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fred1871
professor emeritus


Reged: 03/22/09

Loc: Australia
Re: Separation Gamma Equ new [Re: Nucleophile]
      #5893536 - 05/31/13 01:44 AM

I should've checked the date of the last measure for 42 Ori - you've reminded me that I wondered about that back when I observed it a while ago.

Yes, it has been tightening slowly over time since discovery in 1848, though given its past history since discovery by WR Dawes, the tightening has been nearly linear (little change of angle) and pretty gradual. I don't have the full list of measures to hand, but those I do have suggest a big change since 1995 is unlikely.

Probably the separation, assuming roughly a continuation of what happened from 1848 to 1995, in the 18 years since 1995 has come down to 1.0".

If we take the 1848 measure (2.0") and 1995 (1.1") the average time for a reduction of 0.1" in separation is 16.3 years. If we take the period 1926 (1.6") to 1995 (1.1") then the average time for a reduction is 13.8 years. Slightly quicker. However even in my current data I can see some scatter in the measures, so the difference might not be of much significance.

So, if we assume 42 Ori is now at 1.0" (or 0.95" - and the 2002 measure of Gamma Equ was 0.96") we still have the problem that the Delta-m of Gamma Equ is 4.0 mags to 42 Ori at 2.9; and your experience, and Bill's, that Gamma Equ was a lot easier than 42 Ori.

I've observed 42 Ori and can only agree it's a very difficult double with moderate telescopes, even in very good seeing conditions.


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Nucleophile
super member


Reged: 05/24/13

Loc: United States
Re: Separation Gamma Equ new [Re: fred1871]
      #5893552 - 05/31/13 02:07 AM

It seems we need some more observers to look at these and report their results during the next cycle. It is curious--but that's what makes it fun.

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WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Separation Gamma Equ new [Re: Nucleophile]
      #5893619 - 05/31/13 03:28 AM

Interesting comments on 42 Ori - I had this year this few successful observations (due to an unbelievable lack of clear skies) that this one stucks in my mind: At ~210 pointed elongation of 42 Ori indicating the position of the companion like a hour hand on a watch. This may be one of the rare examples where a fainter companion is an advantage as with equal bright stars the position of the companion would have been not this clear, at least not with 140mm.
To give Gam Equ another try I have to wait for mid September but here I see not the slightest chance with 140mm and hope that I have come on peaceful terms with my C925 then.
Wilfried


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R Botero
Pooh-Bah


Reged: 01/02/09

Loc: Kent, England
Re: Separation Gamma Equ new [Re: WRAK]
      #6037894 - 08/21/13 08:50 AM

Has anyone had a chance to revisit this one already? I had very good seeing last night but with the Moon out in full swing and at low declination, I could not quite make this one out.

Roberto


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WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Separation Gamma Equ new [Re: R Botero]
      #6038222 - 08/21/13 12:03 PM

Not yet - but in a few weeks it will be in my field of view.
Wilfried


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R Botero
Pooh-Bah


Reged: 01/02/09

Loc: Kent, England
Re: Separation Gamma Equ new [Re: WRAK]
      #6062285 - 09/04/13 08:32 AM

Given the seeing I had last night and no moon I thought I would give this one another go. I have to admit I did not see it. There was perhaps a hint of bump in the primary's first diffraction ring (at 450x with my 6" f/7.5 refractor) - a bump that I could not attribute to seeing as the rest of the diffraction ring did not exhibit this at all - but it was not a clear split. It appears the good seeing will continue tonight so I will have another go...

Roberto


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Bill Boublitz
super member


Reged: 05/04/13

Re: Separation Gamma Equ new [Re: R Botero]
      #6095961 - 09/22/13 11:01 PM

Gamma Equ definitely "prime time" now. Have been awaiting... clouds, moon, you all know the drill. Hopefully next weekend...

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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Separation Gamma Equ new [Re: Bill Boublitz]
      #6095993 - 09/22/13 11:17 PM

Roberto keep us posted. Unless I luck out with cool weather good seeing Im done with challenging doubles till perhaps June next summer. I can still luck out even through November but it gets progressively more difficult.

Bill, like Roberto's efforts I look forward to yours as well.


Pete


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Bill Boublitz
super member


Reged: 05/04/13

Re: Separation Gamma Equ new [Re: azure1961p]
      #6104117 - 09/27/13 12:44 PM Attachment (59 downloads)

Friends, I was able to observe Gamma Equ last night for an hour and twenty minutes. The companion was resolved at x300, with x400 providing the best view. The image was consistent with what I observed last Fall, except I was observing it at higher altitude, as it crossed the meridian. Fred, the wide double you mentioned was just outside my 0.15 degree field. I did not see much yellow to it last night, probably due to the higher altitude. I have a crude illustration that should give an idea of what I'm seeing...

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Bill Boublitz
super member


Reged: 05/04/13

Re: Separation Gamma Equ new [Re: Bill Boublitz]
      #6104121 - 09/27/13 12:45 PM

Click attachment in above post to view. Thanks! ~Bill

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R Botero
Pooh-Bah


Reged: 01/02/09

Loc: Kent, England
Re: Separation Gamma Equ new [Re: Bill Boublitz]
      #6104295 - 09/27/13 01:52 PM

Great news Bill! Illustration is very nice also. I've had nothing but clouds for weeks now.

Roberto


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WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Separation Gamma Equ new [Re: R Botero]
      #6104433 - 09/27/13 03:18 PM

"Remarkably, the companion is dimmer than the diffraction ring artifacts, but consistently displaces the arc and can be held steadily in vision"

Remarkable indeed - delta-m between the central disk and the first ring should be with CO 0.28 about 3.5 while delta-m for Gam Equ is 4 so this conforms to the observation. To see a secondary sitting on the first ring being at the same time fainter than the first ring borders on magic. But if correct this position would indicate a separation of about 1.13" assuming again CO 0.28.
I fear I will not be able to verify this observation with my 140mm refractor although the secondary should sit near the first minimum of the diffraction pattern means Rayleigh but I expect this delta_m is a bit too large for such a small aperture. My current RoT calculator suggests 190mm aperture with 1.13" separation for Gam Equ - I will certainly try with 140mm but expect nothing (and will quit within a few minutes if not seconds if I see no chance for a resolution - I admire observers who are patient enough to observe a binary for half an hour or longer).
The delivery for the 200mm Dall-Kirkham with CO 0.25 (this scope should do it I hope) I ordered in spring has slipped to begin 2014 so I will have to wait for another year. But with this scope I will also be able to reduce aperture with masks down to 150mm with CO still less than 0.35 to get a confident estimation for the limit aperture for resolving Gam Equ.
Remains interesting.
Wilfried


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fred1871
professor emeritus


Reged: 03/22/09

Loc: Australia
Re: Separation Gamma Equ new [Re: WRAK]
      #6105004 - 09/27/13 09:55 PM

I'll agree with Wilfried's comments here. In particular, being able to see the secondary on the diffraction ring is remarkable given the relative brightness of ring and star. I'm planning another attempt on Gamma Equ, using a C9.25, the benefit being that the secondary star won't be on the first diffraction ring if it's now moved to ~1.13" as Wilfried calculates from Bill's observation. It should at that separation be outside the first diffraction ring for 235mm and CO ~0.37, so easier to see.

Some comments on the orbit might be informative here. First, of course, it will be good to see a new measure of Gamma Equ to discover what it's currently doing. That's the missing element at the moment; we don't have a recent-enough measure. Evaluating observations is therefore difficult, involving estimates, and orbit projections, etc.

The pair was consistently closing in the late 20th century, despite the outlier measure of 1994; the 2002 measure of 0.96" should be accurate to a high level; so ~1.13 would suggest the pair is widening again. That amount of widening appears possible in the 11 years since 2002, based on the difference between the Hipparcos/Tycho measures of 1991 and the 2002 figure.

The orbit of this pair appears to be seen nearly edge-on from Earth, given the small change in PA over 135 years of measures. Of course, it might be an artefact of the section of orbit so far seen - nearly linear, but starting to curve in recent times (implying it's less edge-on). The PA did appear to be drifting a little in the more recent period; after being around 275 for many decades, it had moved only to ~268 in 1958, but to ~264 in 1991 and 258 in 2002.

The increased rate of change in the more recent measures, in separation as well as angle, suggests the periastron section of the orbit. If so, it's a matter of how close the pair gets over what time period. An increase in separation to the present date, compared to 2002, is a surprise, suggesting a rather quick periastron period, perhaps with 2002 being near minimum separation. So it might be possible, if somewhat unexpected; again, a new measure would answer that question. The orbit is quite large - the distance, about 118 ly, combined with the movement history, suggests an orbital period of perhaps a few hundred years given the scale involved. Rapid change will be around periastron.

So, a useful observation, Bill. We'll see how repeatable it is by other observers, with other telescopes. It might turn out that you've got a "best possible" result for the aperture used. That's one of the problems of the unequal pairs project; we can expect a bell-shaped curve, where "best" can't be achieved, even 50% of the time in good conditions, by everyone - observer visual acuity for doubles varies a lot, same telescope, same night, etc.

Okay - it's time for the rest of us to attempt Gamma Equ again.

Edited by fred1871 (09/28/13 03:38 AM)


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Bill Boublitz
super member


Reged: 05/04/13

Re: Separation Gamma Equ new [Re: fred1871]
      #6105252 - 09/28/13 02:31 AM

The world is waiting...

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WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Separation Gamma Equ new [Re: fred1871]
      #6106308 - 09/28/13 04:54 PM

Quote:

.. I'm planning another attempt on Gamma Equ, using a C9.25 ...outside the first diffraction ring for 235mm and CO ~0.37...




Fred, I assume CO for your C925 is 0.383 as the mounting of the secondary mirror makes up for a CO of 90mm and this is probably already too high to be of good use for resolving highly unequal binaries like Gam Equ even if the compnaion is sitting in the second minimum. Looking forward to your report.
Wilfried
PS: May be you can ask Bill for a spell on your scope


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Bill Boublitz
super member


Reged: 05/04/13

Re: Separation Gamma Equ new [Re: WRAK]
      #6108500 - 09/30/13 12:27 AM

Wilfried,

Since you are the one who started this thread, I am elated to learn you will be able to give a "few seconds" of observing time to the subject, (once you have acquired the proper instrument), in ... 2015?

A true testimonial to your sincere interest in the topic.

Ever Onward...


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fred1871
professor emeritus


Reged: 03/22/09

Loc: Australia
Re: Separation Gamma Equ new [Re: WRAK]
      #6108615 - 09/30/13 02:42 AM

Wilfried, I'd intended observing Gamma Equ last night with the C9.25, but unfortunately my go-to mounting would not go where it was told, apparently due to a balance problem; and as the SCT needed collimation tweaking, I decided not to waste a steady night - so I set up the 140mm refractor (go-to worked very nicely with that).

And so to Gamma Equ - but, to give the conclusion first, without success. I made Gamma Equ my first double of the night, and at 285x and 400x there was no companion. Seeing was good, a little flickery, and motion in the first diffraction ring. I observed for a few minutes, changing eyepieces back and forth, so re-focusing as well.

I then went on to other doubles, and because of the good seeing, which improved over time, I looked at various difficult pairs that were on my list, equal and unequal.

I went back to Gamma Equ later in the night, when it was still at good altitude, and the seeing had improved further. On the second attempt I tried powers of 333x and 400x initially, both with Ortho eyepieces that give very little light scatter. No companion. 570x showed the same result, no companion. THe first diffraction ring still had some movement over time, and every now and then gave the impression of a star point as an isolated spot where the ring was, but watching over a few minutes at various powers it was clear that it was a seeing artefact.

So I'll go with the possibilities that at present, either (a) Gamma Equ is at ~1.13" but that's still too difficult for a 140mm refractor, even though it has widened since 2002, or (b) that Gamma Equ is closer than the 1.13" estimated by Wilfried - my observation doesn't tell us that, but is consistent with it.

The various other doubles I looked at between Gamma Equ observations, and following the second observation, showed pretty well. I got elongation on various very close near-equal doubles - 72 Pegasi at 0.6" (ephemeris 0.57"); STF 2597 despite Delta-m 1.1 at 0.6" (ephemeris suggests 0.65"); the short-period binary HO 296 in Pegasus, again delta-m of 1.1, at 0.5" in 2012 and with an ephemeris separation of 0.485" for 2013.75.

A more uneven tough pair was BU 249 in Aquila - mags 7.4 and 9.4, measured at 0.8" in 2008; 333x showed the close companion as an extension of the primary, confirmed at 400x. BU 693 in Aquarius also showed double - mags 7.6 and 9.9 at 1.0" - a 1991 measure, but it had shown no sign of changing separation over time.

The recently discussed DJU 4 (13 Vul) yielded as a neat uneven close pair at 333x, despite being on the first diffraction ring with 140mm. Mags 4.6 and 7.4 at 1.4".

So it was a good observing night, regardless of not seeing Gamma Equ as two stars. Various other pairs rounded out the night.


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WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Separation Gamma Equ new [Re: fred1871]
      #6108653 - 09/30/13 03:42 AM

Fred, congratulations - great observations with 140mm. In terms of RoT proposed aperture BU249 should be equal difficult with Gam Equ.

Bill, with locating and changing eyepieces up to the required magnification I certainly need more than a few seconds for a specific object. If the resolution is not instantly given I will then give it several tries with moving through the field of view and tweaking focus combined with hope for moments of better seeing - what seems then seconds for me due to high concentration will take may be at least 5-10 minutes (I am always surprised how fast time runs when I am doing a session) - but then I will move on regardless if successful or not as I can simply not maintain this high concentration much longer without spoiling the rest of my planned session. And I really admire observers who are able to keep their concentration on one object for much longer time. But you need not worry that I will not give Gam Equ the necessary time with my 140mm refractor and if I ever get the 200mm DK with 0.25 CO I expect Gam Equ anyway to show the companion without troubles. If not then further investigations are required.
Wilfried


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Bill Boublitz
super member


Reged: 05/04/13

Re: Separation Gamma Equ [Re: fred1871]
      #6108661 - 09/30/13 03:58 AM

Fred, am I to understand that (after your last diatribe) were unable to FIND Gamma Equ because of a "faulty go-to system" ?????? !!!!!! Get your head out of your... um.... Objective Lens.

I'm glad to hear the seeing was good. I leave you and your friend to your mutual admiration society. You guys are a riot!


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fred1871
professor emeritus


Reged: 03/22/09

Loc: Australia
Re: Separation Gamma Equ [Re: Bill Boublitz]
      #6108680 - 09/30/13 04:50 AM

You're misreading what I said and what can reasonably be implied. The go-to system was giving wrong positions for stars straight out of set-up. Putting in RA and Dec consequently would take it to a wrong (wildly wrong) position. So there was no point going on with the system in that unhelpful condition. By changing over I had a useful and useable system that allowed use of a good observing night.

What's needed now is for a lot of other observers to look at Gamma Equ and report on seeing it double, or not, and describe their circumstances (telescope, seeing, magnification, what they saw). Obviously, with a large delta-m and small separation, good air steadiness is one of the essentials.


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