Denver University astronomy professor, Dr. Bob
Stencel
In Collaboration with the staff of Gates Planetarium,
Denver Museum Natural History [DMNS]
(c) 1997 – present...
Contact us directly
with your questions
Tienes
una pregunta de astronomia?
Denver is blessed with 2 fine facilities: GATES PLANETARIUM at the Denver Museum of Natural History, located in City Park, at 2001 Colorado Boulevard, and the historic CHAMBERLIN OBSERVATORY of the University of Denver, located at 2930 East Warren Avenue, SE Denver. Call (303) 871-5172 for schedules.
GATES PLANETARIUM features a variety of programs for all ages, from star lore to the latest astronomical results. Call 303-322-7009 for current schedules.
DU's historic CHAMBERLIN OBSERVATORY [ http://mysite.du.edu/~rstencel/Chamberlin/] features an operating 20 inch aperture Clark refractor. Public nights are held on Tuesday and Thursday evenings (for reservations visit website: http://www.thedas.org/ReservationFAQ.html or call 303-871-5172 for reservations). Also, the Denver Astronomical Society hosts free Open House nights monthly on the Saturday near first quarter moon phase, weather permitting. The observatory also accommodates evening astronomy classes – see http://mysite.du.edu/~rstencel.
Frequently
asked about:
SHORTEST/LONGEST
DAYS
METEOR
SHOWERS
FULL
MOON NAMES
STAR
NAMING
YOUR
FIRST TELESCOPE...
DID
YOU FIND A METEORITE?"
What
can be done about this damnable LIGHT POLLUTION?
and more!
Our usual recommendation is to start simple, with binoculars and a tripod. You can see the moons of Jupiter, craters on the moon and many Messier objects.
You didn't mention whether you are from the Denver area, but if so, the best new and used telescope store in the region USED TO BE S&S Optika (CLosed Nov.2015 after 43 years). IF you can postpone til the new year, you can visit one or more of our observatory open houses at DU's historic Chamberlin Observatory, 2930 E. Warren Ave., 7-10pm on most first-quarter moon Saturday evenings - call 303-871-5172 -or- visit twitter.com/Chamberlin_Obs for updates. There, members of the astronomy club display their various portable telescopes, WEATHER PERMITTING. It's a great way to see a variety of telescopes in action, talk with owners about likes and dislikes and generally get acquainted in a no-cost way. An online tutorial about choosing and using a telescope, from a reputable source, can be found at: http://www.skyandtelescope.com/astronomy-equipment/telescope-buying-guide/ Hope all this helps! Back to Question List
Have you found a meteorite? Unless you
personally saw it land, not likely, but check for meteorite
identification pages on the web. A good one to start with
is:
http://meteorites.wustl.edu/meteorwrongs/meteorwrongs.htm
Thanks for your inquiry. Meteor shower watching can be fun, but a
good location and patience are required.
LEONIDS peak during the
overnight Nov 17/18, depending a bit on the year. Unfortunately, the
average rate of Leonid meteors is very low - under 30 per hour. This
shower has very rarely shown extra bursts of up to 100 or even 1000
meteors per hour - but these have been predictable and associated
with the earth passing near the source comet.
Some great info
webpages::
http://cloudbait.com/science/showers.html
http://cloudbait.com/science/meteors.html
http://cloudbait.com/science/perseid2011.html
http://meteorshowersonline.com/perseids.html http://meteorshowersonline.com/leonids.html http://seds.org/Maps/Stars_en/Fig/leo.html
WHEN AND WHERE TO
LOOK: Meteor showers are named after the constellation from whence
said meteors appear to radiate. In the case of the Perseids
[Aug.11/12], the constellation Perseus rises to the northeast AFTER
MIDNIGHT, with meteors appearing to radiate away from it. For
the Leonids [Nov.17/18], the constellation LEO rises well AFTER
MIDNIGHT in November, toward the EAST. Meteors appear to originate in
and around LEO and can cross a good part of the sky - up to 90
degrees. See the images at the cloudbait links, above.
Dress for
cold weather. Happy hunting!
NOTES ON THE NOVEMBER 1999 METEOR SHOWER: Leonids -- week of
Nov. 17th -- a possible 'storm' was forecast)
For results, view
plots at www.leonidstorm.com
NOTES ON THE NOVEMBER 1998 METEOR
SHOWER:
While a true storm of meteors didn't occur, the show was
very good: Gates Planetarium and DU teamed up and travelled about 20
miles east of Cherry Creek Res on Monday night -- Tues morning. It
was clear enough between midnight and 0230 for us to record a number
of fireballs on a wide-angle video system, plus count rates of about
60 per hour thru variable wave clouds. After 0230, the clouds became
dense enough that we could only occasionally see the very brightest
meteors lighting up the clouds at times. We gave up about 0500. The
S&T website (www.skypub.com) early reports suggests rates of
100-300 seen around the US. Asian rates varied from zilch to
thousands. After Tuesday night, rates seemed to be sharply lower.
Sadly, the 1999 event features bright moonlight.
OTHER REPORTS:
"I've received reports via the IMO network regarding Leonids
around the world. Briefly, most report a 100-300/hr peak between 0000
and 1200(UT) on the 17th (discounting, for now, a couple extraneous
1000-2000/hr reports from Switzerland). Bottom line: peak came
several hours earlier than predicted and contained numerous, bright
fireballs. --Dave Street, BVAA&LAS Back
to Question List
More about meteors, IN GENERAL: To observe,
look northeast after dark, esp. after midnight, unaided eye is best.
Next meteor showers (usual rates 20-40 per hour): Geminids peak
Dec.13; Ursids peak Dec.22 and Quadrantids peak Jan.3rd.
Annual variation in Leonid shower peak hourly rates
*1799Nov12,thousands 1930Nov16/17, 120 at peak
*1833Nov12/13, 100,000 *1932Nov17, 240 at peak
1866Nov13/14, 2500 1933-39 avg. 30 per hour
1867, 1000 with moon 1940s-50s, 15 per hour
1868, 1000 1961Nov17, 50 per hour
1869Nov14, 200 at peak 1962-64, 20-40 per hour
1870 on, 15 per hour 1965Nov16, 100 at peak
1898Nov14, 200 per hour *1966Nov17, 144,000 per hour!
*1899Nov14, 40 per hour 1967-69, ~100 per hour
1901Nov14/15, 400 per hour 1970-on, 15 per hour
1903 on, 15 per hour 1994Nov17/18, 75 per hour
1995: 50 @ peak
1996: 60 @ peak
1997Nov17: 150 @ peak
1998Nov16/17: 60-300 per hour reported over US
------------------------------------------------------------------------
*Radar observations 1998 Leonids from 16/11/1998 12 UT to 18/11/199812 UT.
* RAW DATA
In the following table, echoes are showed as function of duration. In
the second column of the table there are echoes with duration smaller
than 0.1 s; in the third column there are echoes with duration between
0.1 and 0.25 s; and so on.
Duration (seconds)
|0.1|.25|0.5|1.0|2.0|4.0|8.0| 16| 32| 64|128|256| tot
dd-mm-yy
16-11-98 12 | 10| 13| 15| 10| 3| 1| 1| 2| 1| | | | 56
16-11-98 13 | 10| 15| 11| 8| 5| 3| 2| | | | | | 54
16-11-98 14 | 27| 23| 20| 9| 12| 4| 1| | | | | | 96
16-11-98 15 | 13| 26| 14| 11| 5| 3| 4| | | | | | 76
16-11-98 16 | 12| 7| 5| 6| 5| 2| 1| | | | | | 38
16-11-98 17 | 19| 20| 15| 13| 3| 5| | 1| | | | | 76
16-11-98 18 | 35| 26| 15| 18| 5| 11| 2| 1| | | | | 113
16-11-98 19 | 31| 44| 34| 21| 6| 11| 2| | | | | | 149
16-11-98 20 | 53| 48| 35| 28| 20| 3| 1| | | | | | 188
16-11-98 21 | 31| 35| 15| 10| 11| 4| 1| | 1| | | | 108
16-11-98 22 | 60| 82| 32| 30| 24| 8| 6| 2| | | 1| | 245
16-11-98 23 | 47| 46| 27| 26| 7| 5| 8| 6| 1| 8| 14| | 195
17-11-98 00 | 25| 19| 10| 15| 14| 7| 2| 7| 3| 3| 21| 1| 127
17-11-98 01 | 6| | | 2| 2| 1| | 2| 2| 3| 33| | 51
17-11-98 02 | | | 2| | | 1| | | 2| 2| 33| 1| 41
17-11-98 03 | | | | | | | 1| 1| 1| 3| 32| 1| 39
17-11-98 04 | | | | | | 1| | | | 1| 28| 4| 34
17-11-98 05 | | | | | | | | | | 1| 33| 2| 36
17-11-98 06 | 4| 5| 3| 8| | 2| 5| 3| 1| 3| 34| | 68
17-11-98 07 | 3| 2| 2| 2| 4| 3| 6| 3| 3| 6| 31| | 65
17-11-98 08 | 10| 3| 10| 7| 5| 12| 4| 5| 7| 7| 21| 2| 93
17-11-98 09 | 22| 21| 12| 15| 10| 4| 8| 4| 15| 7| 13| | 131 *dmnh
17-11-98 10 | 30| 15| 20| 10| 14| 6| 6| 6| 4| 4| 3| | 118
17-11-98 11 | 22| 18| 13| 7| 9| 3| 5| 4| 4| 2| 3| | 90
17-11-98 12 |182|172| 99| 59| 32| 25| 7| 2| 3| | | | 581
17-11-98 13 |224|157| 88| 46| 40| 26| 4| 1| | | | | 586
17-11-98 14 | 3| 4| 4| | 1| 1| | | | | | | 13
17-11-98 15 | 3| 5| 1| 1| 1| 1| | 1| | | | | 13
17-11-98 16 | 7| 9| 7| 3| 1| 2| | | | | | | 29
17-11-98 17 | 6| 2| 3| 3| 1| 1| | | | | | | 16
17-11-98 18 | 14| 18| 13| 6| 5| 5| | | | | | | 61
17-11-98 19 | 27| 30| 16| 18| 13| 12| | 1| | | | | 117
17-11-98 20 | 55| 35| 35| 25| 14| 5| 7| 2| | | | | 178
17-11-98 21 | 47| 27| 21| 12| 16| 8| | 2| | | | | 133
17-11-98 22 | 78| 72| 48| 24| 18| 10| 3| | | | | | 253
17-11-98 23 |107|119| 58| 39| 29| 15| 2| 4| 1| | 1| | 375
18-11-98 00 |123|113| 68| 33| 27| 21| 9| 2| 2| 3| 1| | 402
18-11-98 01 |148|121| 73| 48| 36| 24| 14| 6| 5| 3| 3| | 481
18-11-98 02 |111|103| 56| 42| 30| 29| 17| 7| 3| 6| 7| | 411
18-11-98 03 | 94|101| 66| 39| 25| 24| 7| 6| 2| 2| | | 366
18-11-98 04 |114|103| 62| 47| 33| 19| 9| 6| 7| 2| 2| | 404
18-11-98 05 |135|102| 63| 44| 36| 15| 16| 6| 10| 3| 3| | 433
18-11-98 06 |110| 83| 62| 31| 19| 15| 8| 6| 3| 8| 5| 1| 351
18-11-98 07 |108|104| 59| 47| 33| 18| 10| 6| 4| 4| 4| | 397
18-11-98 08 |113| 91| 57| 37| 24| 15| 13| 11| 4| 2| 4| | 371
18-11-98 09 |122|120| 68| 52| 27| 19| 8| 6| 3| | | | 425
18-11-98 10 | 85| 95| 67| 55| 25| 14| 9| 4| 1| 1| | | 356
18-11-98 11 | 67| 61| 60| 44| 43| 22| 4| 9| 1| | | | 311
18-11-98 12 | 68| 64| 53| 39| 19| 24| 6| 4| | | | | 277
NOTE: In the morning of November 17th there was a peak characterized by
a large number of fireballs with very long duration echoes. This did not
allow the recording of meteors with small duration echoes, on account of
saturation effects. However, we would like to point out that in the first
hours of November 18th we recorded the predicted Leonid peak, but it was
characterized by a large number of small meteors.
We note also a peak between 12 and 13 UT of November 17th, with a huge
amount of evanescent meteors having duration less than 0.25 s.
This year is characterized by the presence of an unexpected peak (Nov.
17th) in addition to the known peak (Nov. 18th). We may suggest two
possible hypotesis:
1) non gravitational forces shifted the main peak?
2) a new zone of P/Tempel-Tuttle surface was active during its last
perihelion passage?
However, we stress that these are only first guess from raw data.
Further hypoteses can be made after a detailed analysis.
Cordially,
L. Foschini & G.Cevolani
Denver is blessed with 2 fine facilities: GATES PLANETARIUM at the Denver Museum of Natural History, located in City Park, at 2001 Colorado Boulevard, and the historic CHAMBERLIN OBSERVATORY of the University of Denver, located at 2930 East Warren Avenue, SE Denver. Call (303) 871-5172 for schedules.
GATES PLANETARIUM features a variety of programs for all ages, from star lore to the latest astronomical results. Call 303-322-7009 for current schedules.
DU's historic CHAMBERLIN OBSERVATORY [ http://mysite.du.edu/~rstencel/Chamberlin/ ] features an operating 20 inch aperture Clark refractor. Public nights are held on Tuesday and Thursday evenings (please call 303-871-5172 for reservations), plus the Denver Astronomical Society hosts free Open House nights monthly on the Saturday near first quarter moon phase, weather permitting. The observatory also accomodates DU Astronomy Classes.
Lunar water, like earth's water, may have been delivered with icy comets in the early years of the solar system. Earth's larger mass allowed us to hold on to a lot of this material, while the moon could not. So. lunar water deposits may be billions of years old, assuming its orbit and axis have remained stable... The nifty idea is that IF there is a permafrost on at least part of the moon, we can benefit from those raw materials already in place when it comes to spacetravel and occupancy. Plus, it'll help set up better chances for humans going to Mars, where similar situations exist. Back to Question List
Indeed, comets can be very friable (i.e. crubly), you have probably heard of the dirty snowball analogy. Comets are made up of frozen gases (carbon dioxide, water, oxygen, cyanide etc.), minerals and organic molecules. If a comet was large enough, and dense enough, to make it through the Earth's atmosphere and landed on the surface, then if the fall was witnessed, a sample of the comet could be taken. To my knowledge (and others) this has never happened. There is good reason for a comet not being collected. First, the gases would sublimate rapidly so you would have to be at the fall site almost immediately with a liquid helium dewar to keep the sample. Additionally, remember Tungusca (sp?) in Russia. There are theories that this was a comet that exploded in the Earth's atmosphere leveling trees for miles around. I suspect if someone had been near the site of the explosion immediately afterwards only small fragments of the comet would have survived, today of course there is nothing. Back to Question List
MORE: Scientists looking at the Earth's early development theorize that our oceans and the seeds for life on Earth came from the frozen water and organics in comets. More recently there has been controversy about satellite imagery of the Earth that has some mysterious black spots on it. Some think that these may be large very loose "snowballs" impacting the Earth's atmosphere. They are not strong enough to make it to the surface and break up in the atmosphere. The jury is still out on this one...
So, will we ever get to see what a comet is made of? Other that spectroscopic studies and space probe flybys there is a project for a comet sample return mission. Lockheed Martin is built the "Stardust" spaceprobe for rendezvous with the comet Wild 2. Check out the web page at http://stardust.jpl.nasa.gov/ Back to Question List
MORE: The final part of your question -would it frozen gases be considered a comet or an asteroid -they would be a comet. Back to Question List
Should we, on a global scale, attempt to dismantle this asteroid to test our ability to deal with an inevitable, more real threat? The dinosaurs were probably obliterated by an impact 65 million years ago by a modest sized asteroid or comet, and there is evidence for periodic disruption of the biosphere every few 100 million years.
Are we as a species up to the challenge of being able to prevent our own extinction from an asteroid? If we started today, we'd barely decide on a good plan and be ready to tackle XF11 before it got close. The most delightful suggestion is that we mine it to pieces, but the more likely scenario would involve nudging it into a less troublesome path. Simply blowing it up could leave a nasty schrappnel problem. With XF11, we have some time to develop skills. Another hazardous object might not give us so much notice. It's a test as to whether we as humans will succeed with our future in space. Back to Question List
We often recommend starting with binoculars and a tripod away from city lights. For about $150, you can obtain these basic optical instruments that will greatly increase your enjoyment of the night sky without a huge investment. After you've learned your way around the sky with binoculars and a starmap, if you wish to invest in a telescope, modest 6 and 8 inch aperture instruments can be obtained for under $1,000 -- new, used or built-yourself. The BEST source for telescopes in Denver USED TO BE S&S Optika, CLOSED Nov.2015 after 43 years. You can come to Chamberlin Observatory OPEN House events to meet telescope owners and learn more: twitter.com/Chamberlin_Obs for schedules and links. From time to time, DU's historic Chamberlin Observatory conducts telescope mirror making classes. Enjoy!
There are several considerations
regarding a first telescope: what use do you plan: general stargazing
(medium focal lengths) versus wide angle viewing (short focal length)
versus planetary viewing (long focal length) versus photography
(sturdy mounting and tracking)?
Don't rush into a purchase. Do
some shopping and learn about telescopes. Avoid the department and
discount stores where you'll find only inferior optical quality and
almost no advice or expertise. Do expect to pay $150 - 250 PER INCH
of aperture for good optics. Don't be misled by claims about
magnification.
Visit DU's historic Chamberlin Observatory's next
open house (303-871-5172 for schedule) and see the variety of
portable scopes displayed by astronomy club members. Also, see the
informative webpage:
http://www.skyandtelescope.com/astronomy-equipment/how-to-choose-a-telescope/
Back to
Question List
Early in the morning of Sunday Jan.11th at 00:14-00:16 AM MST, hundreds of persons witnessed a very bright meteor (bolide) streak over the Front Range of Colorado. The event was seen from north of Denver to south of Colorado Springs, coming in from the West, moving East.
Fragment recovery efforts are being coordinated by Jack Murphy, curator of geology at the Denver Museum of Natural History (303-370-6355), who has been compiling over 300 reports and trying to triangulate possible landing sites. Unfortunately, seeing the flash and even hearing a sonic boom may put a person no closer than 18 miles from the meteor, and there is no guarrantee that the rock(s) didn't vaporize fully into dust well above the ground.
HOWEVER...
"Coloradoans who were treated to a spectacular light show last weekend may have seen a piece of last year's bright comet. A review of the orbit of comet Hale-Bopp shows that it passed within 10 million miles of earth's orbital plane on May 6th. The earth passes that same ecliptic longitude early each calendar year.
The comet was moving at 30 km/sec at the time, nearly perpendicular to our orbit. Comets are known to leave extensive dust and debris in their wake, especially after a close sun pass. The separation between Hale-Bopp's orbit and the earth location on Jan.11th would require debris to come off the comet's path by 1% of the comet's speed, which is plausible. BUT SEE HOWEVER**
What may increase the odds that the meteor is part of the comet is the unusual west to east trajectory. Most objects in meteor showers radiate from east toward west, give or take a few sporadics. In fact, this week's meteor would be a "sporadic" bit of Hale-Bopp. Add to this the unusually large size of the Hale-Bopp nucleus, and its observed dramatic rotation and pinwheel of jet outflows, the likelihood of a considerable scatter of debris is even higher.
All of this makes finding the fragments of even greater interest, given that Hale-Bopp has only visited the inner solar system a few times and may be relatively pristine pre-solar materials.
HOWEVER--
In reviewing the orbital dynamics with local solar system expert, Hal
Levison, he insists that the connection is tenuous at best, because the debris
from Hale-Bopp would tend to continue moving along the comet's orbital track,
with very little radial expansion -- certainly not enough to reverse the
strong north-to-south motions to allow a fragment to enter our atmosphere
mostly from the west.
Interestingly, he noted the report during December 1997 by fishermen
along the coast of Greenland, of a huge meteoric event (flash and rush of air).
Weather and winter darkness have not permitted an inland search, but this
event could well have been a north to south moving fragment, more consistent
with Hale-Bopp origin, in principle. Thanks Hal for clarifying the above.
-----
Expert commentary:
"If the meteorite turns out to be a cometary fragment then it should also
be a classic, very primitive type of Carbonaceous Chondrite. These are
used as the standard for solar system abundances for the non-volatile
elements. As a rule this means that elements that segregated into the
Earth's core such as Iron, Nickel, cobalt, and the platinum group metals
will be much more abundant than they are in the earth's crust. The meteorite
itself should have some remnant of a fusion crust on the outside - but this
can be lost when the rock hits the ground and shatters. The inside of the
meteorite will look dark brown or black, may be very fine-grained and could
contain chondrules. Look at a picture of the Allende Meteorite as a possible
example, but note that the matrix to inclusion ratio is highly variable."
The isotopic distributions are normal for most elements, but there are
elements such as aluminum 26 and others that are made by cosmic ray
interactions that are diagnostic both of space exposure and of the time
that has elapsed since the meteorite fell to earth.
Dr. Joseph A. Nuth III
Head, Astrochemistry Branch
Code 691
NASA Goddard Space Flight Center
Greenbelt MD 20771
Phone: (301)286-9467 Fax: (301)286-1683
----
Additional reports:
"At 7:00 P.M., January 10, Pam and I were driving east on Hampden,
approaching I-25, and we saw an unusually bright meteor descending to
the east. It angled slightly from right to left. I noticed that
there were no stars visible in that direction, and I had the
impression that the meteor had pierced through a layer of clouds.
Now I wonder whether there might have been more than one fragment of
Hale-Bopp that hit the Earth?
J. Donald Hughes
John Evans Professor of History
University of Denver
Telephone 303-871-2952
----
Date: Thu, 12 Mar 1998 15:14:57 -0500
From: bird@lidar.ists.ca (John Bird)
Subject: meteor sighting at north pole
I was stationed at 81 deg. N latitude during the winter to
observe ozone and on Jan 31 0932 UT I saw an extremely bright
object (several magnitudes brighter than venus at its max brightness)
which I thought was a meteor but it was not moving.
It was captured also by a camera from the U. of Sask.
I and others saw other less bright non moving meteors
this winter. Could these be some special type of meteor
that slow down before disintegrating, possibly due to
an outer ablative layer? Perhaps we were seeing comet fragments?
Thank you for your consideration.
Dr. John Bird
URL
Office Phone : (416)665-5415, Fax : (416)665-2032
Lidar Laboratory,Center for Research in Earth and Space Technology
(CRESTech) 4850 Keele St. North York, Ontario, Canada. M3J 3K1
----
I wonder whether this would help
confirm Dr.Frank's idea of "interplanetary snowballs" pelting earth regularly,
and, just maybe, be icy bits of comets (like Hale-Bopp?) intercepting earth.
The speed of the earth in its orbit can
be estimated easily:
divide the circumference of the orbit by the
length of the year.
2 pi R / 365d * 24h
6.24 x 93 million
miles / 8760 = 67,000 mph! Back
to Question List
Hi Jessica, Thanks for your question about pulsars. Yes, the current theory for the origin of pulsars involves the leftovers of a supernova explosion - either from a collapse massive star, or a collapsed white dwarf star in a binary. Pulsars contain the mass of several suns in the space of an average town (10km) and spin rapidly. The magnetic field combined with the rapid spin and charged particles produce a beam of high energy that "flashes" past us with each rotation, rather like a lighthouse beacon. Hence the "pulse" in pulsar! Back to Question List
Hi Jennifer, Thanks for your question. My interest in astronomy started as a pre-teen, and now I run 2 observatories (DU's historic Chamberlin and Mt.Evans). No telling where you can go if you work hard.
You should take all the math and physics courses available at your school if you are serious about studying astronomy. Also, if they offer electronics and machine shop, those are valuable skills to develop early. Obviously you are familiar with computers, but do you know any programming languages, like BASIC, C++ or FORTRAN? That'd be another type of class to take, if available.
Regarding career info, if you have internet access, check this website: http://www.aas.org/career/careerbroc.html Back to Question List
Denver is blessed with 2 fine facilities: GATES PLANETARIUM at the Denver Museum of Natural History, located in City Park, at 2001 Colorado Boulevard, and the historic CHAMBERLIN OBSERVATORY of the University of Denver, located at 2930 East Warren Avenue, SE Denver. Call (303) 871-5172 for schedules.
GATES PLANETARIUM features a variety of programs for all ages, from star lore to the latest astronomical results. Call (303) 322-7009 for current schedules.
DU's historic http://mysite.du.edu/~rstencel/Chamberlin/ features an operating 20 inch aperture Clark refractor. Public nights are held on Tuesday and Thursday evenings (please call 303-871-3222 for reservations), plus the Denver Astronomical Society hosts Open House nights monthly on the Saturday near first quarter moon phase, weather permitting. The observatory also accomodates DU Astronomy Classes. Back to Question List
Light pollution refers to wasteful and excessive electric lighting that blocks our view of the night sky. Astronomers are NOT AGAINST SAFETY, but are very worried about destruction of the night sky by lighting that shines uselessly into the sky, wasting money and depriving everyone of their cosmic birthright. The simplest solution also saves money: add a shield on top of new lighting, to direct all of the light toward the ground where it is needed. Also, the use of motion sensors and timers reduce the cost of lighting to only when it is really needed. For more information, visit the International Dark Sky Association homepage at www.darksky.org. Back to Question List
"But according to the Denver
Post's daily report of sunrise and sunset, sunset has been getting
later, while sunrise has not been getting earlier. In fact, a few
days ago, the time of sunrise actually went from 7:20 AM to 7:21.
Marshall Haith has a portable computer which gives sunrise and sunset
by day and it confirms the Denver Post reports. So why doesn't the
day lengthen equally on both ends?" --Barry Hughes
Short
answer: The sun rise/set varies with your latitude and the speed of
earth in its orbit [equation of time].
An almanac will show times
of sunrise and sunset in winter vary strongly with latitude.
For
Denver, 40N, latest sunrise is late Dec/early Jan, and earliest
sunset is early Dec.
At the equator, these times shift into Feb
(latest sunrise) and Nov (earliest sunset). At the pole, the times
converge on the solstice and shortest day, Dec 20-22.
As the sun
moves thru its annual path in the sky, the angle relative to the
horizon shifts the rise and set times according to latitude, in the
manner you've discovered.
The true sun does not move thru the
sky at precisely our clock rate, due to eccentricity of the earth's
orbit. This "equation of time" produces a 'fast' sun before
winter solstice and after summer solstice, and a 'slow' sun after
winter solstice and before summer solstice. You often see this
"figure 8" on globes and is called the Analemma. It's
orientation in the sky depends on your latitude -- vertical at the
equator, horizontal at the pole. For mid latitudes like Denver, we
get our earliest sunset several days before solstice due to 'fast'
sun, and latest sunrise several days after solstice due to 'slow'
sun. Back
to Question List
While they might be legally-operating businesses, they do not have the approval of the International Astronomical Union, a federation of professional astronomers who handle the official naming of stars and planets. Although your money might buy you a nice looking certificate and promise of registry in a copyright office, astronomers are not obliged to reference these non- IAU listings. We'd recommend that you invest the same dollars in something more tangible, like an astronomy magazine subscription, book, starmap, binoculars, astronomy club membership, etc. Back to Question List
Everyone's heard of the harvest moon
that shines in autumn, but did you know the rest of the moons have
their special names as well? According to Lilian Budd (1971,
Rand-McNally, Chicago; j398.209701B585fu), these are:
SEPTEMBER -
HARVEST
OCTOBER - HUNTER
NOVEMBER - BEAVER
DECEMBER -
COLD (or Long Night or Winter Moon)
JANUARY - WOLF
FEBRUARY -
HUNGER
MARCH - WORM
APRIL - PLANTERS'
MAY - FLOWER
JUNE
- LOVERS'
JULY - MOSQUITO
AUGUST - CORN/STURGEON
Although
the months and moons don't coincide every year, this is a guide to
the traditional naming of the "moonths"! Back
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Jan. 3 -- Quadrantids
Apr.21 --
Lyrids
May 4 -- eta Aquarids
Jul.28 -- delta Aquarids
Aug.11
-- Perseids (best of summer)
Oct.21 -- Orionids
Nov.17 --
Leoinds (best of fall)
Dec.13 -- Geminids
Dec.22 -- Ursids
WHEN AND WHERE TO LOOK: Generally best seen after midnight toward
the east, as the earth 'runs into' the cometary debris stream that
causes these. The showers appear to "radiate" from their
namesake constellation, but usually the rate is fewer than ONE PER
MINUTE -- not too exciting for the Ninetendo crowd. Meteors will
flash across large parts of the sky, so no telescope or binoculars
are needed. Best seen away from city lights and when the moon is dark
or set after midnight. Back
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A popular TV program exploited public fears about a quasi-alignment of planets that happens during early May in the year 2000. The event (which actually spans weeks and is a rough alignment at best) is supposed to collapse the Antarctic ice shelf and cause the world to "fall over" -- nonsense. For one thing, the major planets Jupiter and Saturn align every 20 years or so and somehow the world goes on. Also, during this "great alignment", the giant planets Uranus and Neptune are far off the line, and even Mars is not in line. Hence, consider the alignment as pointing to good fortune for soothsayers who are eager to transfer money from your pocket to their with tales of doom on 5/5/00. Back to Question List
Denver is blessed with 2 fine facilities: GATES PLANETARIUM at the Denver Museum of Natural History, located in City Park, at 2001 Colorado Boulevard, and the historic CHAMBERLIN OBSERVATORY of the University of Denver, located at 2930 East Warren Avenue, SE Denver.
GATES PLANETARIUM features a variety of programs for all ages, from star lore to the latest astronomical results. Call (303) 322-7009 for current schedules.
DU's historic Chamberlin Observatory features an operating 20 inch aperture Clark refractor. Public nights are held on Tuesday and Thursday evenings (please call 303-871-5172 for reservations), plus the http://www.denverastro.org/ hosts Open House nights monthly on the Saturday near first quarter moon phase, weather permitting. The observatory also accomodates DU Astronomy Classes.
(c) 1996, 1997, 1998
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Return to Prof. Stencel's homepage:
http://mysite.du.edu/~rstencel.