Night Sky Quality Monitoring Report
Sequoia/Kings Canyon NP, California
Moro Rock, September 28, 2005
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 | SEKI |
 Narrative: Evening begins very hazy, lots of moisture in the air. As night progresses, inversion layer drops below summit, downvalley wind brings clearer and drier air. Lights of cities to west somewhat dimmed by haze, however illuminate the summit on its west side strongly, ruining night vision unless hidden from view. Air very steady, faint stars easily seen near zenith. Western sky very bright to 45 degrees above the horizon. M33 barely visible near zenith, gegenschein barely visible near midnight. Fantastic seeing, excellent observing site for that reason alone. However, do not recommend the summit for public or telescopes, possibly Wolverton parking lot or Wuksachi?
|
| Site Name | Moro Rock | |
| Longitude | -118.76505 | |
| Latitude | 36.54419 | |
| Elevation (m) | 2061 | |
| Date (UT) | September 28, 2005 | |
| Time Start (UT) | 3:32:18 | |
| Data Quality | Very Good | |
| Equipment | SBIG 50mm f/2 6084 | |
| Observers | D.Duriscoe | |
| Air Temp (°F) | 48.9 | |
| Rel Humid (%) | 71 | |
| Wind Sp (mph) | 6 | |
| CCD Temp (°C) | -20 | |
| Exp (seconds) | 15 | |
| Bortle Class | 4 | |
| ZLM | 6.8 |
| 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 |
3:32:18 3:53:14 |
0.194 |
0.043 |
21.38 21.24 |
-7.36 |
-6.66 |
19.59 |
21.85 |
PAN HEMI |
| 2-Start End |
4:31:28 4:52:25 |
0.181 |
0.041 |
21.35 21.33 |
-7.45 |
-6.74 |
19.50 |
21.72 |
PAN HEMI |
| 3-Start End |
5:30:36 5:51:36 |
0.169 |
0.048 |
21.59 21.65 |
-7.44 |
-6.71 |
19.36 |
21.77 |
PAN HEMI |
| 4-Start End |
6:29:47 6:50:37 |
0.156 |
0.042 |
21.72 21.77 |
-7.41 |
-6.65 |
19.16 |
21.82 |
PAN HEMI |
| City | Distance (km) |
Azimuth | 1st Data Set Brightness (mags) |
Image |
|---|---|---|---|---|
| Los Angeles, CA | 272 | 173.1 | -2.00 |
 |
| Bakersfield | 133 | 189.4 | -2.05 | |
| Porterville | 58 | 203.9 | -2.76 | |
| Visalia | 55 | 244.2 | -4.39 | |
| Fresno, CA | 96 | 286.2 | -4.24 | |
| Total | -5.15 |