As you are no doubt aware NLC are visible when the sun is between 6-16degrees below the horizon. I was thinking that it would be pretty useful if there was an 'app' or little peice of software that could, given an observers location, produce times for when the sun is 6-16deg below the horizon, and hence when NLC should be visible.
Now with a pen and paper and plenty of time this is something I could work out manually for a single location, but I thought it would be really good to have an 'electronic' version that anyone could use. Unfortunately my pc skills don't stretch far enough to be able to write the code etc to do this, so I guess this is a plea; is there any of you out there who know how to and would be willing to do this, or, alternatively, does anyone know of any existing applications that can calculate this???
If this is something that can be done it would be a really useful tool for the people using this forum... Anyone???
Hi Len, thanks for that, that's the sort of thing I had in mind, will have a play around with it.
Hi John, my reasoning for this is that you only have to look at the geographical distribution of members of this forum to see that people are looking for NLC from a variety of latitudes, now the time when the sun is between 6 & 16 deg below the horizon is going to be different for them all. Just thought it might be a helpful gizmo for people to know the exact time from their position.
Hi John Murrell here - I have 3 NLC calculation spreadsheets on my website (http://www.johnmurrell.org.uk/nlc.html) as follows:
Calculation Spreadsheet Shows how far the Sun is below Horizon from May till August to show you times NLC are possible.
NLC Now Shows Sun Altitude & Azimuth in real time to allow you to know when to stop observing and go to bed ! ( or go to work in the morning)
NLC Record Sheet Allows you to record your result and shows the Sun’s Altitude & Azimuth to put in your records –Manual Update via ‘F9’ (recalculate) key. Should start on first day of month. Save as Excel Macro Enabled file
Tips: All require Excel with Macro’s enabled. Enter your latitude & longitude before use Calculation spreadsheet may take a minute or so to calculate
Hope these help your observations - nothing seen from here just South of London yet.
There is also a PDF file of a lecture I gave to the SPA and Croydon AS on NLC this year. Interesting that we had a proffesional met office meterologist in the audience who despite taking hourly observations from RAF stations had not seem them.