Night Sky Quality Monitoring Report

Craters of the Moon NM, Idaho

Inferno Cone, September 11, 2004

To effectively manage any resource, we need to know what we have and what we've lost. "Light Pollution", the brightness in the nighttime sky due to artificial light, can be seen from almost every park. The NPS has developed a system for measuring sky brightness to quantify the source and severity of light pollution. This system, developed with the assistance from professional astronomers and the International Dark-sky Association, utilizes a research-grade digital camera to capture the entire sky with a series of images. Data clearly shows that even remote national parks are not immune from stray artificial light. Sky brightness is measured in astronomical magnitudes in the V-band, abbreviated as "mags". The V-band measures mostly green light, omitting purple through ultraviolet and orange through infrared. The magnitude scale is a logarithmic scale. A difference of 5 magnitudes corresponds to a 100x difference in brightness. Lower values (smaller or more negative) are brighter. Further information on astronomical magnitudes can be found on this Sky and Telescope webpage. Data images are shown in false color, with yellow, red, and white corresponding to brighter sky and blue, purple and black corresponding to darker sky.

A more detailed explanation is available.

Category	Details	Image
Park	CRMO	Narrative: Site on summit of Inferno Cone, 0.3 mile walk from parking area, OK for Public or telescopes. 5% clouds, increasing, only one data set obtained in early evening. High clouds to southwest accentuating light dome of Twin Falls. Southern horizon flat, north slightly blocked by mountains. Seeing very good, transparency good. Sky very dark at zenith, airglow seems less than usual, many light domes to east through south through southwest along I-15 corridor. No light dome extends more than 10 degrees above horizon.. Cars on highway 93 briefly point headlights directly at the site coming from the east.
Site Name	INFERNO CONE
Longitude	-113.55211
Latitude	43.44332
Elevation (m)	1891
Date (UT)	September 11, 2004
Time Start (UT)	6:11:31
Data Quality	Good
Equipment	SBIG 50mm f/2 6048
Observers	D. Duriscoe, C. Duriscoe
Air Temp (°F)	63
Rel Humid (%)	13
Wind Sp (mph)	5
CCD Temp (°C)	-20
Exp (seconds)	15
Bortle Class	3
ZLM	7.0

SKY BRIGHTNESS DATA

Data Set Number	Time (UT)	Extinction Coefficient (mag/air-mass)	Std Err Y Extinction Stars (mags)	Zenith (mag/sq arc-sec)	Whole Sky (mags)	Sky Above 20° Altitude (mags)	Brightest (mag/sq arc-sec)	Darkest (mag/sq arc-sec)	Links to Sky Maps
1-Start End	6:11:31 6:32:09	0.172	0.078	21.50 21.65	-7.06	-6.47	20.39	21.95	PAN HEMI

LIGHT DOME DATA

City	Distance (km)	Azimuth	1st Data Set Brightness (mags)	Image
Arco	29	43.8	2.90
Idaho Falls	123	86.9	-1.55
Pocatello	108	125.2	-0.48
Burley	102	190.2	0.38
Twin Falls	123	217.5	-0.73
Total			-2.98