Author Topic: Some recent ! and !! doubles, and a question  (Read 440 times)

mccarthymark

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Some recent ! and !! doubles, and a question
« on: October 28, 2017, 01:32:22 PM »
Over the last couple of months I’ve made many dozens of double star observations from my light polluted back yard, with my 12.5 f/7 reflector.  There have been several nights of very good (Pickering 7 to 9) seeing, and I tried going after close and faint pairings.  Of the numerous observations I’ve selected the ones I noted with “!” or “!!”, which denote my excitement on observing the particular pair.  These are fast setting in the west now, but I hope others will have a look.

STF 2606: Hair split to clean split when seeing stills and there is only an airy disk.  Near equal, half a delta mag. 0.8" [Good catch! 0.66"! 1.2" at discovery, so old Wilhelm could see it in his 9-inch]
19H 58M 32.66S +33° 16' 38.8"
P.A. 146.8 SEP 0.66” MAG 7.74/8.43
SP F5IV DIST. 78.43 PC (255.84 L.Y.)

STT 398: B is very faint, appears as a brightening or pin-prick in A's diffraction.  2-3 delta mag, 1"
20H 07M 23.69S +35° 43' 05.9"
P.A. 82 SEP 1” MAG 7.45/9.20
SP B0IV DIST. 628.93 PC (2051.57 L.Y.)

STT 386: Tight near equal, nice, split with seeing, 1"
19H 48M 16.51S +37° 09' 37.5"
P.A. 70 SEP 0.9” MAG 8.52/8.61
SP A1III DIST. 2222.22 PC (7248.88 L.Y.)

BU 155: Clean split, nice disks, 1 delta mag, 1".  Pale yellow and pale Easter egg blue! [AB seen, 4 stars visible.]
20H 51M 05.41S +51° 25' 01.7"
P.A. 38 SEP 0.7” MAG 7.36/8.13
SP A9IV DIST. 124.53 PC (406.22 L.Y.)

AC 17: !! Wow.  Pretty orange-yellow and much fainter 3 delta mag B, resolves into view with seeing, just appears then vanishes if seeing quavers.  ~4".  [AB seen.  5 stars in system.]
20H 12M 31.73S +51° 27' 49.0"
P.A. 83 SEP 4.3” MAG 6.17/10.55
SP K2.5III DIST. 106.16 PC (346.29 L.Y.)

STT 420: ! Light yellow A and reddish B, very faint, very wide, 3 delta mag.
20H 54M 22.25S +40° 42' 10.6"
P.A. 2 SEP 5.5” MAG 6.69/10.50
SP B8VNNE DIST. 248.14 PC (809.43 L.Y.)

STT 419: ! Tough, needed to wait for a while for right seeing.  Bright yellowish A with brightening in diffraction which stays put and recedes to a fine point momentarily with the seeing.
20H 54M 42.00S +37° 04' 25.3"
P.A. 23 SEP 1.6” MAG 7.20/9.97
SP A0 DIST. 193.8 PC (632.18 L.Y.)

Lambda Cyg = STT 413: !! 1.5 delta mag, blue-white.  Bright mess resolves to two disks 0.8-1.0”, with seeing. [AB seen, there are six stars in the system]
20H 47M 24.53S +36° 29' 26.7"
P.A. 359.3 SEP 0.92” MAG 4.73/6.26
SP B5VE DIST. 235.85 PC (769.34 L.Y.)
 
BU 445: !! Orange-red with exceptionally fainter B, only when seeing stills, else it is lost in the diffraction.  Pinpoint.  2”, 4 delta mag.  [AB seen.  There are six stars in the system]
21H 03M 29.53S +29° 05' 33.0"
P.A. 109 SEP 4.8” MAG 7.00/11.14
SP G8III DIST. 197.24 PC (643.4 L.Y.)
 
BU 67: ! Pale blue A and 3 delta mag B, ~2”.  In the middle of the Cygnus Loop.
20H 50M 36.05S +30° 54' 45.7"
P.A. 311 SEP 1.5” MAG 6.85/9.87
SP A8III DIST. 120.05 PC (391.6 L.Y.)
 
Ary 48: !! A beautiful split in finder, just equal pair, wide separation, white with red tint.
20H 37M 45.00S +32° 23' 42.9"
P.A. 41 SEP 53.3” MAG 8.23/8.76
SP F8

STT 408: ! Very fine dull white A and pinpoint B, split well with seeing, ~2”
20H 34M 01.96S +34° 40' 44.4"
P.A. 193 SEP 1.6” MAG 6.75/9.37
SP B7V DIST. 332.23 PC (1083.73 L.Y.)

HO 603: !!  Very wide 2 delta mag, but B has a fainter close pair to it, seen with averted vision, about 3” separation. [AB 7.53/9.82 80.5"; BC 9.82/11.30 3.6"
21H 32M 04.61S +34° 12' 06.1"
P.A. 251 SEP 80.5” MAG 7.53/9.82
SP F0 DIST. 96.9 PC (316.09 L.Y.)

STF 2422: 553x.  !! Very tight, <0.8", equal light orange, pretty faint.
18H 57M 07.83S +26° 05' 45.1"
P.A. 69 SEP 0.8” MAG 7.93/8.25
SP A2IV DIST. 156.25 PC (509.69 L.Y.)

STF 2406: 553x. !! Bright white, 3-4 delta mag, B is averted vision only and delicate, with seeing.  Wow!
18H 49M 55.77S +26° 25' 30.6"
P.A. 5 SEP 4.8” MAG 7.12/11.21
SP A3V DIST. 118.34 PC (386.03 L.Y.)

STF 2358: 553x.  !! Faint near equal <2", another brighter / wider pair nearby.  Nice!
18H 38M 35.04S +30° 43' 20.1"
P.A. 223 SEP 2.5” MAG 9.81/10.19
SP F8

BU 1206: 553x.  !! Very much fainter B, 2", 3-4 delta mag.  Pinpoint when seeing stills.
20H 19M 07.08S +36° 45' 07.6"
P.A. 348 SEP 1.7” MAG 7.53,10.70
SP F4III

WEI 35: 553x.  Double-double!  Ah!  Near equal 3", and closeby a wider pair, 5", 1 delta mag. [AB is first, CD might be second?  4 stars visible in system]
20H 29M 13.54S +37° 30' 45.8"
P.A. 213 SEP 4.1” MAG 8.35/8.81
SP F5 DIST. 305.81 PC (997.55 L.Y.)

STT 403: 553x.  Dramatic near equal white, just split, 1", with a third in the system 2x fainter and wide separation [Indeed a triple, as described.]
20H 14M 21.53S +42° 06' 15.6"
P.A. 172 SEP 0.9” MAG 7.31/7.64
SP B9IV-V DIST. 581.4 PC (1896.53 L.Y.)

UV Cyg = A 598: 553x.  !! Orange-red with fainter blue 1", 1 delta mag.  Seeing must still -- and it does.  A a perfect round disk the color of the setting sun.  Very special.  [AB seen, AC 50" did not notice]
19H 36M 29.82S +41° 24' 08.6"
P.A. 193 SEP 1” MAG 9.91/10.15
SP F5

STF 2496: 553x.  !! Very much fainter B, a pin prick when seeing stills.  3 delta mag, 2" [AB seen, AC super wide sep]
19H 15M 19.18S +50° 04' 16.0"
P.A. 80 SEP 2.1” MAG 6.46/10.00
SP G8III DIST. 134.59 PC (439.03 L.Y.)

ES 1651:   Challenging!  Faint elongated star with direct vision.  With averted vision it flashes a split, half delta mag, just split.
18H 15M 49.67S +41° 06' 37.8"
P.A. 5 SEP 2.4” MAG 11.19/12.36
SP F5V DIST. 225.73 PC (736.33 L.Y.)

STT 365:   Very fine but no mistake, white and blue stars, ~4", 3 delta mag.  Nice! [AB, C seen.  AB is 0.4" and would have shown elongation if the seeing was better and/or I was looking carefully.  AB,D a very wide separation.]
18H 55M 57.14S +44° 13' 41.9"
P.A. 258 SEP 2.7” MAG 6.97/10.52
SP A2 DIST. 186.57 PC (608.59 L.Y.)

BU 641: 553x.  !! Extraordinary!  Moderately bright A and much fainter B, 2 delta mag, <1" separation.  Seeing needs to still.
18H 21M 48.44S +21° 30' 27.9"
P.A. 341 SEP 0.8” MAG 7.03/8.66
SP B9.5II DIST. 264.55 PC (862.96 L.Y.)

STF 2315: 553x.  Near contact / overlapping disks, 0.5 delta mag.  [AB seen: a very good catch considering 0.6" separation.  5 stars in system, faint and far.]
18H 24M 58.46S +27° 23' 41.3"
P.A. 116.2 SEP 0.61” MAG 6.57/7.77
SP A0V+A4V DIST. 117.51 PC (383.32 L.Y.)

=====

My question is about whether faint very close B stars can be noticed as an out of roundness in the A star.  There are a few times (a couple examples below) when I suspect seeing a not round airy disk but I would assume this would only be the case if the B star was near the same brightness as A, to effect the brightness and therefore its shape.  If the B is too faint, say more than 2 delta mag, I think it would probably be too weak an influence and simply be lost in A’s glare.  I’m interested to know of others’ experiences.

47 Cyg: Carbon yellow-orange disk, maybe not round.  Many faint companions. [WRH 34 is AB, 0.3 4.84/7.30.  Not sure it could be seen as out of roundness.  BU 1490 is AC, 115.1" and 4.82/11.87]
20H 33M 54.19S +35° 15' 03.1"
P.A. 278 SEP 0.3” MAG 4.84/7.30
SP K2IB+B3V DIST. 847.46 PC (2764.41 L.Y.)

HO 137: Needs more resolving power.  At 553x some out of roundness to the disk, but not certain.  Used 885x with apodizing mask some lumpiness to dusk but it dances around.  The companion is too faint to show up as out of roundness anyway.
20H 40M 36.26S +29° 48' 19.6"
P.A. 352 SEP 0.7” MAG 6.13/9.26
SP A2V DIST. 74.24 PC (242.17 L.Y.)
« Last Edit: November 01, 2017, 10:22:17 PM by mccarthymark »
Mark

sgottlieb

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Re: Some recent ! and !! doubles, and a question
« Reply #1 on: October 31, 2017, 06:25:43 PM »
I really enjoyed reading your results, Mark!  You've really taken on the challenge of close, unequal doubles.  Great job!!

Are these doubles you ran across using the Interstellarum Deep Sky Atlas or from another source?
« Last Edit: October 31, 2017, 07:41:27 PM by sgottlieb »

mccarthymark

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Re: Some recent ! and !! doubles, and a question
« Reply #2 on: November 01, 2017, 11:06:40 AM »
When observing at home I'm usually looking at doubles, sometimes the moon or planets.  On nights of average seeing, I use the Cambridge Double Star Atlas (2nd edition), which is a good fit for small to medium size scopes -- though there are a fair amount of challenging objects plotted too.

For nights of better seeing, I've been using the Carro Catalog of Double Stars to prepare a target list.  It was created by Joseph Carro, a southern CA observer, and published a few years ago in The Journal of Double Star Observers (www.jdso.org, Vol. 9 No. 3 July 1, 2013, p 203-6).  Carro took the WDS and other sources, created an excel file of pairs with the A star magnitude 12 or brighter, and sorted them by constellation.  When I found the list a couple years ago JDSO had a link to the spreadsheet on its home page, but I don't find it there now.  If anyone wants a copy PM me and I'll email it to you.  I've seen other spreadsheets based on the entire WDS, but without the constellation names they were too time-consuming to use for session planning.

12th mag is about the limit of my 12.5-inch scope from a red-zone location.  To prepare I check if the object is plotted in CDSA; if it isn't then I consider if it is doable, then prepare a finder chart using AAVSO's VSP (https://www.aavso.org/apps/vsp/).  I print those out and sort the pages in a logical star hop sequence, so when I have a good night I get up on the ladder and start searching for each one; often I don't have to come down from the ladder until I have to reset my equatorial platform--there's usually quite a lot of targets to search for.

I'm thinking of getting Nexus DSC which, per the manufacturer, will have all the Struve and ADS catalogs included in the database in their next firmware release.  This would unlock many more targets.

** edit: corrected URL & some grammar; thanks Dave
« Last Edit: November 01, 2017, 10:19:37 PM by mccarthymark »
Mark

Dave Ittner

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Re: Some recent ! and !! doubles, and a question
« Reply #3 on: November 01, 2017, 04:12:06 PM »
Let me know when you get your encoders installed (if you can - get the 311K tic ones) and I will loan you my Nexus DSC.
It really is made for visual observers. Serge has a ton of catalogs installed that cover all of the faint fuzzies.

Dave Ittner

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Re: Some recent ! and !! doubles, and a question
« Reply #4 on: November 01, 2017, 04:14:16 PM »
and by the way, he meant to type www.jdso.org