M.A.R.S. stands for the Mountain Astronomical Research Section. A regional section of the Astronomical League, its members include, but are not limited to,  the Colorado Springs Astronomical Society, the Longmont Astronomical Society, the Northern Colorado Astronomical Society, and the Denver Astronomical  Society. The CSAS, LAS, CAS, BCAC, and NCAS are our friends and neighbors within FRASC. Check in on them at their web sites.

• The MARS Web page
• Black Canyon Astronomical Club (Montrose)
• Boulder Astronomy and Space Society
• The Cheyenne Astronomical Society 
• The Colorado Springs Astronomical Society web page
• Front Range Astronomical Supercluster (FRASC)
• The Laramie Astronomical Society & Space Observers' (LASSO) homepage
• The Longmont Astronomical Society web page
• The Northern Colorado Astronomical Society
• Rocky Mountain Astronomy Club (new club in Pueblo)
• The Web site of Denver University's Dr. Robert Stencel
• Western Amateur Astronomers (WAA)
• Western Colorado Astronomy Club
• A3 (A-Cubed)

• Amateur Astronomy 
• "Astronomy" Magazine's web site
• Astronomy and Space 
• ATM Journal 
  Amateur Telescope Making Journal--Publication ended with 17-18 double issue (plans are for an online journal)
• Icarus 
• Meteorite! Magazine 
• Popular Science
• SETIQuest 
• "Sky & Telescope" Magazine
• The Astronomer Online
• The Woman Astronomer

Astrophotography & Imaging 

• Jerry Lodriguss' "Catching the Light" Site 
• Dr. Travis Rector's Astrophotos--great site shows some of the digital images Travis has made with MOSAIC, the wide-field CCD imaging cameras, on the telescopes at Kitt Peak in Arizona and Cerro Tololo in Chile.
• Astronomy Picture of the Day 
• The Cookbook CCD Camera Home Page 
• Astronomical Imaging by Brad Wallis and Robert P

• Clear Dark Sky. Provides "Clear Sky Clocks" for thousands of observing locations in the U.S. and Canada, including Denver and the DAS EGKDS.
• The Silicon Sky. This site has weather links and info for astronomers and just about everything else, including a guestbook that you can fill out. It also has comet-related pages, including a Hale-Bopp logbook that you can contribute to, based on your observations.
• National Weather Service - Interactive Weather Information Network (IWIN)
• Intellicast; another fine weather site.

• Adirondack Public Observatory: The Wild Center
• Ames Area Amateur Astronomers (IA): McFarland Park Observatory | Map
• Austin Astronomical Society: Eagle Eye Observatory
• Barnard-Seyfert Astronomical Society (TN): Spot Observatory
• Battle Point Astronomical Association (WA): Edwin Ritchie Observatory
• Bays Mountain Astronomy Club | Bays Mountain Park Observatories
• Black Hills Astronomical Society: Hidden Valley Observatory
• Bristol Astronomy Club (TN): Burke Observatory | Telescopes
• Buffalo Astronomical Society: Beaver Meadow Observatory , Remick Observatory, Lockport
• Calumet Astronomical Society (IN): Conway Observatory
• Cedar Amateur Astronomers (IA): Palisades-Dows Observatory
• Cincinnati Astronomical Society: Dark Sky Site | Observatories
• Delaware Valley Amateur Astronomers (PA): Colonial Observatory
• Denver Astronomical Society: Edmund G. Kline Dark Site
• Des Moines Astronomical Society (IA): Ashton Observatory
• Door Peninsula Astronomy Society (WI): Leif Everson Observatory
• Eastern Missouri Dark Sky Observers: The 30" Observatory
• Evansville Astronomical Society (IN): Wahnsiedler Observatory History | Photos
• Fort Bend Astronomy Club (TX): George Observatory
• Fort Wayne Astronomical Society (IN): FWAS Observatory
• Fort Worth Astronomical Society : FWAS Observing Site
• Harford County Astronomical Society (MD): Harford Community College Observatory
• Houston Astronomical Society: Columbus Observatory
• Howard Astronomical League: Observatory Project Status | Watson Scope
• Kalamazoo Astronomical Society (MI): Owl Observatory
• Kansas City, Astronomical Society of: Powell Observatory, Lewisburg, Kansas
• Las Cruces (NM), Astronomical Society of: Observatory Project at Leasburg Dam State Park
• Los Angeles Astronomical Society: Garvey Ranch Observatory & Steve Kufeld Astronomical Site
• Louisville Astronomical Society (KY): LAS Urban Astronomy Center | Curby Dark Site
• Marquette Astronomical Society (MI): MAS Observatory
• Miami Valley (OH) Astronomical Society: Apollo Observatory, John Bryan State Park Observatory, Merry Go Round Observatory
• Milwaukee Astronomical Society: MAS Observatory
• Minnesota Astronomical Society: Onan Observatory
• Mohawk Valley Astronomical Society: Apollo Observatory
• Naperville Astronomical Association (IL): Glen D. Riley Observatory
• New Jersey, United Astronomy Clubs, Inc: Jenny Jump Observatory
• Northeast Kansas Amateur Astronomer's League: Farpoint Observatory
• Northern Cross Science Foundation (WI): Jim and Gwen Plunckett Observatory
• Northern New England, Astronomical Society of (ME): Starfield Observatory | Details
• Northern Virginia Astronomy Club | Robotic Telescope
• Oil Region Astronomical Society (PA): Oil Region Observatory
• Oklahoma City Astronomy Club, Cheddar Ranch Observatory
• Orange County Astronomers (CA): OCA Observatories | Kuhn Telescope
• Ponchartrain Astronomy Society (LA): Larry Paulk Memorial Observing Site | Photos
• Popular Astronomy Club (Rock Island, IL): PAC Mobile Observatory
• Richland Astronomical Society (OH): Warren Rupp Observatory
• Richmond Astronomical Society (VA): RAS Observatory
• Rockford Amateur Astronomers (IL): Rockford Park Observatory
• San Angelo Astronomy Association (TX): SAAA Observing Sites
• Shenandoah Astronomical Society (VA): Morgan County Observatory
• Shreveport-Bossier Astronomical Society (LA): Worley Observatory
• Skylight Astronomical Society (MA): Rockbottom Observatory (privately owned)
• Springfield Telescope Makers, Inc.: Stellafane
• Syracuse Astronomical Society: Darling Hill Observatory
• Texas Astronomy Society of Dallas: Al Bowen Observatory (in membership brochure - PDF)
• Tulsa, Astronomy Club of: Mounds Observatory
• Von Braun Astronomical Society, (Huntsville, AL): Conrad Swanson Observatory and Wilhelm Angele Observatory
• Warren Astronomical Society (MI): Stargate Observatory
• Wehr Astronomical Society, Inc.: WAS Observatory
• Westminster Astronomical Society (MD):  Observatory Plans
• York County Astronomical Society (PA): YCAS Observatory & Radio Telescope

• Badlands Observatory: Black Hills Astronomical Society
• Bays Mountain Park Observatories: Bays Mountain Astronomy Club
• Burke Observatory, King College (TN): Bristol Astronomy Club
• Chabot Observatory and Space Center (CA): Eastbay Astronomical Society
• Chamberlin Observatory, University of Denver: Denver Astronomical Society
• Clarence T. Jones Observatory, University of Tennessee -- Chattanooga: Barnard Astronomical Society
• Custer Observatory: Amateur Observers Society of New York
• Cincinnati Observatory Center: Friends of the Observatory
• Dyer Observatory, Vanderbilt University: Barnard-Seyfert Astronomical Society
• George Observatory, Houston Museum of Natural Science: Fort Bend Astronomy Club (TX)
• Griffith Observatory, Los Angeles: Los Angeles Astronomical Society
• Grundy Observatory, Franklin & Marshall: Astronomy Enthusiasts of Lancaster County, PA
• Hobbs Observatory, Beaver Creek Reserve: Chippewa Creek Astronomical Society
• Hyde Memorial Observatory, Lincoln, NE: Prairie Astronomy Club, Lincoln, NE
• Laws Observatory, University of Missouri: Central Missouri Astronomical Assocation
• Morrison Observatory, Central Methodist College, Fayette, Missouri: Central Missouri Astronomical Association.
• Perkins Observatory, Ohio Wesleyan University: Columbus Astronomical Society
• Pine Mountain Observatory, University of Oregon: Friends of Pine Mountain Observatory
• St. Louis Observatory, University of Missouri: St. Louis Astronomical Society
• Sommers-Bausch Observatory, CU Boulder: Boulder Astronomy and Space Society
• University of Maryland Observatory, National Capital Astronomers

• SkyView Virtual Observatory
• SOHO; The Solar and Heliospheric Observatory
• University of Colorado's Sommers Bausch Observatory
• Space Telescope Science Institute
• The World's Largest Optical Telescopes
• Anglo-Australian Observatory (Epping, Australia)
• Big Bear Solar Observatory (Big Bear City, California)
• Cerro Tololo Inter-American Observatory (CTIO; Chile)
• European Southern Observatory (ESO; Germany & Chile)
• Gemini 8-meter Telescopes (Hawaii & Chile)
• Infrared Telescope Facility (IRTF; Hawaii)
• Large Binocular Telescope (LBT; Arizona)
• Mauna Kea Observatories (Hawaii)
• McDonald Observatory (Texas)
• Multiple Mirror Telescope (MMT; Tucson, Arizona)
• National Radio Astronomy Observatory (NRAO; AZ, NM, VA, WV)
• National Solar Observatory (NSO; Arizona, New Mexico)
• Near-Earth Asteroid Tracking (NEAT; Hawaii)
• Palomar Observatory (California)
• Roque de los Muchachos Observatory (Tenerife, Canary Islands)
• Royal Greenwich Observatory (RGO; England)
• Subaru Telescope (Hawaii)
• University of Toronto Southern Observatory (Chile)
• Yerkes Observatory (Williams Bay, Wisconsin)
• Kuiper Airborne Observatory (KAO)
• Stratospheric Observatory for Infrared Astronomy (SOFIA)

• Astronomy Ireland
• The Astronomical League 
  • The A.L.'s Sales Office
• The FRAC (Front Range Astronomy Clubs) Website
• International Dark-Sky Association
• International Association for Astronomical Studies 
  • IAAS Newsletter
• International Occultation Timing Association (IOTA)
• Western Amateur Astronomers
• The A.L.'s AstroCon 2000
• The Antique Telescope Society
• The International Occultation Timing Association, with two URLs: 
  • http://www.sky.net/~robinson 
  • http://www.anomalies.com/ 
• The American Association of Variable Star Observers
• Lake County Astronomical Society (Chicago area)
• North American Meteor Network
• International Supernova Network
• The Association of Lunar and Planetary Observers
• A.L.P.O.'s "The Digital Lens; Solar System Astronomical Computing Newsletter"
• The Astronomical Society of the Pacific
• International Association for Astronomical Studies

• Comet Observation Home Page
• GSOC Satellite Visibility Home Page
• IAU's Observable Comets Page (Ephemerides are posted continuosly)
• IAU's page to load ephemerides into your favorite software program
• The Lunar Web Site
• Ron Muir's Deep Sky Guide
• Observable Deep Sky Objects
• Online Messier Catalog
• Sky&Telescope's Online's Comet Page
• The Web Nebulae

• Universe Today
• NASA Home Page
• Canadian Space Agency (CSA)
• European Space Agency (ESA)
• National Space Development Agency of Japan
• Next Generation Space Telescope (NGST)
• Hubble Space Telescope (HST)
• Space Shuttle
• Mir
• International Space Station Alpha 

• Astrosystems
• Galaxy Optics
• Obsession Telescopes
• JMI
• Software Bisque 
• Celestron
• Meade
• Tele Vue
• Astro-Physics
• Questar
• Takahashi America
  • Land, Sea, and Sky
  • Anacortes Telescope & Wild Bird
• Losmandy
• SBIG
• Virgo Astronomics
• Steiner
• Bushnell
• Swarovski
• Pentax
• Zeiss
• Leica
• Nikon
• Canon
• Coronado Filters
• Here are two comprehensive guides to manufacturers; 
  • Astro-Links
  • Astro-Guide

• American Association of Amateur Astronomers
• Astronomical League
• Cambridge University Press
• Dover Publications
• Harvard University Press
• National Academies Press
• New Astronomy Press
• Princeton University Press
• Sky and Telescope
• Springer-Verlag
• TelosNet Astrologs
• Willman-Bell

• ATM Resources
• Astromart
• Dale Keller's ATM page
• The DAS For Sale/Wanted Page
• CloudyNights Classified

• AllExperts.com's Astronomy Page
• Denver Museum of Nature & Science
• Heavens Above will help you compute flashes for your area from iridium satellites.
• North American Skies
• Rawhide Space Page
• Space Science Planetarium (formerly known as Gates Planetarium)
• Star Hustler--Jack Horkheimer
• The Amateur Astronomy Newsgroup
• The Colorado Astronomy Page
• The Sky Guide
• The web site for the astronomical comic strip; Starman, plus many interesting links to other sites
• "Under the Western Sky..." Stars and Lore of the Great American West