Urban Astronomy Inverness

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The formation of a young protostar following the collapse of a previously inert dust cloud

We had a great turnout for March’s Urban Astronomy session last week at the Sea Cadet’s Hall in Inverness.  The indoor presentation massively benefited from our new giant screen, expertly erected by Robbie (pictured below).  Here’s a selection of slides from my presentation on naked eye observing and the life of giant stars.

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Robbie putting the final touches to our new giant screen for indoor astronomy presentations and virtual sky guiding

Topics covered:

– Naked eye and binocular observing
– Satellites: Iridium Flares and ISS
– Colour, temperature and mass of stars
– The Hertzsprung-Russell diagram
– Protostar formation from dark nebulae
– Main sequence burning and final fate of stars
– White dwarfs, supernovae, neutron stars and black holes.

As ever there were some superb questions during and after the talk.  Stay tuned for upcoming events as myself and Caroline roll out the program.

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In the simplest terms stars behave like black body radiators with colour linked to their surface temperatures.

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The brightest stars in the night sky can be close – like Sirius – or giant stars very far away (eg. Betelgeuse, Rigel, Deneb).

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The HR diagram.  An elegant and reliable tool for describing the evolution of stars from main sequence burning into their final stages of life

The Quadrantids Meteor Shower 2019

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The Quadrantids meteor shower will peak on the night of Jan 3rd/4th

Although not normally singled out as a major meteor shower, the 2019 Quadrantids will peak under the darkness of a new Moon, offering the best chances of seeing an abundance of shooting stars if you can get away to a suitably dark location under favourable skies.

Like the Geminids, the Quadrantids are not produced by the debris from a comet, but by a large asteroid.  In this case asteroid 2003EH1 which orbits the Sun every five and a half years.

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An asteroid – 2003EH1 was discovered by Peter Jenniskens and astronomers of the LONEOS programme in Arizona

The time to begin looking up will run from January 1st until the 6th.  However rates will be low in general over this wide period.  For the best spectacle try and head out over the narrow peak of the shower, after midnight on January 3rd, when for a few hours the shower can theoretically produce between 50-100 meteors per hour, but only under ideal conditions.

If you’re observing close to midnight at Inverness latitudes (57 degrees) the radiant will be about 22 degrees high.  Therefore a more realistic estimate would be 20-30 per hour.  Stay out later and the radiant will rise higher increasing the theoretical rate.  If you’d like to know more about the technical considerations when estimating visible meteor rates check out this excellent blog post by Steve Owens.

The rough radiant for the Quadrantids is the constellation Bootes, although you don’t need to look in this direction to see them.

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Remember you don’t need to look at the radiant when viewing a meteor shower

Observing the Quadrantids

You don’t need any special equipment to view a meteor shower, in fact binoculars or telescopes will just narrow your field of view. Grab a deck chair or camping mat and a warm blanket, prepare a hot drink, wrap up warm and lay out under the darkest conditions you can find. It’s an excellent activity to do alone or if you have children they’ll love an excuse to get outside for some after dark play.

Put away any lights or bright mobile phone screens and simply look up and wait. Remember it takes up to 30 minutes for your eyes to fully dark adapt and any exposure to bright lights will start the process all over again. If you need a light, red leds or touches are best for preserving you night vision.

For optimal viewing, head out late at night after the Moon sets or in the darkness of the pre dawn sky., when the radiant is highest in the sky.

Photographing the Quadrantids

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If your have a DSLR camera and tripod, or a suitable phone app like NightCap, you could try capturing some meteors with this rough guide.

  1. Firmly attach you camera to the tripod.
  2. Disable autofocus and manually focus at some bright stars (make them as small and pin point as possible in your viewing screen)
  3. Set an ISO range somewhere between 1000-3000 depending on the capabilities of the sensor.  Mid 1000s is a good middle road.
  4. Turn off noise reduction or you’ll get big delays between each shot.
  5. Point your camera at a high and clear part of the sky.
  6. Shoot long exposures ranging from 10s to 30s, or simply use a remote shutter to take manual exposures.  Note:  don’t go crazy with very long exposures or you’ll get amp glow from the sensor.
  7. Take lots and lots of shots and be patient!

If your camera has a time-lapse feature you can automate the shooting process and tell the camera to automatically take 30 second exposures over a long interval.  Just watch out for dew forming on the lens if conditions are cold.  Some hand warmers stuffed into a sock wrapped around the lens will solve this particular issue.

Good luck and clear skies!