Urban Observing List: 100 Objects for City Skies

Observe all 100 from a sky where the Milky Way is invisible

• Observe 100 objects on the list from light-polluted skies, which the League defines as a sky where you cannot see the Milky Way with the naked eye.
• The list has 87 deep-sky objects, 12 double stars and one variable star, Algol, so the 100 means the whole list.
• Log each observation as for the other League programs, with the date and time, instrument, magnification, and seeing and transparency. Observations made for the Urban program can also be used for other League programs.
• Send the logs to the Urban coordinator, or have an officer of your astronomy club review them and tell the coordinator.

The full Urban list, in the League's order, with a page for each object

Sort any column, or type a name or constellation. The type buttons above the map also filter this table. Best is the month the object is highest at 9 pm. Also on lists the other observing lists the object belongs to, so one observation can count toward more than one program where the League allows it.

37 of the 100 are best in winter: plan the list by month

Each bar counts the objects highest in the sky at 9 pm in that month. An object is also well placed in the month before, late in the evening, and the month after, early in the evening.

87 of the 100 are on another list you may already be working

• Messier: 41 of the 100
• Binocular Messier: 41 of the 100
• Deep Sky Binocular: 39 of the 100
• Herschel 400: 34 of the 100
• Open Cluster: 21 of the 100
• Caldwell: 14 of the 100
• Globular Cluster: 12 of the 100
• Planetary Nebula: 9 of the 100
• Southern Sky Telescopic: 9 of the 100
• Bright Nebula: 4 of the 100

Objects that cut through city skyglow

Phil Harrington of the Westport Astronomical Society suggested the program to bring amateur astronomy back to the cities. Its objects are bright or compact enough to show through skyglow: open clusters, globular clusters, small bright planetary nebulae, and doubles and variables, which light pollution hardly affects.

41 of the deep-sky objects are Messier objects. The rest are mostly bright open clusters such as the Double Cluster and planetary nebulae such as the Ghost of Jupiter.

More Astronomical League observing programs on Go Astronomy

• Herschel II: 400 more of William Herschel's objects, after the Herschel 400
• Binocular Messier: any 50 Messier objects with binoculars
• Bright Nebula: emission, reflection and supernova-remnant nebulae of both hemispheres
• Globular Cluster: any 50 of 190 globular clusters, with their concentration class
• Open Cluster: 100 or 125 open clusters, sketched and classified
• Planetary Nebula: 110 planetary nebulae, from the Ring to 16th-magnitude Abell shells
• Deep Sky Binocular: 60 non-Messier objects for binoculars, the step after the Binocular Messier
• Southern Skies Binocular: any 50 of 73 southern objects with binoculars
• Southern Sky Telescopic: 50 of 100 southern objects, most south of -48°
• Messier objects: the Messier Observing Program, the League's first, since 1967
• Caldwell objects: the Caldwell Observing Program
• Herschel 400: the step before Herschel II