Leo I Dwarf Galaxy (Regulus Dwarf) UGC 5470, CGCG 64-73, MCG+2-26-27, DDO74, PGC 29488
Leo
RA: 10 08 28
Dec: +12 18 27
Size: 9.8 x 7.4’
Mag: 11.2b
SB: 15.2
Class: E3
Urano: 93L
Leo I is a local group dwarf spheroidal galaxy located about 900k light-years distant. It is thought to be one of the most distant satellites of the Milky Way galaxy. 1950 by Albert George Wilson discovered Leo I in 1950, by peeling through the POSS-I plates taken with the 48-inch Schmidt camera at Palomar Observatory. Leo I was one of the four local group dwarf galaxies that he discovered by looking over the POSS-I plates.
To date, no globular clusters have been found to be associated to Leo I.
Leo I is located 20’ north of Regulus, thus sometimes called the Regulus Dwarf.
This object was detected visually with telescopes as small as 4”. From Cloudy Nights, Bill Ferris seen it twice with his 6” reflector. Noted that the key is not higher magnification and Regulus need to be off the field. Dan from CN saw it in a 132mm William Optics refractor. Don Pensack saw it in a 6” f/5 telescope. Sue French observed it ay 87x with her 4” refractor.
Personally, I have not looked for it in anything smaller than my old 6” f/6.5 achromat. With that telescope at 76x using the 13mm Ethos, it was a 3:2 elongated large very low surface brightness glow with very ill-defined edges. I’ve seen it many times with my 22” reflector at 96x with a 24mm Panoptic, but with no detail, just a large low SB glow with ill-defined edges. Nothing else. Once Regulus pops in the field, Leo I is not visible.
I think I would like to give this galaxy a shot with my 4” f/11 refractor.
On a side note, I've uploaded a major updated Local Group Observer's guide available for free download on my website. Leo I is on Page 55
DSS image showing its proximity to Regulus Leo I DSS.jpg
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