square on the moon, part 2

I reobserved the marble green square area on the moon again last night.  At low power (71x) it was still distinct from the brighter area but not quite as dark as it was the night before, likely from a change in the light angle (93% illuminated).  Seeing was very good, so I ramped up power to 277x then 553x. The color change making the square was still very apparent, but there was a lot more fine detail to observe too, and I could see the delineation between the color changes was not as sharp as at low power.

Starting from Aristarchus: This crater has a bright wedge shaped ejecta field streaming toward Herodotus; these two craters take a corner off of the square.  The darker area continues to Schiaparelli then takes a nearly right angle turn following Dorsa Burnet to Humason.  The next turn seems to be at Nielsen and then back up to Aristarchus, with Rupes Toscanelli as the divider.

What was very interesting was a ghost crater (or is it called shadow crater?) which was a very old formation filled in with lava which had subsequently been deformed by later, smaller crater impacts.  I could trace the sunken, faint round outline from Schiaparelli to below Montes Agricola and into that field.  I don't find this traced on Rukl.  Careful attention rewards the time and effort spent observing.

After only 40 minutes observing the moon went behind the meridian tree.  I used my 7x35 binoculars for a while and was able to pick out some Messier objects despite the light pollution and nearly full moon: M31, M11, M13.  Also the Coathanger and the lovely star fields of Cassiopeia.  The sky around Delphinus and Sagitta was grainy, faint Milky Way stars wishing to be seen.  New moon is coming up, I will have my chance.

square on the moon

Just in from a very short session, but I want to get it down while it's fresh in my mind.

While observing with the 12.5-inch, using 71x and the moon filter, from 4:00 to 4:30 UT, I noticed a distinct square on the moon, a little foreshortened by the curve of the moon, but it was there.  It was a relatively dark color, marble green.  It was as if there was a piece of square tape on the moon, left for a long time -- while the moon collected dust the part underneath the tape stayed clean -- then someone removed the tape leaving this clean green square on the moon.  It must have been a trick of the light (waxing gibbous, 86% illuminated).

The square started at Aristarchus and went to Schiaparelli; then turned at a right angle to Humason; then another right angle to Krieger, then back up to Aristarchus.  A corner of the square was bitten off by Aristarchus and Herodotus, which were still bright, but everywhere else within this boundary was a marble green, contrasted with the rest of the brighter surface.

I see on Rukl there are wrinkle ridges and mountains along the boundary line (Dorsa Burnet, some unnamed, and Rupes Toscanelli) -- somehow these define the boundary, either a change in elevation, or some blockage of light.  The square area is much more rugged than the surrounding area, suggesting it may night reflect as much light back and so appears darker.

It's a very surprising and unique sight.  I'm in early just to write this down but also because the moon went behind the meridian tree and the marine layer started coming in.  I hope it is clear tomorrow, I'll see whether the feature is still there.

more close doubles in aquila

I tried again last night for more close doubles in Aquila in the 12.5-inch.  These were not plotted in CDSA, being either too close or having too wide a magnitude difference between the pairs.  Seeing was perhaps Pickering 6-7, not really good.  I found some and missed some:

BU 265: Yes!  After quite a while of staring and focussing.  Very faint but resolved B at outer diffraction ring when seeing stills.  Yellow A, bluish B.  [7.37, 9.24; 1.4"; 1698 ly].

STF 2408:  A star resolves but is hazy.  There is an airy disk flashing out in the middle of the haze where B is.  [8.47, 9.38; 2.3"].  I wonder if the haze is due to its faintness, poor seeing, or if there is nebulosity in the area?

D 20: Didn't see AB pair (which is 9.58 1.3") despite the tight airy disk of A; but I do see faint star much further out which should be the C pair [AC 7.22, 10.51; 24.6"].  Very near to a pretty orange carbon star.

I tried another few (KUI 91, HU 72, BU 976) but could not make any of the pairs.  There was a thin fog blowing in from the ocean which interfered with seeing fainter stars.  The moon was getting too low to observe well so I packed it in early at 10:15pm

close doubles in aquila

Clear Sky Clock predicted excellent seeing for last night, so I prepared a list of close doubles in Aquila for the night's observation.  Most were <2" separation and about half of the 25 were plotted on the CSDA, and those were the ones I observed.  Seeing is to be good tonight too, so I am printing finders for those not plotted in the atlas.  I used the 12.5-inch at 553x throughout.  I started at 9pm when seeing was good but not great, yet still had nice airy disks.  By 10pm it was very good and by 10:30pm it was fantastic, but that was when I needed to pack in.  "Wide" in my descriptions refer to the easy by which they were separated.  Some of the C pairings were missed because they weren't on the list, being wider than my cut-off criteria:

STF 2404, well split, yellow A and yellow-orange B.  [6.92, 7.77; 3.6"]

STT 368 AB: Definite split, 1/2 an airy disk width; near equal brightness.  Did not notice AC  [7.53, 8.49; 1.1"]

23 Aql AB: Pretty wide separation, just a large difference in magnitudes.  A bright orange, B bluish. [5.28, 8.29; 3.2]  Faint star much further out was the AC, 13th mag 10".

STF 2545 AB: Easy, wide separation yellow and orange.  [6.79, 8.54; 3.8"].  Did not notice C pairing.

AC 12: [Alvin Clark!]: Pretty wide separation, about 1 magnitude difference.  [7.54, 8.32; 1.5"]

52 / Pi Aql / STF 2583 AB: Very definite split.  A mini Alberio, gold and blue.  [6.34, 6.75; 1.5"]  Did not see AC pair.

STF 2596: Definite clear split, 2 airy disk widths.  (High on the ladder, hanging over to see; drive on the equatorial platform ran out!).  [7.29, 8.68; 2"]

HI 93: Easy, fairly wide separation.  [7.67, 8.39; 1.8"]

Anonymous ~ 2 minutes east of STF 2654: Bright A and faint B, ~2.5" separation.  Very nice.

65, Theta Aql: listed as having an Ab and Ac, with 1" separation, but nothing was seen.  Surely an error, or spectroscopic only -- no magnitude given for the 1" pair.

STF 2644: Nice near equal pair, wide separation.  [6.92, 7.06; 2.5"]

STF 2643: White and reddish stars, wide separation, large magnitude difference.  [8.17, 9.23; 13.8"]

STF 2651 AB: Very close but clear split, equal brightness white stars.  In a rich field.  This wasn't plotted in CDSA so I swept the area to find; I feel the thrill of discovery.  Beautiful sight.  Seeing is very calm.  Great way to end the session.  Too bad I need to go in.  [8.41, 8.44; 1.0"]

impressions

Was out last night with the 12-inch, but mainly wandered and gazed rather than observed.  As a result I have a set of impressions rather than observations:

The Moon:
Far detached peaks at sunrise -- first flash of dawn
The grey round mass of the unlit moon: perfect grey-black sphere, closing in on a star
Mountain ridge looks like a gecko missing its tail
Dark craterlets, sinuous crater rims
Ghost craters in the shallow seas, like ripples on smooth water
Wrinkle ridges, the moon showing its age
Fans of ejecta

Mars: Syrtis Major jutting down like India

Sweeping for doubles in Aquilla:
Faint close triple, same magnitude, a triangle with equal sides
Many faint double pairs
Teal blue pair, equal, about 9th magnitude, 3" separation -- lovely pair of eyes

pinnacles

Sunday night joined Jamie Dillon at the Pinnacles National Park at the Chaparral Trailhead parking lot, beneath the hoodoos.  While driving above Soledad on Route 149 I noticed smoke from the Soberanes fire in the mountains to the west.  The winds from the north / north-northwest blew it away from the Pinnacles.  We had an impromptu star party for some hikers who came to the parking lot after dark – they said they got a little lost on the trails and were relieved to make it back.  After turning off their flashlights they enjoyed the starry sky; two of them lay down on the pavement, to both rest and take in the Milky Way.

Seeing was not great in the beginning of the night, but it got better.  I estimated Pickering 6 by 10pm and 7 after 11pm, and I daresay up to 8 after 1am.  Transparency was merely good; minor dewing persisted through the night.  It was surprisingly cold, low 40s at midnight dipping into the upper 30s very late –along with the rise of the Hyades, it was a herald of the approaching winter.  I should have just taken the best near zenith, but the tyranny of my lists drove me to Sagittarius and environs.  Toward 2:00am Jamie was able to make out the Gengenschein just below and to the east of the Circlet in Pisces.  I could not discern it despite Jamie’s careful description; I have never seen it and didn’t know quite what to see.  Here are some other highlights, all in my 20-inch reflector:

NGC 6620, PN in Sgr, 12.7v, 5.3” x 3.8”: @ 205x a small bright disk, bluish grey unfiltered, more strongly blue-green with OIII.  Soft but consistently round rim; no central star. 

NGC 6629, PN in Sgr, 11.3v, 16” x 14”: @ 205x it appears as a smallish hazy disk with a bright central star.  Has a ragged blue-green outer shell [others report seeing sharp edges, so my view may have been distorted by poor seeing].  Very dense field.

IC 4732, PN in Sgr, 12.1v, 3”: @205x, small and faint somewhat bloated star in line with two other brighter stars.  OIII makes it blink as a PN.  No central star seen.

NGC 6644, PN in Sgr, 10.7v, 2.5”: @205x, small but bright & stellar, blinking with OIII.  Soft edged, bluish disk, no central star.  333x made the disk more apparent but did not give more detail.

IC 4776, PN in Sgr, 10.9v, 8”: @205x, bright and small, bluish, blinking with OIII.  Soft edges and no central star.

NGC 6526, Bright Nebula in Sgr, and part of M8, 40’ size: A real stunner and an easy Telrad find.  @ 121x the M8 complex filled the field; UHC was best filtered view, bringing out much detail.  6526 is the SW portion of M8, and was a bright sweep of nebulosity, providing contrast for the dark nebula dividing it from NGC 6523, the NE portion of M8.  A very bright bow-shaped nebula appeared at the end of three stars near the SW tip of the dark nebula, which I took to be 6526 but which I find out now is the Hourglass Nebula.  Panning around the scene, there was more, fainter nebulosity to the north and east, and many pretty groups of stars.

NGC 6309, PN in Oph, 11.5v, 20”: “Exclamation Point Nebula”: Bizarre looking bright cigar shaped PN elongated 3:1 NNW-SSE with a bright star off the NNW tip, making it appear as an exclamation point.  Used 333x; UHC helped contrast.  The NNW portion of the PN is brighter.  According to Wikipedia it is quadrupolar but I did not resolve the separate portions.

M 2-9, PN in Oph, 13.2v, 60”x30”: “Minkowsky’s Butterfly”.  @ 333x a small, elongated 3 or 4:1 N-S.  It looks rather like a galaxy, overall very faint but with a small brighter round central region with quickly fading and tapering tips.  The center flashes a central star with averted vision and brief moments of good seeing.  Filters don’t seem to help the view.   

NGC 6712, Globular Cluster in Sct, 8.1v, 7.2’:  @ 333x, pretty large and irregularly round, with a couple dozen stars resolved in front of the misty grey core, and more stars sparking out to the west side.  Very dense field of stars mixing up with the cluster’s stars.  (I used M11 as the start of the star hop to this object, and had a nice if not picturesque view of the center of the cluster, its red star reigning over the crowds of faint and fainter stars surrounding.)

IC 1295, PN in Sct, 12.5v, 102”x87”: Unfiltered at 333x a large round haze, mottled through the central region.  OIII and UHC both help.  The edge appears uneven at first but it is really round, with some parts dimmer than others; the south / southeast edge is brightest.  The center is more strongly mottled with the filters.  A second planetary, K 4-8, was plotted on the atlas just to the NW, and I found it blinking with the UHC filter.  A nice contrast in sizes of planetaries in the same field of view.

NGC 6604, OC with nebulosity in Ser, 6.5v, 4’: At 86x and 1° TFOV, the large nebulosity is an irregularly round fairly bright patch around a handful of stars in a shallow arc, with chains of stars stretching to the north and south.  UHC brought out more faint wisps of nebulosity.  Nearby to M16 which was visible in the 80mm finder.

Peimbert Costero PC 19, 12.2v, 14”: PN in Ser:  At 333x, small, fairly faint, bluish, blinks with OIII.  Two close fainter stars make a string with it pointing NW.  I think this was put on the AL PN list to make people research it: Digital images of the PN reveal it looks something like a spiral galaxy with bright “arms” in the SW and NE part of its “halo”.  It is a “Point-Symmetric” PN, meaning the star’s material is being ejected by a bipolar rotating episodic jet, giving it its weird shape. 

NGC 6572, PN in Oph, 8.1v, 16”x13”: “Emerald Nebula”: Very bright and a very beautiful deep green color.  Out of round and orientated N-S.  I think I saw a central star flash out of the very bright central region when using averted vision, very brief.  The edge is hazy and seems to be a diffuse outer shell. 

I made another unsuccessful attempt for Pease 1 in M15.  The globular itself bristled with resolved stars down to the brilliant core, and was very impressive at 333x.  My main struggle to find the planetary is to pick out the “trapezium” stars to begin the star hop on the finder chart.  I eventually just tried blinking with my OIII in the general vicinity of where I thought Pease 1 was, but with no certainty.  Today I went back to blackskies.org and found a good picture of the trapezium stars’ location – turns out I have been searching for them too far away from M15’s core.  I’m hopeful next time out I will be able to find the PN.

NGC 7094, PN in Peg, 13.4v, 99”x91”: Visible in 80mm finder as a stellar point.  @ 333x central star is visible within a round faint moderately large shell; view improves with OIII

NGC 7042, GX in Peg, 12.2v, 2.0’ x 1.8’: I found this easier to hop to from Gamma Equuleus than from M15 where I just was.  @ 205x, fairly faint, pretty large, 3:2 elongated NW-SE, bright core and clearly disrupted diffuse halo [Sb spiral].  Another galaxy in same field, NGC 7043 to the NE as a small, faint round glow with a brighter core. 

NGC 7177, GX in Peg, 11.4v, 3.1’x2.0’: Immediately see a strange sight: the bright core is elongated (barred?) and sits at a sharp angle SW-NW compared to the faint halo, which is E-W 2:1.  Pretty large overall.  The halo has diffuse edges and is mottled. 

NGC 6991, OC in Cyg, 6’x4’ & 12’x8’: At 125x, open cluster who’s brighter loop of stars form an omega or octopus shape, with a bright red star as one of the arms.  A mini little dipper asterism is to the south.  Loose, poor, no concentration or nebulosity.  [It seems I observed John Herschel’s cluster, rather than William’s, which is close to a 5.7 magnitude star to the NE.]

NGC 6997, OC in Cyg, 10.0v, 6’: In the east coast of the North America Nebula; so viewed without filters otherwise it would be obscured.  At 125x, roughly circular arrangement of ~60 stars within a couple magnitudes of each other.  A distinct “S” shape runs through the middle.  Nebulosity apparent even without filters.  A poor, loose, but pretty cluster.   

NGC 6946, GX in Cyg, 9.1v, 11.5’ x 9.8’: “Fireworks Galaxy.”  Its brightness spread over a large area so appears dim; seen through a heavy sprinkle of foreground stars.  Bright small core with three arms easily seen, the most prominent of which sprouts from the core and heads north in a thin line before sweeping and spreading to the east.  Its opposite heads west and is much thicker.  A third is tucked under the north arm in a tighter arc to the core.  I know from prior reading there are several HII regions to be seen in this galaxy but did not bring a finder.  I see one in the NE rim of the northern arm [A4]; a bright oval in the third arm between the north arm and the core [HB481-486]; a nearly detached cloud at the tip of the eastern arm [H1-2]; and a very faint cloud in the gap between the eastern and northern arms [A36-41].  [Identified come HII and star clouds with a finder from Deep Sky Forum.]

NGC 7008, PN in Aquarius, 8.0v, 44” x 23”: Unappealingly called the “Fetus Nebula,” which does, however, describe the appearance fairly well.  Pretty large, it would be oval shape if the SW side of it wasn’t raggedly missing from the rest, with some extensions hanging down from the remaining nebula.  It reminds me a little of one of those broken heart pendants, which is supposed to be matched with a corresponding, missing half.  The NE side is smoothly oval round, and has a bright rim.  Bright star at the SSW rim, the nebula seems to rise up from it like a gene from a bottle.  There are a few stars superimposed on the nebula but there is one in the geometric center.  What a weird sight.

NGC 6824, GX in Cyg, 12.4v, 1.7’x1.2’: Fairly large and oval, 4:3 NE-SW, bright core, stellar nucleus, and diffuse halo.  Star on the southern tip of halo; very bright star just to the north.

NGC 7023, BN in Cyg, 7.1b, 5’: Bright star with extensive milky nebulosity surrounding it.  Seems to have a dark lane to the SW radiating from the star.  Nebulosity permeates the whole view.

NGC 7129, Cluster with nebulosity in Cep, 11.5b, 2.7’: About 7 stars with extensive nebulosity in the area.  7129 forms around three stars in a squat triangle shape.  The nebula seems not just bright but dusty, as if we could see the grains of dust floating in the star beams.

night at the peak

Last night I went to Fremont Peak to support the public viewing night and to give my nearly finished 10-inch f/3.8 a darker sky try-out. I built a Springsonian mount for it; similar to a dobsonian but the axis of altitude rotation is at the eyepiece, not near the primary. I can sit comfortably and view, and move the scope to targets in that hour of right ascension without having to get up from my chair. I used an adjustable observer's chair so when the public guests came to my scope I could have them all sit for a view, no matter what height they were. The configuration proved it's worth when I was able to track the Jupiter/Venus conjunction all the way to the horizon while sitting, not having to contort or scrouch to reach the eyepiece. I used low power the whole night, 35x at 2.3° TFOV (with Paracorr). I have a fantasy about becoming an old school comet sweeper, and this is a good scope for it. It's wonderful for large extended objects and for dreamily scanning the Milky Way, which is pretty much what I did for the night.

SQML at zenith ranged from 20.7 to 20.9 from midnight to 2am. There was a marine layer to help with light pollution but we seemed to lose about half a mpas2 due to light scatter from the smoke. Winds were from the WSW so smoke was blowing over the site, and sometimes we could smell it. The sky from -10° down was badly obscured. When at meridian I could see the major stars making the Capricornus "smile," but no others within it. Fomalhaut shown brightly but I could not see any stars whatsoever below it. I found the Helix in the scope but it was a formless splotch. In the morning I hiked up to the summit. The sky to the south had very thick smoke haze; here's a couple pictures.

The haze, of course, is merely an inconvenience, and will pass. Those who have lost property and the family who lost their father to the fires deserve our compassion and support.