Yeah, I am back again with another report from the dark zone with the 17.5 inch. I went over solo this time as Mary had some other things to do. My main purpose was to clear out some fallen limbs at the back of the property and haul them to the burn pit at the local landfill. But that would be on Monday, and the forecast for Sunday evening was a bit questionable. Nonetheless, I made the 3.5 hour drive over and settled in to see what the sky would or would not do for me.
Come 2130 hours the sky looked rough. I did see a few stars, such as Arcturus and Sirius gouging their way through some thin clouds, but a great deal of the canvas was blank. So back inside I went, with the idea of giving it until 2300 hours to do my next check. However, about 2235 I couldn’t wait any longer so I donned my glasses and headed out the front door. Things were indeed on the upswing as numerous constellations were now visible, while some others were still struggling. I made the snap decision to bring the gear out of the garage and hurriedly set up my accoutrements.
Though I was not really dark adapted quite yet, I began this delayed journey about 2250 hours by swinging the scope back to Crater, which was cloud free at the moment. Turning the Interstellarum Deep Sky Atlas (IDSA) to chart 70, I aimed the scope at mag 4.1 Alpha Crateris. Let’s do this!
(Equipment used)
17.5 inch
f/4.5 dobsonian
Ethos 21mm (94x, 1.1° TFOV, 4.7mm exit pupil)
Ethos 13mm (152x, 0.7° TFOV, 2.9mm exit pupil)
XW 10mm (199x, 0.4° TFOV, 2.2mm exit pupil)
XW 7mm (283x, 0.2° TFOV, 1.6mm exit pupil)
(Treasure found)
NGC 3508 (Crater, spiral galaxy, mag=12.4, size=1.1’x0.9’, SBr=12.1):
This galaxy is a mish-mash of identifications in the
NGC/
IC. Discovered by William Herschel in 1785, it has also been listed as
NGC 3505 (John Herschel, 1836) and
IC 2622 (Lewis Swift, 1898). I swept it up using 94x and found it a small and somewhat bright oval. The disk was homogeneous to the eye and a dim 13.7 field star lay at its northeastern tip. Viewed with 152x it remained a strong presence in the field and evenly illuminated across its envelope. Then at 199x an intermittent stellar core was glimpsed at its center. (New)
NGC 3497 (Crater, lenticular galaxy, mag=11.9, size=2.6’x1.4’, SBr=13.2):
Another William Herschel discovery (1790), this lenticular also has a circuitous identification trail within the
NGC/
IC. It was also “discovered” by John Herschel (1835) and listed as
NGC 3528, Ormond Stone (1886) as
NGC 3525 and finally Lewis Swift (1898) and listed as
IC 2624. All this discrepancy is enough to give one a headache! For my part, I found it with 94x sharing the field with
NGC 3529 just to its south. This lenticular was somewhat bright and slightly large. Oval in shape it displayed a stellar core. Viewed with 152x the stellar core was surrounded by a small broader brightness, and with 199x it was a very strong presence within the field, easily out “glowing” its partner to the south. . (New)
NGC 3529 (Crater, barred spiral galaxy, mag=14.2, size=1.4’x1.1’, SBr=14.5):
The much weaker of the duo with
NGC 3497 to its north, it was small and fairly dim at 94x. Appearing as a thick oval shape, it was evenly illuminated across its disk. With 152x it was more obvious but remained weak. The view with 199x was similarly weak; however the galaxy now displayed a stellar core within its disk. This one was discovered by John Herschel 1835), but not to be outdone, Lewis Swift also “discovered” it in 1898 and it was subsequently listed as
IC 2625. So the duplications continue! (New)
NGC 3514 (Crater, barred spiral galaxy, mag=12.8, size=1.1’x0.9’, SBr=12.7):
Thankfully this galaxy only has one listing in the
NGC/
IC, per John Herschel’s discovery in 1835. I found it small and somewhat dim at 94x, exhibiting a homogeneous oval disk. The view at 152x was similarly diffuse, but it was more obvious within the field. Using 199x I spotted a very, very fleeting stellar core trying to pop through now and then. Overall it remained an evenly illuminated oval diffuse glow. (New)
IC 2623 (Crater, elliptical galaxy, mag=13.5, size=0.8’x0.6’, SBr=12.2):
Next up was this very weak elliptical, that I just barely glimpsed at 94x as a small diffuse mote. Dropping in the 13mm (152x) it was easily seen though it remained weak and quite diffuse overall. Using 199x diffuse oval was easily seen, but remained dim and homogeneous. This little elliptical was first observed by Herbert Howe in 1900. (New)
After getting a good foothold in Crater, the clouds decided to shut me down in that direction. Looking around I noticed Hercules coming up in the northeast more or less unaffected. So I swung the scope around and quickly found something nice and bright to serve as a distraction until my chosen target field cleared out again.
Messier 13 / NGC 6205 (Hercules, globular cluster, mag=5.8, size=20.0’, class=5):
I easily spotted the cluster in the 8x50
RACI finder then moved to the eyepiece where I was greeted with my first view for 2021. Large and bright at 94x, it was bejeweled with uncountable stars. The outer halo was well resolved as were myriad stars across the face of the disk. The globular had a three dimensional appearance with the resolved stars across its face underpinned by the denser central portion of its body with the smaller tight blazing core beneath that. There were multiple curving streamers of stars emanating from the central structure outward giving it a bit of a pinwheel appearance. Viewed briefly at 152x it was blindingly bright and with the variations in seeing it was a shimmering pool of stellar points overlaying the unresolved dense center. I have never known this object to disappoint visually, and it certainly did not this evening. This classical beauty was first observed by Edmund Halley in 1714, though it was Charles
Messier who popularized it as M13 when he recorded it in 1764.
NGC 6207 (Hercules, spiral galaxy, mag=11.6, size=3.0’x1.3’, SBr=12.9):
Almost half a degree northeast of the center of M13 I easily spotted this nice galaxy which sometimes struggles to be noticed because of the dominance of M13 in the field. At 94x it was a bright small flattened oval, with a very small inner lens of brightness with a stellar core pinned to its center. With 152x the galaxy was bright and beautiful. Its core was very strong and its disk extended further as dimmer outer regions came into view. This is an outstanding galaxy that unfortunately is too frequently passed over. William Herschel was the first to lay eyes on this pretty object in 1787.
After spending about 10 minutes with those two objects, I noticed that Crater was clearing out again – sort of anyway. So I swung the scope back there to reconnect with the celestial cup so I could continue my pursuit of some of its galaxies.
NGC 3456 (Crater, barred spiral galaxy, mag=12.6, size=1.9’x1.3’, SBr=13.4):
Back at it in Crater with another William Herschel discovery (1785), it was easily seen using 94x as a small and slightly dim homogeneous oval. I noted a dim 13.6 field star just off its northeastern edge. It was obvious at 152x and 199x, but remained evenly illuminated across its envelope. (New)
MCG -3-28-17 (Crater, spiral galaxy, mag=15.0, size=0.5’x0.5’, SBr=13.3):
Immediately south of
NGC 3456 I was looking for this weak little dust bunny, but at 94x it went unseen. Then at 152x it was only seen intermittently as a very weak and tiny diffuse spot. Going up to 199x it was easier, but still a weak presence. There seemed to be an intermittent stellar core trying to pop in from time to time. I went one more step up to 283x and it was a little more obvious but remained a very small and weak presence in the field with its intermittent stellar core struggling to be seen. (New)
IC 2627 (Crater, barred spiral galaxy, mag=12.0, size=2.4’x2.3’, SBr=13.7):
Picked up at 94x, this face-one barred spiral presented as a small round homogeneous disk. For its listed magnitude I found it pretty dim overall, and I suspect there may have been some high thin clouds moving through the field. At 152x it was easier, but still a weak soft glow. The view at 199x was still unimpressive overall though it was not difficult to see. (New)
NGC 3511 (Crater, barred spiral galaxy, mag=11.0, size=5.8’x2.0’, SBr=13.5):
Sharing the field of view with
NGC 3513, this somewhat large elongated glow was easily seen at 94x. It presented a thin somewhat bright soft glow with a dim field star off each tip, as well as an intermittent stellar core. Viewing at 152x it was quite obvious and I found it a curious sight. Dropping in the 10mm (199x) it was a pretty bright and large spindle that was more or less evenly illuminated except for its stellar core. The star off the eastern tip seemed brighter than its counterpart off the western tip. This is another William Herschel find, in 1786. (New)
NGC 3513 (Crater, barred spiral galaxy, mag=11.5, size=2.8’x2.2’, SBr=13.4):
Discovered by William Herschel during the same sweep as
NGC 3511, I found it a somewhat bright and subtly large homogeneous oval at 94x. It shared the field of view with
NGC 3511, almost 11’ to the NNE. Using 152x brought out a broad central brightness within the disk, which was reinforced at 199x. Overall it was a bright and easy target, but visually different than its field mate. (New)
NGC 3571 (Crater, barred spiral galaxy, mag=12.1, size=3.0’x1.0’, SBr=13.2):
Located with 94x I found it small and thin in appearance. Overall it was evenly illuminated and slightly bright to the eye. Viewing with 152x it was obvious within the field and displayed a broadly brighter center, which evolved into an intermittent stellar core at 199x. Discovered by William Herschel in 1790, it was independently discovered by Ormond Stone in 1886 and later added as
NGC 3544. However, Stone’s position calculation was in error and it was a duplicate observation of
NGC 3571. (New)
NGC 3667 (Crater, spiral galaxy, mag=12.7, size=1.5’x1.0’, SBr=12.4):
MCG -2-29-26 (Crater, spiral galaxy, mag=14.0, size=1.4’x0.6’, SBr=13.7):
The IDSA plots this object as a double system. Additionally
NGC 3661 lies within the same field 9.5’ to the west in the same field of view. The primary galaxy of the pair was first observed by William Herschel in 1786. As I was observing this object with 94x and 152x I had a single glow that was a bit extended and homogeneous. Overall it was dim and small to the eye. Moving to 199x, I was finally able to resolve the two galaxies as distinct objects.
NGC 3667 was the much brighter and slightly larger of the two. It lay immediately west of
NGC 3667A (or more appropriately MCG -2-29-26). The secondary galaxy was pretty dim and small, slightly oval in shape and evenly illuminated. Other than the main galaxy appearing brighter to the eye, they looked similar to one another in terms of appearance. It is suspected that they two are physically related as they have very similar recessional velocities and the secondary seems to show signs of an interaction. (New - 2)
NGC 3661 (Crater, lenticular galaxy, mag=13.1, size=1.6’x0.6’, SBr=12.8):
As mentioned in the previous entry, this galaxy was seen just 9.5’ west of the previous duo. A 1786 discovery by William Herschel, it unfortunately is duplicated in the
NGC/
IC as
IC 689 due to an erroneous re-discovery by Ormond Stone in 1889. After I finished studying the previous pair, I shifted my attention to this lenticular. Using 94x it was small and just slightly bright. Slightly elongated, it presented as homogeneous to my eye. At both 152x and 199x it was an obvious somewhat bright elongated glow that remained evenly illuminated across its disk. (New)
NGC 3591 (Crater, lenticular galaxy, mag=13.3, size=1.3’x0.9’, SBr=13.4):
I swept up this small and dim homogeneous oval using 94x. Its overall appearance changed little at 152x or 199x, other than being a little more obvious. This object is another discovery credited to William Herschel in 1786. (New)
NGC 3546 (Crater, lenticular galaxy, mag=13.3, size=1.5’x0.9’, SBr=13.5):
Small and dim, this homogeneous oval was still easily found using 94x. However, it really didn’t improve much at 152x or 199x. As with the previous object it was a little more obvious in the field as I increased magnification, but it still remained a weak oval diffuse glow. This object was not discovered until 1886 when Frank Muller first laid eyes on it. (New)
NGC 3663 (Crater, spiral galaxy, mag=12.5, size=2.1’x1.6’, SBr=13.7):
Next up was this spiral, which was another later discovery, coming in 1880 by Andrew Common. I located it using 94x, finding it dim and small lying next to two dim field stars (mag 14.7 and 15.1). It presented a diffuse oval glow, and that general appearance remained dominant even at 152x and 199x. (New)
NGC 3865 (Crater, barred spiral galaxy, mag=12.0, size=2.0’x1.5’, SBr=13.1):
Another Andrew Common discovery from 1880, this galaxy also has a duplicate identification of
NGC 3854 (Francis Leavenworth, 1886). I found it small, but slightly bright to my eye. It was a diffuse evenly illuminated oval glow. Using 152x it had a ghostly appearance, while at 199x I detected a concentrated non-stellar core brightness within its center. (New)
NGC 3866 (Crater, barred spiral galaxy, mag=13.2, size=1.7’x0.8’, SBr=13.4):
Almost 7’ southeast of the previous object I picked up this small and dim mote next to a mag 12.4 field star. More obvious at 152x it remained a bit dim, and presented a small homogeneous oval. Using 199x a stellar core was detected within the galaxy center. This is another example of an Andrew Common 1880 discovery by duplicated by Francis Leavenworth in 1886 due to a positional error on Leavenworth’s part. So it also shows up on the catalogue erroneously as
NGC 3858. (New)
NGC 3905 (Crater, barred spiral galaxy, mag=12.8, size=1.9’x1.4’, SBr=13.7):
Andrew Common strikes again with the discovery of this object in 1880. While I didn’t discover it, I did see it with 94x as a small and dim round homogeneous glow. Viewed with both 152x and 199x it remained a ghostly diffuse glow of lower surface brightness. (New)
NGC 3892 (Crater, barred lenticular galaxy, mag=11.5, size=3.0’x2.2’, SBr=13.4):
Another of William Herschel’s many discoveries, he found it in 1786. I found it to be small and a somewhat bright oval of small size. Observing with 152x and 199x it was an obvious feature within the field, and began to display a compact non-stellar brightness in its core region. (New)
NGC 3974 (Crater, barred lenticular galaxy, mag=12.9, size=1.3’x1.2’, SBr=13.2):
Swept up using 94x near the Crater-Corvus border, I found it small and dim. Round in shape to the eye, it was evenly illuminated across its disk. When viewed with both 152x and 199x it was easier to see as its contrast increased. However, it did remain small and homogeneous in appearance. John Herschel discovered this wee bit o’ fluff in 1828. (New)
NGC 3970 (Crater, lenticular galaxy, mag=13.7, size=1.2’x0.6’, SBr=13.2):
Just 3.5’ southwest of the previous object and easily in the same field, I saw it as a very dim and small oval of even illumination at 94x. Using 152x I suspected a stellar core was trying to pop into view, though the galaxy disk remained quite weak visually. Then at 199x I confirmed the stellar core, within the still very dim envelope. John Herschel also discovered this object in 1828 during the same sweep as
NGC 3974. (New)
NGC 3823 (Crater, barred lenticular galaxy, mag=12.7, size=1.5’x1.2’, SBr=13.8):
PGC 3093645 (Crater, spiral galaxy, mag=14.7, size=0.3’x0.2’, SBr=11.5):
The IDSA identifies these objects as
NGC 3823-1 and
NGC 3823-2. The secondary galaxy is more properly identified as PGC (or LEDA) 3093645. The primary galaxy was seen at 94x as a small and slightly dim rounded diffuse glow. It looked mostly the same at both 152x and 199x, with no internal brightness, just a smooth even disk. At this point there was no sign of the secondary galaxy. Dropping in the 7mm (283x) I was now picking up the intermittent presence of a tiny, non-stellar diffuse mote immediately northeast of the primary galaxy. This is exactly where I would expect to see it based on the plot in the atlas and images I viewed after the fact. John Herschel discovered the primary galaxy in 1836. (New – 2)
During my typical post observing research session, I ran into some conflicting impressions from my various sources. First the IDSA shows both galaxies, while Uranometria does not. Even the very deep Great Atlas of the Sky only plots the primary galaxy. Sky Tools 3 does not plot the galaxy, rather it shows a mag 13.6 star where the galaxy appears in images. Doing a search at NED/IPAC locates the object as does searching the SDSS Data Release 16 database. I finally found some basic data for it extracted from Steinicke’s RNGC. Anyway, I was quite pleased with this observation, and below find an image, showing the two galaxies courtesy of the Digital Sky Survey.
NGC 3959 (Crater, barred spiral galaxy, mag=13.2, size=1.2’x1.0’, SBr=13.2):
I was getting tired and it was time to wrap things up, so I selected a pair of galaxies in the northeastern corner of Crater to end the show. First up was this small and dim homogeneous oval, as seen at 94x. It remained a smooth diffuse oval even at 152x and 199x. It was nicely framed about halfway between two field stars (mags 13.5 and 14.6). This little oval dust bunny was discovered in 1881 by Wilhelm Tempel. (New)
NGC 3967 (Crater, lenticular galaxy, mag=13.4, size=1.0’x0.7’, SBr=12.8):
Just over 9.5’ southeast of the previous object, and sharing the field with it, I spotted this dim lenticular. Its general appearance was quite similar to
NGC 3959 in that it presented a small and dim homogeneous oval at 94x. Using 152x and stellar core did pop into view. However, even at 199x the galaxy remained weak within the field overall. It was also discovered by Wilhelm Tempel during the same observational session as
NGC 3959. (New)
A quick check of the time and it was past 0130, and I felt it was time to call it a night. I was very tired and chilly as the temps continued to drop steadily. Once I had all my gear back in the garage and I settled into my chair, a check told me the temperature was at 47° F (8.3° C). While that is not particularly cold, I was not dressed heavily and the chill and dampness of the air took its toll on a tired old man.
Thanks for coming along as I drank from the celestial cup and I hope to see you back out there again soon. Keep looking up friends.