Whats in your Sky this Autumn?

One of the most fascinating aspects of the science of astronomy is the concept of distance. Everything in the night sky is so incredibly remote! Even the closest star to our solar system, the Alpha Centauri triple-star system, is 25 trillion miles away. The thousands of other stars that we see every clear night with the naked eye, as well as the millions of stars visible through telescopes and binoculars, are farther still!

As mentioned there many objects that require a small telescope to see but some don't. Go out at the moment if we have clear skies and simply look overhead at the Milky Way. Simply marvel at its incredible beauty. In the constellation of Cygnus is wanders through but when it comes to the horizon through Sagittarius it positively glows brightly.

1. Dark skies - A must, no moonlight, no city lights, no headlights, no streetlights

2. At least one eyeball - no telescopes, no binoculars, (just eyeglasses if you're near sighted)

3. A little bit of timing - late summer or Autumn evenings are best.

4.The Andromeda galaxy (or M31) can be seen as a fuzzy patch in the constellation of Andromeda (again only if it is very dark out).

Photo Ethan E Allen

It extends through the constellations Perseus, Cassiopeia, and Cepheus. In the region of the Northern Cross it divides into two streams: the western stream, which is bright as it passes through the Northern Cross, fades near Ophiuchus, or the Serpent Bearer, because of dense dust clouds, and appears again in Scorpio; and the eastern stream, which grows brighter as it passes southward through Scutum and Sagittarius. The brightest part of the Milky Way extends from Scutum to Scorpio, through Sagittarius. The center is in the direction of Sagittarius and is about 28,000 light years from the Sun.

Much of the Milky Way is invisible to us because we have to look through the plane of its disk – a lot of the Milky Way is on the other side of the galaxy, and there is so much dust and so many bright stars closer to us that we can't see the stars behind all of this matter.

Of the 5,000 to 8,000 stars in the Milky way visible to the human eye from Earth, one can usually only see about 2,500 at a time. In fact, the few thousand stars we can see of the Milky Way with our naked eye are only about 0.000003% of the 200-400 billion stars that inhabit the spiral!. 

To see a picture of the entire Milky Way from the Earth at once, you have to create a mosaic of photographs taken at different times. This is because the Milky Way moves overhead at night with the rotation of the Earth, so can't be viewed all at once from one spot.

Many panoramas of our galaxy can be found on the web. Scattered around the Milky Way are fascinating sights called deep-sky objects, a general catch-all phrase that includes a wide variety of celestial denizens.

These include huge clouds of gas and dust called nebulas, which can be divided further into emission nebulas, reflection nebulas, and planetary nebulas. Star clusters form a second grouping of deep-sky objects. Open star clusters are made up of anywhere from a dozen to several hundred young, chiefly blue-white stars. Most of these stellar swarms lie within the spiral arms of our own galaxy, the Milky Way. Globular star clusters, made up of some of the oldest stars known, Each contains between 100,000 and a million constituents.

Messier and NGC: A Lifetime of Treasures

Deep-sky objects are usually designated by catalog numbers, such as M42 or NGC 869. The Messier catalog, is the most famous listing of deep-sky objects. Created by Charles Messier, an 18th-century comet hunter, this catalog consists of 109 of the finest objects the sky has to offer. Finding all of the "M" objects is a great introduction into deep-sky observing, since most are bright enough to be seen even through modest equipment. The New General Catalogue of Nebulae and Clusters, or NGC, was compiled in the 1880's by John Dreyer and based on observations by the father-son team of William and John Herschel. More than 7,800 objects are listed in the NGC, certainly more than enough to occupy the owners of even the largest backyard telescopes for a lifetime. Finding deep-sky objects through binoculars and backyard telescopes andd using a starmap is one of the most exhilarating, challenging, and thought-provoking aspects of the hobby of astronomy.

Some of my Autumn Favourites

Triangulum Galaxy M33

A great galaxy in the autumn sky is the face on spiral galaxy M33 in Triangulum. M33 is a large, diffuse galaxy, but it is very dim due to its face-on orientation, and requires a good, steady night for best views. Nevertheless, it can easily be found with binoculars as a bright fuzzy patch below M31. M31, M33 and our own galaxy, the Milky Way, are part of a cluster of galaxies called the Local Group of Galaxies. I have seen it with the naked eye.

To Find M33: First find M31, the Great Galaxy in Andromeda. Start from 3rd base of the Great Square of Pegasus. Then, simply count stars, 1, 2 to Beta Andromeda (away from the great square), then up (west) 1, 2 stars, and there it is! Once you have found M-31, M-33 is on the exact opposite side of Beta And, and an equal amount below the star. M33 is not a naked eye object except in perfectly dark conditions.

Perseus The Double Cluster

A different type of cluster, in fact, two clusters, are the open clusters NGC 869 & 884 in Perseus. The Double Cluster in Perseus is one of the finest sights in the sky.

These two open clusters are both large and bright, and fall in the same low power field of view. NGC 869 is the brighter and more concentrated of the two, and is dominated by two bright orange stars near its center. NGC 884 is slightly larger, and has many more orange-red stars. Both clusters contain over 100 stars each.

 Aquarius

The four constellations of Aquila, Aquarius, Capricornus, and Delphinus lie relatively close to each other along the southern horizon in a region of the sky which is almost devoid of bright showpiece deep sky objects. Aquarius and Capricornus lie away from the main body of the Milky Way, and mostly contain faint galaxies with only a few star clusters and nebulae. Aquila and Delphinus, on the other hand, lie right along the Milky Way and contain some fine examples of planetary and dark nebulae. Even though there are only four Messier objects in this entire region, there are still enough deep sky targets to keep an astronomer busy on an autumn evening.

NGC 7293, The Helix Nebula in Aquarius, while not a Messier object, is of special note. Lying at a distance of only about 325 light years, this planetary nebula is probably the closest planetary nebula to us in space. Its light is spread out over about 15', so its surface brightness is rather low. Easily seen in binoculars as a greyish circle of light, this object absolutely jumps out of the eyepiece of your telescope when observed with an O-III filter.

I have only observed this object once but was easily found in my 7x50 Binoculars and looked huge in the eyepiece of my 200mm Meade telescope.

One object of special note in Pegasus, however, is not a galaxy. It is the globular cluster, M15. M-15 is a nice, bright globular cluster that is easily seen in the viewfinder or binoculars. It handles magnification well, showing a tight mass of stars 8' in diameter with a much brighter central region. Individual stars are resolved around the edges and across its face but not quite to the center. This cluster can be found by starting at Alpha Pegasi, the opposite corner of the Great Square of Pegasus from Andromeda, and then following the chain of stars depicting the head of the Flying Horse. M15 will be right at the end of the this chain of stars, situated like a small fly buzzing around the nose of the flying horse. One of the many Globular clusters of the Autumn sky namely M13, M22,M4. M5. M71 & M2

For a free open source planetarium for your computer that shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope, click on our Astro-links section as click again on Stellaruim.

King of the Planets

The King of the Planets is climbing in the east as the sky starts to darken after sunset. If you haven’t looked at Jupiter in a while, the Red Spot is actually red again, and the normally-brown South Equatorial Belt has faded almost completely. This is a big switch from the past year or two, when the “Red” Spot has mostly been visible as a white notch in the SEB.

The magnitude –2.8 and dominating the southern evening sky is the Planet Jupiter. In constellation of Pisces, one of the watery groups in an area of sky known as the Celestial Sea. Jupiter rises at 22:00UT at the beginning of August and by 20:00UT at the end of the month.During September will be only 3.9539 AU from Earth with an angular diameter of 49.8 arcseconds and magnitude -2.9. That’s slightly nearer than the 2011 closest approach. Still by any accounts is a wonderful sight through any small telescope with its four brightest "Galilean Moons" easily visible.

Bottle-green Uranus is in the same area too. This recent image of Uranus was shot through a  Meade 8" SCT like my own. Uranus' green coloration (due to its methane atmosphere absorbing other colors) is quite clear and the view is representative of what can be seen of Uranus through a telescope.

The magnitude 5.8 planet lies in the same low-power binocular field as Jupiter all month Uranus isn’t a popular observing destination, unlike Jupiter, you cant just swing your telescope to it.

At a distance of 2.4 billion miles, six times the distance of Jupiter, thats twice the distance from the Earth to Saturn and being only four times the size of Earth, it give Uranus a diminutive size in telescopes, just 4 arc seconds across. Visually it is not very striking compared to the likes of Saturn or Jupiter, but is visible in even small telescopes, they will show it as a tiny bland blue-green disk. Uranus is a very remote planet to look at, there is just a certain fascination in viewing it yearly as it moves gracefully against the background stars. Uranus is a naked eye object using adverted vision from a dark site. 

For a free and complete guide to whats to see in the night sky download the "2010 Guide to the Sky", this fascinating 36 page document in produced by well known Irish astronomer John Flannery and is a must for any amateur astronomer. down load it Here

Iridium Flares

These are a wonderful set of satellites that I have watched over the past ten years. After Comet HALE BOPP and the formation of the Galway Club my interst in astronomy kick started again, after buying a telescope and spending many nights out observing I started noticing  these extremely bright satellites, but these were no ordinary satellittes. The would be moving along and then all of a sudden energise in brightness to about 40 times that of Venus similar to a First Quarter Moon for several seconds and the fade away. A fantastic sight and whats even more amazing is that you can find out when and in what part of the sky to see them. You do not need to know the constellations just face the direction given, you can't miss them. Also the lower the magnitude, the brighter. Usually -8 is the best we can see.

The Iridium communication satellites have a peculiar shape with three polished door-sized antennas, 120° apart and at 40° angles with the main bus. The forward antenna faces the direction the satellite is traveling.

Occasionally, an antenna reflects sunlight directly down at Earth, creating a predictable and quickly moving illuminated spot on the surface below of about 10 km diameter. To an observer this looks like a bright flash, or flare in the sky, with a duration of a few seconds.

Ranging up to -8 magnitude (rarely to a brilliant -9.5), some of the flares are so bright that they can be seen at daytime; but they are most impressive at night. This flashing has been some annoyance to astronomers, as the flares occasionally disturb observations and can damage sensitive equipment. When not flaring, the satellites are often visible crossing the night sky at a typical magnitude of 6, similar to a dim star.

Viewing Satellite Flares

Looking for satellites whilst skygazing, or satellite spotting, is a hobby for many people. While satellites may be seen by chance, there is a  websites HERE which provide location specific information as to when and where in the sky a satellite flare may be seen.

Clear Skies!

Ronan Newman