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RA: 00h 13m 1.0149s
Dec: +72° 31′ 19.085″
Ch: MSA:24, U2:3, SA:1
Type: planetary nebula
Mag: B=11.7, V=11.4
Synonyms: H IV-058
Discovered in 1787 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a star 9th mag, surrounded with vF milky nebulosity. The star is either double, or not round. Less than 1' diameter."
Marling, J.B. (1986) In pursuit of planetaries. Sky&Telescope, Jun, 631.
Photo index by Jim Lucyk: Sky&Tel. 5/70 p310, Sky&Tel. 6/86 p631, Sky&Tel. 7/82 p19, Sky&Tel. 9/78 p200, Sky&Tel. 2/88 p151, Sky&Tel. 10/69 p227 (sketch), Astronomy mag. 2/83 p77, Astronomy mag. 9/85 p90, Deep Sky Monthly 1/81 p12.
The RNGC (Sulentic and Tifft 1973) notes that this is a 10.0 mag planetary nebula.
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes the magnitude as 12.4 and comments: "44" diameter; oblong with 11.5M central star; 13M star 2' to S."
Houston notes that this is a 10th mag planetary about 0.6' in diameter. Though located in a region devoid of bright guide stars, it was spied with his 5-inch Moonwatch scope.
Listed by the Herschel Club, described as "easy to observe, situated near two field stars. Round, bright nucleus fading a little to the outside of disk, greenish in colour. 8-inch, 43x."
James B. Kaler ("The Amateur Scientist", Scientific American, May 1992) notes: "Larry Mitchell and Phil Kuebler searched for NGC 40 with a 10-inch. They found the nebula easily and saw a slightly elongated halo and a prominent central star. With his 24-inch scope Mike Dennis could distinguish a hint if a greenish cast."
Stephen O'Meara first introduced me to the odd NE projection of NGC 40 a few years back at TSP, sort'a as an observing challenge. At the time, however, not even he was 100% sure of the correct size/orientation of the feature. So without knowing what to expect, I tried but didn't even suspect any odd "arm" protruding from the bright nebula with Mira. The very next TSP, on the other hand, I came armed with images galore, and I set out to see this mysterious object. I tried once again in the 16, but still couldn't quite convince myself of a positive observation. I then tried with a buddy's 25-incher, with which a couple of us suspected a row of 3 or 4 extremely faint stellarings at the correct position of the brighter segment of the "arm".
The entire feature does have somewhat of a "knotty" structure, however, I am still uncertain that what we saw was actually nebulous in nature and not just a couple of very faint, unresolved stars as were obvious elsewhere within the same field. The power used was about 661x, and no filter seemed to assist in the identification of the knots. Do let me know of any positive ID of the projection that you may make with the 24-incher though, because this thing definitely "looks" observable when compared to other nebulosity in the deep images. But we all know how that goes...
One of these days, I may be able to afford a scanner and possibly make some of these recent drawings available. The ones associated with this recent microstructure study are pretty damn intense, if ya' know what I mean... Because they are each being drawn at the highest useable powers and under only the best of conditions available to me at present. The project is taking forever to complete, however, the results have been quite phenomenal. It should make for truly kick-butt article--that is, if I can manage to squeeze more than one observation (and drawing) within a couple of pages ;-) HOWEVER, if Gary could possibly convince S&T to dedicate one entire issue to the observation of PNe (like Deep Sky #15 back in '86), the possibilities are quite endless ;-)
--That was a joke, guys... Everyone should be laughing at this point...
POSS: neb in pa13. m13 * 1' SW. m9-10 *s 3'.3 SSW, 3'.8 NE.
PK: photo has S up, W left.
15cm - consp @ 80x w/m9.5 * NE. 140x/195x: circ, 30" diam, reaching 1/3 or 3/8 way to m12.5 * SW. cen * vis @ 80x w/o difficulty, m10.5-11. *ings nr E, NW, & SSW edges. NE quad of neb wk; sl brtness variations over sfc throughout. DS filter good. UHC fair but not a great help; [OIII] seems to dim neb significantly. BS, 10Dec1990, Anderson Mesa.
25cm - seen @ 47x, quite br @ 180x. cen * consp. 1' diam, round. on SE is flashing spot vis w/averted vis. m13 * 1' NW. smooth w/one or two dk spots. dk immed around *; neb rises in brtness in the middle of the annulus.
30cm - 576x: 1'.2 NE of m13 *. unevenly br. cen * m11.5. brtning located in pa120 from cen *. elong E-W, 55"x40".
Observing site: Little Tycho Observatory
[0h 13m 0s, 72° 32m 0s] A 12mv star surrounded by a very faint 5" nebulous cloud. A real challange in urban skies. Mismarked on the finder chart.
Observing site: Little Tycho Observatory
[0h 13m 0s, 72° 32m 0s] Even with a finder chart, tough to find, stellar. I could see no nebulosity, just a 11mv star. There was an 7.5mv SAO star 1 degree north of it that was undetected and had no Tycho or Hipparcos counterparts.
The Messier objects
The Bennett objects
The Caldwell list
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