I am presently writing an article on the only planetary nebulae in Mensa on K1-27.
Question please. Has any amateur actually observed this Mensa object?
My basic text on this object so far is;
K1-27 / ESO 33-33 / PK 286-29.5 / P NG 286.8-29.5 (05570-7540) is a faint but (the only) sizeable PNe in Mensa, which was found by Kohoutek in 1977. Now listed as K1-27, this is a confirmed high excitation PNe of significant age. In size, K1-27 covers some 46 arcsec across
The specific area where this faint nebulous object lives is easily found, but revealing the little beastie in not for the faint of heart or those with poor observing city sites or in having mediocre vision - except of course for imagers. Its elusive nebulosity was earlier missed by many observers, and was not even found by Karl Heinze, because it lay well outside the the range of his “He2-” catalogue of Milky Way the haven for most known PNe along the galactic plane.
The white dwarf central star has been identified as 16.7 magnitude, being a probable physical pair whose component is 0.56 arcsec in PA 315 degrees according to Ciardullo et al. (1999). This is the white-dwarf WD 0558-756, being a rich DO-type planetary nebula nucleus. An exact position for the planetary is 05h 57m 02.10s -75° 40' 21.0". Distance is about 1.2 kiloparsecs.
The PN is mag 16.1 according to David Frew and Kent Wallace tried unsuccessfully to see it twice.
The attached 28' by 28' image is from wikisky.org
HD41188 is the mag 8.4 star at top right.
The PN is mag 16.1 according to David Frew and Kent Wallace tried unsuccessfully to see it twice.
The attached 28' by 28' image is from wikisky.org
HD41188 is the mag 8.4 star at top right.
Thanks Glen,
I have attached a colour-corrected image of this PNe…
Sadly the nebula is no good for [O-III] because of its old age (nebula-wise). The problem with observing it is the nearby 8th magnitude star in the field just swamps the faint nebulosity. So far I've heard of no one observing it with an occultation bar, which might help.
It also has a strange box-like appearance and a 'Z-shape', which is unusual.
I just spoke with Andrew Murrell on the phone and we have put this on our "to observe" list next new moon in the 25" Obsession from Bucketty. We will post some notes on our success, or lack thereof. The skies at Bucketty are the equal of Ilford and it should be doable in the 25.
I've not seen it but I'll give it a go and we'll see. You say no OIII, does it shine in H-Beta at all or is this one of those nasty NII ones?
At what wavelength is mag 16.1 ?
If Karl Heineze missed it, it must be a doosey.
The problem with this PNe is that it is old. The failure is because of the less amount of ultraviolet the illuminate the nebula. Needless to say the excitation of the nebula gas is diminished somewhat - in both H-beta and O-III. As to your comment on the NI and NII, the signature of old age is their rise against more familiar wavelengths
In my investigations of this object so far, it should be visible in 25cm or 30cm , but it seems it is not so.
Now as I have trouble climbing ladders these days, I'd appreciate both positive and negative observations! One of the reasons for the question here is because it is not common listed, and frankly, seems one of only a few PNe DSO's that has been so neglected.
In the end, I was hoping for another He2-434 (my fave southern planetary), but by Glenn's statement, it appear to be more difficult to see. (Wish we had the French observer Yann Pothier, but he can't see the object. Our guys are really good observers, but the advantage he has in observing so high up in the French alps (1.6 km, mind you), he'd kill this beastie (or not) in no time!)
Je sacre par Dieu, Sacre bleu!
As for the reason Henize missed it because it was outside the range of the southern survey.
Regardez en avant pour entendre votre succès d'échec !!!
(Look forward to here your success of failure)
Last edited by Enchilada; 25-11-2009 at 03:32 AM.
Reason: the text said what it did mean to say not meant.. Might have fixed. Perhaps not??? You know what I mean….
I just spoke with Andrew Murrell on the phone and we have put this on our "to observe" list next new moon in the 25" Obsession from Bucketty. We will post some notes on our success, or lack thereof. The skies at Bucketty are the equal of Ilford and it should be doable in the 25.
Cheers,
John B
Thanks. I look forward to hear your responses and your successes or failures. So far away from the Milky Way… I think I like your chances.
Pity I have trouble climbing ladders! Best of all, it is becoming the best time of year to observe it!
(Note: ASNSWI members will be getting an little Chrissy surprise soon which relating to planetary nebulae. It will probably be distributed to the rest of the folks, just a wee bit later! Bit of the hush-hush at the moment, but it should be really good news!) Back scratching at last works well with me!!!
Last edited by Enchilada; 25-11-2009 at 08:17 AM.
Reason: Milly Way, sounds like a girl I once knew….
I don't know of any observations of this PN by David Frew.
He gives the distance as 1.7 kpc. (5,500 l yrs)
He wrote a PhD thesis called Planetary Nebulae in the Solar Neighbourhood: Statistics, Distance Scale and Luminosity Function. (March 2008)
It can be downloaded (20Mb) here: http://geosn.com/
K1-27 seems to be brightest in H alpha.
I don't know of any observations of this PN by David Frew.
He gives the distance as 1.7 kpc. (5,500 l yrs)
He wrote a PhD thesis called Planetary Nebulae in the Solar Neighbourhood: Statistics, Distance Scale and Luminosity Function. (March 2008)
It can be downloaded (20Mb) here: http://geosn.com/
K1-27 seems to be brightest in H alpha.
Looking at this, all these low values is why K1-27 is so difficult to spot.
I'd think the [O-III] filter should make a marginal bit of a difference, though the Hβ should be next to useless.
The Hα is not overly different than the same ratios to other lines seen in other PNe.
Thank you very much for providing that spectral info -- FWIW I agree with your conclusion that OIII is probably the best bet out of a bad bunch.
If I get the chance, of course I'll throw every filter I've got at it but considering Kent's non-observation with 50cm (for those that don't know, Kent Wallace is one of the most experienced PNe observers in the world), I'd say my chances with the slightly smaller aperture are pretty close to zero.
I just had a look for this PNe with my 12" Dob at 190x. K1-27 was not visible.
I saw the mag 15.4 star on its southern edge, but only on and off, mostly off.
It is a good night, with stars visible almost down to the horizon with the naked eye.
Maybe the Astronomiks UHC filter will work well on this target
Quote:
Originally Posted by Enchilada
Thanks Glen,
Sadly the nebula is no good for [O-III] because of its old age (nebula-wise). The problem with observing it is the nearby 8th magnitude star in the field just swamps the faint nebulosity.
Quote:
Originally Posted by ngcles
Hi Enchilada & All,
You say no OIII, does it shine in H-Beta at all or is this one of those nasty NII ones?
At what wavelength is mag 16.1 ?
Les D
Quote:
Originally Posted by Enchilada
The problem with this PNe is that it is old. The failure is because of the less amount of ultraviolet the illuminate the nebula. Needless to say the excitation of the nebula gas is diminished somewhat - in both H-beta and O-III. As to your comment on the NI and NII, the signature of old age is their rise against more familiar wavelengths
Quote:
Originally Posted by glenc
K1-27 seems to be brightest in H alpha.
Hi all,
I will heed the advice and try this target unfiltered first up.
I have an Astrononiks UHC filter as well as the Lumicon and DGM Narrowband (UHC) filters and I am thinking the Astronomiks UHC may just work pretty well on this target. Most commercial UHC/Narrowband filters are fairly tight in their bandpass characteristics. The Astronomiks on the other hand is a much "softer" UHC filter and has 100% bandpasses right through the OIII and H-Beta bandwidths. Most importantly it has a 96% bandpass through the H-Alpha range. Most other UHC filters block this H-Alpha range out. This filter may just be well suited to this particular target.
No. It is certainly galactic. Most PNe are tiny in the Large Magellanic Cloud. I.e. A typical PNe is ~0.2 pc across while the LMC is 48500 pc. away. The distance, according to David Frew's thesis is 470±115 pc., meaning that this planetary is among the closest to us!!
As it has a PN G Number - the G, incidentally, standing for Galactic, agree with this idea.
Spectra K1-27
.
