TSS Monthly DSO Challenge – November 2024

[kt4hx]

The months seem to fly by at times, and thus we find ourselves in November, and fast approaching the end of another year. Over the past month we have had a fine distraction, or should I say focus. That would be the bright comet C/2023 A3 (Tsuchinshan-ATLAS). I certainly hope you all made an effort to check out this beautiful object. It is fast fading now, but was a gorgeous object. We easily saw it naked eye while driving down highway U.S. 50 rolling into Ely, Nevada while out west on vacation. Even with the naked eye it was an amazing thing to see as we moved down the road, looking out the driver’s side window.

Anyway, it is a new month and that means a new edition of the monthly DSO challenge here at TSS. Hopefully I can serve up some fun and interesting objects for you this month. As an added bonus this month I am including a Super Challenge object for each celestial hemisphere. In this case, each is a larger, low surface brightness galaxy. They both make for very challenging targets in particular for visual observers who have to deal with brighter skies. Imagers and those that pursue EAA or NVA methods might find them truly interesting objects to pursue. Anyway, I thought I would add them in for those that truly like a challenge under the night sky.

So let me introduce this month’s objects. For the northern folks we have a hat trick of open clusters, one each in Perseus, Cassiopeia and Triangulum. The super challenge object is also in Cassiopeia (IC 10). Our southern friends have more of a mixed bag, with a globular cluster and open cluster remnant in Horologium and a starburst galaxy in Reticulum. The southern super challenge is found in southern Cetus (NGC 247) just 4° north of the Cetus-Sculptor border. So with that, here are this month’s objects. I hope you will get out there and add these objects to your plans for the month of November.


Northern Celestial Hemisphere:

NGC 1342 (Perseus, open cluster, mag=6.7, size-14.0’, class=):
This cluster is located not quite 6° WNW of mag 4.0 Xi Persei (Menkib). It is a pretty object, standing out well in a rich star field, and consists of many stars of 8th magnitude and dimmer, being dominated by mag 8.4 HD 21773 at the NNW edge of its field, plus mag 8,7 HD 21728 just south of the field center. The double star ALI 516 (H. Ali) is obvious at the western side of its field. There are several lines of stars within the cluster, and sometimes one may see a vague “S” pattern dominating the cluster’s pretty field of stars. Overall it is a very nice cluster, though frequently overlooked by observers. Give this one a look and I truly don’t think you will be disappointed.

This was the last open cluster that William Herschel discovered, in 1799. He described it as "a cluster of coarsely scattered large stars, about 15' diameter."

NGC 663 (Cassiopeia, open cluster, mag=7.1, size=15.0’, class=III2m):
Not quite 3° ENE of brilliant mag 2.7 Delta Cassiopeiae (Ruchbah) one can find this fine cluster just 25’ southeast of mag 6.3 HD 10362. It is a rich and well detached cluster, standing out within its surrounding field. Its field is full of stars, with some visual counts reaching upwards of 75+ stars. There are many doubles within its field, the prominent of which are STF 151, 152 and 153 (Wilhelm von Struve) which form a line southwest to northeast line through the center of the cluster. This is indeed a fine object and easily located within Cassiopeia. Not only is the cluster pretty, but you are also getting the added bonus of three catalogued double stars within its field as well.

Though William Herschel is credited with discovery of this cluster in 1787, there is some sourcing that actually considers Caroline Herschel as the first to observe the cluster in 1783. Given its brightness and size, it is very likely that his sister was indeed the true discoverer of this object.

Collinder 21 (Triangulum, open cluster, mag=8.2, size=9.0’, class=III3p):
This cluster, while not as showy as the previous two object still has a pretty allure to its appearance. It is dominated by the mag 8.1 star HD 11142 at its southern edge. This star is actually a double catalogued as BU 1313 (Burnham). Another double star is at its northwestern corner, STF 172 (Wilhelm von Struve). The main attribute of this stellar grouping is a somewhat circular shape, particularly from the north around west to the southern end, while the eastern end is a bit more open. While not a showpiece by any means, it still has a curiously pretty appearance.

This object was highlighted by Swedish astronomer Per Collinder, who published a catalogue of open clusters in 1931. Eventually this object has been proven to be an asterism rather than a true cluster, as its stars are in a line of sight orientation rather than gravitationally linked. FYI, the mag 13.3 barred spiral galaxy, IC 1731, lay just 7’ north of the cluster.

Northern Super Challenge

IC 10 (Cassiopeia, irregular galaxy, mag=10.4, size=6.3’x5.1’, SBr=14.0):
The northern super challenge object is this irregular galaxy about 1.5° east of bright Beta Cassiopeia (mag 2.3). A member of the Local Group of Galaxies, it is only about 2.5 MLY distance from us. Very difficult if not nearly impossible from brighter locations, it does need some darker skies to be seen. For many, it will be a better imaging (or EAA) target than a visual one. Rest assured it challenges the visual observer. Its ghostly rounded glow can easily be passed over if one does not move slowly and deliberately during their search. This galaxy wasn’t discovered until 1887, when Lewis Swift found it as a very faint object. It was not recognized as a galaxy until 1935.


Southern Celestial Hemisphere:

NGC 1261 (Horologium, globular cluster, mag=8.3, size=6.9’, class=2):
This globular is located in the deeper southern sky constellation representing a clock, as described by Nicolas-Louis de Lacaille in 1756. It is a tightly packed globe of stars that with larger apertures can yield some decent resolution in its outer halo. However, its core is compact and bright and is difficult to resolve.

This object was discovered in 1826 by James Dunlop using his 9 inch reflector at Parramatta, New South Wales. He described it as a “very bright, round nebula”, but never mentioned any star resolution in his notes for the two times he observed the object.

NGC 1251 (Horologium, open cluster remnant, mag=9.1, size=14.0’):
This object is located about 2.5° south of NGC 1261, in eastern Horologium near the border with Reticulum. The grouping is dominated by mag 8.8 HD 20059 near its northern edge and mag 6.6 HD 20037 toward the southern edge of the field. However, these stars are not considered part of the dimmer grouping of 18 to 20 stars scattered in and around the field. It is more like the two brighter foreground stars are framing the cluster/asterism and clearly marking its position.

John Herschel discovered this object in 1834 while in South Africa. Many studies have considered this to be an asterism. However, a more recent study in 2013 determined that it is a very old metal poor open cluster remnant nearly 3,000 light years from our galactic disk.

NGC 1313 (Reticulum, barred spiral galaxy, mag=8.7, size=9.1’x6.1’, SBr=13.1):
Known informally as the “topsy-turvy galaxy” this object is a starburst galaxy, meaning it is undergoing active star formation. While this is due to an interaction with another galaxy, it appears to be relatively alone in the sky. Perhaps it has already absorbed a smaller galaxy, or its interactive neighbor is positioned behind the galactic disk from our perspective. Visually it is a beautiful example of a face-on barred spiral, though a bit distorted and chaotic. Depending upon one’s sky quality and aperture, the central bar may be glimpsed, as well as some knotty structure due to prominent HII regions of star formation. In images it is a stunning object.

This galaxy is another object credited to James Dunlop in 1826. While he observed this object three times, his positional data was incorrect every time. However, this was subsequently corrected by others who observed it after Dunlop, including John Herschel. This beautiful galaxy is located in the southwestern corner of Reticulum, near where it borders with Horologium and Hydrus.

Southern Super Challenge

NGC 247 (Cetus, barred spiral, mag=9.1, size=21.4’x6.9’, SBr=14.4):
This challenging galaxy was discovered by William Herschel in 1784. It is a member of the Sculptor group of galaxies, and is about 11.1 MLY distant from us. It is a ghostly appearing object, and can be very difficult if not near impossible from brighter areas because of its very low surface brightness. Under darker skies it comes into its own, especially with some aperture. To be honest, for most it is a. It is a better target for imagers or someone using EAA or NVA than for purely unenhanced visual observers. But if you like challenging objects to push your limits this will certainly do just that.


There you have it folks. This month’s DSO challenge is now in your hands. I hope you will take it on and add these objects to your plans this month. Good luck and we all look forward to hearing of your results.

[Bigzmey]

Nice selection of targets Alan, as always.

You got me intrigued with IC 10. It is on my list but I have not tried for it yet. I wonder if my binocular 100mm refractor would be a better tool for it than 14" SCT.

I have observed NGC 247 with 8" SCT from the Anza site 8 years ago. My sky was better then and at the lowest power (55x with 36mm EP) the galaxy appeared as a large and bright elongated oval. Black patch which has given the galaxy nick name Black Bottom Galaxy was well resolved.

[kt4hx]

I have observed IC 10 twice. The first time was with the 10 inch in 2013, the second was with the 12 inch using the 12 inch in 2016. This was at a different location in the county where we now have our other house. It was in a little darker area north of town. It was somewhat large in visual extent, evenly illuminated and not overly difficult. That said, it could be easy to pass over if one moves too quickly. I also found that using a little lower magnification worked better, and the first time I even used my Orion Sky Glow filter (an LP filter) and it did boost the contrast slightly. The second time the moon was in the sky at first quarter, and I was a little surprised I picked it up, but I most certainly did with no difficulty. Certainly observing skill is important, particularly when one has spent some time pursuing galaxies, so I don't think you will have any issues.

[John Baars]

Thanks for your efforts in finding and describing suitable objects of the Month. NGC663 seemed easy enough for a smaller telescope in severe light-polluted area's.

Yesterday evening I set up my OMC140, a 140 mm Maksutov. In order to cool it down properly I placed him outside in the cold three hours in advance. The moment I looked through it I knew why I like the instrument, the very fine proportioned stars. But in the meantime I realised why I have a love-hate-relation with it: its rather restricted field of view. I have become spoiled with easy-going fields of view of 2º or more in my refractors. Seeing and transparency were both not top.

I always compare NGC663 with M103. I like them both and visiting one means visiting the other, right behind each other. After all they are in the same field of view of the finder. I slightly prefer NGC663 because there seem to be some more stars, in a modest aperture that is.

In the final stage of the sketch I made the sloppy mistake by rubbing out the still wet ink of the brightest star while applying the background glow. It could be erased in computerprogram GIMP. Working too hastily does not work well. ( I wanted to post it the same evening)

Ink problem:

Ink problem.jpg (8.9 KiB) Viewed 876 times

Final sketch:

Click on the pic for a better view. Thanks for viewing.

[kt4hx]

Excellent finalized sketch John. I agree that this cluster is a true beauty. I have observed it a couple of times, first in 2010 with an ST120 that I no longer have, and then in 2016 with my 12 inch dob. In both cases it was a beautiful cluster. The voids or dark lanes shown in your sketch were particularly striking, breaking the cluster up into sections, which gives it a very curious character. Well done and I truly appreciate your contribution.

[helicon]

Speaking of galaxies in Cassiopeia I observed NGC 185 and 147 from the backyard perch with my 10" Dob pre-streetlight installation many years back.

I suppose IC 10 is not a satellite of Andromeda. Will have to give it a go Alan. Thanks also for the list!

[Bigzmey]

Thanks for your efforts in finding and describing suitable objects of the Month. NGC663 seemed easy enough for a smaller telescope in severe light-polluted area's.

Yesterday evening I set up my OMC140, a 140 mm Maksutov. In order to cool it down properly I placed him outside in the cold three hours in advance. The moment I looked through it I knew why I like the instrument, the very fine proportioned stars. But in the meantime I realised why I have a love-hate-relation with it: its rather restricted field of view. I have become spoiled with easy-going fields of view of 2º or more in my refractors. Seeing and transparency were both not top.

I always compare NGC663 with M103. I like them both and visiting one means visiting the other, right behind each other. After all they are in the same field of view of the finder. I slightly prefer NGC663 because there seem to be some more stars, in a modest aperture that is.

In the final stage of the sketch I made the sloppy mistake by rubbing out the still wet ink of the brightest star while applying the background glow. It could be erased in computerprogram GIMP. Working too hastily does not work well. ( I wanted to post it the same evening)

Ink problem:


Ink problem.jpg


Final sketch:

NGC 663 kopie 3 final.JPG

Click on the pic for a better view. Thanks for viewing.

Fine sketch John!

[helicon]

Also kudos on the sketch John, it's very nice.

[kt4hx]

Speaking of galaxies in Cassiopeia I observed NGC 185 and 147 from the backyard perch with my 10" Dob pre-streetlight installation many years back.

I suppose IC 10 is not a satellite of Andromeda. Will have to give it a go Alan. Thanks also for the list!

You are correct Michael. IC 10, while a member of the local group, is not a satellite of any other member galaxy. Of course, NGC 147 and 185 are satellites of M31.