(IAAC) Sh2-90 - 17.5" F/4.5

Observer: Yann POTHIER (France)
Your skill: advanced (many years)
Object: Sh2-90 (LBN 144, GN 19.47.2)
Category: nebula
Constellation: VUL
Object data: phot.bright.=2/5; 8'x3'; emission type nebula.
RA/DE: 19h49.3m, +2652' (2000.0)
Date and UT of observation: 01 August 2003, 23h50 UT
Location & latitude: La Clapiere Obs. (France, latN44 40 00, longE06 27 36)
Site classification: rural, alt.1650m (5500ft)
Limiting magnitude (visual in UMi): 6.34 (50% of the observing time
with averted vision)
Transparency (1 to 5 - best to worst): 1
Seeing (1 to 5 - best to worst): 2
Altitude of object above horizon: 67
Moon up (phase?): no
Instrument: Coulter 445mm/17.5" F/4.5
Magnification: 74x, 125x
Filters used: UHC, OIII, Hbeta
Description: at 74x with OIII filter, and 125x with UHC filter,
medium sized nebula, extremely faint (seen less than 25% of the
observing time), suspected of beeing crescent-shaped, about 2'x1'
along a N-S axis with concavity facing E; two 14th mag. stars are
near each end of the main axis outside the nebulosity; homogeneous
nebula with ill-defined edges; UHC provides a slight contrast gain,
OIII a good one, Hbeta is of no use (so it seems to be an emission
nebula); invisible without filter.
I can provide a scanned drawing of Sh2-90 to anyone who can read the
binhex encoding of Eudora (for Mac); just mail me to try
(yann.pothier@fnac.net), it works quite often with other
Carpe noctem, Yann.
Yann Pothier
11 impasse Canart, 75012 PARIS, FRANCE
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