41 replies to this topic

[Fiske]

Phil Harrington's Binocular Universe column in the September issue of Astronomy magazine, titled "Searching for the Cygni 100," discusses the Cygni 100 observing challenge initiated in this forum a year ago. 

 

The link to the StelleDoppie list included in Phil's column is for a revised version of the original list, with changes to better suit 20x binoculars. A Sky Safari skylist of the updated version is attached below. It includes 93 items (because seven of the items are multiple pairs).

 

Phil's column also mentions the Cygni Sweet 16, a highlight list of sixteen doubles selected from the full 100. Here is a StelleDoppie list of the 16.

 

 

I have decided to re-observe the entire list and welcome observations from others who would like to join the fun. 

Attached Files

•  Cygni 100 v2.skylist   24.25KB   86 downloads

Edited by Fiske, 23 July 2023 - 06:19 PM.

[jrazz]

I'm in!

 

That list was fun and I want to redo it with the 34x80.

[Fiske]

I'm in!

 

That list was fun and I want to redo it with the 34x80.

Yay!

 

[Fiske]

Here is a nice group of four double stars from the Cygni 100, in a star field which also includes a fine planetary nebula (NGC 6826, the Blinking Planetary Nebula) and an interesting red giant Mira-type variable star, R Cygni, that has a magnitude range of 6.1 to 14.4 in a 426.5 day period. The field is near the western wingtip of Cygnus.

 

 

 

I made the following observations on Wednesday 26 July 2023 from my suburban driveway, with a naked eye limiting magnitude of about 4.5 at the zenith, and an SQM-L meter reading of 18.07-18.11 mpsas. The moon was 51% illuminated, an 8-day moon, but was well to the south and screened by the roof of my house and trees south of my yard.

 

STTA 182 AB / V2080 Cygni
19 26 48 +50 08 44
7.46/8.58 sep 73.3" pa 297*

 

Yellow primary, light blue secondary. Generously spaced. Primary obviously brighter. At the beginning of a sinuous rill of stars which leads to STF 2486.

 

STF 2486 / HR 7294
19h12m +49*51'
6.54/6.67 sep 7.14" pa 203.4*
Physical double star
Distance: 79.76 LY
Spectral type: G2V/G3V

 

Just resolved with the 18x70. Evenly matched, brilliant white stars separated by a hair. This double is not in the v2(v3) list, but I might add it back into my final list. It is a terrific DS.

 

STFA 46 / 16 Cygni
19 41 49 +50 31 32
6.0/6.23 sep 39.7" pa 133*
Physical double star
Distance: 68.76 LY
Spectral type: G3V / G1.5Vb

 

Brilliant gloss white stars at an easy distance. One of the finest double stars in Cygnus. in a fantastic star field with NGC 6826 the Blinking Planetary Nebula and other luminaries in the swan's western wingtip.

 

H 5 47 / e Cygni / 26 Cygni
20 01 22 +50 06 17
5.17/8.94 sep 41.8" pa 150*

 

Brilliant yellow primary with a tiny grayish-tan companion hovering near its side. A pleasing 18x double.

 

Here is an annotated simbad image of part of the field.

 

 

R Cygni

 

Based on the AAVSO information I just reviewed, R Cygni is probably toward the fainter end of its range and not visible with binoculars from my yard at this point. I plan to revisit the star field soon to confirm that.

 

NGC 6826 / Blinking Planetary Nebula

 

Oddly similar to the Eskimo Nebula star field in that the planetary is adjacent to a distinct circular arc of stars. I viewed it with the 120XL-SD+20XWs (33.5x), and it honestly deserves more magnification. But it could still be seen as a planetary at 33.5x, with a distinct (small) envelope around a central star. The blinking effect was slightly visible as well, switching between direct and averted vision. With the 18x70, it had that slightly odd, soft look that planetaries sometimes have. The color was not distinctive as with the Cat's Eye Nebula in Draco, but it still had that not quite stellar thing about about it. Not as pointy as a star should be.

Edited by Fiske, 29 July 2023 - 10:44 AM.

[jrazz]

Completely spaced on this last night... Star struck by some random eyepieces...

 

I put these as visible on my SkySafari so hopefully make some progress on it tonight!

Since I'm using the MoonStar as a finder I should be able to cruise through this even faster this time around!

[Dale Smith]

Great report, Fiske! The skies have not been great here lately, but I want to go for some of these when they clear.

[Fiske]

Completely spaced on this last night... Star struck by some random eyepieces...

 

I put these as visible on my SkySafari so hopefully make some progress on it tonight!

Since I'm using the MoonStar as a finder I should be able to cruise through this even faster this time around!

You left me in the (star) dust the last time around, Jordan. 

[Fiske]

Great report, Fiske! The skies have not been great here lately, but I want to go for some of these when they clear.

Looking forward to your observations, Dale. 

[Fiske]

I had a long observing session Friday evening, which included some Cygni 100 observations in the northern area of the constellation. Eta and Theta Cephei provided a helpful celestial navigation beacon as shown in this Sky Safari chart.

 

 

 

STTA 194 / HR 7611
19 53 35 +59 42 31
6.06/9.11 sep 67.8" pa 354*

 

Brilliant white primary with faint white companion at an easy distance. At one end of an arc formed by four brighter stars.

 

STF 2687
20h26m +56*38'
6.37/8.31 sep 25.1" pa 118*
Nature uncertain
Distance: 616.65 LY
Spectral Class: B9V / A2V

 

White primary with a neon blue companion at a comfortable but cozy distance. Primary significantly brighter. At one tip of a pleasing "V" asterism, slightly reminiscent of the Hyades. An excellent 18x double in a pleasing field. Just resolved with mounted 10x50 binoculars (Fujinon). Could not resolve with hand held Canon 10x42L (because the primary is too faint for this instrument in urban skies).

 

FRK 9
20h26m +54*01'
8.44/9.04 59.8" pa 238*

 

Yellow primary with white secondary at a comfortable distance. Primary brighter. In a busy field near STF 2681.

 

STF 2681
20h22m +53*25'
AC 7.97/8.89 38.2" pa 199*

 

Nikon 1870: Both stars white. Primary slightly brighter. Flanked by brighter field stars. Separation is less than FRK 9.

 

BU 426AC
20h02m +54*39'
8.53/8.39 163.2" pa 53*

 

BU 427CD
20h02m +54*39'
8.39/10.18 3.1" pa 336*

 

ENG 68CE
20h02m +54*39'
8.39/8.92 160.3" pa 158*

 

The Cygni 100 doubles are BU 426 and ENG 68. But the latter is not listed in Sky Safari and BU 427 (which shares the same C component with ENG 68) is listed.

 

A triangular group of three stars, equally bright. All three warm white. Adding interest to the group, two of the three stars forming the triangle have close 10th magnitude companions, which I resolved with the 120XL-SD+12.5mm Morpheus eyepieces ( 53.60x / 1.46* FOV) – BU 426 AB 8.4/10.5 sep 5.9" pa 307*; BU 427 CD 8.39/10.18 sep 3.1" pa 336*.

 

Edited by Fiske, 06 August 2023 - 02:44 PM.

[jrazz]

I'm off to a really slow start this year... Clouds, rain, back pain, lack of sleep all conspire to limit my observing time.

 

I have made a promise to myself to complete this renewed challenge using the APM 34x80 which is definitely looking like fun. Last year it was the 20x65 and navigating was challenging, this year it's somehow easier with the addition of the MoonStar as finder. The only problem is that I spend more time looking at the wonderful nebulae and large scale structures (clusters and such) using the MS rather than looking for the doubles!

 

I know, rough problem to have

[Fiske]

More of a marathon than a sprint, Jordan. 

 

Or a leisurely celestial stroll, perhaps? You set star hopping speed records on the Cygni 100 last year. 

 

Looking forward to your reports! 

[Christine_Z]

Just an FYI, I don't know if this bug is MacOS only, but a generated legacy .skylist for SkySafari like the one shared above will crash SS UNLESS you edit the .skylist file in a text editor.

 

You have to change the ObjectID to 2,-1,-1

 

Now this could be a pain, unless you feel comfortable using wild card replacements in the file, as these observing lists can be long and it's difficult to do a simple find and replace since each legacy file has individual ObjectID parameters.

However, Stelledopie will generate this type of ObjectID identifier automatically now, so it shouldn't be an issue, however older files that have been shared may generate the crash.  This has no effect on the proper information being tagged and displayed by SkySafari (I am using SS6 Pro on MacOS X)

 

Example included 

 

SkySafariObservingListVersion=3.0
SortedBy=Default Order
SkyObject=BeginObject
ObjectID=2,-1,-1
CatalogNumber=9 Cas
CatalogNumber=HR 9100
CatalogNumber=HD 225180
CatalogNumber=SAO 10954
CatalogNumber=BD +61 2586
CatalogNumber=HIP 330
CatalogNumber=H 5  79
CatalogNumber=WDS 00042+6217
CatalogNumber=TYC 4018-3891-1
DefaultIndex=0
StelleDoppieID=265

[Fiske]

Interesting. Thx, CZ! 

 

 

I'm using SS 7 pro on Android and there are no issues with it.

Edited by Fiske, 08 August 2023 - 05:30 PM.

[Christine_Z]

Interesting. Thx, CZ! 

 

 

I'm using SS 7 pro on Android and there are no issues with it.

I use SS6P on my iPhone & Desktop. (there is no reason to update, as the two are identical in features, except for a different user interface.)

 

There is no SS7 version for the desktop, yet. But this has been a known issue for years, and SimCur has not fixed it. 

 

The lists auto populate from the desktop to the phone. Not sure that a .skylist can even be imported with an iPhone ???

 

For those suffering from the bug, I would suggest just using stelledopie to generate your observing lists.

Edited by Christine_Z, 08 August 2023 - 06:16 PM.

[Fiske]

 

I created the skylist in Stelladoppie, but then exported it from SkySafari. That's what messed it up. Thanks for this, CZ. 

[Fiske]

Friday night was to be an ASKC club star party, but it was rescheduled for next Friday because thunderstorms were in the forecast and the weather was to be hot and humid. The night turned off clear, BUT it was 90 degrees at 10 pm and still in the 80s at midnight. No way I'm observing in weather like that without electric fan life support, shown here at full blast about three feet from my observing position.  (Along with my trusty Nikon 18x70 on the Farpoint p-gram and the 82XL-SD on an OB 5000 mount.) Throughout the observing session, lightning from the south lit up the sky even though my view was entirely clear.

 

 

I've decided to write a Cygni 100 Observing Guide. It's surprisingly difficult to come up with a manageable format, but after trying various options I have settled on an approach that should work for the catalog portion of the guide. I opted to organize the catalog alphabetically by discoverer code (aka WDS name), otherwise it's difficult to keep track of the entries and cross-reference them. All Cygni 100 doubles are assigned a sequential number based on the name order. (I spent days trying to organize them based on adjacent position and finally gave THAT up.  ) The data is from a combination of StelleDoppie, SIMBAD, and VizieR catalogs.

 

Here are some observations made on a hot and humid Kansas night. 

 

STF 2743 / f1 (59) Cygni / C100.072
20h59m +47*31'
4.74/9.43 sep 21.0" pa 353*
Nature uncertain
Distance: ?? / 1240.56 (2020 cat.) LY
Spectral Type: B1.5Vnne / A3V
Color Index: -0.04 blue-white / ??

 

 

Nikon 18x70 / Friday 11 August 2023 / urban sky
Extremely difficult to resolve with the 18x70. I had to locate it first with the 82XL+14XWs (32.14x) to see it with the 18x70. The primary is brilliant white. The secondary is a gray pip at its side. Spectacular field. f2 Cygni to the east is deep yellow.

 

f1 / 59 Cygni is categorized as a classical "Be" star, a non-supergiant blue star showing one or more Balmer series emission lines. https://en.wikipedia.org/wiki/Be_star

 

STTA 215 / HR 8107 / C100.96
21h10m +47*41'
AC 6.55/7.52 sep 136.7" pa 189*
Non-physical
Distance: 2407.41 / 1107.98 LY
Spectral Type: B6IV / M5III
Color Index: -0.02 blue-white / +1.39 orange-red

 

Nikon 18x70 / Friday 11 August 2023 / urban sky

Light blue primary with apricot secondary at a generous distance. Both stars bright, but the primary is brighter. A pleasing spectacle. Should be easy with mounted 10x50 binoculars.

 

BU1138 / HR 8064 / C100.020
21h02m +45*50'
AC 6.46/7.82 sep 152.1" pa 330*
Non-physical
Distance: 1309.6 / 63.46 LY
Spectral Type: B3Vn / K2.5V
Color Index: -0.132 blue-white / +0.98 yellow-orange

 

Nikon 18x70 / Friday 11 August 2023 / urban sky

White primary with dusky yellow secondary at a generous distance. Primary brighter. Near 60 Cygni. In a spectacular field. Should be easy with mounted 10x50 binoculars.

 

And so here is a question for indefatigable 20x80 observers (or anyone else who wants to play). 

 

STF 2743, with a magnitude difference of 4.69 (4.74/9.43) and a separation of only 21" is an extremely challenging 20x double. I'm inclined to keep it in the catalog to encourage observers to push the 20x binocular double star envelope. Care to give it a try and share your observations here? 

Edited by Fiske, 14 August 2023 - 12:14 AM.

[SStoffer]

I have had two occasions in the past several years where observing at the Veen Observatory under clear skies were interuppted by nearby lightning from thunderstorms. Very interesting especially considering the first instance the storms were clear across to the east border of the state of Michigan near Detroit. 

 

I need to get a pair of 20X binoculars to do these double stars. Well...let's start lookinmg. 

[Fiske]

I have had two occasions in the past several years where observing at the Veen Observatory under clear skies were interuppted by nearby lightning from thunderstorms. Very interesting especially considering the first instance the storms were clear across to the east border of the state of Michigan near Detroit. 

 

I need to get a pair of 20X binoculars to do these double stars. Well...let's start lookinmg. 

Oberwerk 20x70 ED Ultra 

[columbidae]

I brought out the binos and started speedrunning the list last night, and had a couple questions:

 

 

Has anyone managed to visually distinguish between STF 2538 C and D?  AC and AD are listed separately, but their nearly identical values for separation and PA put the secondaries awfully close together.  STF 2624 AB and BC run into the same problem, in that A and B are too close (2 arcseconds) for there to be a difference between the listings.

 

SHJ 314, 315, 316, and ES 25 all seem to share stars - is this really just a minimally sized open cluster? 

 

Otherwise, it's been a blast - for starhopping's sake it would be nice to find a way to group doubles together by vicinity (with a detailed identification map for those crowded areas).  I definitely did a couple of short detours to a few open clusters - maybe an annex including nearby binocular DSOs and asterisms is in order.

[Fiske]

Wonderful follow up, Columbidae. 

 

  

 

I recently removed STF 2822 BD from the list, leaving AD, because I found that the AB pair has a 1.6" separation, so the B star cannot be resolved with 20x binoculars. Ironically, the AB pair is a physical double star where the AD pair is only optical.

 

I will check the additional pairs you list. In fact, need to check all of the multiple listings for a single double star designation.

 

I am working on a Cygni 100 Guide to be shared in PDF format. There is a lot to do on that.  But my plan is to include some sequence hops with charts for complicated star fields. I have tried to think of a way to organize the list by suggested observing order and just find that to be too arbitrary and complicated. That gave me fits trying to organize the full list, so I have decided to alphabetize the catalog itself by discoverer code, providing various appendixes.

 

And yes, I do think some of the multiple "double star" systems are in reality open clusters. Providing some additional details on that is part of my plan.

 

BU 442 is one of my favorite 20x "doubles" in the list. Only the BC pair qualifies though. Look at this StelleDoppie listing for BU 442. 

 

 

The cluster is explicitly catalogued as IC 4996. What is the point of all the double star pair designations? I'm sure there is a story behind that, just haven't dug into the details yet.

 

A few of the Cygni 100 doubles actually occur in the open clusters M 29 and M 39, the M 39 double ARN 78 AB is particularly nice.

 

Here is another favorite starfield of mine from the list, which features BUP 196 and the open cluster NGC 6819.

 

 

TThe cluster can be glimpsed in averted vision with 20x binoculars in urban skies. And is pleasing with BTs in urban skies and can be resolved with BTs from darker sites. Honestly, this is an OC where a larger reflector from a darker site would provide the ideal view.  Still a lot of fun with binoculars and BTs.

 

Noting asterisms, open clusters, and deep sky objects that can be seen in the same star fields with Cygni 100 doubles is in the spirit of the project. I plan to incorporate some of those into the guide, probably in detailed star field guides for selected doubles. You see how the Cygni 100 Guide project grows and grows?  In IT we call this scope creep. (Which might be thought of as a double entendre.  )

 

Naturally the guide is going to include a section on double star discoverer codes. BUP stars, for example, are Burnham Proper Motion stars. I am planning an excursion to Linda Hall Library to have a look at Measures of Proper Motion Stars Made with the 40-inch Refractor of the Yerkes Observatory in the Years 1907 to 1912 (by S. W. Burnham -- published by the Carnegie Institution of Washington 1913), which is included in their collection. Linda Hall is a nationally renowned technical science library in the KC area, with a fabulous history of science collection.

Edited by Fiske, 27 August 2023 - 08:58 AM.

[jrazz]

...

 

I recently removed STF 2822 BD from the list, leaving AD, because I found that the AB pair has a 1.6" separation, so the B star cannot be resolved with binoculars. Ironically, the AB pair is a physical double star where the AD pair is only optical.

...

Booo...

 

And false!

 

Split with a binocular....

 

Binocular Telescope: BT-100XL/SD+4mm TOE.

[Fiske]

Booo...

 

And false!

 

Split with a binocular....

 

Binocular Telescope: BT-100XL/SD+4mm TOE.

  

 

But not appropriate for the 20x80 guideline for the Cygni 100. 

 

(Note edit to the post in question to silence querulous sniping from a certain BT Super Hero.  )

Edited by Fiske, 27 August 2023 - 09:00 AM.

[columbidae]

Got through another chunk of the list, despite the blazingly bright moon.  I turned my binoculars to it at the end, but trying to look at it felt like looking at the sun.

 

A few notables:

 

STF 2743 AB (59 Cyg), mags 4.7, 9.4 @ 21", 353 deg.   The magnitude difference really makes this one a standout.  Almost makes it feel like a "binocular Rigel", though even Rigel itself might be doable in something larger than a 20x. 

 

BU 839 AC, mags 8.5, 9.0 @ 22.5", 200 deg.  The secondary seemed dimmer than the listed 9.0 mag to me, or at the very least, the magnitude difference sure didn't seem like only 0.5.  Maybe someone could double check this one and prove me crazy.

 

STF 2707, mags 7.9, 8.6, 9.4 @ 22", 29 deg and 55", 195 deg.  This nicely balanced triple reminds me a little bit of Beta Monocerotis, but diminished by the wider relative spacing and dimmer components.  With a slightly larger aperture (or just less full moon in the sky), this ought to pop out nicely.

 

STF 2758 (61 Cyg), mags 5.4, 6.1 @ 32", 154 deg.  It's just really nice to look at, honestly.

 

H 113 AB, mags 6.6, 9.5 @ 19", 299 deg.  Magnitude difference, close separation, and a dim secondary make for (relatively) tough double.  Makes it satisfying for everything to click and to see the secondary come into view.

 

--------------------------------

 

These two are not on the Cygni 100 list, but I stumbled on them anyway:

 

STF 2832 AB, mags 7.8, 8.3 @ 13.2", 213 deg.  A close pair, still neatly separated at 20x, about a degree NNE of ARG 43.  A small pair of eyes peering down.

 

STF 2789 AB, mags 7.7, 7.9 @ 6.9", 113 deg.  A very close pair, and even.  I wasn't able to get a clear split on this one - more than elongation, with hints of a notch breaking open and closing (depending on my head movement).  Sort of like a stellar peanut.  Maybe taking some time to "try-hard" a little on this one would split it confidently.   It would be a total shame if anyone with a 34x80 or BT cracked it wide open all willy nilly.  According to the data in Stelle Doppie, the secondary takes 18,000 years to complete an orbit around the primary, so I wouldn't hold my breath waiting for a more favorable separation.

[Fiske]

A fine report, Columbidae. Well done! 

 

It looks to me like the magnitude listing for BU 839AC in the WDS is incorrect, which has been known to happen. I'll send an email to the USNO about it, and they may update the listing based on Tycho-2 catalog data available through simbad. The visual magnitude looks to be 10.05, which is consistent with your observation. That double will be removed from the list and replaced with something else.

 

The separation parameter for the stelledoppie query was minimum 15-arc seconds, which was maybe on the conservative side for 20x doubles, so additional pairs, like the STF 2832AB pair you observed is a likely addition in it's place.  In fact, thinking about it, I'm going to replace BU 839 with STF 2832AB and give you credit for it in the catalog notes. 

[Fiske]

Here is an observation of STF 2707 from earlier this August. The image includes STF 2707, ES 89 (not a Cygni 100 double), and V Cygni, a variable star with a magnitude range from 7.7-13.9 over a 421.3 day period which I have been meaning to take a peek at. 

 

 

STF 2707
20h37m +47*56'
AB 7.94/9.45 sep 21.8" pa 29*
AC 7.94/8.62 sep 55.317" pa 194.7*
Non-physical
Distance: 976.63 / 9898.52 / 986.41 LY
Spectral Type: A0 / ?? / B8
Color Index: -0.01 blue-white / +0.74 yellow / +0.03 white

 

STF 2707 is a pleasing triple for 20x80 binoculars. The wider C component is immediately seen but the shy B component is slower to reveal itself. The A and C stars are white, the B star is sand-colored (tan with the 82XL+10XWs / 45x). The B star is an astonishing 9,898.52 light years distant according to the Gaia Early Data Release 3 catalog (2020). So it's more than 10x the distance of the A star. The C star, on the other hand, is nearly at the same distance, at least within a reasonable margin of error, but the A/C pair is moving in different directions, so not in orbit. I have a log entry for STF 2707 from Wednesday 17 August 2022 and then re-observed it last Wednesday night (9 August 2023).