NGC 3918 is a bright planetary nebula in the constellation Centaurus, nicknamed the "
Blue Planetary" or "
The Southerner". It is the brightestof the far southern planetary nebulae. This nebula was discovered by Sir John Herschel in March 1834 and is easily visible through small telescopes. The round or even slightly oval diameter is telescopically between 8 and 10 arcsec, though deep images extends this to about 19 or 20 arcsec. More surprising is the beautiful rich blue colour that looks much like the coloured images of Neptunetaken by Voyager 2 in 1989.
Spectroscopy reveals NGC 3918 is approaching us at 17±3.0 kilometres per second, while the nebulosity is expanding at around 24 kilometres per second. The central star is 14.6 visible light magnitude, and remains invisible to optical observers, as it is obscured by the sheer brightness of the surrounding nebula.
[2]
The distance is estimated at 1.5 kpc (4 900 light-years).
Equipment:
GSO 10" f/8 Truss RC Losmandy G11 Mount guided PHD2 Orion Starshoot on 60mm guide scope
I need a bigger scope for this target or maybe the subs should have been a shorter exposure time
https://static.xx.fbcdn.net/images/e...1/16/1f642.png
QHY 268c one shot colour camera, -15c, . Gain 57 Offset 30 Ezcap QT capture software, with Optonlong L Extreme filter
Time/Locale:
3hrs 6min in 93frames frames exposure in 2 min long subs captured 04/03/2023 Bortle 5 sky between 8:17pm and 11:53,
Najm Nazm Observatory Kelmscott WA, waxing gibbious moon 92%
Processing: Stacked DSS, then P2, PS6
Note: the small image bottom right was taken by another with a 320mm f/9 RC so this gives you some idea of the scale
