NLC Visibility calculations

[johnm]

Hello everyone,

I have a Noctilucent cloud page on my website at www.JohnMurrell.org.uk. There are a couple of spreadsheets that observers may find useful.

The first is a revision of a spreadsheet that was on the site last year it now changes the year automatically. This spreadsheet shows the Sun's altitude for all the nights of the northern NLC season so you can see how far the Sun is below the Horizon on a particular date and time. The colour of the figures changes to show the best times when the Sun is between -6 and -12 degrees below the horizon and also the times the sun >12 degrees below the Horizon. You can use the spreadsheet to work out what time you need to get up to see the morning NLC !

I suspect when the Sun is 6 degrees below the Horizon it may not be dark enough to see NLC but this may be due to abnormal refraction recently. I have seen aircraft con trails lit when the Sun is supposed to be 6 deg below the horizon.

The second is a new spreadsheet that shows the Sun's current Altitude & Azimuth updated every 15 secs. The displayed altitude also changes colour during the best observing times as above.

Both spreadsheets require the macros to be enabled when they start. Also you need to enter your observing position and time zone.

Regards

John Murrell
.

[mesospheric]

John, it's a great effort, but I have to confess, I prefer to use something like Stellarium planetarium, which shows other key information - like the accurate rendition of twilight and the positions of stars in the relevant part of the sky. All up to individual perferences, of course!