature of it was not discovered not before the telescope was invented. The radiant of the Perseid meteor shower (Aug 12 & 13) is located in the neighborhood of the Double Cluster (SW).	Constellation: Perseus, PER Magnitude: 4.2 Distance (NGC 869): 6,800 light years Distance (NGC 884): 7,600 light years Age (NGC 869): 5.6 Million years Age (NGC 884): 3.2 Million years

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Dumbbell Nebula (M27)

In the night sky: Fall, Winter, Spring

With a magnitude of 7.5 , the Dumbbell Nebula is the faintest object in our Top-10 list. It is however the second largest planetary nebula in the northern sky and can be found relatively easily. The Dumbbell Nebula is located in the constellation Vulpecula, Latin for “Little Fox”. Vulpecula is a very small constellation with faint stars, southwest of Albireo in the constellation Cygnus. My preferred way to find M27 is with the help of the constellation Sagitta, the “Arrow”, just south of it. Its stars are brighter so they are easier to make out. They are shaped like an arrow with feathers (or a triangle  with tip). The Dumbbel Nebula, M27 is pretty exactly north of Sagitta’s tip star, Gamma Saggitae.

Click here for star maps of Vulpecula, Cygnus and Sagitta.

Facts:
M27 is a planetary nebula. This term was coined by early astronomers who thought these nebulae were planets. In fact, they have nothing to do with planets. Planetary nebulae are clouds of material, shed by a star. It glows because it is excited by radiation emitted by a nearby object.	Constellation: Vulpecula, VUL Magnitude: 7.5 Distance 1,360 light years Diameter: 1.44 light years Central star Dia: 0.055 Sun, Mass: 0.56 Sun Age: only 9800 years

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