Welcome to the exciting conclusion to the deep sky objects of Delphinus, as seen through the eyepiece of a 12" reflector. Well, maybe not exactly exciting. Delphinus does not have a big showpiece object, but there are a few minor treasures. Here is one of them...
gc 6934 (7'.1; V. mag. 8.9; Br. * 13.8) was located at 60x, in a line of four bright stars. The first night I observed this object, it was just getting quite damp. 100x resolved a very few stars, and the globular cluster was very granular. 187x began to give fair resolution of the outer haze. The now stellar core is very bright, with a massive amount of less bright haze surrounding it. Lastly, a large area of even fainter haze surrounded all. Having said that, the cluster is compact and tight, not easily giving up its stars. More resolution comes at 200x, and the core still blazes with brightness. I observed it again the following night, which was much drier. It was now quite magnificent! Stars resolved to the core, and up to 250x was used to very good effect, showing many more stars than last night. A decent object in a 12" mirror.
eg 6944 (1'.5 x 0'.6: V. 13.8; SB 13.4) was an easy object to view at 125x, even though it lies close to a bright star. It is pretty large, elongated strongly NE to SW, and 187x shows a bright, stellar core. More difficult is its nearby partner, eg 6944A (0'.9 x 0'.7: V. 14.1; SB 13.5). It was very elusive, even on a fine night. Like its parent, it lies close to a bright star (even closer, in fact). Only the core area is glimpsed with averted vision at 187x, so look for something much smaller than its stated dimensions.
eg 6988 (0'.5 x 0'.5: V. 14.6; SB 13) is very faint, small and round. This elusive object was seen with averted vision at 200x. I also used a pinpoint hand-drawn chart to locate it (see my recent entry on using strategy to find faint galaxies).
pn 6891 (21"; V. mag. 10.5; Cent. * 12.4 mag.) is small, but easily located at 60x. It was then confirmed at 120x with a Skyglow filter. At 250x the object is very bright and bold, the central star being surrounded by a bluish-grey haze. Two faint stars precede it, and another follows.
pn 6905 (72"; V. 11.1; Cent. * 15.7 (?)) was located at 60x, nestled in a loose, bright field of stars. At 187x the central star appeared. There is wispy detail in the nebula, too. It was seen best with no filter. Up to 375x was used tonight with success. This is an unusual and recommended object, due to its large size and apparent brightness. I question the given central star mag., as it was even seen back in the day with my Edmund 8". Perhaps mag 13.7??
oc 6950 (14'; 60 *s) was swept up at 60x, being a large, loose group. However, it does have a somewhat dense center. Fully resolved at 100x, it is a bright and cheerful-looking group of stars. There is superb sweeping in the immediate area. It is easy to hop to Alpha from here, and the rest of the dolphin shape. At 43x (2" eyepiece) it is a noteworthy cluster, recommended for 8" or higher. It is the only NGC open cluster in Delphinus.
eg 7003 (1'.1 x 0'.8: V. 13; SB 12.7) was located at 60x, at the south preceding end of a string of four bright stars. Confirmed at 100x, using up to 200x shows a large, oval patch of faint haze. A faint star is following the object; another one is south. This is one of the less dim galaxies of Delphinus. A good 8" scope should find it.
gc 7006 (3'.6; V. 10.6; B * 15.6 mag.) was located at 60x. It was pretty large, round and ghostly, reminding me of a giant planetary nebula. Up to 250x was applied, but no stars resolved. It was still pretty bright, though. Two very faint stars are south.
oc French 1 (13'; Br * 8.8 mag.) provides a nice little surprise, being a bright, large cluster observed at 60x and 100x. There are about 25 stars, half of which are very bright and white. Four stars are plotted within its boundary on Uranometria Chart 83. This is a pleasant stop, and it was also observed successfully in the 6" reflector. It is easy to find with a push-to computer, as it is adjacent to eg 7025 (see below).
eg 7025 (1'.9 x 1'.3: V. 12.8; SB 13.6) is not difficult to find. A mag. 9.7 star is on the west edge of the galaxy, within oc French 1 (see above). Spotted easily at 100x, it also looked fine with the aperture stopped down to 8". In fact, we managed to glimpse it in Deb's 6" scope at 125x, once we knew where to look! It was an exceptionally fine night. The galaxy was oval and pretty bright, and had a bright center. Despite the attached bright star, it is an easy object.
eg I. 1359 (1'.2 x 0'.4: V. 13.9; SB 12.9) was located at 100x and confirmed at 125x. It was a long, thin slash following two faint stars. The view improves at 150x and 187x, but the oject is very faint at 200x.
Last, and certainly least, I returned to the area of eg 6927 to hunt down its tiny, very faint companion eg 6927A (0'.4 x 0'.2: V. 15.5; SB 11.8). This one is tricky, and for experienced observers only! Using a hand-drawn pinpoint map to help me identify it, this tiny, faint object was seen with averted vision at 200x, just south of 6927 (see previous blog entry). While here I also reviewed 6927 (not that difficult tonight), 6928 and 6930 (always difficult). All four galaxies were seen at 200x.
This concludes deep sky studies of Delphinus with my Orion 12" Dob. Next up is a brief look at Sagitta.
Mapman Mike
eg 6944 (1'.5 x 0'.6: V. 13.8; SB 13.4) was an easy object to view at 125x, even though it lies close to a bright star. It is pretty large, elongated strongly NE to SW, and 187x shows a bright, stellar core. More difficult is its nearby partner, eg 6944A (0'.9 x 0'.7: V. 14.1; SB 13.5). It was very elusive, even on a fine night. Like its parent, it lies close to a bright star (even closer, in fact). Only the core area is glimpsed with averted vision at 187x, so look for something much smaller than its stated dimensions.
eg 6988 (0'.5 x 0'.5: V. 14.6; SB 13) is very faint, small and round. This elusive object was seen with averted vision at 200x. I also used a pinpoint hand-drawn chart to locate it (see my recent entry on using strategy to find faint galaxies).
pn 6891 (21"; V. mag. 10.5; Cent. * 12.4 mag.) is small, but easily located at 60x. It was then confirmed at 120x with a Skyglow filter. At 250x the object is very bright and bold, the central star being surrounded by a bluish-grey haze. Two faint stars precede it, and another follows.
pn 6905 (72"; V. 11.1; Cent. * 15.7 (?)) was located at 60x, nestled in a loose, bright field of stars. At 187x the central star appeared. There is wispy detail in the nebula, too. It was seen best with no filter. Up to 375x was used tonight with success. This is an unusual and recommended object, due to its large size and apparent brightness. I question the given central star mag., as it was even seen back in the day with my Edmund 8". Perhaps mag 13.7??
oc 6950 (14'; 60 *s) was swept up at 60x, being a large, loose group. However, it does have a somewhat dense center. Fully resolved at 100x, it is a bright and cheerful-looking group of stars. There is superb sweeping in the immediate area. It is easy to hop to Alpha from here, and the rest of the dolphin shape. At 43x (2" eyepiece) it is a noteworthy cluster, recommended for 8" or higher. It is the only NGC open cluster in Delphinus.
eg 7003 (1'.1 x 0'.8: V. 13; SB 12.7) was located at 60x, at the south preceding end of a string of four bright stars. Confirmed at 100x, using up to 200x shows a large, oval patch of faint haze. A faint star is following the object; another one is south. This is one of the less dim galaxies of Delphinus. A good 8" scope should find it.
gc 7006 (3'.6; V. 10.6; B * 15.6 mag.) was located at 60x. It was pretty large, round and ghostly, reminding me of a giant planetary nebula. Up to 250x was applied, but no stars resolved. It was still pretty bright, though. Two very faint stars are south.
oc French 1 (13'; Br * 8.8 mag.) provides a nice little surprise, being a bright, large cluster observed at 60x and 100x. There are about 25 stars, half of which are very bright and white. Four stars are plotted within its boundary on Uranometria Chart 83. This is a pleasant stop, and it was also observed successfully in the 6" reflector. It is easy to find with a push-to computer, as it is adjacent to eg 7025 (see below).
eg 7025 (1'.9 x 1'.3: V. 12.8; SB 13.6) is not difficult to find. A mag. 9.7 star is on the west edge of the galaxy, within oc French 1 (see above). Spotted easily at 100x, it also looked fine with the aperture stopped down to 8". In fact, we managed to glimpse it in Deb's 6" scope at 125x, once we knew where to look! It was an exceptionally fine night. The galaxy was oval and pretty bright, and had a bright center. Despite the attached bright star, it is an easy object.
eg I. 1359 (1'.2 x 0'.4: V. 13.9; SB 12.9) was located at 100x and confirmed at 125x. It was a long, thin slash following two faint stars. The view improves at 150x and 187x, but the oject is very faint at 200x.
Last, and certainly least, I returned to the area of eg 6927 to hunt down its tiny, very faint companion eg 6927A (0'.4 x 0'.2: V. 15.5; SB 11.8). This one is tricky, and for experienced observers only! Using a hand-drawn pinpoint map to help me identify it, this tiny, faint object was seen with averted vision at 200x, just south of 6927 (see previous blog entry). While here I also reviewed 6927 (not that difficult tonight), 6928 and 6930 (always difficult). All four galaxies were seen at 200x.
This concludes deep sky studies of Delphinus with my Orion 12" Dob. Next up is a brief look at Sagitta.
Mapman Mike
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