It can be disheartening to be an astronomer living under light pollution. If your sky comes in at 7, 8, or 9 on the Bortle Scale, it’s easy to believe that there’s not much for you to see beyond the moon and planets… but that’s just not true!

Sure, the fainter deep sky objects (DSOs), such as nebulae, are likely beyond your reach (but even that’s not always true, as you’re about to see), but there are some we can see even under moderate to severe lighting.

The best deep sky objects you can see, even under severe light-polluted skies, are star clusters. These bright, dense objects, concentrated along the band of the Milky Way, can be seen in city-based telescopes without too much trouble.

Open clusters, in particular, deliver a great deal for the urban astronomer. They have different colored stars, varying densities, double stars, as well as chains and other patterns we can tease out.

M13 globular cluster, ideal for urban astronomers
M13, Hercules Cluster, is a stunning view in any telescope, even in light-polluted skies. (source)

The list below contains our pick of the best DSOs you can see as an urban stargazer. We’ve not included double stars (look for a separate post on those). Instead, we’ve chosen to look at the brightest and most interesting clusters, galaxies and, yes, even a few nebulae.

If you like a detailed guide on how to get the most from urban astronomy, click this link (opens in a new tab). Alternatively, scroll to the bottom of this page for our brief tips on improving your stargazing under light pollution.

32 DSOs for Urban Astronomers to Find

This list of objects includes their celestial coordinates, magnitude and, importantly, their surface brightness. You can read more about this vital measurement directly beneath the table.

NGC No.Other Cat. No.TypeConst.Mag.Sur. Bri.
224M31,
Andromeda Galaxy
GalAnd.3.313.5
457Owl ClusterOCCas.6.4
869/884Double ClusterOCPer.5.3
1912M38,
Starfish Cluster
OCAur.6.412.0
1960M36,
Pinwheel Cluster
OCAur.6.011.0
1976M42,
Orion Nebula
NebOri.4.011.0
2099M37OCAur.5.611.0
2632M44,
Beehive Cluster
OCCan.3.113.0
3031M81,
Bode’s Nebula
GalUma6.813.2
3034M82,
Cigar Galaxy
GalUma8.012.5
5904M5GCSer.5.711.0
6093M80GCSco.7.311.0
6205M13,
Hercules Cluster
GCHer.5.812.0
6341M92GCHer.6.411.0
6405M6,
Butterfly Cluster
OCSco.4.210.0
6475M7,
Ptolemy’s Cluster
OCSco.3.312.0
6543Caldwell 6,
Cat’s Eye Nebula
NebDra.8.15.0
6626M28GCSag.6.811.0
6633OCOph.4.6
6656M22GCSag.5.111.0
6705M11,
Wild Duck Cluster
OCScu.5.89.0
6720M57,
Ring Nebula
NebLyr.8.89.3
6779M56GCLyr.8.312.0
6826Blinking Planetary NebulaNebCyg.8.96.9
6838M71GCSta8.312.0
6853M27,
Dumbbell Nebula
NebVul.7.111.2
n/aM45,
Pleiades
OCTau.1.511.0
n/aCollinder 399,
Coathanger Asterism
OCVul.3.6
n/aCaldwell 41,
Hyades
OCTau.0.5
n/aIC 4665OCOph.4.2
n/aIC 4756OCSer.4.6
Key
For constellations, Sta = Sagitta, Uma = Ursa Major. All other constellations are the first three letters of their proper name, e.g. Cyg = Cygnus.
For Type, OC = Open Cluster, GC = Globular Cluster, Gal = Galaxy, Neb = Nebula

If you’re excited to discover more deep sky objects, including downloadable pdf guides for the complete Messier catalog, check out our sister site:
The Virtual Astronomy Club.

Why Surface Brightness is Important for Urban Astronomy

Surface brightness measures the total light output of an object (what we call its ‘magnitude’) divided across the area that object occupies in space.

For that reason, surface brightness is a much more important concept when we’re looking for objects to view in bright skies than magnitude.

As an example of why this is important, consider two Messier objects, M33, the Triangulum Galaxy, and M76, a planetary nebula known as the Little Dumbbell.

M33 has a magnitude of +5.79, which is its total brightness. M76, meanwhile, is given a magnitude of +10.10, significantly fainter, on the face of it, than M33.

However, M76 covers an area of 2.7 x 1.8 arcminutes, while M33 covers a huge 62.1 x 36.7 arcminutes, meaning its light is spread out over a much wider area.

The result of this is that the surface brightness, as measured in magnitudes per square arcsecond, of M76 is 10.4, whereas, for M33, it is 14.2.

Although M31 still has a greater surface brightness, we can see that he two objects are not nearly as different in that respect as their visual magnitude measurements would suggest.

As with many conversations about light and brightness, the details are more complex than this summary. For example, an average surface brightness hides the fact that a galaxy’s core tends to be brighter than its extremities, which is why we often only see that part of it.

If you want to dig into more details about surface brightness, check out this article from Tony Flanders. If you want to discover the surface brightness of your favorite objects, then this database is really helpful.

For now though, it’s good enough to think of surface brightness as at least as important to the urban astronomer as visual magnitude is.

How to Stargaze Under Light-Polluted Skies

There is no debate that astronomy is tougher under street lights than a dark sky, but that’s no excuse for sacrificing your hobby! Most of us live in urban areas, so there are more and more astronomers affected by light pollution.

Thankfully, there are ways to mitigate the effects of this sky-brightening menace. The following tips will help you get more from your backyard telescope when you have to do it in the city.

Go Moonless and Cloudless

Your sky is already bright, so don’t make it worse by stargazing under a full moon. Give yourself every advantage by only hunting for DSOs on moonless nights.

The same goes of clouds. Of course, stargazing is impossible under full cloud cover, but if there are just a few clouds and plenty of gaps, the dark sky astronomer can carry on. In a light-polluted area, those clouds reflect light back to Earth and brighten the sky.

If you can, elect to do your city astronomy when there are no clouds.

Reduce the Light by Stargazing Late (or Very Early)

Most towns and cities have fewer lights on the later the night gets. By the early hours of the morning, most of us have gone to bed and so house lights from your neighbors are likely to be less of an issue.

Darkness Comes After Rain

Rain drops mop up dust and other ‘aerosols’ from the atmosphere. These little suckers are responsible (in part) for bouncing that light pollution around. So you’ll find the sky is darker after rainfall.

Block Direct Sources of Light Pollution

Direct pollution comes from sources like next-door’s security lights and the street lamp on the sidewalk by your backyard.

You’ll be surprised what a difference it can make to your quality of viewing if you block these direct sources from your eyes’ and telescope’s line of sight.

Look Straight Up!

The atmosphere is thicker nearer the horizon; we have more air mass to look through. Which means… there is less pollution obstructing the view if you look straight up. Try and see objects when they’re as high as they get, ideally when they’re near the zenith.

Equipment Improvements

There are equipment changes we urban astronomers can also make to improve the view, but these require more of an investment.

A bigger telescope will always show more detail that a smaller scope but isn’t a panacea for cutting through the glare. What can make the difference is a motorized scope or a Starsense model that makes it easier to point your scope directly at faint objects. Check out this year’s best telescope models.

A cheaper option is to make your current telescope work harder by using pollution filters to block out some of that extra light. These aim to let only the good light (from DSOs, for example) reach your eye.

Even simpler and cheaper, just add a long dew cap to the end of your telescope to block out more of that direct light pollution we mentioned earlier.

Summary

Light pollution should not stop you enjoying deep sky astronomy.

There are plenty of objects out there that can be tracked down and enjoyed, especially among the many open clusters our sky contains.

With some minor adjustments to the way you do astronomy, and knowledge of the benefits of surface brightness measurements, there is no reason you shouldn’t enjoy dozens of deep sky objects from your urban backyard.

Further Reading

We’ve written a complete guide to light pollution, as well as many more details for doing astronomy in a city, which you can read by clicking the relevant links.

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