Spark and Perl go looking
Why have you got a stopwatch?
Because this star blinks, and how fast it blinks tells me how bright it really is.
You can SEE how bright it is.
I can see how bright it looks.
A candle far off looks like a firefly up close.
Oh.
So the difference is how far away it is.
That is how we measured our whole galaxy.
With a stopwatch.
Yes — a few degrees from Vega.
The whole cycle repeats in about half a day.
You can see this from almost anywhere — but not the very far south.
Where to find RR Lyrae, and when
Where the Earth is clear, it climbs high in the sky. The darker it gets, the lower it stays. Where it is black, it never comes up. No shading at all: it does not matter where you live.
What do I need to see RR Lyrae?
Binoculars with 10× magnification show it, if you rest them on a fence or a wall.
You will need a chart. This one is for the child who likes the measuring more than the looking.
A 150 mm telescope does not make it better — this is about comparing brightness, not about magnification.
Space
Eyes, binoculars, or telescope?
Read on
Go and look