The Satellite Sundial

[Keeping Up]

When I'm looking for an overnight mooring, I often need to know the approximate direction of the satellite so that I can avoid the major obstacles (tall trees, houses, etc) and then I will be able to watch TV that evening. When the sun is shining I use its direction to help, which led to me devising this diagram. If you print it out on an A4 sheet of paper you can tell the approximate direction of the satellite by turning the paper around until the current time of day is pointing towards the sun. If you can use the shadow of a vertical object it will be even more accurate. On several occasions I have found the satellite this way without any further assistance.

 

There are two diagrams - one for BST and one for GMT - so you can print one on each side of the paper. You may need to right-click on each of the images below and save the pictures to your PC first.

 

 

 

 

 

 

I think I've got the GMT and BST clock thing the right way round - please let me know if I haven't (or if I've got anything else wrong in drawing them up). I hope you find them useful; but remember of course that they only work on sunny days!

 

Edited for spelling

Edited July 15, 2008 by Keeping Up

[BlueStringPudding]

Excellent! I'm so glad you posted this on here. Gonna print them right now. However I might not get home till after dark tonight... do they work by moonlight too?

 

Nah, seriously, I'll try them out tomorrow after work. I'm tired of having to walk 20ft away from any boat for my compass to stop spinning like a mad thing!

[Machpoint005]

I've just spent ten minutes trying to work out whether it's the right way around. I think it is!

 

It's like trying to find north using a wrist watch (spot the former Scout). You have to pretend your timepiece is set to GMT first!

[bottle]

They are the right way, BST/DST is one hour fast to GMT.

[Keeping Up]

I just thought I'd round this topic off by adding a footnote that the Mark 2 sundial, much more accurate than the one above, is now available in this topic.

[rachel12]

Wow, This is very useful information but you have not replied the question that it will work in moonlight or not? I also try it and I took the print of it. Thanks for sharing.

[nb Innisfree]

We've always used Nicholsons guide to get a rough bearing then twirl dish a bit until we get strongest signal

[MartinC]

The Easy Find system means that you just turn the dish until the red light on the arm thing changes to yellow and then green. For the exotic you can set the system to find whichever satellite you want. No expensive installation costs and no compass work

[Keeping Up]

Wow, This is very useful information but you have not replied the question that it will work in moonlight or not? I also try it and I took the print of it. Thanks for sharing.

 

No it is strictly a sundial, in which capacity it has definitely been proved to work very well and be very accurate. I know that at least 200 people have downloaded it from the web site, including a number of caravanners, and I've not had any complaints yet - apart from the obvious one that it doesn't work in heavy cloud cover.

 

I did think about trying to make a moondial, but the 3-dimensional maths needed to do the calculations defeated me very quickly indeed.

Edited January 6, 2011 by Keeping Up