I am still a little behind in getting notes in order, so here are a few from late last month with some interesting targets.
Observing Report 25/4/11
All observations made using Dobsonion mounted 305mm Newtonian reflector at f/5. Eyepieces use are 34mm Meade 4000(44x) 24mm Panoptic (67x) 13mm Nagler T6 (115x) or 13mm Nagler with Barlow (230x)
Charts - Uranometria 2000 (2nd ed.) Data derived from Uranometria (2nd ed) Deep Sky Field Guide (DSFG) with additional data from The Night Sky Observers Guide (NSOG) .
Observations for 25/4/11 Transparency poor (smoke) seeing fair.
NGC 5266 Galaxy in Centaurus
RA 13 43 01.7 Dec -48 10 10 Mag(V) 11.1 Dim’ 3.2 x 2.1 SB 13.0 Type SA0- Early non-barred lenticular
From M Centauri a group of 3 stars lies 1deg to N. A mag 7 star lies 1.5deg slightly p of N with 2 stars mag 7.5 20’ apart 1deg to p. These run Nf to Sp. Point at target 20’ to Nf. Faint glow, fairly small. Averted vision needed as mag is 11.1.
NGC 5307 PN in Centaurus
RA 13 51 03.4 Dec -51 12 24 Diam” 18 Mag(P) 12.1 Mag(V) 11.2 Mag cent star 14.6
From, M Centauri a pair of faint stars (mag 7.5 and 8) lie 1deg to f about 10’ apart. A mag 7.5 star lies 15’ to N. These point to target 10-15’ to p. Small PN but easily identified at 115x and OIII filter helps. 200x reveal little structure, appears slightly elongated on one axis.
NGC 4666 Galaxy in Virgo
RA 12 45 07.6 Dec -00 27 57 Mag(V) 10.7 Dim’ 4.6 x 1.3 SB 12.5 Type SABc II-III Mixed intermediate spiral
Locate Gamma Virginis (Porrima) by naked eye. A mag 6 star lies just to f and a pair o mag 8 stars lie about 1deg to Nf about 15’ apart aligned roughly NS. Target is 30’ to Np. A group of 3 star is just to f with a faint star on p side. Very elongated at 67x, 115x makes it appear thicker with a brighter core. Some mottling is apparent.
NGC 4691 Galaxy in Virgo
RA 12 48 13.9 Dec -00 20 00 Mag(V) 11.1 Dim’ 2.8 x 2.3 SB 13.0 Type (R)SB(s)0/a pec Barred spiral with outer ring, s shaped lenticular/spiral transition with minor peculiarities.
Two mag 7 stars form a roughly NS line with f star near Porrima. Line is 3deg long. Half way between middle star and 38 Virginis lies target. Some elongation and a clear core.
NGC 5824 Globular Cluster in Lupus
RA 15 03 58.5 Dec -33 04 04 Total Vm 9.1 Brightest Star Vm 15.5 HB Vm 18.5 Diam’ 7.4 Conc class 1
Locate wide double c1 and c2 Lupi a trio of mag 6 stars lies about 3deg to Nf. Just to f side of N star is a pair of mag 7 stars which point to another mag 6 star just over 1deg away. Target is about 20’ to S of this, Small compact globular, not resolved at 115x. Stellar like core with even halo.
Post observation notes. Some interesting history on this object. “This globular cluster was discovered by James Dunlop in 1826 and cataloged by him as Dun 611. Due to some unknown reason, it was not found, observed or cataloged by John Herschel and thus missed that astronomer's General Catalogue: Dunlop's discovery remained unidentified and unacknowledged until Glen Cozens of Australia could verify it in the 1990s. Consequently, E.E. Barnard found it independently in 1884, in time to get it included in J.L.E. Dreyer's NGC.” (reproduced from http://spider.seds.org/spider/MWGC/n5824.html )
Image here http://spider.seds.org/ngc/ngcdss.cgi?obj=NGC!5824&r=15:04.0&d =-33:04&e=J2000&h=15&w=15&f=GIF&c=non e shows a highly concentrated GC. Brightest star is only 15.5 so resolving would be a major challenge, although Hartung notes a slight sparkle with 30cms.
NGC 5927 Globular Cluster in Lupus
RA 15 28 00.5 Dec -50 40 22 Total Vm 8.0 Brightest Star Vm 14.5 HB Vm 16.6 Diam’ 6.0 Conc class 8
From Zeta Lupi a group of 3 stars mag 6 to 6.5 lie 2deg to f forming a right angle triangle. The 2 f stars point to Nf at target 40’ away. Large diffuse globular with low surface brightness and no clear core. Not resolved at either 67x or 115x. Appear to be irregular in shape. Reminiscent of a large PN.
NGC 5946 Globular Cluster in Norma
RA 15 35 28.5 Dec -50 39 34 Total Vm 8.4 Brightest Star Vm not knowm HB Vm 17.2 Diam’ 3.0 Conc class 8
Just f of NGC 5927 is an isosceles triangle of mag 8 stars pointing to p visible in finder. 30’ to f of Nf star is target. Small, diffuse with low surface brightness and irregular shape. Not resolved at 115x, a small fiant twin of NGC 5927.
NGC 4463 Open Cluster in Musca
RA 12 29 56.0 Dec -64 47 24 Mag 7.2 Diam’ 6 No. of Stars 30 Mag Brightest Star 8.3 Type cl
Lies 2deg to S of Alpha Crucis (Acrux) Pretty cluster, 3 bright stars in crooked line, 12 or so other stars seen. Responds well to averted vision suggesting more fainter stars. Looks nice at 115x.
Hi Malcolm,
Another excellent report. It's good to see visual observers posting images and more detailed information about objects. I started doing it to illustrate the observation, and also as a check to ensure I was posting accurate observations and not misidentifying things. Well done!!
Know the feeling of getting behind with typing up the notes Malcolm. Interesting that we were both looking at NGC 5307 on the same night. Interesting notes on NGC 5824, thanks for those details. Nice GCs those 2 in Lupus.
Paul.
