28 replies to this topic

[AldebaranWhiskey]

I was intrigued by an interesting, though dated, article about the elusive, and apparently greenish, companion of Alpha Scorpii that I read in R. Burnham Jr.'s Celestial Handbook. Burnham states that it might be easier to view Antares' companion star during a lunar occultation when the companion emerges from the darkened limb of the moon before it's parent star, while the glare of the bright parent star is obscured by the moon. Has anyone ever observed this during an occultation?

 

I tried to view the companion sporadically this summer with no luck. I used powers from 40x up to 333x with no luck. At lower powers and naked eye Antares appears orange with a hint of oscillating blue and white. At higher powers (>100x) the colors incorporate green and red into the oscillation. The colors may be a product of viewing the star so low to the horizon at my latitude, that atmospheric interference is playing a large role in the appearance of the star. I assume that it may be easier to split the pair while viewing near or south of the equator.

 

My main questions are:

1. At what power(s) have you successfully viewed Antares' companion?

2. What colors did the two stars appear?

3. At what latitude did you observe them?

4. What was the P.A. of the companion?

5. About how far from the parent was the companion (minutes/seconds)?

 

Thanks!

Edited by AldebaranWhiskey, 16 September 2016 - 02:39 AM.

[cildastun]

I was intrigued by an interesting, though dated, article about the elusive, and apparently greenish, companion of Alpha Scorpii that I read in R. Burnham Jr.'s Celestial Handbook. Burnham states that it might be easier to view Antares' companion star during a lunar occultation when the companion emerges from the darkened limb of the moon before it's parent star, while the glare of the bright parent star is obscured by the moon. Has anyone ever observed this during an occultation?

 

I tried to view the companion sporadically this summer with no luck. I used powers from 40x up to 333x with no luck. At lower powers and naked eye Antares appears orange with a hint of oscillating blue and white. At higher powers (>100x) the colors incorporate green and red into the oscillation. The colors may be a product of viewing the star so low to the horizon at my latitude, that atmospheric interference is playing a large role in the appearance of the star. I assume that it may be easier to split the pair while viewing near or south of the equator.

 

My main questions are:

1. At what power(s) have you successfully viewed Antares' companion?

2. What colors did the two stars appear?

3. At what latitude did you observe them?

4. What was the P.A. of the companion?

5. About how far from the parent was the companion (minutes/seconds)?

 

Thanks!

My latitude is 52 degrees N, so splitting Antares is a challenge here (Oxford UK). The window of opportunity to see Antares is limited, and excellent seeing is required.

 

Best split I've had has been with a small ED80 frac on a portable mount, so I could move it to a nearby field, shoo off the horses, and get a totally clear view of the southern horizon. Best magnification was x100, giving an orange red primary and green/blue secondary, with PA and Sep as in CDSA. A few nights later, when the star had cleared a tree slightly more (but seeing slightly poorer), I also got a fairly good view from my garden with my 180 Mak,albeit slightly less contrasty.

 

For me, the issue (30 years trying to see the companion) has been waiting for a very good night, with excellent seeing and very little star twinkle.

 

Chris

[Redbetter]

I have split Antares off and on this year despite relatively poor seeing around 37 N, typically with the 20" because that is what I use most often, but also with a 10" and 8" earlier when the seeing was a little better.  What I saw at GSSP and typically experience at sites in the Central Valley and in the mountains is that there is some still air for an hour or so before and an hour or so after sunset.  This can provide some seeing that might rise to mediocre.  I find mediocre is good enough for Antares, but it is subtle.   If you haven't seen it split before you might not recognize the companion so close to the glare.  After the window of opportunity the breeze picks up with air masses heading down the mountains and valley and the seeing deteriorates.  That first bit of breeze is accompanied by reduced seeing in my experience (and I hop from scope to scope and ask others to make sure it is not just me or one scope.)   Twinkle of the stars also provided confirmation it isn't the scopes, or thermals, it is the seeing.  It gets worse as the breeze gets stronger and turns to wind.

 

By comparison in East Texas at 32-33 degrees I could split it with my 8" SCT regularly and I didn't consider it difficult.  I don't see aperture as a major limitation.  Good collimation and good optics help, but the primary factor is decent seeing.  Poor seeing will make it impossible as Antares' light will be spread over several arc seconds and swamp the companion with glare.

 

I don't recall specific measurements of PA on Antares, I typically don't measure them with the Dob, although I have others at times.  The equatorial mount on the SCT makes it easier there.  Washington Double Star catalog listed PA as 277 degrees and separation as 2.6".  Looking at my handmade PA wheel I mount on the Dob focuser when I do try to measure, that is about the angle I typically spot the companion, basically to the left and a little down from center when the star is on the meridian.  Visually the companion is very close because it appears so small compared to the bright and bloated (due to seeing) Antares.   Around 200x is sufficient for the split.

[Jon Isaacs]

I am at about 33 degrees north, culminates at 30 degrees, your 6 or 7 degrees north of me so Antares never is more than about 23-24 degrees above the horizon, that's quite low for splitting a double.  It still may not be too late in the year if you catch it as soon as you can after sunset.  

 

This summer I had many good splits of Antares, The seeing was quite good and with Saturn and Mars nearby, they made an interesting trio for higher magnification work.  The best splits were at about 250x in my 120mm ED refractor, 410x in my 10 inch Dob. With the Dob, thermal equilibrium is the big thing, it needs to be fully cooled, I have a sealed back fan that cools the scope, it takes at least an hour.. 

 

As far as the separation of Antares, Sky Tools 3 lists it at 2.02 arc-seconds and it is a short period binary whose separation changes slowly, in 2000, Sky Tools says the separation was 2.33 arc-seconds. 

 

Jon

[Bonco]

From 30 deg North, I usually can view it with my 4 inch refractors. Occasionally with my 3 inch. They are always orange and green when I see them.

Bill

[Magnus Ahrling]

Chris,

Surely I am impressed you have split Antares A-B at 52 N. Same as you I have tried Antares but from Southern Sweden at 57N. for the latest 30 years but no chanse with my scopes. C80ED-8"f/6 OOUK Newt. It´s just too low above horizon for a decent view. Actually have not read any report of anyone up here who has split Antares. If anyone have split Antares at 57N. it would be nice to know.

AldebaranWhiskey: I Think the most critical issue is from what alt you are observing...

Jon: Nice to read you got the best split this summer of Antares with the magnificent 120ED:-)

Magnus 57N.

Edited by Magnus Ahrling, 16 September 2016 - 06:56 PM.

[cildastun]

Chris,

Surely I am impressed you have split Antares A-B at 52 N. Same as you I have tried Antares but from Southern Sweden at 57N. for the latest 30 years but no chanse with my scopes. C80ED-8"f/6 OOUK Newt. It´s just too low above horizon for a decent view. Actually have not read any report of anyone up here who has split Antares. If anyone have split Antares at 57N. it would be nice to know.

Magnus 57N.

Magnus - I am lucky  I live in an area with views across open agricultural fields to the south; this area (central UK) is also very dry by UK standards and blessed very often with excellent seeing. It has taken many years though for the conditions and circumstances to be right.....

 

Chris

[fred1871]

Regarding Jon Isaac's comments above, about Antares as a binary - no, it's a VERY long-term binary, premature attempts at an orbit calculation suggest 1,000 years plus, and it does not noticeably change in a decade or two.

 

Current WDS lists a 2014 measure of 2.57" separation. That's much the same as 10 or 20 years ago. Antares has been frequently measured, and as usual with difficult doubles the result is a fair scatter of measures around the true numbers. Not everyone does a good measuring job. I would suspect the two separation measures Jon quotes are examples of this scatter.

 

My own easiest (and best) view of the companion of Antares, looking suitably green in contrast to the reddish primary, was years ago with a 7-inch apo refractor at only 100x - a very steady atmosphere, the Antares image more stable and less spread than usual, and the companion a small bright point beside the primary. It's rare to get conditions like that. It remained beautiful with some increase of power. I was surprised to see the pair so readily with such modest magnification.

[Stargazer713]

I had no luck splitting Antares this summer as seeing conditions were generally crappy. A couple of years back I was able to split this double under great seeing using an 80mm refractor. Primary of course was red and secondary believe it or not actually had a greenish tint to my eyes. Secondary was moving what appreared to be due west PA 270 as Antares drifted out of my eyepiece. I think key to splitting is seeing and viewing early in evening to limit the brightness of Antares.

[AldebaranWhiskey]

Well now I don't feel so bad not seeing it this year if some of you have been trying for many years.

It does seem like seeing is the major factor. I have been trying to split them with and 8" reflector from 40 deg N.

 

Most of the time I try pretty early in the session, usually well after dark. I will try some of the advice you all have given, like letting the mirror cool down longer and giving it a shot just after sunset when the glare of the primary isn't so overwhelming. At mag ~ +5.5, the secondary should be visible in a twilight sky. I might also try viewing from a higher elevation. I wonder if a moon or color filter would help, by bringing down the brightness, or showing more contrast? I have never actually tried filters on multiple stars.

 

Redbetter, I may have to take my scope with me the next time I visit family, they live in the Central Valley as well, several degrees south of me.

 

I will try again this week, though I may be running out of time for this year, it is already so low in the sky after sunset.

Thanks for sharing your observations and advice everyone!  

[Rich (RLTYS)]

It took me years of trying to split Antares but once I did it and knew what to look for it was fairly easy as long as seeing was good.

 

Rich (RLTYS)

[zwhzjh]

Hi,

The trick to make splitting Antares B (maybe we can call it little scorpion just to match Sirius B, the pup  ) easier is to use blue filter to reduce the glare of Antares.  This was what I used to accomplish the mission this summer although the seeing condition was not as excellent as that in the winter when I saw Sirius B.  Based on calculation, you will have about 5-second window to see Antares B using lunar occultation, almost impossible if you don’t have any experience.

Here is the answer to your question.

1. x360
2. A- red, B-white blue.  This is the reason why blue filter works.
3. 34N, so the altitude of Antares is 30 degree during transit.
4. around 275 degree.  This is based on my observation, and it is close to the value in Burnham’s handbook.
5. about 3 arcsec.

Good luck next summer! (Now Antares is too low right after sunset)

[Ziggy943]

Seeing is the key at N40.5°. I find that going to altitude gets better seeing for difficult double stars. I didn't get into the mountains this year with a telescope but did split it several times from what is basically the average 4200' elevation locally. The splits were not easy, not like going above 10,000 feet. So for me the key is better seeing through higher elevation.

Edited by Ziggy943, 01 October 2016 - 09:59 PM.

[SimonLowther]

I got a few great splits of Antares this year, and had no luck on a few nights with a 10" SCT, using 178 - 250X.

 

The nights I can split it at 250X I can also then see it at 178X with no difference in detection; I think seeing is the biggest factor.  Once you see it the first time it just pops out each night subsequently.

 

It looks green to me, but probably only because I was preconditioned to see it green; I am sure that if I had of read nothing of its appearance  before observing I would describe the colour as some shade of off white but who knows.

 

I am at 37S

[Bonco]

Looks very green to me. Pretty sure I saw it that way before I read about it.

Bill

[Rich (RLTYS)]

To me it looks emerald green.

 

Rich (RLTYS)

[dave brock]

Looks green to me as well.

Pretty easy most nights in my 20" and 10" dobs but then it passes almost at the zenith here.

 If your scope has any coma at all then it's better to not have Antares in the centre of the field but position it towards the edge of field where any extra light tends to be flared away from the companion. Hope that makes sense.

 

Dave

[larrytOMC200]

Hi, I tried for years (decades) to split Antares from my 54N site in the UK without success. (from about 16 years of age). I decided to give it another go after moving to NZ. On the 29th July this year I finally bagged it (now in my med 60;s). So Yay!! It was seen through my 12.5 obsession dob, the seeing was superb. (as an aside I had the best view of Saturn I ever had that nighthrough the dob).  I was well pleased I finaly nabbed it. Keep trying and clear skies

[noisejammer]

I managed it many years back from a friend's farm near Alldays, South Africa. We used her 12" LX200 and a dark blue filter. If memory serves, we were using a 14mm eyepiece, so around 220x. I've no recollection of the pa or separation except that it wasn't particularly challenging.

[leonard]

Hello,

 

 

                    One of the first doubles I ever tried to split . Used a 4 inch refractor at 135X and the seeing was 

Pickering 7 ish .   The secondary set on the first defraction ring , greenish in color . Just so cool to look at.

Done from Maryland east of Baltimore .

[SeaBee1]

From my notes of 8/20/2017, logged at 22:00, using my ATM 10" f/5 with Royce conical, 1mm exit pupil:

 

89* F, seeing 4/5, transparency 4/5, new moon, dew point of 74* F, RH 67%.

 

"Difficult split. The companion star is ~2" from the bright red Primary, and under most conditions, considered not splittable due to the flaring brightness of the Primary. I have attempted (unlogged) to split this one in the past, unsuccessfully. Conditions tonight were very good and I was able to detect the companion between the two left diffraction spikes from the scopes spider assembly. There was minimal flaring of the Primary."

 

I am at 33* N latitude. I am not sure why I did not note the color of the secondary, the magnitude of the components, nor the PA, except I am very new to this pursuit of doubles, and the reporting protocols. Fun stuff none the less!

 

Clear skies!

 

CB

[Karl Fabian]

Usually Antares is a mess being too low from my latitude 42 deg N.. However back in September the seeing was good enough to finally bag it after many attempts over the years. Seeing is the key to resolving this double. In my refractor the contrast was stunning! Component was a vivid green in my 5 inch.

 

https://www.cloudyni...ro/?hl=+antares

[Asbytec]

I did not realize Antares was a nice double until I was focusing on it tonight and noticed a dim star just west of it. (P.A. 277.4 SEP 2.56 MAG 0.96,5.40) Quite nice looking, it was an easy split at 37 degrees above the horizon. I was using my 8" at 400x under some transparent overcast skies and pretty good seeing. Ran across this thread when I was looking for info on it. I did not notice much color in the companion, just a tiny dim speck. The skies were a bit cloudy, so... 

[Scott in NC]

Norme, I see you're somewhere around 15°N latitude, so it appears that you were treated to a good view of it that those of us in the U.S. and Europe don't have the luxury of ever getting.  Thanks for sharing your observations with us!

 

And thanks for bumping this old thread back to the top of the list again.  Reading this has inspired me to give it a try again!

[Asbytec]

Scott, yes, Antares rides a little higher down here. Nice thread.