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View Full Version : Object of the Week, January 3, 2021 - NGC 891



Howard B
January 4th, 2021, 12:21 AM
Andromeda
Edge-on galaxy
Magnitude: 10.8
Size: 14.3’ x 2.4’
RA: 02 22 33
Dec: +42 20 57

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(image by Hunter Wilson, https://en.wikipedia.org/wiki/NGC_891#/media/File:NGC891HunterWilson.jpg)

A somewhat ghostly but very attractive edge-on galaxy, NGC 891 comes alive in dark skies. That’s not to say that it can’t be seen and enjoyed in less-than-ideal observing conditions, but a good view is more difficult to get. Even so, it’s worth the effort of returning many times to this out of the way corner of Andromeda to enjoy this iconic object.

As were many of the OOTW objects, William Herschel discovered what we now refer to as NGC 891. Exactly edge-on from our vantage point, it sports a fairly wide and diffuse dark lane bisecting it into equally bright parts. The two halves of the galaxy look to be exactly the same apparent size.

Like the bright parts of 891, the dark lane is a subtle visual feature in a light polluted sky, even in a fairly large scope. A clean, transparent night sky gives the best chance of seeing it well. The dark lane is a much more obvious feature under a true dark sky, while still being somewhat understated – but then that’s the character of the entire galaxy.

Interestingly, 891 seems to be much the same size and luminosity as the Milky Way, and studies indicate that it may be a barred spiral, although it seems to lack the characteristic X-shaped core thought to be typical of edge-on barred spirals.

Oriented northeast to southwest, 891 is seen through a pretty spray of Milky Way stars, which to my mind adds to the overall beauty of this field of view. Approximately 27 million light years away, these foreground stars help make the point that 891 is far in the background, which might be overlooked otherwise .

I’ve found that magnifications in the 200x to 400x range work best with 891, and that a binoviewer also presents a nice view. A binoviewer doesn’t always work well on deep sky objects, but on 891 it seems to slightly boost the contrast against the sky background.

Another observing aid is Jimi Lowrey’s 48-inch scope in West Texas! Although boosting the overall brightness of 891, it doesn’t add any specific details but does make the galaxy more substantial looking. It also brings out two small galaxies on either side of the galaxy. I don’t know if they’re far in the background or satellite galaxies of 891, but it’s fun to track them down if you have a large enough scope.

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The galaxy on the east side, north of the core, is MAC 0222+4222 and is listed at magnitude 16.5. The galaxy just off the west side of the core was easier to see, although I can’t find its designation or magnitude in the literature. Both galaxies needed fairly high power to see well, and my rough sketch here was meant to only show their positions (arrows) relative to 891. I haven’t tried finding these galaxies with my 28-inch yet.

My sketch below is from 2012, and represents the view though my 28-inch scope on a good, but not great night. I had views that were quite similar with my 20-inch, and I’m curious about the smallest scope anyone has used that gave a pleasing view.

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Give it a go and let us know!

Raul Leon
January 4th, 2021, 12:46 AM
Hi here's my observation from 11/6/2007: Ngc 891 fantastic edge on galaxy in Andromeda; magnitude:10.8 ; size: 14.3'x2.4' ; slightly bulged core with dark lane running through it. This galaxy is low surface brightness and needs a night of good seeing to get a good view. I used a 14mm Meade Ultrawide at 113x with my 14.5 Starstructure Dob f/4.3 4156

Bertrand Laville
January 4th, 2021, 06:06 AM
Hi All, happy new year for all of you !
I sketched this fantastic dark lane somme years ago both with a 10" and a 25".
Report here: http://www.deepsky-drawings.com/ngc-891/dsdlang/fr

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Uwe Glahn
January 4th, 2021, 07:36 AM
I've tracked down NGC 891 with many apertures up to date (4" bino, 5" bino, 8", 15", 16", 18", 20", 27", 36") but it is always a fun to observe the galaxy, when the skies allow it.

The dark lane was visible up to 8". My three attempts with 4" and two attempts with 5" don't bring a positive result.

The western companion 2MASS J02223046+4221370 was barely but clearly visible in a 16" telescope. The eastern companion 2MASS J02224186+4222417 was visible up from a 20" telescope.

sketch: 8", 114x, NELM 6m5+, Seeing III
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home (http://www.deepsky-visuell.de/Zeichnungen/NGC891.htm)

akarsh
January 8th, 2021, 10:03 AM
I've obviously observed this beautiful galaxy many times, but systematic logging has not been my forté. The first sketch I have is from Coorg in south India with my former Discovery 17.5" f/5 -- however, this sketch was not done on the field but reconstructed from memory of the eyepiece view while referencing a photograph, so it might not be an accurate reflection of the observation:
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Then I have two logs on the venerable 48" -- I think one of it might be the same night as Howard's beautiful sketch:

This is from 2014-10-25:
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NGC 891 and MAC 0222+4222 [2016-10-04]:
Wow! Lots of detail, wide dark lane! MAC galaxy is averted only but
nevertheless not too difficult to see.

Thanks to this OOTW, I just added the two 2MASS galaxies to my observing list, especially after being encouraged by Uwe's report of seeing one of them in a 16". Hopefully, I'll get a chance to give this a shot with my 18" some time in the future. (For now, sheltering in place hard).

Don Pensack
January 9th, 2021, 03:52 PM
Observation with the 12.5" at 166x, 228x, SQM 21.45
Long ellipse,moderately bright,center bulge a lot brighter than ends, ,dark lane bifurcating from end to end,one end slightly longer than the other, ends appear warped in opposite directions, dark lane appears curved in opposite directions at either end, very rich star field, at least 2 superimposed stars, quite a bit thicker than NGC4565, galaxy appears as if behind a wall of stars--fantastic impression! One of the most spectacular galaxies in the sky.

Dragan
January 9th, 2021, 05:41 PM
Whenever my turn comes around to post an OOTW, I can't help but wonder if we have, or will we ever, run out of showpiece objects.

Then Howard comes along and posts NGC 891 as an OOTW!? How has this never been selected?! :D

Howard B
January 9th, 2021, 09:39 PM
I was surprised too!

cloudbuster
January 12th, 2021, 07:12 AM
Hello to you all, this is my first entry on this forum, but some of you might now me from CN or the dutch "astroforum".

My recordings of NGC 891 in 2017:
Large galaxy, but also quite pale. Even from my dark site it was less prominent than I expected. Despite that, the outline was clearly visible against star filled background and the dustlane that crosses the surface was easily noted. Especially the latter is what made it a fine sight.

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location: Ezumazijl (Lauwersmeer)
telescope: 16 inch dobson (Sumerian Alkaid)
eyepiece: Pentax XW 10mm + Paracorr (181x)

BR, Martijn Straub (The Netherlands)