AstroBites-3: Conjunction

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I was up early this morning in order to view and image the rare visual conjunction of Jupiter and Venus.  Unfortunately I cannot see the eastern horizon from here but from the top of Redhill Common adjacent to Fairvale Observatory there is an excellent view and just before 6.30 a.m. I climbed to experience the spectacle.

Following a cold, clear night the early morning weather was excellent and I was able to obtain a number of images as well as a good view using binoculars.  It was a short but worthwhile event, as shortly after 6.50 a.m., with growing brightness from the impending sunrise due at 7.14 a.m., the view of the conjunction was soon lost.  The next Jupiter–Venus conjunction will be on 30th April 2022, so time to recover!

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Arctic Antics

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The globe pictured above on the island of Vikingen marks the location of the Arctic Circle off the western Norwegian coast.  However, surprisingly the position of the Arctic Circle is not fixed – as of 28 February 2017 it was 66°33′46.6″ north of the Equator but changes depending on the Earth’s axial tilt, which itself varies within 2° over a 40,000-year period due to differing tidal forces that occur as the Moon’s  orbit changes around Earth.  The region north of the Arctic Circle is famous for the midnight sun in the summer and its corresponding 24-hour darkness during the winter months, with major implications for life itself, as well as contrasting scenery and photographic conditions unique to this hostile region.

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During the last two weeks of February, when the return of limited daylight has just begun to mark the end of winter, I travelled by ship along the entire western and northern coast of Norway close to the Russian border, spending much of the time within the Arctic Circle.  The area is famous for its beautiful scenery, in particular the fjords which typify the coastline and for time immemorial have posed a significant challenge to all seafarers passing this way.

Our ship, the Richard With, was named after the Norwegian captain who in 1893 pioneered this difficult sea passage which we took from Bergen to Kirkenes and back.  Today a fleet of 12 ships are operated by the original Norwegian company Hurtigruten on a daily basis providing ferry transport for goods, vehicles and personnel, as well as a base for tourists seeking a view of the Northern Lights – in all the ship stops at over 30 ports in each direction.

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Apart from the scenery, during the winter months the area north of the Arctic Circle is probably best known for the occurrence of the Aurora Borealis or Northern Lights (Norwegian – Nord Lys).  A view of this feature is treasured by all who see them but for astrophotographers it will be one of their ‘must do’ images to acquire.  The Aurora is caused by a solar wind originating from the Sun that consists of charged particles, which when drawn downwards at the Earth’s poles by the planet’s magnetosphere ‘excites’ atmospheric atoms which produce different coloured lights depending on the type of gas which is excited by the charged particles; a similar feature occurs around the South Pole called the Aurora Australis and is also now known to occur on Saturn and Jupiter.  The lights are mostly green in colour (ʎ 557.7 nm), sometimes red (ʎ 630 nm) or blue (428 ʎ nm) and less commonly pink, ultraviolet or yellow, depending on the altitude and type of excited gas – which is mostly either oxygen or nitrogen.  The resulting aurora takes the form of rapidly moving clouds or often curtains of light that dart across the night sky, constantly changing shape under the influence of the Earth’s magnetic field and does not disappoint when seen.

The Northern Lights are best imaged with a standard DSLR camera on a sturdy tripod, using a wide angle lens at full aperture, set at between ISO 800 to 1,600 and exposures of about 8 secs to 25 secs, depending on the brightness and quality of the light and the speed of movement of the aurora; focus and all other control needs to be operated manually for best results.  On land a tracking mount, such as a Vixen Polarie, could be used to improve sharpness but on a moving ship set-up and technique is a more difficult.

In this case exposure needs to be carefully balanced in order to account for the ships movement – forwards + up-and-down on the water – and the quality of the aurora light.  As exposures will always need to be greater than a few seconds, star trails are unavoidable and have to be dealt with in post processing as best as possible. I found imaging directly forwards or to the rear of the ship helped minimise this effect but still trails were still inevitable. Experimenting with various settings I found about 12 to 15 seconds exposure and ISO 1,600 generally worked quite well but varied depending on the sea conditions and nature of the aurora at any time.

At such high latitudes it is still very cold in February and warm head-to-feet-to-hands clothing is absolutely essential.  On this occasion, together with wind chill the temperature at the ships bow ranged from between -20oC to -30oC (that’s a minus sign!), making camera control very difficult and uncomfortable!  I tried using an intervalometer for remote shooting but as settings have to be changed frequently by hand it was not very practical; I’m sure on land it would prove much more helpful.  Furthermore, much of the time I had to hold the tripod down with some force as the wind was very severe.

Notwithstanding, I’m very pleased with the results shown below and would love to return again one day, perhaps in the summer – it is a truly different and very special part of the world – hat’s off to Richard With and all those who still sail these waters.

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Spring Skies

It’s three weeks since the Spring Equinox and two weeks since moving to British Summer Time (BST or daylight saving, GMT+1 hour), the result is that the night sky starts much later in the evening and is rapidly decreasing in length; it is just about six weeks before Astronomical Darkness completely ceases and will not come back until the end of July.  In addition, through a combination of European pollution and fine sand from the Sahara drifting over South East England this week, otherwise clear skies were badly obscured by the resulting haze.  As a result, since shortly before the full Moon on April 4th astronomy has not been possible – until last night.

The march of time and annual movements of the Solar System inevitably lead to a significant loss of quantity and quality of darkness at this time of the year.

The march of time and annual movements of the Solar System inevitably lead to a significant loss of quantity and quality of darkness at this time of the year.

Taken this morning, the contrails over Fairvale Observatory make a striking picture but, together with other pollution are having a significant impact on seeing conditions here at the moment.

Taken this morning, the contrails over Fairvale Observatory make a striking picture but together with other pollution are having a significant impact on seeing conditions here at the moment.

In the early evening twilight sky for a brief period between sunset and astronomical darkness, at the moment Venus is low on the western horizon.  Last night its apparent position was also close to the Pleiades star cluster, making an attractive widefield photograph.  Furthermore, shortly before Venus moved below the horizon and the sky had nearly reached Civil Darkness, the constellation Taurus also became visible to the south west with the bull’s ‘eye’ star Alderbaran and the v-shaped Hyades star cluster clearly evident.

Venus at sunset last night.

Venus at sunset last night: the Pleiades can only just be seen at 2-o’clock to Venus with Taurus on the far left.

Twenty minutes after sunset shortly before reaching Civil Darkness, the Pleiades and Taurus constellation are now quite clear.

Twenty minutes after sunset shortly before reaching Civil Darkness, the Pleiades and Taurus constellation are now quite clear.

Such a picture is a reminder that it is important to consider photography other than telescopic based planetary and deep sky imaging, especially as viewing and imaging conditions become more limited over the forthcoming Summer period.

Two’s Company

During the late 20th Century planetary relationships took on a new meaning as a metaphor for the difference between men and women, following the publication of John Gray’s book Men Are From Mars, Women Are From Venus.  Making a beautiful view at the moment, Venus is currently flirting with Mars in the early evening sky, for a very brief period low on the western horizon just after sunset. Its appulse with Mars can be easily seen with the naked eye but the view from Fairvale Observatory lasts only about 20 minutes and therefore requires good seeing conditions and quick action to get a picture.

At the weekend the view was even better, with the crescent of the New Moon adjacent to the field of view of Venus and Mars at the same time but my camera was not ready. Ideally I would like to image its apparition with a telescope but having to act quickly, last night I managed to get a quick photograph of the two planets using a DSLR camera and a 600 mm telephoto lens; the International Space Station flew by shortly afterwards but unfortunately too late get a photograph combining all three, timing is everything.

Later in the month the apparition of Venus will also include Uranus, making an even better show but will definitely not be a case of two’s company, three’s a crowd!

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Shining brilliant white, magnitude -3.9 Venus – top left & the smaller, faint magnitude +1.3, red planet of Mars – bottom right

STOP PRESS!

Another good evening sky this evening and tonight I manged to set-up the telescope to take this beautiful picture of Venus and Mars:

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