The main henge posts are now in place. Markers and smaller posts for the Celtic cross quarter days still to be added.
More progress on the wood henge and Celtic calendar up at Abriachan Forest, with the main posts for the meridian, equinoxes and solstice rise and set positions now in place.
Not quite finished yet. Abriachan plan to sow seeds for next few weeks and let the ground within the perimeter settle.
Descriptive marks for the main posts and small posts for the Celtic Cross Quarter days Imbolc, Lammas, Samhain and Beltane will be added later.
In addition to tracking the Sun and measuring the solar year, we can use the henge during the stargazing programme to record the rising of new seasonal constellations in the East and rough measurements of the transit altitudes (due south) and azimuth positions of the stars.
We also had a great kick off to the Star Stories program last night with ancient astronomy learning, storytelling and activities for the young ones.
The next event will be Nov 23rd with guest astronomer and author Steve Owens (aka Dark Sky Man). Booking links will go up shortly.
I’ll be touring the outer Hebrides delivering outdoor stargazing as part of the Hebridean Dark Sky Festival 2020. The festival is a fantastic reason to visit the isles during the winter months and appreciate their world class dark skies. Organisers An Lanntair have put a fantastic programme together spanning music, art, theatre and stargazing.
Details of my own route and outreach locations for stargazing will be published soon so stay tuned. For full festival details and some early booking links please visit the festival website.
One of the most stunning images ever take of Saturn by the Cassini space probe – the planet backlit by the distant Sun, with the normally faint E ring glowing in a blue halo of light.
At the kick off for the new Merkinch Nature Reserve astronomy programme tonight, I got to talk about one of my favourite planets of all time – Saturn and its mind blowing ring system.
The dynamics of the rings are so subtle and complex. Some of the gaps in the rings are made by moonlets clearing paths, whilst other moons are actually replenishing the rings.
The small moon Enceladus is a fascinating example. It’s spewing out frozen ice from its south pole due to tidal heating, effectively generating Saturn’s faint E ring (the faint blue outer ring pictured above).
Enceladus, a small icy Moon with a salty internal ocean. Tidal stresses imparted by Saturn produce great jets of water from the southern pole of Enceladus, which instantly freeze, adding icy material to Saturn’s E ring.
You could sit on a moonlet of Saturn and watch the rings forming little wavelets in real time around you. Some of the larger rings actually wash back and forth like waves on a giant ocean.
Many of the smaller moonlets orbiting Saturn have a polished or smooth aspect to them. This is due to fine particulates from the rings being drawn towards them due to gravity, effectively power coating the surface and covering over any craters or blemishes. This accretion of material onto the moons has been imaged by Cassini.
We had great turnout for the kickoff. The next event is a Moon special on Nov 7th. Look out for eventbrite links here on on my Facebook page.
The tiny moon Pan, clearing a path through Saturn’s rings. Its gravity is strong enough to produce beautiful ripples within the rings. As it orbits, Pan receives a fine power coating of frozen dust from the rings lending the moonlet a smooth, polished appearance.
The northern lights looking over the Beauly firth towards the Black Isle, Inverness-shire
After reports of a KP6 geomagnetic storm predicted to strike Scotland over the weekend, and clear skies on Sunday evening, I headed out after sunset to try and catch the northern lights. This was a very early aurora excursion as nights have only just got dark enough for decent views of the night sky, let alone tracking down the faint and elusive northern lights.
My initial outing took my into the hills above Bunchrew where I bagged some lovely views of the summer Milky Way overhead. Turning my attention north I noticed a faint arc of light on the horizon, and sure enough some test shots picked up a vibrant band of purple and green auroral light. However little structure was evident until I moved to lower elevations, reaching the Bunchrew shoreline just after 10.30pm.
The Milky Way near Cygnus, framed between trees above Bunchrew.
From this new vantage, in the dark looking over the Beauly Firth, the northern lights stood out much more clearly as distant columns of white light, slowly morphing and scintillating above the horizon. Some of the images (attached) show nice structure and the suggestion of wave like movement.
As our nights get darker many more opportunities to view the aurora will present themselves. The best strategy is to simply get out there as often as you can when it’s clear, and try and escape the boundaries of light polluted towns and cities. Aurora forecasts should only be used as a guide as they’re seldom reliable. Remember to look north and where possible find some nice low horizons in this direction.
Good luck and clear skies.
The aurora is caused by the solar wind slamming into the earth’s atmosphere near the poles, ionising chemical elements which produce light at very specific quantised frequencies.
The summer aspect of the Milky Way, the great river of starlight marking our home galaxy. A giant stellar disk containing 100s of billions of stars. Photograph by Christopher Cogan, taken near Muie in east Sutherland, Scottish Highlands
Late summer is prime time for observing the Milky Way, and esp. catching the bright core visible near the southern horizon after dark. This bright area marks the central nucleus of our galaxy, some 30,000 light years away..
The Milky Way currently runs between Saturn and Jupiter, both low on the southern horizon, and intersects the three bright stars of the Summer Triangle asterism (Vega, Deneb and Altair). From south It runs overhead and terminates close to the constellation Perseus in the north East.
For the best views you’ll want to get away from urban light pollution, ideally somewhere fairly rural. Let your eyes dark adapt for at least 15 minutes to give yourself the best possible views.
I had a fun afternoon surveying the markers in preparation for the final Wood Henge up at Abriachan Forest.
The final construction will mark the meridian from north to south, the equinoxes, mid summer and mid winter rising and setting positions of the Sun. Between the main solstice posts we’ll eventually place markers for the ancient cross quarter days, or Celtic Wheel of Time.
A simple henge like this can track the solar year, lunar rising positions and the changing constellations in the night sky.