Solar System

(The Lyre)

Lyra is a parallelogram shaped constellation that is easy to find due to the dazzling light of its brightest star Vega. This impressive star is so luminous that it is the fifth brightest star in the sky! It is also part of the Summer Triangle asterism along with Deneb in Cygnus and Altair in Aquila.

Without a shadow of a doubt, the shining jewel of Lyra is the Ring Nebula, a resplendent planetary nebula that is the favourite of many observers.

  Ring Nebula   M56:
    A sparsely populated globular cluster, the light of this 8th magnitude globular cluster takes 33 000 years to reach us. A bright concentrated core is absent from M56 therefore reducing its allure although it is still a fairly satisfying sight.
Ring Nebula (M57):

The Ring Nebula is a bright and intensely colourful planetary nebula that is deservedly famous. Photographs with exposures taken through H-alpha filters reveal the extensive gossamer of an outer halo. Curiously, the halo seems to consist of two parts, a small bright ring with a more large diffuse part that appears to lie behind the brighter part. This could be evidence that the nebula is definitely bi-polar in shape with a gaseous halo encircling both poles.

The inner part of the ring and the edges of the central pool of turquoise light look brighter than the surrounding parts. This is caused by two different events that result in the same visual appearance. The brightening in the ring is due to one of the concentric subshells exhibiting the phenomenon of limb brightening. The inner part is bright at the edges due to the ionized winds in the inner halo having a brightened rim.

One of the most famous planetary nebulae, the Ring Nebula is a gleaming gem found between the two stars at the base of the parallelogram, Sulaphat (Gamma Lyrae) and Sheliak (Beta Lyrae). A medium sized scope is the prerequisite needed to see the wispy ring that is tinged with a hint of smokiness.

What is surprising about the Ring Nebula is its faint magnitude of 8.8, it still appears bright due to its small size. The distance of 1600 light years is responsible for its small apparent size, if it was 1000 light years closer it would appear larger.

The region within the ring contains oxygen and nitrogen that is ionized by the ultraviolet radiation released by the intensely blue central star that is challenging to see as it is magnitude 15. Ionised hydrogen and helium are responsible for the brownish red colourisation of the outer ring.

The calm serenity of the Ring Nebula is quite deceptive and belies the advanced elaborate structure. In reality, the central part is encompassed by a series of concentric rings and an inner halo that has a brightened limb. It is currently believed that the Ring Nebula is actually a bi-polar nebula with the end facing us.

Image copyright A. Block/R. Jay GaBany
    NGC 6765:

Discovered to be a planetary nebula by Rudolph Minkowski in 1946, this 13th magnitude obscurity is virtually unknown compared to the Ring Nebula. It consists of two polar jets that are encapsulated by an irregular outer shell. If the orientation of this planetary nebula was identical to M57, it would probably have a similar appearance albeit with a smaller size and a more elusive outer halo.


The rest of the constellation pages are unavailable as they haven't been completed yet.