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Cosmic Challenge: NGC 4361

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Cosmic Challenge: NGC 4361


April 2024


Phil Harrington


This month's suggested
aperture range

6- to 9.25-inch (15-24cm) telescopes










NGC 4361


12h 24.5m

-18° 47.0





Corvus, the celestial crow, flies low in the spring sky as viewed from the northern hemisphere. Located between the constellations Virgo and Hydra, it is easily identifiable by its compact shape resembling a perched bird. In ancient mythology, Corvus is often associated with the story of Apollo and his faithful messenger, the crow. According to Greek myth, the crow was sent by Apollo to fetch water in a cup, but instead dallied and returned late with a snake, blaming its delay on the snake's interference. Enraged by the deception, Apollo cast a curse upon the crow, condemning it to forever appear in the heavens with the cup and the snake as punishment for its deceit. The constellation Corvus was originally meant as a reminder of the consequences of dishonesty and the importance of truthfulness in both mortal and divine affairs.


The crow carries with it but one notable deep-sky object for backyard telescopes. Planetary nebula NGC 4361 is almost perfectly centered within Corvus's trapezoidal body. NGC 4361 was discovered by the German-British astronomer William Herschel on February 24, 1785.


To find this month's challenge, look about 1° south-southwest of Algorab [Delta (δ) Corvi] for a pair of 7th-magnitude suns.  Drop another degree to the south and you'll find a small isosceles triangle of 7th-magnitude stars.  NGC 4361 is less than a degree to their southwest.  The lack of bright stars in its immediate area helps it to stand out more prominently than it might otherwise.

Above: Evening star map. Credit: Map adapted from Star Watch by Phil Harrington

Below: Finder chart for this month's Cosmic Challenge.
Click on the chart to open a printable PDF version.



Most deep-sky observers are surprised by how large NGC 4361 appears in their telescopes.  Its apparent diameter, some 2 minutes of arc, is unexpectedly large for the genre.  At 54x, my 8-inch (20-cm) reflector shows it as a dull, round disk of grayish light surrounding a 13th-magnitude central star, as portrayed in the digitized sketch below.


Above:  NGC 4361 as seen through the author's 8-inch (20-cm) reflector.


But increase the magnification three-fold and add in a narrowband filter, and that unexciting disk is transformed into quite the sight.  With averted vision, the disk shows a stippled texture. Upon closer examination, the mottled image resolves into two dim tendrils of light extending away from the nebula's central disk and into its fainter outer shell.  These two regions curve away in opposite directions, one toward the northeast, and the other toward southwest.  The overall appearance, which is strongly reminiscent of a barred spiral galaxy seen face-on, makes NGC 4361 one of the most fascinating planetaries to study through amateur telescopes.


Above: Image of NGC 4361

Credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona, CC BY-SA 3.0 US, via Wikimedia Commons


Unlike many other planetaries, however, which demand the highest magnification that sky conditions will tolerate, NGC 4361 puts on its best show at more moderate powers, between perhaps 150x and 200x.  Anything higher and the faint structural details lose contrast against the outer gaseous shell.


Finally, do you see that faint galaxy in the upper right corner of the image above? That's MAC 1224-1841 according to Megastar. ("MAC" is the Mitchell Anonymous Catalog, compiled by Texas observer Larry Mitchell.) Also cataloged as LEDA 864871, this 16th-magnitude edge-on spiral is but one of several faint galaxies adjacent to NGC 4361. Each offers its own challenge through even the largest amateur telescopes. Try your luck with the half dozen "MAC" galaxies on the finder chart above. Let us know how you do them as well as with NGC 4361 in the comments column.


Until next month, remember that half of the fun is the thrill of the chase.  Game on!

About the Author:

Phil Harrington is a contributing editor to Astronomy magazine and is the author of 9 books on astronomy.  Visit www.philharrington.net to learn more.

Phil Harrington's Cosmic Challenge is copyright 2024 by Philip S. Harrington.  All rights reserved.  No reproduction, in whole or in part, beyond single copies for use by an individual, is permitted without written permission of the copyright holder.


  • John O'Hara and warddl like this


John O'Hara
Apr 04 2024 02:22 PM

I once spied this one with my 6" refractor from the old observatory site of the Oil Region Astronomical Society, then located in Two Mile Run County Park in Venango County, PA.  This was before the common use of nebulae filters, or at least before I owned any.  I remember how surprised I was that I could see the 13th magnitude central star.  At that time, I still believed the "canned" formula used to calculate the limiting magnitude of a telescope that I got from N.E. Howard's book, The Telescope Handbook and Star Atlas.  These days, I stuggle more to see the central star in that sized telescope, hopefully that struggle will be resolved with cataract surgery :-)

    • Sky King likes this
David Knisely
Apr 06 2024 05:01 PM

I like calling this one the "Lawn Sprinkler" nebula from those two opposite plumes in its outer shell. 

    • John O'Hara and Sky King like this

From 4-6-24, a single 5 minute image of NGC 4361 with a 8" EdgeHD, ASI533MC, and a IDAS NBZ-II filter. It does look like a lawn sprinkler!



Attached Image: 2024-04-07T16.21.48.jpg

    • Dave Mitsky, Jon Isaacs, John O'Hara and 1 other like this



Thanks for another challenge objects.  


NGC 4361 is one of those objects I like to look at briefly most nights when Covus is well positioned.  I have never logged an observation of 4361 but I have observed it many hundreds of times..


In honor of your challenge, I spent probably an hour spread over two nights just trying to eek out the detail I could see.  The skies were about 21.1 mpsas on the SQM-L.  Of course 4361 being favorably placed means Omega Centauri and Centaurus A are also favorably placed... I was using my 16 inch.  


Returning home, I decided to see if I could see 4361 from my urban backyard with my 10 inch Dob.  I measured the sky in the area at about 18.2 mpsas with an SQM-L.  Using an O-lll filter at about 70x, I was able to see 4361 through it was one of those type 2 amazing observations, i.e. amazing that I could actually detect it.. But it was there as a faint disk.


One nice thing about NGC4361 is that it is approximately 2.5 degrees from both delta and gamma Corvi so putting delta and gamma just outside the outer ring of a Telrad pretty much centers it. 



    • Dave Mitsky, John O'Hara, Knasal and 2 others like this

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