Hi Dudes
Got a basic question .... What's a CAA term that I see in this and other astronomy forum?? hahaha
What's CAA?
-
cloud_cover
- Posts: 1170
- Joined: Mon Jul 12, 2010 6:08 pm
- Favourite scope: 94.5", f/24 Ritchey-Chretien Reflector
- Location: Restaurant At the End of the Universe
Civil Aviation Authority. UK Governing Body regarding civilian flight and aerospace issues, together with the EU sets on of the 2 world standards in Pilot Licensing standards, the other being the FAA of the USA.
Aircraft are a very important factor in astronomy as their sheer numbers often obstruct our view of celestial bodies and cause trails and aircraft shadows when taking long exposure photos. Also, since shining a laser at one is an offence, its very important to know where and when they fly hence the concern with the CAA
Aircraft are a very important factor in astronomy as their sheer numbers often obstruct our view of celestial bodies and cause trails and aircraft shadows when taking long exposure photos. Also, since shining a laser at one is an offence, its very important to know where and when they fly hence the concern with the CAA
DON'T PANIC
-
cloud_cover
- Posts: 1170
- Joined: Mon Jul 12, 2010 6:08 pm
- Favourite scope: 94.5", f/24 Ritchey-Chretien Reflector
- Location: Restaurant At the End of the Universe
JUST KIDDING!!!!!! 
You mean CA, Chromatic Aberation, which is usually a blue halo surrounding brighter objects such as planets, the moon and brighter stars. These occur then different wavelengths of light come to focus at different focal lengths - usually at the focal plane of most refractor telescopes blue light is still somewhat unfocused resulting in a blue halo around bright objects.
A lot of research and work has gone into creating refracting telescopes that have minimal of nil chromatic aberation but well corrected designs (called APOs, for apochromatic, usually triplets, meaning they have 3 objective lenses) can be very expensive indeed. Be aware though some manufacturers will call their telescopes "APO" when they are not really true APOs. Ask the more senior chaps around here for more advice
CA is not an issue with reflectors since the don't use refracting lenses.
Don't worry too much about this - personally I find SOME CA to be visually pleasing on brighter stars - makes them look more like diamonds. But that's a personal opinion.
You mean CA, Chromatic Aberation, which is usually a blue halo surrounding brighter objects such as planets, the moon and brighter stars. These occur then different wavelengths of light come to focus at different focal lengths - usually at the focal plane of most refractor telescopes blue light is still somewhat unfocused resulting in a blue halo around bright objects.
A lot of research and work has gone into creating refracting telescopes that have minimal of nil chromatic aberation but well corrected designs (called APOs, for apochromatic, usually triplets, meaning they have 3 objective lenses) can be very expensive indeed. Be aware though some manufacturers will call their telescopes "APO" when they are not really true APOs. Ask the more senior chaps around here for more advice
CA is not an issue with reflectors since the don't use refracting lenses.
Don't worry too much about this - personally I find SOME CA to be visually pleasing on brighter stars - makes them look more like diamonds. But that's a personal opinion.
DON'T PANIC
