by Steve Gottlieb
The last time I observed at Lake Sonoma (Tuesday, 8/17) I focused on Cepheus and since NGC 6946 is currently hosting a relatively bright supernova I decided to hang around again in Cepheus where there's a nice mix of open cluster, planetaries, emission nebulae and even some galaxies. The breeze and soft seeing later on kept observations at under 220x, though Matt ventured a bit higher on occasion with his C-8. With several objects we compared views in my 18-inch Starmaster with his 8-inch and he successfully pulled in several faint objects including Sharpless 2-157 and Cederblad 214.
Here's a mix of some eye-candy and fainter stuff in Cepheus which I took a look at (along with older observations).
| NGC 6939 = Cr 423 = Mel 231 = Lund 960 | 20 31 30 +60 39.7 | V = 7.8; Size 8 |
|---|---|---|
| 18" (10/9/04): beautifully rich cluster of ~150 star in a 10'-12'
triangular region over haze. Beyond the ends of the triangular
vertices are four 10th magnitude stars with the star towards the ENE an
easy double. The cluster is fairly uniform with a rich clump of a
half-dozen stars near the center. A number of the stars are in chains,
including a string of equally spaced 12-13th magnitude stars along the
south side which is oriented NW-SE. N6946 (which was sporting a
supernova) lies 40' SE and both can be placed in the same low power
field.
18" (8/17/04): this triangular-shaped rich cluster is beautifully framed in the 160x field (24'). The cluster is enclosed within a kite asterism of four mag 10 stars with two of these stars near the east and west vertices of the triangular outline. ~125 stars are visible in a 10' diameter, with most of the stars mag 12-14. Just west of center is a very rich 3' group and just following this group is a small knot of 4 very faint stars. The west side is well-defined by a string of mag 12 stars oriented NW-SE. 17.5" (9/14/85): about 100-140 stars mag 12-15 are resolved. Difficult to count as stars fill the 22' field at 220x with no distinct boundaries. N6946 is located less than 40' SE. 13" (7/27/84): ~80 stars resolved but richness makes an accurate count difficult. 13" (7/5/83): ~70 stars resolved at 166x, very rich, beautiful in faint stars. | ||
| NGC 6946 = UGC 11597 = MCG +10-29-006 = CGCG 304-006 = Arp 29 | 20 34 52.3 +60 09 14 | V = 08.8; Size 11.5x9.8; SB = 13.8 |
| 18" (10/9/04): viewed type II supernova 2004e, discovered 9/27/04 (13
days ago) which still appears mag 13 or slightly brighter. Easily
identified using a photographic finder chart. The supernova is located
4.1' E and 1.9' S of the nucleus, just west of a pair of mag 13/13.5
stars at 12" separation and was comparable to the brighter star of this
pair. A fainter mag 14.4 star is close WSW and the three stars plus
supernova form a small wedge of Sagitta shaped group. This is the 8th
supernova discovered in N6946 since 1917.
17.5" (8/29/92): bright, very large, 6' diameter to main body, elongated 3:2 ~E-W. Three arms are visible. A long bright arm is attached at the north side of the core and trails to the east. This eastern arm splits; a short fainter branch bends south following the core and a long curving bright arm terminates with a very faint, very small HII knot. On the west side a fainter arm shoots sharply to the north from the core. These outer arms significantly increase the diameter of the main body. The galaxy has a very large brighter middle but the core is just a very small brighter region close SW of the geometric center. A very faint stellar nucleus was seen with direct vision. Observation from 12,000' in the White Mountains. 17.5" (8/13/88): main spiral arm very prominent and easily seen to split. 17.5" (9/14/85): bright, large, brighter central core. A prominent arm attached on the NE side of the core and trailing to the east. This arms splits - the shorter arm is close to the core and a brighter region or arm to the west. 13" (7/27/84): bright arm on the east side highly suspected to branch or split into two arms. Also an arm or brigter region seen on the opposite side of the galaxy pointing W a short way. | ||
| NGC 7076 = PK 101+8.1 = Abell 75 = PN G101.8+08.7 | 21 26 23.6 +62 53 33 | V = 14.5; Size 67"x47" |
| 18" (10/9/04): picked up at 73x (31 Nagler) as a fairly small, fairly
faint disc, perhaps 35"-40" in diameter (fairly small to be in the
Abell catalogue). Appears evenly illuminated at low power. Viewed
unfiltered at 160x and a couple of faint stars are embedded, one at the
east edge and one at the north. Only a weak contrast gain using the
OIII filter and easier to view unfiltered at 225x. At this power the
shape appears irregular and brighter along the east side. Neither of
the two stars appear to be the central as they're situated at the edge
of the halo. A number of 13-15th magnitude stars are in the field
including a couple of 14th mag stars 1' and 2' N and a small, fainter
trio close west. Located 56' ENE of mag 2.5 Alpha Cephei (Alderamin).
17.5" (7/5/86): fairly faint at 79x using an OIII filter, slightly elongated, moderately large, estimate V = 13.5-13.8. Faintly visible unfiltered. At 222x two stars are superimposed; a faint star near the center (central star?) and one at the north edge. On line with two mag 14 stars 1' N and 2' N. Located 15' SE of mag 7.2 SAO 19386. Identified as Abell 75 in CGPN and ESO-Strausberg catalogues. This object was first recorded by WH as III 936. His position was 7 min 54 sec following Alpha Cephei and 16' north. This places it at 21 26.5 +62 51 (2000). Just 2' N of this position is the planetary Abell 75 which was rediscovered by Abell but not associated with the NGC number. The ESO-Strausberg planetary catalogue also uses the Abell designation. RNGC lists N7076 as a diffuse nebula instead of a planetary and furthermore the declination is 6' too far S. The ESO-Strausberg catalogue gives a precise 2000 position 21 26 24.1 +62 53 27. I discovered the equivalency N7076 = Abell 75 and listed it in the 3rd RNGC Corrections list. | ||
| NGC 7094 = PK 66-28.1 = PN G066.7-28.2 = K 1-19 | 21 36 52.9 +12 47 19 | V = 13.7; Size 99"x91" |
| 18" (10/9/04): picked up at 73x using the OIII filter as a fairly
faint, round, evenly lit 90" disc. Good contrast gain with the filter.
Faintly visible unfiltered at 160x as a moderately large but low
surface brightness halo surrounding the 13.5 magnitude central star. A
faint mag 14.5 star is atf the NE edge of the halo. A string of 3 mag
14-15 stars is ~2' NE. Images show the a complex multi-rim structure
(brighter along the west side) with a darker center, but visually the
planetary appeared pretty featureless. Located 7' S of a mag 10 star
(SAO 107277).
17.5" (10/2/99): at 100x and OIII filter appears fairly faint, round, moderately large, 1.5' diameter, even glow. At 220x without filter, the central star is easily visible surrounded by a round, low surface brightness glow. A very faint star is at the NE edge. No annularity seen. 13" (6/18/85): at 62x with filter appears faint, moderately large, round. Without a filter the faint mag 13.7 central star is visible surrounded by a very low even surface brightness halo 1.5' in diameter. | ||
| M 2-51 = PK 103+0.1 = PN G103.2+00.6 | 22 16 03.3 +57 28 41 | V = 13.6; Size 47"x38" |
| 18" (10/9/04): at 160x without filter, a 14th magnitude star (not the
true central star) is easily visible surrounded by a very faint haze.
A second faint 15th magntude star is also involved. Adding an OIII
filter, the planetary is quite prominent and appears as a crisp-edged
30" disc, slightly elongated N-S. The superimposed stars are lost in
the fairly high surface brightness haze with the filter.
17.5" (10/30/99): easily picked up at 100x using an OIII filter. Appears fairly bright, round, ~30" diameter. At 220x faintly visible unfiltered and two stars are superimposed oriented SW-NE with the brighter eastern star just following the center of the PN. Responds very well to filtration and holds 280x well with a UHC filter. A slight elongation N-S is evident at this power. 17.5" (8/26/89): at 140x just visible unfiltered as a fairly small disc, slightly elongated. Excellent contrast gain with OIII filter and easily held steadily with direct vision. Two mag 13.5/14 stars are superimposed (not the central star). 13" (8/11/85): at 88x with OIII filter appears fairly faint with direct vision, fairly small, slightly elongated. At 166x and UHC filter; faint, moderately large, clearly elongated N-S. Located 16' N of mag 5.9 SAO 34256. | ||
| Be 94 = OCL-231 = Lund 1014 | 22 22 53 +55 52.2 | V = 8.7; Size 4 |
| 18" (10/9/04): located 6' SSW of a bright orange star (mag 6.4-7.6 red supergiant RW Cephei) is a small, fairly distinctive group of a dozen stars within 2' at 160x including three mag 10 stars (one actually lies 1.5' north of the cluster). At 225x, roughly 20 stars are resolved including a dense 40" knot of stars surrounding the 10th magnitude star at the center. | ||
| IC 1454 = PK 117+18.1 = Abell 81 = PN G117.5+18.9 | 22 42 25.0 +80 26 32 | V = 14.4; Size 34"x31" |
| 18" (10/9/04): easily picked up at 73x just 4' WNW of a 7th magnitude
star as a small, well-defined disc. Visible unfiltered at 160x and a
couple of mag 14/15 stars are barely off the NE edge of the planetary
and a 13th magnitude star lies 1' SE. Good contrast gain with OIII
filter. The disc is perfectly round, ~25" diameter with a very crisp
edge. The surface brightness appeared a bit irregular but could not
verify annularity at this power.
17.5" (10/13/01): picked up at 100x without filter as a faint, small disc situated 4' WNW of a mag 7 star. Excellent contrast gain with an OIII filter and appears as a round, 25" crisp-edged disc. At 220x without filter a faint mag 14/15 pair is at the NE edge. Very nice view using a UHC filter at 140x-220x; the PN is slightly elongated ~E-W but no other details are visible. 17.5" (8/8/91): moderately bright, fairly small, almost round, slightly elongated E-W, 30" diameter. A faint double star mag 14/15 is at the NE edge. Located 3.8' WNW of mag 7 SAO 3785. No central star visible. Pretty planetary at 220x without filter. 13" (8/11/85): at 88x and OIII filter, fairly faint, fairly small, round. Located 4' W of a mag 7 star which detracts from viewing. At 166x with a UHC filter; easy to view, moderately large. Two very faint stars are involved near the NE edge. | ||
| King 10 = OCL-248 = Lund 1025 | 22 55 00 +59 09.9 | Size 3 |
| 18" (10/9/04): this small, rich group is beautifully framed in the 73x (31 Nagler) field as it is sandwiched between a group of half-dozen bright stars to the NW including a collinear, equally spaced trio oriented E-W and chain of stars that trails to the east to group of 4 mag 8-9 stars forming a square (sides 10'-12' oriented N-S and E-W) with a 5th 9th magnitude star at the geometric center! At low power the cluster appears as a rich dusting of faint stars, though only 10 or so are resolved over haze. At 220x, two dozen stars are resolved over haze in a 3' group. Includes a few mag 12 stars, but most are mag 13-15 and appear to be situated along 3 sides of the periphery of the cluster. | ||
| NGC 7510 = Cr 454 = Lund 1030 = OCL-256 | 23 11 04 +60 34.3 | V = 7.9; Size 4 |
| 18" (10/9/04): beautifully rich, small cluster with a triangular or
wedge-shaded outlilne. Roughly 50 stars are resolved in a 4'x2' region
with additional sprays of stars extending to the SW and NE. There is a
well-defined border of brighter stars running SW-NE along the south
side of the wedge with the brightest mag 9.6 member at the east end of
this string. There are several 11-12th mag members, but most seem mag
13 and fainter. The north end of the giant HII complex, Sh 2-157, lies
~30' E.
17.5" (10/17/98): very pretty triangular wedge of stars in a 5x2' group. There are brighter stars at the W and E vertex with the brightest star at the following end. Within the triangle are two dozen stars oriented SW-NE including a number of mag 14-15 stars on the eastern side. Just following the main grouping are another 8 or 9 stars which may be part of the cluster. Picked up while viewing nearby Sh2-157. 13" (9/9/83): striking at 62x, about two dozen stars in a wedge-shape elongated SW-NE. Compact cluster Mrk 50 and HII region LBN 11 is ~30' ESE. | ||
| M 2-55 = PK 116+8.1 = PN G116.2+08.5 | 23 31 52.7 +70 22 10 | V = 14.4; Size 42"x36" |
| 18" (10/9/04): easily picked up at 73x while sweeping with an OIII
filter as a small, compact disc. Excellent view at 160x using an OIII
filter. Appears as a sharply defined, fairly faint disc, 30"-35"
diameter. The surface brightness is slightly irregular, but no
definite annularity was visible. Easily visible with direct vision and
fairly prominent for a Minkowski planetary. A mag 11 star lies 2' NNE
and a similar star is 1.2' ESE.
13.1" (8/17/85): 79x and OIII filter; fairly faint, fairly small, round disc. Very faint but also visible unfiltered. A mag 11.5 star is off the E edge 1.2' from the center. Located 8.3' W of mag 8.6 SAO 10779 and 6.3' WSW of mag 9.2 SAO 10777. | ||
Posted on sf-bay-tac Oct 10, 2004 12:40:04 PT
Converted by report.pm 1.2 Jan 14, 2005 19:27:18 PT