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Adventures with Binocular Double Stars

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#1 Fiske

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Posted 21 October 2021 - 09:45 PM

I am continuing a topic begun with 41 Draconis under a more general heading because one can roam all over the sky viewing binocular double stars, among sundry other things. Any number of doubles outside of Draco have already been reported in the original topic. Ironically, I'm going to start the new topic again with 41 Draconis along with a double star in Camelopardalis, Struve 1694, which I stumbled upon when comparing 41 Dra in various binoculars. The two doubles are so similar in appearance it took a minute before I realized I was looking at a different system. lol.gif After studying it for a short time, I realized the nearby field stars somehow looked different. No wonder, considering I wasn't even in the same constellation. Both are fun challenges for mounted 10x50 binoculars -- way too close to resolve hand held. That might be done with an IS binocular, however. They are gorgeous in larger binoculars.

 

STF 2308 / 41 Draconis
18h00m +80*00' 
5.70/6.0 18.77" pa 231.8*

The components are close but nevertheless fully resolved with 10x50 binoculars. The colors of the two components are often reported as creamy white but they look more bluish to me, at least with small to moderate size instruments. A slight different in magnitude can be seen and in larger instruments the primary does look slightly warmer in tone.

 

STF 1694 Camelopardalis

12h49m +83*25'

5.29/5.79 21.8" pa 324*

Slightly brighter and wider than 41 Dra, the components are a little easier to resolve but still quite close in 10x50 instruments -- observed with a Nikon 10x50 AE binocular. With the 100XL-SD+14mmXW eyepieces, the primary is light yellow and the secondary a bluish white. Color not discernable in the 10x50.

 

 

med_gallery_2707_15673_37805.jpg


Edited by Fiske, 21 October 2021 - 09:47 PM.

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#2 The Ardent

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Posted 21 October 2021 - 10:12 PM

What I find mysterious about Ursa Minor is that each star of the bowl has a wide companion or two. Each corner is a little wider pair(s) than the last. 


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#3 Fiske

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Posted 21 October 2021 - 10:50 PM

What I find mysterious about Ursa Minor is that each star of the bowl has a wide companion or two. Each corner is a little wider pair(s) than the last. 

The observing possibilities are ENDLESS!

 

Bowling for doubles. I like it! grin.gif

 

Thank you, Ray.


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#4 Fiske

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Posted 21 October 2021 - 11:15 PM

Plus, as an added incentive to keep up with the Bino Double adventure, observations will occasionally include comparative binocular observations. Like this one, for example. wink.gif

 

STF 3053 Cassiopeia

00h02m +66*06'

5.96/7.17 15.2" 70*

Observed from my suburban driveway, Wednesday 20 October. (Full moon.)

 

I decided to look up this colorful double after reading about it in the 5th edition of Turn Left at Orion, a terrific observing guide that has been significantly reworked and expanded in this latest edition, with many eyepiece sketches by the authors and etc.

 

With the 100XL-SD+10mmXW eyepieces, the primary is a bright lemon yellow and the secondary a light neon blue. Strikingly beautiful. I was not able to resolve it with the Nikon 10x70 SP (not a big surprise considering the separation). I was able to resolve it with the APM 16x70 ED MS, but the components were too close to distinguish color. With the 20x80 ED MS the components are well resolved and the colors are discernable, though not so vibrant as in the 100XL. Here is the interesting bit, though, the Oberwerk 20x65ED provides a slightly better view than the APM 20x80 -- the primary is slightly sharper and the colors are slightly more distinct. Partially, this could be due to the additional aperture of the x80 increasing the brightness of the primary, but the excellent correction and sharpness of the 65ED are probably factors. The 20x65ED is a fun binocular for double stars without a doubt.

 

Thank you for reading. flowerred.gif


Edited by Fiske, 21 October 2021 - 11:15 PM.

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#5 aznuge

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Posted 22 October 2021 - 12:09 AM

I was trying out some new eyepieces tonight for my 100mm BTs - checking out the moon, then stopping by at a couple of familiar doubles: Lyra double double (easily split both at 110x) and Alberio (beautiful as always).  Then I saw this thread and the STF 1694 suggestion with 10x50s.  So I mounted some up and took a look.  That's when I saw this lovely, tight, yellow orange semicolon pointing almost north.  I had never logged this before.  Its perfect for mounted 10x50s.

 

nuge


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#6 Fiske

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Posted 22 October 2021 - 07:59 AM

I was trying out some new eyepieces tonight for my 100mm BTs - checking out the moon, then stopping by at a couple of familiar doubles: Lyra double double (easily split both at 110x) and Alberio (beautiful as always).  Then I saw this thread and the STF 1694 suggestion with 10x50s.  So I mounted some up and took a look.  That's when I saw this lovely, tight, yellow orange semicolon pointing almost north.  I had never logged this before.  Its perfect for mounted 10x50s.

 

nuge

Wow! That is an impressive optics performance, Nuge. (As JG is want to say.) Well done. waytogo.gif

 

Thank you for sharing your observation.

 

I suspect my eyes just aren't sharp enough to see that level of detail at 10x. I'll try with the APM 12x50 and take a run at it with a few 10x50 instruments, including the OB 10x50 Ultra, which seems to have something a bit extra in the sharpness department at the center of the FOV.

 

When observing the moon with a 100mm BT, are you doing anything to reduce the brightness? Viewing the moon near full with a 100mm BT, I worry that it is so bright it might not be good for my vision. I can't use neutral density filters with my beloved Pentax WX eyepieces in the 100XL -- they won't come to focus with the added extension. One solution would be a filter that threads into the bottom of the eyepiece, which is possible but I haven't found any designs like that, and removing them would be a pain, probably requiring a special tool. I guess the obvious alternative would be to mask the aperture.

 

What eyepieces were you trying out?

 

Fiske


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#7 aznuge

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Posted 22 October 2021 - 01:14 PM

Wow! That is an impressive optics performance, Nuge. (As JG is want to say.) Well done. waytogo.gif

 

Thank you for sharing your observation.

 

I suspect my eyes just aren't sharp enough to see that level of detail at 10x. I'll try with the APM 12x50 and take a run at it with a few 10x50 instruments, including the OB 10x50 Ultra, which seems to have something a bit extra in the sharpness department at the center of the FOV.

 

When observing the moon with a 100mm BT, are you doing anything to reduce the brightness? Viewing the moon near full with a 100mm BT, I worry that it is so bright it might not be good for my vision. I can't use neutral density filters with my beloved Pentax WX eyepieces in the 100XL -- they won't come to focus with the added extension. One solution would be a filter that threads into the bottom of the eyepiece, which is possible but I haven't found any designs like that, and removing them would be a pain, probably requiring a special tool. I guess the obvious alternative would be to mask the aperture.

 

What eyepieces were you trying out?

 

Fiske

Agreed - 32 CAM deserves repeated views with multiple 10x50s smile.gif as well as other powers.  Should be interesting to compare and contrast separations and colors with the different instruments.  Also I like the "how low can you go" concept for doubles - refreshing after trying to push the limits for doubles with 100mm BTs.  Last night I made additional stops at Alberio and Gamma DEL with 10x50s - beautiful and challenging in that order.

 

Regarding the moon - coincidental to your question I  received my first pair of  eyepiece filters recently and tried them out briefly last night.  These are the Neodymium Moon and Skyglow filters from Baader which screw into the bottoms of the eyepieces.  I had them on 12.5mm Morphs and did see the dampening of the brightness of the moon.  But the jury is still out since I was more preoccupied with trying to track a star occultation by the moon and spent most of the lunar observing session behind the unfiltered 5mm Delites.  But the view was definitely darkened with these Baader filters at 44x and I had no problem with focus after installing them.  I also tried one 5mm eyepiece with the filter during a sunspot session yesterday and could see the difference when viewing the sun and no loss loss of clarity through the one filtered eyepiece.  Both objectives had solar filters on them of course.


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#8 hallelujah

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Posted 22 October 2021 - 02:26 PM

 

 

the excellent correction and sharpness of the 65ED are probably factors.

The 20x65ED is a fun binocular for double stars without a doubt.

 

Thank you for reading. flowerred.gif

waytogo.gif
 



#9 Fiske

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Posted 23 October 2021 - 05:44 PM

Here is a challenging triple for binocular telescopes -- nuge might be able to pick it out with a 10x50. grin.gif  (I was delighted to resolve it with the 100XL-SD.) Another item listed in the excellent guide, Turn Left at Orion (5th edition).

 

STF 262 / Iota Cassiopeiae
02h29m +67*24'
AB 4.63/6.92 3.03" pa 228*
AC 4.63/9.05 6.7" pa 117*

Saturday 16 October 2021
Observed with 100XL-SD+5mmXW (112x). All three components resolved, diffraction ring visible in primary and seeing not particularly great. Primary white, secondary shows a faint hint of yellow.

 

Another challenge (also from Turn Left)

 

STF 3049 / Sigma Cassiopeiae

23h59m +55*45'

4.99/7.24 3.1" 326*

Wednesday 20 October 2021

100XL-SD+5mmXW

Warm white primary with a minute and close ruddy orange companion. According to notes in SkySafari both stars are blue-white main-sequence but color contrast effects result in them often being described as white and yellow. To my eyes the secondary was an even deeper color. Odd to think they are of the same spectral class. Quite distant, as well: 1400 ly. Anyway, another fun double for binocular telescopes.

 

 

 

 

 


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#10 Fiske

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Posted 23 October 2021 - 06:08 PM

Sigma Cassiopeiae is included in the Astronomical League Double Star program. I observed and sketched it on 10 November 2001 using a Celestron G9.25 and 18mm Radian eyepiece. Saw the colors as white and gray-white. The thing is, I frequently observe the cluster NGC 7789, which has been nicknamed Caroline's Rose (in honor of Caroline Herschel). Sigma Cassiopeiae and a bright companion star along with Rho Cassiopeiae and another bright companion make convenient guides to the cluster's location -- it appears midway between them. Almost any observing session when Cassiopeia is in a reasonable observing position, I view it and have done so for many years. Yet, in all that time, I'm not sure I even once recalled that Sigma is an excellent, close double star. So intent do we become on specific objects in the sky -- it is easy to lose sight of the context in which we view them.


Edited by Fiske, 23 October 2021 - 09:37 PM.


#11 The Ardent

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Posted 23 October 2021 - 10:09 PM

STF 1694 is labeled as 32 Cam on some atlases. The 32 is not the commonly used  Flamsteed number. This can lead to confusion. See below: 

https://en.m.wikiped...org/wiki/Σ_1694

 

No listing for 32 Cam in Stelladoppie

 

https://www.stelledo...?iddoppia=55026

 

I believe that when I first observed this double it was labeled 32 Cam in my Edmund Mag 6 star atlas. 

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#12 Fiske

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Posted 23 October 2021 - 10:48 PM

Thank you for sharing these details, Ray. And the wonderful image. smile.gif

 

I was not familiar with the 32 Cam catalog entry, but Sissy Haas does refer to it as 32 Cam in Double Stars for Small Telescopes (p. 33). Sue French includes it in her "Between the Bears Star Hop", Deep-Sky Wonders (p. 102), explaining that the reason 32 Cam is out of order in the eastward progression of Flamsteed numbers is because the number comes from Prodromus Astronomiae, the 1690 catalog of Johannes Hevelius. She says that most of Hevelius's numbers have fallen by the wayside but 32 Cam can still be found on many star charts to "the puzzlement of stargazers." I'm combing through various atlases to see if it is listed as 32 in any of them. I must confess to being completely oblivious of the issue, not puzzled by it. wink.gif

 

Also of note is that 1600 years ago, 32 Cam was the closest star to the celestial north pole. Ian Ridpath includes some details about this on his Star Tales website.


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#13 Fiske

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Posted 23 October 2021 - 11:10 PM

Okay, it is labeled 32 (and also STF 1694) in the first edition of the Cambridge Double Star Atlas. 



#14 aznuge

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Posted 24 October 2021 - 01:03 AM

I double checked tonight with two more pair of 10x50s.  Also tried 12x42s,10x42s, and 7x50s on STF 1694 / 32 Cam.  I could split the double with all but the 7x50s.  I saw a little color differential between this pair - some of the instruments showed the fainter 2nd toward the NW more white/gray compared to the yellow/orange primary.  Thin clouds came in before I could try any 8x binoculars.  Then I got distracted with Gamma Del in the western sky for the rest of the session. Also I did not try the IS 10x42s yet on 32 Cam, so more observing of this very interesting double is sure to come.


Edited by aznuge, 24 October 2021 - 02:03 AM.

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#15 Fiske

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Posted 24 October 2021 - 11:23 AM

Nuge,

 

Thanks so much for sharing these observations of STF 1694 with various instruments. I'll put the Nikon and APM 7x50s on it. I saw it as two stars in contact with the Nikon 7x35 AE. We'll see if either instrument does a better job resolving it. Trying 8x is a good idea, too. smile.gif I haven't added or made a mount adapter for the Steiner 8x56, but the Nikon 8x42 HG works with standard tripod adapters so I will give that a try.

 

Somehow I had it in my head you were doing observations of STF 3053 in Cassiopeia, which is a difficult 10x challenge given 15 seconds separation and more than a magnitude difference between the components. I could not resolve it with the Nikon 10x70 SP. It would be interesting to see what could be done with a 10x instrument on a more evenly matched 15 second double -- 100 Herculis (mentioned by Patowl in the 41 Draconis double star topic) would be a good test case but is too far in the west now from my home location. I'll do a search in stelladoppie to pick out a few fall and winter constellation candidates in the 6 mag / 15 second range.

 

What observations were you making of Gamma Del? Another double I love. wink.gif

 

Fiske


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#16 duck2k

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Posted 24 October 2021 - 01:41 PM

Double Stars are fun! Carbon Stars, Variable Stars. Great objects to observe! :)
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#17 Fiske

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Posted 24 October 2021 - 06:12 PM

Here is a list of double stars that should push the limit for 10x instruments. The initial search criteria of 5-6 mag in 14-16" separation range had to be expanded somewhat to come up with a reasonable number of candidates. It seems like 100 Herculis is quite a rare combination in this regard. smile.gif

 

med_gallery_2707_15684_365094.jpg

 

Some nice candidates in the query result, though. Here is a link to the stelledoppie search. Happy hunting to those inclined to test their 10x observing prowess. Mounts pretty much NOT optional. Well, unless using an IS binocular. grin.gif  

 

watching.gif


Edited by Fiske, 24 October 2021 - 06:48 PM.

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#18 aznuge

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Posted 24 October 2021 - 09:37 PM

Double Stars are fun! Carbon Stars, Variable Stars. Great objects to observe! smile.gif

I hope to get to the ALOP for binocular variable stars soon, but Fiske keep throwing down the double star gauntlet.lol.gif lol.gif   It's all good, though!


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#19 aznuge

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Posted 24 October 2021 - 09:55 PM

Nuge,

 

What observations were you making of Gamma Del? Another double I love. wink.gif

 

Fiske

First, nice doubles list for the 10x50s in #17.

 

For Gamma Del (9.6" separation I believe) I was working my way up from 10x to determine how low I could go to split this nice double.  Got to 15x56 and it started to show elongation.  Then jumped to BTs (50x82) and viewed the target clearly of course.  Now to fill in some mags in between to find lowest to split - its a work in progress...


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#20 Fiske

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Posted 24 October 2021 - 10:25 PM

First, nice doubles list for the 10x50s in #17.

 

For Gamma Del (9.6" separation I believe) I was working my way up from 10x to determine how low I could go to split this nice double.  Got to 15x56 and it started to show elongation.  Then jumped to BTs (50x82) and viewed the target clearly of course.  Now to fill in some mags in between to find lowest to split - its a work in progress...

Thank you, Nuge. smile.gif Stelledoppie is a wonderful thing, and I'm only scratching the surface of what can be done with it.

 

I observed Gamma Del with the 100XL-SD and 20XW in August, that is 28x, and noted that it was fully resolved at that magnification but the 10mm XW (56x) was a nicer and more enjoyable view. My lineup to test it would be the APM 16x70, OB 20x65ED (which may be capable of resolving it), 80XL w/20XWs, which would be 22.5x. Oh! OB 25x100, would be the next step up. grin.gif I'll add this to my observing project list.

 

There is a nice double in the same field with Gamma, BTW. I've been meaning to reobserve it and spend some more time on the colors.

 

STF 2725 Delphinus
20h46m +15*54' / Sky Atlas 2000: 16; Uranometria 2000: 84
7.54/8.20 6.2" pa 11.9*

Sunday 15 August 2021

Easily resolved with the 100XL-SD and 10mm XW eyepieces and an enjoyable field along with Gamma. The colors are vaguely yellow and white, but a bit hard to discern.

 

Also, I recalled an observation from back in February with the 20x65ED, of 41 Aurigae, which showed that instrument's mettle. I'm even more interested now to try it on Gamma Del, and I'm not sure it isn't capable of resolving STF 2725 as well. We will see. wink.gif

 

STF 845 / 41 Aurigae

06h11m +48*43'

6.16/6.86 7.5" pa 358*

Friday 5 February 2021

I was able to resolve this with the 20x65ED, exceeding my expectations considerably. Two bright stars nearly in contact. Really I was delighted with this observation.


Edited by Fiske, 24 October 2021 - 10:36 PM.

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#21 clastro8*

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Posted 25 October 2021 - 07:40 PM

From above, 'Sigma Cassiopeiae is included in the Astronomical League Double Star program,' ie in the telescope double star program (not binocular) where, at sep = 3 " IMHO it fitfully belongs.

 

I eyeballed the AL advanced bino double star program and didn't see any sep's in the single digits.wink.gif



#22 Fiske

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Posted 25 October 2021 - 09:29 PM

Clastro,

 

Whatever double star can be resolved in a binocular or binocular telescope is fair game as far as I'm concerned. wink.gif

 

My largest aperture BT is 100mm, which I'm guessing won't go much below 2" for an evenly matched double. If someone chimes in with observations made with a larger BT, I will applaud their efforts and cheer them on. 

 

Fiske


Edited by Fiske, 25 October 2021 - 09:54 PM.


#23 clastro8*

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Posted 26 October 2021 - 12:03 PM

Yes, I guess so.  But I was hoping for bino doubles targets available to the vast majority of bino users especially wannabees likes myself or other even newbees to the hobby..

 

I'm still working on the Draco 41 link you started earlier, too many cloudy nights get in the way but I will get there.


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#24 Fiske

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Posted 26 October 2021 - 12:38 PM

But I was hoping for bino doubles targets available to the vast majority of bino users especially wannabees likes myself or other even newbees to the hobby..

Of which it is my intention to include many in this topic. wink.gif

 

In fact, the majority of the double stars I report will be accessible to a wide range of instruments, with an occasional binocular telescope challenge double in the mix. 

 

Looking forward to your report on 41 Draconis, Clastro. STF 1694 in Camelopardalis  is not far from 41 Dra and in the same brightness and separation range, so another good double for a wide range of binoculars. Details in the first post in this topic.

 

Fiske


Edited by Fiske, 26 October 2021 - 12:39 PM.


#25 aznuge

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Posted 26 October 2021 - 04:38 PM

 

I observed Gamma Del with the 100XL-SD and 20XW in August, that is 28x, and noted that it was fully resolved at that magnification but the 10mm XW (56x) was a nicer and more enjoyable view. My lineup to test it would be the APM 16x70, OB 20x65ED (which may be capable of resolving it), 80XL w/20XWs, which would be 22.5x. Oh! OB 25x100, would be the next step up. grin.gif I'll add this to my observing project list.

 

Yes, the OB 20x65EDs may be capable - but could be right on the edge.  I checked last night with 21x82 BTs and just could split Gamma Del  - more like the "snowman with a belt around the middle" kind of a split, so could use more mag for a comfortable view.  I then swung the BTs back to 32 Cam for a relaxing, beautiful, and comfortable view of STF 1694.  This (21x) was my favorite view of that fine double yet...


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