Constellations - Equuleus and Delphinus

Constellations - Equuleus and Delphinus


Delphinus, the Dolphin (top constellation on the chart) was described by the 2nd Century astronomer Ptolemy in his original 48 constellations. It is a small constellation ranking 69th out of the 88 constellations.

Equuleus, the Little Horse (lower constellation on the chart) is a small and relatively faint constellation found bordered by Aquila, Aquarius and Pegasus. It was included in the original 48 constellations described by Ptolemy. It is the second smallest constellation. It contains some binary star systems and a triple star system (5.4 on the chart).


Delphinus was the dolphin that Poseidon sent out to find Amphitrite, a sea nymph that he wanted to marry. Delphinus was able to convince the sea nymph to marry Poseidon and took her back to his palace. As a thank you Delphinus was placed amongst the stars in the silvery river of the Milky Way.

Equuleus is thought to represent the foal of the winged horse Pegasus. The foal's name was Celeris and was given to Castor as a gift by Mercury. Celeris was hit by Neptune's trident during a contest with Athena to decide who was the best.

Take the Tour:

Number Object Description Magnitude Surface Brightness
1 C42 Globular Cluster 10.5 13
2 C47 Globular Cluster 8.9 Unknown
3 M15 Globular Cluster 6.3 11
4 M2 Globular Cluster 6.5 11

Each image is the size of a full moon for size comparison.



Caldwell 42, or NGC 7006 is a globular cluster. It appears very small in the telescope because it is found so far away. This globular cluster is found on the outskirts of the Milky Way, almost 135,000 light years away. Don't confuse it with a faint star or you might miss it.



Caldwell 47, or NGC 6934 is a globular cluster. It was discovered by Herschel in Sept 1785. It is also found a very distant 52,000 light years away. However, it is brighter and larger than C42. 

M15, the Pegasus Cluster:


Messier 15 was discovered by Maraldi in September 1746. It is located about 33,000 light years away. This globular cluster is easily seen in binoculars. It is considered to be one of the oldest and densest clusters in our galaxy. The central core is so dense that it may contain a black hole. This was the first globular cluster to have a planetary nebula discovered within it. The nebula is visible to large amateur telescopes. The cluster also contains a large number of variable stars and pulsars, including a binary pulsar system.



Messier 2 is a globular cluster found 33,000 light years away and is one of the largest globular clusters known. It was discovered by Maraldi in September 1746. It is an easily observed cluster even from urban locations and contains around 150,000 stars. 

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