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61 Cygni

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#1 Dave Mitsky

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Posted 31 July 2021 - 02:22 AM

I was doing some casual observing at the Naylor Observatory on Friday night using Celestron IS 15x50s and a 17" f/15 classical Cassegrain.  A fellow ASH member was using his 8" f/4.9 Orion Newtonian.  He was looking at Omicron Cygni at the time.  A bit later I asked him if he had seen 61 Cygni.  He put Piazzi's Flying Star into view at 111x and not long afterwards mentioned that it was a binocular double star according to the program he was using.

 

I had never tried resolving 61 Cygni before with a binocular and after a few minutes of careful observing with the 15x50s I definitely had a split.

 

https://frostydrew.o...show/entry-761/

 

https://skyandtelesc...-cygni06032105/

 

61 Cygni is on the Astronomical League's Binocular Double Star list.

https://www.astrolea...e Star List.pdf


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#2 gwd

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Posted 31 July 2021 - 03:14 AM

It caught my eye while slewing from M39 to M29 and RS Cyg a few nights ago.  I had to look it up.   If the haze cleans out tonight I’m intend to search for AX Cyg.

 

Cygnus is full of interesting binocular fields.  When I lived under dark skys I began noticing dark nebula in Cygnus.   It surprised me when I recognized the North America nebula when I wasn’t looking for it.  


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#3 Jon Isaacs

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Posted 31 July 2021 - 05:28 AM

Dave:

 

61 Cygni looks very doable in binoculars, according to StellaDoppie:

 

The separation is 31.90" with magnitudes 5.20 and 6.05.

 

I'll be giving it a try,

 

Thanks

 

Jon


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#4 Fiske

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Posted 31 July 2021 - 07:25 AM

Thank you for starting this topic, Dave. smile.gif

 

61 Cygni is the first star to which an accurate distance was determined (by Friedrich Bessel in 1838) so it is of historical interest in addition to being an attractive double star. Enjoyable even in smaller telescopes. I made observations of it with 10x50 and 7x50 binoculars in early July, reported in this (slightly off topic) Binocular forum postwink.gif  The instruments must be mounted, and it is difficult in a 7x50 -- I found it necessary to wear my glasses because even mild astigmatism interferes with resolving it at such low magnification. (Well, non-IS instruments must be mounted. Canon 10x42L IS anyone?)

 

Although it is not difficult to resolve in mounted 10x50 binoculars, I personally find it more enjoyable at higher magnifications. It's a fine view with 15/16x instruments, and I observed it last night with an Oberwerk 100XL-SD at 28x while navigating to a nearby star field.

 

Bessel determined a distance of 10.4 LY, quite close to the currently understood distance of 11.4 light years. Observations of the star where made six months apart and the known diameter of the Earth's orbit was used to triangulate the distance based on precise parallax measurements. The size of the Earth's orbit had been accurately determined from observations of the transit of Venus in 1769, made by expeditions to different parts of the earth. Edmond Halley had suggested the idea in 1716.

 

61 Cygni was chosen for observation by Bessel due to its high proper motion (apparent change compared with stars in the same field of view) because it is one of the closer stars to our own solar system (thus Piazzi's Flying star).

 

Fiske


Edited by Fiske, 31 July 2021 - 07:34 AM.

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#5 Dave Mitsky

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Posted 31 July 2021 - 11:24 AM

There's a section on 61 Cygni in the article Touring Cygnus with Binoculars in the September issue of Sky & Telescope.  Author Matthew Wedel mentions that 61 Cygni moves one Jupiter diameter in approximately 8 years.  

Two images showing 61 Cygni's change in position over a period of 32 years appear at https://windows2univ...iseasepart2.pdf

 

61 Cygni's separation is about 3.8 arc seconds less than that of Albireo.


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#6 Dave Mitsky

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Posted 31 July 2021 - 11:29 AM

Another list of binocular double stars can be found at http://www.carbonar....inodoubles.html


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#7 adlibitum

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Posted 31 July 2021 - 11:37 AM

I’ve observed 61 Cygni several times with Canon 10x42 IS which provides a good split. I find them rather golden in color. And whenever I hear “Piazzi’s flying star” i can’t help thinking of a trapeze act.


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#8 Jon Isaacs

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Posted 02 August 2021 - 08:08 AM

I’ve observed 61 Cygni several times with Canon 10x42 IS which provides a good split. I find them rather golden in color. And whenever I hear “Piazzi’s flying star” i can’t help thinking of a trapeze act.

 

Last night I had my 10 inch Dob out and I remembered this thread on 61 Cygni.  I wasn't setup to mount binoculars and the most bino magnification I have in San Diego is 10x so I just took a look the Astro-Tech 50mm RACI finder I was using.  I did get a clean split at 10x but I don't think I could hand hold 10x binoculars steady enough to make that split.  At 14x it was a wider split.  I went all the way up to 78x with nice round stars. 

 

I may be able to dig out a binocular mounting bracket, if it's clear tonight, I will give it a try.  

 

If anyone has an idea of making a pair of 50mm RACI finders into a pair of 50mm RACI binoculars, these could be a good candidate.  The tube is 61.5 mm in diameter which could be an issue but optically they are very good with a nice helical focuser. You would have to remove the dewshield, it simply unthreads.  I was able to split Porrima earlier this year. 

 

 And they are only $45.  

 

https://www.cloudyni...45-50mm-f5-rft/

 

Jon


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#9 Dave Mitsky

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Posted 02 August 2021 - 11:47 AM

Here's part of what Phil Harrington had to say about 61 Cygni in Touring the Universe through Binoculars.

61 Cygni is a challenging double star through binoculars. This binary system consists of two brilliant magnitude 5.2 and 6.0 orange type-K suns separated by about 29" of arc. While 61 Cygni is difficult to resolve using only 7x, larger glasses should be capable of just distinguishing the two stars.

 

http://www.philharrington.net/sw8.htm


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#10 Fiske

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Posted 02 August 2021 - 12:05 PM

I have Phil's book. It's a good one. I find the components can be resolved with a mounted Nikon 7x50 SP, but it is difficult as Phil says. More about pushing the envelope of the instrument's resolution capability than enjoying an aesthetically pleasing view of Albireo.

 

Fiske



#11 Dave Mitsky

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Posted 02 August 2021 - 01:39 PM

I have Phil's book. It's a good one. I find the components can be resolved with a mounted Nikon 7x50 SP, but it is difficult as Phil says. More about pushing the envelope of the instrument's resolution capability than enjoying an aesthetically pleasing view of Albireo.

 

Fiske

Touring the Universe through Binoculars was published in 1990.  The separation of 61 Cygni is now a bit larger, although I've come across some conflicting figures.

Albireo?



#12 Dave Mitsky

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Posted 02 August 2021 - 01:46 PM

Phil posted a Cosmic Challenge article on 61 Cygni on Cloudy Nights four years ago.  There's a graphic showing the increasing separation of 61 Cygni A and B.

 

https://www.cloudyni...ying-star-r3111


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#13 Fiske

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Posted 02 August 2021 - 01:58 PM

Touring the Universe through Binoculars was published in 1990.  The separation of 61 Cygni is now a bit larger, although I've come across some conflicting figures.

Albireo?

Oops! 

 

tonofbricks.gif

 

From a session when I was observing both Albireo and 61 Cygni with 7x and 10x50 binoculars. 

 

Fiske


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#14 gwd

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Posted 02 August 2021 - 09:46 PM

I compared Albereo with 61 Cygni last night using 20x60 image stabilized.  The 61 Cygni separation appeared wider but I attributed that to glare and the larger difference in magnitudes for the Albireo pair.   Maybe it really is wider now.  
 

Under my light polluted sky, I look for 61 Cygni around the intersection of the great circle from Vega to Sadr (extended beyond Sadr) and the great circle from  Tarazed to Aljanah (extended beyond Aljanah).   


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#15 aznuge

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Posted 02 August 2021 - 11:40 PM

Phil's book had a big influence on my interest in binocular astronomy.  I purchased a couple pair of Carton Adlerblicks decades ago (7x50 and 10x50) after reading his book.  I still have the 10x50s today, but gave the 7x50s to my Dad quite awhile back.  My mostly casual binocular astronomy since then has greatly intensified in the last couple years.  Thanks Dave for re-posting this challenge! 

 

About 15 minutes ago I viewed 61 Cygni AB for the first time.  It is for sure a very impressive double.  I observed these twins at 44x using APM 100mm BTs.  No kidding they are orange smile.gif   like  beady, sparkling eyes from Hades flame.gif . The primary seems a little bit more toward red and the 2nd more toward yellow.  Perhaps its just the magnitude difference.  A separation of ~30" seems about right, and I would put the PA at about 150 degrees or so.  The intense orange colors make this double unforgettable!

 

nuge


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#16 Napp

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Posted 03 August 2021 - 12:14 AM

Thanks everyone for the info and links.  I am working the AL Binocular Double Star Observing Program.  I will definitely observe 61 Cygni - that is if it will stop clouding and raining here in northeast Florida.  Assuming the forecast is accurate that won't be until next week at the earliest.  


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