Antares, again

It's been awhile since I've done it, but whats
the minimum scope/aperture/magnification you've
used to split it?
If I were to rate three pairs that increase in difficulty
in terms of splitting them, I'd pick:
Rigel
Antares
Sirius
-Rich

Richard wrote:
It's been awhile since I've done it, but whats
the minimum scope/aperture/magnification you've
used to split it?
If I were to rate three pairs that increase in difficulty
in terms of splitting them, I'd pick:
Rigel
Antares
Sirius

You can probably stick Procyon near the end, there, too.

Ahh, have I split Antares? I can't say that I have. I've only tried
on two or three occasions, though, all with Antares near the horizon.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

On Wed, 1 Sep 2004 00:17:27 +0000 (UTC), Brian Tung wrote:

Richard wrote:
It's been awhile since I've done it, but whats
the minimum scope/aperture/magnification you've
used to split it?
If I were to rate three pairs that increase in difficulty
in terms of splitting them, I'd pick:
Rigel
Antares
Sirius

You can probably stick Procyon near the end, there, too.

Ahh, have I split Antares? I can't say that I have. I've only tried
on two or three occasions, though, all with Antares near the horizon.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

I have also been taking advantage of the clear (for now) skies up here in
the northwest to attempt to split this tough double. Going out to try it
around 8:45 to 9:00 p.m. when the sky just dark enough to reveal the star
which is slightly to the west of the meridian, I am not having much luck.
I suppose the main reason for this is less than ideal seeing conditions and
fairly low proximity of Antares to the horizon. I am not sure exactly how
high it is but it seems to me that it is less than 30 degrees. I'd say
maybe 20 to 25 degees maximum. . .if that high. Also, I am using a 114 mm
with a focal length of 910 mm coupled with a 6 mm eyepiece. I realize that
the obtained 150x is probably insufficient for the job but I keep hoping to
see something at the anticipated position in the first diffraction ring's
zone.

Perhaps my 12.5 inch dobsonian could do the trick but I am hesitant to set
it up on nights around the full moon since DSO's after the attempt at
Antares would be out of the question.

Do you think the 12.5 would have any chance at splitting the double star
given its low position off of the southern horizon?

"Martin R. Howell" wrote in message ...

Also, I am using a 114 mm
with a focal length of 910 mm coupled with a 6 mm eyepiece. I realize that
the obtained 150x is probably insufficient for the job but I keep hoping to
see something at the anticipated position in the first diffraction ring's
zone.

I've done it at 150x in a 6" Newtonian, although it's much easier at
300x.

Perhaps my 12.5 inch dobsonian could do the trick

Its greater magnification should help.

Do you think the 12.5 would have any chance at splitting the double star
given its low position off of the southern horizon?

Splitting Antares is more dependent on seeing than aperture, but even
at low altitude and under somewhat poor seeing, I've managed to spot
the (sometimes bluish, sometimes greenish) Airy disc of the companion
superimposed on the huge, flaring mess of the main star. I think it
gets easier after you discover precisely what to look for.


- Robert Cook

"Brian Tung" wrote in message
...
Richard wrote:
It's been awhile since I've done it, but whats
the minimum scope/aperture/magnification you've
used to split it?
If I were to rate three pairs that increase in difficulty
in terms of splitting them, I'd pick:
Rigel
Antares
Sirius

You can probably stick Procyon near the end, there, too.

Ahh, have I split Antares? I can't say that I have. I've only tried
on two or three occasions, though, all with Antares near the horizon.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

I was going to suggest that as well. ;^)
Just wondering if anyone in saa has managed a split of Procyon. I mean, a 9
magnitude difference has got to be difficult to overcome.
Occulting bar?

Best regards,
Bill

Rich posted:

It's been awhile since I've done it, but whats
the minimum scope/aperture/magnification you've
used to split it?
If I were to rate three pairs that increase in difficulty
in terms of splitting them, I'd pick:
Rigel
Antares
Sirius

I don't know exactly how much power I used when I last attempted it, but it
was probably in the 150x to 250x range. I recall observing Antares during
twilight a number of years ago at the Nebraska Star Party, and with the 10
inch, it was not terribly difficult when the seeing was good. I then stopped
the scope down to only 94mm (3.7 inches) and still managed to just barely
resolve the double, although the companion was faint and nearly right on a
diffraction ring. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

In article , Richard wrote:
It's been awhile since I've done it, but whats
the minimum scope/aperture/magnification you've
used to split it?

I've split it several times with my 8" SCT which has mediocre
optical quality. Mostly I can't split Antares at all though;
it depends mostly on the seeing at its (usually low) altitude.

I think T. W. Webb's classic "Celestial Objects for Common Telescopes"
mentions Antares as being splittable in a 3" refractor -- but again
mainly as a test of seeing (i.e. turbulence, not darkness nor transparency).

If I were to rate three pairs that increase in difficulty
in terms of splitting them, I'd pick:
Rigel
Antares
Sirius

One star I'd really like to see split again is Zeta Herculis.
It's a rather short-period binary -- 34 years -- with 2.5-magnitude
difference. Once, just once, in the mid-1990s when the separation
was about 1.5 arc seconds, I managed to split it with my 8" SCT.
It looked like a miniature eta Bootis, with lovely bright gold and
bluish components. It was a hot, extremely still summer night.

It's closer now, about 1 arc second and widening.
It might be within reach of a *good* 8" in very steady skies in the
next year or two.

I don't know whether Zeta Her deserves to be considered easier than
Sirius or harder...

Stuart in steamy Champaign, IL

...difficulty
in terms of splitting ...

Rigel?


john

(Izar187) wrote in message ...
...difficulty
in terms of splitting ...

Rigel?


john

John, I agree. Rigel is a very easy split in just about any decent telescope.
Maybe Zeta Orionis?

John, I agree. Rigel is a very easy split in just about any decent
telescope.
Maybe Zeta Orionis?

Rigel is way too easy. My 15 year old son likes nu scorpii (all 4) and
delta cygnii for a bit of a challenge with a homemade 6" f/8 dob. However,
I know that we have never split Antares, though I think I have read of
others finding success with good 4" refractors and 120x. My younger son
(12) recently completed a very nice 5" f/11.4 mirror, and he is hopeful that
it will prove a great splitter.

Dennis