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John

Antares Challenge

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Last year I managed to split Antares for the first time. It is a very challenging double star for three reasons:

- The separation between the 2 componant stars is around 2.5 arc seconds.

- The componant stars are markedly different in magnitude, the primary being magnitude 1.0 and the secondary magnitude 5.4.

- From the UK, Antares does not rise far above the horizon. Currently it's reaching around 12 degrees above the horizon from where I observe. Thats a lot of atmosphere to peer through.

The split that I got was with my 130mm triplet refractor at 300x. While there was quite a bit of distortion and scatter created by the low altitude of the star, the secondary star could clearly be seen to have greenish tints compared with the orange/red of the primary. While challenging I don't think it was quite as tough as splitting Sirius but it's not far off that. 

With Antares gradually becoming more favourably positioned at a reasonable hour now, I'm going to have another shot at it when a suitable opportunity comes along. Jupiter lies not far from Antares as well so another good reason to search out a clear southern horizon at around 1:00 am.

I'll be interested to hear of other folks Antares splitting exploits too :icon_biggrin:

Antares is quite a bit larger than the Sun as this diagram indicates :shocked:

antares_compared_to_sun.jpg.0eda4b972dced18c27025999f2c43e52.jpg

 

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Great post, John. I’ve so far failed to split Sirius but will spend some time this season on Antares. Sounds like a good challenge :) 

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Thanks for that John, you've given me another new target to observe. If it's slightly easier than Sirius B then I should have little trouble splitting them, especially as Antares gets very high here. 

Patiently waiting for clear skies here on the mountain, it's been 3 weeks or more now with persistent cloud. :(

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Some years ago, I tried to image this pair, but failed miserably. Maybe I'll give it another go.

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I have done it in the past John from a better position than yourself but it is far from easy even here. I used the m/n 190mm and rate it harder than Sirius.

Alan

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It might just about be visible from my current "Planetary spot" down the garden. 12 degrees is very low though!

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Well done.... challenge accepted....

 

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I've split the pair twice with my 180 Mak - not easy though. A neighbour has an annoying tree which gets in the way, but I have found a spot in a field with a low southern horizon which is ok. There are not many evenings though when Antares is in the right place, there's no low cloud, and the seeing is excellent or better!

Chris

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I've never split it. Well done John!

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Thanks for the responses folks - I've been clouded out for the past few nights so I'm dredging up old observations to discuss ! :rolleyes2:

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5 hours ago, MarsG76 said:

Well done.... challenge accepted....

 

I suspect it might be easier from Sydney, being a little bit higher ...

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36 minutes ago, Demonperformer said:

I suspect it might be easier from Sydney, being a little bit higher ...

Perhaps it is but would be good to see live.

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I know it is a bit of a cheat but I am heading down to an island off the coast of Mozambique so I will have a crack when I am down there.  My defense is I will only have a 3" aperture to assist me.  Trying to recall if I have ever even attempted it in the UK.

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Thanks for posting, that's a good one to have on the observing menu.

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I had a go at it last year with my Newtonian but it was like looking through a Kaleidoscope.

I should be getting my new refractor soon, so will have to reacquaint myself.

 

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John

Have Scorpio now rising about 8pm 

Living in an area of very little light pollution, point out Antares using laser pointer doing presentation primary schools, joeys and Cubs, Scout movement

Pointed out Scorpio to my neighbor other night, and she could not believe how much of the sky it takes up

Scorpio rises just behind Southern Cross, also known as CRUX, and Omega Centauri sits between the two

John

 

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Success! My first decent session for over a month, wonderfully cool clear evening and a good 4 hours observing to make up for lost time. After 3 hours of viewing everything and anything (mostly Leo and Virgo galaxies) waiting for Antares to rise above the trees to my east I finally got the chance to have a go at the split. Got it centred with the Baader zoom and then inserted the Morpheus 6.5mm giving 230x and there it was, clear as a bell, a clean split, bright yellow/orange main star and pale greyish green secondary.

With my new Skywatcher Planetary 4mm giving 375x the split was more obvious but lacked the sharpness of the Morpheus.

I would rate the split as easier than Sirius simply because of much less glare from Antares. 

Elevation of about 60 degrees also made for very steady and clear viewing which helps tremendously.

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Nice one Geoff !

Won't be like that from here - 10 degrees elevation means waiting for the star to appear in a gap between the surrounding house roofs :rolleyes2:

Glad you got it though :smiley:

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60 degrees ........wow! I split it again two nights ago, and I had to use a much lower mag because of the near horizon seeing - x90 gave the sharpest view of the blueish-green secondary, nearly due West of the primary.

Chris

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Still waiting for a clear sky here ...... :rolleyes2:

 

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8 hours ago, Demonperformer said:

And doesn't look like we shall have one this coming week either ...

Looks pretty poor unfortunately, at least we are not missing any long dark winter nights or any decent Solar activity. Feels like this summer isn't going to be anything like last year, early days I guess........

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Well now - got some clear skies at last and also managed to split Antares during it's pass between the house rooftops and some large chestnut trees. The secondary was intermittently visible almost due west of the primary as Chris / chiltonstar says above. I made a rough sketch to confirm the position of the secondary when it was popping into view. The pleasing thing about this split was that I was using my Takahashi FC-100DL at 225x (Nagler zoom at 4mm setting). Considering the low elevation of Antares this was a pretty credible performance from the 10cm Tak I think. The primary star was showing the effects of being viewed through a goodly chunk of the atmosphere but quite often the glare was well controlled enough to allow the fainter greenish-grey secondary star to show itself.

 

 

 

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Well done John. I feel a bit disappointed now as I've just come in after failing to split Antares with my Takahashi FC-100D. I tried to see the smaller partner star without knowing its location and after giving up and looking up its position I still couldn't see it or even imagine that I could see it. I was binoviewing at approx. 200x magnification. There was a bit of unsteady atmosphere at that magnification and the diffraction rings weren't helping. It was a fun challenge though and one I will return to now that your experience has shown that it is possible with a 100mm apo refractor.

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I'm sure it is possible with the 100DC David. The secondary star does come and go quite frequently as the seeing fluctuates and is pretty close in to the primary as well as being indistinct. 

To be honest I could not recall the position angle of the secondary before I observed tonight but I suspected that I was seeing something a touch N of due W of the primary when Antares popped into view from behind my neighbours roof. My "suspect" was just in front of the primary and a touch to the north as it drifted across my undriven field of view. I kept at it to catch the steadier moments and gradually became more convinced that I was really seeing the secondary star popping in and out of view.

I'd like to try this again from our society observatory site which has a much clearer southern horizon than I have at home.

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