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Old 12-02-2011, 05:39 PM
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Observation Report 28/1/11 to 8/2/11 Part 2

Observations 30/01/11

NGC 1807 and 1817 Open Clusters in Taurus
NGC 1807 RA 05 10 46.0 Dec +16 31 00 Mag 7.0 Diam’ 12 No of Stars 37 Brightest Star Mag 9.0 Type cl
NGC 1817 RA 05 12 27.0 Dec +16 41 00 Mag 7.7 Diam’ 20 No of Stars 283 Brightest Star Mag 9.0 Type cl

Locate Pi Orionis (N star of Orion’s shield) move about 3 or 4deg to N to a wide trapezium of bright stars. 3 stars lie in a wide obtuse triangle 3deg just N of f. Both target lie just to N of f star. NGC 1817 is f member of pair. NGC 1817 contains 5 brighter stars located on p side of group which form a tiny asterism reminiscent of the main stars in Delphinus. The f side is a large array of fainter stars, at 115x around 2 or 3 dozen stars are resolved but hundreds more are suggested.
NGC 1807 lies 10’ to p. Has a NS line of 4/5 bright stars, maybe another 4 or 5 stars are resolved. Noticably smaller than NGC 1817, both fit in FOV at 67x.

NGC 2423 Open Cluster in Canis Major
RA 07 35 07.0 Dec -13 52 00 Mag 6.7 Diam’ 12 No of Stars 86 Brightest Star Mag 9.0 Type cl

Sits 30’ to N of M47 (naked eye cluster). Fairly large, fills 50% of field at 67x. Rich in bright stars, appears to have a “bridge” of stars running towards M47.

NGC 2818 Planetary Nebula and Open Cluster in Pyxis
PN RA 09 16 01.5 Dec -36 37 37 Diam” 93 Mag(P) 13.0 Mag(V) 11.6 Mag Cent Star 19.5
OC RA 09 16 10.0 Dec -36 37 00 Mag 8.2 Diam’ 8 No of Stars 298 Brightest Star Mag 11.3 Type clpn

Locate Psi Velorum. A line of bright stars lies about 4deg to Nf which is about 2deg wide. S star of this line is k Velorum. Target lies 50’ to N of this star. Largish cluster of many faint stars. The Plantary Neb is very clear at 115x. PN is round a fairly diffuse with no central star visible. OIII shows very clearly. Very strong resemblance to M46 is noted.

Post observation notes. Not surprisingly searches of the internet do show some confusion as to the nature of this object. The AAO image here http://www.aao.gov.au/images/captions/aat080.html states it is both an OC and PN but the DSS image here at the NGC/IC project indicates it is only the PN. Object originally discovered by Dunlop as number 564.

Observations 02/02/11

NGC 2158 Open Cluster in Gemini
RA 06 07 26.0 Dec +24 05 48 Mag 8.6 Diam’ 5 No of Stars 973 Brightest Star Mag 15.0 Type cl

Locate Propus (Eta Geminorum) and 1 Geminorum by naked eye. Move 1.5deg to Nf from 1 Gem to find glow of M35 in finder. Move back 20’ towards I gem. Very faint glow is detected in eyepiece at 67x. Just resolved 3 or 4 stars at 115x.

NGC 2129 Open Cluster in Gemini
RA 06 01 06.0 Dec +23 19 24 Mag 6.7 Diam’ 6 No of Stars 73 Brightest Star Mag 10.0 Type cl

Lies 50’ to p of 1 Geminorum. Small with 3 bright stars that may be foreground objects. No obvious central concentration.

Observations 06/02/11

NGC 2232 Open Cluster in Monoceros
RA 06 28 02.0 Dec -04 51 00 Mag 4.2 Diam’ 45 No of Stars 20 Brightest Star Mag 5.0 Type cl

Fairly large and sparse, maybe 15 to 20 stars visible. Brightest star estimated at mag 5. Seems to form a shape of an acute triangle running NS.

NGC 2219 Open Cluster in Monoceros
RA 06 23 42.0 Dec -04 41 00 Mag Not given Diam’ 10 No of Stars 25 Brightest Star Mag 7.3 Type cl

Lies 1 deg to p of NGC 2232. Has a pair of stars (maybe foreground?) mag 6.5 and 7 on p and f edges (p star is the brighter). Remainder of stars very faint and not easily seen.

NGC 2184 Open Cluster in Orion
RA 06 11 41.0 Dec -03 36 00 Mag Not given Diam’ 33 No of Stars 30 Brightest Star Mag 9.0 Type cl?

Consists of 25 to 30 stars of about mag 9 in a 30’ wide field. A mag 5.5 star lies on p side. Wide and sparse but a very pretty Open Cluster

Observations 08/02/11

NGC 2301 Open Cluster in Monoceros
RA 06 51 46.0 Dec +00 28 00 Mag 6.0 Diam’ 15 No of Stars 80 Brightest Star Mag 8.0 Type cl

Locate Delta Monocerotis. A distinct “house” shaped asterism lies 5deg to p and slightly S of this. Target is visible as an elongated patch in finder about 1deg N of this group.
Has a number of bright stars arranged in a “cascade” running NS. Chart indicates this lies on Sp side of cluster. Many other bright stars fill field at 67x Very nice Open Cluster.

Post observation notes. O’Meara lists this cluster at number 39 in his list of Hidden Treasures. DSS image here http://spider.seds.org/ngc/ngcdss.cgi?obj=NGC!2301&r=6:51.8&d= +00:28&e=J2000&h=15&w=15&f=GIF&c=no ne certainly doesn’t do it justice as it is a very satisfying object in the eyepiece.

NGC 2353 Open Cluster in Monoceros
RA 07 14 31.0 Dec -10 16 00 Mag 7.1 Diam’ 18 No of Stars 106 Brightest Star Mag 9.0 Type cl

Sits around middle star of a line of 3 mag 6 stars about 4deg to Sf of M50. Has about 30 moderate brightness stars in a wide group. Seems to be arranged in 2 groups when examined closely. South group is quite round and N group it elongated.

NGC 2440 Planetary Nebula in Puppis
RA 09 27 03.5 Dec -56 06 18 Diam” 117 Mag(P) 12.2 Mag(V) 11.8 Mag Cent Star 15.9

Very small but quite bright Planetary Nebula. Slightly elongated with a faint green tinge. OIII filter shows very well.

Post observation notes. Nice image of NGC 2440 is here http://www.noao.edu/outreach/aop/observers/n2440.html O’Meara lists this cluster at number 41 in his list of Hidden Treasures. He indicates that at high power the central star can be observed in a 10” scope but I saw no evidence. It would be an interesting object to see as the surface temperature of the star is estimated at 200,000degrees C, making it one of the hottest stars ever measured. NGC 2440 is also an example of a Planetary Neb with multiple lobes, with observers seeing 3 lobes rather than the more common 2.

Malcolm
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Old 13-02-2011, 07:34 PM
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Paddy (Patrick)
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Great reports there Malcolm and some very nice observations and quite a range of targets. 2818 I reckon is particularly interesting cluster and PN. Good suggestion to include it in the Feb Challenge.
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Old 13-02-2011, 09:11 PM
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barx1963 (Malcolm)
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Thanks Paddy. It's been really nice to actually get some time at the eyepiece in the last couple of weeks. I'm starting to work up a list of objects for Snake Valley, a few from this report will be on it.
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Old 17-02-2011, 05:18 PM
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Great set of observations Malcolm. I'm interested in your description of NGC 2440. Interesting you saw it as greenish. At high power it looks like an alien face staring back at you! I can't recall seeing the central star either in my 12", at 381x.
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Old 17-02-2011, 06:56 PM
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Thanks Sab
I have occasionally seen a touch of green in brighter PNs. Not sure if it is an effect of the optics but it is present at all powers so I think not. Maybe atmospheric?
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Old 17-02-2011, 09:45 PM
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Originally Posted by barx1963 View Post
Thanks Sab
I have occasionally seen a touch of green in brighter PNs. Not sure if it is an effect of the optics but it is present at all powers so I think not. Maybe atmospheric?
Might be your darker skies, or even the differences in sensitivity to different wavelengths between each individual set of eyes. I myself haven't actually seen green in any PNe, except NGC 7009, which is a vivid light green. The most common colours by far I see are some shade of blue, white or grey. I remember a thread with several people chiming in with their visual descriptions of IC 418, all varying, which prompts me to think that one individual's eyes are more sensitive to a certain wavelength of light than another's.

Last edited by pgc hunter; 17-02-2011 at 09:57 PM.
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Old 18-02-2011, 07:21 PM
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Great set of observations Malcolm,

Interesting about seeing colour in pne I have seen colour both in M57 and M27 and when ever I look at m42(not pne) I always see colour.

Thanks for posting
Orestis
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Old 18-02-2011, 10:50 PM
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barx1963 (Malcolm)
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Ah Orestis! Those young eyes! Wait 'til you are old and decrepit and half blind!
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Old 20-02-2011, 11:53 PM
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Fantastic reporting (as usual!) Malcolm. Some wonderful star clusters detailed in your report for me to have a go at.
Reading part 1 of your current obs report, I took special interest in what you said about Sue French's observations. I was just reading her article today before I read your report and got excited to have a go at the pn's she suggested in her 10". If you can't find it in your scope, my chances would be less than yours, so you have saved me my sanity Malcolm, thank you. Must point my scope at the 6 star system (3 being visible) in Castor that she talks about. I really enjoyed her article this month. Les did a couple of super articles himself, tho I need a hundred times more apperture than what I've currently got for his achievements.

Can we all have permission to hate Orestis please? He has an unfair advantage over our larger appertures.
I'll be putting NGC 2440 on my next obs session and attempt to chase that colour.It is interesting what different eyes see, colour wise. When I first got my 6" scope and pointed it at the Orion Nebula, my 20yr old daughter told me it was green. Hubby nor I could see it, so I didn't believe her, thought she was loopy. Until I read up on it. Interestingly though, when I got my 10" there it was - very apparent, but as soon as I upped the mag. I lost the colour. I guess it needs to be distant, to get the benefit of colour. As for M57 Orestis- what colour do you see??? I only see shades of grey.
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Old 21-02-2011, 09:22 PM
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Thanks for your kind words Suzy and I am glad my efforts are encouraging you to find more objects. Please have ago at the faint lobes in NGC 2371-2 as my observing position is very poor for any objects that are low in the sky to Norh (streetlights!) or South (Princes Hwy!), and the main parts of the PN should be easy for you. I intend having a go at them at Snake Velley in a fortnight and would love to compare notes.
Don't worry about Orestis, we can all bask in his reflected glory!
See what you think of NGC 2440. Outside of stars and PNs the only colour I have seen was one splendid night I could see pink and green in M42. Hope to again sometime.

Malcolm
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Old 25-02-2011, 12:17 AM
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NGC 2440 at high power is a bloody creepy alien face to me. Observe this one from a remote site miles from the nearest human if you enjoy being creeped out. One of the most memorable DSO's out there.

I haven't seen M57 show anything other than grey. But it is fantastic at mags over 200x if seeing cooperates. M42 however is distinctly green, but that's not unusual among visual observers. I also see the Eta Carina Nebula as greenish.

The most richly coloured DSO out there would have to be NGC 3242, with its deep blue hues or the Homunculus Nebula with its vivid orange lusture.

Last edited by pgc hunter; 25-02-2011 at 01:10 AM.
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Old 25-02-2011, 09:39 AM
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hi everyone,

Just to clarify the colour is not stand out colour it takes time and it is there as a soft hue of aqua in m57 so it may not be apparant until close examination of the test subject and young eyes i am sure helps a lot thats why i am trying to enjoy astronomy as much as i can now.

Cheers Orestis
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Old 25-02-2011, 12:27 PM
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Large scope owners routinely mentions seeing a pink tinge to M42, along with green. I'd have to agree with this having seen the pink through my 17.5". Green I've seen in all my scopes, from my 2" to 'Odessius'.

I haven't seen M57, so I can't say.

Another planetary with a distinct blue colour is "The Blue Planetary" nebula NGC 3918 in Centaurus. It is a very vivid blue colour, and a bit of magnification, 100X +, will give the disk some size.

I'll have a go at 3242 this weekend.

What unnerved me though was The Rosette Nebula. I was finally able to nail this big bugger last new moon, and with an OIII filter. What I saw was it glowing with a violet colour! I was using my 17.5" f/4.5 scope with an RKE 28mm and the OIII filter.

Colour is a very difficult thing for our eyes with DSOs. Not only are these objects dim, but also in the mix is colour blindness, not just age. What is worst is 2/3 of all males are colour blind, from very, very mild through to no colour perception (very rare). And the wavelengths DSOs glow at, nebulae in this case, our eyes are least sensitive to, red and blue.
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Old 25-02-2011, 01:41 PM
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Quote:
Originally Posted by mental4astro View Post
Large scope owners routinely mentions seeing a pink tinge to M42, along with green. I'd have to agree with this having seen the pink through my 17.5". Green I've seen in all my scopes, from my 2" to 'Odessius'.

I haven't seen M57, so I can't say.

Another planetary with a distinct blue colour is "The Blue Planetary" nebula NGC 3918 in Centaurus. It is a very vivid blue colour, and a bit of magnification, 100X +, will give the disk some size.

I'll have a go at 3242 this weekend.

What unnerved me though was The Rosette Nebula. I was finally able to nail this big bugger last new moon, and with an OIII filter. What I saw was it glowing with a violet colour! I was using my 17.5" f/4.5 scope with an RKE 28mm and the OIII filter.

Colour is a very difficult thing for our eyes with DSOs. Not only are these objects dim, but also in the mix is colour blindness, not just age. What is worst is 2/3 of all males are colour blind, from very, very mild through to no colour perception (very rare). And the wavelengths DSOs glow at, nebulae in this case, our eyes are least sensitive to, red and blue.
NGC 3918 is an interesting one. Not only is it richly coloured, but can also show detail. I remember an article by Les in an issue of S&T describing a mottled disk and two handle-like appendages buldging out from the disk. Magnification has to be very high, Les described these features at around 600x I think.
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