26 replies to this topic

[Fiske]

I happened upon the double star 41 Draconis by accident last week while wandering in the northern reaches of Cepheus and then crossing over into Draco. An area of the sky I haven't spent that much time exploring. First sighting was with an Oberwerk 100XL-SD. I didn't identify the star until later, looking over charts and consulting SkySafari. Here is my journal entry (from Thursday 23 September 2021) -- also included in this post on the "What did you see last night..." topic here in the bino forum.

 

STF 2308 / 41 Draconis
18h00m +80*00' / SA2K: 3 / UM2K: 3
5.70/6.0 18.77" pa 231.8*
This was the nicest surprise of the evening. I first saw it with the 100XL+20XW. A remarkable binocular double. The magnitude difference can be seen but is subtle. Both stars brilliant white, though the primary is slightly warmer in tone. Wonderful with the 16x70 too, close but fully resolved. The SkySafari notes are somewhat misleading – the stars are described as cream white when to my eyes they seemed bluish. Different takes on DS colors are common, of course. But the notes also say the stars are "perhaps too close for all but the largest binoculars" though they are easily resolved with the 16x70 (on a night of quite bad seeing) and could probably be seen as two stars in contact with a 12x50. I haven't made that observation yet but will add it to my observing plan.

 

I followed up this evening, making observations with an APM 20x80 ED MS which somehow showed up on my doorstep today (binoholism still running rampant, I'm afraid), an APM 12x50 ED MS, and a Fujinon 10x50 FMTR-SX. All instruments were mounted (in turn) on my Oberwerk PM1 p-gram mount. Easy in the 20x80, as expected (a suburb binocular), but I was able to resolve it in both the 12x and 10x50 binoculars, which was something of a surprise. Both stars were extremely close, nearly in contact, but could still be seen as two stars even at 10x. So, clearly not too close for all but the largest binoculars. I guess claims are sometimes based more on expectations than actual observations? Certainly it would seem so in this case. 

 

I haven't found 41 Draconis listed in any of my binocular guides -- at least five in the bookcase near my chair. But it is nevertheless a pleasing and fun binocular double. I am guessing it can be resolved with a Canon 10x42L IS hand held, but other than IS instruments would probably require a mount for lower magnification binoculars. It might possibly be glimpsed with a 16x70 or 20x80 hand held? 

 

41 Draconis is about 13 degrees due north of NGC 6543, the famous Cat's Eye planetary nebula in Draco, almost precisely on the intersection of 18 hours right ascension and 80 degrees declination.

 

Care to take the 41 Draconis challenge? 

 

Fiske

Edited by Fiske, 28 September 2021 - 11:23 PM.

[Patowl]

Hi, thanks for reporting this observation. Never saw that 41Dra and I will take the challenge for sure.
Reminds me of 20 Geminorum, at sep=19.9" with same components mag, which is an "easy" split with my tripod fixed 10x50.
One difficult challenge to look for is 100 Herculis, with a 14" sep, this one I have been barely able to distinct two close components not well separated but definitely non stellar, still fixed 10x50.
Clear skies!

[Fiske]

Pat,

 

thanks so much for suggesting 100 Herculis. I have observed it many times with telescopes, sketched it years ago for the Astronomical League Double Star program (5 July 2002), and have observed it with the 82XL for sure. But not with smaller binoculars. Moreover, I'm not finding any recent log entries for it, which is just laziness on my part because I have viewed it multiple times over the past 6 months. SO, if I can get an angle on it from my yard (through the western trees) or manage to visit a dark sky site while it is still high enough in the west, I'll definitely try it with some smaller binoculars.

 

Looking forward to your report on 41 Draconis. 

 

Fiske

[Fiske]

Incidentally, I did find an observation of 41 Draconis in a binocular catalog -- Ted Aranda's 3,000 Deep-Sky Objects -- the opening entry for his 18-24 Hours: Summer section. With a 12x35 binocular Aranda rates it as extremely close. At 42x60 "A moderately close equal pair. A nice double." With his remarkable 10-inch Cassegrain binocular telescope, 170x250, "A slightly wide equal pair. Both soft white."

[Patowl]

So I went to observe 41 Draconis last night.
Thank you so much for bringing attention on this one as it is truly a magnificent binocular double.
Used my 10x50 AE mounted on a tripod.
Had to put 41 perfectly in the center of the field, touch nothing and hold my breath...and it is a very close but well separated pair. Both components of the same color, one being slightly more bright.
Thank you again! Clear skies

[Fiske]

Well done, Pat! 

[Fiske]

Here are two challenging doubles for 10 and 12x instruments in Delphinus. The splendid Gamma Delphinus, a renowned double star with a separation at present of 8.86" according to stelledoppie, is too close for smaller binoculars, though a great double for binocular telescopes and telescopes. So try these with your 10 or 12x instruments instead. I observed them Thursday night 30 September 2021.

 

SA2K == Sky Atlas 200 / UM2K == Uranometria 2000

 

STF 2703 Delphinus
20h36m +14*44' / SA2K: 16; UM2K: 84
AB 8.35/8.42 25.1" pa 290*
AC 8.35/8.76 77.8" pa 234*
A lovely triple with the 82XL and 14mm XWs. Need to try it with other instruments. Might be resolvable with 10x and 12x50 binoculars. The AC components certainly, but possibly the AB components as well.

 

STF 2690 Delphinus
20h31m +11*16' / SA2K: 16; UM2k: 84
AB 7.12/7.39 17.8" pa 255*
I also observed this on August 4 with the OB 15x70. Noted both stars white. Beautiful with the 82XL+14XW. Barely resolved with the APM 12x50 ED MS. Seen as two stars in contact with the Fuji 10x50.

 

Edited by Fiske, 02 October 2021 - 11:34 PM.

[scottmm2012]

I observed 40/41 Dra on 2 August at 2300 EST, also for the AL Binocular double program.  My glass of choice for this program is the Eagle Optics Atlas 10x50.  I was fortunate to grab a pair before they were going out of business.  As depicted in my notes, 41 Dra was discerned naked eye with averted vision in my bortle 2/3 sky about 5° south east of Epsilon Umi.  Both appeared similar mag blue white and easily resolved with 10 x 50s on a modified Orion parallelogram mount. 
 

[Trapezium]

Here are two challenging doubles for 10 and 12x instruments in Delphinus. The splendid Gamma Delphinus, a renowned double star with a separation at present of 8.86" according to stelledoppie, is too close for smaller binoculars, though a great double for binocular telescopes and telescopes. So try these with your 10 or 12x instruments instead. I observed them Thursday night 30 September 2021.

 

SA2K == Sky Atlas 200 / UM2K == Uranometria 2000

 

STF 2703 Delphinus
20h36m +14*44' / SA2K: 16; UM2K: 84
AB 8.35/8.42 25.1" pa 290*
AC 8.35/8.76 77.8" pa 234*
A lovely triple with the 82XL and 14mm XWs. Need to try it with other instruments. Might be resolvable with 10x and 12x50 binoculars. The AC components certainly, but possibly the AB components as well.

 

STF 2690 Delphinus
20h31m +11*16' / SA2K: 16; UM2k: 84
AB 7.12/7.39 17.8" pa 255*
I also observed this on August 4 with the OB 15x70. Noted both stars white. Beautiful with the 82XL+14XW. Barely resolved with the APM 12x50 ED MS. Seen as two stars in contact with the Fuji 10x50.

 

I was able observe Gamma Delphinus, STF 2703 and STF 2690 last night with good transparency/seeing, splitting all of them easily with my Obie 100XL BT at 40X. The latter two doubles looked like car headlights coming from afar. The Gamma Del stars were beautifully yellow at different degrees of brightness. Swinging the BT to the left, I compared M2 to M15, with M2 appearing to me the larger and more intense of the two. M31 and M32 were easily spotted, but no joy with M110. In Cassiopeia NGC 7789 was very faintly discernible; NGC 225 (the sailboat cluster) was observed. Perseus was gorgeous: the Double Cluster and Stock 2 bright and sparkling. All in all a beautiful night from my patio. Thanks for the interesting DS targets!

[clastro8*]

Despite peek-a-boo clouds and hungry mosquitoes I was able to attend the Draconis 41 party last evening, thank you very kindly for the invite, Fiske!

 

A few days earlier, I had thought I observed it but couldn't make the PA work out and the double (which I thought I saw) was a bit higher SE of Epsilon than I expected.  Then clouds moved in, forcing patience to have another go at it.

 

But last night I had a good view with 15 x 70 and very much enjoyed the configuration.  I can't say much about the colorings and realize I probably don't have enough experience for that at this point, but does not detract from the overall enjoyment.

 

I was facing north to make this observation and to sketch it, I would have put N at the top with E to the right.  scottman2012's sketch doesn't do it that way, is his a convention, or is it up to the user?

 

Also, he notes a Transparency rating of 7, very high.   I think ratings like that would be very helpful in this forum but haven't seen them before, only an occasional Bortle rating.

 

I'm hoping Fiske will offer further challenges, if there is enough interest, perhaps a separate thread for each one, in order to make follow-ups easier.

[scottmm2012]

 

I was facing north to make this observation and to sketch it, I would have put N at the top with E to the right.  scottman2012's sketch doesn't do it that way, is his a convention, or is it up to the user?

 

Also, he notes a Transparency rating of 7, very high.   I think ratings like that would be very helpful in this forum but haven't seen them before, only an occasional Bortle rating.

 

I'm hoping Fiske will offer further challenges, if there is enough interest, perhaps a separate thread for each one, in order to make follow-ups easier.

My drawing depicts as seen through the binocular at the most comfortable view from my zero G chair.  Transparency and seeing scores are based off the requirement for the AL Binocular Double Star program.  Yes, scored very high, no need to be jealous.  

[Fiske]

Despite peek-a-boo clouds and hungry mosquitoes I was able to attend the Draconis 41 party last evening, thank you very kindly for the invite, Fiske!

 

A few days earlier, I had thought I observed it but couldn't make the PA work out and the double (which I thought I saw) was a bit higher SE of Epsilon than I expected.  Then clouds moved in, forcing patience to have another go at it.

 

But last night I had a good view with 15 x 70 and very much enjoyed the configuration.  I can't say much about the colorings and realize I probably don't have enough experience for that at this point, but does not detract from the overall enjoyment.

 

I was facing north to make this observation and to sketch it, I would have put N at the top with E to the right.  scottman2012's sketch doesn't do it that way, is his a convention, or is it up to the user?

 

Also, he notes a Transparency rating of 7, very high.   I think ratings like that would be very helpful in this forum but haven't seen them before, only an occasional Bortle rating.

 

I'm hoping Fiske will offer further challenges, if there is enough interest, perhaps a separate thread for each one, in order to make follow-ups easier.

There are going to be further observation suggestions, plus more detailed responses to replies that have already been made. Still in my working day, so more later. 

 

My drawing depicts as seen through the binocular at the most comfortable view from my zero G chair.  Transparency and seeing scores are based off the requirement for the AL Binocular Double Star program.  Yes, scored very high, no need to be jealous.  

  

 

My typical approach for sketching doubles is to sketch the eyepiece(s) view and then indicate the west point determined by star drift, which is harder to do with a lower power wide field binocular view.

 

I sketched all of the Astro League double star program doubles years ago. Still have them grouped together in a notebook. That was a lot of fun.

 

Fiske

[Fiske]

Sunday evening, 3 October 2021, I observed with a friend from Lewis-Young park in Louisburg, Kansas, location of the ASKC observatory.  It was a fine evening, despite copious amount of dew and not very steady skies. 

 

I somehow confused 100 Herculis, mentioned by patowl above as a challenge to see as two stars in contact with 10x or 12x binoculars, with Alpha Herculis, actually 64 Hercules and had a look with the Fuji 10x50 and APM 12x50 binoculars.  Needless to say at 4.6" separation, I had no hope seeing anything other than the primary star. I did resolve it with the 100XL-SD+7XW eyepies (80x). An enjoyable though not outstanding view due to the poor seeing conditions.

 

Here are the details for 100 Herculis, which I have reviewed more carefully and added to my observing plan. 

 

SA2K == Sky Atlas 2000 / UM2K == Uranometria 2000

 

STF 2280 / 100 Herculis
18h07m +26*06' / SA2K: 8; UM2K: 67
5.81/5.84 14.3" pa 183*

 

In Delphinus I was able to resolve all three components of the STF 2703 with the Fuji 10x50, which is a fine and fun object in such a small glass. All three stars white. A nice challenge but doable and pleasing. To my surprise, I was also able to resolve STF 2690 with the 10x50. At only 17.8" separation it is closer than what I would have thought observable at 10x, but seeing is believing I suppose. Again both stars white, just barely separated.

 

Here is a chart showing 31/35/41 Draconis, which lie in a fairly straight line. I had not realized it previously, but 41 Dra is relatively easy to locate from the first star of the handle in the Little Dipper, as indicated by the green line in the chart.

 

31 Dra / Psi 1 Draconis / STF 2241

17h41m +72*08'

4.57/5.59 29.6" pa 17.2*

A wider and brighter version of 41, and another excellent binocular double star. 

 

35 Draconis

Not technically a double, but nevertheless a nice binocular pair with nearby HD163767, a 7.53 magnitude star 5'18.5" in pa 318.7*, according to SkySafari data 233 ly distant from 35 Dra, which is 104 ly from our own solar system.

 

[clastro8*]

Thanks, Fiske.  I think there is a forecast of clouds the next few days, but I will look for those on next chance.

 

In July, I believe you had a thread positing Draco 75; I was skeptical from recent failures, but then pleasantly surprised seeing it with the 15 x 70, but couldn't see it with 7x.   

 

I think it is about 6 deg NE of 41 and should add to the fun in this part of the sky.  My notes say it is RA 20 28 14, Dec 81 25 22, Sep 197, PA 283, 5.5/6.7.

Edited by clastro8*, 05 October 2021 - 10:28 PM.

[scottmm2012]

Took a shot at 41 Dra with a pair of Tasco International 440 7x50.  Unable to resolve handheld no matter how hard I tried to brace, I ended up makeshift mounting on a tripod and I was able to resolve the double, just for giggles threw a pair of Sunset 7x35 JB77 and was still able to resolve.  Although, I was unable to resolve handheld but it does amaze me how good the glass is in these vintage binoculars and what you can see when mounted.  Ended running up the Milkyway from Sagittarius hitting all the known fuzzies finishing up on NGC 7000. 

[Fiske]

Thanks, Fiske.  I think there is a forecast of clouds the next few days, but I will look for those on next chance.

 

In July, I believe you had a thread positing Draco 75; I was skeptical from recent failures, but then pleasantly surprised seeing it with the 15 x 70, but couldn't see it with 7x.   

 

I think it is about 6 deg NE of 41 and should add to the fun in this part of the sky.  My notes say it is RA 20 28 14, Dec 81 25 22, Sep 197, PA 283, 5.5/6.7.

Clastro, I'm not sure I have reported on 75 Draconis, though I have observed it in recent weeks hanging out in northern Cepheus, Draco, Ursa Minor, and Cassiopeia. Part of an attractive and bright asterism. The binocular pair is actually the AC components of the system, STH 7 -- 5.48/6.66 196.6" 282*, as you note. The AB components are BUP 211 -- 5.48/11.34 109.5" pa 11*, according to StelleDoppie. Thanks for mentioning 75 Draconis, I am going to revisit and make a definite entry in my observing log.

 

Nice work on your 41 Draconis observation. 

 

Fiske

Edited by Fiske, 06 October 2021 - 11:37 PM.

[Fiske]

Took a shot at 41 Dra with a pair of Tasco International 440 7x50.  Unable to resolve handheld no matter how hard I tried to brace, I ended up makeshift mounting on a tripod and I was able to resolve the double, just for giggles threw a pair of Sunset 7x35 JB77 and was still able to resolve.  Although, I was unable to resolve handheld but it does amaze me how good the glass is in these vintage binoculars and what you can see when mounted.  Ended running up the Milkyway from Sagittarius hitting all the known fuzzies finishing up on NGC 7000. 

Well done, Scott. Only resolvable in the largest binoculars indeed.  And congrats on your fine collection of vintage glass.

 

Now I'm going to have to give 41 Draconis a try with the mighty Kowa 6.5x32. 

 

Edited by Fiske, 06 October 2021 - 11:38 PM.

[Fiske]

I had a go at 41 Draconis last night with the Kowa 6.5x32 and the Nikon 7x35 AE binoculars, both mounted, and could see it as two stars in contact with both instruments but could not resolve it into separate stars. It was slightly easier to see in the 7x35.

 

I also visited 75 Draconis following clastro's lead, a fine binocular double in a nice starfield, both stars warm white, and easily observed handheld with both the Kowa and Nikon. 

 

I was able to resolve 61 Cygni (5.20/6.05 31.87" pa 153.5*) with both instruments, mounted, the fine orange tone easily seen even with such small apertures. While visiting 61 Cygni, don't miss the nearby open cluster NGC 7063 positioned by a pleasing triangular asterism. It's somewhat faint with 32/35mm binoculars, but can still be seen. Better with 10x50s and up. A fun and easily overlooked cluster. 

 

I was doing comparisons of various OB and APM binoculars mounted in turn on an Oberwerk PM1 p-gram, and continuing to roam in Cygnus, came across the open cluster NGC 6871, in such a rich star field it was not well separated, at least in suburban skies. What caught my attention was three fine binocular double stars, at least for slightly larger instruments, inside the boundaries of the cluster -- SHJ 314 (6.78/7.0 36.3" pa 28*), SHJ 315 (7.89/8.73 20.2" pa 236*), and SHJ 316 (7.79/8.82 69.4" pa 323*). All in close proximity. A lovely find. 

 

Seeking out the open cluster NGC 752 in Adromeda I realized that a guide star for the cluster, 56 And / STFA 4 is an excellent double for smaller binoculars (5.79/6.04 202.5" pa 298*), the primary warm white and the secondary amber. NGC 752 is an enjoyable open cluster in suburban skies, large and loose, particularly rewarding for 70 and 80mm instruments.

 

My best double star find of the evening was STF 292 near 12 Persei, about 2.5 degrees due south of the open Cluster M34 (another fine object in suburban skies, even for smaller binoculars). Both AB components of STF 292 (7.56/8.23 23.5" pa 212*)  are bluish white and lovely in the same field with the warm white 5th magnitude 12 Persei, the secondary slightly fainter, the star closer to 12 Per. I could just resolve the pair with a Fuji 10x50 binocular mounted. An outstanding binocular double star, gorgeous in 15/16x70 and 20x80mm binoculars.

 

Fiske

 

Edited by Fiske, 09 October 2021 - 08:59 AM.

[Patowl]

Thanks again for the nice doubles recommendation.
Directly on my to do list!

As this discussion is rolling about doubles, last night I had a wonderful time observing 61 Ophiuci, with 10x50. Really looking alike the previous doubles quoted as 41 Dra and 20 Gem. Wonderful.
And beeing in the neighborhood I couldn't ignore the true beaty of Theta Serpentis, definitely one of the small binoculars doubles standout.

Clear skies.

[Fiske]

Well I'm adding 61 Ophiuchi and 20 Geminorum to my own list. Thank you for mentioning them, Pat. Alya, Theta Serpentis, is one of the binocular greats for sure. It strikes me as looking like part of Aquila because of how the Serpens boundary projects into the neighboring constellation. 

 

Another binocular great currently visible is Kuma / Nu Draconis / STFA 35 (4.86/4.90 62.1" pa 311*) which is the faintest of the four stars making up the head of Draco. It features in a report I am working on about another double in Draco, STF 2398.  (Because in my search for 2398, I initially used Kuma and Rastaban as pointer stars instead of Kuma and Grumium, which was not exactly helpful for locating my quarry.   Why aren't any of these star patterns matching my chart? Eventually, after about 15 minutes of fruitless searching, I back tracked. Oh. )

 

More on that in an upcoming post.

 

Fiske

[scottmm2012]

I'm just kicking dirt here in my cloudy skies.  Waiting for a good crisp clear night to hit the other recommendations.

[Fiske]

I'm just kicking dirt here in my cloudy skies.  Waiting for a good crisp clear night to hit the other recommendations.

Clouds here too, Scott.

 

[Fiske]

At long last here is a report of my adventure with STF 2398 (some assembly was required  ).

 

STF 2398 Draco / Gliese 725
18h 42m +59*38'
9.11/9.96 10.88" pa 182.5*

 

I came across the double star in Robert Burnham's Celestial Handbook, vol 2 pp. 869-70, which is a treasure trove of astronomical knowledge (some significant percentage of which is outdated but still interesting) and lore invaluable to celestial adventurers. Burnham's own story is odd and ultimately sad. A lengthy bio can be found on Tony Ortega's website, The Underground Bunker. 

 

Burnham's entry for STF 2398, which is the 15th closest star system to our own (11.4 ly), comprised of a pair of red dwarf stars having an unusually high proper motion (listed by Burnham as 2.28" annually), includes star field depictions (presumably from photographic plates which are not specifically identified) showing the motion between 1941 and 1967. Here is a fun chart on space.com listing the closest stars to our solar system. And here is a splendid image of the double taken by Steve Smith in October 2018 on display in the Cloudy Nights Double Star forum topic devoted to the double star. Thank you, Steve! 

 

The first part of the adventure was just locating the darn thing, which is said by Argyle, Swan, and James in their Anthology of Visual Double Stars (STF 2398 is entry #140) to be one of the more difficult to locate in their catalog. I read that, scoffed, and then was repaid for my skepticism by taking a wrong turn at Kuma (a famous and outstanding binocular double star) and heading toward Rastaban instead of Grumium, thanks to which I spent 15 minutes or so lost among the stars until if finally occurred to me that something was amiss and I discovered my mistake by backtracking to Kuma and double checking my initial pointer stars. 

 

 

After heading in the correct direction, the triangle of Omicron/39/45 Draconis was easy to spot and the challenge of locating STF 2398 was considerably simplified.

 

 

While tracking down STF 2390, I happened to notice Milburn 1079 in the vicinity (9.54/11.41 34.1" pa 203*) but realized it was too wide and the secondary was far too faint for it to be STF 2398. I was observing with an Oberwerk 100XL-SD and Pentax 7mm XW eyepieces (80x) from our club observatory. I'm not sure it would be visible in 10x50 binoculars even as a single star. There might be more of a chance of observing it with 20x80 binoculars from a good site. I had intended to attempt some observations from my driveway but it is already too far west so that will have to wait for next spring. It was easily observed and resolved with the 100XL, both stars show a distinct reddish tint. 

 

Here is a Simbad image of the double, the red arrow showing the proper motion in relation to the illustrations from Burnham's handbook.

 

 

I had innocently imagined seeing the small triangular asterism near the double, but my hopes were dashed by the actual view, only one other star was visible in the field (HD 238928). The brightest star in the triangle is nearly 13th magnitude, which was too faint for the 100XL at the Louisburg location (Bortle 5ish skies). I look forward to trying again with the 100XL from the club's dark sky site near Butler Missouri, much darker than the skies in Louisburg, Kansas. I may break down and observe it with a telescope, too. I don't know how to list data for the fainter stars in the Simbad image, but it might be possible to do so. The other stars in the triangle are probably in the 13-14 magnitude range and the two fainter stars near the apex could be under 14th magnitude from their appearance in the image.

 

 

If you decide to take up the challenge of STF 2398, I hope you will follow up here to recount your adventures.

 

Thank you for reading. 

Edited by Fiske, 10 October 2021 - 05:48 PM.

[Patowl]

Oh Fiske, thank you very much for this great contribution.
Talking about Cygnus doubles above, I realized I didn't tell you about my favorite binocular double, I 'm pretty sure you already know it , but I just can't take the risk you miss it, and others may be interested
So if you happen to navigate through the left wing of the mighty Cygnus, don't miss 16 Cygni (6/6.2 sep 39,7" both G1.5V spectral class) which is a stunning colorful binary, with many interesting physical characteristics I let you find out.
Clear skies

[Fiske]

Pat,

 

I'm glad you enjoyed the STF 2398 excursion, which I'm guessing is TMI for some. 

 

And thank you(!) for mentioning 16 Cygni. It's so close to NGC 6826, the Blinking Planetary nebula, that there is no way I have not seen it, but so far I have not found any notes in my journals about 16 Cygni. Remarkable how selective we can be in our pursuit of DSOs.   I have observed 6826 many times, quickly found multiple entries in my journals, but so far nary a mention of 16 Cygni. Anyway, it sounds splendid, and I am hoping to view it tonight.

 

Please share whatever fun binocular doubles you come across in your rambles. Your reports will always be appreciated.

 

Fiske 

Edited by Fiske, 11 October 2021 - 05:57 PM.