Paddy
30-01-2010, 10:20 PM
Dear all,
Here are some notes from my session on 14th Jan., inspired to follow up on some of the observations reported by Sab and Malcolm.
Seeing was moderately good and transparency excellent. Thanks for reading.
Telescope 400mm f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Guiding: Night Sky Observer’s Guide (NSOG),
Messier 79 GC in Lepus 175x. A very interesting GC. There is quite a distinct core which appears slightly elongated N-S. Some faint resolvable stars in front of the haze of the central core. Around this central core is a gap in resolvable stars. Further out from the core is a ring of 8-10 resolvable stars. Apart from an area of haze and stars projecting from the GC to the S, the GC is about 7’ wide, the ring of resolvable stars is about 3’ in dia. The core seems to be about 2’x1’. Another ring of stars is apparent around the GC itself – 9-10 of these are very easily resolved, but there is a spattering of fainter stars in this outer ring. The strand of stars and haze branches off from the western side of the GC and heads south seems nearly as wide as the GC itself, perhaps 5-7’ long. I wonder if this is part of the GC pulled out during a turn through the plane of the galaxy, or if it is a foreground phenomenon.
IC 418 Pne in Lepus. 175x. A beautiful object, with quite bright bluish central star illuminating the purplish disc of the nebula. Dia <30”. Much brighter with averted vision. I have an impression of some darker patches in the dsic when viewed directly. These disappear with averted vision as the nebula brightens. 250X enhances brightness and sense of colour. I also have an impression of a narrow dark channel between the star and the disc of the PNe. OIII filter shows fainter ring of haze around the outside of the nebula. UHC filter also shows the nebula to have softer edges than apparent without a filter.
NGC 1888/9 GX in Lepus. 175x A nice pair of faint galaxies. 1888 is the larger of the 2 and is listed as visual mag 11, 1889 is listed at 13, but as it is smaller, it seems to have greater surface brightness. 1888 is an edge-on spiral oriented roughly N-S and 1889 is a small smudge appearing to be heading into the spiral from the east. Although they are very close, a dark space between them is visible. I have the impression of a distinct nucleus in 1889, but not in 1888 although it is brighter in the centre. 250x improves the view. I estimate that 1888 is about 5’x’1, 1889 <1’ dia.
NGC 1535 Pne in Eridanus 250x Bright blue disc with soft edge with quite bright central star. I have the impression of an inner and outer shell. The outer shell is about 1’ across, the inner shell is about half the radius and a bit brighter. UHC filter shows the firm edged inner shell and somewhat softer outer shell. I also have the impression of a flattened inverted s-shaped brightness running through the centre of the nebula, but I’m not really sure of this. OIII filter enhances the appearance of the two shells and the inner sphere looks somewhat lumpy, with quite small lobes.
NGC 3132 PNe in Vela 250x The Eight Burst Nebula. I really like this one. A bright central star, the nebula is elongated roughly SE-NW. A distinct bluish hue. A dark annulus surrounds the central star with a brighter ring around the annulus. The darker annulus is more prominent to the N of the central star. UHC filter shows the annulus as a little wider than without. OIII filter makes the darker inner ring even more distinct. The SE edge of the bright outer ring is more distinct than the NW and it gives the impression of a jellyfish heading to the SE.
NGC 2792 PNe in Vela 250x. Much smaller Pne. Smooth round haze, no central star or impression of structure. OIII filter – the nebula seems to have a grainy brightness on the southern side.
At this point, I am closely circled by a small bat. I love the way they do that – perhaps after any mosquitoes that I may attract.
NGC 2438
At this PNe in Puppis. 250x A lovely bit of sky with crowding of stars of the OC M46 around the PNe. It appears to have a bright central star, but NSOG informs me that this star is part of M46 and that the PNe’s star is too faint at mag 17. There is quite a wide dark annulus around the visible star and a bright ring around that. UHC filter confirms the sense of the dark annulus unless. OIII filter gives the impression of notchiness at the junction of the dark annulus with the outer ring.
Mars 175x North polar cap is quite distinct. There is a small dark wedge immediately to the south of the polar cap. A larger, fainter area of patchy darkness extends from just to the south of the cap about a third of the way across the disc. I note a paler orange area on the western limb of the disc just below the dark line to the south of the polar ice cap. This is the most detail that I’ve ever seen on Mars – it actually looks like it does in the pictures!
Here are some notes from my session on 14th Jan., inspired to follow up on some of the observations reported by Sab and Malcolm.
Seeing was moderately good and transparency excellent. Thanks for reading.
Telescope 400mm f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Guiding: Night Sky Observer’s Guide (NSOG),
Messier 79 GC in Lepus 175x. A very interesting GC. There is quite a distinct core which appears slightly elongated N-S. Some faint resolvable stars in front of the haze of the central core. Around this central core is a gap in resolvable stars. Further out from the core is a ring of 8-10 resolvable stars. Apart from an area of haze and stars projecting from the GC to the S, the GC is about 7’ wide, the ring of resolvable stars is about 3’ in dia. The core seems to be about 2’x1’. Another ring of stars is apparent around the GC itself – 9-10 of these are very easily resolved, but there is a spattering of fainter stars in this outer ring. The strand of stars and haze branches off from the western side of the GC and heads south seems nearly as wide as the GC itself, perhaps 5-7’ long. I wonder if this is part of the GC pulled out during a turn through the plane of the galaxy, or if it is a foreground phenomenon.
IC 418 Pne in Lepus. 175x. A beautiful object, with quite bright bluish central star illuminating the purplish disc of the nebula. Dia <30”. Much brighter with averted vision. I have an impression of some darker patches in the dsic when viewed directly. These disappear with averted vision as the nebula brightens. 250X enhances brightness and sense of colour. I also have an impression of a narrow dark channel between the star and the disc of the PNe. OIII filter shows fainter ring of haze around the outside of the nebula. UHC filter also shows the nebula to have softer edges than apparent without a filter.
NGC 1888/9 GX in Lepus. 175x A nice pair of faint galaxies. 1888 is the larger of the 2 and is listed as visual mag 11, 1889 is listed at 13, but as it is smaller, it seems to have greater surface brightness. 1888 is an edge-on spiral oriented roughly N-S and 1889 is a small smudge appearing to be heading into the spiral from the east. Although they are very close, a dark space between them is visible. I have the impression of a distinct nucleus in 1889, but not in 1888 although it is brighter in the centre. 250x improves the view. I estimate that 1888 is about 5’x’1, 1889 <1’ dia.
NGC 1535 Pne in Eridanus 250x Bright blue disc with soft edge with quite bright central star. I have the impression of an inner and outer shell. The outer shell is about 1’ across, the inner shell is about half the radius and a bit brighter. UHC filter shows the firm edged inner shell and somewhat softer outer shell. I also have the impression of a flattened inverted s-shaped brightness running through the centre of the nebula, but I’m not really sure of this. OIII filter enhances the appearance of the two shells and the inner sphere looks somewhat lumpy, with quite small lobes.
NGC 3132 PNe in Vela 250x The Eight Burst Nebula. I really like this one. A bright central star, the nebula is elongated roughly SE-NW. A distinct bluish hue. A dark annulus surrounds the central star with a brighter ring around the annulus. The darker annulus is more prominent to the N of the central star. UHC filter shows the annulus as a little wider than without. OIII filter makes the darker inner ring even more distinct. The SE edge of the bright outer ring is more distinct than the NW and it gives the impression of a jellyfish heading to the SE.
NGC 2792 PNe in Vela 250x. Much smaller Pne. Smooth round haze, no central star or impression of structure. OIII filter – the nebula seems to have a grainy brightness on the southern side.
At this point, I am closely circled by a small bat. I love the way they do that – perhaps after any mosquitoes that I may attract.
NGC 2438
At this PNe in Puppis. 250x A lovely bit of sky with crowding of stars of the OC M46 around the PNe. It appears to have a bright central star, but NSOG informs me that this star is part of M46 and that the PNe’s star is too faint at mag 17. There is quite a wide dark annulus around the visible star and a bright ring around that. UHC filter confirms the sense of the dark annulus unless. OIII filter gives the impression of notchiness at the junction of the dark annulus with the outer ring.
Mars 175x North polar cap is quite distinct. There is a small dark wedge immediately to the south of the polar cap. A larger, fainter area of patchy darkness extends from just to the south of the cap about a third of the way across the disc. I note a paler orange area on the western limb of the disc just below the dark line to the south of the polar ice cap. This is the most detail that I’ve ever seen on Mars – it actually looks like it does in the pictures!