by Pat Browne
January – Good Month for Night Sky Conservation
Observing the Night Sky in the middle of January is not an easy thing to do – due to the extreme cold and amount of snow in the Mississippi Valley Conservation Area. It can also be cloudy, with snow squalls coming up unexpectedly. The challenges are not necessarily mitigated by the fact that you have more night-time to try and do some observing. This is true particularly when the skies are ablaze with artificial light. Thanks to the combined efforts of Mississippi Valley Conservation, the Municipality of Mississippi Mills and the Royal Astronomical Society of Canada, we are blessed with a Night Sky Conservation program that helps everybody learn how to keep the lighting down so that darkness that we need at night for rest and re-creation are preserved.
Good Neighbour Lighting Program – Tips for Preserving Natural Darkness for Night
The following tips help residents learn to preserve darkness for night-time by shielding lights and keeping the wattage and glare down. This helps limit light trespass so that lights are shielded from shining into a neighbour’s window.
Reason for the January Season…
And now for some explanation on why we have so much extra time to observe the Night Sky:
The month of January is the time of year when the earth’s orbit speeds around the sun, and is closest to it. This year, January 4, 2014 marked the day of Perihelion – when the earth is at the point in its elliptical orbit that is the shortest distance to the Sun…. However this has practically no effect amount of time that the Sun radiates the earth.. nor the intensity of solar radiation incident on the Northern Hemisphere. It is odd to consider that the earth is closest to the Sun in its orbit in JANUARY, but for the Northern Hemisphere, the tilt of the axis away from the Sun is the significant factor that causes the Sun to rise late, set early and spend a lot of time below the horizon. This effect produces less solar radiation as the Sun’s rays hit the Northern Hemisphere at a lower angle, lowering the amount of heat supplied. So for Canadians, perihelion is only cold comfort! Because the Sun never rises very high in the sky in January, and because we have so many more hours of darkness, our closest approach to the Sun has negligible effect on the amount of solar flux on the earth’s Northern Hemisphere.
Low Sun Angle and Sun Below the Horizon
Darkness for Night – Healthy Need to Preserve it
Since stargazing during this month has been extremely difficult, we may consider getting some more sleep. So if a good night’s sleep is in order, we need to ensure that the night is not confused with the day, to keep our diurnal patterns healthy. Darkness for sleeping helps restore our chemical balance, and ensures we follow natural body rhythms. We need to ensure that the lighting at night is subdued, low wattage and shielded so that it does not glow up in the sky and atmosphere causing light pollution.
Bright, glaring Outdoor Lighting compromises our sleep when it disturbs our darkness with bright lights that mimic daylight. Travelling to an evening concert from Mississippi Mills to Ottawa, the glare in the night sky was extra-ordinarily bright – as glare from unshielded high intensity lights.
Outdoor lighting in our area maintains a proper balance of adequate lighting without producing glare and light pollution. Consider these factors for producing good quality visibility without disturbing night vision or sleep…
- Shielded and Flat-Glass Outdoor lights – commonly called Full Cut-Off lighting
- Low Intensity of the light : 70-100 Watts saves Energy! (NOT high wattage > 300 Watts)
- Nature of the light: Subdued warm colour lighting (NOT full-spectrum light white light)
We now know that in order to restore the amount of melatonin in our bodies, we need to reduce the amount of glaring bright lights shining up in our skies.
“Light/dark (L/D) cycles are the environmental cue for the entrainment of our circadian rhythms. The neuro-hormone melatonin (MLT) plays a major role in this process as it indicates the dark period of the 24 h cycle. Therefore the disruption of MLT secretion due to Light at Night (LAN) exposure may have a negative impact on daily rhythms and seasonality of our physiological and immune systems. ” – Haim and Portnov
So one way to appreciate our darker night sky, is to appreciate the fully shielded lights that help ensure we catch a good nights sleep during those long winter nights when the sun remains below our local horizon.
“The Town of Mississippi Mills is proud to be a leader in the preservation of our night sky. The Town of Mississippi Mills recognizes that the night sky is a precious natural resource that needs protection. The quality of our night sky is vastly superior to that found in most areas of the province. It is a defining element of rural, small town character that is under threat and in many respects is no different than our farmland and our wetlands.
Thanks to the Good Neighbour Lighting Program in Mississippi Mills we can ensure there is Darkness for Night at bedtime – particularly for long winter nights.
We can thank our Lucky Stars that we have preserved a healthy Night Sky Environment in Mississippi Mills. Stay tuned for details on the Mill of Kintail NightSky Course, Friday nights in April .