Northern Colorado Observing Overview
Written in response to questions from an out-of-state website visitor ...
You would likely be
thrilled by the number of clear days and the transparency. It's not unusual to
see Pikes Peak about 120 miles away on the south horizon. The transparency
makes the Milky Way a tangle of glowing knots and voids.
My thumbnail advice to you would be to look at other sites if you plan to look
at planets routinely, or be ready to travel. The seeing gets disrupted by the
peaks of the Northern Front Range, so you can get improvements going in about
any direction a few hundred miles from here. With the caution that the wind
picks up a lot about 60 miles north.
I would suggest that you review the Seeing Map in the Clear Sky Clock. You will
see patches of stable air move in from the West, sometimes stall for days over
Nevada/Utah, then get disrupted in our area. You can also watch stable patches
track across Ariz. - NM - TX - Okla. No luck for us, usually.
I've done my best to catch Mars, Jupiter and Saturn the last few years with an
18" Newtonian-Baader binoviewer-TMB Supermonocentrics, on an equatorial
platform, and on the average we get subarcsecond seeing a couple nights a
month. The highest mountain peaks are supposed to be better, but access is
limited. For example, Mount Evans Road is snowed in October to Memorial Day,
but Prof. Bob Stencel of the University of Denver is able to catch laminar flow
at the peak on many summer nights. I had promising looks at Mars there in 2003,
hampered by steady 20 mph wind. Cherokee Park is about the edge of reasonable
darkness, and it will gradually deteriorate as the region grows. At least the
city and county are moving to preserve open space in that area, a plus. The
Cache La Poudre River Canyon is a national treasure.
Here is a summary of a typical year:
Dec-Jan: If we get below 0 F, it's then. A bit of snow, sometimes days of
clouds, but some clear skies almost every week. A few days of good seeing,
usually. Some 60 degree F daytime highs are typical. February is similar but
trends warmer. Mountains are cloud magnets in winter, so we usually head to the
plains 40 miles for clearer skies, better seeing and 20 degrees warmer. Wind
can be oppressive.
March-April-May: The cloudiest quarter, usually. Still can observe a few days
here and there. Spring breakers return to find cars buried in snowdrifts, but it
melts within a few days. Tent flattening wind can be intense. Good seeing can
be hard to come by. May, the trees are leafing out, still pretty cloudy,
thunderstorms are common. Foothills can count on snow accumulation in April,
sometimes May. Many dirt-road mountain passes still closed by snow through May.
June-July: Access to higher mountain roads is opening by then. Common daily
pattern: clear morning, clouds mid afternoon, thunderstorms in evening,
mountains clear around midnight, the plains clear a couple hours later. I avoid
the plains in the summer due to hail and mosquitoes. Pretty short nights,
though, truly dark about 10 to 1030 pm MDT and getting twilight at 0330 it
seems. Can get a window of good seeing around midnight and dawn. A dome of
high pressure is common over Nev. - UT then, they can get a week+ of good seeing
while we are denied on the fringe of it.
August: One of the best months. Still having monsoon pattern but more clear
days typically, and nights are getting longer. Mountains not terribly cold at
night yet. Some decent seeing can almost always be had, but transparency is not
guaranteed because fire season can be upon us by then. Transparency is affected
by wildfires in California-AZ-NV in bad years. Oregon farmers seem to burn
their fields every year.
September-October: September seems a bit cloudier, moderate temps, seeing less
stable. October seems drier again. A few nights with a great look at Mars in
2005. Combination of moderate temp, Sun, fall color make early October a time
to see the mountains. Seeing can be good a few days. Frequently the first snow
arrives for Halloween but is gone in a few days.
November: Colder and cloudier again without much snow here. Mountain passes
snowed in. A good month to travel elsewhere. Possible to catch a good night on
the plains, but wind can be hairy.
With no constraints on where to live, I'd be investigating options around Salt Lake City, Ruidoso NM,
Las Vegas NM, Jack Newton's astronomer's development by Portal Arizona,
Flagstaff AZ to Tucson AZ corridor, the region around MacDonald Observatory in
Texas. I believe even the Western Slope by Grand Junction CO has more frequent
nights of adequate seeing than we do. We do have lots of pleasant sunny days,
mountain vistas, skiing & biking opportunities, college town activity, and
Denver for more metro pursuits. So if I moved, my family would disown me.
Dan Laszlo
Email name*: Laszlo_D
Broken links or errors - email*: webmaster Content suggestions - email*: web-edit
* Email links hidden from spam webbots by Tyler Akins' javascript mailto_encoder
(add "@ncastro.org" to the email name if the link is not displayed)
Updated: 03-Mar-2009