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Separation Gamma Equ

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#51 R Botero

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Posted 27 September 2013 - 12:52 PM

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

Roberto

#52 WRAK

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Posted 27 September 2013 - 02:18 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

#53 fred1871

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Posted 27 September 2013 - 08:55 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.

#54 Bill Boublitz

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Posted 28 September 2013 - 01:31 AM

The world is waiting...

#55 WRAK

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Posted 28 September 2013 - 03:54 PM

.. 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

#56 Bill Boublitz

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Posted 29 September 2013 - 11:27 PM

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...

#57 fred1871

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Posted 30 September 2013 - 01:42 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.

#58 WRAK

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Posted 30 September 2013 - 02:42 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

#59 Bill Boublitz

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Posted 30 September 2013 - 02:58 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!

#60 fred1871

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Posted 30 September 2013 - 03:50 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.

#61 WRAK

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Posted 30 September 2013 - 05:29 AM

... I leave you and your friend to your mutual admiration society. You guys are a riot!


Come on Bill, relax a bit. You did a great job observing Gam Equ and I take your report as serious positive even if I made more or less funny remarks concerning magic (I still can not understand how it is possible to resolve a companion sitting in the first ring being fainter than the ring but I will investigate this topic anyway) and duration of observation.
I apologize if this offended you, was not my intention.
Wilfried

#62 David Gray

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Posted 30 September 2013 - 11:02 AM

I have been following this thread with interest these past months, with the 415mm (16.3"),f/16, Dall-Kirkham Cass: 19% CO and decided to give the star some scrutiny in recent weeks.

What came out of it I find quite perplexing: several times it was “Yes!!!” then back came the uncertainties. There was usually more certainty with the apodizer applied; and one near-certainty with the 6” off-axis mask; but this ‘companion’ seemed relatively too bright. The attachment summarises most of my impressions.

In addition to what is shown there I can detail a Gamma Equ observation/session on Sept. 28 in very good and improving conditions. Keeping on it for over an hour (in spells!); initially sweeping it up in twilight. At first the impressions were as in the attachment. However as the seeing got better doubts with the companion increased. In the end I applied x665 (non-binoviewer) and still had a very good Airy with well defined rings. But no sign at all of star B! I was starting to wonder if I had strayed onto 6 Equ but no – anyhow its marked blueness would have been the giveaway.

One old trick, which I have tried before successfully (10” Newt.), is to slightly tilt the primary mirror to throw the rings away from where a faint companion might be. Not wanting to disturb the D-K’s collimation I removed the barrel from the 10mm Ortho (Zeiss) I was using; and with a bit of Blue Tack achieved the right tilt to get the same result – and absolutely no companion evident! I’ve not tried this eyepiece-method before so it awaits more clear nights to check it out.

I have seen some mention of the comes being variable and I note that Burnham’s Handbook gives it as a fainter magnitude of 11 as opposed to 8.7, which might indicate an M dwarf but if it is a flare star it must be one of very unlikely vigour!! I have spent hours on occasion with YZ CMi and got a measly, uncertain, 0.3 mag. ‘flare’! Kaler suggests G9 – K0 for Gamma Equ B. which seems to accord with my impressions of light orange at times.

Later in the night I applied the same technique to 85 Peg (0.52” 317º) and got a more definite glimpse (some uncertainty) of the companion than with all my efforts on Gamma Equ. But, as I say, more checking in prospect.

Regards,
David.

Attached Files



#63 Asbytec

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Posted 30 September 2013 - 12:09 PM

Excellent report, David. I'm itching to try this one. Your description of "over performing" success brings it home for me - fluctuating between "yes" and uncertainty. You're one time near certainty with a 6" mask is enough to motivate me to take on the challenge. Plus, the observation is one of those that fall into the realm of interesting.

#64 Astrodj

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Posted 30 September 2013 - 12:40 PM

I too have kept following this thread with interest. Last night was my first attempt at observing Gamma Equ.

My results were negative on AB, some details follow.

ZLM= 5.5
Transparency= 9 of 10
Seeing= 5, occasionally 6 of 10
10" f/4.7 Nwt, CO 25%
Equatorial platform
Magnifications= 182x, 300x, 364x, 600x
Eyepieces used= 6.6mm Cave Orthostar, 4mm Nihon Seiko Ortho, 2x 3 element Barlow

The 12.5 mag AC companion was easily seen. WDS shows a P.A. of 359. I estimated the P.A. of AC at 005 while at the scope and looked it up later. I used that as a reference for where to concentrate my search for AB. Diffraction rings were breaking up into points that shifted in and out from the primary. In occasional moments of better seeing the rings steadied enough to look like two diffraction rings, albeit briefly.

I had several impressions of a star point near the first diffraction ring that must ultimately be attributed to seeing artifacts as they were at a P.A. of between 25 and 45 degrees. Nothing was seen at the correct position angle that would suggest a 9th mag star.

I will try again, of course...

#65 Cotts

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Posted 30 September 2013 - 01:28 PM

Can't find it for two nights at Okie tex. 16" Zambuto f/5, 19% central obstruction.

Will keep trying.

Advice from a mod:
If you haven't seen it and you haven't tried, don't post.
If you haven't seen it but have tried, don't tell someone else they couldn't have seen it ( by hinting or direct comment)
If you have seen it, post your results dispassionately.

Dave

#66 David Gray

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Posted 30 September 2013 - 02:39 PM

Thanks Norme,

Actually I thought this one was going to be a walk in the park! If I did get the companion then I suspect it nearer mag. 10 than 9.

I was a little hasty with the graphic which I had started, and left, some weeks back and have amended a couple of things for correctness. :question:

Cheers,
David.

#67 fred1871

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Posted 30 September 2013 - 07:33 PM

David, a very useful report on your observing efforts on this difficult object. It's certainly more of a problem than most of us expected it to be!

Considering magnitudes again, if the secondary star is dimmer than mag 8.7 then the pair becomes more difficult; and the 19th - to early 20th century observers did usually assign a magnitude around 10 or 11 to it. Brighter than that starts with van den Bos in 1958, using the Yerkes 40-inch refractor. The pair was easier at that time than later, it had begun closing but was still reasonably wide - he got a measure of 1.94". Worley in 1988 (26-inch refractor) suggested a delta-m of only 3.3 (mags) - surprisingly bright. Hipparcos and Tycho put the delta-m at 4.25 and 4.0 respectively (1991 for both). Roberts in 2002 has delta-m 3.82, but that's in an R band (red light). If as Kaler suggests the companion is type G9-K0, the companion can be expected to be brighter in R than in V, and thereby reduce the delta-m as the primary is less red (type A9V).

Burnham's Handbook appears to have used the 19th century estimates of brightness for the secondary.

So it's still an open question of whether the secondary is variable; but if it were usually fainter than mag 8.7, we'd have an even more difficult double, so that doesn't help for telescopes of moderate size.

Your "messing around with ellipses" diagram is interesting - I'd suggest the larger ellipse, while possible, is unlikely; and Kaler's suggestion of ~250 year period would be similar to the smaller ellipse. You've plotted the 1994 measure, which shows how far out of trend it is (the briefly-reversing binary :grin:). The curve does suggest a pair continuing to close. Now if only we had a 2013 measure to confirm, or dis-confirm, that.

Your note about "eye estimates for the position" of the secondary also is a fit for an orbit continuing to close, and for a more rapid change and decrease in the PA; consistent with the diagram. So those observers with suitable telescopes should be checking for the possibility of a companion with noticeably smaller PA than previously, 220-250 as per your eye estimates; as well as very close, in the 0.6"-0.8" range. As the first diffraction ring with your 16.3-inch will be near 0.5", that's consistent with your drawing A.

So it's possible, but not certain, as you acknowledge, that you might have seen the secondary star.

Your observation in good conditions of 85 Pegasi is a useful check on what's possible. The delta-m for that pair is similar to Gamma Equ - 85 Peg has WDS mags of 5.83 and 8.9, so delta-m ~3.1, and the very good orbit for 85 Peg means there's no significant uncertainty in the separation you quote (0.52").

My final thought is that I envy you with a 16.3-inch DK with small secondary; seems to me it's a pretty much ideal planetary/double star telescope.

#68 azure1961p

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Posted 30 September 2013 - 08:27 PM

If you haven't seen it but have tried, don't tell someone else they couldn't have seen it ( by hinting or direct comment)

Dave


Well said.

Fred you might be interested to see the .17" double split Dave illustrated in another forum.

Pete

#69 fred1871

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Posted 30 September 2013 - 09:44 PM

Pete, yes, I did see that, showing a 0.17" pair as elongated, in the thread about "Detail on Ceres?" - an excellent result, and entirely believable given the telescope etc; consistent with Christopher Taylor's efforts, with RG Aitken's comments, etc. But I won't personally be attempting A 2145 with the (much) lesser telescopes I currently have. :grin:

Regarding telling other people - there's an implication involved, even if you're merely discussing the limits of physical optics, that someone could not have seen what they claim. An error has crept in. No dishonesty involved; incompetence isn't needed, we all sometimes get false positives. So if someone claims to see a double as a double at 0.5" with, say, a 63mm Zeiss Telementor (a very fine little telescope), the only response, whether or not you say it, is that it's beyond the bounds of possibility for that aperture.

That's because it goes beyond the physics, and no matter how keen the eye, it can't see what the optics can't show. As I've said before, that's quite different from differences in colour perception; and quite different from seeing fainter, where visual acuity can make a big difference.

In the case of Gamma Equ, we can say that the 1994 measure is anomalous, an "outlier" in Brian Mason's diplomatic language, plainly some kind of error is there; and David Gray's plotting of the measures shows that well enough. Is it a typo? - a copying mistake? - an error with the measuring system? - we can't tell, and the astronomer who made the 1994 measure is very competent and very experienced. But everyone has the occasional error, and later they might be able to identify how it happened.

Meanwhile, looking at what David Gray can see with his 'scope, I've got the same feeling Jonckheere had when using his first serious telescope for double stars - it was near 9-inch aperture, and he did not think it big enough - so his next telescope was a 14-inch, much more satisfactory. Sometimes the only way forward is more aperture, given optics of suitable quality and design.

#70 azure1961p

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Posted 30 September 2013 - 10:07 PM

There's interesting things in the errors that come through poor measures. Its a little frustrating on one hand but it adds a wild card element that can leave a lot in the lap of the observer. At anyrate I for one had no idea this double was this terribly difficult. Discovery is still alive here and that's a good thing.

Pete

#71 WRAK

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Posted 01 October 2013 - 02:44 AM

... one near-certainty with the 6” off-axis mask; but this ‘companion’ seemed relatively too bright...


David, do I understand it right that your other observations made this a false positive?

Regarding your observations with full aperture - impressive report. With an aperture of 415mm only seeing should be the limiting factor for resolving Gam Equ if the advertised data would be at least nearly correct - so may be seeing is the reason for the remaining uncertainities. It also shows that even evidently positive observations have to be double checked. From the specs of your DK scope would result a separation of about 0.6" - even with this small separation Gam Equ should be rather easy resolved with 415mm if +4.7/8.7mag are correct. I think you would come to the limit of your scope with 0.6" +4.7/~10mag.
But all this means that I will not only have to forget about my 140mm refractor but also my coming 200mm DK not to speak about the C925 with it's counter productive CO of nearly 0.4 - or I might have to put a mighty spell on it.

Remains quite interesting.
Wilfried

#72 Asbytec

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Posted 01 October 2013 - 07:30 AM

...do I understand it right that your other observations made this a false positive?

Or a positive maybe. :grin:

#73 David Gray

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Posted 01 October 2013 - 01:19 PM

... one near-certainty with the 6” off-axis mask; but this ‘companion’ seemed relatively too bright...


David, do I understand it right that your other observations made this a false positive?


As it stands I guess I would say that. But as far as the 6" off-ax. goes it is based on very few tries. I am modifying the mask for quicker attaching/removing as it is too tight a fit; supposed to 'drop' in the end and also needs a central knob or such.

I am only hoping my recent good seeing has not ended. They have just harvested and ploughed the adjacent wheat-field and I have suspected, over the years, that this seems to affect my local seeing for some weeks. Perhaps coincidence or simple supposition I don't know.

I will persevere regardless with Gamma Equ. I am hoping to check out similar doubles to further evaluate things. I will be trawling Sky Map of course but suggestions welcome - preferably those following the meridian as I have houses to the s'west and seeing is less reliable that direction.

This is an intriguing challenge and thank you all for your comments and insights on my report. Hopefully further offerings - inc. other doubles in due course!

Cheers,
David.

#74 WRAK

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Posted 01 October 2013 - 03:46 PM

Some suggestions:
ID Name RA Dec Separation Magnitude Magnitude2 Constellation
WDS02132+4030 MET14 02:13:13 +40:30:28 0,7 5,68 9,88 And
WDS04564-0510 HDS641 04:56:24 -05:10:17 0,6 5,49 9,64 Eri
WDS05397+2554 OCC231 05:39:44 +25:53:50 0,6 5,18 9,46 Tau
WDS06042-0643 HDS826 06:04:13 -06:42:32 0,6 5,24 9,45 Mon
WDS07123-4030 HDS1001 07:12:16 -40:29:56 0,7 5,31 9,4 Pup
WDS07187-2457 TOK42 07:18:42 -24:57:16 0,9 5,33 9,7 CMa
WDS08116+3227 CRJ2 08:11:39 +32:27:26 0,6 5,09 10 Cnc
WDS08319+5037 CRJ3 08:31:55 +50:37:00 0,9 5,96 10,07 Lyn
WDS08345-0044 MET53 08:34:32 -00:43:34 1 5,44 10,28 Hya
WDS13239+5456 PSF1 13:25:14 +54:59:17 1 4,01 8 UMa
WDS16278-0822 RST3949 16:27:48 -08:22:18 0,8 4,71 8,83 Oph
WDS17177+3717 HDS2446 17:17:40 +37:17:29 0,9 4,62 8,53 Her
WDS20176-1230 WZ15 20:17:39 -12:30:30 0,8 4,44 8,6 Cap
WDS23300+5833 STT496 23:30:02 +58:32:56 0,8 4,87 9,3 Cas
WDS23587-0333 BU730 23:58:40 -03:33:21 0,8 4,9 8,9 Psc
Wilfried

#75 David Gray

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Posted 02 October 2013 - 05:22 AM

Many thanks for these Wilfried – might get to look at some of them in a couple of days if the clear-sky forecasts hold……!

With regard to gamma Equ I have to say if I had included this in my occasional, more casual, double star forays then on the basis of my more-convinced ‘sightings’ I would have probably moved on to the next object quite satisfied as to the companion detected ! The need for more experience my tackling this type of double seems indicated…..

You may right with Bill's observation and I hope he continues to tackle gamma - I've not laid the matter to rest that's pretty sure!

David.






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