|Leo I: Dwarf Galaxy (Leo) RA: 10h 08.5m / DEC: +12° 18'.5|
Instrument: 10-inch Starfinder
Leo I is a difficult object for any contrast-challenged optical system. My 10-inch, f/4.5 Newtonian is a case in point. Although the 24% central obstruction does not introduce overwhelming aberrations, the loss of contrast is enough to make me wish for something a bit more optimized. Oh well, maybe my next scope.
Leo I is a Local Group galaxy residing 20' north of 1.4 magnitude Regulus in Leo. The glow from nearby Regulus threatens to wash out the sky in an obstructed or poorly baffled optical system. I had to position Leo I just a few arc minutes inside the southern edge of my field of view in order to eliminate light pollution from Regulus. The sketch at left renders this observation, which was made at 190X with the 10-inch Newtonian.
The field of view is 20' across at that magnification. Leo I appears as several irregular nebulous patches. A Y-shaped section in the western half is brightest. Leo I ranges over a 9'x6'.5 area and is aligned roughly east-to-west. A pair of 11th magnitude GSC stars, separated by 1'.5, stand immediately north of the dwarf galaxy's east edge. A second, more widely spaced pair stands north of the west end.
Layout, design & revisions © W. D. Ferris
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Revised: October 30, 2005 [WDF]