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Antares Challenge


John
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 The clarity of the atmosphere is certainly affecting your chances of splitting Antares in the UK. It is a credit to any of you who succeed with it at such low elevations. My view of it here in Melbourne with the star at about 60 degrees elevation was steady as a rock, no drifting in and out at all. E and F in the Trapezium likewise is fairly easy with Orion also at 70 degrees up.

I get into difficulties with splitting the Double Double which cruises along just above our northern horizon, I have managed it but seeing all four is a tough challenge through the haze.

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6 hours ago, David Levi said:

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.

I've done it in the past with an 80ED - I don't think aperture is the main issue really, it's more about seeing and as John says, having a clear S aspect (and of course having any clear nights).

This is a simulation (Aberrator) of Antares with a 180 mm Mak and a 100mm frac - you can see both can split it easily; I've added a bit of colour for fun!

Chris

 

antares - Effect of aperture.jpg

Edited by chiltonstar
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6 minutes ago, chiltonstar said:

I've done it in the past with an 80ED - I don't think aperture is the main issue really, it's more about seeing and as John says, having a clear S aspect (and of course having any clear nights).

That's good to know. My location isn't great for low declination observation. SQM is roughly 19.0 at the zenith and of course there's a lot more muck to look through low down on the horizon.

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1 hour ago, chiltonstar said:

I've done it in the past with an 80ED - I don't think aperture is the main issue really, it's more about seeing and as John says, having a clear S aspect (and of course having any clear nights).

This is a simulation (Aberrator) of Antares with a 180 mm Mak and a 100mm frac - you can see both can split it easily; I've added a bit of colour for fun!

Chris

 

antares - Effect of aperture.jpg

Thanks for that Chris. If those position angles are right then that builds my confidence more that I got the split. I'd say that last night the secondary looked a smaller blob than the primary and rather more the colour of dirty blu tack !

It was good to be observing something last night, I've not been out much due to the poor weather lately.

 

 

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11 minutes ago, John said:

Thanks for that Chris. If those position angles are right then that builds my confidence more that I got the split. I'd say that last night the secondary looked a smaller blob than the primary and rather more the colour of dirty blu tack !

It was good to be observing something last night, I've not been out much due to the poor weather lately.

 

 

The Stelle Doppie figure for PA is 277 degrees which matches what we both saw I think. The blue of the secondary may be aperture dependent as I would say with 180mm it was definitely blue-green 'ish, although of course with atmospheric refraction and seeing wobbles, colour is always a bit subjective!

On my original, the intensity ratio looks right, but shrinking the file and copying across has made the intensities look more similar. Unfortunately, my laptop was also trying to perform a couple of updates (G knows what) which corrupted the image file slightly. This is the 100mm simulation with the blue-green intensity reduced to something more like the correct ratio (it makes the colour slightly more Blu Tack'ish maybe?):-

Chris

antares 100mma.jpg

Edited by chiltonstar
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"....with atmospheric refraction and seeing wobbles, colour is always a bit subjective!...."

It most certainly is !

That image is close to what I observed in terms of scale and hues during the moments of best steadiness, which were rather few of course. The kaleidoscopic effect of the atmosphere on the primary star was doing it's best to keep the secondary a secret :rolleyes2:

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10 minutes ago, chiltonstar said:

This is the 100mm simulation with the blue-green intensity reduced to something more like the correct ratio (it makes the colour slightly more Blu Tack'ish maybe?

That's pretty much how they looked to me, maybe the secondary was a tad brighter here and more grey/green, but pretty close.

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I went out with the intention of having a go at Antares last night but cloud stopped that plan. I did split the double double and then Izar with the Equinox 80 and Nagler Zoom. I hadn’t expected to get Izar in the frac and was very pleasantly surprised. Chris’ comments on splitting Antares at 90x gives me hope of getting a split with this setup. 

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  • 4 weeks later...

Pleased to report a split with my Tak FC-76 at 90x, which just revealed the tiny grey-green secondary. Seeing was exceptional and Antares was at about 75-80 degree altitude. Which clearly helped a lot...

 

However, a second attempt a few days later ended in failure. Better transparency but poor seeing and I could not see the secondary even at almost 200x, with the primary dancing all around. Was a night for DSOs.

 

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  • 1 year later...
Posted (edited)

Older thread revival !

I've just managed a split of Antares with my 100mm refractor. Position angle and relative brightness of secondary star looked correct. Given it's low altitude here I was surprised tonight how steady and well defined the image of Antares was. The secondary star (magnitude 5) looked very dim by comparison. The split is 2.6 arc seconds but it is the low altitude and major brightness difference between the stars that makes it such a tricky split. The mag 5 star was approximately due west of Antares.

Nice result and not one I was expecting :smiley:

Edit: should have also mentioned that I was using 225x and 257x magnification.

 

 

Edited by John
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Excellent! Every time I tried Antares last year the seeing was hopeless, but I should give a try this weekend, it looks like a good calm spell.

I'm thinking  to use the 127 Mak, instead of my 180 Mak, it's more resistant to seeing and the 120mm aperture should be sufficient. Antares  reaches only 11 degrees altitude for me, so it will be all down to the seeing.   

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1 hour ago, Nik271 said:

Excellent! Every time I tried Antares last year the seeing was hopeless, but I should give a try this weekend, it looks like a good calm spell.

I'm thinking  to use the 127 Mak, instead of my 180 Mak, it's more resistant to seeing and the 120mm aperture should be sufficient. Antares  reaches only 11 degrees altitude for me, so it will be all down to the seeing.   

It's not much higher here (North Somerset).

I have to catch Antares in a gap between the houses and trees. I have tried a few times over the past weeks but the image was "boiling" too much. Last night it was surprisingly calm.

 

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I wonder if a blue filter will help, it will dim the orange primary while (as far as I know) the secondary is blue.

Edited by Nik271
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Antares is to me a bright red / orange kaleidoscope. 

Possibly due to having Derby directly to my south and close by, so i have to see

through all the pollution and plumes coming off it. M4 though, makes a good second prize.

Its one i try for every season (like Sirius !) but no luck so far. The same story with Trap E, F stars i'm afraid. 54 year old eyes don't help much either.

I'd love to be able to study Scorpius and Sagittarius in detail as they are my favourite constellations, but its not to be i'm afraid.

 

 

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Forecast is good for tonight John here, so will give it a try with my 102mm ED f11 scope with new 4mm Delite Televue EP. Fingers crossed! I’ll report back how it goes! 🤞🏻🤞🏻🤞🏻

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Posted (edited)

No-go here tonight with Antares :rolleyes2:

I'm using the 120mm refractor but the seeing is just not up to it. Antares is a glimmering ball rather than the neatly defined star it was last night.

The consolation prize was Messier 4 though. Near Antares, a nice bright globular cluster which starts to resolve to stars quite easily even with smaller aperture scopes. This globular has a distinctive band or bar of brighter stars running through it. It is the closest globular cluster to us at around 5,000 light years distance. Messier 4 is very old though - around 12 - 13 billion years old in fact. About as old as anything can be !

Short session tonight - up early tomorrow :rolleyes2:

This sketch of M4 is by Michael Vlasov:

m4-sketch.jpg.4961aa49848e972507292990a1b883cf.jpg

Edited by John
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I tried with my 127 SW Mak at about 11pm. Sadly the air that low was very turbulent, Antares was sparkling in all colours of the rainbow.

I checked  Izar and the Double Double and got superb clear views even at 250x, so the seeing higher up was good. I think Antares requires a vacation in middle East or thereabouts. Some dry desert air and no light pollution. We can dream :)

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1 hour ago, Nik271 said:

I tried with my 127 SW Mak at about 11pm. Sadly the air that low was very turbulent, Antares was sparkling in all colours of the rainbow.

I checked  Izar and the Double Double and got superb clear views even at 250x, so the seeing higher up was good. I think Antares requires a vacation in middle East or thereabouts. Some dry desert air and no light pollution. We can dream :)

I've managed it a couple of times in the past from near Oxford Nik, but not so far this year. It needs one of those very exceptional evenings. But maybe a holiday somewhere S of 30 degrees N is a better idea than waiting.....

Chris

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I have done it in the past with my 115mm APO and my M/N 190, but with the star 23 degrees above the horizon, much easier than in the Uk. Conditions are everything with this and of course Sirius.

Alan

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Tried last night with my 102mm Ed f11 ‘frac with 4mm Tele Vie Delight EP. Even pushed magnification with a 2x barlow also. Whilst I could see that there were two pairs of stars with nice contrasting red and green colouring, the seeing didn’t allow a clean split, although I could make out a figure of eight when seeing slightly steadied somewhat. At highest for me Antares is only just under 10 degrees above the horizon, so it may prove impossible to do at all except for that one elusive steady clear night that might assist in allowing a clean split.

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