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Practical: The Autumn Night Sky - Sights to see along the milky way 19-04-2016

A tour of Carina, Vela, Puppis, Canis Major and Columbia

  1. Rob Glassey
    The constelations of the Autumn Milky Way.

    CHART 1: Carina and Vela

    This is the sky around the Diamond Cross and the False Cross. It is a wonderful area to scan with binoculars.

    Carina - The Keel

    Carnia Nebula: The brightest patch of this part of the milky way. Bigger than most telescopic fields of view. Divided by a dark "V" separating the brightest segment from the rest. The brightest star in this bright segment is Eta Carnia, bright orange and a bit fuzzy. At high power in large telescopes the fuzziness resolves into a tiny twin lobed nebula, called the Homonculus (Little man).

    Keyhole Nebula: This is often the name given to the entire Carina nebula, but it actually refers to a keyhole shaped darker patch right beside Eta Carina itself. It's roughly half the height of the bright segment of the Carnia nebula and embedded near the centre.

    Diamond Cluster, NGC 2516: Off then end of the false cross. Visible as a fuzzy patch to the naked eye. Bright, scattered cluster, with several bright orange stars.

    Fireworks Cluster, NGC 3114: Visible to the naked eye as a fuzzy patch between Carina Nebula and the false cross. More stars than the diamond cluster.

    Wishing Well Cluster, NGC 3532: A fuzzy patch on the southern cross side of the Carnia nebula. Stretched out. Many many bight stars, with a bright orange one on the edge.

    Southern Pleiades, IC2602: The Carina nebula end of the diamond cross. One very bright star (Theta Carina) makes the others hard to see naked eye. Binoculars will show the cluster well. Look for the capital sigma shape.

    The Gem Cluster, NGC 3293: Not obvious to the naked eye. Smaller than the previous clusters. Vela side the Carina Nebula, a short distance away. An obvious red star lined up with a yellow and a blue star, with less obvious colour. A nice compact cluster.

    NGC 2808 Globular Cluster: a compact and bright glob. Strongly concentrated core, over a million stars. Possibly a core of a small galaxy absorbed into the milky way due to the unusual range of ages of the stars within the cluster. Compare this glob with NGC3201 in Vela which is must more diffuse, with no strong central concentration.

    NGC 2867 Planetary Nebula: Tiny object, but fairly bright. Magnitude 9. About the half the apparent size of Mars. Not an easy object. Use low power to locate the stars in the field. It looks like another star at low power, but at higher power it become a fuzzy star, while the other stars are sharper. In a large telescope the edges of this nebula are sharply defined. For an easier planetary nebula, look at the 8-Burst Nebula in Vela.

    Double Star Rumker 8: Near the diamond cluster. HIP 40429. Magnitude 5 star with a magnitude 8 star just 4 arc seconds away. ie 5/8-4" A challenging double.

    Double Star Upsilon Carinae: 3/6-5" Easier than Rumker 8, but still a close double with a dim secondary. Visible in 60mm scope. Use at least 100x once you have found the star.

    Variable star S-Carinae: This is a Mira type variable star, named after Mira, first star found of this type. Mira variables have huge changes in brightness over a regular periods of more than 100 days. S-Carinae varies from about mag 9 to mag 5.5 over 150 days. Right now it is about magnitude 7 and is getting brighter. Around June it will reach maximum brightness, and will be brighter than all the other stars around it, except the bright naked eye stars. It will become visible naked eye from a dark location. Take a look now to see the difference over the next two months. Many of the nearby stars are magnitude 6-7, so it will go from being a dim star amongst them, to being the brightest.

    Vela - The sail

    Look for the large triangle formed by the bright stars Regor, Naos and Suhail. This boarders one side of Vela. The other side is marked by half of the False cross.

    Regor / Gamma Velorum: This is am easy, wide spaced quadruple star. The two brightest stars are mag 1.9 and Mag 4.2, 41 arc seconds apart (the full width of Saturn and it rings). The next star forms an equilateral triangle with the first two and is much dimmer, mag 7.3. The fourth is even dimmer, magnitude 9.4 and one step further away from the main pair.

    Regor Cluster NGC 2547: Near Regor. Nice cluster, fairly compact.

    Omicron Velorum: More of a nice bunch of 6 or so bright stars. Nice in binoculars.

    The 8 Burst Planetary Nebula, NGC 3132: Big and bright for a planetary nebula. About the size of Jupiter. The central star is magnitude 10, and is visible in medium size telescopes. The nebula itself is obviously elongated, and off centre from the central star.

    Vela Globular NGC 3201: Interesting to compare with NGC2808 in Carina. A spread out glob, not strongly concentrated like NGC2808. At 16000ly, it is half the distance of NCG2808, and only slightly dimmer in total brightness, but the disperse nature of this glob spreads out the light making it harder to see. There are far fewer stars in this glob, but this makes individual stars easier to see. A moderate size scope will resolve this cluster into individual stars.

    NGC2899 Planetary Nebula: Another tiny nebula to hunt down. Dimmer than 2867 nearby in Carina.

    Double star HIP 51561: An easy, fairly wide, even double, 5.6/6-14". No trouble with 60mm at 50x.

    Double star Dunlop 70, HIP 41639: Moderately easy close double 5.2/6.8-4.5"

    Double star h4188 HIP 45189: John Herschel (h). Near Suhail. Close pair 6/6.8-2.9".

    Triple star h4104 HIP 41616: Nice triple. Near Regor. mag 5.5 star with mag 7.2 very close on one side, and mag 9.2 further out on the other side. 5.5/7.2-3" + 5.5/9.2-19"

    Double star x Velorum, HIP 52154: Wide easy pair. 4.2/6.0-60"

    Triple star J Velorum, HIP 50676: Moderately easy double, plus dimmer third star widely spaced at right angle. 4.5/7.1-7" + 4.5/9.1-36"

    CHART 2: Puppis, Canis Major, Columba

    Puppis

    Puppis is a long constellation sweeping along the narrow stretch between Vela and Canis Major, from the bright star Canopus, then wrapping around Canis major, all the way to Monoceros towards Orion. This is also a nice area for binoculars. Many of these objects will pop out, demanding extra attention.

    C-Puppis Cluster NGC2451: A scattered cluster of bright stars around the bright orange star C-Puppis. A nice contrast to the nearby NGC 2477.

    B-Puppis Cluster, NGC2477, Caldwell 71: A dense, rich, cluster of hundreds of stars near the star b-Puppis. It looks is a bit similar to the globular NGC 3201 in Vela, or the open cluster M46, also in Puppis. It resolves nicely in moderate telescopes. It has fairly high total brightness (mag 5.8), however it does not contain individual bright stars and is not strongly concentrated, making it appear fainter.

    M93: A fairly small and compact open cluster. Obvious as a fuzzy spot in binoculars. Resolves nicely in moderate scopes.

    Binocular Double Xi Puppis: Wide double, almost naked eye, easy in binos. 3.3/5.3-290", bright star near M93

    Double star k-Puppis: The Perfect double star! Two even yellow "headlights" nicely spaced for any telescope to split them apart. Always a pleasure to see.

    Emission Nebula NGC2467: This is a small emission nebula, moderately bright with a dark sky and an 8" scope.

    M47: Large scattering of bright stars with a few nearby bright stars. Signpost to help find M46

    M46: Even and fairly dense cluster of dimmer stars. No strong concentration. Easy to find once you find M47. Resolves fairly easily in moderate scopes. Includes a small planetary nebula in the same line of sight. The pair of M46 and M47 can be compared to the pair of b and c Puppis.

    M46 Planetary, NGC 2438: Tiny planetary nebula in the same line of sight as M46. Nebula filter helps to dim the stars so the nebula is more visible.

    L2 Puppis variable star: This one has been playing up recently. It is a semi regular Mira like star, with a period of 140days, and a historical variation of about 2-3 magnitudes, from magnitude 3 to 6. It has been getting steadily dimmer since 1995, and has recently varied between about magnitude 6 and 8.5. Over the last year the variation has reduced. The star is now being intensely studied to try to determine what is going on. Amateur observations of this star is a core part of the research. The next peek is due around June/July. Will it brighten back up to magnitude 6? What that space! Go to https://www.aavso.org/lcg/and enter "L2 PUP" for the last 1000 days.

    Canis Major

    The big dog, Canis Major, is to the west this time of year. Sirius, the brightest star in the sky, is at the lower end of the constellation. Sirius is getting low in the sky by 10pm, and will get lower as over the next month. Here I have focused on the objects higher up in the constellation.

    M41: This will get low early, so take a look at this one first. M41 is a large scattered open cluster, starting to resolve in binoculars, and clearly visible at low power in a telescope. On a dark night this can be seen naked eye with averted vision.

    Caroline's Cluster, NGC 2360: Named after it's discoverer, Caroline Herschel, sister of William Herschel. It contains many stars of similar brightness in a fairly compact cluster, set in a rich part of the milky way. This is an old cluster, about 2.2 billion years, so the bright blue and red stars that dominate newer clusters have burnt out long ago.

    Tau Canis Major Cluster, NGC 2362: The bright star Tau Canis Major is at the centre of this cluster. It is so bright that the other stars are not obvious in binoculars, or with a bright background sky. But with darker skies, and medium power this is a stunning cluster. The fainter stars are scattered all around the bright star, in a vaguely triangular shape.

    Double star 145 Canis Major: This is a superb double star. These orange and blue stars make a great contrast. The are widely spaced, and easy to find. Looks for the 3 stars in a rough line at the top right end of the constellation. Tau CMa is the top star, and the third star is 145 CMa. Tau CMa is separated from the other two at the Sirius end.

    Columba

    The two bright stars of this constellation are clearly visible near Canis Major. From these, a "three legged" asterism can be traced out under moderately dark skies. With good imagination this represents a Dove. There's not a lot to see here, but I've included it mostly to give a reason to hunt down this less well known constellation.

    Triple star h3857, HIP 30444. Wide and easy pair of unrelated stars HIP30444 and HIP30455, 5.7/6.9-64". The brighter star is also a double, with a faint companion 13 arc seconds away on the opposite side, 5.7/9.5-13"

    Columba Glob, NGC 1851: The brightest globular cluster in Columba. Strongly concentrated with many stars. Similar in size and concentration to NGC2801 in Carina, but dimmer. Visible in binoculars, but a 6" scope is required to resolve it.

    Galaxy Pair NGC1808 & NGC1792. Only 2/3 of a degree apart, visible in the same low power field. Both magnitude 10, but fairly concentrated spiral galaxies. Visible with 8" scope under a dark sky.