Object of the Week, January 19, 2020 – NGC 1579, the Northern Trifid

HII region
Perseus
RA 04 30 06
DEC +35 17 15
Size 7.8’ x 5.4’

“The main portion of the nebula is by far the brightest, with the other parts much fainter. Filters only dimmed the view so this much be a reflection nebula. Whoever came up with the name “Northern Trifid” wasn’t looking through an eyepiece. 270x”

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Those are my notes from a 2007 observation from my local observing site with my 28-inch scope, and I wanted to start with them because this observation makes the point that a telescopic view of NGC 1579 doesn’t at all give the impression that it looks anything like M20, the Trifid Nebula in Sagittarius. It’s misleading name aside, 1579’s distinctive character is more than enough to justify a good, long look through your own scope. By the way, don’t pay attention to the small-scale detail in my very rough sketches – they’re only broad pencil marks, and are representative of what most of my unfinished sketches look like.

Although labeled as an HII region, 1579 doesn’t respond to filters the way most HII regions do. Even so, it’s an active star forming region and is mostly red in the many images posted online. This one on the left was taken by Jens (details at https://www.cloudynights.com/topic/5...bula-ngc-1579/) and is compared to the more visually realistic grey scale DSS image on the right. The small nebulosity to the upper left is IC 2067, which I haven’t seen yet, if only because I didn’t realize it was so close by. Next time!

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Two older observations made with my 20-inch both describe 1579 as a “comet shaped nebula”. Sue French, in her Deep Sky Wonders book describe 1579 as being “easily spotted in my 10-inch reflector at 44x. At 118x, it spans about 6’ and appears quite irregular in shape and intensity” indicating that on a good, dark and transparent night 1579 is accessible to most amateur size scopes while showing a range of satisfying detail.

William Herschel came across this nebulous patch in December 1788, and cataloged it as GC 853: “pretty bright, very large, irregularly round, much brighter middle, 8th magnitude star 2 arcmin distant at position angle 350°" Hopefully your next view of it will be even brighter and more detailed.

Give it a go and let us know.

My own observation (the only one Ive made of this object so far):

12/6/18
EAGLE’S REST (gravel pit)
MOON: New
SEEING: 6
TRANSPARENCY: 7
SQM: 21.35
NELM: not checked
WEATHER CONDITIONS: temps in mid-40s, very little breeze, damp but not much dew, a few clouds low in sky that did not intrude on the areas observed

Others present: JO, DB, DR

All observations: 12.5″f/5 Discovery truss-tube Dobsonian, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV) unless otherwise noted

8:30
NGC 1579 (Per): This small nebula is pretty easy even without a filter. It’s very diffuse, with no “clean” edges to it, and brightest on its F side. With averted vision, there appear to be two separate lobes, with a fainter one SP the main mass as if there’s a dark lane separating them. The whole is elongated SP-NF and about 2.0′ x 1.0′. Averted vision also brings out a couple of stars near/at the center of the brightest part of the nebula (the central 0.5′). S of the nebula (and a very slight bit P) by 2.25′ is a faint double star, with 12.5- and 13.5-magnitude components separated by 0.3′, with the brighter P slightly N of the fainter. 2.5′ due N of the nebula’s center is an 11th-magnitude star; 9.5′ further N is another 11th-magnitude star. NF the nebula by 2.75′ is a 12.5-magnitude star with a 13.5-magnitude companion 0.75′ SP it. The brightest star in the field is due P the nebula by 12′ and is 7thmagnitude. S of the nebula by 12′ is a 9.5-magnitude star that’s the SP end of an arc or crooked line of four; the others in this line are 10th, 10.5, and 12.5 magnitudes and the line trails away to the F slightly N. The UHC filter, as I suspected, is of little help here, as this appears to be a reflection nebula. The only improvement is a very slight contrast boost in the separate lobe to the SP.

Interestingly Steve O'Meara also covers NGC 1579 in his secret deep book as object number 16

Hi here's my observation from 11/27/2014,
Ngc 1579 is a reflection nebula in Perseus aka The Northern Trifid ; fairly bright and elongated; OIII filter gives a little contrast but not a lot. Using averted vision and patience I began to notice on moments of good seeing a dark intrusion towards the center. I used a 8mm Ethos at 198x with my 14.5 Starstructure Dob f/4.3Attachment 3777

One of my favorite Herschel objects. I have these notes from seven years ago (16", dark blue zone site):

"At 45x it is a sizable nebulosity S of a star. A fainter star is on the NE edge. The nebulosity is diffuse but concentrated. The concentrated core is slightly boxy (longer dimension NS). 225x diminishes the nebula and brings out an even fainter star closer to the nebula’s center from the said fainter star. The nebula is now completely and widely separated from the stars. The long E edge is sharp as is the short S edge; they form a slightly obtuse angle. On the other sides the nebula is diffuse. It is concentrated toward the 2 sharp edges. OIII filter makes the nebula difficult to see."

This guy can show lots of detail Howard. Not a "real" Trifid but worth a visit.

I've logged three entries:
14", 200x, NELM 6m5+
relative small and faint, no positive filter response, brighter central part, dark lanes divided nebula in five parts, most prominent dark lanes NE and S, fainter outer parts

16", 180x, NELM 6m5+
interesting structures of the compact nebula, bright and divided with some dark lanes, no filter response

27", 293x-419x, NELM 6m5+
impressive RN, compact and bright with lots of dark lanes, beside the dark lanes dividing the central part to the outer parts, the central part itself fall apart three peaks with structure
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