How to draw a rainbow? (Slight P link)

[Fat Tone]

We want to paint a giant rainbow on our son' bedroom wall. Not being very good at arty things, I want to do it right, technically.

So how do I do it? I'm guessing I need to anchor my pencil a certain distance from the wall and draw an arcwhilst somehow maintaining a constant angle?

The Parhelia link comes from going to Ask Jeeves and typing "how do I draw a rainbow?". One of the links leads to a very detailed explanation of sundogs.

Cheers

T.

[Dogbert]

You can try using a broom stick with a pencil at it's end.
Just make seven 2 - 3 inch marks apart from each other starting at the base of the stick (the axis side), each time use the next mark as the axis point for the stick.

Use a nail or something as an axis and draw 8 arcs for the seven colors.

Just my 2 cent idea. I'm sure you can come with better ones

[TdB]

how about:
tie a string(with a length = radius of rainbow) to the spot where the center of the rainbow should be, tie the other end of the string to a pencil, and draw a half cirkel, while keeping the string tight.

if you want an elipse-shape, you can tie a short string between 2 centerspots?() and then tie the pencil string to the string between the centerspots, but not tight, the pencil string should "slide" along the centerspots-string, and then draw while keeping the pencil-string tight.

[Fat Tone]

You know, sometimes the answer is just too damn simple!

Thanks guys. I just need to have the ends of my rainbow high enough up the wall that the centre of the circle the rainbow will be formed from can fit on the wall. I was originally thinking that I wouldn't have that option.

I'll post a piccie when it's done


I guess the next question is how many degrees should my arc cover to maintain the correct 'aspect ratio'?

T.

[Rakido]

Originally posted by Tony Andrews
I guess the next question is how many degrees should my arc cover to maintain the correct 'aspect ratio'?

T.

42 degrees

Rakido

[Greebe]

@Rakido LOL

[Fat Tone]

I promised to show the results...

[Dogbert]

Nicely done !