UPDATE, 12/24/08: I have revised and enlarged the blog report you will find below, and have incorporated it into a new, full-length and referenced "Faint Fuzzies" website article on McNeil's nebula, which you may find here: a little Christmas present for my patient readers.
UPDATE: CONFIRMATION 12/29/08: What was first seen on 19 December 2008 in the Santa Cruz Mountains south of San Jose has been confirmed by me, using a C-11 telescope at Lake San Antonio, a dark sky site in Monterey County. Two new drawings and a detailed observing report have been added to my Faint Fuzzy article on the nebula: look for the section ADDENDUM: VISUAL CONFIRMATION near the end of this discussion.
My initial report of a tentative observation of McNeil's nebula was rushed into this blog on 20 December, about 15 hours after my visual observation. No other amateur sightings have been found on the Net during this rare visual appearance of the object, last seen by telescope viewers in 2004 (though photographs have been taken in September and October.) Now, the author has had a second sighting of SOMETHING corresponding in exact position with McNeil's nebula.
"McNeil's Nebula" was an independent discovery of a fuzzy patch near M78 by amateur astrophotographer Jay McNeil, back in 2004. The very interesting article he has written for the Western Kentucky Amateur Astronomers website may be found here.
In 2004 I had been "in between" telescopes, having sold my old 8" but not yet having acquired a replacement; so I missed the chance of seeing this nebula, which faded fast. It was a glowing patch of gas near the "eruptive" variable star V1647 Orionis, whose J2000 coordinates are (according to this VizieR reference page):
RA: 05h 46m 13.14s; Dec: -00d 06m 04.8s
The nebula has always been known to me as "McNeil's" object; but when I did a little research about it -- after having read Brian Skiff's notification to the Yahoo group "Amastro" that it was undergoing another outburst -- I found that this moniker was not at all recognized by the professional catalogues that I could search by means of NED, VizieR, or SIMBAD (though Sue French informs me that NASA ADS does indeed reference that name, and turns up these numerous cited papers: 42 as of this posting.) If that complicated link string doesn't seem to work, try this: http://tinyurl.com/9xvyrs
Jay McNeil first thought that he had imaged an entirely new object, never catalogued before and newly appeared: a particularly thrilling experience. But it soon turned out that the fairly large and bright nebula that his equipment had registered coincided in position with a very obscure object, a tiny faint speck already known for some time as Herbig- Haro 22 (HH22).
The numerous online articles I perused last week, before my attempt to observe the nebula, had not emphasized the complexities regarding WHAT it is, exactly where it was located, and its history. My first impressions, on looking into HH22 and related professional data, were that McNeil's nebula was an outburst and brightening of that object, known since the 1960s. But my friend and correspondent Sue French (contributing editor to SKY & TELESCOPE, and writer of the monthly column "Deep Sky Wonders") has very helpfully provided me with some digests of several papers, explaining that HH22 is thought to be along the line of sight with McNeil's nebula -- see the IAU announcement about IRAS 05436-0007, and the ApJ papers by Briceño et al. and Reipurth & Aspin (the last two in PDF form) for the details. I hope soon to be able to provide pertinent explanatory quotes in the present article, but a temporarily injured index finger has made typing very difficult for me today (12/22/08).
During the week just prior to my observing attempt, I found many papers referring to HH22, including the original Herbig-Haro Catalogue, awarding the newly- discovered nebula of 1966 the number HH22, which had been known for some decades before McNeil's distinct and separate nebula was discovered on his amateur image.
Among the diverse publications about HH22, a paper by Colin Aspin, et al., published in 2006 -- The 1966–1967 Ooutburst of V1647 Orionis and The Appearance of McNeil's Nebula -- in parts relates the early history, and has determined that the very FIRST known images of a nebular outburst at these coordinates date from the 1960s:
- ...The faint star is now designated as V1647 Ori and has been studied in great detail by numerous authors...
...V1647 Ori is known to have erupted once before. Mallas & Kreimer (1970) [The Messier Album (Cambridge: Sky Publ. Corp.)] include a photograph taken on 1966 October 22 that shows McNeil's Nebula at about the same brightness as during its current eruption. To further clarify the historical events associated with this object, we have examined the plate archives of both the Asiago Observatory and the Harvard College Observatory (HCO), which together span the last century, and we discuss below the historical outburst of V1647 Ori and McNeil's Nebula...
...Searches for previous eruptions of V1647 Ori, the illuminating source of McNeil's Nebula, used the Sofia Wide-Field Plate Database... The first plate showing McNeil's Nebula is dated UT 1966 October 22 01:22 and was likely taken only a few hours earlier than the one obtained by E. Kreimer. No evidence for McNeil's Nebula was found on plates prior to 1966 October nor after 1967 February.
... The HCO plate collection was inspected by M. Tsvetkov. Over 400 plates of the appropriate region in Orion were found in the HCO collection and visually inspected for the presence of McNeil's Nebula. These plates cover the period 1898–1974... We have found that McNeil's Nebula was not detected on any plate inspected from the HCO collection.
In conformance with the US Federal rules for "Fair Use" (permitting excerpts for the purposes of commentary, criticism, and education) I am posting below my composite versions -- rotated, matched, and scaled -- of Evered Kreimer's 1966 photo, and a recent 2008 digital image by Bernd Gährken: the irregular cloud looks remarkably similar, after decades of elapsed time during which the nebula was usually invisible from Earth's vantage point.
The outbursts of V1647 Ori -- HH22 and the line-of-sight but probably separate "McNeil's Nebula" -- are, then, rare, and of relatively short duration. Any interested amateur astronomer might well avail himself or herself of any opportunity to investigate an unusual appearance of a glowing nebula coincident with this faint variable star.
None of my atlases or star chart programs plotted McNeil's nebula, but I found that I could prepare customizable finder charts by using the designation HH22 via this page of the Deep-Sky Browser.
There is also a full page article on the SEDS website, which you may find here. I noticed than quite a few of the cited links are no longer working (sadly, including Tom Polakis' finder chart); and the object designation number used by page authors Hartmut Frommert and Christine Kronberg is the obscure "EQ J054614-00058", which was not recognized by NED, VizieR, or SIMBAD; thus, at first I was frustrated in my attempts to plot the object and all the faint stars of the immediate region (of course, the Palomar Sky Survey images do NOT contain a picture "McNeil's Nebula" since it was not currently illuminated.)
So, the solution was to use "HH22". VizieR chronicles it here, and gives these J2000 coordinates:
RA: 05h 46m 14.2s; Dec: -00d 05m 31s
According to this paper by M. Kun of the Konkoly Observatory in Budapest -- "Early spectroscopy and photometry of the new outburst of V1647 Ori -- "The previous outburst of the star [was] between 2004 January and 2005 October... A new outburst of the star was announced on 27th August 2008."
The star's magnitude on red plates is very faint (on the order of 17th) so there is practically NO chance that it would be visible in a typical amateur telescope, probably not even a large one, as the central frequency of the sudden outburst is at about 6570 Å, as you can see in this chart in Kun's paper. But the intense radiation excites the gases in the region of the star: that is likely what made the nebula HH22 visible in 1966, plus McNeil's nebula visible in 2004... and now.
For about a week after I read Brian's notice, M78 was not well placed as the Moon was up when the region of McNeil's nebula was high in the northern California sky. But as the new Moon approaches -- Saturday 27 December 2008 -- I grew very impatient. The first clear night I experienced that coincided with my availability was Friday, 19 December. And so, even though some clouds were passing over quickly, I loaded my 10" Orion f/4.7 reflector into the car and headed up to my regular mountain-top observing site in the Santa Cruz range, south of San Jose.
By the time I reached my spot at 3,400 feet altitude, the clouds were WORSE. A particularly dense and pesky one was seated right over the top of the peak, and I was still in the periphery of it. Ugly streaks of milky glow defaced most of the sky at 9pm. I sat in the car, dejected, shivering in the 31 degree F temperature, and listened to an old Sherlock Holmes radio mystery show, stopping it every ten minutes to step outside and scan the heavens.
After 10pm a very noticeable sense of clearing was evident, so I began setting up the equipment. I had prepared for this ONE object, but had done it thoroughly, making several printed star charts from TheSky VI, and the Deep-Sky Browser page; plus correct and mirror-image negative laser prints of an excellent labelled image that was linked via the SEDS article. I used the "Irfanview" program to convert the picture to monochrome and produce an enhanced negative view, and printed it in correct and mirror-image orientation.
I made two drawings of the region of M-78, and the area where I think I may have seen McNeil's nebula. They do tend to match fairly well with the star chart printouts and the reversed picture; but I am not yet finished with all the checking I intend to do, particulary by means of Aladin (to get the stars near HH22 documented and check their magnitudes: some do not show up in TheSky's database.)
What I publish below was done only up to about 3 pm on Saturday 20 December 2008, about 15 hours after I made the observations described.
Please note that this is provisional. I do not even know if ANYONE else, anywhere, has visually spotted this nebula during the recent 2008 outburst (though pictures have been taken, notably by Rick Johnson, as cited in the discussion thread "McNeil's Nebula is BACK!" on the ASTRO website's astrophotography forum.) A second sighting by me was obtained on Sunday night 28 December 2008 -- details to follow soon -- which definitely increases my confidence. But readers should naturally feel some skepticism until another person's visual report is available.
Letter to Jaakko Saloranta
Unfortunately the humidity was very high during this observing session on late 19th/early 20th December 2008: the nearest online weather station about a mile away reported that the humidity was hovering around 80%, the temperature being just below freezing (my scope, table, charts, and observing book were all covered by sleet when I finished at 12:25 am.) The moisture on the paper made it difficult to write; I had an opportunity to make the sketches while the sheets were still dry, but great difficulty later in trying to copy down details. I recovered them about 90 minutes later from recent memory, and immediately sent an email to my friend and colleague Jaakko Saloranta in Finland, with a copy to Sue French. It's easiest just to quote this email, and then -- following it -- to present the two drawings, which I've very quickly scanned and notated.
- Jaakko & Sue:
I just got back from the mountain-top. In short, I saw *something* and it might have been McNeil's.
But I'll have to carefully match my drawing to the reversed, corrected digital image; McNeil has done a recent one that I can use.
My notebook got so wet that my pencil could barely write in it; what I scratched is going to need some reconstruction. Let me just summarize very quickly:
Top of mtn was covered with a cloud that took an hour to depart. Put up 10" f/4.7 scope at 10:30 when the streaky clouds all around me started to clear. Was working on the field before 11 and matched the stars in the plot I'd made with TheSky (which has a very strange designation and outline for M78 that was VERY confusing. And the photos and images of M78 were about equally confusing, for it never looks at all like that to the eye!)
At last I had chosen the correct version of my negative print out of McNeil's own picture and had matched it to the field. Around 11 pm I began sensing something in the nearby region, a spot of nebulosity -- maybe a 1'+ faint patch -- that was surely N2064 (which was very obvious.)
The area where the outburst is around the variable star wasn't immediately visible to me, using 200, 240, and 340x; but as the sky improved and nearing midnight, with M78 almost at transit, the region was moving over the darkest part of my sky, with a NELM I estimate to be better than 6.2; eventually I decided that I *was* seeing something faint and vague with AV, maybe an arcminute "puff" of stuff that I tried to draw. In doing so I lost enough dark adaptation that it disappeared. But I was seeing stars that were fainter than the ones I printed out from the HGC, and quite few of the faint ones in McNeil's digital image that are down around 13-14 mag. I finally finished two drawings of the region and decided that either I *did* see the nebula; or a sort of mixture/average of the two faint stars that are close to each other (could actually be a double); or just part of the texture of the whole region (as there is quite a trail of stuff drifting away from M78 to the SW.)
I haven't read any reports of McNeil's now being visually spotted, but apparently it is being photographed -- err, digitally imaged! -- effectively.
If I *did* actually see it, I'd say it was harder and fainter and more vague than Gyulbudaghian's nebula!
To 'calibrate' my conditions at 11:50 I tried the Horsehead: it was FABULOUS! I could see its shape, straight-on (no ambiguity at all!) with various magnifications from 48 to 92x, with the H-Beta filter. At 71x, there was a very distinct ridge of glow around the "head" and IC434 was very bright, well defined, and almost "sparkly". It was a much better view than I had last month with the same scope.
All six of the common members of the Trapezium were visible at 240 and 160x, a little better and more consistently at the lower power -- but the brighter stars were pretty coarse looking, and the faintest of the six was not seen all the time: so the seeing was not spectacular.
And, IC 429 *was* visible, but not nearly as well as on the spectacular night in October (I think) when I made four drawings with the same scope, and saw many of the faint stars around it that range up to 16th mag.
I would say, however, that based on the Horsehead, the sky was indeed quite transparent.
So there is probably a *chance* that I did see it -- but I consider this VERY, very tentative. It was so abominably faint that I fear that most people would either ignore it or refuse to accept it as having been perceived at all; but I tend to be a bit bolder in accepting my own boundary observations. I'd very much like to try it again at least a couple of times, now that I am familiar with the star field at varying magnifications.
Tomorrow (err, later this morning!) when I scan the drawings I made, I'll forward them to you, to see if they refute or support my assertions.
Best,
Steve
Sketches of M-78 and McNeil's Nebula (tentative)
First, I used the paper printout of the negative version of the image cited above that is linked from the SEDS article, and oriented it to match the view I was able to see in my scope. M-78 was easily visible in my 9x50 finderscope, and showed up beautifully in the main instrument, even without a light pollution rejection filter.
When I was comfortable with the surrounding star field, I increased the magnification, at first trying my 3.5 mm Hyperion [341x, 0.7 mm exit pupil, ~12' FOV] with, and without, the SkyGlow filter. I thought I might be seeing something "fluffy" with extreme averted vision and concentration: it was somewhat larger than NGC-2064, but much fainter and more diffuse. It seemed a bit easier to perceive in my 5 mm Orion Stratus [240x, 1.1 mm exit pupil, ~17' FOV] with no filter, and that's what I used to mark the chart; then I made two drawings: of M-78, and the region immediately to the west that encompassed the field that surely must contain McNeil's nebula.
Since the nebula was SO faint, I did not bother even to try testing the UltraBlock or OIII filters; the magnification I was using was too high for them to be useful.
I have scanned the marked printout below: note that I have circled the faintest stars that I seem to have been able to perceive, and to make that easier to note here I have colored those markings light green:
The curved line represents approximately the field-stop when I had positioned M-78 to the edge of the field in order to get several bright stars out of the way.
On the plot above, I marked two faint stars that are quite close together -- separated about 19 arcseconds, according to TheSky VI -- which are positioned approximately one minute east of HH22. However, when I made the sketches below, the use of my faint red light seems to have prevented me from discerning them again so that I could draw them. I wondered: did I really see them? COULD they be seen?
So I fired up Aladin and the NOMAD survey, and obtained the visual magnitude ratings. The stars are (according to the Hubble Guide Star Catalogue): GSC 4768:696, 15.1 mag, and GSC 4768:171, 15.8 mag. But I am well aware that the GSC ratings are not necessarily correct "visual magnitude" values. Aladin reported that they were, per the NOMAD survey, 14.25 and 15.56 visual magnitude, respectively. I am pretty sure that I did see these: because later, when I checked IC-429, I could discern flickers of a 15.93 Vmag star that I have used as a test for determining conditions to discern that nebula.
The Aladin composite screen dump I made from the measurements of these two stars, and HH22, is found, below, following the next paragraph. The thumbnail is a reduced-sized version to fit this page, and will be unreadable; you may click here to see it full-sized. Note that while HH22 is plotted, it wasn't registered on the film (since the Palomar DSS image was photographed when the variable star V1647 was quiescent.)
Note also that the red magnitude ratings given for HH22 (17.25 to 18.5) are not for "McNeil's Nebula", but rather for the star V1647. I don't believe that anyone has derived any sort of range of visual magnitude rating for McNeil's nebula, since it is so variable (changing from quite bright to invisible over time); furthermore, MANY deep sky nebulae have no given visual magnitude data, those no longer being relevant in professional astronomy.
Having marked the printed image-chart with what I could discern by eye, I next made two sketches: of M-78 and NGC 2064, and then by allowing the scope to drift to the west without recentering it, of the region of McNeil's nebula. I show the same star -- GSC 116:147 -- on both sketches.
Unfortunately the picture is larger than the available screen size here on this blog; so you may click here to view it full-size. What is shown below is half-size, so the labels may not be intelligible.
Ideally, I would not conclude that I have definitely SEEN this nebula without doing a followup observation. What I seemed to perceive was extremely faint, even though it was probably at about the correct position (and it did 'move along' with the field as it drifted); but it could be (a) an illusion, or wishful thinking; (b) some of the "fluff" of the outlying portion of LDN 1621, encompassing M-78; or (c) perhaps the vague perception of the sum, or average, of the barely-perceived light from a few faint stars.
I shall continue to investigate. It would be helpful to find any other visual acquisitions of this object; so far I have found only images posted-- not visual sighting reports -- during this recent outburst since August, 2008.
CONFIRMATION: Using my C-11 telescope, between 11:30 and 1 am on Sunday night 28 December, and Monday morning 29 December, 2008, I obtained at Lake San Antonio in Monterey County, California, a second corroborating view of the phenomenon, with a somewhat higher confidence of the faint stars in the field, suggesting that the purported 'sighting' was neither a clump of faint stars, nor an illusion: but a real and palpable patch of extremely faint nebulosity. Two new drawings and a detailed report of this confirmation have now been posted: see the section ADDENDUM: VISUAL CONFIRMATION near the end of this article.
Addendum: Sue French has just sent me her OLD report of seeing McNeil's nebula from 2004 (so please note that it probably won't exactly parallel what might be seen during this present fall/winter 2008 reappearance):
Steve,
Here's my observation:
2-18-04, WSP, 8pm EST, 254/1538mm Newt (Dan Joyce mirror), 9mm Nagler, Seeing: good, Transparency: good
McNeil's nebula near M78 is visible as a small oval smudge. Joe Bergeron confirms. Disappears with narrowband filter. Brighter spot in south end. Only the northern star in the nearby pair can be glimpsed. Clearly visible are NGC 2067 surrounding a mag ~10 star and straggling SW for ~8'. Even brighter is oval NGC 2064 ~3'x2' NNE-SSW.
Not very thrilling or detailed, but there you have it.
Clear skies, Sue
ADDENDUM, Monday 12/22/08: Saturday evening, after I had finished writing up my asserted visual observation 'claim', I wished to establish its date independent of MY own website; so I registered and logged on to a fairly recent astronomy forum that has a discussion thread about McNeil's nebula and its reappearance (I won't give the link for reasons that will be explained.) After all the rigmarole of altering Javascript settings and adjusting downward the browser permissions toward "less safe", I attempted to post the link to this present article. But the forum editor PREVENTED this, informing me that I was 'too new' to be given permission to cite an URL; so I merely informed their readers that they could use Google to search for my post. Very soon afterward, the forum moderator and the 'sysop' both welcomed me publicly and told me that they would love to see my report and pictures. But, it is now two days later, and I still am frustrated at every attempt, not being given authorization to cite my article; and I consider this very annoying and frustrating, so I'm giving up. I'll stick with THIS blog of mine, and my own websites, thank you!
Srw
[posted 3:45 pm 12/20/08, with additions and/or corrections at 6:13 pm, 6:35 pm, and 7:52 pm on 12/20; at 11:51 am, 1:03 pm, 3:38 pm, and 6:07 pm on 12/22/08; 1:46 am and 3:05 pm on 12/23/08; at 5:17 pm on 12/24/08; at 11:19 am and 8:53 pm on 12/29/08, and at 3:16 pm on 1/06/09.]
Copyright Statement: The original contents of this article are Copyright © 2008-9 Stephen R. Waldee - All Rights Reserved. All trademarks or copyrights are properties of the original copyright holders. The author Waldee requests that you do not copy these articles elsewhere, particularly into lists, blogs, web pages, databases, or astronomy compilations in any form. The primary reason is that these articles are essentially raw data from our observing logbook, consisting of reports and sketches that have not yet been thoroughly fact-checked, intended as preliminary drafts for future "Faint Fuzzies" articles that will benefit from extensive corrective research.
