Return to the Cloudy Nights Telescope Reviews home page


Observing >> Double Star Observing

Pages: 1 | 2 | 3 | 4 | (show all)
Bill Boublitz
super member


Reged: 05/04/13

Re: Ever observed COU1900? new [Re: WRAK]
      #5843789 - 05/06/13 03:11 PM

Thank you! (WRAK)

Post Extras: Print Post   Remind Me!   Notify Moderator  
R Botero
Pooh-Bah


Reged: 01/02/09

Loc: Kent, England
Re: Ever observed COU1900? new [Re: 7331Peg]
      #5844170 - 05/06/13 06:34 PM

Thanks for your report John. Your experience seems similar to mine. Did you notice any colour in the secondary of BU1074?
Roberto


Post Extras: Print Post   Remind Me!   Notify Moderator  
7331Peg
Sirius Observer
*****

Reged: 09/01/08

Loc: North coast of Oregon
Re: Ever observed COU1900? new [Re: R Botero]
      #5844383 - 05/06/13 08:28 PM

No, I didn't see any color in Bu 1074's secondary, Roberto, probably because I only saw it with averted vision. I'll try again on a night of better seeing.


John


Post Extras: Print Post   Remind Me!   Notify Moderator  
WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Ever observed COU1900? new [Re: 7331Peg]
      #5845408 - 05/07/13 12:08 PM

So at least the resolution of BU1074 with a 6" refractor seems to be confirmed as rather a limit observation - not bad for a 2.5" +7.2/11.2mag double.
Wilfried


Post Extras: Print Post   Remind Me!   Notify Moderator  
WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Ever observed COU1900? new [Re: WRAK]
      #5861442 - 05/15/13 03:30 AM

Had yesterday a clear night - seems rather rare lately for my location. Seeing was not this good - around Pickering 5. NEML about +3.45mag.
Had despite this a look at COU1900 with a 235mm SCT - the distorted and dancing diffraction pattern did not allow a resolution.
Tried then with the 140mm refractor. The image was better due to less influence of the bad seeing but the diffraction pattern was still distorted and I had the curious experience of a spurious disk slowly changing position within this pattern - had never before this experience. No resolution of any companion although this should be possible with 140mm aperture and the given values for separation and delta_m. But seeing was too bad to take this as evidence that these values are wrong. Have to try again - looks rather good for tonight as the sky is without any clouds now. Have also to try BU1074 myself next time.
The companion of COU1900 seems certainly a bit elusive as Roberto also reported a non split in a private email communication.
Will this get a full turn around again to a suspected "non exist"?
If COU1900 near Mu UMa is in your field of view and you have a scope up from 130mm aperture - please try this one if you have also reasonable fair seeing.
Wilfried


Post Extras: Print Post   Remind Me!   Notify Moderator  
7331Peg
Sirius Observer
*****

Reged: 09/01/08

Loc: North coast of Oregon
Re: Ever observed COU1900? new [Re: WRAK]
      #5863586 - 05/16/13 12:26 AM

I took another run at this last week with a C9.25 and I "think" I picked out the secondary with direct vision, but I really need to see it a second time before I'm confident it was there. The seeing hasn't been at all cooperative, and the weather looks like it's not going to cooperate either for the next week.

I did confirm Bu 1074 in the SCT with direct vision that night.


John


Post Extras: Print Post   Remind Me!   Notify Moderator  
WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Ever observed COU1900? new [Re: 7331Peg]
      #5863719 - 05/16/13 02:54 AM

John, this gets quite interesting now - resolution of BU1074 but not COU1900 in the same session strongly indicates that the advertised magnitude of COU1900 has to be wrong if we still consider COU1900 not as bogus.
Last night I tried myself again with my 140mm refractor with NEML +3mag and Pickering ~6. Could not resolve COU1900 but this could be the effect of the not this good seeing. Could also not resolve BU1074 but for this I would anyway need perfect seeing to resolve this with 140mm.
Have to get more familiar with my C925 to try this with confidence.
Wilfried


Post Extras: Print Post   Remind Me!   Notify Moderator  
R Botero
Pooh-Bah


Reged: 01/02/09

Loc: Kent, England
Re: Ever observed COU1900? new [Re: 7331Peg]
      #5863934 - 05/16/13 08:59 AM

I had a similar experience. I seem to have been able to resolve BU1074 much more "easily" than COU1900 of which I am not sure about. John, did you manage to see any colour in the companions of either?

Roberto


Post Extras: Print Post   Remind Me!   Notify Moderator  
7331Peg
Sirius Observer
*****

Reged: 09/01/08

Loc: North coast of Oregon
Re: Ever observed COU1900? new [Re: R Botero]
      #5864759 - 05/16/13 02:49 PM

No, no color seen in the secondary of either Bu 1074 or Cou 1900. For that I'll need more stable seeing than I've had.

I've noticed the colors of the primaries in the two stars are a big factor here. That of Bu 1074 leans toward orange (K2), while that of Cou 1900 is bright white (A2), plus it's 1.2 magnitudes brighter (6.0) than Bu 1074 (7.2). At any rate, that white glow is much harder to see past than the softer glow of Bu 1074.

So I have a feeling that's a big part of the reason we're having more difficulty with Cou 1900. That would also make the secondary seem fainter than it is, at least in comparison to our experiences with Bu 1074. Of course it's still possible that the secondary of Cou 1900 actually is 11.0 instead of the 10.0 listed for it, which all but puts it out of reach.

Wilfried, I'm using a two-speed external focuser on my C9.25. Without it, I don't think I could see the secondary of either of these stars unless I just happened to get lucky. I found the focus had to absolutely precise to see either of the secondaries -- just a slight turn of the fine focus knob in either direction and I would lose them.


John


Post Extras: Print Post   Remind Me!   Notify Moderator  
WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Ever observed COU1900? [Re: 7331Peg]
      #5864822 - 05/16/13 03:19 PM

Quote:

...Wilfried, I'm using a two-speed external focuser on my C9.25. Without it, I don't think I could see the secondary of either of these stars ...



John, I share this opinion - the idea to change focus by moving the primary (or in some cases the secondary) mirror seems rather strange to me. In best case (means without any noticeable focus shift) this could give the performance of a single speed focuser certainly not of good use for double star resolving.
Concerning colors: My eyes must be rather bad in this regard. Only in a few very evident cases I can name colors especially yellow and orange - thats it. Most stars seem to be only creamy white to me. But this is may be also a result of my current focus on limit aperture for resolving unequal doubles.
Wilfried


Post Extras: Print Post   Remind Me!   Notify Moderator  
WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Ever observed COU1900? new [Re: WRAK]
      #5890173 - 05/29/13 03:05 AM

Last night to my surprise a clear sky, rather dark for my location with NEML +3.5mag. Seeing depending on scope rather stable with Pickering 5-7 but high humidity gave brighter stars a halo and fainter stars got fuzzy blobs with higher magnification - so not this good conditions for splitting unequal binaries. Tried first with the C925 after checking collimation with Duncam mask - got a hint for a slight miscollimation but the rods did some dancing of their own so this was not conclusive. A Donut mask produced a quite concentric diffraction pattern so I did not change anything.
COU1900 was rather fuzzy at x335 (and even more at 470) and I could not see any companion. Then I tried BU1074 and had the impression of a brighter primary despite +7.2mag should be noticeable fainter than +6mag. But again no resolution here - only when moving the object with slow motion controls over the field of view (this sometimes helps me resolving tight doubles) I got a hint of a companion at 4:30 o'clock in alt/az-mode meaning translated into degrees about 120. But I think this was rather an effect of the mentioned slight miscollimation and anyway in the wrong position as I checked afterwards.
Tried then with the 140mm refractor with quite an improvement in image quality due to the smaller aperture but both COU1900 and BU1074 were at x280 already quite fuzzy with no chance for detecting a faint companion.
Wilfried


Post Extras: Print Post   Remind Me!   Notify Moderator  
fred1871
professor emeritus


Reged: 03/22/09

Loc: Australia
Re: Ever observed COU1900? new [Re: WRAK]
      #5891407 - 05/29/13 09:43 PM

Wilfried, your experience with these pairs is a reminder that good seeing conditions, as well as dark sky, are needed for doubles - indeed, steady air and no bloating of star images matter more than sky darkness.

I expect both these doubles, COU 1900 and BU 1074 need good conditions to be seen. COU 1900 may turn out to be the more difficult if the photometry is misleading, and the companion a lot dimmer than the current listing.

As I've mentioned, these doubles are always low in my sky so I won't get an atmosphere that allows me to see them as doubles. Higher in the sky, I've observed a few pairs similar to BU 1074, and was able to see the secondary star in each case with my 140mm refractor. But it does always depend on the atmosphere allowing that to happen: these are not easy doubles for 140mm.

235mm should be better, if collimated, thermally stable, and the atmosphere is good - but my recent observing, including various doubles looked at with both 140mm and 235mm, does not always show a benefit to the larger aperture. With pairs like this it's near-equal. With very close bright doubles, fairly close dim doubles, and not-too-close pairs with very dim secondary stars, the 235mm pulls ahead. Aperture wins, but only for some doubles, and under good conditions.

I'll write up the details of the comparisons fairly soon, when I've done some more observing of the same pairs with both telescopes.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Nucleophile
super member


Reged: 05/24/13

Loc: United States
Re: Ever observed COU1900? new [Re: WRAK]
      #5908526 - 06/07/13 06:33 PM

I traveled to an alternate viewing spot a few days ago with my gear to get this one.
Observed with a f/5.9 8 inch reflector on a night of good seeing (Pickering 7) I recorded the following:

340x(3.5mm Pentax XW): transiently observed as resolved to two objects;
390x(3.5mm Pentax XW + Paracorr type1): right at the border of resolved and split; the Paracorr sharpened the image just enough to allow this vs viewing with the Pentax alone
400x(3mm Radian): split suspected a few times but cannot definitively state as such.

This object was fairly tough in this instrument on this night ( I blame my troubles on the swarming mosquitos )


Post Extras: Print Post   Remind Me!   Notify Moderator  
Nucleophile
super member


Reged: 05/24/13

Loc: United States
Re: Ever observed COU1900? new [Re: Nucleophile]
      #5908542 - 06/07/13 06:42 PM

Should have mentioned in the last post the NELM for this observing site is ~5.7.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Nucleophile
super member


Reged: 05/24/13

Loc: United States
Re: Ever observed COU1900? new [Re: Nucleophile]
      #5908547 - 06/07/13 06:46 PM

I have been able to use my 15" reflector to get pictures of doubles with this mag difference/separation before with my Nikon on a steady night when I can get longer exposures---this should help to tell us if the companion is a phantom. For that matter, it should be a breeze with my 15" reflector---to bad it is in a bad place requiring travel--but now I have my excuse!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Bill Boublitz
super member


Reged: 05/04/13

Re: Ever observed COU1900? new [Re: Nucleophile]
      #5908984 - 06/07/13 11:25 PM

Very happy to read your post, Mark. I have remained hopeful something could be gleaned for this neglected double, but reports suggest changes in the system or perhaps inaccuracies in the ephemera. NELM 5.7 should be more than adequate for this pair. Your report is inspiring. Thank you for taking the time to go out there and look!

Post Extras: Print Post   Remind Me!   Notify Moderator  
WRAK
scholastic sledgehammer


Reged: 02/18/12

Re: Ever observed COU1900? new [Re: Bill Boublitz]
      #5909528 - 06/08/13 10:43 AM

Mark, interesting report. Pickering 7 and NELM +5.7mag should be sufficient to resolve COU1900 with a 6" refractor with the given parameters with ease so it should be even easier with an aperture of 8" even if a reflector. The first diffraction ring with 8" should be in a distance of 1" so there should be enough room for the 2.4" separated companion to be seen. It should be fainter as the first ring but much brighter than the second ring and sit somewhat outside the 3rd ring so there is no competition with the diffraction pattern even with a slight jumping in the seeing according to Pickering 7.
May be the fast f/5.9 is a topic here and not even a coma corrector is of much help?
Mark - if you ever have this opportunity again please have also a look at nearby BU1074. If you can resolve this one (same separation but primary and secondary +1.2mag fainter) but not COU1900 than this would be more or less proof of an error in the advertised WDS data.
Wilfried


Post Extras: Print Post   Remind Me!   Notify Moderator  
Nucleophile
super member


Reged: 05/24/13

Loc: United States
Re: Ever observed COU1900? new [Re: WRAK]
      #5910196 - 06/08/13 06:11 PM

I will be certain to observe Bu1074 when I re-examine COU1900.

Ideally, I would like to also image both of these as part of the data collection.
Hopefully next weekend (or sooner).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Nucleophile
super member


Reged: 05/24/13

Loc: United States
Re: Ever observed COU1900? new [Re: Nucleophile]
      #5916919 - 06/12/13 12:52 PM

Quote:

I traveled to an alternate viewing spot a few days ago with my gear to get this one.
Observed with a f/5.9 8 inch reflector on a night of good seeing (Pickering 7) I recorded the following:

340x(3.5mm Pentax XW): transiently observed as resolved to two objects;
390x(3.5mm Pentax XW + Paracorr type1): right at the border of resolved and split; the Paracorr sharpened the image just enough to allow this vs viewing with the Pentax alone
400x(3mm Radian): split suspected a few times but cannot definitively state as such.

This object was fairly tough in this instrument on this night ( I blame my troubles on the swarming mosquitos )




It seems I have to retract this observation. Not only can I not duplicate this observation (albeit from my home site), but I now know that this instrument produces an artifact at high magnification in the vicinity of the position angle where the secondary is said to be found. I had not been using this instrument for these type of studies until recently.

I apologize for this.

I had the same issue with 26 Draconis, which also has a position angle around 300-310 degrees.

The good news is that this artifact likely did not compromise my views of the companions of 42 Ori and Gamma Equ--two binaries I reported on previously whose results have been sent to Sissy Haas. Of course, I will be keen to observe them again in the coming months. Fortunately, the result for COU 1900 was not yet presented to Sissy.

Here is the interesting part: I attempted several careful observations of both COU 1900 and Bu 1074 with my 15" reflector and can definitively state I do not see what is purported by the latest data--clearly something has changed and/or there are errors.

I will be presenting this later information along with positive observations (and an image) of a very similar system (STT 344 in HER) in a separate post within a few days.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Bill Boublitz
super member


Reged: 05/04/13

Re: Ever observed COU1900? new [Re: Nucleophile]
      #5917233 - 06/12/13 03:41 PM

Thanks for staying on this, Mark. I had remained hopeful though pessimistic. If the data were accurate, this object would be little challenge for a 4" instrument. You might forward your negative to Sissy. We should remove it from the list. Perhaps someone could suggest another to take it's place in the table? Wilfried.... is that you?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | (show all)


Extra information
0 registered and 4 anonymous users are browsing this forum.

Moderator:  PJ Anway, Rich (RLTYS), rflinn68 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 4432

Jump to

CN Forums Home




Cloudy Nights Sponsor: Astronomics