The Cat’s Eye Halo

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Image Credit: R. Corradi, Nordic Optical Telescope

I recently stumbled across this stunning image of the famous Cat’s Eye nebula. It’s a false colour enhancement showing the extended ejecta from the dying star, imaged by the Nordic Optical Telescope on the Canary islands..

The cat’s eye is dubbed a ‘planetary nebula’. An erroneous label as this has nothing to do with planets whatsoever. Rather these nebulae are the beautiful symmetries left behind when stars of similar mass to our Sun enter their final gasps of life. Before collapsing down to a white dwarf (a compact star held in place by electron pressure), the star sheds its atmosphere is great puffs, producing these ghostly but beautiful clouds of ionised gas.

I made a video about Planetary nebulae you can watch here:
https://modulouniverse.com/2019/03/03/planetary-nebulae-video/

The outer gaseous tendrils seen in this image extend almost 3 light years across and probably represent earlier and more transient episodes of stellar influenza, before the star began its collapse in earnest.

Image Credit: R. Corradi, Nordic Optical Telescope

An Alien Solar System

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A direct image of an alien solar system orbiting a Sun like star, over 300 light years away!

I remember growing up in the 1980s hearing about the ‘high probability’ that other stars had orbiting planets, but there was very little evidence then, only some tantalising hints from the gravitational wobbles observed from specific stars.

Since then thousands of new exoplanets have been confirmed using the transit and radial velocity detection methods. I wrote a blog article about this a while back.

These methods are indirect ways of determining the existence of planets, and it’s very rare to actually be able to ‘see’ the planets themselves.

This image is therefore pretty incredible and for me suddenly normalises the idea that these star systems are real places we could, theoretically at least, visit in the distant future.

The image was captured by the European Southern Observatories Very Large Telescope and shows a young Sun like star (only 17 million years old) with two clearly defined giant planets in orbit. (The dots of light closer to the star are background stars and therefore not part of this particular planetary system)

These planets orbit the star at 160 and 320AU (1 AU is the Earth to Sun distance) so they’re much further away from the star than any planet in our solar system.

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‘Gamification’ – Stellar Evolver

An example of gamification in one of my recent projects called Stellar Evolver (with audio voiceover). This is a fully VR ready experience and will enable players to interact with and watch the evolution of star systems using the visceral mechanics and feedback of a 3D based shooter.

Stellar systems can evolve from simple proto-planets up to red dwarfs and larger giant stars, eventually culminating in the formation of neutron stars and black holes.

Clearly the overall dynamics, scale and time is being exaggerated here for playability. I hope to demonstrate a working multiplayer prototype at the 2021 Hebridean Dark Sky Festival.

Developed by Mackintosh Modelling & Data Simulations
modulouniverse.com

Sirius the Glitter-ball

 

A video of Sirius (the brightest star in the night sky) twinkling on the horizon, captured by Steve Brown @sjb_astro. Many people think they’re seeing a low altitude aircraft or UFO when they witness this.

This phenomenon occurs (to a lesser extent) with any bright star low on the horizon due to the vast amount of atmosphere you’re seeing it through. As stars gain elevation, and less atmosphere is between us and them, they shine more steadily, and views are hugely improved.

The difference in the amount of atmosphere you look through with elevation is very striking (as demonstrated in the sketch below).  Particularly for faint deep sky objects like galaxies, high elevations makes a dramatic difference to the quality of visual or photographic images you’ll collect.

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How much atmosphere you look through with observing angle.  At the zenith (overhead) you look through over 2/3 less atmosphere than at the horizon.

Betelgeuse visibly dimmer

I can’t get over how much dimmer Betelgeuse in Orion appears at the moment. To my eye Aldebaran (a red giant) in Taurus now appears obviously brighter.

This was an image taken last winter.

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Orion image from winter 2019

Many click bait astronomy articles have surfaced claiming the star might be dimming due to its impending collapse and rebound as a supernova, but Betelgeuse is a known variable star and similar changes in its brightness have been noted in the past, although recent changes appear to deviate from established patterns.

Unusual gravitational waves have also been detected in the vicinity of the red supergiant, adding to the sense of mystery.  It’s important to note that these waves are merely in the vicinity, so could easily be generated by countless other sources behind Betelgeuse.

Still, it’s fun to speculate about the possibility of witnessing a relatively close supernova event in our lifetime.  The last two major naked eye supernovas were recorded in 1572 and and 1054, in Taurus (the Crab nebula) and Cassiopeia (Tycho Brahe supernova).  Both generated enough luminosity to be visible in daylight for several weeks, and shone as new ‘guest stars’ for around a year or so before fading.

Some work published by Dolan in 2016 estimated the impact of a Betelgeuse supernova on Earth and found it to be negligible.  At 500 light years distance the residual energy of the vastly expanded shockwave would be exponentially diminished as it passed Earth.  However the brightness predicted would be magnitude -12.4,  making such an event more luminous than a full Moon!

For the mathematically motivated I enclose an extract from his calculations below.

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The Summer Milky Way

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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.

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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.

Clear skies.

2019 Star Stories And Urban Astronomy Dates

I’m delighted to announce the schedule of events for both the Star Stories Programme at Abriachan Forest and the Urban Astronomy evenings at the Merkinch Local Nature Reserve.  Some of these events may be subject to late change so please check back and keep tabs on my Highland Astronomy Facebook page for more details.  I’ll also post Eventbrite links for bookings here and on social media around a month prior to each event.

Star Stories at Abriachan Forest

Now entering its third year, Star Stories returns with another captivating programme of family friendly stargazing and storytelling events.  This year will see the erection of a wooden henge and sundial at the Abriachan site to compliment the program’s leaning towards ancient and observational astronomy.   Further ahead, and as a result of overwhelming feedback, we’re looking to fund an on-site video telescope to enhance the binocular observing and expand the outreach of the events via live streams.  Star Stories is in collaboration with Abriachan Forest Trust and part funded by the STFC’s Spark Award Scheme.

Location:  Arbrichan Forest (A Dark Sky Discovery site)

Oct 5th at 8pm – Ancient Astronomy.  Kicking off the observing season with a night of stargazing, storytelling and ancient astronomy learning (indoor and outdoor).  In collaboration with the Highland Archaeology Festival.  Astronomy outreach:  Stephen Mackintosh.  Storytelling: Clelland McCallum

Nov 23rd at 7pm – Dark Sky Man.  The first ‘Dark of the Moon event’ and another chance to let special guest astronomer and author Dark Sky Man (aka Steve Owens) guide you across the night sky.   Guest astronomer  Steve Owens.  Storytelling: Clelland McCallum .

Dec 11th at 7pm – ‘Astronomy from the Moon:  studying the universe from our nearest neighbour’ is a talk delivered by Professor Martin Hendry of Glasgow University, joining us again in the forest classroom.  We’ll have a full Moon this evening allowing us to observe with video telescope and binoculars.  Guest speaker:  Prof. Martin Hendry.   Astronomy outreach:  Stephen Mackintosh

Dec 21st at 7pm – Winter Solstice Special with guest storyteller and author John Burns.  Celebrate the longest night and the slow return of brighter days with a special dark sky Solstice special with our first ever guest storyteller, author John Burns.  We’ll also have outdoor stargazing and astronomy guiding (weather permitted) or a solstice inspired astronomy talk.  Guest storyteller:  John Burns.  Astronomy Outreach:  Stephen Mackintosh

Jan 10th 7pm – Eclipse Special.  A special night on the astronomy of eclipses with an opportunity to observe a live penumbra eclipse of the Moon via binoculars and video telescope.  Astronomy outreach:  Stephen Mackintosh.  Storytelling: Clelland McCallum

Feb 29th 7pm – KISS Astrophotography talk with guest Eric Walker from the Highland Astronomical Society.  Plus stargazing and astronomy outreach with astronomer Stephen Mackintosh.   Guest speaker: Eric Walker.  Astronomy outreach:  Stephen Mackintosh.  Storytelling: Clelland McCallum

March 21st 7pm – Equinox Special with a talk from local photographer Claire Rehr.  Plus stargazing and storytelling with Stephen And Clelland. Guest speaker: Claire Rehr. Astronomy outreach:  Stephen Mackintosh.  Storytelling: Clelland McCallum

The Glasgow Science Centre crew will also return in May for more hands on workshops.

 

Urban Astronomy Evenings at the Merkinch Nature Reserve

Since finding a permanent base of operations at the Sea Cadets Hall in Inverness, the Merkinch Urban Astronomy nights have attracted a growing number of participants.  This year we’ll be inviting some guest speakers and continuing our format of indoor astronomy talks with the additional option of walks to the nature reserve for live observing.  This programme is delivered in partnership with Caroline Snow and Friends of the Merkinch Local Nature Reserve.

Evening meetings:  Sea Cadets Hall, 44 Kessock Rd, Inverness IV3 8AJ.

October 3rd at 8.30pm – Saturn Special.  Opportunities to stargaze and observe Saturn from the local nature reserve and perhaps the setting Moon next to mighty Jupiter.  Guiding by local astronomer Stephen Mackintosh.  If sky conditions are poor we’ll stay indoors for an indoor presentation on Saturn.

November 7th at 8.30pm – Moon Special.  Come and observe the bright waxing gibbous Moon from the grounds of the Merkinch nature reserve.  Indoor Moon talk if skies are poor.

December 19th at 8.30pm – ‘A Telescope isn’t just for Christmas’.  A special Christmas event on getting started with observing, what to buy, what to avoid, where and when to observe.  With local astronomer Stephen Mackintosh.  Outdoor stargazing from the reserve if conditions are clear.

January 16th at 8.30pm – Supernova Special with guest speaker Dr Anthony Luke of UHI talking about the incredible science and chemistry behind exploding stars.  Opportunities for stargazing from the local nature reserve if conditions are clear.

February 20th at 8.30pm – Aurora Special with guest photographer Graham Bradshaw.  Graham will discuss aurora, how to find it and photograph it.  He’ll also share some of his amazing photographs and videos.  Opportunities to observe from the nature reserve if time and weather permits.

March 12th at 8.30pm – Venus Special.  With Venus now a beacon in evening skies we’ll have a special talk on the planet with astronomer Stephen Mackintosh,  Plus opportunities to observe it, and the stars, from the local nature reserve.