Observer: Yann POTHIER (France)
Your skill: advanced (many years) Category: planetary nebula Constellation: UMa Object data: Vmag=9.9; Bmag=12.0; 203"x199" (209" in IDB); type IIIa; central star of Vmag=16.1; discovered by Mechain in 1781; ELCAT: [OIII,496+501nm] = 12 x [Hbeta, 486nm]. RA/DE: 11h14.80m, +55°01.0' (2000.0) Date and UT of observation: 15 August 1996, 22h45UT Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36) Site classification: rural, alt.1650m (5500ft) Limiting magnitude (visual in UMi): 6.2 Transparency (1 to 5 - best to worst): 1 Seeing (1 to 5 - best to worst): 3.5 Moon up (phase?): no Instrument: Coulter 445mm/17.5" F/4.5 Magnification: 145-312x Filters used: OIII, UHC, Hbeta
Description: at 222x, large PN, round, bord quite sharp with UHC or OIII but diffuse without filter or with Hbeta; medium brightness, estimated on drawing to be 3.4' in diameter (205"); its center looks darker thanks to the two owl's eyes, oriented WNW and ESE from the very faint central star ob about mag15 (visible only at 312x without filter with great attention); the "eyes" have a diameter of about 50"; a mag 12 star is 1' from the N border; both UHC and OIII provides a very good contrast gain but Hbeta is of no use, strongly reducing the nebula's size.
