October 25, 2011 Observing Report – Sun Pollution

In between travel and other obligations, the remaining windows of opportunity to visit Zephyr Ridge Observatory this fall were thwarted by bad weather.  But, finally, I was able to make a trip there from October 24-26 when the forecast was favorable.

Indeed, the sky was clear and everything seemed set for a nice couple of evenings exploring the late autumn and early winter sky.  On the first night, I decided to take a nap after dinner and begin observing after midnight and continue until dawn.  Over the years I have been gradually observing the so-called Herschel 400, and I had only 15 objects remaining on the list, and these would be visible during the two hours preceding morning astronomical twilight.

As I prepared my telescope around 1 AM on October 25, I examined the night sky and noticed that the stars did not seem to “pop” like they usually do, and the Milky Way seemed a little muted.  Everything was there, the sky seemed otherwise quite clear, but it just did not look as dark and transparent as I normally experience.  I took measurements with my Unihedron Sky Quality Meter and obtained values of around 21.00 mag/arcsec2, which is quite a bit lower than the 21.50+ readings I get on the better nights at Zephyr Ridge Observatory.

The first suspect in such instances is atmospheric moisture or high clouds.  I cannot discount this entirely, but it seemed unlikely given the weather conditions and my experience there.  How about smoke from a large forest fire?  I knew of nothing happening during that time, although there was a forest fire two months earlier some 30 miles away; surely smoke from this fire had long dissipated.  I certainly did not smell smoke, and there was one night two years ago in which I did smell smoke from such a fire, and still had a better sky than what I saw on this night.

The less transparent sky persisted throughout my two-night stay.  I observed from 1 AM until dawn on the first night, and from dusk until around 9:30 PM on the second night.  I quit rather early on the second night due to fatigue and the fact that the sky was just not dark enough to pursue some of the faint galaxy clusters I had intended to observe.

When I returned home I did some investigation and discovered that on the very day (10/24/11) of my arrival at Zephyr Ridge Observatory the earth was hit by a coronal mass ejection of the Sun, which caused aurora that were visible throughout the United States, even in areas that rarely experience such displays.  I had no idea about this while I was at the observatory, and I rarely spend time looking to the north, as my roof obstructs most of the northern sky.  I think I experienced the negative effects of the aurora on deep sky observing, without thinking to try to enjoy the opportunity of observing the aurora itself!

It seems I need to monitor both earth and space weather in planning future trips to Zephyr Ridge Observatory.

I provide my observations below.  One object of particular interest, which I failed to see, is one that may be unfamiliar to most readers:  Gyulbudaghian’s Nebula.  This is a so-called variable nebula whose brightness varies with the brightness of the variable star (PV Cep) that illuminates the nebula.  It is a fascinating object, and this was my first attempt to see it.  As I remark below, not only did I not see Gyulbudaghian’s Nebula, but I also failed to see PV Cep itself, even though I was quite sure I was looking in the correct location.  Perhaps my effort was thwarted by the Sun’s hiccup, or perhaps PV Cep is quite dim now, or both.  I have tried to find recent observations online, and have so far been unsuccessful.  If anyone knows more, I would appreciate hearing from you.  I will certainly try this object again some day.



All observations were made with a 20” f/5 reflector, unless otherwise noted.  Due to the low altitude of several objects, I also used a 4” Borg refractor to be able to see above the south wall of the observatory.  As noted in the discussion above, sky transparency was less than optimal for this site.  Seeing was steady.

10/25/2011 1:21 AM
IC5370 Group    Galaxy Cluster  And  Mag 14.9 (brightest member)
RA 00h00m09s  Dec +32°44’19”

I first scanned this group at 212x, but more detail was seen at 363x.  I was able to see all five members of the group.  I keyed off of a small equilateral triangle of stars, and just to the north of this triangle I saw IC5369, appearing as a small fuzzy spot, rather faint.  Further NE from there is IC5370, which was a little brighter and appeared to have a stellar nucleus.  Along the same line to the NE, I found IC5373, which was fainter than IC5370, and also had a stellar nucleus.  Moving to the NW from IC5373, I encountered a widely separated NS pair of stars, and the southernmost star had a tiny fuzzy spot just off the star to the NW, which is IC5372.  Moving north to the other star in the pair, and then NW from there, I saw another very faint galaxy, IC5371.  Overall, this group was quite faint, no doubt made more so by the less dark sky this night.

10/25/2011 1:36 AM
NGC3 Group    Galaxy Cluster  Psc  Mag 13.3 (brightest member)
RA 00h07m17s  Dec +08°18’05”

Quite a difficult group.  At 363x, NGC3 was located just NE of a fairly bright field star.  The galaxy was moderately faint, with an elongated halo.  Slewing to the NW, I encountered a very faint hazy spot that was located where NGC7837 and NGC7838 are located in close proximity.  I could not distinguish two separate galaxies, but only saw a single hazy glow.  From there, I slewed roughly WNW and found NGC7834, which appeared as a tiny, elusive hazy spot just east of a field star.  I was unable to see any other members of the group.  I think this observation was affected a little by the presence of nearby Jupiter.

10/25/2011 3:26 AM
NGC2311    Open Cluster  Mon  Mag 9.6
RA 06h57m48s  Dec -04°35’00”  Size 6’

Confirmed location with Voyager map.  There is an arc of three bright stars ENE of the cluster that offers a useful finding reference for this cluster.  At 98x this cluster was of moderate size and sparsely populated.  I performed a rough count of the members, and could see about 20 stars with direct vision, and averted vision resolved a few more and gave a hint of added density.  The overall shape of the cluster was a sort of an irregular rectangle.

10/25/2011 3:33 AM
NGC2335    Open Cluster  Mon  Mag 7.2
RA 07h06m36s  Dec -10°05’00”  Size 12’

At 98x this cluster seemed to be a close cousin to NGC2311, observed just before, as it was about the same size and similarly populated.  It is located directly west of a rather bright field star, and there is clump of field stars to the SSW of the cluster (perhaps illuminating the Seagull Nebula, which I forgot to examine).  The shape was an irregular loose oval.  I counted about 30 members resolved directly, and averted vision picked up a few more.

10/25/2011 3:39 AM
NGC2353    Open Cluster  Mon  Mag 7.1
RA 07h14m36s  Dec -10°18’00”  Size 20’

At 98x this cluster was larger than the previous two Monoceros clusters just observed, and also more populated.  The lucida is a very bright star (perhaps not an official member) that sits just south of the center of the cluster.  The cluster is irregularly organized, as there are gaps between areas of dense population.  Just east of the lucida is an apparent double star with equally bright components.  There is another nearby star pair just north of the first double, also with equally bright components.  A nice, bright, well-populated cluster.

10/25/2011 4:02 AM
NGC2354    Open Cluster  CMa  Mag 6.5
RA 07h14m18s  Dec -25°44’00”  Size 20’

This was an extremely low altitude view, about 13 degrees, and I switched to the 4” Borg refractor to get above the south wall of my observatory.  I was able to find the precise location of the cluster using a map and keying off of some bright nearby field stars.  I obtained a somewhat dim view of the cluster, which was rather large.  I could resolve about 25 members with direct vision, and averted vision gave a hint of additional richness but did not seem to add to the count.  The stars that I could resolve were arranged in an elongated pattern.

10/25/2011 4:17 AM
NGC2421    Open Cluster  Pup  Mag 8.3
RA 07h36m18s  Dec -20°37’00”  Size 10’

I first viewed this with my Borg refractor at 53x, and it appeared as a small fuzzy patch, and averted vision showed additional richness.  But, I was able to get at least a portion of the Obsession’s mirror above the south wall to get a better view at 98x.  It appeared as a compact, moderate-sized cluster with roughly 50 resolved stars.  There was no particular shape to the star mass, as the boundary appeared irregular.

10/25/2011 4:26 AM
NGC2440    Planetary Nebula  Pup  Mag 9.4
RA 07h41m55s  Dec -18°12’33”  Size 1.2’x0.7’

At 98x this Planetary Nebula was obviously nonstellar.  Although this observation was made at about 14 degrees altitude, I was able to get a reasonable view at 363x as the seeing was quite steady by now.   This is a lovely object.  It is moderately sized, with a bluish tint.  I could not see the central star, but the center of the nebula was very bright and condensed and yielded to a fainter and elongated halo.  The axis of elongation was approximately SW-NE.  I tried an OIII filter, but it did not improve the view.

10/25/2011 4:34 AM
NGC2479    Open Cluster  Pup  Mag 9.6’
RA 07h55m06s  Dec -17°43’00”  Size 7’

At 98x, this was a large, circular cluster with about 60 members resolved.  All members seemed of comparable brightness.  There is an attractive apparent double star SW of the cluster, with components of equal brightness, and the axis connecting the stars points in the direction of the cluster.  Nice.

10/25/2011 4:42 AM
NGC2482    Open Cluster  Pup  Mag 7.3
RA 07h54m54s  Dec -24°18’00”  Size 12’

Another low altitude view (about 14 degrees) and probably 50% of my mirror was obstructed.  At 98x, this is another large grouping of stars located SSW of a conspicuous triangle of bright field stars.  The cluster had a clumpy character, with a well-populated arc of stars sitting near the center of the mass.  The arc seemed to extend roughly N-S.  I could see about 40-50 members of the cluster, and averted vision hinted at greater richness.

10/25/2011 4:47 AM
NGC2489    Open Cluster  Pup  Mag 7.9
RA 07h56m12s  Dec -30°04’00”  Size 8’

Extremely low altitude view (about 9 degrees), and so I used the Borg refractor to get above (barely) the south wall.  The cluster is located north of a prominent E-W arc of three bright stars.  At this altitude and aperture, the cluster only appeared as a very faint fuzzy patch, best seen with averted vision.  With patience, I was able see that the haze was granular and I could resolve a handful of stars.

10/25/2011 4:55 AM
NGC2509    Open Cluster  Pup  Mag 9.3
RA 08h00m42s  Dec-19°04’00”  Size 8’

An enticing cluster.  I spotted it at 98x, but increased the power to 212x due to its small size.  The cluster’s appearance was interesting.  There is a compact rectangular mass of roughly 30 stars, and just south of this mass there is an A-shaped arrangement of stars that suggests a hat (or roof) on top of the mass.  So, overall, the cluster gave the impression of a house or perhaps a squat Christmas tree.  In total I could resolve about 50-60 stars.  Nice.

10/25/2011 5:03 AM
NGC2527    Open Cluster  Pup  Mag 6.5
RA 08h05m18s  Dec -28°10’00”  Size 22’

At 12 degrees altitude, requiring use of the Borg refractor.  This cluster was not difficult to find, and at 53x it appeared as a rectangular mass of some 20 stars.  Rather sparsely populated, and averted vision only picked up a few more members.

10/25/2011 5:29 AM
NGC2567    Open Cluster  Pup  Mag 7.4
RA 08h18m36s  Dec -30°38’00”  Size 10’

Observed at 10 degrees altitude with Borg refractor (53x).  I had a little difficulty locating this at first, but eventually zeroed-in and confirmed with my map.  It is a small cluster and seemed a little elongated.  I was only able to resolve a handful of stars, but additional richness was suggested with averted vision.  Otherwise, there was not much to see with small aperture at such a low altitude.

10/25/2011 5:35 AM
NGC2571    Open Cluster  Pup  Mag 7
RA 08h18m54s  Dec -29°44’00”  Size 13’

Observed at about 11 degrees altitude with the Borg refractor (53x).  This is another small cluster, similar in size to the previous one (NGC2567).  I spotted the cluster just SE of a conspicuous arc of reasonably bright field stars.  The cluster is small, with three prominent stars within, two of which were quite bright and formed a nice pair in the center of the cluster.  Altogether I could only resolve a handful of stars, and averted vision did not significantly alter this total.

10/25/2011 5:40 AM
NGC2613    Galaxy  Pyx  Mag 10.4
RA 08h33m23s  Dec -22°58’24”  Size 7.2’x2.1’

Back to the Obsession, but very low in the sky at about 17 degrees altitude.  At 212x, this galaxy is obviously elongated, seemingly an edge-on spiral.  The core was a little brighter than the halo, but overall this galaxy was not as bright as I expected, possibly due to the low altitude and the auroral brightening of my sky.  There are several nearby field stars on either side of the long axis in close proximity.

10/25/2011 5:46 AM
NGC2627    Open Cluster  Pyx  Mag 8.4
RA 08h37m18s  Dec -29°57’00”  Size 11’

Back to the Borg refractor (53x) for this 10 degrees altitude view.  I found this cluster to the SW of three bright stars forming an isosceles triangle, the brightest being Zeta Pixidis (magnitude 4.88).  The cluster appeared as a moderate-sized hazy glow that was unresolved with direct vision.  Averted vision allowed me to resolve a few stars, but otherwise the cluster was just a misty glow.

10/25/2011 8:10 PM
HH215/GM 1-29  Gyulbudaghian’s Nebula Variable Nebula  Cep
RA 20h45m54s  Dec +67°57’39”

This is a failed attempt to see this variable nebula.  I was unable to see this nebula at all.  In fact, I was unable to see PV Cephei, which illuminates this nebula.  I tried different eyepieces and even a UHC filter, but no luck.  The AAVSO chart for PV Cep gives a minimum of magnitude 18, so it is quite possible that it was very faint.

10/25/2011 8:27 PM
Abell2666         Galaxy Cluster  Peg  Mag 13.8 (brightest member)
RA 23h50m56s  Dec +27°09’41”  Size 68.3’

A difficult group, especially with a less than optimal sky.  I surveyed the group at 212x.   The brightest member was NGC7768, which was just a small hazy glow, with some prominent field stars to the E and SE.  Just south from there, I could see a tiny fuzzy point which my map shows as NGC7767.  That was all I could see in this region of the cluster.  I panned around looking for other members, and to the SW of the NGC7768/7767 duo, I was able to see UGC12792, which was visible with averted vision as a very faint glow.  Slewing to the NNW, I also was able to see UGC12785, which was visible with direct vision and had an elongated halo.  Also, I picked up one additional galaxy just to the NW of UGC12785, which was just north of a small 4-star keystone asterism.  This galaxy is PGC72438, which I could only see with averted vision as a fuzzy point of light.

10/25/2011 8:51 PM
NGC7619 Group (Pegasus I)    Galaxy Cluster  Peg Mag 11.1 (brightest member)
RA 23h20m15s  Dec +08°12’23”

I toured this group at 212x.  I began with NGC7631, which is east of the main galaxies and just SE of a small equilateral triangle star asterism.  NGC7631 was visible with direct vision, but faint, with an elongated halo and a little brighter core.  From there, I slewed westward to the main pair of galaxies in this group.  The easternmost member of the pair, NGC7626, is bright, with a prominent core and roughly circular halo.  The western member, NGC7619, also had a bright core and roughly circular halo.  These two galaxies were like twins, although NGC7619 seemed a little brighter.  Just off the halo of NGC7619, to the SSW, I saw a tiny fuzzy spot, which is NGC7617.  From here, I slewed to the north, past a bright field star, until I found NGC7623, which was visible with direct vision as a small hazy glow with a slightly brighter core.  (I could not the nearby NGC7621.)  Moving westward, I encountered NGC7615, which was quite a challenge to see, and appeared as only a small smudge with averted vision.  From there I moved north to NGC7612, which was brighter than NGC7615; NGC7612 had a bright core with a little fuzziness around it.  From there I slewed to the SSE and observed NGC7608, which was a ghostly streak only visible with averted vision.  Moving to the south, I was able to pick up NGC7611, which was located NNW of a very bright field star.  This galaxy had an elongated halo and a stellar nucleus.  My map showed a nearby galaxy to the NW, IC5309, but I did not see it.  Finally, I slewed to the SE from there to view UGC12518 and UGC12522, but neither was visible.  This concluded my tour.

10/25/2011 9:12 PM
NGC7530/7532/7534 Galaxy Trio         Psc         Mags 12.1/13.5/13.5
RA 23h14m12s  Dec -02°46’46”

Observed at 363x.  This was a surprisingly difficult trio, perhaps attesting to the poor transparency this evening.  This trio is located near a fairly bright field star.  All three galaxies were faint.  NGC7530 was difficult, but visible with direct vision as a small pinpoint, and averted vision allowed me to see some haze around the point.  The middle galaxy in the row, NGC7532 was the brightest, and had an elongated halo and a brighter core area.  The last, NGC7534, appeared as an elongated wispy glow right next to a field star.  Quite challenging.

10/25/2011 9:21 PM
NGC7699/7700/7701 Galaxy Trio         Psc  Mags 15.1/13.3/13.7
RA 23h34m27s  Dec -02°54’00”

Observed at 363x.  This was another rather difficult group.  The most southerly member, NGC7701, was a faint, elongated streak, best seen with averted vision.  The middle member, NGC7699, was the most difficult of the three, and was only barely visible by using averted vision and slewing the scope back and forth.  The last one, NGC7700, was the brightest member, visible with direct vision.  It had a bright core, with a slightly elongated halo.

About Denis

I am the owner of Zephyr Ridge Observatory and the writer of this blog. For more information, please click the About link at the top of this page.
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