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By Sam
Hello, The link below is a round up of the southern sky in January from the point of view of Wellington in New Zealand. We’ve tried to capture a bit of a cultural flavour too with some of the night sky descriptions that are relevant to Māori. So if anyone is heading down to the Southern Hemisphere in January then be sure to have a look at some of the objects - if you’re already in the Southern Hemisphere, you might find it useful too. Here it is :The January 2018 Night Sky.
Sam
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By A budding astronomer
Eridanus, a dim constellation that is always overshadowed by it's brighter neighbors. These include Orion, Taurus, Monocerous and Canis Major. But these objects have many features of interest. Orion has the beautiful awe-inspiring Orion nebula, Taurus with incredible naked eye open clusters such as the Hyades and the Pleiades ( Subaru cluster ), Monocerous and its wealth of Nebulae and last but not least Canis Major with incredible Messier objects and it's beautiful gem that happens to be situated in the Great Dog's jaw, Sirius A and B.
But what about the faint, long constellation of Eridanus the river? Does it have anything to show our eyes and optical equipment? Indeed it does and some objects in it are very underrated indeed. Lets take a look at these objects in this very mysterious constellation.
BINARY STARS: We start our list with 63 Eridani, a magnitude 3.9 star situated in the gap between Lepus and Eridanus. It and its companion have a separation of 1.1 arc seconds, It will be a challenge for small telescopes. It is situated in a place where there are no bright stars around it.
32 Eridani: A beautiful binary star I stumbled across last night through my telescope! This lovely double has a topaz yellow primary and a sapphire colored secondary with superb contrast. They are 7 arc seconds apart and are at a distance of 300 light years away and are of +4.8 and +5.6 magnitude. Kind of like Beta Cygni for larger telescopes!
55 Eridani: Also known as Struve 590 is a dim yet pretty pair of stars, The primary star at +6.7 magnitude is a deep yellow color and the secondary is a deep blue shining at magnitude +6.8. They are separated by 9 arc seconds.
Keid/Omicron2 Eridani: A triple star system 1 degree away from Beid or Omicron1 Eridani. The primary star is of magnitude +4.4 and the B star is of +9.5 magnitude 104 arc seconds away. while the C star is magnitude +11.2 and 9 arc seconds from the B star.
Acamar: Acamar is a pair of stars seperated by 8 arc seconds.
DEEP SKY OBJECTS: Sadly there is only one deep sky object of interest and that is the Witch Head Nebula. Located in between Rigel and Cursa ( Beta Eridani ) it appears as 160 x 60 arc minutes in size. It gets it's blue color from Rigel.
VARIABLE STARS: The only variable star I know that changes quite a bit in magnitude is Lambda Eridani which changes from magnitude +4.2 to +4.4 over a period of 0.7 days.
INTERESTING STARS: Epsilon Eridani: At a mere 10.5 light years away, this is the tenth closest star to Earth. This lovely yellow star shines at +3.7 magnitude and appears to be a part of a small triangle along with a +6.3 magnitude star and a + 7.3 magnitude star. the 7th magnitude star is actually a nice binary with the secondary star shining at magnitude +8.6 separated by 130 arc seconds.
Zibal/ Zeta Eridani: This star may not have any interesting features or facts, but last night when I was observing it with my telescope when suddenly a HUGE fireball crossed it and scared the living daylights out of me! So keep a close eye on Zibal!
Hopefully you can observe these objects and find alot of interest in Eridanus. If I missed anything please leave a reply since I live in the Northern hemisphere I might have missed some of the more southern objects.
Thanks for reading
A budding astronomer.
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By Putaendo Patrick
The entire sky is now divided into 88 Constellations defined by the IAU in 1922. But their history goes way back to prehistory. The Ancient Greeks combined the legends of Chaldea, Babylon and Egypt with their own and began to formalise a complete iconography of the sky as viewed from the Mediterranean. The stars were associated with mythological characters in a series of popular stories generally related to sex and/or violence. Perhaps the idea was to create a mental map of the sky, or in an age of primarily oral tradition, perhaps to use the stars as an aid in remembering the stories.
One of the first Greek astronomers to compile a catalogue of the visible stars was Eudoxus of Cnidus. Unfortunately his original work has not been preserved, but Aratus (apparently born in Solis in modern Turkey ca. 315 BC/310 BC – 240 BC) used this list to write a didactic poem, the Phaenomena, telling the stories. There's an on-line English translation at:
http://www.theoi.com/Text/AratusPhaenomena.html
By all accounts the poem was tremendously popular. A century later, Hipparchus (whose own star catalogue was used by Ptolomy) criticised its accuracy, but praised it as a literary work. It was translated into Latin by several distinguished Roman authors, including Cicero, and survived as one of the few astronomical texts in Western Europe during the Dark Ages. Early on, the poem was illustrated – and, although the original Greek and Roman examples have been lost, there are apparently more or less faithful later copies dating from the early 9th Century AD which are associated with the church and court of Charlemagne and his son, Louis the Pious.
Three of the best these manuscripts survive respectively at the University Library in Leiden, the British Library in London and the National Library in Madrid.
Hercules from the Leiden Aratus
The Madrid Aratus showing Eridanus, Pisces and Ara
Centaurus from the London Aratus
Although all are based on Aratus, the three are in fact very different, presumably copied from three distinct Late Roman sources. The Leiden Aratus is essentially a picture book in a small format, probably commissioned by a wealthy and important patron for personal enjoyment. The Madrid manuscript on the other hand is a collection of different works intended to aid “computus” or the astronomical calculation of the calendar and was probably produced as a result of a conference of clerics on the theme in Aachen in 809. The London manuscript ingeniously incorporates the pictures of the Constellations into calligrams, images made from words.
The Leiden Aratus was exhibited at the Getty Museum in Malibu. The catalogue with photos of most of the Constellations is available at:
http://www.getty.edu/publications/virtuallibrary/0892361425.html
The London Aratus is available as very detailed zoom-able scans at:
http://www.bl.uk/manuscripts/FullDisplay.aspx?ref=Harley_MS_647
Black and white photos of the Madrid Aratus are available at the Warburg Institute Iconagraphic Database:
http://warburg.sas.ac.uk/vpc/VPC_search/subcats.php?cat_1=9&cat_2=71&cat_3=32&cat_4=39&cat_5=975&cat_6=453&cat_7=245
The complete manuscript is digitally scanned at:
http://bdh-rd.bne.es/viewer.vm?id=0000122617&page=1
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By neil groves
I did this image of Cassiopeia as I wanted some files to play with to get used to DSS, i'm both pleased with the result and disappointed, pleased because I snagged an aweful lot of stars and they are round pin points instead of blobs lol
disappointed because I know that the milky way runs across this patch of sky and I have seen beautiful images full of colour, I failed to get any of the milkyway to show up even after stretching, and any colours I managed to capture in the stars are very subdued, this is only my second attempt with DSS though and i'm sure there is a learning curve to navigate.
I'm sure the short exposure has a lot to do with my results though and much time will be spent experimenting ;-)
Camera - Canon 5D
Lens - Canon 70-200L @ 100mm f5.0
Exposure -
Lights 20 X 5 secs
Darks 10 X 5 secs
Static tripod.
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