Your 4 best double stars!!

[Liz]

Looking forward to hearing of your 4 favourite double stars, and why??
Have done a few searches, and while there are lists with many stars, I would like a more compact 'southern approach'.
thanks heaps

[Robh (Rob)]

Liz,

Had to do 5 and couldn't restrict it to just doubles. Then I thought of sigma Orionis. Better not go over-board! Didn't know what sort of detail you wanted but these are my favourites (in no particular order) ...

1. Almach (gamma Andromedae). Triple star system but only seen as two stars magnitudes 2.3/5, separation about 10". Striking contrast- yellowish orange and blue pair.
2. beta Monocerotis. Triple star mags 4.6/5/5.3, separations AB about 7" and BC about 3". All blue-white (B3) stars. Fantastic triplet.
3. 145 Canis Majoris (h 3945). Double star, magnitudes 5/5.8, separation 27". Striking orange and bluish pair.
4. Regor (gamma Velorum). System of four stars magnitudes 1.8/4.1/7.3/9.4, separations 41", 63", 94". Primary is the brightest known Wolf-Rayet star. Has the nice shape of a capital Y.
5. Albireo (beta Cygni). System seen as two stars magnitudes 3.2/4.7, separation about 36". Famous orange and blue pair.

Furthest north is Almach at about +42 degrees declination.
Regards, Rob

[Liz]

Thats fantastic, Rob, just what I wanted ..... thank you!!

[Coen]

Doubles I like to show people:

1. Alpha Cent - 79.9 year orbit, roughly at their closest, plenty of miscel. info to chat about and can see the orientation change over a the years
2. Acrux - something about two essentially identical stars
3. Theta Ori - the Trap is magnificent and plenty to discuss regarding how it formed, what's role is at the moment, how it is tearing apart the nebula etc.
4. h 3945 for the colours - interesting to hear what people say they see

Lots of others for honourable mentions including:
Gamma Vir - it is openning up at the moment, changing quickly (relatively speaking)
Rigel - bright + faint in the diffraction ring
SDBL H27 - stumbled across this one in a nice star field
SDBL PZ 2 (Acamar, The Eri) - nice pair
Sigma Ori - lovely multiple with another almost mirror but fainter nearby
Lamba Ori - nice yellow/orange

[Enchilada]

1) Alpha Crucis DUN 122/123 - DUN 252*
2) Alpha Centauri Rch 1
3) x Velorum DUN 95
4) p Eridani DUN 5

[Liz]

Many thanks Coen and Enchilada

Any other great double we havent had mentioned??

[ngcles]

Hi Liz & All,

Originally Posted by Liz

Any other great double we havent had mentioned??

1. Alpha Crucis (Acrux)
2. Alpha Centauri
3. Theta Eridani (Acamar)
4. h3945 (Canis Major)
5. Dunlop 94 (Carina)
6. p Eridani
7. Gamma Arietis (Mesaritm)
8. Gamma Leonis (Algieba)
9. Beta Cygni (Albiero)
10.Beta Monocerotis (STF 919)

As you can see, I don't count well ...

Best,

Les D

[Enchilada]

Originally Posted by Liz

Many thanks Coen and Enchilada

Any other great double we havent had mentioned??

How about (no order...)

Upsilon Carinae / Rmk 11
Gamma Centauri * very hard
Antares / Alpha Scorpii
Theta Muscae / RMK 16 / DUN 129
Gamma Crucis / DUN 124
Mu Cru / DUN 126
Beta Muscae / R207 * very hard

[Enchilada]

Originally Posted by ngcles

As you can see, I don't count well ...

Nor me!

[Liz]

Originally Posted by Enchilada

Nor me!

I dont mind!!
Thats about 20 great double/multiple stars for our group to chase and enjoy!!
Thanks Les too.

[Rodstar (Rod)]

Great minds think alike. my favourites are:

h3945 in Canis Major, mags 5 and 5.8, sep 27, lovely colour contrast which I see as yellowy-orange and blue. Like a southern version of Albireo.

70 Ophiuchus, mags 4.2 and 6.2, sep 5, yellow and red double, interesting because it has a period of only 88 years, so if you track it over the years, you will see some change in PA

sigma Orionis, mags 3.7, 8.8, 6.6, 6.3, seps 12, 13 and 42, wonderful multiple system, with an added bonus, with Struve 761 - a triple star system in the FOV

Antares in Scorpius, mags 1 and 5.4, sep 2.5, deep orange primary, blue secondary (some see it as green but when I split it cleanly, it is blue to my eyes). A difficult target, needs very steady seeing, and larger aperture and high magnification helps a lot.

Adhara in Canis Major, mags 1.5 and 7.5, sep 7. Both stars look Bluish-white to me. They are a fabulous contrast of magnitudes, reminiscent of Rigel.

I would also add that just two days ago I finally received my copy of "The Cambridge Double Star Atlas". I ordered it a couple of months ago on FishPond, it is the second print run. I cannot say enough about it. As far as double stars as concerned, it provides a list of 133 showpiece double stars with lots of interesting detail on each, and then plots 2400 of the best doubles in the sky over 29 sky maps by Will Tirion, then has a further appendix with data for each of those 2400 double stars. The maps are (naturally given their author) superb. The maps also contain 900 deep sky objects, and stars down to mag 7.5, so it is actually an excellent general purpose sky atlas. I am planning to use this Atlas for observing near full moon time each month, it has opened up a wonderful new window for me. Up until now, I have never had a star atlas which plots AND IDENTIFIES double stars, so double star observing has been less motivating - but now I can do some star hopping and track down these gems, now that the doubles are plotted and identified.

My only criticism of the star atlas is that the position angles are not provided (sometimes these can help with identification for tight doubles).

Happy observing!

[dannat (Daniel)]

gamma Vel would be at the top of my list

Can we have a bino/small scope (<4") list & big scope list

[Robh (Rob)]

If you're after ones that are in the night sky now, I'll add ...

rho ophiuchi. On the border with Scorpius (it is only about 1.3 degrees from omicron Scorpii). On lower power looks like a wide triple in the shape of a delta wing aircraft. The central brighter star AB is a double as well, magnitudes 5/5.7, separation about 3". The wider stars C and D are magnitudes 6.8, 7.3 each about 150" away.

xi Scorpii. A bit more of a challenge to track down. Seen as a nice, very wide double double, separation 279". Brighter pair (STF 1998) are about magnitude 5 and 7.3, separation 6.3". Wider pair (STF 1999) have magnitudes 7.5/8, separation 12".

Regards, Rob.

[OneOfOne (Trevor)]

A number of people have already mentioned it, but for the kudos alone...you can't go past our next door neighbour, good ol' Alpa Cen! Surely by now the Robinson's must be there?

[Campus Dweller]

To all the others mentioned, I'll add Rigel, put in another plug for gamma-Arietis and, for something a bit more obscure, also mention a binary that can be found in the Orion Nebula region that I remember observing but I'm too lazy to get off my backside and go look it up.

Someone will probably know it

[Miaplacidus (Brian)]

For small telescopes, or for getting beginners interested, Beta Tuc (1 and 2) makes for quite a nice pairing. Especially since you can first point out to people how it forms a naked-eye (or binocular) "double" with HIP 2578.

I also like Ruby Crucis (DY Cru, I think), for demonstrating colour and variability, next to Beta Cru and in the same FOV as the Jewel Box. Does that count?

Then there's Acamar, in Eridanus, and then the coloured pairs listed elsewhere.

Nice thread.

Cheers,

Brian.

[ausastronomer (John Bambury)]

Originally Posted by Enchilada

3) x Velorum DUN 95

Without a doubt one of my favourites and unfortunately not very well known at all. For some strange reason it is neglected in a large amount of the literature, including Hartung's. IMO it is a better Yellow/Blue colour contrast double than Albiero (Beta Cygni).

Another that I like which I don't think has been mentioned is Gamma Delphinus. There are a couple of nice doubles in Bootes, including Epsilon. 24 Comae is also nice with a good colour contrast.

Most everything else that has been mentioned by others is pretty high up on my hit list.

Cheers,
John B

[Kevnool (Kev)]

Epsilon Lyrae the double double binary system in Lyra is great.
Most of the other southern jewels have got a mention.
Cheers Kev.

[Liz]

Thank you everyone!!
Think we all love double stars , and now we have a whole heap of great ones to choose from ... and a lot I have never seen before.

[Enchilada]

Delta 1,2 Apodis / BSO 22 is a simple wide 4th magnitude double 103 arcsec apart. An equal all year orange pair showpiece for any aperture. Sheer pleasurable southern gems - even in binoculars! (cute connotation)