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Old 27-01-2018, 09:37 AM
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The Mekon (John Briggs)
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The finest triple double in the sky?

For discerning observers only!

I mentioned this group when discussing the main star in NGC 6193 in the observation report section. It is quite close to NGC 6193 in Ara.

Just north of the 6193 complex, is a small triangle of stars spanning around 0.4 degrees of sky. This group consists of the following double stars

HD 150040 mag 8.5/9.5 @ 2.6"
HD 150083 mag 7.4/9.4 @ 1.7"
HD 149901 mag 8.0/8.1 @ 1.4"

You will need a magnification of around 200x to resolve this group combined with a field of at least 0.4 degree, so a Nagler or Ethos type eyepiece is essential. I have found the best views were through my 132mm CFF at 184x in a 5mm Nagler yielding a .44 degree field. All the stars were distinctly split.

I first noted this group with my AP 130EDT using a 4.8 Nagler (212x). It was a real jiggle to get the three double stars in the field, a little less magnification is to be preferred along with good seeing and excellent optics.

If there is a better triple double, I would really like to know about it.
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Old 27-01-2018, 11:07 AM
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Tinderboxsky (Steve)
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Thank you for your new thread John.

I have been eagerly anticipating your post on this triple double following your comments in your NGC 6193 thread. It looks very interesting on paper. I look forward to the opportunity to study it in detail.

I shall be patient for a couple of months until it achieves reasonable elevation in the late evening. I am more a late evening observer. Morning session are just too hard unless there is a must see transient event.
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Old 27-01-2018, 02:03 PM
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Quote:
Originally Posted by The Mekon View Post
For discerning observers only!

I mentioned this group when discussing the main star in NGC 6193 in the observation report section. It is quite close to NGC 6193 in Ara.

Just north of the 6193 complex, is a small triangle of stars spanning around 0.4 degrees of sky. This group consists of the following double stars

HD 150040 mag 8.5/9.5 @ 2.6"
HD 150083 mag 7.4/9.4 @ 1.7"
HD 149901 mag 8.0/8.1 @ 1.4"

You will need a magnification of around 200x to resolve this group combined with a field of at least 0.4 degree, so a Nagler or Ethos type eyepiece is essential. I have found the best views were through my 132mm CFF at 184x in a 5mm Nagler yielding a .44 degree field. All the stars were distinctly split.

I first noted this group with my AP 130EDT using a 4.8 Nagler (212x). It was a real jiggle to get the three double stars in the field, a little less magnification is to be preferred along with good seeing and excellent optics.

If there is a better triple double, I would really like to know about it.
Well you certainly have/had had some incredible scopes John.

I too prefer late nights ..not fond of 4am rises..

I really am looking forward to this John ..power , and a wide field needed simultaneously.

I may take some shots and post them , if good enough; something more of us should do. .This fabulous object looks like a top candidate for this..others just dont know what there missing out in this aspect of Astro.

And yes John.. may need Ethos or similar at 910 mm
bigjoe.
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Old 27-01-2018, 10:52 PM
Wavytone (Nick)
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Joe ,

That's a nice one as each of the doubles is resolved at 200X and all three fit in the field of a wide field eyepiece (in my case in the Santel, the eyepiece of choice is a 14mm SSW).

But there is a stranger example ... Castor https://www.space.com/21940-castor-star.html
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Old 27-01-2018, 11:31 PM
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Quote:
Originally Posted by Wavytone View Post
Joe ,

That's a nice one as each of the doubles is resolved at 200X and all three fit in the field of a wide field eyepiece (in my case in the Santel, the eyepiece of choice is a 14mm SSW).

But there is a stranger example ... Castor https://www.space.com/21940-castor-star.html
Indeed Wavy..

Castor is one that we only ever think of as a double..some like this are very interesting indeed and a sextuplet !.and yy Geminorum below Castor itself a double! So much more to this doubles caper.

"Fascinating"... as Spock would say.

bigjoe.
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Old 27-01-2018, 11:33 PM
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Quote:
Originally Posted by Wavytone View Post
Joe ,

That's a nice one as each of the doubles is resolved at 200X and all three fit in the field of a wide field eyepiece (in my case in the Santel, the eyepiece of choice is a 14mm SSW).

But there is a stranger example ... Castor https://www.space.com/21940-castor-star.html
Indeed Wavy..

Castor is one that we only ever think of as a double..some like this are very interesting indeed and a sextuplet !.and yy Geminorum below Castor itself a double! So much more to this doubles caper.

"Fascinating"... as Spock would say.

That beast of a Maksutov of yours should make short work of most of them!

bigjoe.
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Old 28-01-2018, 12:28 AM
Wavytone (Nick)
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Joe a 3"-4" refractor are fun, I agree, and there certainly is some merit in using smallish refractors upto say 130mm / 5" which are definitely more immune to poor seeing than say a C8.

But this scope is something else, as it its quite capable of 450X if the seeing permits and I have realised that if you choose a site where the surface airflow above the scope is laminar, you can expect good seeing quite often. Basically what this means is that you need to be on or close to (within 200m) of a ridge facing into the prevailing wind. Shipley Plateau is looking very attractive for retirement.

Cant anything about the jetstream, though.

I'm making a list of doubles in the range 4 to 0.5 arcsec to try in autumn, assuming the weather picks up in March.

Last edited by Wavytone; 28-01-2018 at 12:40 AM.
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Old 28-01-2018, 02:10 AM
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Quote:
Originally Posted by Wavytone View Post
Joe a 3"-4" refractor are fun, I agree, and there certainly is some merit in using smallish refractors upto say 130mm / 5" which are definitely more immune to poor seeing than say a C8.

But this scope is something else, as it its quite capable of 450X if the seeing permits and I have realised that if you choose a site where the surface airflow above the scope is laminar, you can expect good seeing quite often. Basically what this means is that you need to be on or close to (within 200m) of a ridge facing into the prevailing wind. Shipley Plateau is looking very attractive for retirement.

Cant anything about the jetstream, though.

I'm making a list of doubles in the range 4 to 0.5 arcsec to try in autumn, assuming the weather picks up in March.
Anything's better than the atrocious seeing lately in Sydney...and the clouds!

Yes I also am making a list and checking it twice..as Santa is want to do.

Already finding its true...the smaller refractor handles seeing better than big central obstructions of an SCT .

Indeed a good Maksutov has a small , almost negligible one ..and so performs like a big refractor once cooled...with outstanding resolution taking up to 90x per inch of aperture...Esp the famous Russian ones that are difficult to come buy or very expensive , and soo very coveted.

bigjoe.

Last edited by bigjoe; 28-01-2018 at 02:13 AM. Reason: Adding
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Old 28-01-2018, 12:21 PM
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The Mekon (John Briggs)
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Quote:
Originally Posted by Wavytone View Post
Joe ,

That's a nice one as each of the doubles is resolved at 200X and all three fit in the field of a wide field eyepiece (in my case in the Santel, the eyepiece of choice is a 14mm SSW).

But there is a stranger example ... Castor https://www.space.com/21940-castor-star.html
Thanks Wavytone for your input. But I cannot credit Castor as being a better example. I am speaking particularly of observable triple doubles. Castor does not fall in this category. There are certainly many other sextuple systems out there, most if not all will be unobservable in an amateur telescope, with perhaps the notable example of theta Orion - which does not fit the category "triple double"

I should add that this "triple double" is not a bound system in any way, merely an optical gem of the sky.

Last edited by The Mekon; 28-01-2018 at 07:11 PM.
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Old 28-01-2018, 01:12 PM
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One fabulous triple ..alas not triple double..is Beta Monocerotis..and its viewable on a clear night above us in Oz this time of year.. something to wet the apetite till we await the other Gem in N6193.

A Gem that will surprise many , even in small scopes...with an easy separation even in average seeing...see below..

bigjoe
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Old 07-07-2019, 12:27 PM
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Observing this triple double has eluded me for a long time. I have tried a few times but weather and/or other interruptions have defeated me. Last night the seeing was perfect but the transparency a little variable with a lot of moisture in the air.

The triangular asterism stands out nicely against the rich star field and is easily seen near NGC 6193.

At 100X, HD149901 was a very close resolved pair of equal pin point white spots. HD150040 was more difficult but I was just able to resolve the fainter companion. I could not resolve HD150083 at 100X

At 160X, all three doubles were resolved, although HD150083 was still very difficult. Perhaps a night with less moisture in the atmosphere would resolve this more easily. 160X was through my LVW5, giving a 0.41 degree FOV. This easily framed the triangular asterism.

As you say, John, it is certainly a fine sight to have all three resolved doubles in the same FOV.

Interestingly, given your musings re possible other triple doubles, late at night I tripped over another possible candidate in ARA only 1.5 degrees from your triple double. I say "tripped over” as I was exploring the rich star fields and open clusters in the area when I noticed a small knot of stars that stood out against the background star field and had a closer look. The three primaries span only 2.5 arc minutes and the more remote star in the triangle was a distinct orange/red.

SkySafari Pro lists these as:
HD 151082 (red giant) mag 7.21/8.14 @ 106”
HD 151115 mag 8.13/9.5 @ 3.8”
HD 151116 mag 8.15/8.21 @ 45.3

For this triple double candidate, the primary stars cover a much smaller area, but the companions are more widely spaced. Observing and resolving these double stars was problematic. The transparency was staring to fluctuate and deteriorate. Dew was now streaming off everything. It was time to pack up. So, no chance to have a close look.

Still, very pleased to have all last resolved your triple double.

Edit: having had another look at SkySafari Pro, there is some confusion in relation to the data for these companions. I’ll need to research a bit deeper to ascertain whether this a triple double candidate. The jury is now out in my mind. It all looked like a good candidate at the time in the cold and wet of the late evening!

Incidentally, there is yet another possible triple double very very close by. These are three of the stars in the small open cluster Hogg 22. The three stars are listed as double stars in SkySafari Pro but there is an anomaly in the listings for the companions. All three companions are listed as mag 11.5 sep 21.1” and at 232 degrees. Some more research needed! I did not try to resolve these as the conditions were not favourable given the stated mag 11 for the companions. The field view was very attractive with Hogg 22 and the very close open cluster NGC 6204 standing out against the rich star field.

Scope: Vixen NA140SS with LVW 5, 8 & 22 eyepieces.



Quote:
Originally Posted by The Mekon View Post
For discerning observers only!

I mentioned this group when discussing the main star in NGC 6193 in the observation report section. It is quite close to NGC 6193 in Ara.

Just north of the 6193 complex, is a small triangle of stars spanning around 0.4 degrees of sky. This group consists of the following double stars

HD 150040 mag 8.5/9.5 @ 2.6"
HD 150083 mag 7.4/9.4 @ 1.7"
HD 149901 mag 8.0/8.1 @ 1.4"

You will need a magnification of around 200x to resolve this group combined with a field of at least 0.4 degree, so a Nagler or Ethos type eyepiece is essential. I have found the best views were through my 132mm CFF at 184x in a 5mm Nagler yielding a .44 degree field. All the stars were distinctly split.

I first noted this group with my AP 130EDT using a 4.8 Nagler (212x). It was a real jiggle to get the three double stars in the field, a little less magnification is to be preferred along with good seeing and excellent optics.

If there is a better triple double, I would really like to know about it.

Last edited by Tinderboxsky; 10-07-2019 at 03:14 PM. Reason: Corrections
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Old 08-07-2019, 02:28 AM
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Hi John & All,

Here's another one that may interest some people. There are two other pairs in the same field as Theta Scorpii (2.0 & 5.3, 6.5" sep)-- Donner 849 9.5 & 12 sep 1.6" and Cape Observatory 537 10.4 & 11.8, sep 4". You could throw a handkerchief over them as they are just 10 arc-minutes apart all-up. Relatively simple splits with some disparity in magnitudes.
Haven't looked at them in many a long year.

Best,

L.
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Old 10-07-2019, 11:42 AM
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The Mekon (John Briggs)
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Steve,

I am really pleased you have made a successful observation of this triplet of stars - and at such a low magnification! Getting that magnification and the field is the trick with this target.
I am back at work at present (meant to be retired but keep going back to sea, must have it in my blood). I will check out the objects you have noted once home later in the month.
I will also have a go at the Ara triple double with my 7" masked 18". With a13mm nagler it will yield 156x so it will be interesting to see if I can separate the two tighter pairs.
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Old 10-07-2019, 02:57 PM
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Quote:
Originally Posted by Tinderboxsky View Post
Observing this triple double has eluded me for a long time. I have tried a few times but weather and/or other interruptions have defeated me. Last night the seeing was perfect but the transparency a little variable with a lot of moisture in the air.

The triangular asterism stands out nicely against the rich star field and is easily seen near NGC 6193.

At 100X, HD149901 was a very close resolved pair of equal pin point white spots. HD150040 was more difficult but I was just able to resolve the fainter companion. I could not resolve HD150083 at 100X

At 160X, all three doubles were resolved, although HD150083 was still very difficult. Perhaps a night with less moisture in the atmosphere would resolve this more easily. 160X was through my LVW5, giving a 0.41 degree FOV. This easily framed the triangular asterism.

As you say, John, it is certainly a fine sight to have all three resolved doubles in the same FOV.

Interestingly, given your musings re possible other triple doubles, late at night I tripped over another possible candidate in ARA only 1.5 degrees from your triple double. I say "tripped over” as I was exploring the rich star fields and open clusters in the area when I noticed a small knot of stars that stood out against the background star field and had a closer look. The three primaries span only 2.5 arc minutes and the more remote star in the triangle was a distinct orange/red.

SkySafari Pro lists these as:
HD 151082 (red giant) mag 7.21/8.14 @ 106”
HD 151115 mag 8.13/9.5 @ 3.8”
HD 151116 mag 8.15/8.21 @ 45.3

For this triple double candidate, the primary stars cover a much smaller area, but the companions are more widely spaced. Observing and resolving these double stars was problematic. The transparency was staring to fluctuate and deteriorate. Dew was now streaming off everything. It was time to pack up.

Still, very pleased to have all last resolved the triple double. So no chance to have a close look.

Edit: having had another look at SkySafari Pro, there is some confusion in relation to the data for these companions. I’ll need to research a bit deeper to ascertain whether this a triple double candidate. The jury is now out in my mind. It all looked like a good candidate at the time in the cold and wet of the late evening!

Incidentally, there is yet another possible triple double very very close by. These are three of the stars in the small open cluster Hogg 22. The three stars are listed as double stars in SkySafari Pro but there is an anomaly in the listings for the companions. All three companions are listed as mag 11.5 sep 21.1” and at 232 degrees. Some more research needed! I did not try to resolve these as the conditions were not favourable given the stated mag 11 for the companions. The field view was very attractive with Hogg 22 and the very close open cluster NGC 6204 standing out against the rich star field.

Scope: Vixen NA140SS with LVW 5, 8 & 22 eyepieces.







Thanks Steve, et. al. I had a crack at HD149901/HD150040/HD150083 last night, it what I thought were pretty OK conditions. I could split 149901 and 150083 at 150x, but couldn't split 150040 despite it having a slightly larger separation, even at 200x and 300x.



I also gave HD151115/HD151082/HD 151116 a crack. I'm still coming to grips with determining position angles in my dob, but it seemed like Skysafari has HD 151115 and HD151116 mixed up - 151116 seems to have a pretty easily split double at about 3.8",which is what Skysafari said 151115 should have been. The others were very widely spaced.
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Old 16-07-2019, 02:46 PM
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Re Triple.

Hi all, been a while..
Need to look at this in my
Apo or even my CPC 925 with a 13mm Nagler ..I could just get it in field with that at .4 degrees and near 181x..seeing, weather not the greatest ATM.
bigjoe
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Old 19-07-2019, 04:19 PM
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From a northern perspective, there's a triple double in Cygnus discovered by William Lassell in 1857 at 21 34 50 +32 04 30.

In this case, the three pairs are separated by only 1' to 2' and the individual pairs have separations of 12", 19" and 22" and magnitudes of 10.6/11.9, 11.8/13.5, 12.1/12.1. So, not really bright but easily resolved at low power in any scope that shows the mag 13.5 star. WDS has all the components.

Also a 21" pair of mag 11 stars is ~10' NE, so could be taken as a quadruple double!
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