more doubles

A good night and better seeing; 7/10 and 3/5 transparency.  I adjusted the Webster sling in hopes it would solve the astigmatism, but no go.  Rear fan still vibrating.  Stars seem more still without boundary layer fans.  Rings outside of focus, mess inside.   8" mask almost throughout.  Getting the hang of star hopping using the hand controller; a very useful skill.

STF 1723: 20" 205x: Light yellow and light orange, 1.5 delta mag, well split.

13h 08m 13.49s +38° 44' 20.2" P.A. 12 sep 6.4 mag 8.67,10.08 Sp G2IV-V dist. 73.05 pc (238.29 l.y.)
STF 1692 = Cor Caroli: 8" 205x: Cream white and light canary yellow.  Well separated, 2 delta mag.
12h 56m 01.67s +38° 19' 06.2" P.A. 229 sep 19.3 mag 2.85,5.52 Sp A0pSiEuHg dist. 35.2 pc (114.82 l.y.)

STT 261: 8" 205x: Light yellow-white equal pair, ~1.5".
13h 12m 02.02s +32° 05' 07.9" P.A. 338.3 sep 2.61 mag 7.40,7.64 Sp F6V dist. 72.52 pc (236.56 l.y.)

STF 1768: 8" 205x: Very tight pair, a little more than hairline split, ~2 delta mag.  8" 333x: white and dull blue, ~1", Nice!
13h 37m 27.70s +36° 17' 41.4" P.A. 93.9 sep 1.67 mag 4.98,6.95 Sp A7IV dist. 60.9 pc (198.66 l.y.)

STF 1769: 8" 333x: Wide separated blue stars, half delta mag.  2+1 system?  1 delta mag fainter star quite more widely separated. [Sextuple system; I missed the 1.6" AB, need to re-observe; saw the AC pair only -- the fainter star noticed may be part of the system.]
13h 38m 01.95s +39° 10' 41.0" P.A. 45 sep 1.6 mag 7.91,10.42 Sp G5 dist. 46 pc (150.05 l.y.)

S 634: 8" 333x Pair of orange stars of equal magnitude widely separated at either end of the FOV.  There are two faint blue pairs closer in to one of these. [The orange and the blue are the pair; though it's a surprise since the two orange stars look identical, may have formed together?]
12h 11m 22.93s -16° 47' 27.1" P.A. 302 sep 4.7 mag 7.17,8.79 Sp G6V dist. 32.34 pc (105.49 l.y.)

Since I had covered this part of the sky the night before, I moved to someplace new: Libra

Hld 20: !! 8" 205x: Orange star but no companion.  20" 333x Seeing distorted but a much fainter orange star seen as a point outside the diffraction, 5-6"; very fine!  Put 8" on @ 333x and can't see the B star!
14h 45m 57.78s -15° 27' 34.4" P.A. 249 sep 4.7 mag 6.48,10.10 Sp K1III dist. 444.44 pc (1449.76 l.y.)

BU 106: 8" 333x: Close, 1.5-2", half to one delta mag, off-white stars. [AB seen; three additional pairs seen.]
14h 49m 19.09s -14° 08' 56.3" P.A. 6.8 sep 1.95 mag 5.61,6.62 Sp A1pSrCrEu dist. 72.94 pc (237.93 l.y.)
BU 119: 8" 667x: Too much power, too dim and seeing too choppy.  8" 333x perfect, clean and well split ~2" near equal, slightly orange. [AB]
15h 05m 31.91s -07° 00' 48.8" P.A. 273.9 sep 2.32 mag 8.09,8.76 Sp G0 dist. 47.6 pc (155.27 l.y.)

STF 3091: 8" 333x White with very much fainter wide blue B. [AB,E seen; missed AB 0.5"]
15h 16m 01.56s -04° 53' 52.3" P.A. 46 sep 41.3 mag 7.30,12.00 Sp F8V dist. 62.54 pc (204.01 l.y.)

STF 1899:  8" 333x White with very much fainter wide blue B. 
15h 01m 35.34s -03° 09' 50.5" P.A. 67 sep 28.3 mag 6.69,10.15 Sp K2IV+K0V dist. 109.29 pc (356.5 l.y.)
BU 349: 20" 333x, B star easily seen despite diffraction.  Can only see with 8" 333x after first having seen it in the 20", and even then need averted vision to bring it out.
15h 08m 57.33s +01° 41' 21.4" P.A. 38 sep 3.3 mag 7.59,10.94 Sp F1V dist. 88.65 pc (289.18 l.y.)

BU 348AB: 8" 333x, suspect elongation.  8" 667x, definite elongation.  8" 447x, best/cleanest view, clearly elongated.  20" 667x & 447x, view is too messy
15h 01m 48.92s -00° 08' 24.9" P.A. 108 sep 0.5 mag 6.13,7.49 Sp M0.5IIb

Jupiter: 8" 447x & planetary filter: No purple festoons in equatorial band; replaced by a ochre colored mess.  Dark rust colored S tropical belt, and a thin line of a band in the southern zone.

battling astigmatism

I'm not completely sure where it's coming from, either the fans/thermals or the mirror sling, but I'm determined to replace both on the scope.  The astigmatism persisted all night, and I could only use the 8" mask to mitigate the effect.  If I can't use this scope at full aperture, what's the point?  So I'll spring for the Glatter sling (to replace the poorly designed Webster sling, which has no means of automatically adjusting for mirror height) and to suspend a boundary layer fan over the primary.  Orders to be placed today.  Must needs.

Otherwise it was a satisfying night with the 8" mask.  Seeing 6/10, Transparency 3/5.  I'm surprised I'm enjoying it so much.

Dubhe = BU 1077: I used this as my second alignment star, and thought I saw a fine point in the 23mm reticle very close to the primary.  I tried other various combinations, with the mask, high magnification, low, 8" and 20", and with a Wratten #12 filter -- I kept thinking I saw a Sirius B like fine point.  However given the amount of astigmatism I've been having I rather doubt it.  So I'll leave this one to be observed later.
11h 03m 43.84s +61° 45' 04.0" P.A. 337.6 sep 0.8 mag 2.02,4.95 Sp G9III dist. 37.68 pc (122.91 l.y.)

STF 1758: 8" 205x: Nice near equal pair, slightly yellow, ~5"
13h 32m 51.51s +49° 08' 24.3" P.A. 290 sep 3.3 mag 8.70,8.95 Sp G0 dist. 77.04 pc (251.3 l.y.)

Bgh 50: 13x80mm Finder split.  Wide pair, 2 delta mag, dull white.  Viewed 8" 205x, no apparent other doubling.
14h 04m 45.95s +25° 49' 03.9" P.A. 32 sep 97 mag 7.00,8.90 Sp F5+K0 dist. 44.01 pc (143.56 l.y.)
NGC 5466: Globular Cluster in Boötes.  Invisible with 8" 205x, but at 20" 205x it was very faint and fairly large (about 60% the FOV).  A few brighter members scattered but mostly a mist of very faint blue stars, just barely resolved.  Stopped by this one while star hopping to other doubles.

STF 1812: 8" 205x: Is it a 2+1 system?  Main pair 2.5 delta mag, pretty wide; there's a third, fainter pair about 4x the other separation.  [AB is STT 277, 0.2" not seen.  AB,C seen, and yes there is another pair AB,D 7.88/12.10 72.4"]
14h 12m 26.68s +28° 43' 02.3" P.A. 108 sep 14 mag 7.88,9.45 Sp F2V dist. 1000 pc (3262 l.y.)

STF 1816: 8" 205x.  Wide, very faint B; how thought was binary?  [I got this one wrong!  Very close separation now, at closest approach; 1.6" at discovery.  Need to retry when the 20" is fixed.]

14h 13m 54.63s +29° 06' 19.5" P.A. 100.3 sep 0.35 mag 7.43,7.75 Sp F0+A2 dist. 113.38 pc (369.85 l.y.)

STF 1850: 8" 205x Very wide, 1/2 delta mag.

14h 28m 33.29s +28° 17' 25.9" P.A. 262 sep 25.1 mag 7.11,7.56 Sp A1V+A1V dist. 349.65 pc (1140.56 l.y.)

STT 289: 8" 205x: Noticed a very much fainter star emerge with averted vision then could hold direct.  Very fine, well split.  8" 410x: Tried to bring out the B star with higher magnification, but oddly it disappeared.  Curious.  20" 410x: B star easily seen though the disks are bloated, seeing not good.
14h 55m 58.63s +32° 18' 00.3" P.A. 109 sep 4.8 mag 6.20,11.10 Sp A2V dist. 95.79 pc (312.47 l.y.)

STFA 27: 8" 205x.  Bright star with many nearby faint star.  Didn't bother trying to figure out which are which. 

15h 15m 30.16s +33° 18' 53.4" P.A. 78 sep 105 mag 3.56,7.89 Sp G8IIICN-1 dist. 37.34 pc (121.8 l.y.)

STFA 28: 8" 205x.  Bright A star does not seem round.  B star is a tight equal pair.  Pretty set. [Aa,Ab is CHR 181 0.1", and I'd be shocked if I actually detected it.  STFA 28 is technically the bright star and the tight pair; the tight pair is Ba,Bb = STF 1938, 7.09/7.63, 2.2"]
15h 24m 29.54s +37° 22' 37.1" P.A. 171 sep 108.2 mag 4.33,7.09 Sp F2IVa+G0V dist. 34.69 pc (113.16 l.y.)
STT 298: 8" 205x.  At zenith, but worth the effort to slew to.  Another great 2+1.  The tight pair [AB] is near equal and split a little more than a hairline.
15h 36m 02.22s +39° 48' 08.9" P.A. 188 sep 1.21 mag 7.16,8.44 Sp K2V dist. 22.31 pc (72.78 l.y.)

Ku 108: 8" 205x. White A and reddish B stars.  Wide, 2 delta mag.  [Need to try this with the 20": BC = RAO 18 9.74/11.00 0.4"]
15h 27m 40.35s +42° 52' 52.9" P.A. 319 sep 40.7 mag 7.55,9.74 Sp G5 dist. 32.13 pc (104.81 l.y.)

STT 296: 8" 205x: Very fine but well split, ~2", yellow-white A, reddish B, 2 delta mag.  [AB seen]
15h 26m 26.56s +44° 00' 13.2" P.A. 274 sep 2.2 mag 7.83,9.09 Sp G5 dist. 87.95 pc (286.89 l.y.)

STT 301: 8" 205x: Another wide mag difference, ~4 delta mag.  B is faint but well split, ~5".
15h 46m 13.64s +42° 28' 06.3" P.A. 27 sep 4 mag 7.50,10.38 Sp K0 dist. 216.45 pc (706.06 l.y.)

WNO 47: 20" 205x.  Did not see faint B star in 8", so switched to 20".  Wide split and faint; nothing too special visually, but intellectually, per CDSA: "Local, high CPM, low mass double, AB: ps = 13,70 AU (2000).
16h 04m 56.79s +39° 09' 23.4" P.A. 280 sep 70 mag 6.66,12.86 Sp K0V dist. 14.52 pc (47.36 l.y.)

I tried for Jupiter at the end of the night, as it had just cleared the meridian tree -- but it was too low for this scope to reach it.  The 20"s mirror is much lower than Big Blue's, so it will struggle with planets.  I guess that's what my 8" f/7 is for.

another night out

Again with the 20", but seeing was middling & transparency poor, so I mainly used the 8" mask.  I still have astigmatism problems, and I can't figure out if it's the mirror cell or thermal.  Maybe both.  But I do need to fix it if this scope is to be productive.

STF 1888: 8" 205x  A very pretty light yellow with 2 delta mag. light orange B, ~5".  AB seen.
14h 51m 23.38s +19° 06' 01.7" P.A. 297.9 sep 5.3 mag 4.76,6.95 Sp G8V+K5V dist. 6.71 pc (21.89 l.y.)
STF 1919: 8" 205x  Pretty wide separated stars, both white with a tint of yellow.  Half delta mag.
15h 12m 43.48s +19° 17' 09.8" P.A. 11 sep 23.4 mag 6.71,7.38 Sp G1V+G5V dist. 27.24 pc (88.86 l.y.)

Ho 575: Tried a variety of combinations for this one:
8" 205x: Light orange star; no double seen
8" 410x: no double seen
8" 667x: Still none -- A is steady & round
20" 667x: Light orange A messy by airy disk is there.  The B star reveals itself, 5" and a hazy blue.
20" 410x: Disks are smaller, B more clearly resolved.
20" 333x: Best star images.
Transparency is poor -- I can smell the water vapor in the air, like the approach of rain -- likely adding to the extinction. 
19h 18m 47.20s -05° 46' 20.9" P.A. 10 sep 5.8 mag 8.03,11.65 Sp A0 dist. 223.21 pc (728.11 l.y.)

Back goes the aperture mask for a dimmer, if cleaner, view.

STF 1950: 8" 333x  Dull orange A, 1.5 delta mag, B ~4", a flatter orange color.
15h 29m 58.46s +25° 30' 31.1" P.A. 93 sep 3.4 mag 8.07,9.23 Sp K4III dist. 485.44 pc (1583.51 l.y.)

STF 1932: 8" 333x  Near equal, yellowish white, ~2"
15h 18m 20.19s +26° 50' 24.7" P.A. 266.8 sep 1.62 mag 7.32,7.41 Sp F6V+F6V dist. 35.98 pc (117.37 l.y.)

STF 1937: 8" 333x  Suspect elongation.  8" 667x definite egg shape.  20" 667x: Can't get a good focus.
15h 23m 12.23s +30° 17' 17.7" P.A. 256.1 sep 0.39 mag 5.64,5.95 Sp F8V+G0V dist. 17.86 pc (58.26 l.y.)

finally a decent session

Seeing & transparency were mediocre, however I did have my first "good" session with the 20" last night.  I modified the rear fan to attach it to the holding plate with silicone, and used cut-up mouse pad material as a barrier when screwing into the cell -- it seemed to improve the vibration but I turned the fans off during observation anyway.  I also added a focuser baffle.  I used the 8" off axis mask almost the whole time.  I need to relearn my separation estimates given the new aperture and magnifications I'm using.

STF 1639: 205x White and slightly blue pair; close, around 3"? [AB seen; AC much further out 91"]
12h 24m 26.81s +25° 34' 56.7" P.A. 322.8 sep 1.85 mag 6.74,7.83 Sp A7V+F4V dist. 90.25 pc (294.4 l.y.)
Sh 143: 205x Wide separation white and bluish, 3 delta mag.  Feel like there is a fainter star closer in and 90 degrees PA from the B star.  [AB is the fainter pair, 4.86/11.8 36.7"; AC is the main pair described.]
12h 22m 30.32s +25° 50' 46.3" P.A. 168 sep 59 mag 4.86,8.90 Sp G0III-+A3 dist. 90.33 pc (294.66 l.y.)
Hjl 1069: 205x Lovely wide pair, 2.5 delta mag.  Clean image.
12h 30m 19.91s +21° 56' 53.6" P.A. 312 sep 115.4 mag 7.85,10.12 Sp G7III dist. 139.28 pc (454.33 l.y.)
24 Com = STF 1657: 205x Very pretty bright light orange and fainter blue, wide separation.  Such a sight!
12h 35m 07.76s +18° 22' 37.4" P.A. 272 sep 20.4 mag 5.11,6.33 Sp K2III dist. 138.12 pc (450.55 l.y.)

STF 1687: 205x Rich light yellow and much fainter wide blue B.  Near M64.  [Need to re-observe.  I saw the wide AC, but not the AB which is 5.15/7.08 1.2"
12h 53m 17.77s +21° 14' 42.1" P.A. 200.9 sep 1.18 mag 5.15,7.08 Sp G7III dist. 86.81 pc (283.17 l.y.)
Met 9: 8" 205x nothing.  8" 410x suspect elongation.  667x see a fleeting, bluish point just outside of first diffraction ring.  A is light yellow orange and bright; 2 delta mag. to B.  A feels elongated / egg shaped.  At 20" and 667x the seeing is too messy though there is a knot in the diffraction where I had noticed the point with 8".  Strong feeling A is elongated.

12h 54m 39.98s +22° 06' 28.8" P.A. 51 sep 1.7 mag 5.70,7.77 Sp F8V+M2-3V dist. 33.85 pc (110.42 l.y.)

39 Com = Cou 11: 8" 667x: Probably 3" separation, 2 delta mag. [mis-judged the separation]

13h 06m 21.28s +21° 09' 12.6" P.A. 314 sep 1.8 mag 6.10,8.75 Sp F4V dist. 49.68 pc (162.06 l.y.)

Bgh 46: 13x Wide finder split, 1 delta mag, not much to recommend.  Triangle of stars to the south, pointing to Bgh 46.  [I did look at this at 667x to see if one of the wide pair had a pair of its own, but did not scrutinize well enough.  This one should try on a really good night with 20": HDS1862 = Aa,Ab 6.56/9.69 0.4".]
13h 16m 32.26s +19° 47' 07.0" P.A. 58 sep 203.1 mag 6.46,7.59 Sp A3+A2 dist. 85.4 pc (278.57 l.y.)

Bu 800: 8" Lovely yellow and orange, very pretty; wide separation, 2.5 delta mag. [AB seen]
13h 16m 51.05s +17° 01' 01.9" P.A. 104.8 sep 7.79 mag 6.66,9.50 Sp K1V+M1V dist. 11.07 pc (36.11 l.y.) 

STF 1884: 8" 333x: White, fairly close ~3", half delta mag.
14h 48m 23.37s +24° 22' 01.0" P.A. 56 sep 2.3 mag 6.58,7.48 Sp F8IV-V dist. 84.67 pc (276.19 l.y.)

Izar = STF 1887: 8" 333x: A yellow, messy with seeing; B nice light blue and clean.  A seems egg shaped, slightly elongated perpendicular to B's PA. [No second star with A.  I wonder if elongation is coming from the mask being vignetted , or maybe astigmatism?]
13h 54m 57.46s +87° 23' 44.1" P.A. 226 sep 3.3 mag 9.18,11.20 Sp B9 dist. 176.99 pc (577.34 l.y.)

Cou 610: [I tried this one a year ago with the 30"]  8" 667x: Notched/snowman at best moments.  B definitely fainter and almost blue.  Very faintly split, looks like a blue appendage.  20" too messy.
15h 32m 55.78s +31° 21' 32.9" P.A. 199 sep 0.8 mag 4.27,6.29 Sp B6Vnne dist. 115.07 pc (375.36 l.y.)

STF 1967 = Gamma CrB: Definite mis-shape, oval to egg.  8" 667x.  [a great catch at 0.22"!]

15h 42m 44.57s +26° 17' 44.3" P.A. 104.6 sep 0.22 mag 4.04,5.60 Sp B9V+A3V dist. 44.78 pc (146.07 l.y.)

lite night

Haven't been able to catch a break, lately.  When the upper atmosphere was clear the marine layer would move in around 9pm and put a lid on any observing.  Last night, though, the layer merely provided poor transparency.  I took out my 8" f/7 to look at Jupiter and the moon.  I actually picked the whole scope up and moved it around the yard to get better views.  Watched the nearly full moon rise over the observatory and some trees.  I also had my binoculars out and use those on the same targets.  A good night but I wish it were clearer.  It is similar weather tonight.  I will spend time getting the 20" ready (fixing the fan, connecting Sky Tools) so it really is ready when the weather finally cooperates.

it was the fan!

I was out only briefly with the 20".  The mirror was well cooled having fans running on it since 5:30pm.  I still had the bar shaped aberration.  For some reason I thought to turn off the fans to see the effect.  At first I turned off the boundary layer fans, no change.  Then I turned off the rear fan, and bingo! clean star images.  The effect was immediate.  I turned the rear fan back on and watched as the bar reformed.

I am very puzzled about this, since I had not made any change to the fan.  It could be the rear light baffle I added is causing a weird air current -- but the boundary layer fan should take care of that, and anyway the aberration is there whether those fans are on or off.  In any case, I will remount the rear fan and see whether that solves the problem, with the baffle on.  Otherwise it's off with the baffle.

Nothing interesting to note other than there was a very bright ISS pass travelling west to south east, which faded post meridian as it finally entered earth's shadow.  It's staying light very late now, so observing time is limited.

aberration

Last night was the first decently clear night in a long time.  I set the 20" to cool at around 5pm and started to observe around 9:30pm.  I thought this would be long enough to take care of any thermal issues, but I was wrong...  I still had the strange bar-like aberration when looking at bright stars and brighter double stars.  Each star would be elongated into a bar with two bright points at the end.

I remembered some of the steps in this article. I rotated my head and the bar didn't change.  I tried inside and outside of focus and the bar stayed in the same direction.  I rotated the primary slightly (maybe only 30 degrees) and it appeared to stay the same.  I loosened the secondary adjustment screws and nudged the mirror itself to make sure it wasn't pinched in the holder, and recollimated, but still no change.  I tried the 8" off axis mask, and while the star images cleaned up and I split it nicely (I was viewing STF 1639 as my test object, 1.85" 6.74/7.83), the image was not crisp and soon the bars reappeared.  I thought perhaps the bar was seeing dependent.

I went to M3, which looked really great with the mask on, better than Big Blue.  I was thinking I would see the aberration with all those stars, but I did not -- it must only show on brighter stars.  With the mask on the sky background was darker.  I removed the mask and the background turned to a milky glow, but at the same time M3 was brighter and more stars resolved in the core and more stars glittered on its perimeter.

Next I tried STF 1785 (2.78" 7.36/8.15) at full aperture and 333x, and the stars showed the aberration: each star seemed to have its own pair with a bright line joining them.  With the mask the bright line was dimmed but it looked like a double-double.  Adding the barlow to this (for 667x) the same bar-bell aberration.

Finally I rotated the primary a full 90 degrees, and the orientation of the aberration changed -- this points to the primary as the source of the error.  I don't think the sling or the cell is causing it.  The aberration was still there but it was smaller.  It makes me think the mirror is unevenly cooled because of the two boundary layer fans blowing across the mirror from the back.  I copied this design from Teeter Telescopes but it seems this is not the right solution.  I will try suspending a fan above the center of the mirror to see if that helps -- I need a trip to the hardware store to find the correct wire.

It's disappointing to have this defect (and a surprise since I didn't see it in the previous two years).  But I'm looking forward to fixing it.  The scope tracked really well and it will be a really satisfying instrument to use.  I also plan to put the Big Blue's Feathertouch focuser on it since last night I felt like I needed it.