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#1 Asbytec

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Posted 28 October 2013 - 10:16 PM

Rainy season is grudgingly slow to give way to clear skies. Observing lists grow with impatient drive to succeed. Instead, I spent more time failing on what seemed like a great night.

At first I was curious about Delta Cyg (PA 218, Sep 2.71, primary 2.89, companion 6.27, delta M 3.38), so that was the first target of the night. I found it quite easy at 162x and very easy at 243x. Sketch below. Quite nice double. At lower power, the rings did seem to skirt the companion, but at higher power that was not a problem.

I also tried 1 Del (P.A. 350 SEP 0.9 MAG 6.2-8.02) and 13 Del (P.A. 199 SEP 1.5 MAG 5.64-8.24), but was interrupted by an hour of cloud cover and, later, the neighbors roof. These were very difficult. I felt 13 Del was slightly easier and was able to guess the PA. The companion appeared more like a consistent knot than a distinct disc. The rings were rolling a bit, but it seemed to hold steady due south of the primary. Whereas the rings would roll, flare, and knot up a bit around the primary, due south the knot seemed more of a fairly consistent blob of light than a rolling, flaring ring. I cannot say I observed 1 Del companion at all. I followed 1 Delphi right into my neighbors 2 story roof without success.

But, those were just warm ups. First up in Perseus was STF 268 (P.A. 131 SEP 2.7 MAG 6.72-8.5.) This one is easy at 162x and very easy at 320x as shown in the sketch below. I felt the companion had a tiny bit of reddish hue to it, the primary maybe a tiny bit of yellow, or at least off white.

BU 9AB (P.A. 210 SEP 1 MAG 6.42-8.64) was a bit more difficult, but I finally glimpsed a very faint speck about PA 200. This was curious because I failed to spot it on an earlier attempt and ruled it to be too difficult. It certainly is difficult, but not impossible. It's tiny speck of a companion offered a few of those very comfortable "yes" moments.

It's also curious because I had the opposite result with STT 69 ( P.A. 325 SEP 1.5 MAG 6.6-9.13). I had reported it as moderately difficult earlier, but the companion was not visible tonight. So, one did not show then did show, the other showed then did not. Both are pretty tough, one showed and the other did not.

HU 544 (P.A. 102 SEP 1.6 MAG 6.72-8.2) proved a bit easier and was a welcome relief to the grueling observation of BU 9AB and STT 69.

Two remaining very difficult ones closed out the Perseus session: STT 71AB (P.A. 230 SEP 0.8 MAG 6.86-8.66) and 34 Per (P.A. 146 SEP 0.6 MAG 4.72-7.34). Both of these are sub arc second splits, and the only one I felt comfortable enough to include in the sketch and a quite possibly maybe is STT 71AB. There was a little something going on near PA 230, like a small faint point or hump. I had to rule 34 Per as a failure. It's companion was probably too tight and too dim.

Okay, so onto the Dog Star and the Pup (P.A. 83.2 SEP 9.8 MAG -1.46-8.5). Seeing was strange tonight, it seemed to roll between 6 with some dispersion and 8/10 almost regularly like a huge series of waves overhead. But, there were times I could clearly see Sirius' Airy disc and about 7 or 8 well defined rings. (How many folks have seen Sirius this well? Normally it's a blurry mess.) At other times, it was a blurry mess for a few seconds before calming down again. On this one, well, I had a couple of "yes" moments at best. Not the warm kind you feel comfortable calling, though, so I cannot say I saw the Puppy star. I suspected one of those yes moments was an internal reflection right about where the Pup would be, but it became apparent only near the edge of the field. A couple other "yes" moments were rules spurious effects. So, a couple of "yes" moments but no Pup.

I also took a gander at AR Cas (cluster?) and Jove. But, that's a sketch for another thread.

Seeing was fair over the rooftops looking at Delphinus. Seeing seemed good in Perseus, at first, then the discs began to jump around a bit. Looks like about 7/10 for most of the night with alternating periods of 8/10. NELM was about 4 to 4.3, I think TLM in the vicinity of Cassiopeia (which just does skirt the worst of the light dome) was about mag 11.

Anyway, I hate to fail and wish I could have gotten 1 Del, 34 Per, and STT 69. I also did not resolve Atik (P.A. 23 SEP 1 MAG 3.91-6.7) but it does seem doable.

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#2 Asbytec

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Posted 28 October 2013 - 10:29 PM

Delta Cyg.

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#3 Astrodj

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Posted 28 October 2013 - 11:09 PM

Very enjoyable report, Norme. Thanks! Between you and Pete, I have a BIG list of prospects to go through when the time is right. Should be a blast.

#4 azure1961p

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Posted 29 October 2013 - 07:41 AM

Hi Norme,

I had 1 Del slated on my fall list but passed on them due to the seeing though I regret now I didn't try it. the last time out . I'm adding 13 Del to the list .

Glad you had success (again) with Delta Cygni. I like it in that it is challenging but not prohibitively rare in allowing for a good resolve. Mediocre seeing will even cough up the secondary with care I find but nothing beats a great night of seeing to make it stunning. Again a fine drawing btw.

Perseus is jjuusstt starting to clear my roof so Im penciling in these doubles for Early Winter. STF268 sounds like a fine sight though and I look forward to it though early winter starts throwing up those Pickering 4 nights making 2.7" seem like .7". Ahh.

BU9AB I added to my SS list last night when I first read through your listing. Sounds like the kind of challenge I could enjoy. I'm adding STT69 here as as a comparison double for sky difficulty.

I've NEVER had winter seeing favor the pup - not that is doesn't occur but for one reason or another not the times Ive looked. Its always a brilliant boiling mess that flickers in my field like an arc welders flashings. Beautiful but no pup just yet.

I'm interested in 1 Delphini particularly as Ive come to see just how difficult even modest delta mags can be at 0.9". I've found a pitfall in observing is Ive got the expectations of what 0.9" should be based on nearly 20 years with the 8" and more than once I catch myself looking in the wrong place. I never have this issue with the 70mm as its a different look altogether but the 6 is just close enough to the 8 that I find I confuse the two from time to time.

A great night out it looks like Norme has SS proven a help here ?

Pete .

#5 Asbytec

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Posted 29 October 2013 - 07:53 AM

Pete, Id be interested to know if you could do 1 and 13 Del. Would also like to know how your 6 or 8" will do on STT 69 and BU 9. Both are very challenging and are worth another look.

Yea, SS seems to be a great star hopping tool and a place to hold a preplanned observing list. Love it.

Thanks, DJ, hope you can get out soon enough. The tropical Storms just keep passing too close, for now.

#6 fred1871

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Posted 30 October 2013 - 01:23 AM

1 Del - sounds familiar, I thought, so I looked through my observing list notes, and sure enough I'd had a look at it back in 2008. That was just before I got the 140mm refractor, so I was using the C9.25 on the night, and I've recorded the seeing as "good".

The companion was seen at 290x as a small speck touching the primary; at 470x it was just separated. Not an easy pair, no doubt not helped by the large CO of that telescope.

I've somehow overlooked observing 13 Del in the past. I'll try it before Delphinus starts getting too low in the west. At the moment I'm hopeful of a clear night (maybe steady too?) coming up tonight.

#7 Asbytec

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Posted 30 October 2013 - 01:37 AM

Fred, thanks. 1 Del is that tough, it seems. I'd think your 140 would do well on 13 Del. Would love to know how well the companion is seen.

#8 fred1871

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Posted 30 October 2013 - 01:58 AM

Another "find" in my observing notes. BU 9 in Perseus this time. It's a C8 observation again, from the end of 1995, when I was in California, so BU 9 was at good altitude. Seeing was fairly good on the night. At 225x it was double, a very tight pair, "the secondary nestled beside the primary".

This sounds a little easier than I'd expected, so I looked up some more data. BU 9 has been gradually getting closer over time. The Hipparcos measure, 1991, was 1.3", down from the 1.5" of discovery in 1872. With 1.0" listed for 2009 that would suggest the closing rate is quicker in recent times, assuming the 2009 and 1991 measures are of high accuracy. Taking them as given, that would suggest BU 9 was a little wider - therefore easier - in 1995 when I observed it. A linear interpolation of the figures might suggest 1.2" at that time. That would account for it not being more difficult.

I'll try it again soon. Despite low altitude (20 degrees), the seeing can occasionally be fairly good.

#9 Asbytec

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Posted 30 October 2013 - 05:32 AM

Okay, I'm curious about the sep on this one. It does seem to be placed a bit far from where it should be.

The rings were not entirely steady and the speck was fleeting, so it's a bit difficult to say (eyeballing it) where it could be. It maybe be closer than 1.0" arc, and maybe the reason it is so difficult. I noted a spot - what looked to be - outside or maybe even on the first ring. So, I am not really sure how or why it would appear to be there.

When you say, "nestled beside the primary" do you mean as a function of relatively low power or inside the first ring (of an 8") kind of nestling? That would put it well within the first ring for a 6" (wagging it) years ago. I don't think it's that tight. Give it a try, too, it'd be interesting to know where this one actually is.

In any case, having failed then being sure it was spotted simply cries for confirmation...soon as the tropical storm passes, hopefully, passing overhead tomorrow.

Edit: You know, if it closed slowly from 1.5" arc in 1872 to 1.3" arc in 1991 (just 0.2" arc in a century assuming some accuracy) then rapidly from 1.3" arc through 1.2" arc in 1995 to 1.0" arc in 2009 (another 0.3" arc in just under two decades 1991 to 2009), maybe it passed perigee and is widening? If your estimation is close, then it closed 0.2" arc in 14 years (1.2" to 1.0" arc) from 1995 to 2009. It might have gained ~0.1" arc in the 4 years since 2009. If 2009 is correct at 1.0" arc, it could well be closer to 1.1" arc today depending on when it hit Perigee. Neat to contemplate that, it's speed does suggest perigee is sometime either before or after 2009, a period it was moving rapidly relative to 1872 through 1991.

#10 fred1871

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Posted 02 November 2013 - 02:09 AM

Norme, the primary star for BU 9 is pretty bright in a C8, so there's scattered light as well as a first diffraction ring. That ring for the C8 would be closer to the primary than the secondary star - the ring centre near 0.9", the secondary star slightly wider.

Looking at your added comments: this is not a super-quick binary, the total change in PA from 1875 to 2009 (134 years) is only around 50 degrees.

I had a look at the measures in various sources on hand; not the complete list. The early measures by various observers were recorded by Burnham in his 1900 catalog - PA pretty consistent, some scatter in separation, his conclusion that there was no real evidence of change.

The two 1950s measures I found suggest the PA had been moving - 1954 gave 183, 1959 gave 188 - one shouldn't assume 5 degrees in 5 years because the accuracy is likely not quite that good. But it does tell us the angle had shifted by about 25 degrees in 80 years since discovery. I'm sure there was some shift in the first twenty years, covered by the measures Burnham listed, but it's likely small and therefore doesn't show in the small scatter of measures.

Angular change has been quicker since the 1950s: ~27 degrees in 55 years.

Separation - there's a suggestion it might have widened somewhat before the recent decrease.The 1950s measures average at 1.65". And 1991 - Hipparcos/Tycho - is definitely closer than that, near 1.3". A 2005 measure gave 1.0", the same as 2009.

So at this stage I'd not think BU 9 has passed through periastron (not 'perigee' - that's to do with Earth orbits). It's not a really nearby system, at ~153 ly; and the orbit will be centuries long; so at present I think we might be seeing it moving into periastron. How long will it be there? - and how close will it get? - and when will it start widening? - we'll have to wait and see.

#11 fred1871

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Posted 02 November 2013 - 08:38 AM

Norme, I had a clear and steady night, and had a look at both 1 Delphini and 13 Del. Both with the 140mm refractor. I described earlier in this thread seeing 1 Del with C9.25; I can now report that the refractor also makes it possible.

1 Del has a separation that puts it into the Rayleigh gap for 140mm - the first dark interspace between primary disc and first bright ring. With a delta-m of 1.8 (mags) I expected it would be possible because I've managed some pairs about this separation with somewhat larger delta-m.

1 Del was visibly double at 250x though not as cleanly imaged as some pairs at this separation. The secondary star was more like an extension, less bright, of the primary. 400x gave a better view, showing the pair as a pinched (notched) unevenly bright rod. Not the look of image I'd expected, but it was definite in form.

Unsurprisingly, 13 Del was not easy with 140mm. I caught glimpses of the companion at 250x; at 400x it was definite. It was a tiny speck, slightly smudged, just outside (edging) the first diffaction ring. I then went back to 250x, finding the companion slightly easier after the 400x view. It was not a brightening of the diffraction ring but adjacent to it, and diffraction ring motions did not tend to suggest star images on the night. PA was a good match for the 1991 figure of 199. This one has changed little since discovery by Burnham in 1871 (BU 65).

Both of these are challenging objects for 140mm. Unless air steadiness is pretty good they'd not be possible. In the case of 1 Del the benefit of the 235mm SCT was extra aperture despite large CO; making possible separation with enough power. For 13 Del, I'll try it again with 235mm, as I've only observed it with the refractor so far.

#12 azure1961p

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Posted 02 November 2013 - 11:11 AM

Fred - nice report. It looks like I might be able to make a go of both with my 8" this weekend. I want to add Bu9 to this as well as some of the others that have been floated here recently. Sounds like you have a fine refractor too.

Pete

#13 WRAK

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Posted 02 November 2013 - 11:44 AM

Fred, 1 Del with 140mm is very close to a limit observation I think. It seems that this time you had this curious distinct pointed elongation resp. rod experience I had so far twice with other unequal doubles.
WDS notes for 13 Del include a "variable" remark without explanation - may be this is a reason for it being more difficult than the numbers indicate.
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#14 Asbytec

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Posted 02 November 2013 - 12:23 PM

Fred, outstanding. So, 1 Del, then, would be a Raleigh split for your 140 putting it between 0.9" and 1" arc very near the first minimum. You describe it more of a unevenly bright rod, a great description of some very close pairs I've seen with delta M near 1. Interesting. Would that place it closer to 0.9" arc, then? Or closer?

For my 150, then, it would be a bit closer to my brighter first ring. With a delta Mag close to 2, it's becoming difficult. I'm confident it's difficult but possible, just need a calm night to bear that out. I suspect something near delta M ~2 is approaching a level of difficulty. Gotta try that one again, if given a chance. It's interesting to know how deltaM affects close pairs inside the first ring.

It's interesting 13 Del was difficult, but it's closer to your first ring than mine. It was difficult for me, too, if not inconclusive (per my "resolved?" thread.) I should have gone to 380x for a look, but stayed at 320x. I'd bet your rings were more steady than my observation, so yea, it makes sense with some seeing these would be more difficult. I've done similar separations (BU 1238 below) in better seeing and detected a speck, but this one was involved in the ring. Maybe it should not have been that difficult at about 1.5" arc, but it was.

Yea, both are difficult and one reason I chose to go after them. I'm glad you took the time to observe them, it's always nice to share an observation with others. You succeeded on both, I might have gotten the latter. Well done, thank you for sharing your observation.

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#15 Asbytec

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Posted 02 November 2013 - 01:33 PM

Sure, BU 9 may not have passed periastron (thank you for the correction), but it's interesting to suspect it's at least close as might be suggested by it's rate of change in separation and PA.

It's interesting it appeared to widen from 1.5" (first) to 1.65" then tightened to 1" arc (last.) Wish I could do orbital mechanics in my head.

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#16 fred1871

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Posted 08 November 2013 - 01:43 AM

Norme, I've now obtained the complete set of measures for BU 9. There's a fair amount of scatter in the earlier years, and the occasional outlier on separation (especially) and sometimes on angle, later. The Hipparcos/Tycho measures and the more recent ones, by speckle interferometry, look good.

I've done a preliminary set of means for different dates, from discovery until 2009 (last data at present).
I dropped the angle for 1872 (discovery) out of the mix because it's inconsistent with those from 1875-1885.

Here are the numbers, set against typical dates for each figure - each separation and angle is typically a weighted mean for a date that fits within a close range of dates. There are 59 measures listed which I've reduced to 11 integrated sets of figures.

1875 1.55" 160d
1900 1.75" 163
1916 1.8" 171
1922 1.8" 172
1935 1.6" 176
1955 1.6" 183
1965 1.5" 186
1975 1.5" 191
1991 1.25" 201 av of Hipp and Tycho
2005 1.05" 207 speckle
2009 1.0" 210 speckle
[separations to nearest 0.05"]

A different choice among the preferred measures could give a slightly different pattern, but not radically different.
This table will give some differences to the orbital pattern from the one you drew, based on my earlier (insufficient) data set. Once again, I find that having a long series of measures changes the look of the orbit. I'll be writing up some other examples soon.

Meanwhile, for BU 9, it looks as if the binary reached a maximum - whether a primary or a secondary maximum, and that probably won't be clear until we see the pattern following the periastron that it's now heading for. That maximum was in the first quarter of the 20th century. For the near future, BU 9 will continue to close, and the rate of change of angle has speeded up over time - if we take 1875-1955, 23 degrees in 80 years (just under 0.3 deg/per year) compared to 1955-2009, 27 degrees in 54 years (0.5 deg/per year).

In coming years we'll see how close the pair get, how quickly the angle changes, and when it begins widening. All fairly much guesswork at the moment. The orbital period will be centuries long. My impression is that this one is not ready yet for a first attempt at calculating its orbit ....

#17 Asbytec

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Posted 08 November 2013 - 02:57 AM

Fred, that's amazing work. It moved 0.05" arc in 4 years from 2005 to 2009 (1.05" arc to 1.0" arc.) If we can assume pretty much the same motion since 2009, then in 2013 it would be about 0.95" arc sep (of course given any error and judging form the best info we have - that you dug up.) That's just outside the first minimum, if I calculate it correctly at about 0.83" arc.

Visually, then, it's pretty close to ~0.27" arc - possibly just grazing - inside the inside the first ring (at 1.22" arc +/-, maybe ~1.0" to 1.5" arc in breadth? The second ring is centered ~2.1" arc and pretty easily seen from the first offering as much or more than .6" arc clearance.) So, first min is ~0.83" arc, add 0.12" arc to get to 0.95" arc companion position. Another 0.27" arc to get to the center of the first ring minus the breadth of that ring (whatever it is)...it might appear visually right on the ring if the rings are somewhat unsteady? Hmmm...thinking out loud.

At delta M ~2.2, there is no wonder it's so difficult if not, indeed, impossible being that dim at or just inside the first ring. It's on my redo list for confirmation - as is STT 69, which should be also closing but a bit further out and slightly dimmer at deltaM ~2.5.

Yes, it does appear to be changing separation rapidly of late. Factoring in PA is kind of hard to do mentally. Maybe a more accurate plot of your data points is in order. Do you know what program David Gray was using? Maybe I should ask. I have to do it manually.

#18 fred1871

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Posted 08 November 2013 - 07:13 AM

Norme, brief note - I asked David Gray and he said he uses Corel Draw. It's a pretty comprehensive program, and he obviously uses it very well. Only drawback that I can see is the price.

I'll attempt further comments on BU 9 orbit later. For now, I'll provide the multi-decimal measures from 2005 and 2009 - for 2005, 1.048" at 207.1d; for 2009, 1.006" at 209.6d. There was a 2008 measure which I didn't list, neatly between - 1.034" at 209.2. These numbers for separation will not be exact to 3 decimal places as given, but might be considered as plus or minus 0.01" as an estimate of possible accuracy. Even with speckle and adaptive optics, there will be error bars, but smaller than in the past.

#19 Asbytec

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Posted 11 November 2013 - 05:45 AM

I managed to confirm STT 69, but not BU 9 on an average night.

Edit: A couple more attempts at BU 9, though, and I have some assurance the companion is visible. Yes, so are seeing effects, but I do just get a glimpse of a speck at the right PA a couple or a few times...sometimes. It's just enough to begin to suspect it's there, but not close to being absolutely unmistakable. This one is certainly difficult, but it seems there is just enough there to say with reasonable certainty it's not impossible. Extremely difficult, but probably not impossible. Tough one...very tough.

If one were scanning the skies for doubles in a 150mm obstructed scope, we'd likely give this one a pass and move on to the next. If one were determined, already knowing it's a double, then it's possible to glimpse it with patients and study, IMO. Even the sketch below is too generous because it's a snap shot of the best moment where the companion might have been seen, most of the time it was not there.

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