Help Us Hunt Darkness
The Norwood Dark Sky Community’s measurement program needs help! The group that will designate us Dark Sky, The International Dark Sky Association, insists we prove it by making actual measurements of how dark it is out here. We’re ok with that because we know it will be a slam dunk!!
After winning a grant from Paradox Community Trust, NDSC purchased two Sky Quality Meters (SQM) replacing those we had on loan thanks to Black Canyon Astronomical Society and its President, Bryan Cashion. An SQM measures the “brightness of the sky”, which is the light from surface, airborne, and heavenly sources that have been scattered and reflected by dust and moisture in the atmosphere. At night light from the surface is the major source so the brightness of the sky on a moonless night indicates the amount of surface light pollution. The brighter the moonless sky, the more light pollution and the fewer stars you can see. During the day the sky is so bright because of scattered and reflected sunlight that you cannot see stars, even though they are there.
Our SQMs meet IDA standards and have a twenty-degree field of view, which covers a good chunk of sky. They measure sky brightness in units that are hard to explain in this short article so check the FAQs tab for more details. Our SQMs have a range 16 to 22 units. Urban centers and full moon nights have readings around 16, moonless, dry high desert locations like Norwood approach the limit of 22. Most of our recent readings on Wright’s Mesa are greater than 21.50. I’ve recorded 21.77 on Deer Mesa and 21.88 has been recorded at Pinon Wood Ranch!! That means you can see very faint stars, invisible to the naked eye, using high-powered telescopes.
NDSC has developed an SQM observation program that is so good IDA has asked us if they could use it internationally! That program can use some help.
When I first saw an SQM it looked easy to operate. Point it at the sky, push the button, wait for the result. That is about it. Except: a) you have to get there (five observation locations from Redvale to about 7 miles SE of Norwood); b) no bright lights, so you work with a red headlamp; c) observations are needed at the cardinal points (N, E, S, W) 45 degrees above the horizon and one at zenith (straight up); d) the SQM is quirky, requires a 10 min adjustment to local outside temperature and not much contact with hot human hands (we wear gloves); e) for a measure of variation we want 3 observations at each cardinal point and zenith; f) a sky condition assessment is needed as well as surrounding light sources; finally, e) observe the SQM temperature (available with another button push) and outside temperature. Not easy.
So we need help recording the data. Right now the observer has to get there, note the time and temperature, make a sky condition/surrounding light assessment, and take three separate observations per cardinal point/zenith; all the while in the dark managing footing and orientation. Help with recording data plus companionship for safety would probably cut the time at each observation location by half thus increasing the number of places we can visit on one night.
In winter you can easily make SQM readings before midnight because the sun goes down early. That’s the good news. The bad news is that it is usually really cold. In summer it is a lot warmer but the sun goes down much later putting observers on the graveyard shift, often not starting til 10:30 or 11. Weather forecasts and current weather are checked as well as specialized satellite images that show cloud cover at night and atmospheric water vapor before an observation team is launched. Teams can be updated in the field from a “command” post if communications exist.
Why is this important? Because we’d like to get this Dark Sky Designation stuff over in the next year. Results of this SQM Project are required. We only have about a week toward the end of the month to do this; the nearly moonless, new moon period. And it isn’t always clear out here.
Get in touch with: Bob Grossman (grossman@colorado.edu), Creighton “Woody” Wood; norwooddarkskycommunity@gmail.com ) and Val Szwarc (vszwarc@aol.com ) to help us out. Thanks!!!
Heavenly Outlook
It’s time to start saying goodbye to Orion as he sets in the west along with other constellations. Auriga, for one, is following right behind the Hunter. Auriga the Charioteer got its name from the group of stars that look like the helmet of a charioteer. If you trace a line from Orion’s feet to his shoulders and continue, you should see five bright stars making the helmet. The brightest is the sixth brightest star in the sky, Capella. Why is this one in particular so bright? Well, it actually isn’t just one star. It is a star system made up of two binary star groups. Binary stars are two stars that orbit each other; in this case, there are two binary star groups less than a light year away. When looking at “Capella” 42 light years away, that spot is actually four stars packed closely together. Also, while looking in this direction and following the two fainter bottom stars of Auriga, a couple of degrees south, you will be looking exactly opposite the center of our galaxy. The “anti-center” is shown in the picture right next to the constellation. Also in the area, towards the south, is two faint lines of stars forming the two twins of Gemini, but they might not be visible for a few days, because the moon will be in between them. Following that same direction, you should be able to also spot Procyon, the major star in the Canis Minor following Orion.
The anticenter near Auriga