IDA-Colorado section news and upcoming events
Monthly IDA-Colorado pow-wows during Open House nights at U of Denver's historic Chamberlin Observatory 

8-10pm weather permitting including 2014 Nov.1, Dec.27, 2015 Jan.24, Feb.28, Mar.20 etc.


Lighting codes/regulations in your area (2014): http://www.iescu.org/lightingcodes.htm


				2015 ...  communications with colorado.ida AT gmail.com
Dark Sky Meter phone app: http://www.darkskymeter.com/ 
Map of DarkSkyMeter app readings including Colorado: http://www.darkskymeter.com/map/ 
and the original and best SkyQualityMeter: http://unihedron.com/projects/darksky/ 

20150225 - setting aside legalities for a moment, there may be an opportunity to help find light pollution solutions with the use of DRONES.  Many property owners are unaware of the magnitude of escaped light, especially uplight.  However, a short video obtained in the evening by drone overflight could be a literal eye-opener...

20150121 - talk on LED lighting brought out the fact that Los Angeles has changed out their prior streetlight equipment in favor of LED luminaires - with resulting reduction in light escaping upward - see final frames in this pdf report: http://photos.state.gov/libraries/finland/788/pdfs/LED_Presentation_Final_June_2013.pdf 

20150115 - link to CDOT rules as adopted for Nighttime Video LED signage & see chron entries below.

20141024 - letter in support of dark sky designation for Colorado towns of Westcliffe and Silver Cliff:

Dark Skies, Inc., P.O. Box 634, Westcliffe, CO 81252

    On behalf of the Colorado Section of the IDA, I am writing in support of the nomination of the adjoining Towns of Westcliffe and Silver Cliff as the first International Dark-Sky Community in Colorado.  Approval will make these towns the highest in altitude of any designated.  It has been an inspiration to be aware of the local group, Dark Skies, that has been working diligently to reduce the light pollution of Colorado’s  wonderful “nightscape” of star-filled night skies. The protection of this valuable resource to both towns has been a 15-year journey of which both Dark Skies and the residents can be proud.  These towns serve as a crucial counter-example to the wanton and relentless destruction of dark skies occurring across much of Colorado.

    Viewing the nightscape from an isolated refuge and dark location like these Colorado towns can provide a transformative experience of unparalleled beauty.  This sense of awe, that most of human history has experienced, has been lost to urban dwellers.  Only through protection of remaining areas like Westcliffe-Silver Cliff, can residents and visitors continue to marvel at the view.  Because economics matter in success of this preservation effort, designation is key to promoting “eco-tourism” - which can become an important part of the towns’ economic success.  In parallel, the long-term protection of the nightscape is dependent on the towns’ enforcement of non-polluting, shielded exterior lighting language in their building ordinances.  Designation can help provide additional incentive for these towns to act to protect their special resource.

    Certification of the Towns of Westcliffe and Silver Cliff will also reduce the impact of light pollution on migrating and resident bird populations that use various aspects of the night sky for their instinctive behaviors.  It will also reduce the negative effects on the natural circadian rhythm of creatures, including humans, that are important for long-term health.  Urban dwellers need to wake up to these impacts on all living things within the zone caused by their excessive lighting and related pollutions.

    I am a proud supporter of Dark Skies’ certification effort for the Towns of Westcliffe and Silver Cliff.  It will reduce the impact of light pollution and I consider it as a transcendently  valuable example to all communities in Colorado to think and follow this path of light pollution solutions.

Astronomically,   Dr. Robert Stencel, Coordinator - Colorado section of IDA

                * * * * *

20140906 - In Cities Across Texas, Activists Battle Billboard Companies
Text: http://www.npr.org/2014/09/06/346153394/in-cities-across-texas-activists-battle-billboard-companies  
Audio: javascript:NPR.Player.openPlayer(346153394, 346299218, null, NPR.Player.Action.PLAY_NOW, NPR.Player.Type.STORY, '0')   

"The Highway Beautification Act will be 50 years old next year. As envisioned by Lyndon and Lady Bird Johnson, it was supposed to protect the natural landscape from billboards.
"Ever since its passage, scenic activists and billboard companies have been at war over the views along American highways. The outdoor advertising industry says its signs are informational, and helpful to local businesses. Open-space advocates call them "sky trash" and "litter on a stick."
"The battle continues today. You can see it on the roads of Texas, where more than 350 towns and cities have banned new billboards — but billboard companies continue to push for taller and more technologically advanced signs. etc...

Notes related to the CDOT/electronic signage policy review meeting, 8-28-2014:  

    (1) strategically, although CDOT and State policy presently only cover "off-premise" electronic (LED) billboards, rules made at this level may be adopted by local jurisdictions to encompass the anticipated flood of similar signs "on premise" appearing at local businesses in your town.

    (2) how bright is an LED billboard capable of being?  Brightest in the region thus far are metro Denver signs adjacent to I-25 north at 58th street, with the brightest being 1,000 "nits" ... just how bright is that?  converting to magnitudes per sq.arcsecond (units of the type measured by a Sky Quality Meter), that equates to FIVE mags/sq.arcsec; for comparison, your laptop screen at max brightness might be about 60 "nits" or about 8 mag/sq.arcsec; for comparison, metro Denver SQM readings have been in the 16 to 18 mag/sq.arcsec ballpark, which equate to 3% to 10% of one cd/m2. 

    (3) if you see a overly bright electronic billboard at night, here's how to make an effective complaints: if it seems to be advertising an adjacent business, it may be an on-premises sign governed by local rules - contact the planning department or engineer of the town or city involved; if the sign appears to not be associated with an immediately nearby business, it may be an off-premises sign governed by state regs, in which case you can call the CDOT hotline, 303-757-9485, or online at dot AT state.co.us .   

    (4) Colorado section of the IDA believes documenting problems helps in their solution, and so we extend an invitation to submit your smart phone images of overly bright signs at night to the email address  colorado.ida AT gmail.com and be sure to include date, time, address and any information you have about the problem (e.g. glare or other disabling aspect).  We will try to share the digital info with appropriate authorities for resolution.

28 August 2014 -- CDOT & illumination levels from LED billboard signage - the latest source of glare for drivers and contributor to skyglow. Outdoor Advertising Rules Representative Group Meeting (rescheduled) to be held on August 28, 1pm, 4201 E. Arkansas Ave., Denver -- for more info , contact Mary Nevans, Rules Admin, 303-757-9723, maryfrances.nevans@ state.co.us.  Copies of related documents can be requested.

12 August 2014 -- email from Larry Barrett/ consultant with Scenic Colorado Inc. -- 

"I have left voicemail messages with Northern  Colo. Astronomical Society.  Denver Astronomical Society and  Colorado Springs Astronomical Society with Alan Gorski.  I left them messages this morning on the meeting plans of CDOT, encouraging them to register, and inviting them to call me.  If you have any connections with them and want to reinforce my message, please do.

"One objective of us should be for CDOT to not rush to judgment on nits vs. footcandles and levels, unless of course they agree on the use of nits and a level of 100 at night. I doubt they will adopt that.  However, I am concerned they may stick with their preliminary judgment in favor of footcandles and 0.3.  If they are still leaning that way I hope to persuade them to do more research, do not accept the limited research they have done, based largely on what has been submitted by the billboard industry and me.  If the rest of CDOT is using nits for highway lighting design, then why not for roadside advertising?   If CDOT has not done field testing of luminance and illuminance, it would seem good regulatory practice would be for CDOT to conduct independent research of existing static and electronic signs.

Thanks for your participation.

Larry Barrett, President, Barrett Consulting Associates, Inc., P.O. Box 60429, Colorado Springs, CO 80960, 719-634-4468 (o); 719-964-0825 (m)



11 August 2014 --Westcliffe and Silver Cliff applying for Dark Sky Community Certification --

 I just wanted to let you know that our Dark Skies group will be going public next month with our plans to seek IDA Dark Sky Community certification for Westcliffe and Silver Cliff (we are calling ourselves "The Cliffs" for this application).  As you may know our group has been quite active working on local dark skies projects for a number of years.  We believe we can already meet most of the IDA requirements for certification as a result of these activities.  Our primary hurdle will be to get the two communities to enact lighting ordinances to meet IDA requirements.
Westcliffe has hired a "Main Street Manager" to help with the community's economic development efforts.  Dark Sky Certification is expected to be one of this manager's first projects.  We will be giving a presentation to the Westcliffe Town Council at their meeting on September 8 to let them know what we are doing.  Once our plans are made public at this meeting I wouldn't be surprised if the press or others might contact IDA (and perhaps you as IDA coordinator) for more information.

As IDA's State Coordinator I am not sure how much you are involved in the certification process.  However, we certainly would like to solicit your support and guidance as we go through this.  I know some parks are working on certification but I do not know if any other Colorado communities are actively working on it at this time.

I will be serving as the IDA contact for our group.  Our current Chairman in Jim Bradburn.

If you would like to discuss this more I would be glad to call you (please let me know the best number to call).  You can also call me anytime at (719) 285-4480 or reach me by email.  Thanks, -- Steve Linderer, slinderer@gmail.com 

20 April -- Internatio nal Dark Sky Week, 20-26 April, 2014

April (all): Astronomers Without Borders Global Astronomy Month & World at Night (TWAN) 5th International Earth & Sky Photo contest
April 20: World Night in Defence of Starlight, the annual celebration of the Declaration in Defence of the Night Sky and the Right to Starlight 
April 20: Start of GLOBE at Night's April campaign
April 22: Earth Day
A page is up on the IDA website describing the Week on: http://www.darksky.org/ resources/109-international- dark-sky-week


20 Feb 2014 – astronomy talk by Dr.Bob at Lakewood Country Club breakfast meeting of the Rotary Club,

and mini-meeting of the Colorado section of IDA: Dr. Bob, Leslie Clark & Rick Angell.

Feb.11, 2014 -- From: Nancy Emerson fnemerson AT comcast.net - Feb 11

To colorado.ida AT gmail.com, Amee AT darksky.og

[update 2/20: from john@darksky.org

Thank you for contacting IDA about Chimney Rock.  My name is John Barentine and I manage the Dark Sky Places Program, having taken over for Amee Henning who left IDA last fall.

I am the IDA Chapter Leader for Santa Barbara County, CA. We recently visited the new Chimney Rock National Monument near Pagosa Springs. Based on the name, I was not sure what to expect but discovered it was an archeoastronomy site. It is located in a very dark part of Colorado and the visitor area looks like it is dark sky compliant, too. While there I talked with the volunteer in the very small visitors center and then with our volunteer tour guide. I mentioned to both of them the IDA Dark Sky Park awards and suggested they apply. They were a bit hesitant and explained that it was the volunteers who had pushed through the site's designation as a national monument in 2012. Now 18 of the volunteers are the interpretative "staff" from May-September (and beyond for schools wanting tours) so they are feeling overwhelmed with work. I learned that the change to a monument has not yet been accompanied by additional funds so the US Forest Service is operating it on a shoestring with the volunteers also continuing to do significant fundraising. As you can imagine, I am very impressed by these volunteers as well as this amazing monument. It is such a unique site that it would be a jewel in IDA's recognized parks. I am wondering if you might be able, over time, to work with them on an application. Please visit the monument's website, if you have not already visited the monument itself, to learn why I found it so unusual. (www.fs.usda.gov/detail/sanjuan/specialplaces/ and www.chimneyrockco.org).

Reply: Hello Nancy, Amee:

Thanks for the contact about Chimney Rock and its potential as a Dark Sky heritage site.  The loosely organized Colorado section indeed may have members in the Four Corners area who could personally lobby with USFS and others toward that goal.  If Amee could share with me a current membership roster, we could share your suggestion and enlist the extra help, along with what I can do from the distance of Denver to Chimney Rock.  Perhaps a conference call would be a useful next step as well.

--Dr.Bob Stencel, Denver Univ Astronomy Program and Coordinator, Colorado section IDA

New contacts:

Triana Lockaby wrote: I am in the North Denver area. There are so many street lamps and company signs, and the football stadium lit up all the time, that it seems redundant to use headlights when driving at night.

Are there any proposals to address the night lights in Denver?

Reply: Hi Triana. Metro Denver has criminally excessive amounts of badly done lighting that produces glare, trespass and skyglow. Denver city has enacted some progressive lighting regulations, but those have extensive exemptions for businesses – Denver building code details start at denvergov.org: http://www.denvergov.org/tabid/436473/Default.aspx# and


Other towns in metro Denver have assorted building code requirements – see http://www.iescu.org/lightingcodes.htm

You might call your city planning department and ask what can be done about wasteful lighting practices in your area, and see what might be next steps. Key to it all is educating anyone who will listen that we can be smarter about how we use nighttime lighting. Hope this helps.

Recent IDA newsletters, press releases, etc: Join IDA!





Solutions?  Get details at: www.darksky.org

"The sky, our common and universal heritage, is an integral part of the environment perceived by humanity. Humankind has always observed the sky either to interpret it or to understand the physical laws that govern the universe. This interest in astronomy has had profound implications for science, philosophy, religion, culture and our general conception of the universe". Proclamation of 2009 as International Year of Astronomy. UNESCO General Conference. Paris 2005.
“Persons belonging to future generations have the right to an uncontaminated and undamaged Earth, including pure skies; they are entitled to its enjoyment as the ground of human history of culture and social bonds that make each generation and individual a member of one human family.” Our premise: EXCESSIVE SKY GLOW OVER CITIES IS THE MANIFESTATION OF LESS THAN IDEAL ENGINEERING AND MANAGEMENT OF OUR ELECTRICAL AND LIGHTING RESOURCES, MOST OF WHICH CAN BE CORRECTED.Universal Declaration of Human Rights for Future Generations. La Laguna, 1994. Website: STARLIGHT: International Initiative in Defence of the Quality of the Night Sky as Mankind’s Scientific, Cultural and Environmental Rights.

0. Compilation of regional night sky photometry HERE
1. Denver City and County studying new lighting regs... details available at website DENVERGOV.ORG and search on Lighting Regulations
2. Useful links to Colorado city, county, state lighting regs:
Colorado IESNA and select link to LIGHTING CODES, near end of left column.


LIGHT POLLUTION refers to wasteful and excessive electric lighting that blocks our view of the night sky.

Light TRESPASS and GLARE refer to unwanted and harmful lighting.

During 2001, the Colorado Legislature agreed and modified state law to address these issues: SECTION 2, ARTICLE 82 OF TITLE 24, COLORADO REVISED STATUES IS AMENDED BY THE ADDITION OF A NEW PART TO READ: PART 9, OUTDOOR LIGHTING FIXTURES.

Astronomers are NOT AGAINST SAFETY, but are very worried about destruction of the night sky by lighting that shines uselessly into the sky, wasting money and depriving everyone of their cosmic birthright, not to mention causing inferior sleep and melatonin disruption. Badly aimed light also produces trespass nuisance, and disabling glare -- especially for older people.

The simplest solution also saves money: add a shield on top of new lighting, to direct all of the light toward the ground where it is needed.

Also, the use of motion sensors and timers reduce the cost of lighting to only when it is really needed.


2005 Dec: Pueblo County adopts stricter lighting regs. Link: http://www.co.pueblo.co.us/planning/planning_cases/TA%202005-003/Final%20Proposed%20Outdoor%20Lighting%20Regulation.pdf
2005 Nov: Arvada City adopts new lighting code language, www.arvada.org
2005 Sept. Regional IDA workshop, Yellowstone Nat Park
2004 Sept. 17 WORKSHOP, Frisco, Colorado:
Topics/Speakers included:
The vanishing Colorado night sky, Robert Stencel; Practical solutions for light pollution, Nancy Clanton; Crime prevention through environmental design, John Minor; Lighting Ordinance process case study, Joani Matranga & Jill Peterson

You might find local lighting codes and regs interesting: STATE and COUNTY and CITY lighting regs and proposals

House bill 1160 as introduced Colorado Legislature, Jan.2001; Rationale; and how to contact your elected state reps here in Colorado:

as well as the in-force DOUGLAS COUNTY regs:

The 1999 TEXAS LAW signed by George W. 'hissef': (& search for 1999 HB 916)
and the Texas Effective Outdoor Lighting Council

and City, County and State regs controlling lighting, NATIONALLY:

A recent composite of EARTH AT NIGHT from space (dmsp):

and how to contact your elected state reps here in Colorado:

News about growth and energy issues:
Page 1 double headlines on growth and energy, check archives for Dec.21,2000.

A few terms defined, from the Dark Sky Association homepages:

GLARE: The 8th edition of the IESNA Lighting Handbook (1993) defines glare as the sensation produced by luminance within the visual field that is sufficiently greater than the luminance to which the eyes are adapted to cause annoyance, discomfort or loss of visual performance and visibility. It stands to reason, then, that any good outdoor lighting design will minimize glare. If the light source itself is more apparent than what it is illuminating, then you have bad lighting.

Light TRESPASS is light that is distributed where it is not wanted or needed. Streetlighting, for example, should light streets and sidewalks, not shine into second floor bedroom windows or illuminate rooftops. Also known as spill light, light trespass occurs whenever light shines beyond the intended target and onto adjacent properties.

UPLIGHT is, in the truest sense of the word, wasted light. Light that goes directly up into the night sky is "lost in space" and serves no useful purpose. Uplight is the bane of astronomers and the occasional stargazer because atmospheric scattering artificially brightens the night sky, making distant celestial light sources difficult or impossible to see. Uplight often results from light fixtures which also produce glare and light trespass.

And from NEMA: FULL CUTOFF fixtures are those that allow "no light at or above a horizontal plane located at the bottom of the luminaire" (lamp plus fixture).

Contact Prof. Stencel with questions. Visit the DU Observatories: Chamberlin and Mt.Evans.
Keywords: light pollution, glare, trespass, melatonin, astronomy, astrophysics, astronomy, astrophysics, observatory, infrared, telescopes, universe, planets, stars, comets, Denver ...

For more information, visit the International Dark Sky Association homepage at www.darksky.org.