Astronomical dark was scheduled for about 2151 hours, so I rolled the big
My first targets, while the sky was still darkening and my eyes adjusting, was to be the northern globular clusters featured in the May edition of the
(Equipment used)
17.5 inch
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)
Already knowing the cluster is located almost halfway between Arcturus (Alpha Bootis) and Cor Caroli (Alpha Canum Venaticorum) I aimed the scope using the Rigel. Moving to the
Dropping in the Ethos 13mm (152x) it was a grand visual treat. Not quite symmetrically round in shape, it was a huge glowing ball of stars, with countless resolved at its fringes into the core area. The core itself was an intensely bright glow that underpinned the whole visual experience. I noticed several strings of stars emanating from the cluster’s body. In particular I noticed one curving flow coming off the northern side and turning to the northeast. Another string of stars of which I took note of was one that was thicker closer to the core and thinned out as it strung out to the east. This cluster is a perennial favorite, and it is easy to see why. Give it a try yourself and enjoy the view!
A short 5° star hop to the east of M3 is this more challenging globular. Easily passed over if you are not looking for it, its lack of any significant core concentration means its light is spread out evenly across the disk, reducing its visibility. I easily spotted it at 94x as a large ghostly orb lacking any concentration of brightness across its face. As the weak seeing was changing, various member stars would pop in and out of view across the disk, with a persistent hazy backdrop of the unresolved constituency. Viewed at 152x it presented a large and subtly bright ball that seemed a little ragged around the edges. Countless stars were again popping in and out of view across the disk with the constant backdrop of a hazy glow. I did notice a strand of dim stars flowing from the northeast side and wrapping around to the south. While not a showpiece, its eerie appearance is nonetheless attractive and curious.
Next up was this nice cluster about 57’ northeast of Alpha Comae (Diadem). The cluster was just picked up in the
As
The final of three globulars in this constellation, is a small little thing. Found almost 6.5° northwest of Denebola (Beta Leonis), using 94x it displayed a tiny concentrated brightness in the core, with perhaps four or five stars resolved in its outer fringes. When viewing with 152x and even 199x, it was bright but quite small visually. Upwards of 10 stars were being seen in its outer halo and across its face. Interestingly, my last observation was from our typical suburban backyard about eight years ago with my 10 inch. In that case, it did not appear clearly as a globular cluster, but brought to mind a small elliptical galaxy as no stars were resolved. This one is challenging because of the combination of its visual magnitude and its small angular size.
WBL-374 (
This cluster comes from a paper entitled The Catalog of Nearby Poor Clusters of Galaxies by White, Bliton, Bhavsar, Bornmann, Burns, Ledlow and Loken (1999). The paper introduces “a catalog of 732 optically selected, nearby poor clusters of galaxies covering the entire sky north of −3° declination.” There is some cross-over with Abell clusters, Hickson groups, Cfa (Center for Astrophysics) and Yerkes catalogues. While the number of galaxies listed in the data comes from the paper, I had to estimate the angular size of the group using Sky Tools 3 (ST3). I located the cluster field using a chart I’d prepared in ST3 as well as charts in Interstellarum and Uranometria, which display several of the member galaxies. Orienting myself to the layout of the small glows I was picking up at 94x, I immediately went to 152x for the purposes of identification and observation.
Designated as WBL 374-010 within the cluster group, this face-on spiral lies at the southern part of the cluster field. Observed with both 152x and 199x it presented a small out of round homogenous glow. Overall it was slightly bright to my eye despite the presence of the star within the field. (New)
Carrying a duplicate identifier of
Also carrying a duplicate catalogue number,
Just over 7’ north of the close pair of elliptical galaxies just described, I also picked up this little round cotton ball. Small and slightly bright seemed to be the theme at this point and this one also fell into that slot. However, it remained homogeneous at both 152x and 199x. The cluster designation is WBL 374-007. (New)
Not quite 4’ further north I noticed, you guessed it, another small and slightly bright elliptical. However, this dust bunny displayed what appeared to be a stellar core at 152x. Using 199x it seemed to be subtly off-set and later I found there is a foreground star of magnitude 8.6 imposed on the disk that was likely what I initially thought was a stellar core. The cluster designation is WBL 374-008. (New)
Southwest of
In the same field as the previous object, I also tried to pull out this even fainter compact galaxy. This object is not actually a member of WBL-374 as it is too dim to fit the parameters of the study. But since it was there, I tried. I felt I was seeing something at a few instances at 283x, but I suspect that was more a case of averted imagination and wishful thinking. Based on the extremely tenuous impression I was getting, I discounted the observation and it did not go into the log. After the fact I looked at Steve Gottlieb’s notes for this object and noticed that it was difficult for him in a 24 inch, so that reinforced my skepticism. So count that one as a swing and a miss, but that is okay because we never know if we don’t try.
Now back to actual cluster members, this one is recorded as WBL 374-011. I spotted it 5’ southeast of
Nudging slightly more southeast I picked up a mag 8.8 field star, then directed my attention about 6’ ENE to this lenticular. Its designation within the cluster is WBL 374-012. I found it small and dim at 152x, ever so slightly oval in shape and generally homogeneous. Using 199x I picked up an intermittent stellar core popping in and out of view. (New)
North of the previous object and carrying a cluster designation of WBL 374-013, I noticed this soft elongated glow within the field. Small and dim, it presented an intermittent stellar core at 199x as well. (New)
PGC 38278 (
Here we have another case of averted imagination and wishful thinking conspiring to try and trick me with another non-member of the cluster. This object is immediately west of
Nudging NNE about 15’ from
About 3’ southwest of the previous object and in the same field was this slightly dim and round mote. Observed with both 152x and 199x it presented a stellar core within the disk. Its cluster designation is WBL 374-018. (New)
Next in this group was the small and round dim glow of this compact galaxy. Known within the cluster as WBL 374-017, it displayed a stellar core at 152x and 199x. However, I suspect this was a foreground 10th mag star imposed very near the center of the galactic disk. (New)
Nearly 3’ south of the previous object was this small and slightly dim round glow with a 12th mag field star just off its northwestern edge. Generally homogeneous at 152x, a stellar core was seen at 199x. Its cluster designation is WBL 374-018. (New)
The previous four cluster members formed a subtle curve of galaxies north to south, with this member and the following object sat slightly separated about 3’ to the west of the mid-point of this curve. This elliptical was round visually and slightly dim to the eye. It presented a stellar core at both 152x and 199x, and carries the designation of WBL 374-014 within the cluster. (New)
The final cluster member I observed is WBL 374-015, immediately east of the previous object. The two disks were nearly in contact visually. This elongated strip of slightly dim light was small in visual extent and evenly illuminated across its envelope. The two made an interesting contrast packed so closely together with very distinctly different shapes. (New)
After finishing up with the WBL 374 cluster, the sky had shifted enough that
Turning to chart 81-right in the IDSA, I star hopped about 3.5° southeast of Beta Corvi (Kraz). The cluster was easily found lying next to a triangle of three field stars (two of 8th and one of 9th mag). With 94x it presented a bright and slightly small irregularly round glow. A few stars drifted in and out across its disk, which displayed a modest central brightness. Viewed with 152x perhaps a dozen stars were now seen overlaying a slightly dense core brightness and general haziness of the cluster’s unresolved members.
Alessi J1309.4-2338 (Hydra,
Since I was in the area, I noticed in the IDSA (chart 81-left) that this previously observed
About 19’ southeast of Psi Hydrae I easily spotted this small and somewhat bright rounded glow using 94x. Homogeneous to the eye, it was just northwest of an 8th magnitude member of the
In the western part of the
This slightly bright oval was spotted about 14.5’ SSW of the previous object. It was diffuse and evenly illuminated at both 152x and 199x. (New)
Next up was this little dust bunny about 10’ northwest of
The final galaxy plotted within the
Again, while in the area and since it had been quite a while that I’d last visited this nice galaxy; I decided to swing by for a quick look. Still on chart 81-left, I swept about 8.5° southeast from the previous field, I quickly located this behemoth next to a triangle of three stars (two of 7th and one of 5th mag). With 94x it presented a very large and bright diaphanous glow that was slightly out of round. Its disk was very diffuse in nature and unevenly illuminated across its face. The core was extremely bright and concentrated within the galaxy’s structure. Dropping in the 13mm (152x), the galaxy was huge in the field and dappled with variations of light and dark as the eye moved over its disk. In a few minutes I could begin to discern the presence of spiral structure as I could discern the transition from the central bar out to where the spiral arms wrapped around, separated by the dark lanes in between. This sensation was not blatantly obvious, but very subtle and ghostly, as if a veil were between me and the galaxy to make the appearance more elusive. All in all, this made for a very beautiful and riveting visual experience.
Over 7.5° SSW of
It was now approaching midnight and time to head back north where the extinction was less and the seeing more stable, before the moon reared its bright head later on. So I now swung up to Leo Minor to rake in some new ones in the little lion. I have observed a few galaxies in this constellation, but that was mostly from our light polluted back yard with the 10 or 12 inch. So I wanted to work on some more of the numerous galaxies that litter this small constellation. I turned the IDSA to chart 34-right and then aimed the scope at 46 Leonis Minoris to begin my foray.
The first of a small grouping of galaxies just west of a wide pair of 7th mag field stars. Observed at 94x to 199x, it presented a slightly small oval that was evenly illuminated across its disk. It was bright and readily apparent in the field. (New)
About 6’ southwest of the previous object and in the same field, I also picked up this small and somewhat bright thinner oval. It too remained homogeneous at 94x to 199x. (New)
Almost 10’ southwest of the last object, and in the same field as the previous pair, I also spotted this lenticular. Like the other two it remained homogeneous at 94x to 199x. It presented a thicker oval that was small in angular extent but somewhat bright to the eye. (New)
This previous observed pair lay about 19.5’ west of the previous three, and together the duo are catalogued as ARP 270. At 94x I could see there were two distinct ovals nearly in contact. The two disks formed a right angle and were similar in apparent brightness. Both remained homogeneous even at 199x. They formed a nice pair and something I haven’t observed in about eight years. Somehow I had overlooked the triplet to their east however.
Moving back to 46 LMi, I found this galaxy just over 1° to its northwest. At 94x it presented a small and round slightly bright orb. Looking with 152x it remained small but its center now exhibited a broader brightness within the overall halo. Then at 199x it was quite obvious in the field and somewhat bright, and though small its core still showed a prominent broad brightness. (New)
Nudging nearly 3° northwest in the direction of 38 LMi (mag 5.8), I located a small boxy grouping of stars and this galaxy at its northwest corner. Found with 94x it was a small and round slightly dim mote displaying an intermittent stellar core. Also observed with 152x and 199x, its stellar core was more obvious and the galaxy disk was more apparent as well. (New)
Shifting south again, I located first 42 then 43 LMi (mag 5.4 and 6.2 respectively. Then 50’ SSW of 43 LMi I found this barred spiral. With 94x I found it slightly bright and small. Rounded in shape, it displayed a non-stellar concentrated core brightness. Also observed with 152x and 199x, it was an obvious presence in the field, small and round, exhibiting a broadly brighter core. (New)
Just over 4° WNW of the previous object, just south of mag 6.6 HD 90717 I pulled down this nearly edge-on barred spiral. At 94x it was small, but somewhat bright. A thin sliver, it was slightly thicker in the minor axis at the core indicating a central bulge. The core itself exhibited a broadly brighter presence. Viewed with 152x it was very obvious and thin, still showing a very strong broad brightness within its core area. (New)
I next nudged to the northwest about 3° 45’ to the
By going to Leo Minor I was killing some time waiting for
WBL-368 (Leo-
My swan song for the evening would be another of the WBL galaxy clusters. This one straddles the Leo-
Also catalogued as
About 9’ southeast of the previous object, it was picked up at 94x as a small and dim round homogenous glow. When I moved up to 152x its core became stellar in appearance and even though it remained dim at 199x, it was still obvious within the field. This galaxy also has a mag 14.8 companion, PGC 37703, and the pair are designated ARP 138. However, this weaker partner was not seen. Within the cluster,
A touch over 5’ northeast of the last object I spotted this fairly dim rounded glow using 94x. Viewed with 152x and 199x it remained evenly illuminated across its disk, and easily seen within the field. Its cluster designation is WBL 368-013. (New)
Moving back across into Leo about 11’ northwest of
Next in line was this spiral, known as WBL 368-003 within the cluster. Like the previous object it was thin and homogeneous when viewed at 152x to 283x. It was obviously dimmer than
The last one of the trio was this dim oval. Small in size, it was thicker in minor axis than the previous object. It was positioned between a pair of 12th magnitude field stars, which had no impact on its visibility. It remained a dim homogeneous oval at 199x and 283x, though again, not difficult. Its cluster designation is WBL 368-004. (New)
And thus it ended, just past 0130 hours. I was starting to have some difficulty in picking up some of the galaxies in the brightening sky, plus my own tiredness was starting to impair my concentration. So that told me the better part of valor was to call it a night. But it was an interesting session, with some of the old, as well as some of the new. I enjoyed taking a look at some old friends with the big scope. Their visual presentation changes as