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Sky delights: a horse with wings.

Who among us is not so familiar with the yet far-northern Pegasus constellation with its very clear square shape and, as a bonus, also appears fairly large. The constellation is very popular, especially with amateur astronomers who observe the depth of its deep-sky objects. To search this large constellation can be done just for fun, but it takes care and determination to study it thoroughly.

Of course, we can get going right away with perhaps one of the most beautiful objects, Messier 15, which can be found located proudly at the horse's muzzle, almost as if it were a delicacy being offered to it.

The globular cluster NGC 7078 (M15) stands out amazingly clearly against the background star field situated only 3 degrees west of the magnitude 2.3 epsilon Pegasi. M15 was discovered by Jean-Dominique Maraldi in September 1746. It is large and bright and displays many faint stars that almost give a three-dimensional impression. What strikes one is the very bright core that almost works itself up to an inner pin-prick core. Many faint stars in strings on the periphery intermingle with one another. It is objects like this that make it worth all the effort to seek out and discover some of the secrets it offers.

A very faint planetary nebula, NGC 7094, can be spotted (if your eyesight is very sharp and that through an amateur telescope) less than 2 degrees further north-east. It has all the qualities of only a faint out-of-focus star, small in size and covered in haziness. It's not at all easy to pick out these faint, small objects among similar-looking stars.

A delicate star grouping is situated midway between epsilon and magnitude 3.3 zeta Pegasi. The galaxy IC 5160 is only 6' north of the lovely open cluster NGC 7193. The sprinkling of a dozen faint stars is situated in an east-west direction. It could well be that the grouping and galaxy at the time of documenting could have been mixed up in the line of things.

Pegasus also has in its midst some very unusual objects. One such is GSO2237+0305, a full 8 billion light years away from us in the far southern corner of the constellation, but it is probably better known as Einstein's Cross or as Huchra's Lens. A Hubble deep picture shows four images of a very distant quasar which has been multiple-imaged by a relatively nearby massive foreground object acting as a gravitational lens. The concept is difficult to understand, but this is in fact the edge of space and time. Rather do not even try to trace it, but you can admire the spot.

The galaxies NGC 7360, 7367, 7373 and 7376 are situated less than a degree to the east of the object. My best attempt at observing the galaxy with a magnitude of around 16 was the spotting of a faint double star of 10 magnitude about 8 arc minutes to the east. There are also three magnitude 9 stars in a string towards the south-west.

There is more to tell about Pegasus the Winged Horse constellation, with another object you might almost certainly not have seen which revolves around the star HD 209458. But if you wish to see the star it is only a degree north-east of the galaxy NGC 7177 and just west of a very red M1 magnitude 6.3 star. A planet has been discovered, now known as HD 209458b, around this star, surrounding it with controversy as it is not known whether it is a planet or a comet or both.

A grouping of stars, standing out clearly against background the star field and easy to find. Further north on the way to iota Pegasi is the star 28 Pegasi just east of this star grouping. About a dozen various-magnitude stars covered in yellow, white and orange jackets, quite outstanding in combination with the magnitude 6.6 super-white 28 Pegasi, form this group. So it is appropriate to call this cluster of stars the 28 Peg Group.

The Amastro Forum is a group of deep-sky amateurs who search the starry field for groups of stars standing out against the background stars. Not only is it a break from searching faint objects, but it is also a daunting task to spot some of them. Then, if recognised, such objects are named after the discoverer. One such asterism, was discovered by Dana Patchick in 1980 and named by his friend Steve Kufeld as Asterism Minor, but the correct indicated nr is Patchick 100. This nice bright group can be found halfway between alpha and beta Pegasi on the Pegasus square's border line with the stars 4.5 tau, 3.5 mu and 3.9 lamda Pegasi in the near surroundings. It is a loose grouping easily seen through binoculars which appropriate displays perhaps a minor winged horse.

Another grouping also discovered by a well-known Amastro member is Bruno Sampaio Alessi. This grouping is situated close to the south-eastern border with Pisces. Alessi had the ability to search out nice tight grouping, most of the time outstanding against the star field. The mostly yellow and orange stars form a concave shape towards the west named for its brightest star, the HD222454 Group, situated just north of the dark nebula LBN 434.

Only three of the four bright stars popularly known as the Square of Pegasus are part and parcel of the constellation. The north-eastern corner star is alpha Andromedae situated virtually on the border line of the two constellations. It would be nice if Pegasus could claim all four corner stars for its constellation.

Perhaps the best known group of galaxies situated very close to the northern border with Lacerta is NGC 7320 and its members. Edouard JeanMarie Stephan (31 August 1837-31 December 1923) was a French astronomer who discovered this group, now known as Stephan's Quintet (Arp 319), but at the time was not aware of its nature, which is 300 million light years away from us.

This tight group is a challenge to select, so one needs time, dark skies, a relatively large telescope and a lot of patience, and perhaps confidence too. But to study groups like this is well worth the effort and very satisfying when bagging some of these faint galaxies. The largest of the group is NGC 7320, which could be a foreground galaxy of the group. The galaxy is situated on the south-eastern edge of the group and appears as a soft oval haze with a slightly brighter core and a magnitude 14 star superimposed on its south-eastern edge. With averted vision, a soft elongated faint nebula roughly east-west opposite and to the north-west marks the combined interacting light of galaxies NGC 7318A and NGC 7318. With higher power the nebula, split by two bright star-like points, indicated the nuclei of these two galaxies. With care and concentration, NGC 7319 shows up as a haze with a low surface brightness just north of NGC 7320. Hanging on the south-western edge of the group, NGC 7317 has the appearance of two fuzzy stars thanks to a magnitude 13 star at the north-western edge just 16" from the nucleus. The entire group is crammed into a circle of less than 4 arc minutes. The odd-one-out member is NGC 7320c, which can be spotted a few arc minutes off to the northeast of this tight group. It is the most crowded of all the Hickson compact group of galaxies, and it is unbelievable that all of them will fit into our Milky Way galaxy. With patience one can be rewarded with a successful attempt at viewing the Quintet. "A huge intergalactic shock wave shown by the magnificent green arc in the Hubble picture is the effect produced by one galaxy falling into another at millions of miles per hour. As NGC 7318A collides with NGC 7318B, gas spreads throughout the cluster, atoms of hydrogen are heated in the shock wave, producing the green glow. The molecular hydrogen is one of the most turbulent forms of molecular hydrogen ever seen. This phenomenon was discovered by an international team of scientists of the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg. Germany. Most notable is the fact that this collision can help provide a view into what happened in the early universe 10 billion years ago when it formed."

If this sounds like too much of a challenge and one that you do not feel like taking on with strength and admiration, then there is another group of galaxies just half a degree further north, known as the Deer Lick Group. American amateur astronomer Tom Lorenzin bestowed the common name on this galaxy group NGC 7331 to honour the Deer Lick Gap, which lies in the mountains of North Carolina. Another possibility is that it is because numerous small galaxies hover nearby like deer clustered around a salt lake. To describe the group in more detail: NGC 7331 is a large angled spiral, elongation approximately north-south and relatively easy to glimpse through an ordinary amateur telescope. Closer investigation reveals faint knotted areas on the surface with a much brighter oval-shaped nucleus. On the hazy north-western tip of the galaxy two faint stars can be glimpsed with careful observation and can easily be mistaken for possible supernova explosions. NGC 7335 is situated close on the eastern rim of NGC 7331. Only 2 arc minutes further north the galaxy NGC 7336 could at best be only another fleck of light. Two more galaxies, NGC 7337 and NGC 7340, situated slightly further east, complete this group of five galaxies.

A surprise was discovered in the star field between Stephan's Quintet and The Deer Lick group of galaxies. Stephan O'Meara spotted a tight string of stars in an east-west direction almost halfway between these two compact groups of galaxies. He characterized this handful of stars as "fleas" surrounding the group of deer!

In mythology Pegasus was the son of Neptune and Medusa who at his father's command leapt into the sea. He seems, however to have come back to earth again with wings. So, fly with this sky-figure horse through the depths of the universe and explore these fascinating objects, and admire once again the brilliant brain of Mr Einstein That will keep you busy for a long time!

OBJECT                           TYPE               RA

NGC 7094                         Planetary Nebula   21h36m.8
NGC 7078 Messier 15              Globular Cluster   21h29m.8
NGC 7193                         Open Cluster       22h02m.9
HD 209458 Group                  Open Cluster       22h03m.2
28 Pegasi Group                  Open Cluster       22h10m.5
GSO2237+0305 Einstein's Cross    Galaxy             22h40m.5
NGC 7317                         Galaxy             22h35m.9
NGC 7318                         Galaxy             22h35m.9
NGC 7318A                        Galaxy             22h36m.0
NGC 7319                         Galaxy             22h36m.1
NGC 7320                         Galaxy             22h36m.1
NGC 7331                         Galaxies           22h37m.1
NGC 7335                                            22h37m.3
NGC 7336,                                           22h37m.2
NGC 7337                                            22h37m.4
NGC 7340                                            22h37m.6
Stephan's Group                  Asterism           23h37m.4
HD 222454 Group                  Open Cluster       23h40m.7

OBJECT                           DEC                  MAG

NGC 7094                         +12[degrees]47'.2"
NGC 7078 Messier 15              +12[degrees]10'.2"   6.2
NGC 7193                         +10[degrees]48'.3"   10.2
HD 209458 Group                  +18[degrees]53'.5"   7.6
28 Pegasi Group                  +21[degrees]03'.0"   9
GSO2237+0305 Einstein's Cross    +03[degrees]21'.5"   16.5
NGC 7317                         +33[degrees]56'.8"   13.6
NGC 7318                         +33[degrees]57'.8"   13.4
NGC 7318A                        +33[degrees]57'.5"   13.3
NGC 7319                         +33[degrees]58'.7"   13
NGC 7320                         +33[degrees]57'.1"   12.6
NGC 7331                         +34[degrees]25'.3"   9.5
NGC 7335                         +34[degrees]27'.3"   13.3
NGC 7336,                        +34[degrees]29'.0"   14.7
NGC 7337                         +34[degrees]22'.0"   14.4
NGC 7340                         +34[degrees]25'.8"   13.7
Stephan's Group                  +34[degrees]08'.6"   13
HD 222454 Group                  -07[degrees]57'.4"   6.8

OBJECT                           SIZE

NGC 7094                         158"
NGC 7078 Messier 15              12.3'
NGC 7193                         12'
HD 209458 Group                  *
28 Pegasi Group                  14'
GSO2237+0305 Einstein's Cross    2'
NGC 7317                         0.5'x0.5'
NGC 7318                         0.9'x0.9'
NGC 7318A                        1.7'x1.2'
NGC 7319                         1.5'x1.1'
NGC 7320                         1.7'x0.9'
NGC 7331                         10.5'x3.7'
NGC 7335                         1.3'x0.6'
NGC 7336,                        0.5'x0.4'
NGC 7337                         1.1'x0.9'
NGC 7340                         0.9'x0.6'
Stephan's Group                  1.5'
HD 222454 Group                  14'x4'
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Article Details
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Author:Streicher, Magda
Publication:Monthly Notes of the Astronomical Society of Southern Africa
Article Type:Column
Geographic Code:1USA
Date:Oct 1, 2014
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