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90 Herculis

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#1 mikey cee

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Posted 29 June 2013 - 12:55 PM

What gives here? This is a toughie or my transparency sucks. My book says magnitudes 5.8 and 9.2 with a seperation of just over 1.6"! But that is a hech of a contrast stretch. :confused: Mike

#2 7331Peg

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Posted 29 June 2013 - 02:05 PM

Must be your transparency or seeing conditions -- you should be able to get that one with your ten inch f/11 !!!

The separation you listed is correct, but the magnitudes are 5.28 and 8.76. Here's the current data on it: 90 Her (Bu 130).

That's one I haven't looked at -- should be clear tonight so I'll pay it a visit.


John :refractor:

#3 fred1871

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Posted 29 June 2013 - 09:48 PM

It shouldn't be a transparency issue with the magnitudes John has quoted. Seeing will be an issue with delta-m of 3.5 (big brightness difference) at only 1.6". You've got enough aperture; it should be an issue of air steadiness. I'd expect 6-inch to 8-inch scopes should manage 90 Her in good seeing.

It's one of the Haas project stars, and observations (successful ones) are currently listed for apertures down to 101mm, which is extraordinary if it's a definite, not a spurious, observation - sometimes doubles look as if they're showing but they're not - honest but spurious observations can happen. The resolution reports have 3 recorded successes with 150mm; that's clear enough as an indication of what's possible. Beyond that???

I'm planning another attempt on 90 Her myself, but as it rises only around 16 degrees from the horizon where I am, it'll take unusually good low-altitude seeing to detect as a double. Even when doubles are high in the sky, air steadiness is a make or break issue.

#4 Nucleophile

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Posted 29 June 2013 - 10:20 PM

It's one of the Haas project stars, and observations (successful ones) are currently listed for apertures down to 101mm, which is extraordinary if it's a definite, not a spurious, observation - sometimes doubles look as if they're showing but they're not - honest but spurious observations can happen. The resolution reports have 3 recorded successes with 150mm; that's clear enough as an indication of what's possible. Beyond that???


Last year, I reported a split of this object at 171x using an 8 inch reflector in support of this project.
Give it another shot I say.

#5 mikey cee

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Posted 30 June 2013 - 10:46 AM

Finally I bagged the companion last night near the zenith. No wonder it's difficult a combination of transparency and super steadinous was needed to reveal the little devil. With the 10" F/11 and 815X the pin pric comas sat just outside the first broken difraction ring and right there at I guess between the 3:00 and 4:00 position. Went to my Burnhams and looked it up. Position angle was 116°. I hit it on the mark. IMHO this baby is probably not going to be seen in anything less than 8" and of long focal length. First of all it needs light because it is so tiny and faint and secondly it needs a good deal of image scale. Without those two things going for you it's out of reach. I tried my Jaegers 6" F/8 at 212X and the image scale was too small to clearly get rid of the spurious effects of the primary. Either that or my eyes are failing me. ;) Mike

#6 WRAK

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Posted 30 June 2013 - 04:57 PM

Last year I tried with 120mm and 140mm refractors without success. With good conditions it should be resolvable with a 5" aperture - will try again soon and report.
Wilfried

#7 labmand

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Posted 02 July 2013 - 09:38 PM

No luck last 2 nights with 6" sct F10 all the way up to 638x
may need to go bigger

#8 Nucleophile

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Posted 03 July 2013 - 12:48 AM

I reexamined this one tonight with the 8 inch reflector with the following results:

197x: just resolved; secondary as a tiny orange bump on the yellowish primary
230x: more clearly seen as resolved; secondary is tiny
276x: split!

#9 ggalilei

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Posted 16 July 2013 - 10:47 AM

My very first try last night, with a Z10. No trace of the companion, even at 500-600x (Nagler 2-4mm zoom). I wonder though if I may have been looking at the magnitude 6 star very close to 90 Herculis instead? I was getting a gorgeously clear view of mu Cygni at 200x (4.8 & 6.1 at 1.6") and even lambda Cygni seemed to show up for brief moments (4.5 and 6.3 at about 1"). Will have to try again.

#10 mikey cee

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Posted 16 July 2013 - 11:55 AM

I'm not surprized in the least at the problems you folks are having. It's not an orange "bump" either. My 10" refractor shows a white companion hidden just beneath the broken first disc ring. I'm wondering if it is a variable star. :shrug:It just seems much dimmer than 8 mag. Maybe it's deceiving because of the 5 mag. primary. All I know is it is somewhat "difficult" in my big refractor. I don't see how a 6"-8" scope at high power to seperate 1.6" can be able to detect this little devil. It truly needs exceptional steadiness in the air. :help: Mike

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#11 Nucleophile

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Posted 16 July 2013 - 05:12 PM

According to the observations I noted previously, it wasnt that difficult for me with my 8 inch reflector. I stand by the "bump" note as this best described what I saw. I also stand by the "tiny" comment--but dont know how to gauge magnitude from that. :grin: As far as the orange color, every tiny companion is orange to me. :rainbow:


It may be a while for good skies, but I will be sure to try this one for a third time with the 8 inch to make sure I am not nuts. JK---I know what I saw (both times). I will also give it a shot with the 15 inch stopped down to unobstructed 6 inch.

Thanks for the pic of the bino'd 'fractor Mike, I bet the views are "stellar" :roflmao:

#12 Bill Boublitz

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Posted 14 August 2013 - 12:45 AM

Got a chance to observe 90 Herculis last week for the first time this year.

2013:08:05:04:35 UT. Using 101 mm refractor, primary a golden-yellow, companion a medium to light orange, well notched in P.A. 120 degrees (approximate). Unmistakable duplicity. LM=5.0 w/direct vision, seeing=excellent, Moon not present. Magnification: x225, Field: 0.28 degrees. [M8 and M20 complex easy with naked eye. Skies as good as it gets for this location.]

Had split last year, with reservations. Challenging pair. Wanted to repeat observation to be certain. No question; this one possible with 4" aperture.

#13 azure1961p

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Posted 14 August 2013 - 07:37 AM

I'm not surprized in the least at the problems you folks are having. It's not an orange "bump" either. My 10" refractor shows a white companion hidden just beneath the broken first disc ring. I'm wondering if it is a variable star. :shrug:It just seems much dimmer than 8 mag. Maybe it's deceiving because of the 5 mag. primary. All I know is it is somewhat "difficult" in my big refractor. I don't see how a 6"-8" scope at high power to seperate 1.6" can be able to detect this little devil. It truly needs exceptional steadiness in the air. :help: Mike


An 8" will resolve an even greater magnitude variation at that seperation but as said, it needs high power and a good Pickering 9 night. At least with Pickering 7 it wasn't there. I went this same route with 2Es Vulpeculi where it finally only resolved at 433x on a 9/10 Pickering night.

Pete

#14 R Botero

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Posted 04 September 2013 - 07:38 AM

As per some posts in the 99 Her thread I have had difficulty splitting this one. Last night I had exceptionally good seeing but I didn't get a clear split at 450x in my 6" f/7.5 refractor. I thought I had seen it within the main diffraction ring of the primary earlier in the summer but I could not confirm it last night.

Roberto

#15 mikey cee

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Posted 04 September 2013 - 09:55 AM

With a 10" refractor it isn't a piece of cake by any means but it is visible on just about any random night I check it out tho'. ;) Mike

#16 magnus

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Posted 05 September 2013 - 09:21 PM

Had a try on this one this night with my MK66 MAK. Negative obs.Used up to 360X.Seeing 7-8/10P. Will try again before Hercules is too low alt. and check if collimation is spot on, I suspect it`s not.
Still this is great fun!

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#17 WRAK

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Posted 10 September 2013 - 02:16 AM

Despite not this good conditions (Pickering ~5) I tried again with my 140mm refractor - not even a hint of anything.
Tried also 99 Her, got the impression of a 12 o'clock elongation (wrong position) and once or twice a flicker in the diffraction pattern at 10 o'clock (wrong position).
Very classic negative result.
Wilfried

#18 Sasa

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Posted 10 September 2013 - 03:09 AM

Couple of days, I also tried to look at 90 Her. This time with 110mm refractor. No hint of secondary as well.

#19 azure1961p

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Posted 10 September 2013 - 07:18 AM

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

#20 Sasa

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Posted 10 September 2013 - 04:22 PM

Pete, for me it is opposite. I cracked down 2 Vul in 110mm refractor last year. It was hard, but the secondary was clearly there. I had no luck with 90 Her.

#21 azure1961p

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Posted 10 September 2013 - 07:01 PM

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


Pete

#22 fred1871

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Posted 10 September 2013 - 07:58 PM

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. :grin:

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.

#23 azure1961p

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Posted 10 September 2013 - 10:47 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".


#24 Sasa

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Posted 11 September 2013 - 07:37 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...

#25 azure1961p

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Posted 11 September 2013 - 08:27 AM

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

Pete






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