lake sonoma, 30 July

I drove up to Lake Sonoma the night of 30 July to get out from under the Soberanes Fire smoke haze blanketing the south bay. The drive took about three hours from Fremont, with some unusually heavy traffic on 880 to Oakland and 101 by Petaluma. But any frustration was softened by the sky, which became bluer and bluer the further north I travelled.

Dennis Beckley was setting up when I arrived, and we were joined a short time later by Renato del Rosario and Caroline Scolari. Mark Toney and his party of four and more arrived at nightfall. Seeing improved as the night went on, and transparency variable from good to average; SQM was in the 21.4 range. Our equipment started dewing up at nightfall and I’m glad I wired up my telescope for it.

While setting up I noticed a small white thing in the sky to the north-north east; I assumed it was a balloon that broke free from a car dealership’s parking lot display. Several minutes later I noticed it again, and thought it was weird it was the same size as before and near the same place, drifted just a little east. About 20 minutes later Caroline called out that she had it in her 4-inch refractor: it was a Google Project Loon balloon. She said she saw one from Chabot a few days ago and others had identified it there. We were looking at it from below, so it was white, round, and you could see the webs in the balloon radiating from its center. It looked like a strange round jellyfish. The payload, where the WiFi and LTE electronics are carried, was not visible other than a whitish gap in the ribs of the balloon bottom.

I took a rest in my van while waiting for it to get dark, and emerged just in time to see the end of the unusually bright ISS pass to the north. I tried to observe the Io shadow transit of Jupiter which was in progress that hour, but the seeing was too soupy low down and I only glimpsed a dark smudge.

Here are my astronomical observations with my 20-inch reflector:

NGC 1184, galaxy in Cepheus: Very pretty, small edge on. Stellar nucleus with a fairly bright bulging core; halo is tapered to the tips and has a diffuse edge. 4:1 NNE-SSW.

I tried to find Comet 9P/Tempel which was about 3° ENE of Spica. Since early June it travelled from behind Leo straight through the Virgo cluster and provided ample opportunity for views paired with galaxies – but I missed all of that. In early July it was still bright enough to be seen in an 8-inch telescope. Tonight it was to be close by to M-2-35-11, a 1.5’ x 1.5’ 13.1 V magnitude spot between 76 and 82 Virginis. After scanning about at 100x, with and without a Comet filter, I could find neither the galaxy nor the comet. I’ll blame the bad seeing present near the horizon, as even Dennis could not find it despite his computer driven 18-inch scope.

I re-observed M 1-64, “The Other Ring Nebula” in Lyra. I had about as much trouble star hopping to it last month, which was a lot given the density of the field, but was obvious once picked up. It was not as strikingly comet or triangle shaped as last time, and I recall the star its rim touches being brighter. I picked it up at 205x, then went to 333x, and finally 667x. This time I could distinguish the round shape of the nebula and not merge it to the star as a triangle shape. It is small, round and grey, with a fat ring shape and slightly darker middle. Its edges are defined but soft. OIII hurt the view but UHC was the best.

NGC 6826, PN in Cygnus, “Blinking Planetary”: At 333x, the bright central star is obvious, a nice button of a star. The shell at first appeared of even surface brightness with a bluish tinge. It doesn’t really blink but stays steady – I can force it to blink with averted vision but it’s not necessary to blink to see the PN well. While blinking with AV, I see the edges are diffuse and some annularity W-E. With UHC, there is no central star but there are swirls in the blue disk, and I detected what appeared to be a very diffuse detached outer shell.

Nearby to the Blinking Planetary is double star 16 Cygni (aka ΣI 46), a sixth magnitude pair 39” separated. The A has a “C” companion red dwarf with a separation of 73 AU. Both the A and the B are sun like yellow dwarfs, and in 1996 an extrasolar planet was discovered around the B star. But that’s not what brought me. 5.5” to the north are two galaxies. UGC 11465 is 326.6 mly distant, B magnitude 14.4, at 333x was the brighter and larger of the pair, being an oval halo of uneven brightness, with a quasi-stellar nucleus and a brighter core with averted vision. 2.3” to the south (toward 61 Cygni) was a second galaxy, MCG+08-36-003, visual magnitude 14.0 but smaller (0.85’x 0.72’) 349.2 mly distant. In between the two I noticed another very small, extremely faint patch, which when I match my sketch to Aladin appears to be 2MASX J19414452+5-37151; but it is hard to believe I saw this…likely it was a very faint star at my visual threshold.

NGC 6833, PN in Cygnus, at 333x was a very small, fairly faint not stellar point which blinked strongly with OIII.

NGC 6884, PN in Cygnus, at 333x was a small bright disk with diffuse soft edges. Blue-green color, no central star. Seen well without filter; it blinks with UHC.

Open Cluster AI J2005.2+4732 is plotted on the chart nearby so I stopped for a look. It appeared in the 80mm finder as a small faint knot of stars. I still had 333x loaded in the scope; the cluster had about 15 stars of similar brightness in loose concentration. The main group formed a rectangle with an “L” shaped stream of stars near the middle; 6 other stars trailed off to the west. I don’t get any hits on this on the internet. I’d hazard a guess of Trumpler II1p

UGC 11500, galaxy in Cygnus, at 333x was a small elliptical with a brighter core in a very dense field. [B mag 14.4 0.89’x0.748, 335.4mly]. Best to keep bright star 26 Cygni out of field of view. It strikes me that it took modern photographic surveys to reveal many of the galaxies seen through the Milky Way stream, even though some of them are bright enough to be NGCs. I suspect earlier visual observers could not sort out all the surrounding stars.

IC 1301, Galaxy in Cygnus: Small, faint, 2:1 elongation with diffuse edges and a brighter core, stellar nucleus. AV needed to see it well. 5” to west of relatively bright [10.6 mag] star. I’m surprised to see today on Aladin it is a spiral galaxy; 1.4’x0.99’ – I seem to have only detected the core region.

NGC 6764, Galaxy on the Cygnus – Draco border: Very interesting! Not small but not very large, and rather diffuse, orientated ENE-WSW, 4:1. It has four stars intersecting the slightly brighter core perpendicularly, three in a line and one to the east [turns out the northernmost star is the stellar nucleus]. There seems to be an arm reaching out from the ENE tip back around to the north. [The galaxy is a barred spiral, and there is an arm here along with its opposite member to the SW which I did not notice]. 2.5” to the SW is a small, diffuse round patch seen with averted vision [this is PGC 214715, 0.473 x 0.388].

NGC 6742, PN in Draco, at 333x medium size, bright, round with sharp edges. No central star; blinks with OIII.

NGC 7076 (aka Abell 75) PN in Cepheus: At 205x, a bit small, very diffuse, irregularly round with a kind of tail coming out of the southern end and swooping east. Barely there unfiltered; UHC required for contrast. Brighter in the middle of the glow, and a couple of stars in the north and east ends but not centered.

NGC 7139, PN in Cepheus: At 205x unfiltered it is an irregular round glow, medium size. Disappears with OIII but UHC makes it bright. Soft irregular edge and an unevenly bright middle. No central star.

Minkowsky M2-51, PN in Cepheus: “Little Ring Nebula”: Detected at 205x and seen well at 333x. Picked up as a diffuse small round patch unfiltered, on the edge of a keystone asterism. Not visible with OIII but UHC it was cleanly seen. Central star seen with averted vision, and it pops out a fat ring, grey color, with soft edges.

Minkowsky M2-52, PN in Cepheus: Very faint irregularly round small glow, diffuse edges. UHC best contrast; in a dense field. No central star seen.

Around 1:00 am dew formed on my 80mm finder scope’s objective. Luckily I had a chemical hand warmer packet in my gear box and I rubber banded it to the outside of the tube near the objective. I did some low power Milky Way scanning for a few minutes while the warmer cleared the dew, and then I was back in business.

After so much faint stuff, and before trying more of it, I stopped by NGC 7789, Open Cluster in Cassiopeia, Caroline’s Cluster. A distinct patch in the finder, the scope at 86x, 1° field revealed myriad stars, with whorls of dark lanes running through it. It was spectacular.

Abell 82, PN in Cas: At 205x, the central star seen right off, with two other stars involved in the shell, which was a moderately large diffuse round glow best seen with UHC. Lies in the western corner of a triangle of stars.

Vy 1-1, PN in Cas: Small bright slightly bloated star unfiltered. Blinks best with UHC as a small grey disk with well defined edges, no central star.

NGC 7419, small open cluster in Cas: 30 faint stars fanning out from a brighter star in two directions forming an overall triangular shape.

NGC 7635, “Bubble Nebula” in Cas: At 86x, and a UHC filter, it appears as a pretty large irregular grey mass with 4 stars crossing it in a string. Streamers of nebulosity arcing around and away from it, primarily in a NW to SW direction.

NGC 6217 = Arp 185: Barred spiral in Ursa Minor: Viewed at 205x and 333x. Stellar nucleus with a 2:1 NE-SE pretty large halo, brighter core along the major axis. There is an arm from the northern end going east then south, very faint. Brightening on the SE part of the halo [which turns out to be the root of a second arm, oddly emerging from the same side as the first].

While I was studying this last object the others noticed fog welling up from the valleys surrounding the site. It was 2:30am and we were forced to stop. I made a quick sketch before packing in and heading home.

goodbye to jupiter

Observed last night with the 12.5-inch.  I was hoping to catch Ganymede exiting occultation and then entering eclipse by Jupiter's shadow, but the planet has gotten too low now to see it past 10pm.  It's too bad.  But, it will come back.

Had a look at Mars and noted some nice detail.  Seeing was average, so I was pushing it at 340x (with apodising screen and planetary filter).  Aureorae Sinus was the darkest feature, reaching down from the Mare Eryrhraeum as a semi-dark expanse, wisping out to Solis Lacus.  There was an irregular edge below Solis Lacus which was Valles Marineris.  There appeared to be some white ice cap along the upper limb.  To the north Niliacus Lacus swelled up; some mottling along its edge was Nilokeras.

 I tried Saturn too.  Cassini division was certain but did fuzz out with seeing.  Colors were nice, even with the sickly green of the polar region.  Before packing in (a short session as I was tired) I went down to 170x, no filter or screen, and had quite a sharp and pleasing view.  All the detail was there, it was only smaller and needed more attention to find.  There's a lesson there; pushing extremes doesn't always get you results.

I had spent the evening painting the comet sweeper tube.  I want to finish the tube this week so I can focus on the mount this weekend.

telescope building

I spent today putting my comet sweeper telescope together.  I was very careful to measure each key dimension on the tube beforehand, and make sure everything was in order before installing the optics after dinner.  I ran into just a couple problems.  The used Protostar secondary holder had bent vanes, but sandwiching them between pieces of wood and hammering them, I was able to straighten them out.  Then when I installed them into the tube, I found the vanes were installed at the factory backwards, putting my secondary too high up the tube.  After a lot of thought I figured out I needed to drill new holes 1.5 inches lower down -- and this worked.  The University Optics primary cell was very difficult to install, with its three long bolts.  I wouldn't have used it unless I already had it.  Also it is out of level, so one of the collimation bolts needs to be tightened all the way down -- I may need to get a shorter spring.

I used the old dobsonian base to hold the tube while I ran through all my eyepieces to make sure they come to focus, and they do.  The stars looked a little bit pierced, maybe some coma.  It might be due to my not fully tightening the secondary or having it offset yet; or because the primary was not exactly centered in the tube (something I need to improve).  I ran through all the eyepieces again on the moon, and oh what great views.  So much detail and such a wide expanse.  And even through the moon was giving off a bright halo due to some moisture blowing in from the ocean, the sky around it in the eyepiece was dark dark dark, right up to the sharp edge.  I could see some dimming in the 31mm as the moon approached the field stop, along with a bright blue fringe; the effect was less apparent at higher powers.  I am encouraged by the dark sky -- it should mean the primary is very smooth and gives good contrast.

Tomorrow I will disassemble it and begin working on the mount.  And during this week hopefully start finishing it.  I hope to get it running well enough to take out this coming new moon.

lunarian

I've been reading Harold Hill's A Portfolio of Lunar Drawings.  I'm very impressed by it.  Hill spent his whole observing lifetime observing the moon and producing beautiful drawings of it, noting the changes to features at different light angles.  His persistence reminds me that amateur astronomy is, or can be, a lifetime pursuit: one can accumulate a valuable storehouse of knowledge and experience through dedication and leaving oneself open to wonder.  Hill himself admits he had no particular skill making drawings but through years of practice he gained excellent results.  He shows that the interesting and beautifully stark features of the moon are worth looking at -- something that is so contrary to the current prevailing taste for deep sky objects and dark sky viewing, when amateurs rarely observe but once a month during a dark sky expedition.  There is much one can record visually which cannot be captured by a camera or atlases.  There is much to see, and discover, from one's back yard.

And so I was out last night viewing the moon through the 12.5-inch.  It was quarter phase, 51% illuminated.  I pushed the magnification too high at 340x given the watery seeing, but I could discern plenty of fine detail nonetheless.  I was particularly taken with several details:

Montes Alpes: This feature was only half lit, and only the "entry ramp" of the Valis Alpes could be seen heading into the peaks.  Most of the peaks were dark but their summits were illuminated and bright white.  They gave the appearance of an open star cluster of a dozen peaks forming looping chains radiating out from the Valis.  There was a set of ridges spread out like a bird's foot from a common point near where the Valis met the darkness.

Unknown feature: I cannot find this on Rukl, so I will simply describe it: A pair of ridges, or perhaps opposing rims of a ruined crater, curved away from each other at tips like parenthesis ().  Each had central ridges which, with the outline of the base of the hills highlighted against the wide plain in which the feature lay, made it appear as rabbit ears.  Or a deer's hoof print.  

Unknown feature: The rubble of a rock slide spilling out, fan shaped, on the side of a crater wall.

Unknown feature: This was so distinctive I'm surprised and a little frustrated not to find it in Rukl.  Seven craters forming an angle -- four in a line, then about 110 degrees from it three more in a line -- like a compass spread open 110 degrees.  Each of them with nighttime darkness on their floors, but each of them with an illuminated central peak.  It was the oddest thing, to see the craters lined up and then each of them with the same appearance.  The furthest out in the line of three was pierced with depressions on either side, in line with the rest of the craters, as if a meteor had ploughed a grazing path through both walls of the crater.

I will keep searching my printed resources to see if I can identify what I saw.  I had merely made and "X" on a sketch of the finderscope view in my notes to refer me to the location for later -- certainly I will need to take more care to identify surrounding major features while at the eyepiece so I can find the little details later.

some planetaries and more

The night of July 2^nd I met Mark Wagner and Mark Johnston for another session at Willow Springs 3000.  Transparency was very good with some haze around the horizon.  Seeing was variable – pretty good near zenith but not too great lower down; however it did improve overall after midnight.  Besides some of my Astronomical League project list targets, I did some free-range observing, wandering to objects on my Interstellarum Deep Sky Atlas which seemed interesting.  That led me to some unusual finds.  My thanks to Bob Ayers for the use of his property.

All in my 20-inch f/5.25 reflector:

NGC 6070, spiral galaxy in Serpens, @ 205x: Pretty large, fairly bright oval, SW-NE 2:1, with a clearly disrupted low surface brightness halo [which are the SA type spiral arms].  Brighter elliptical core with some knotting.  Faint star on SW tip of halo and two on the NE tip -- could be star forming regions?  [Aladin doesn’t say].  Best to keep bright star to north [HD 145204, 6.64 V] out of FOV.  I failed to notice NGC 6070A or B, just 4' and 5' to the NE.

UGC 10288, edge-on galaxy in Ser, 16 14 24 '-00 12 27, 14.2 V, Sc spiral, 4.023' x 0.483'. @ 205x: Faint edge on of mostly even brightness, gradually brightening to a small elongated core in the middle.  Quite long, 6:1 or more orientated precisely E-W.  DSS image shows a dust lane running the length and even disrupting the eastern tip. Surprised this is not an NGC!

Shane 1 = PN G013.3+32.7, @ 205x: Not too faint (12-13 mag) bloated star; OIII made it into a small round disk which blinks in and out.  Central star tentatively seen.  UHC has a good response.  Small arc of three faint stars just to the west.  Moderately rich field.

NGC 6172, elliptical galaxy in Ser, 12.9 V, 1.0' x 1.0', @ 205x: Small, round bright core with a very small / diffuse halo.  Forms a box with three other stars which lie just to the west.

NGC 6118, "Blinking Galaxy," Spiral galaxy in Ser, @ 205x: [Grand Design Sc II spiral, 4.7' x 2.0', 83mly].  Large, easily seen DV.  Halo is diffuse with ill defined edges, but I detect a gradually brightening center for a core.  3:1 NE-SW.  Why is it nicknamed Blinking?  Perhaps because AV helps it pop out a little from its surroundings; or helps it appear at all in moderate apertures.

NGC 5882, PN in Lupus, @ 205x: Very low (-45d 38m 58s)!  Unfiltered appears as a yellow-white sphere, boiling in the poor seeing with red flashes.  OIII pops it out strongly as a bright, even surface brightness disk with well defined edges.   No central star seen.

Havlen-Moffat 1, open cluster in Scorpius, @ 205x: Spray of 11 brighter stars in field, looks like a miniature Hercules constellation.  Hint of fainter small grey mist of unresolved stars at the bottom of the "keystone."  Bright star preceding.  [III 2 p]

NGC 6453, globular cluster in Sco, @ 333x: GC to 20' NE of M7, in same low power field.  Bright but not very resolved; moderately large irregular mass of unresolved stars behind a scattering of faint stars.  Two brighter stars on the eastern edge of the mass.

Minkowski M1-64, PN in Lyra, @ 333x:  Appears like a comet; fan shaped nebulosity with a star on the northern tip; almost a triangle.  [It is in fact a thick-ringed PN -- round with a dark interior.  The triangle may be an illusion due to the bright star on its rim.  I probably needed to use more magnification to see the ring.  It is, after all, referred to as "The Other Ring Nebula".  13.3 mag / 17.5'' x 17''].

NGC 6713, spiral galaxy in Lyra, @ 333x: [S0 13.4 v, 0.4' x 0.3'] Small, faint, oval slightly elongated ENE-WSW, slightly brighter to the middle with averted vision.  Rich star field.  Interesting to see it given the Milky Way plane is in the way.

Minkowski M1-92, PN in Cygnus, @ 333x: [Pre-planetary nebula, star drives high velocity collimated winds which shape and shock its shell.  11.7 v, 8’ x 16”.]  Very faint, small bloated star.  OIII elongates it very slightly, maybe NW-SE but hard to tell.  It brightens ever so little with blinking.

NGC 6853 / M27, Dumbbell Nebula, PN in Vul, @ 205x: Visible as irregular small grey patch in 80mm finder.  In the scope it is very large, nearly fills the field.  Bright bi-polar lobes SW and NE; apple core shape apparent; SW lobe is brighter.  Central star seen unfiltered in exact center, along with 8 more foreground stars scattered about.  Fainter nebulosity streaked with filaments fill in the empty core sections to complete the overall round shape of the nebula.  Streaks, knots, and condensations throughout the apple core area.  UHC has the best view; more stars and balance with the nebula.

IRAS 19477+2401, 19 49 54.5 +24 08 51, PN in Vul, @ 333x: "Cloverleaf Nebula".  This is plotted in Interstellarum and I “thought” I found it: a faint star which turns into a very small bluish blinking irregularly round glow with OIII; it is part of a triangle of stars of similar brightness.  But, looking at DSS images later I found the nebula is an extremely faint point just to the north side of one of these stars in the triangle, and not the one I thought was the PN.  It would be very cool if it were visible: it is a Pre-Planetary Nebula, a short-lived transition object between AGB stars and aspherical PNs.

Kohoutek K 3-35, PN in Vul, @ 333x: "Seahorse Nebula" [Very young planetary nebula with characteristic S-shaped radio emission morphology… one of two PNs with water maser emission detected -- means it's ejecting water into space!  See link for discussion of how the shape is being formed.]  In the scope, it appeared very small, extremely faint, out of round, and blinked with OIII.   It is the brighter of two very close stars; the other star is to the north and appears as an optical pairing; it doesn’t blink.  This one matched my sketch and a DSS image so I’m fairly confident of the sighting – but feel such an obscure object deserves a return visit for confirmation.

http://journals.cambridge.org/download.php?file=%2FIAU%2FIAU6_S275%2FS1743921310016546a.pdf&code=be230c89b8203e50ae713db408d36660

NGC 6857, emission nebula in Cyg, @ 205x: Pretty bright and large, it is irregularly round with diffuse edges.  OIII helps to bring out more nebulosity especially to a faint smudge heading west from the main body.  Very dense star field.

NGC 6888, EN in Cyg, @ 121x: “Crescent Nebula”:  Wow!  Amazing and large.  Triangle of bright stars to NE with a bright, thin band of nebulosity sweeping west and then south in an arc.  Continuing to the south, the nebula widens into a cloud with a prominent condensation at the SW rim.  Many faint stars interspersed within the nebula.  OIII makes it instantly brighter and completes the arc into an overall oval shape with streaks of nebulosity reaching back from SW to the NE.  But, UHC had the best view given the greater number of stars visible in the dense field.

NGC 6894, PN in Cyg: Unfiltered appears as a thick ring, slightly darker middle.  No central star.  OIII brightens the ring and adds highlights to the center.  There are differing bright and dark areas in the smooth round nebula; it looks like a primary mirror under Foucault test!

NGC 6723, GC in CrA, @205x: "Chandelier."   Large, bright, well resolved to the core.  Chains of stars seem to hang down from a concentration in the northern part of the core, thus its nickname.  Beautiful object. [7.3 V, 11' diameter].

NGC 6726-7, Bright Nebulae in CrA, @ 205x: Two fairly bright stars with nebulosity.  The one to SSW is 6726 [7.2 mag star] and NNE is 6727 [9.5 mag star].  Both nebulae are irregularly round and contact each other; look like porch lights in a fog, one house further away than the other.  To the SSE in the same field is another star with short cone-shaped nebulosity coming from it, appearing like a comet's tail [this is NGC 6729].  To the SW at the edge of the field is a pair of stars with more, fainter nebulosity; this is IC 4812 and it is illuminated by a double star.  There is general haziness in the sky in the view, part of the Corona Australic Molecular Cloud.

IC 1297, PN in CrA, @ 333x: Bright bloated star unfiltered, blinking disk with OIII.  Disk is bright with an even brightness, defined edges.  Central star seen, with very subtle darkening in the middle.  Very faint star on western rim.

NGC 6891, PN in Delphinus, @ 333x: Unfiltered, can see central star with averted vision.  Direct vision it is a disk with defined edges; seems to have an apple core shape within the round shell.  With OIII it has a bluish tinge and the "apple core" inside the disk is better defined.

Patchick 23, PN in Sge, @ 205x: Large (filled 60% of the 0.5* FOV), excessively faint, irregularly round.  Seen only with OIII, appears as a subtle greyscale difference less dark than the dark sky background, and moves with the telescope.  I offer this as a tentative observation; frustratingly I cannot find any information on the internet, even on the Strasbourg ESO catalog – though I’m probably entering “wrong” search terms.  I find some research papers written by Mr. Patchick, but none that reference #23.

Before turning in I made a half-hearted attempt at Pease 1 in M15; but is was past 4am and for the life of me I could not find the “trapezium” of stars which are, on my finder, the starting point to star hop to this object.  Will save it for another time.