Favourite doubles

[MylesGibson]

What are everyones favourite double/binary stars to observe and why?

Be nice to get a big list going so anyone interested in looking can always find something new!

I personally love double stars with nice colour differences. I have a list in the following location: 

 

Feel free to check them out and list your favourites here!

[NGC 1502]

Excellent topic👍

Looking at the list you mentioned you’ve included one of my favourite coloured doubles, Iota Cancri.  During a recent late night session I observed it rising in the east with my ED80.

This wide coloured double was an easy split at 22x in my ED80, but the colours were more apparent at 50x.
 

 

[Pixies]

Iota Cancri is nice.

Although a triple not a double, Iota Cassiopeia is one of my favourites. Pretty tight but not hard work to observe - and lovely colour differences.

Almach (Gamma Andromedae) I recently discovered. It's like Albireo, but a little tighter.

Izar (Epsilon Bootis)  Yellow primary and green/white secondary. In a Newtonian view, looks like a tiny hot-air balloon gliding by!

Theta Aurigae. A very tight double with the primary star much brighter, making it hard to split. However, it's nowhere near as difficult as Sirius. When you can split it (seeing allowing) the tiny bright pinprick of the secondary is satisfyingly distinct. Mid-winter onwards, when it is well placed for me, I use it as a test of seeing conditions as the start of a session.

Epsilon Lyra (double-double) - enough said.

[Spile]

I created a list of 500 favourite doubles from two sources a while back. These can be downloaded and imported into an app like SkEye. https://astro.catshill.com/top-500-binary-stars/

Edited November 14, 2021 by Spile

[John]

Good to see this section in the observing part of the forum now - makes a lot of sense I think

I really enjoy observing binary stars, especially with my refractors which seem to give such crisp and well defined views of the component stars. I tend mostly towards targets which will stretch me, the seeing conditions and the instrumentation so they tend to be closely separated and / or have unequal brightness components.

I can't recall all my favourites just now but I have a bunch of them as each observing season unfolds. Some stand out ones are Iota Cassiopeia, Pi Aquillae, Mu Bootis, Epsilon Bootis (Izar) Gamma Leonis (the 1st double star I ever split with a telescope !), Gamma Virginis, Zeta Herculis, Rigel, Sigma Orionis, Theta Orionis (including E & F if things are good), 52 and 32 Orionis, Lambda Orionis, Zeta Orionis (Alnitak), Alpha Canis Majoris (Sirius),  Beta Monocerotis, Castor, Delta Cygni, Mu Cygni, and Theta Aurigae  to name but a few 

(I'm sure a whole load more will pop into my brain just after I've posted this ! )

I find the Stella Doppie database a very useful source of information on binary star targets:

https://www.stelledoppie.it/index2.php?section=1

Edited November 14, 2021 by John

[Voyager 3]

9 hours ago, John said:

to name but a few 

You've left nothing more to be said .  😂

My first double would be Rigel!

[chiltonstar]

14 hours ago, John said:

Good to see this section in the observing part of the forum now - makes a lot of sense I think

 

Can get swamped by the variable star community though............☹️

Chris

[Mr Spock]

15 hours ago, John said:

I find the Stella Doppie database a very useful source of information on binary star targets:

I use Stella Doppie too. I have the data pulled out into excel for easy searching.

1 hour ago, chiltonstar said:

Can get swamped by the variable star community though

We are all in this together 

[MylesGibson]

On 13/11/2021 at 06:53, NGC 1502 said:

Looking at the list you mentioned you’ve included one of my favourite coloured doubles, Iota Cancri.  

Yes, I love this one too. It's a great winter object for me and I always give it a look with my scope! Nice easy split and great colour contrast.

@Pixies you have some nice ones on that list! I also like Zeta Cancri, or Tegmine which is easy enough to split into 2, but can be a challenge to get 3

On 13/11/2021 at 22:29, Spile said:

I created a list of 500 favourite doubles from two sources a while back. These can be downloaded and imported into an app like SkEye. https://astro.catshill.com/top-500-binary-stars/

That's awesome, I'll check that out!

15 hours ago, John said:

Good to see this section in the observing part of the forum now - makes a lot of sense I think

I think so too!

15 hours ago, John said:

I find the Stella Doppie database a very useful source of information on binary star targets:

I've not used this before! I usually use my Sky Safari app and the cambridge atlas of double stars. I'll have to have a look at this

6 hours ago, Voyager 3 said:

My first double would be Rigel!

First but not last!

1 hour ago, chiltonstar said:

Can get swamped by the variable star community though............☹️

Don't see any issue with this. They are also nice to observe over time. If you're worried about it though, make some topics on something of your choice!

11 minutes ago, Mr Spock said:

We are all in this together 

Hear, hear!

[chiltonstar]

7 hours ago, Mr Spock said:

 

We are all in this together 

I was trying to raise the issue (in my usual unsubtle way) of why doubles and variables don't have their own sections  as they do on some other fora. Rev. Dawes would be turning in his grave (once every 20.5 years).

Chris

[Mr Spock]

1 minute ago, chiltonstar said:

I was trying to raise the issue (in my usual unsubtle way) of why doubles and variables don't have their own sections  as they do on some other fora. Rev. Dawes would be turning in his grave (once every 20.5 years).

Lack of posting - there just isn't enough activity to warrant separate forums. So, everyone, get posting 

[Franklin]

In yesteryear, double and variable star observing formed the backbone of every amateur astronomers to do list.

DSO observing seems to have taken precedence now, probably due to the affordability of greater aperture telescopes in our more modern times.

Looking through my old copy of Nortons, at the lists of interesting objects accompanying each star map, I see a lot more double and variable star entries than DSOs. Times and trends may have changed but I still enjoy attempting to measure the PA and SEP of doubles with my trusty old Microguide eyepiece.

[Ian McCallum]

I found Almach by accident a few weeks ago, love the contrast in colours.

[John]

I don't record much but I did do a couple of sketches of Zeta Herculis which are separated by nearly 4 years and show the position angle change. Zeta Herc is quite a challenge with a separation of 1.5 arc seconds and a fairly large difference in the brightness of the components.

 

 

[Stu]

Same sketch, neatly rotated there.

Zeta Herc was my nemesis for a long time, and I convinced myself I couldn’t see it in any scope. Then I spotted it in my Tak Mewlon 210, followed by the 8” f8, Heritage 150p and finally my Vixen FL102S. So, a lot of this comes down to experience and knowing what to look for, and what you are looking at. Plus the seeing conditions of course.

@Ian McCallum Almach is a lovely one isn’t it, much like Albireo I guess. The contrasting colour ones are some of my favourites too. SkySafari has a nice list of coloured doubles you can import which is handy.

[Captain Scarlet]

A double I really enjoyed was one that took me by surprise: Meissa, the brightest star in the cluster that makes Orion’s head. I’d had no idea it was a pretty double and when I saw that it was, inexplicably it gave me joy!

M

[Ags]

Cor Caroli is a particular favorite of mine. I struggle to see colors in doubles but Delta Cephei always stands out. The Double Double's Double is fun in a larger scope. Alpha Centauri was my first double and will always be the "most special".

In my signature, there is a link to download my PDF of northern doubles, it has 300 doubles with a finder chart for each.

[Zermelo]

1 hour ago, John said:

I don't record much but I did do a couple of sketches of Zeta Herculis which are separated by nearly 4 years and show the position angle change. Zeta Herc is quite a challenge with a separation of 1.5 arc seconds and a fairly large difference in the brightness of the components.

 

 

I just went to my phone to check if I'd split this one myself, and realized that the Sky Safari database seems to be confused on the matter.

There are two entries for the star, one as a double and one as a variable double - but that's nothing new, I've seen it before. Both entries have the same identifying info for all the catalogues, both list the separation at 1.5" and PA 96.4°. But the one entry has the magnitudes as +2.85 and +10.78, and the other has them as +5.40 and +8.22. The RA and Dec differ by a tenth of a degree.

On previous occasions I've known Sky Safari and other sources (e.g. Stellarium) to list different combinations from the same multiple star system, apparently seeming to contradict each other. But a check on Stelle Doppie has always revealed the truth. This time, though, the SD entry has just two components, separated by 1.6" and with magnitudes +2.95 and +5.40. So the Sky Safari entries between them seem to have these two components, but what are the +8.22 and +10.78 stars?

My own Sky Safari observation claims a "probable split" in my 6" at 150x, but now I'm unsure which components I think I've identified. @John, which ones do you think you split?

(and just to add to the confusion, Sky Safari describes zeta Herculis as a "Double star in Octans"!)

[Stu]

32 minutes ago, Zermelo said:

I just went to my phone to check if I'd split this one myself, and realized that the Sky Safari database seems to be confused on the matter.

There are two entries for the star, one as a double and one as a variable double - but that's nothing new, I've seen it before. Both entries have the same identifying info for all the catalogues, both list the separation at 1.5" and PA 96.4°. But the one entry has the magnitudes as +2.85 and +10.78, and the other has them as +5.40 and +8.22. The RA and Dec differ by a tenth of a degree.

On previous occasions I've known Sky Safari and other sources (e.g. Stellarium) to list different combinations from the same multiple star system, apparently seeming to contradict each other. But a check on Stelle Doppie has always revealed the truth. This time, though, the SD entry has just two components, separated by 1.6" and with magnitudes +2.95 and +5.40. So the Sky Safari entries between them seem to have these two components, but what are the +8.22 and +10.78 stars?

My own Sky Safari observation claims a "probable split" in my 6" at 150x, but now I'm unsure which components I think I've identified. @John, which ones do you think you split?

(and just to add to the confusion, Sky Safari describes zeta Herculis as a "Double star in Octans"!)

This is what SkySafari 7 has to say which seems to have been corrected? These are for the two dates of the OPs observations. It seems Zeta Herc is now in Hercules too 😉

[Ian McCallum]

1 hour ago, Ags said:

Cor Caroli is a particular favorite of mine. I struggle to see colors in doubles but Delta Cephei always stands out. The Double Double's Double is fun in a larger scope. Alpha Centauri was my first double and will always be the "most special".

In my signature, there is a link to download my PDF of northern doubles, it has 300 doubles with a finder chart for each.

The first ever time I hear of Cor Caroli was in an episode of ST:TNG, citing a fictional exoplanet there (Cor Caroli V).😁

Edited November 15, 2021 by Ian McCallum

[Stu]

@Zermelo which version of SkySafari were you using? Just checked 6 and it seems correct too.

[Zermelo]

5 minutes ago, Stu said:

This is what SkySafari 7 has to say which seems to have been corrected? These are for the two dates of the OPs observations. It seems Zeta Herc is now in Hercules too 😉

Ah yes, thanks Stu.

All is right with the world in V7 - at least, for those on iOS!

 

 

 

[Zermelo]

3 minutes ago, Stu said:

@Zermelo which version of SkySafari were you using? Just checked 6 and it seems correct too.

I am on Plus, v6.8.6.3

[Mr Spock]

WDS has:

WDS STF2084
Component 1 magnitude: 2.950
Component 2 magnitude: 5.400
Separation: 1.3
Position angle: 134
Date: 2015.00
Spectral class: 1 G1IV 
Description: O BD+31.02884

And from Stelle Doppie:
""wds_name""    ""d_mag""    ""sep""    ""m1""    ""m2""
""STF 2084""               2.5          1.4         2.95        5.40

[Stu]

13 minutes ago, Mr Spock said:

WDS has:

WDS STF2084
Component 1 magnitude: 2.950
Component 2 magnitude: 5.400
Separation: 1.3
Position angle: 134
Date: 2015.00
Spectral class: 1 G1IV 
Description: O BD+31.02884

And from Stelle Doppie:
""wds_name""    ""d_mag""    ""sep""    ""m1""    ""m2""
""STF 2084""               2.5          1.4         2.95        5.40

That seems to match pretty well with SS.