sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery

 

Sail-World.com : Red lights for good night vision - but why?

Red lights for good night vision - but why?

'Good night vision from red lights in cabin or cockpit'    .

Red lights in the cockpit or cabin are there to protect your night vision - that critically important sense to achieve the very best outcome when scanning for objects on the horizon at night. But have you ever wondered just why the red lights achieve this? Read on...

The back of our eye, called the 'retina' detects light and allows us to 'see'. The retina is made of of 2 types of structures, cones and rods.

The cones are responsible for our normal daytime vision. Cones detect both the wavelength (color) and intensity (brightness) of light that goes into our eyes and passes that information to our brain.

The rods are responsible for our 'night adapted vision'. Rods do not detect wavelength (no color), but are very sensitive to intensity (brightness) of light. They pass on only shades of gray to our brain. They only work at very low light intensities (dim light), are most sensitive to light at about 500nm (turquoise/cyan), and are blind to red light (around 620nm).

If you are walking around under daylight and you see the world in a kaleidoscope of colors, you are using your cones to see with. If you are walking around under starlight and the whole landscape appears as shades of gray, you are using your rods to see with.

The last thing you really need to know about the rods is that it takes some time for them to work after moving from bright lights to a dim environment. Usually it takes about 15-30 minutes for them to work at 100%. However, even a fraction of a second of bright light will cause the clock to reset and you may have to wait another 15-30 minutes for your night vision to be back to 100%.

This is why it is very important to have a red light in your cabin to switch on when you wake for your next night watch. It will prevent you arriving in the cockpit temporarily blinded.
.....................

Interesting mail from reader:


Sender: Graham Shelley-Jones

Message: A good article and interesting reading to those that want to know why? My comment is as a colour-blind person, relax, it is not contageous, who is often amused by these articles. Those of my 'affliction', and there are many, just sigh and wonder when the worlds designers will start to cater for 'us'? 'We' see the light spectrum differently and red is a real bastard when we are bombarded with it. 'We' are also not equally affected, and so there is more than one colour that affects our perceptions. Give me a blue, give me a black, give me a yellow, but please don't give me a red. Particlularly, please don't give me a mix of red/green/amber to sort out, unless it is in the familiar traffic light format. I am content to know that 'my lot', of colour-blind cohorts, are unique in some applications and professions. Did you know that 'we' were employed as Camouflage Spotters' during WWII, and that we make great colour inspectors in Panel Beating shops? It's OK girls, you can't catch it, as it is only the males that are afflicted.




by Lee Mylchreest

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=88811

1:02 AM Fri 23 Sep 2011 GMT






Click here for printer friendly version
Click here to send us feedback or comments about this story.


Related News Stories:

19 Mar 2014  How to anchor and 'never utter a word'
10 Jan 2014  Cruising seminars from Fremantle around the coast to Cairns
10 Dec 2013  Cruising seminars from Fremantle around the coast to Cairns
04 Dec 2013  Remove the mast, check the rigging - at home!
24 Nov 2013  Young Endeavour seeks sailors between 16-23 years for 2014 voyages
06 Nov 2013  Use This Simple 'Speed and Power' Sail Trim Secret!
29 Oct 2013  How to anchor and 'never utter a word'
22 Oct 2013  Ocean cruising classes from Maryland - a great way to start
21 Oct 2013  How to stay put in a blow - the good oil.
15 Oct 2013  Cruising seminars from Fremantle around the coast to Cairns
MORE STORIES ...

News - USA and the World







































International Moth Worlds: Rashley ahead as Aussies close in by Mark Jardine / YachtsandYachting.com,




















International Moth Worlds - Mothballed on day 4 + Video by Mark Jardine / YachtsandYachting.com,




Gladwell's Line: A change of direction needed in the America's Cup *Feature by Richard Gladwell/Sail-World.com/nz,




Red Bull 49erFX: First look at the Olympic sailing venue at Rio
Fuerteventura Kiteboarding Grand Slam - Classic conditions on day 3
NYYC Race Week Part II images by Rolex/Daniel Forster
Drowning or electric shock? What you need to know to help save a life
BIC Techno 293 Worlds 2014 - Day 1
Six Metre European Championship - Blazing sunshine on opening day
National Sailing Hall of Fame to present Lifetime Achievement Award
International Moth Worlds: Greenhalgh and Rashley tied at the top
PWA Pozo World Cup - Fantastic finale determines winners
Six Metre Class British Open Championship - Llanoria and Valhalla win
Anna Tunnicliffe set to compete at the CrossFit Games
America's Cup: Oracle Team USA holds foiling camp at Wangi SC
Volvo Ocean Race: Abu Dhabi OR completes double Atlantic crossing
Volvo Ocean Race: Team SCA has a 'pull through day' off the Canaries
No tiller sailing - how to steer using just the sails + Video
International Moth Worlds: Three bullets in a row for Greenhalgh
U.S. Junior Women’s Singlehanded Championship - Sophia Reineke wins
BIC Techno 293 Worlds 2014 - Day 0 Opening
Fuerteventura World Cup - Slalom action highlights day 2
2014 Governor's Cup - Sam Gilmour of RFBYC victorious again
Farr 40 West Coast Champ - Skipper Alberto Rossi leads Enfant Terrible   
Flying Dutchman World Championships - Magyars are the Masters   
Final day shakes up standings at Cape Panwa Hotel Phuket Raceweek   
2014 -15 Volvo Ocean Race: Team Alvimedica pushing towards Southampton   
NYYC Race Week - Saving the best for last   
VX One North American Championship - Chris Alexander commands   
2014 Cape Panwa Hotel Phuket Raceweek - Waiting game on Day 3   
International Moth Worlds: Thunderstorms delay racing on Day 1   
Fuerteventura World Cup - Impressive tricks on day 1   
2014 Governor's Cup - Two former winners in the finals   
America's Cup: Iain Murray explains reasons for Australian withdrawal *Feature   
Wilson and Roble remain number one match racers in U.S.   
2014 ISAF Youth Match Racing World Championship - Set to start   
PWA Pozo World Cup - Moreno twins dominate home spot   
ISAF Youth Worlds - Record breaking regatta in Tavira + Video   
Melges 32 European Championship - Robertissima remains out front   
Farr 40 West Coast Championship - Italians take one-point lead   
Melges 32 European Championship - Day 3 images by Carlo Borlenghi   
New York Yacht Club Race Week - Marstrom 32 fleet off to anxious start   
Melges 32 European Championship - Day 3 images by Max Ranchi   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL WAS US
LocalAds   DE  ES  FR  IT