Opposite from Canes Venaciti and to the celestial south of the Virgo Galaxy Cluster are a filament of galaxies called the Virgo Southern Extension. The Southern Extension of the Virgo Cluster has always been ill-defined to me in 3-D: Virgo Cluster and southern extension in 3D http://www.slas.us/gallery2/main.php?g2_itemId=3244 Color Tully galaxy group Dark Blue Local Group Red Coma - Sculptor Cloud Green - dark Leo Cloud Green - light Leo Spur Purple Triangulum Spur Teal Virgo Cluster and Southern Extension Yellow - dark Fornax Cluster and Eridanus Cloud Yellow - light Dorado Cloud Black Not coded in this view - but is easily understood in terms of a 2D plot of its members in the celestial coordinate system: Overview chart of the Virgo Supercluster galaxy groups Unlabeled http://www.slas.us/gallery2/main.php?g2_itemId=3305 Galaxy group labeled http://www.slas.us/gallery2/main.php?g2_itemId=3280 The southern extension of the Virgo Cluster is traced by four showcase galaxies: M49 NGC4472 M61 NGC4303 Caldwell52 NGC4697 M104 NGC4594 Virgo Southern Extension galaxy trace http://www.slas.us/gallery2/main.php?g2_itemId=3283 For these four showcase galaxies in the southern extension, I divide the southern extension into two parts for finding purposes - the "northern half" of the southern extension containing M49 and M61 and the "southern half" of the southern extension containing Caldwell 52 and M104. After work practice from a light polluted urban site can aid in finding locator stars for both sets of targets. To find M49 and M61, use the following finder chart: Finder for M49 and M61 - celestial north end of Virgo Southern Extension http://www.slas.us/gallery2/main.php?g2_itemId=3286 To star or finder hop to M49, I like to start at Vindemiatrix (eps Vir). Under light polluted skies using binos, I can still easily find rho Vir and the triangle asterism anchored by mag 5.2 star 32 Vir (SAO119574). From the triangle asterism, then try to find the faint diamond asterism with north south vertices consisting of 20 Virgo (SAO100146) and SAO119453. See chart. M49 lies in the 1.2 degree space between SAO119453 (v6.0) and SAO119413 (v6.4). All or part of the diamond asterism may be an averted object from a light-polluted site. For M61, the closest star hop locator star is 16 Vir (SAO119341, v5.0). 16 Vir easily can be found with a declination slew from eta Vir (16 Vir). eta Vir also easily found in very light polluted skies bewteen bet Vir and Porrima (gam Vir). eta Vir is the only optical wide double along a bet-to-gam Vir sweep line. Once computer synched to 16 Vir, computer control is the easiest means to slew to M61. M61 is about a 1 deg RA by 2 deg Dec right-angle slew from 16 Vir. The key for light-polluted sky practice with binos is to practice locating 16 Vir. M104 and Caldwell 52 are celestial south of Porrima (gam Vir). Finding them under a weekend dark sky can also benefit from weekday after work locator star hop practice. Finder for M104 and Caldwell 52 - celestial south end of Virgo Southern Extension http://www.slas.us/gallery2/main.php?g2_itemId=3308 For Caldwell 52 (NGC4697), a quick and dirty direct slew method is to due a 5.3° right-ascension slew from theta Virgo. An indirect star hop method to Caldwell 52 (and to M104) is to locate chi Vir (26 Vir) - which is visible with binos under a light-polluted sky. To get to chi Vir (26 Vir), begin at Spica (alf Vir). Walk a series of three medium bright mag 5.0 class stars ending in 26 Vir: Spica -> 49 Vir -> psi Vir (40 Vir) -> ending with chi Vir (26 Vir). Under light polluted skies, this line series of star hops easily is seen with binos. From 26 Vir, Caldwell 52 is best found by computer synching and slewing to NGC 4697. By star hopping, the trick is to find faint SAO138697 about 3 degrees at a PA of 45 degrees from 26 Vir. Caldwell 52 is within one degree of SAO138697. There are a number of routes to M104. From 26 Vir, put 26 Vir at the eastern edge of a 1.25 deg eyepiece TFOV and then do a 3.5 degree declination slew to M104. A southern entry star hop route begins at eta Corvus. Under light polluted skies with binos, a triangular asterism anchored by v5.7 star SAO157350 easily can be found. The celestial northern edge this asterism points to M104 - about 2 degrees away. An intermediate hop from the SAO157350 triangle asterism is Harrington 20 - "The Stargate". This is a group of two optical triangle asterism nestled within one another. The Stargate's brigthest star is v6.7 star SAO15739 - which may or may not be in your handcontroller's database. M104 is a 1 deg by 1 deg right-angle slew from the Stargate. Practicing these star hops for bright locator stars during the week can aid in finding related DSOs from a weekend dark sky site. Clear Skies - Kurt Stargate and Jaws asterims near M104 - photo http://www.astro-pat.com/Latest/M104-Jaws-Stargate-032409.htm