TheSkySearchers

Hello friends and welcome to the new edition of the TSS Monthly DSO Challenge. This month the primary plane of the Milky Way will be shifting a bit to the west and some of the autumn (or spring depending where you live) sky will begin to make its appearance. The night sky always gives us both a sense of comfortable familiarity and a sense of renewed expectation each month. We say goodbye to some old friends and hello to other old friends. That is one of the many great things about this hobby; we meet and make many good friends both down here and up there! So I wish you good luck and hope you enjoy the pursuit and results thereof.


Northern Celestial Hemisphere

Messier 15 / NGC 7078 (Pegasus, globular cluster, mag=6.3, size=18.0’, class=4):
As the winged horse begins its climb in the eastern sky, the bright star Enif (Epsilon Pegasi) marking its nose is often what we see first. Just over 4° northwest of the star one can easily scoop up this fine globular cluster. The bright field star HD 204862 (mag 6.1) lies in tight proximity to the cluster, only about 17’ to its east. The cluster is smaller than the showpiece M13 in Hercules, but it is still intensely bright in the eyepiece. It is easily seen in binoculars and even magnified finders. In dark skies it may even be glimpsed with the naked eye. It sports a very bright and very tight core, which does not give up any resolution. However, its outer fringes and inward toward the core can be resolved with enough aperture and magnification.

This beauty was discovered in 1746 by Jean-Dominique Maraldi while tracking Comet de Cheseaux of 1746. Interestingly the cluster has undergone core compression whereby many of its stars have been pulled inward, giving it one of the most densely packed cores of the Milky Way globulars. An interesting aside to this globular is the fact that it contains a planetary nebula, known as Pease 1 or more officially as PK 065-27.1. It has an apparent magnitude of around 15.5 and a miniscule diameter of around 3.0”. This object is an extreme challenge for those with larger aperture and darker skies, and requires very precise image based finder charts to locate with certainty.

NGC 7243 (Lacerta, open cluster, mag=6.4, size=30.0’, class=IV2p):
The constellation representing the celestial lizard is frequently ignored by many observers. While it is true that it does not contain any Messier objects, that does not mean it is void of observable DSOs. This cluster was discovered by William Herschel in 1788. In his notes he described it as "an extended cluster of coarsely scattered vL (i.e., bright) stars, in the direction of the parallel nearly; about 16' long." Its large field is indeed scattered and coarse, but it still is a curiously pretty cluster. There are enough stars strewn across its field that intrigue the eye with numerous sub-patterns and geometric shapes. Give this object a try and see if you enjoy it as much as I do.

NGC 7331 (Pegasus, spiral galaxy, mag=9.5, size=10.2’x4.2’, SBr=13.3):
This bright and beautiful spiral was discovered by William Herschel in 1784, when he noted it as “pB, cL, E, lbM” (i.e., pretty bright, considerably large, extended, little brighter in the middle). Located in northwestern Pegasus, just over 1° south of its border with Lacerta and just under 4.5° NNW of the double star Eta Pegasi (mag 2.95 and 9.87), this is truly a fine galaxy for both visual and imaging. Not particularly difficult from areas of moderate light pollution, it truly shines in dark skies as do all diffuse and extended objects. It sports a very bright core set within its tilted oval disk. Viewing dark lanes and mottling within the disk is also possible.

Interestingly NGC 7331 is the dominant galaxy in a small unrelated grouping of galaxies known as the Deerlick Group. They are also affectionately known as the “dog and its fleas.” The dog (NGC 7331) is a foreground object, while its fleas on its back (immediately east of the “dog” are more distant galaxies physically unrelated to one another that form a line of sight grouping. The four smaller galaxies are NGC 7335 at mag 13.3, NGC 7336 at mag 14.5, NGC 7337 at mag 14.4 and NGC 7340 at mag 13.7. If you have medium to large aperture and have decent skies, see how many of the little itchy critters you can pick up. This group makes a fine imaging target as well, presenting an interesting contrast of large and bright with small and dim.


Southern Celestial Hemisphere

Melotte 227 (Octans, open cluster, mag=5.3, size=50.0’, class=II 2 p
Discovered by Philibert Jacques Melotte around 1915, this very deep southern object was deemed an open cluster initially. However, some studies have concluded it is merely a non-related line of sight asterism. Also known as Collider 411, regardless of whether it is a true cluster or random happenstance of stars, it is a curious and obvious object. Totaling about 40 stars, it is best observed using lower magnification due to its large angular size of around 50 arc minutes. At -79° declination, it is indeed a deep southern object. However, if it graces your sky, turn a scope its way to see how many stars you can pick out.

NGC 6818 (Sagittarius, planetary nebula, mag=9.3, size=0.45’x0.4’, SBr=7.2):
Nicknamed “The Little Gem” this bright planetary is located less than 2.5° south of the Sagittarius-Aquila border and just over 41’ NNW of our third southern challenge object, NGC 6822. First observed by William Herschel in 1767, he wrote the following description of this marvelous object: "a small beautiful planetary nebula, but considerably hazy upon the edges; it is of uniform light throughout, considerably bright. Perfectly round, 10 or 15" in diameter. My brother Jacob being in the gallery, I showed it to him." In my experience with the object, I found it slightly of our round, with an obvious pale blue color. Like Herschel, I find its edges soft, but unlike him, I find the light across the disk not totally uniform, with its eastern side being brighter. I invite you to observe and/or image this object to see how your impressions compare.

NGC 6822 (Sagittarius, barred irregular galaxy, mag=8.8, size=15.5’x13.5’, SBr=14.5):
Discovered in 1884 by E.E. Barnard, he initially considered it a variable nebula. Barnard studied this galaxy extensively over the years and published his work "NGC 6822, A Remote Stellar System" in 1925. Additionally, it is affectionately known as “Barnard’s Galaxy.” It also carries a duplicate identifier in the Index Catalogue, IC 1308 due to some identification errors by later observers. This barred irregular galaxy is a member of the Local Group of galaxies, and lies about 1.63 million light years distant. It is a challenging object visually because of its extended angular size and resulting low surface brightness. Seen from a darker area, it can appear as a diaphanous brightening against the sky. With some aperture and study, one may detect some of its brighter HII regions as well. In images it is a beautifully delicate visual entity that tickles the imagination, and makes a very curious study.


There you have it for this month. I hope you will add these objects to your regular plans observing and imaging plans, even if you’ve visited them previously. They are all well worth additional looks with a fresh sense of curiosity and wonder. Good luck and keep looking up there, you just might surprise yourself as to what you can see.

Thanks for the list Alan! I am hoping the forecast holds up for tonight for me. It was supposed to clear out by about 8pm, but it keeps moving back, now it is 10pm.

If I am able to get out, your August and September targets are on my list.

KingNothing13 wrote: ↑Thu Sep 02, 2021 12:13 pm Thanks for the list Alan! I am hoping the forecast holds up for tonight for me. It was supposed to clear out by about 8pm, but it keeps moving back, now it is 10pm.

If I am able to get out, your August and September targets are on my list.

Good luck with your outing Brett. If you get your clearing, then certainly objects from both months will be in play for you. We are happy that the remnants of Ida have finally cleared out of here, as its supposed to be clear tonight here as well, with good transparency. I am out the dark site house (to meet an HVAC guy) and will spend the night so I can take advantage of the first clearing in a while.

kt4hx wrote: ↑Thu Sep 02, 2021 12:32 pm

KingNothing13 wrote: ↑Thu Sep 02, 2021 12:13 pm Thanks for the list Alan! I am hoping the forecast holds up for tonight for me. It was supposed to clear out by about 8pm, but it keeps moving back, now it is 10pm.

If I am able to get out, your August and September targets are on my list.

Good luck with your outing Brett. If you get your clearing, then certainly objects from both months will be in play for you. We are happy that the remnants of Ida have finally cleared out of here, as its supposed to be clear tonight here as well, with good transparency. I am out the dark site house (to meet an HVAC guy) and will spend the night so I can take advantage of the first clearing in a while.

Same basic story here, without the HVAC - we had the outerbands of Ida - so just rain, no wind. Stopped overnight sometime. It is bright and sunny right now, but it is supposed to cloud up again at some point, then clear out again.

We had similar after Fran as well, but the smoke in the atmosphere made it pretty murky.

Thanks for this monthly challenge.

I observed NGC 7331 and adjacent galaxies late in the night about one month ago. Very interesting target(s) indeed. Those adjacent galaxies are almost ten times behind NGC 7331. When observing this area of the sky, it's also worth attempting the Stephan's Quintet, about 1 deg away from NGC 7331.

Thanks for the list Alan and I recognize some old friends. Hopefully it will clear over the weekend. With a waning moon, things will get better over the next week or so.

Nice list Alan, many thanks!

What a great idea.

Piero wrote: ↑Thu Sep 02, 2021 1:10 pm Thanks for this monthly challenge.

I observed NGC 7331 and adjacent galaxies late in the night about one month ago. Very interesting target(s) indeed. Those adjacent galaxies are almost ten times behind NGC 7331. When observing this area of the sky, it's also worth attempting the Stephan's Quintet, about 1 deg away from NGC 7331.

Thank you Piero. Stephan's Quintet, or more formerly Hickson 92, Arp 319 or VV-288, is indeed a fine tight knit grouping and very worthwhile visiting if one has some aperture and especially coupled with darker skies. In particular the pair that constitute NGC 7318 (PGCs 69260 and 69263) are tough to split with smaller apertures. Below are my notes from an observing session a couple of years ago at our dark site house with the 17.5 inch. As you suggested, in that case after observing the "Deerlick Group" I moved on to Stephan's Quintet.


Stephan’s Quintet / Hickson 92 / Arp 319
Since I was in the neighborhood, I decided to turn the 17.5 inch on Stephan’s Quintet. Only observed from here previously with the 10”, I was able to resolve this small clump of galaxies as four dim but distinct glows. I was unable to split the two cores associated with NGC 7318 A and B however. Tonight would correct that though.

NGC 7320(Pegasus, spiral galaxy, mag=12.6, size=2.2’x1.1’, SBr=13.5):
Easily the brightest of this clump, it was easily discerned as a somewhat bright oval, displaying some broad brightness in its center. It clearly dominated the field at all magnifications (110x to 297x).

NGC 7319 (Pegasus, barred spiral galaxy, mag=13.1, size=1.7’x1.3’, SBr=13.8):
Just north of NGC 7320 I noted this slightly bright oval. I found it homogenous and quite diffuse at all magnifications. Though clearly evident in the field it played second fiddle to its brighter neighbor to the south.

NGC 7318A (Pegasus, elliptical galaxy, mag=13.4, size=0.8’x0.8’, SBr=13.0):
Just off the northwestern tip of NGC 7340 I picked up the dual bright cores of the NGC 7318 pair. The “A” portion is more properly known as PGC 69260, and its envelope overlaps that of the “B” part. Basically they appeared as a pair of bright round cores in a larger diffuse halo.

NGC 7318B (Pegasus, barred spiral galaxy, mag=13.1, size=1.4’x0.9’, SBr=13.2):
The core of the “B” part of this double, also known more properly as PGC 69263, was clearly evident just east of the “A” core. Again, the two halos were so intertwined as to be one larger diffuse presence housing two bright eyes peering back at me. But for me, this was the first time I’d resolved the two galaxies to the point that I could discern their two separate cores.

NGC 7317 (Pegasus, elliptical galaxy, mag=13.6, size=1.1’x1.1’, SBr=13.8):
Southwest of the NGC 7318 duo slightly separated (by a mere 1.5’) I scooped up this round and slightly dim object. It did display some modest central brightness, but was mostly diffuse in appearance. There was a 12th mag field star involved at its northwestern edge.

PGC 69279 (Pegasus, spiral galaxy, mag=15.5, size=0.6’x0.4’, SBr=13.8):
Just over 4’ WSW of the center of Hickson 92, I managed to pick up what is sometimes referred to as NGC 7320C. Though not part of Stephan’s Quintet, it was in the same field of view. Noted at higher magnifications (199x and 297x) as a very dim and small oval. It was quite weak and difficult visually.

helicon wrote: ↑Thu Sep 02, 2021 2:36 pm Thanks for the list Alan and I recognize some old friends. Hopefully it will clear over the weekend. With a waning moon, things will get better over the next week or so.

Thank you Michael. I hope you can get out there while the moon is out of the way!

Kanadalainen wrote: ↑Thu Sep 02, 2021 5:25 pm Nice list Alan, many thanks!

What a great idea.

Thank you Ian, and it is terrific to see you back here again. Your input has been missed. Hope you get a chance to observer/re-observe the objects in the August and September challenge lists.

Just one, M15, wide field. I wanted to include Enif since it is used to sweep up M15 visually. Used my 135mm Rokinon for 20 minutes of exposure. Had to shrink the image to 66% full size and crop to one quarter full frame to fit into site max pic size limitations.
Capture specifics, Rokinon 135mm f2.0 telephoto at f2.8, IR cut filter, Asi1600MC-cool camera, gain 200, offset 50, temp -15C, no darks, barks, quarks, flats, cats, or bats, just raw OSC. Guided with 4 inch Meade SCT at 2 sec rate, all riding on Meade 16 LX200.

Clear skies,
Steve

Thanks Steve, appreciate your submission. I nice wide field presentation to give perspective of the globular's position relative to Enif.

The Deer Lick and Stephan's Quintet are excellent challenges on a dark, transparent night.
With my 8 -inch SCT I can see three of the "fleas", but will try for that fourth one on an exceptional night...

For Stephans Quintet, I can't split the A and B components of NGC 7318; I can discern four galaxies in this group.
Th objects are also visible as a single fuzz through my 4-inch refractor.

Arctic wrote: ↑Mon Sep 20, 2021 5:15 pm The Deer Lick and Stephan's Quintet are excellent challenges on a dark, transparent night.
With my 8 -inch SCT I can see three of the "fleas", but will try for that fourth one on an exceptional night...

For Stephans Quintet, I can't split the A and B components of NGC 7318; I can discern four galaxies in this group.
Th objects are also visible as a single fuzz through my 4-inch refractor.

Thank you Gordon. Agree, these are fine challenges for both equipment and observing skills. I know from another location in our dark area using my 10 inch I could also not splice the NGC 7318 duo. Of course from the dark site house with the 17.5" it was not difficult (as one would expect). Pegasus is a true treasure trove of galaxies and for those who really enjoy galaxy hunting it is a welcome sight in the fall, along with Andromeda.

Just had a go at NGC7243 and M15 with my new binoculars. I had a look at Stellarium first to check their positions.

The open cluster was easy to find sitting as it does between Caph and Deneb. And a great find it was too! The range of star colours is brilliant. I looked them up in Stellarium afterwards and they include 5 Lac at B-V 1.67 to 2 Lac at B-V -0.09! I scanned around the area a bit and found a mini Ursa Minor standing on its handle, comprising a couple of Lacerta stars and a few Andromeda stars!

M15 was directly above Jupiter sitting at the apex of a flattened triangle with Enif to the left with the δ and γ Equ pair to the right. Again, the colour difference in these stars is awesome! Estimating a central point above these two, with both just out of my 4.8° FOV, I could just make out the faint fuzzie. It was in the position I had identified earlier, between three mag 6 and 7 stars in a micro Summer Triangle sitting where Sulafat would be.

Then I had another look at Jupiter because you just have to! I could see two moons and again, same as the other night, the disc of the planet not quite round. I purposely didn't look up the moon positions beforehand but the view left me wondering if my eyes are dodgy or if I need to get some more practice focusing. So I came in to check the moon positions. Turns out I saw Callisto to the East, Europa to the West and it was both Io and Ganymede close to either side of the edge of the disc. With the GRS just coming into view, it is a great photo opportunity!

Excellent challenge Alan! I didn't try for the galaxy because I don't think I could see a mag 9 galaxy and I didn't think I could remember three star hopping maps in my head!

Thanks

Regards

Graeme

Very nice report Graeme. You did very well with the objects using your binoculars. With Jupiter, if I only notice two moons through binoculars or a finder, I typically assume the other two are either in front of or behind the planet. Agreed, Jupiter always looks flattened at the poles due to its high rotational velocity.

I would not expect you to remember three hops, that is why they make charts! While there are several objects I can find without consulting a chart, there are far, far more that I cannot! As I age, my retentive memory weakens.

kt4hx wrote: ↑Wed Sep 29, 2021 9:51 pm I would not expect you to remember three hops, that is why they make charts! While there are several objects I can find without consulting a chart, there are far, far more that I cannot! As I age, my retentive memory weakens.

My aged, tattered, trusty Philips star charts book, from my Dob days is still packed away. But I'm with you on the age thing!

The laptop does the job and saves having to wear a red head torch! But it's still too bright even turned right down!

Regards

Graeme

Graeme1858 wrote: ↑Thu Sep 30, 2021 5:45 am

kt4hx wrote: ↑Wed Sep 29, 2021 9:51 pm I would not expect you to remember three hops, that is why they make charts! While there are several objects I can find without consulting a chart, there are far, far more that I cannot! As I age, my retentive memory weakens.

My aged, tattered, trusty Philips star charts book, from my Dob days is still packed away. But I'm with you on the age thing!

The laptop does the job and saves having to wear a red head torch! But it's still too bright even turned right down!

Regards

Graeme

Agree it is indeed difficult to dim electronics to the point where some impact to dark adaptation isn't felt. But I fully understand the utility of using an electronic atlas as there is much more flexibility than with a printed one. I still rely on my detailed printed ones and might never change, though I have considered doing so.