A few weeks ago the topic of “the Moons possible Occultation of Neptune - 6th November 2008″ came up at my local Astronomical Society meeting.  It was thought that Neptune may be Occulted or may Graze what we see as the edge of the moon.

I decided to see what Stellarium though about this and my finding are that Stellarium predicts that it will graze the surface of the moon and not be occulted by the moon.  I then asked myself the question “Is software like Stellarium capable of confirming one way or the other whether this occultation will take place and if so to what degree?” no offence meant to the writers and fans of Stellarium – I love the product and as you read on you’ll see how I found it to be very accurate indeed.

I then got thinking that occultation, grazing, or no occultation what-so-ever may depend on your position on Earth.  So, I re-configured Stellarium to a location in London and ran a simulated time covering the evening of 6th November and found there was no occultation and no grazing.  I then switched locations to Glasgow and after running the simulation again I find that there is an occultation.

I didn’t give it much more though (as other things began to occupy my mind) and this blog post remained in the “Unpublished” queue.  Until I read about a similar article in the latest SPA magazine (Oct to Dec 08 page 43), and read about the Graze Line.

A Graze Line maps a line across Earth that is in effect the termination point between where you will see an occultation and where you will see no occultation.  Use Stellarium and fast forward your time to 6th November ‘08 to see if your location is on the Graze Line and if not how far away you are.

This particular Graze Line runs from south west (what looks to be St Austell) up through South Wales, East Midlands, Yorshire, and eventually to Whitby.  I live in Yorkshire (Rotherham) so am lucky enough to be on (or very close to) the Graze Line!  So, clear skies permitting I may get to see this event.

Until the next post… Clear Skies!

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