Skip to content
Search for:
Join
Donate
Contact
My IES Portal
IES Bookstore
Sign In
MENU
MENU
MY IES
MY IES Portal
(Members Only)
MY IES Profile
MY IES Contacts
MY IES Communities
MY IES Discussion Posts
MY IES Blogs
MY IES Transactions, Registrations & CEUs
Community Help/FAQs
Video Tutorials
About
About the IES
Mission, Vision & Beliefs
History
Board of Directors
Governing Documents & Policies
Annual Reports
Press Releases
IES In the News
IES Staff
Careers at the IES
Contact Us
Membership
About Membership
Join the IES
Sustaining Members
Emerging Professionals
Renew Membership
IES Member Directory
(Members Only)
IES Manufacturer Directory
IES Progress Report
About Sections/Districts
Find a Section
Section/District Forms and Documents
(Members Only)
Section Communities
(Members Only)
Society Awards
Grants & Scholarships
Career Center
Events
IES Calendar of Events
Annual Conference (AC)
Registration
Speaker/Paper/Poster Submissions
Program
Hotel/Venue/Airfare
Exhibitors
Conference Sponsors
Conference EP Program
IES Leadership Forum
Committee/Contact
Archived Presentations
(Members Only)
Progress Reports
(Members Only)
Street and Area Lighting Conference (SALC)
Registration
Program
Hotels/Venue/Airfare
Exhibitors
Committee/Contact
Illumination Awards (IA) & Gala
IES @ LIGHTFAIR
IES Virtual Research Symposium
Other Industry Events Calendar
Lighting R&D Workshop
Advanced Education Fly-in (AEFI)
Maritime Regional Conference
IES Events Photo Gallery
Standards
About IES Standards
List of Standards
(IES Lighting Library)
Committee Reports
The Lighting Handbook
Nomenclature and Definitions
RP-16-17 (Free)
Jointly Published Standards
IES Standards in Public Review
Committees
About IES Committees
Join a Committee
Non-Technical Committees
My Non-Technical Committees
Technical Committees
Committees Resources
Open Committees
My Technical Committees
The Standards Committee
Advisory Panels
Research
About IES Research
Current Projects
Past Projects
Events
Research Symposia
Research Workshops
Annual Conference Paper and Poster Sessions
Portal Open Now
Publications
LEUKOS
100 Significant Papers
Symposium Proceedings
Annual Conference Proceedings
2016 Strategic Research Plan
FIRES Forum
Policies and Submission Information
Opportunities
Grants
Visionary Challenge
Education
About IES Education
Education Supporters
Speakers Directory
(Members Only)
Facilitator Directory
(Members Only)
Lighting Industry Certifications
Education FAQs, Forms & Guidelines
Educational Webinars
Register for Webinars
Archived Lighting Education Webinars
(Members Only)
Archived Lighting Standards Webinars
(Members Only)
Archived Section Webinars
(Members Only)
IES eLearning Portal
Educational Series
Indispensable Lighting Series
Lighting Education Facility Showcase
Trailblazers & Icons
(Members Only)
Vintage Recordings
Educational Podcasts
Forces of Change (with Mark Lien)
Lights of the Round
Architecture for Light
Trailblazers & Icons
FIRES Podcast Series
Face-to-Face Materials
Fundamentals of Lighting
Intermediate Seminars
Post-Fundamentals Courses
IES Lighting Ready Reference App
(Free Download)
Teachers of Lighting Workshop (TOLW)
LC Study Group
Outreach
About IES Outreach
Alliances
Policy Briefs/Documents
Position Statements
Letters to Public Officials
Outreach News
LD+A
About LD+A
Advertise
LD+A Editorial Calendar
LD+A Writer's Guidelines
Subscribe
Current & Back Issues
(Members Only)
Hot Topics
LD+A Featured Content
Trending Articles
Projects in Videos
Project Photo Gallery
IES in LD+A
Illumination Awards Recipients
The Emerging Professional
2019 Lightfair Wrap Up
2019 Progress Report
2019 Manufacturer Directory
circadian
5 July 2018
2018-07-05
Post navigation
[12.8.1.4] Variations with a cycle of approximately 24 hours.
« Back to Definitions Index
