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ggalilei
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Another other double-double new
      #5969928 - 07/14/13 02:53 AM

I'm sure everybody here is familiar with nu Scorpii, but just in case someone (like me till yesterday!) has not tried it yet: this is a pretty double-double, and a bit of a challenge for smaller apertures. I just split it tonight with a TSA 102. The B components are 6.6 and 7.2 at 2.4", an easy split at 100x or less; but I had to go to 270x for a convincing split of the A components: 4.2 and 5.3 at 1.2". If you haven't tried them yet, it's worth a look.

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GlennLeDrew
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Re: Another other double-double new [Re: ggalilei]
      #5969950 - 07/14/13 03:37 AM

An interesting aspect of nu Sco is that it's a member of the Sco OB2 association, and is the illuminating source of the huge reflection nebula, IC 4592.

Not too far north lies xi Sco, which is an easy double-double in smaller scopes. And the Struve 2470/2474 pairs in Lyra make an even easier--and almost spookily symmetrical--double-double for small scopes.


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ziridava
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Reged: 08/17/12

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Re: Another other double-double new [Re: GlennLeDrew]
      #5970094 - 07/14/13 09:05 AM

Antonino
You are right,Nu Sco is a beautiful double-double star.
I was successful at splitting this more times with my 125mm F/7 Newtonian.
I just would like to add Nu Sco as being a binocular double star.During the Summer , Nu Sco is one of my regular target for binocular observing.Most recently I saw Nu Sco as double last week through my Baigish 10x50mm binocular.

Glenn
Thank you for clarifying an unanswered question I made on another forum.
About one week ago I incidentally stumbled upon Xi Sco while observing with my 60x700mm refractor.It was unknown to me until than.
Both pairs were split at 42x,using a 16.7 mm IOR Huygenian.

Another double-double to be added to the list is Gamma Delphini and Struve 2725 visible in the same field.
For my 60x700mm refractor ,Struve 2725 is quite close to the limit for this instrument.I split this recently at 93x/Clestron 7.5mm ''orange'' Plossl,but only because I knew before hand it is a double star.
It was not obvious at all.

Mircea


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ggalilei
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Re: Another other double-double new [Re: GlennLeDrew]
      #5970098 - 07/14/13 09:09 AM

I was looking (for my very first time) at Struve 2470/2474 just two days ago and was disappointed to see that it has lost the symmetric appearance it used to have.
What aperture/FOV may be needed to catch a view of IC 4592?


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GlennLeDrew
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Re: Another other double-double new [Re: ggalilei]
      #5970201 - 07/14/13 11:02 AM

Antonino,
Lost the symmetrical appearance they used to have? I wasn't aware of either variability or sufficient differential proper motion to result in any change of note over a human lifetime.

IC 4592 has very low surface brightness. Due this, and the large size of about 1.5 degrees, a large bino is your best instrument. Two eyes provide an increase in signal to noise of 41%, which can make the difference. I've glimpsed it with a 22X100 bino under a fairly dark sky (zenithal surface brightness of 21.4 magnitudes per square arcsecond) at my latitude of 45N. I'd love to see it higher in the sky than the 25 degrees it reaches here, where the contrast would be rather better. I'm not sure if any filter would improve the view, but maybe a broadband LPR filter could deliver a slight gain in contrast.


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ggalilei
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Re: Another other double-double new [Re: GlennLeDrew]
      #5970537 - 07/14/13 02:58 PM

Before looking for myself, I had found an old CN thread on Struve 2470/2474, from September 2007. The OP was edosaurusrex and asteroid7 posted an old sketch of this "mirror" double-double, but later sketched it again and it was not symmetric anymore. Another poster also sketched it and it wasn't symmetric. So, I was disappointed but not too surprised to see that the symmetry was lost. It was my very first attempt, so I'll have to double check that I was actually viewing the right pair, but it did look right. You might want to check it again.

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ggalilei
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Re: Another other double-double [Re: GlennLeDrew]
      #5970547 - 07/14/13 03:05 PM

I could try to catch IC 4592 in my Traveler. The 31mm Nagler gives about 20x and 4 degree FOV, with 5mm exit pupil.

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ssmith
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Reged: 06/28/12

Loc: Colorado
Re: Another other double-double new [Re: ggalilei]
      #6003657 - 08/02/13 06:09 PM Attachment (19 downloads)

Hi-

I recently took a star trail photo of 2470/2474 and it
sure looks symmetrical to me.

Photo attached.


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ggalilei
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Re: Another other double-double new [Re: ssmith]
      #6003934 - 08/02/13 08:50 PM

Right you are! I must have been looking at a different set of doubles then, nearby and similar in general appearance. And I think the same thing may have happened to others who sketched it asymmetrycal. Will definitely have to try again.

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Tyranthrax
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Re: Another other double-double new [Re: ggalilei]
      #6006826 - 08/04/13 11:24 PM Attachment (14 downloads)

Since you guys were talking about Nu Scorpii, I got a picture, but is this right? or was I going the wrong direction? If I zoomed in too close I would lose the overall big scope of it. So I took to longer out shots with one star, lower right as a reference point, then took the bottom two. Registacked em both and stitched it together so it keep the proper observational distance. Lot more work to get the field of view. in these. So is this right or am I in the wrong spot? It was the only 4 together I saw, It was kinda late and thought I might have missed the best time to see it. the stars came out just plain white with no color, it was low in the horizon. I'm guessing the lower right was the double I didn't get to split?

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ggalilei
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Re: Another other double-double new [Re: Tyranthrax]
      #6006867 - 08/05/13 12:03 AM

My impression is that the pair at the top left is likely nu Scorpii (about 40" separation?). Each of them would be a close double, not visible here. Not sure that that's the correct interpretation though.

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Tyranthrax
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Reged: 04/22/13

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Re: Another other double-double new [Re: ggalilei]
      #6006972 - 08/05/13 02:11 AM

I have no idea. I couldn't fit these 4 here into my camera, but they were the only 4 stars in the area. I had to take 2 images here and stitch them together , using the lower right as an anchor point. DO they make a piece that goes in front of the camera to widen the FOV?

I am more than happy to go back and do it a little closer, I wanted to make sure I was looking at the right thing.


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ggalilei
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Re: Another other double-double new [Re: Tyranthrax]
      #6007198 - 08/05/13 08:23 AM

I can't help, since I don't know a thing about astrophotography. To get the four components, though, you need reasonably high magnification, probably around 75x to split the dimmer component and perhaps around 150x to split the brighter component. It would become quite difficult to catch all four in a photo, I imagine.

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ggalilei
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Re: Another other double-double new [Re: GlennLeDrew]
      #6007205 - 08/05/13 08:26 AM

Thanks to all for the correction. I looked at Struve 2470-2474 last night and indeed is close to symmetrical, quite pretty and easy in the AT66ed at about 55x. I was evidently looking at some other star system on my first attempt.

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Tyranthrax
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Reged: 04/22/13

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Re: Another other double-double new [Re: ggalilei]
      #6007363 - 08/05/13 10:34 AM

So is the quad the top two or is that one of the doubles and I missed the other? I couldn't see any others but it was lowin the sky and the air plays tricks on us.

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ggalilei
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Re: Another other double-double new [Re: Tyranthrax]
      #6007379 - 08/05/13 10:41 AM

I think that the top two are the quad, except that their companions are not visible because each double is very tight. Hopefully someone with more experience will confirm or correct this tentative conclusion.
P.S. Can you estimate the magnification used in that photo?


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Tyranthrax
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Reged: 04/22/13

Loc: Reno, NV
Re: Another other double-double new [Re: ggalilei]
      #6007430 - 08/05/13 11:24 AM

The magnification is not very high at all I'ld have to pull the specs up on zoomed out. I nkow zoomed it Orion said it was like a 5mm eyepiece, I stayed out as far as possible to get all 4 that I saw in the picture, just in case. I am not sure when zoomed ut the specs aren't that clear I'll ask orion in a bit

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ggalilei
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Re: Another other double-double new [Re: Tyranthrax]
      #6007519 - 08/05/13 12:21 PM

There is a star field similar to that in your photo just slightly west of nu Scorpii. So, you may have missed the quadruple star altogether. I suggest viewing the star first, at about 100-150x, and you should see a triple star, one brighter and two much dimmer and close together. That would be nu Scorpii. Then take a picture.

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Tyranthrax
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Reged: 04/22/13

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Re: Another other double-double new [Re: ggalilei]
      #6007785 - 08/05/13 03:03 PM

TY Sir! I'll see if I can nail it tonight! GoTo get's finiky. I appricate the directions

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ggalilei
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Re: Another other double-double new [Re: Tyranthrax]
      #6011104 - 08/07/13 09:35 AM

I looked at nu Scorpii again last night. It looks like you did get it in the picture you posted, at the top left. Because of low magnification, it doesn't show its quadruple nature.

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