Galaxies

An Urban Supernova

Washed-out Astronomer — Sun, 19 Jun 2011 12:05:50 +0000

A new supernova, SN 2011dh, has appeared in M51 that is at this time (June 2011) visible from typical urban and suburban skies using moderately sized telescopes. This is a unique opportunity to see a star from another galaxy without having to travel to a dark-sky site. It is rare for an extragalactic supernova to appear as bright as this, and even rarer for it to appear in a relatively well known and easily located galaxy such as M51. And not only that, but it is well position for observing in the early evenings, making it an easy target in later June when the moon is well past full. Even with a nearly full moon, I've found SN 2011dh easy to see with my 10 inch Dob. I've generated some finder charts to make it easy for anyone to locate this supernova....

Urban Messier Challenge

Washed-out Astronomer — Wed, 01 Dec 2010 02:40:42 +0000

The Messier catalog lists some of the finest objects in the northern skies. Observing all of the Messier objects is one of the classic rites of passage for amateur astronomers. There are also a variety of challenges related to the Messier Catalog, the most famous of these being the Messier Marathon: a race to see all of the Messier objects in a single night. There are also binocular Messier challenges and photographic Messier challenges. My own addition to this is an Urban Messier Challenge: a list of Messier objects that are particularly challenging for urban and suburban observers dealing with skies washed-out by light pollution. In dark skies you can see all of the Messier objects with a 3 inch (75mm) aperture, but with heavily light-polluted skies you’ll have a hard time seeing the Messier objects on my urban challenge list even with significantly larger apertures. Here is the challenge list...

Elusive Galaxies

Washed-out Astronomer — Sat, 05 Jun 2010 16:14:37 +0000

In a previous story I covered some galaxies that you can see reliably even under washed-out skies. Unfortunately some relatively bright galaxies that amateurs everywhere know and love are particularly susceptible to the effects of even modest light pollution. If you live in urban or suburban areas, you can spend hours looking for these without success. To save you this frustration, I’ve prepared a list of famous galaxies that are very hard to see in washed-out skies. You can treat this as a list of galaxies to avoid, or if you prefer, consider it a challenge list for observing under washed-out skies....
(Photo of M33 by Filip Lolić.)

Urban Galaxies

Washed-out Astronomer — Sat, 22 May 2010 23:33:09 +0000

For urban astronomers, galaxies are consistently disappointing. Galaxies that are stunning from a dark-site can be stubbornly invisible in even mildly washed-out skies. A very slight loss of contrast is enough to hide spiral arms, dark lanes and any other structural details. What makes galaxies even more frustrating is that none of the usual tricks for enhancing contrast work on them. Because they are extended objects with low surface brightness, increasing magnification just makes their already faint and diffuse light even more diffuse and fainter. Because galaxies radiate primarily stellar light, narrowband filters which can be very effective on emission and planetary nebulae don’t help at all with galaxies. So what’s an urban astronomer to do? Just give up on galaxies? Well, luckily there are a few galaxies that can be reliably seen under washed-out skies...

(Photo of M31 by Richard Arendt.)