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azure1961p
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Reged: 01/17/09

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Re: 90 Herculis new [Re: Sasa]
      #6073829 - 09/10/13 08:01 PM

Amazing how different our results can be. 2 was a tough but to crack!


Pete


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fred1871
scholastic sledgehammer


Reged: 03/22/09

Loc: Australia
Re: 90 Herculis new [Re: azure1961p]
      #6073933 - 09/10/13 08:58 PM

Quote:

For me it was a matter of summer haze and light pollution blotting it out.
Steadiness in the air was rather lousy quite frankly. Instead the dryer fall-like air it was held with certainty at 364x simply because the sky was darker - transparent. I'm not sure Id hold this double with any kind of elevated appreciation had I mag 6 sky's. as mentioned in a previous post : 2ES Vulpeculi is far more challenging - and under a better than mag 6 sky.

5.48-9.28v @ 1.8" versus 90 Herculis: 6.17-8.38v @ 1.6"

The 2/10ths greater sep of 2ES hardly makes it comparable. At anyrate I would never contemplate this one from my condos compromised sky's.

Pete




Pete, where are you getting these numbers from? They're certainly not WDS... maybe some software package that claims superiority to the primary source? (the primary source is WDS, as the compilation of primary materials).

Earlier in this thread, John (7331Peg) gave the current data for 90 Her - mags 5.28 and 8.76 (Dm 3.5) at 1.6" (2009).

And the WDS gives for 2 Vul, mags 5.43 and 8.75 (Dm 3.3) at 1.7" (2009).

So these doubles are not wildly different in brightness, delta-m, or separation. So it might be expected that they'd be roughly similar in splittability. The varying difficulties people have suggests to me differences in seeing conditions as the primary factor.

Incidentally, 2 Vul (BU 248) has the primary star as ES Vul, a variable star designation. The WDS adds a note to this effect, saying that it's a Beta CMa-type variable (sometimes known as a Beta Cephei type - and not to be confused with classical Cepheids). That means the magnitude variation will be small - Sky Catalog 2000 lists a variation of 0.06 magnitudes, so not much to worry about there.

Anyway, the main point I wanted to make is that we need to stay with the best data we currently have in these discussions, as that helps to keep it meaningful rather than confused and confusing.


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azure1961p
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Re: 90 Herculis new [Re: fred1871]
      #6074178 - 09/10/13 11:47 PM

Agreed. Too trusting with Sky Safari but Im getting better at checking with WDS. Still the WDS LISTS Delta Equulei as being over 300" which has to be an error as the tidy 5.7 year orbit is .35" at best . I'm guessing its a typo on WDS' part. I see no proper designation for this tight double at WDS but in this case it would appear Safari is the right one - as is dated Burnhams.
I'm surprised now then that 90 Herculi is MORE DIFFICULT that 2 V - and I worked so hard at getting 2. I'm guessing its a couple things. This is the first summer Ive made a go at doubles with fulltime fans running and ports by the primary to allow the heat to escape from the side as opposed to funneling up the tube. I NEVER have seen as clean a star pattern as this summer - splitting epsilon lyrae at 70x was a first EVER in the twenty years Ive used this reflector. I'm guessing the lack of scattered light to flaring is paying off here. The other thing is the more I observe the more I see so maybe I put 2ES on too high a pedestal. I'm flabbergasted its easier than 90 H.

I think its the fans Fred.

Pete

PS: I'm amazed at Alexander's 110mm split on these doubles. It was tough for my 8".


Edited by azure1961p (09/11/13 12:00 AM)


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Sasa
professor emeritus


Reged: 11/03/10

Loc: Ricany, Czech Republic
Re: 90 Herculis new [Re: azure1961p]
      #6074568 - 09/11/13 08:37 AM

Pete,

you know its Zeiss... Now seriously, splitting 2 Vul was quite difficult in AS110. At 183x and 236x I strongly suspected the secondary at PA~130deg. I convinced myself at power of 275x. I also estimated the distance to be about the radius of the 1st diffraction ring, i.e 1.7". Later at home I found out that PA agrees well.

Now, since 2 Vul and 90 Her are so close on paper, I'm wondering why I did not split 90 Her as well recently. The conditions were quite similar based on the notes in my logbook...


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azure1961p
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Re: 90 Herculis new [Re: Sasa]
      #6074645 - 09/11/13 09:27 AM

2ES BY Name is variable so maybe that had something to do with it?

Pete


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fred1871
scholastic sledgehammer


Reged: 03/22/09

Loc: Australia
Re: 90 Herculis new [Re: azure1961p]
      #6078182 - 09/13/13 03:07 AM

Pete, I'll quote myself from my note earlier in this thread:
Incidentally, 2 Vul (BU 248) has the primary star as ES Vul, a variable star designation. The WDS adds a note to this effect, saying that it's a Beta CMa-type variable (sometimes known as a Beta Cephei type - and not to be confused with classical Cepheids). That means the magnitude variation will be small - Sky Catalog 2000 lists a variation of 0.06 magnitudes, so not much to worry about there.

With such a small magnitude variation, there will not be any significant effect on resolvability from brightness changes.


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jrbarnett
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Reged: 02/28/06

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Re: 90 Herculis new [Re: mikey cee]
      #6079604 - 09/13/13 11:21 PM

I separated the pair in a 127mm f/9 ED doublet at around 180x without much difficulty several years ago. Haven't checked it out since then. Reports of resolution in a 101mm scope have me now itching to go after it in a 111mm triplet.

I wonder how small can you go and still manage the split?

Regards,

Jim


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azure1961p
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Reged: 01/17/09

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Re: 90 Herculis [Re: jrbarnett]
      #6079608 - 09/13/13 11:25 PM

Thanks Fred, as always, appreciated.

Pete


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rayden68
member


Reged: 03/16/12

Re: 90 Herculis new [Re: azure1961p]
      #6126123 - 10/08/13 11:35 PM

A very clear night so I was waiting to try this one used my ES ar152, went 396x and could see a bump or flash on the bottom right. Put in a 4mm with a Barlow and again a bump or flash and maybe a dot? Checked the position and that's where it should be. I will put it down as a good try. Just wasn't distinct enough to claim a dead to rights victory. I want to try again on a better night or more aperture or both!

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Bill Boublitz
super member


Reged: 05/04/13

Re: 90 Herculis new [Re: rayden68]
      #6126220 - 10/09/13 12:54 AM

By all means, try again. It sounds like you're getting there. This is a challenging, somewhat fugitive pair. What aperture are you working with?

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rayden68
member


Reged: 03/16/12

Re: 90 Herculis new [Re: Bill Boublitz]
      #6126482 - 10/09/13 08:08 AM

A was using my 152mm refractor.

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payner
scholastic sledgehammer
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Reged: 03/22/07

Loc: Bluegrass Region, Kentucky
Re: 90 Herculis new [Re: rayden68]
      #6137530 - 10/14/13 05:32 PM

On 8/23/2013 I split 90 Herculis with a RuMak 228/3199 using a 5 mm LE eyepiece. I recorded this observation as very tight clean split (dark line between the stars). Seeing was recorded as 3/5.

On 10/11/2013 I split this pair with a RuMak 228/3100 using an 8 mm eyepiece. Seeing that night was a 4/5. I noted the primary as cream and the secondary white.

Best,
Randy

PS- If skies and opportunity allow, I want to try with a FS-152 refractor before it gets too low this year.


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