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Stargazers' Almanac 2018

Stargazers' Almanac 2018

A monthly guide to the stars and planets

Inside the Stargazers' Almanac:

  • Monthly North and South facing A3 star charts for latitude 52 degrees North with planet positions and phases of the Moon
  • Overhead sky star map
  • Constellation and zodiac positions

Also Featuring:

  • Our place in the Milky Way Galaxy
  • The UK's darkest places
Price:   £14.00

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BAA Gallery Picture of the Week
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A Different Perspective on C/2016 R2

Image
About this observation
Observer
Ian Sharp
Time of observation
15/01/2018 - 20:54
Object
Comet C/2016 R2 (Panstarrs)
Observing location
Near Tarife, Spain
Equipment
Camera: Canon 6D (Astro-modified) at ISO 1600
Lens: Canon 50mm f/1.4 at f/3.2
Mount: AstroTrac on photo tripod
Exposure
30 x 60 secs
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With this image Ian has brought home to us how deep and perceptive are the other images of this comet, taken by larger instruments.  This image gives a fascinating insight into the scale of the comet against the background of the stars in the Taurus region.

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
BAA Gallery Picture of the Week
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Comet C/2016R2 (Panstarrs)

Image
About this observation
Observer
Damian Peach and Jose J Chambo
Time of observation
07/01/2018 - 23:00
Object
Comet C/2016 R2
Equipment
16"ASA and 20"CDK
Exposure
LRGB - 36mins L and 5mins RGB
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I make no apology for running yet another Damian Peach image as PotW.  This stunning image was a joint effort between Damian, who captured the Luminance, and Jose Chambo who supplied the TGB data.

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
BAA Articles

Mira a ‘Wonderful’ Maximum

On the morning of August 3rd, 1596, German astronomer David Fabricius used an unmarked third magnitude star in Cetus as a reference point for marking the position of the planet Jupiter. When he returned to that star three weeks later he noted that it had brightened by a whole magnitude, but by October the star had faded below naked eye visibility and the event was interpreted as a Nova. Fabricius recorded it again in 1609, by which time other astronomers had begun to make observations themselves. In 1638, the Frisian astronomer Johannes Holwarda determined a period of 11 months for the stars reappearances in the night sky, and is generally regarded as the discoverer of the stars variability. The Polish astronomer Johannes Hevelius named it Mira – the wonderful – in his publication Historiola Mirae Stellae in 1662, simply because no other star behaved in such a manner. We now know it as omicron Ceti, the first variable star to be (officially) discovered, and would later lend its name to a whole classification of variable stars – the Mira type pulsating stars!

Mira is a red giant AGB pulsating star of spectral type M7, some 650 million km in diameter yet only slightly more massive than our sun at 1.2 solar mass. It’s magnitude range is 2.0-10.1V and its period is 331.96 days. Mira is also a double star, with it’s white dwarf companion itself a variable star known as VZ Ceti. The orbital period is a very lengthy 500 years! Some sources indicate that the companion may be a main sequence star of 0.5 solar mass, yet recent studies seem to indicate that the companion is in fact a white dwarf which is accreting material from Mira’s stellar wind. The two stars are separated by ~100 AU, and the whole system is ~350-400 light years from Earth. Binary systems such as this are also regarded as a symbiotic star system, and Mira and VZ Ceti are in fact the closest of this type of variable star to our Sun. In 2007 the UV satellite Galex discovered that Mira was speeding through space at 130km/ps (proper motion of 10 milliarc-seconds per year), and leaving in it’s wake a tail of shed material 13 light years long, revealing a history of Mira’s mass loss over a period of some 30,000 years. The truly remarkable image can be seen here.

Wide field chart of Mira's location

The winter of 2018 is the perfect time to observe this amazing star for yourself – without the need for any optical aid - and as I write these words (January 8th), Mira is approaching maximum magnitude and is an easy naked eye star in the evening sky as darkness falls (on January 7th it was seen at mag. 3.7 with the naked eye from Birmingham). This maximum follows one of the faintest minimum on record, when Mira reached a mean magnitude of 10.26 at the end of September and the beginning of October 2017. The last time Mira was seen as faint as this was in 1930!

Mira will be at maximum for around a week before any fade is noted, and will remain bright enough to be visible with the naked eye (in a dark sky) or small binoculars until the field sets in the early evening during the first half of March. As the period is 331 days, three observations per month will be sufficing to monitor the maximum and decline. The star doesn’t vary fast enough to warrant more frequent monitoring, and over observing in slow varying stars can introduce bias. Mira is very easy to identify with the naked eye at the moment, lying some 6 degrees SW of delta Cet and 7 degrees SE of alpha Psc. Its position is

02h 19m 20.8s -02d 58’37” (2000.0)

The BAAVSS have produced three charts to enable observers to monitor the whole phase from maximum to minimum – a 60-degree chart for maximum, and 18-degree and 5-degree charts as the star fades. These are available for download from the Variable Star Section's website, following the Charts, Cet and then Omi Cet links.

The BAAVSS has over 17,000 observations of Mira dating back to 1885, so why not add to them by reporting your observations to the section? Don’t worry if you haven’t made a variable star estimate before, as there is always plenty of advice available from the Section Officers. And whilst you are looking at this remarkable star with your naked eye, just try to imagine this enormous pulsating red giant decreasing in size as it approaches maximum, then expanding as it fades, its mass loss to its companion star, and the amazing 13-light year long tail left behind as Mira whizzes through space. Has any star in our night sky ever been so appropriately named?

Mira.  1,130 visual observations from Jan 01 2007 to Jan 07 2018.  BAAVSS database.

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BAA Gallery Picture of the Week
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Eta Carinae and the Homunculus Nebula

Image
About this observation
Observer
Damian Peach
Time of observation
26/12/2017 - 23:00
Object
Eta Carinae
Observing location
Chile
Equipment
1 meter telescope
Planetary camera
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This image is of the tiny Homunculus nebula surrounding the highly luminous star Eta Carinae.  The nebula spans only 18" in size and Damian used the planetary camera on the 1m telescope in Chile.
Damian comments that quite a detailed result was possible, clearly showing darker dusty patches and brighter blobs within the nebula. The double lobed appearance is striking.
Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
BAA Gallery Deep Sky Nebulae
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IC 443 - The "Jellyfish" Nebula

Image
About this observation
Observer
Kevin Gurney
Time of observation
15/12/2017 - 23:00
Object
IC 443
Observing location
Sheffield, UK
Equipment
Altair Astro 10" Ritchey-Chretien truss tube
ATIK 460EX Mono Camera
Exposure
Baader Planetarium B 1" 1/4: 8x120" -15C bin 1x1 Baader Planetarium G 1" 1/4: 8x120" -15C bin 1x1 Baader Planetarium Ha 1.25" 7nm: 13x420" -15C bin 1x1 Baader Planetarium OIII 1.25" 8.5nm: 4x420" -15C bin 1x1
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Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.
BAA Articles

A January Mars Jupiter conjunction in the morning sky

After conjunction with the Sun last October, planetary observers will be relieved to know that Jupiter is now back in the morning sky (like many people, I always feel there is something missing when Jupiter is not around). In early January it rises around 03:30UT and by the start of astronomical sunrise at 06:00 is 17 degrees above the south-eastern horizon. Not to be outdone Mars is also on display, albeit at mag 1.5, so significantly fainter than brilliant mag -1.8 Jupiter.

 On January 3 the two planets will be just under 2 degrees apart and if we are lucky enough to have a week of clear skies (or at least a few clear mornings) it will be fascinating to watch Jupiter catch and then overtake Mars as it makes its way towards opposition on May 9 (Mars reaches opposition on July 27). In this game of planetary overtaking Jupiter is 1 degree from Mars on January 5 with the two planets closest on January 7 (a Sunday morning) when only around 15 arcminutes separates them, with Mars lying just south of Jupiter. By the end of the month the separation will have increased to 12 degrees and Saturn (magnitude 0.6) will also have joined them in the morning sky, rising around 05:40UT.

 At closest approach on January 7, Jupiter will display a disk diameter of 33 arcsec while tiny Mars only manages just under 5 arcsec. If the weather obliges this close approach could make a stunning observing or imaging opportunity. On this day of closest approach at 06:00UT (see sky chart below), telescopes will show the Galilean moons Ganymede and Calisto lying 4 arcmin to the west of Jupiter and Io and Europa around 1 arcmin to the east. The Moon on this date will be 5 days past full and lying in the south-west. Moving further ahead, on February 7 the last quarter Moon joins in the morning display with Saturn, Mars, Jupiter and the Moon strung out along the ecliptic and even tiny Pluto, perhaps trying to pretend it is still a planet, only just below the eastern horizon!

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BAA Observing calendar

Second Full Moon in January - Blue Moon

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