OR: Lake Sonoma, Hewett 1

I traveled up to Lake Sonoma to meet up with Muriel to help with the ServoCAT on one of her scopes, and to observe with her, Steve, and Randy and a couple others.  It was clear, with very good transparency, but a bit windy to start, not fully calming down until midnight.  Steve had a SQM reading of 21.4 around that time. 

I travelled light, bringing only my NP101.  I really only had one target in mind, planetary nebula Hewett 1 in Sextans, and had only the hour after astronomical dark to observe it before it set.  It's a large object, so a good small refractor was all that was required.  And a PVS-14 night vision device and filters, naturally.

According to the scientific literature, Hewett 1 is the largest known planetary nebula on the sky with an apparent diameter of about 2° in its brightest portion, corresponding to a linear diameter of 3.5-7.0 pc at the likely distance of 100-200 pc. It is surrounded by an elliptical emission shell with an apparent diameter of 6° × 9°.  A further emission structure, detected northeast of the central star, indicates another shell with a size of 10° × 16° (which is validated by contemporary imagers).  Based on the derived Galactic orbit for the central star PG 1034+001, its thin disk orbit and the morphology of the first halo suggest that the nebula is in an advanced stage of interaction with the interstellar medium.  PG 1034+001 is an extremely hot, helium-rich DO-type star that excites the planetary nebula Hewett 1 and large parts of the surrounding interstellar medium.  It's very unassuming 13th magnitude and is highlighted in the purple box in the below image.  Hewett 1 vies for the "closest" planetary nebula to earth along with SH2-216, at around 425 light-years distant.

As was reported in Astronomy magazine at the time of discovery in 2005, "Most planetary nebulae were discovered in images sensitive to the strong emission lines coming from the nebula’s excited hydrogen. By contrast, Hewett 1 was identified by emission lines from oxygen in the spectra of many background galaxies and quasars observed as part of the Sloan Digital Sky Survey. The nebula’s large size caused many spectra to show oxygen’s characteristic emission-line signature."  

Having aligned my DSC I pointed my scope at NGC 3325, one of these background galaxies, which was slightly offset from the center of the nebula.  The NP101 with a 67mm Plossl+ has a 5-degree TFOV, and a magnification of 8x.  Flipping through the filters on my filter wheel, I immediately noticed a fairly faint elongated glow in a loose trapezium asterism with direct vision, no trouble at all. I flipped through various filters and could see it in Ha+OIII dual band, but 3nm Ha was best.  I was shocked I would find it so easily and called Steve over to have a look.  I asked him to look at the trapezium asterism and flipped the filter wheel to Ha while he was viewing through the eyepiece, and he too could easily see the nebula.  I remembered there was to be a larger outer shell to the northeast of the brightest central region, so I moved the scope in that direction.  With the brighter central region along one side of the field stop, I noticed a wide, long, curved, very faint contrast change with an obvious cut-off along the outer (northeastern) part of the arc.  It was quite difficult, and I moved the scope side-to-side to confirm it moved with the sky and wasn't an aberration.  I sketched what I saw intending to confirm it later.

Today, using Roman Perah's Hewett 1 - AstroBin, I matched the loose trapezium of stars the extent of the relatively brighter glow we saw, and also the gently curving ridge to the northeast:

North is to the lower left corner, east to the lower right corner; green outline of the portions I saw.

Bray Falls' image Hewett 1 - The Giant in Sextans - AstroBin (north down) shows the entire extent including the large outer shell (not seen by me) and greater detail of the bright areas, including what appear to be shadows cast by nebulous pillars on a sheet of nebula behind them -- in line with what would be PG 1034+001's glow:  

I was exhilarated and very happy to have achieved that night's mission.  I spent the rest of the time scanning with the NP101 both visually and with the PVS-14, not taking notes but revisiting old favorites.  A very nice night out.

1 june 2026: big burnham night

Seeing was good last night, even for low elevations, with average transparency.  My 20-inch is out of action for the moment due to bent caster supports -- I dare not move the shed, since I think the wheels would collapse.  I have replacement, hopefully stronger wheels on order.  

I decided to take a break from my telescope projects and experimentation and spent the night actually observing.  I used my 6-inch f/15 refractor on Burnham double stars, mostly ones which he discovered with his 6-inch f/15 Clark.  It's fun to test myself against the master, and my scope too.  I replaced my Edmund objective (which I had to ATM mount into the cell since it is slightly undersized) with a Jaegers, which can be hit-or-miss optically.  I had nice airy disks and complete single ring diffraction patterns, and a good star test, so I feel good about it.  And it could keep up with Burnham's pairs, able to split at the resolution limit, and to detect out-of-round for sub-limit pairs.  It would be good practice to view single stars under high powers to have a reference point in memory to detect out-of-round shapes.

I observed a number of pairs low to the south--most of the 6-inch Burnham pairs at this RA are south, I wonder if he thought the north was well covered already by the Struves, so he thought to explore more to the south where the Struves would have had more difficulty?  Fortunately, my scope is mounted on a tall platform so it could see over the 8' fence in my yard.  And more fortunately still, I have a gap in the bushes which overtop the fence in my neighbor's yard, providing a slot through which I could see the pairs.  Based on photos, I think my scope it placed a bit taller than Burnham's.  

Halfway through the night I switched from my Leica zoom to my Baader classic ortho set on a turret -- the Leica is much more convenient to use but I found I needed a bit more power, and rather than change eyepieces I like to be able to switch quickly. 

BU 799 AB: 152; 250x: Very closely separated, clean split, 2 Dm.  A is blue-white, B is dull orange.  Very faint wide C.  SOC grade 5 orbit 1658-year period, 0.6" at discovery with the 15-inch Washburn.  49% PRO, 174 AU WS, 2.5+1.6 Msol, it is likely binary.

13h 04m 49.78s +73° 01' 29.8" P.A. 266.00 sep 1.3 mag 6.60,8.45 Sp A7IV dist. 120.19 pc (392.06 l.y.)

BU 221 AB: 152; 250x: Very faint light orange B, split, 1 Dm from A.  92% PRO, 444 AU WS, 2.6+1.9 Msol, it is most likely binary and needs an orbit.
13h 13m 15.56s -15° 27' 37.6" P.A. 46.00 sep 1.7 mag 8.26,9.53 Sp K0III dist. 561.8 pc (1832.59 l.y.)

BU 342 AB: 152; 250x: Slightly unequal, well split.  74% PRO, 729 AU WS, 1.8+1.7 Msol, it is probably binary and needs an orbit.

13h 15m 14.35s -18° 55' 11.8" P.A. 35.00 sep 4.0 mag 8.68,9.04 Sp F2V dist. 163.13 pc (532.13 l.y.)

BU 222 AB: 152; 250x: Unequal light blue-white stars, good split. 94% PRO, 247 AU WS, 1.7+1.4 Msol, it is likely binary and needs an orbit.

13h 17m 23.84s -21° 32' 16.5" P.A. 22.00 sep 1.8 mag 8.25,9.19 Sp A9III/IV dist. 154.8 pc (504.96 l.y.)

BU 610 AB: 152; 250x: Very faint B just barely seen direct vision.  Well separated, excellent pair.  86% PRO, 375 AU WS, 2.2+0.9 Msol, it is likely binary and needs an orbit.

13h 23m 57.08s -20° 55' 28.5" P.A. 18.00 sep 4.3 mag 6.61,10.11 Sp G8III dist. 156.01 pc (508.9 l.y.)

BU 460 AB: 152; 250x: Very delicate 2 Dm split.  -51% PRO, it is not binary.

13h 25m 03.73s -15° 37' 56.5" P.A. 41.00 sep 2.0 mag 7.92,9.93 Sp A6IV dist. 117.65 pc (383.77 l.y.)

BU 1107 AB: 152; 250x: Very fine near equal close split.  -64% PRO, it is not binary.

13h 27m 07.86s -22° 21' 54.5" P.A. 131.00 sep 1.5 mag 8.83,8.94 Sp F6V dist. 92.51 pc (301.77 l.y.)

BU 113 AB: 152; 250x: Very faint but plainly seen B, closely split.  -84% PRO, it is not binary (in spite of SOC grade 5 orbit).  

13h 29m 06.11s +11° 28' 10.1" P.A. 272.00 sep 1.7 mag 8.73,10.66 Sp K0 dist. 58 pc (189.2 l.y.)

BU 114 AB: 152; 250x: Unequal fine split, dull orange stars.  25% PRO, 90 AU WS, 1.3+1.2 Msol, it's possibly binary and needs an orbit.

13h 34m 17.72s -08° 37' 07.4" P.A. 174.00 sep 1.4 mag 8.05,8.18 Sp F8V

BU 933 AB: 152; 175x: Unequal, well split.  At zenith.  1% PRO, 305 AU WS, 1.3+1.0 Msol, probably not binary.

13h 34m 34.66s +33° 08' 08.7" P.A. 23.00 sep 2.8 mag 9.04,9.69 Sp F8 dist. 116.96 pc (381.52 l.y.)

BU 611 AB: 152; 250x: Well split B seen with averted vision only.  66% PRO, 1,050 AU WS, 1.6+0.9 Msol, RVD 2.0 < EV 2.1, it is possibly binary and needs an orbit.

13h 37m 41.55s -14° 43' 46.3" P.A. 262.00 sep 4.8 mag 9.54,13.00 Sp F3V

BU 612 AB: 152; 760x: Very subtle out of round with the bump being dimmer, all high powers through 760x.  No Gaia parallax data.  SOC grade 1 orbit, 22.46-year period, it will be at apastron at 0.3" (the discovery separation) during 2030.  Discovered with the 18.5-inch Dearborn.  

13h 39m 34.68s +10° 44' 46.7" P.A. 165.00 sep 0.2 mag 6.35,6.47 Sp F1V dist. 59.99 pc (195.69 l.y.)

BU 223 AB: 152; 125x: Very faint wide B, needed foveal coaxing to hold it direct.  7% PRO, 2,406 AU WS, 1.7+0.9 Msol, but RVD 2.3 > EV 1.4, it is not binary.
13h 45m 10.43s -03° 18' 54.8" P.A. 343.00 sep 18.9 mag 8.26,10.86 Sp A5 dist. 176.99 pc (577.34 l.y.)

BU 115 AB: 152; 250x: Very difficult.  B is the barest of flecks at A's diffraction ring.  With seeing. Burnham discovered at 1.42", more difficult than now. -55% PRO, it is not likely to be binary, in spite of SOC grade 4 800-year period orbit.

13h 45m 20.87s +09° 03' 28.6" P.A. 260.00 sep 1.6 mag 7.53,10.40 Sp G5 dist. 54.67 pc (178.33 l.y.)

At this point I switched to orthos in a turret -- I had been spending most of my time until now with the highest power on the Leica, and since I have a 6mm on the turret I could go a bit higher if needed:

BU 935 AB: 152; 380x: B is a very subtle brightened small smudge on A's diffraction. Burnham discovered at 1.6" and with the 18.5-inch, and he says: "Both components of Struve's rejected pair [STF 1780] were found to be double with the 18.5-inch.  With a large aperture it is one of the finest of the quadruple groups."  No Gaia data.

13h 45m 56.33s -12° 25' 35.6" P.A. 304.00 sep 1.0 mag 5.66,8.47 Sp G8III dist. 124.69 pc (406.74 l.y.)

BU 413 AB: 152; 125x: Surprise! Deep orange-red and 2 Dm wide blue.  Very pretty pair.  W Hydra.  No Gaia parallax data.

13h 49m 02.00s -28° 22' 03.5" P.A. 106.00 sep 66.8 mag 7.79,9.59 Sp M8e dist. 104.28 pc (340.16 l.y.)

BU 343 AB: 152; 380x: Suspected double with 250x, strongly notched overlapping disks with 380x, it wants very much to split!  White stars.   No Gaia parallax for the secondary.  SOC grade 3 orbit, 255-year period, will increase separation a couple tenths by 2040.  Discovered at apastron 1.2"

13h 52m 00.97s -31° 37' 09.2" P.A. 187.00 sep 0.9 mag 6.26,8.91 Sp F7V dist. 52.69 pc (171.87 l.y.)

BU 462 AB: 152; 175x: Faint near equal white stars, seen with 175x, better with 250x.  -16% PRO, though the other data is ok: 486 AU WS, 1.5+1.5 Msol, RVD 0.0 < EV 3.3, low PMV 0.09, it is probably not binary.

14h 30m 00.48s -03° 43' 14.3" P.A. 323.00 sep 2.1 mag 9.92,9.90

BU 117 AB: 152; 250x: Close split, unequal.  2% PRO, 74 AU WS, 1.0+0.8 Msol, there is a possibility it is binary, an orbit should be tried.

14h 31m 19.74s -15° 38' 19.5" P.A. 71.00 sep 1.4 mag 8.44,9.36 Sp G5V dist. 42.37 pc (138.21 l.y.)

BU 616 AB: 152; 125x: Faint superwide B.  Why bother?  -73% PRO it is not binary.  Burnham concluded it was not binary based on the proper motions.

14h 32m 04.76s +38° 18' 28.4" P.A. 123.00 sep 53.0 mag 3.04,12.70 Sp A7III dist. 26.61 pc (86.8 l.y.)

BU 1112 AB: 152; 380x: Flashes of a fleck beyond A's diffraction ring; with better seeing can hold it continuously.  -25% PRO, it is not binary.  Discovered with the 12-inch.

14h 33m 09.69s -30° 42' 51.6" P.A. 14.00 sep 2.7 mag 6.23,9.86 Sp K0III dist. 101.21 pc (330.15 l.y.)

BU 238 AB: 152; 125x: White A and faint wide blue B, seen at 70x, better view at 125x.  -41% PRO it is not binary.

14h 33m 46.23s -21° 02' 01.9" P.A. 88.00 sep 6.9 mag 8.51,10.50 Sp A2V dist. 152.21 pc (496.51 l.y.)

BU 226 AB: 152; 380x: Exquisitely fine, near equal, hairline split with seeing.  No Gaia parallax data.  Discovered with the 6-inch at 0.80", so this was an exact repeat of Burnham's observation!

14h 38m 54.63s -22° 19' 42.2" P.A. 124.00 sep 0.8 mag 7.89,8.41 Sp A2V dist. 194.93 pc (635.86 l.y.)

BU 345 AB: 152; 250x: Beautiful clean close split, unequal.  With 250x & 380x.  No Gaia parallax data.  6-inch discovery.

14h 41m 46.12s -29° 41' 51.4" P.A. 284.00 sep 0.9 mag 7.63,8.10 Sp A5III

BU 414 AB: 152; 250x: Difficult, with seeing, 1 Dm secondary flashes of split from A.  93% PRO, 303 AU WS, 3.6+2.9 Msol, it is likely binary and needs an orbit.

14h 41m 51.23s -30° 55' 59.2" P.A. 347.00 sep 1.0 mag 6.75,7.62 Sp ApSi dist. 353.36 pc (1152.66 l.y.)

BU 346 AB: 152; 125x: Lovely white unequal, nicely split at 70x and 125x. No Gaia parallax for the primary.  SOC grade 5 orbit 2000-year period a good a guess as any.

14h 48m 31.71s -17° 20' 24.4" P.A. 279.00 sep 2.8 mag 7.48,7.92 Sp G1V dist. 44.5 pc (145.16 l.y.)

BU 617 BC: 152; 380x: A is a nice orange color, B wide and blue.  C is seen with averted vision and high power as a brightened smudge.  Component of H 6 117.  No Gaia data for C.  
14h 49m 15.71s -24° 15' 54.2" P.A. 343.00 sep 2.9 mag 8.57,11.00 Sp F3V

BU 106 AB: 152; 250x: Unequal white stars, lovely close split, pure white and clean view with 125x and 250x.   No Gaia parallax data for A.  SOC grade 4 orbit 614-year period.

14h 49m 19.09s -14° 08' 56.3" P.A. 8.00 sep 1.9 mag 5.61,6.62 Sp A1pSrCrEu dist. 72.94 pc (237.93 l.y.)

BU 347 AB: 152; 125x: Not difficult, wide faint B, A is yellow -- not an obvious pairing, maybe Burnham measured it due to the star color?  -43% PRO it is not binary.
14h 54m 37.92s -33° 18' 02.0" P.A. 319.00 sep 13.3 mag 6.00,11.00 Sp K2III dist. 320.51 pc (1045.5 l.y.)

BU 239 AB: 152; 380x: White pair, at 250x seen as a bean-shaped elongation, overlapping of unequal disks with 380x. No Gaia data for the primary.  Discovered with the 6-inch at 0.8" (he probably had a clean split).

14h 58m 39.26s -27° 39' 26.3" P.A. 16.00 sep 0.5 mag 6.17,6.79 Sp A8III dist. 113.12 pc (369 l.y.)

BU 348 AB: 152; 380x: Teardrop of overlapping unequal disks.  No Gaia parallax data. Discovered with the 6-inch at 0.47" -- likely the same view as mine.
15h 01m 48.92s -00° 08' 24.9" P.A. 105.00 sep 0.4 mag 6.13,7.49 Sp M0.5IIb dist. 704.23 pc (2297.2 l.y.)

BU 119 AB: 152; 125x: Beautiful unequal white stars, close split with 125x, a very clean view.  93% PRO, 117 AU WS, 1.1+1.0 Msol, and RVD 0.6 < EV 5.7, it is binary.  SOC grade 4 orbit 1348-year period.

15h 05m 31.91s -07° 00' 48.8" P.A. 273.00 sep 2.4 mag 8.09,8.76 Sp G0 dist. 47.6 pc (155.27 l.y.)

BU 227 AB: 152; 250x: Finely split unequal light orange stars, 1 Dm.  10% PRO, 198 AU WS, 1.8+1.4 Msol, it might be binary and an orbit can be tried.
15h 19m 09.19s -24° 15' 53.9" P.A. 163.00 sep 2.0 mag 7.53,8.64 Sp K1III