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Sunshine

Just no Splitting These Two

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Posted (edited)

Zeta Hercules and Pi Cepheus, the thorns in my side, even on a night of good seeing. Using my 115mm frac and my 3.5mm Pentax, at 230x, I can’t even discern the snowman effect. Are these two doubles beyond the resolving capabilities of my scope?. By comparison, Delta Cygni I can make short work of with the 3.5mm XW but, not those two buggers, they’ll be the end of me. Maybe the issue is (in my case) i just need a little more power? maybe somewhere in the 260x range i may start to see them as a snowman or maybe even split. As of now, adding my Powermate to my 3.5 gives far too much power, over 500x which is useless. 

I SHALL SPLIT THEM!!!

Edited by Sunshine
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Definitely within the grasp of your scope I’m sure. Perhaps some more power needed as you say. I struggled for years with this Zeta Herc, then finally did it with my 210 Mewlon and 8” f8 dob and now find it much easier because I know what I’m looking for.

I have split Zeta Herc with my 4” Vixen Fluorite a couple of times now, perhaps you are looking for the wrong thing. By that I mean in smaller scopes it is not like seeing two clearly defined airy disks, but is more a brightening on the first diffraction ring. I can’t recall what the lowest power I used was, but potentially it was in the x250 to x300 range with my Nagler zoom. EDIT just found my post which says it was at x300.

John has posted a very good sketch of it somewhere which may help, done with a 120ED so should be similar in your scope. Keep trying, you will get there!

 

 

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This is John's sketch:

zherc.jpg.657938245b912ee4acf3d02d5bd16877.jpg.f2b8a7a297d40b4f6a48ca523a4d0c3b.jpg

 

All credit to John -sorry I can't work out how to link another thread which would show the context!

This sketch was the key to my cracking Zeta Herculis after many failed attempts. It accurately depicts what you can expect to see and the compass points help to confirm the position of the companion. Basically, in my scope at least, it doesn't look like a 'normal' double star 

Good luck 

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I first managed Zeta Herc back in 2013 with my ED120. Kerry has kindly posted the 2016 version above and below is a re-vamp from May this year. As you can see the position angle has changed a bit. I think the gap is a touch wider now as well but it is still a challenging split:

zherc2020.jpg.a68dc4c3f6ac5b9f8291bb235327f256.jpg

 

 

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PS: you don't really get a "snowman" or "peanut" effect with this one. The secondary star looks rather like a tiny blob of dirty blu-tak stuck onto the diffraction ring !

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In many ways it looks a bit like Izar through a small scope (60mm ish). They show larger airy disks and the secondary is placed bang on the first diffraction ring.

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Well, thanks a million, I may well have seen it and didn’t know! expecting a sight closer to what Delta Cygni looks like. Boy am I glad for you folks, This changes everything, I do need some more power, it looks like 230 will not do it. Many thanks, It will be a load of fun reading these two linked posts.

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4 hours ago, John said:

I first managed Zeta Herc back in 2013 with my ED120. Kerry has kindly posted the 2016 version above and below is a re-vamp from May this year. As you can see the position angle has changed a bit. I think the gap is a touch wider now as well but it is still a challenging split:

zherc2020.jpg.a68dc4c3f6ac5b9f8291bb235327f256.jpg

 

 

John now that the secondary is at 90 degrees due East the view in A Newtonian will be the same - although South will be at the top. I think I am correct?

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4 minutes ago, Mark at Beaufort said:

John now that the secondary is at 90 degrees due East the view in A Newtonian will be the same - although South will be at the top. I think I am correct?

Yes, I think that is correct Mark.

 

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Posted (edited)
6 hours ago, Stu said:

In many ways it looks a bit like Izar through a small scope (60mm ish). They show larger airy disks and the secondary is placed bang on the first diffraction ring.

image.png.1e917479fbdfcb455798084d18474c8e.png

Stu, is this a diagram depicting the pups orbit around its parent? if so, i guess if theres a good time to have a go at it now is the time, considering the pups distance. Your post was a load of fun to read.

Edited by Sunshine

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26 minutes ago, Sunshine said:

image.png.1e917479fbdfcb455798084d18474c8e.png

Stu, is this a diagram depicting the pups orbit around its parent? if so, i guess if theres a good time to have a go at it now is the time, considering the pups distance. Your post was a load of fun to read.

Well, that’s Zeta Herc from the looks of it. The Pup is the secondary around Sirius (the Dog Star).

We have it easy at the moment, 1.4” separation compared with 0.5” in 2001. It gets a little easier still, 1.5” and starts to close down in 2029 so we’ve got a while until it gets really hard! (He says as if it’s easy at the moment!)

0B0B1A16-73E8-4040-A63F-0467B2661D06.png

A278D712-2435-405F-A0A7-5D3D974D943D.png

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If both component stars were the same brightness, Zeta Herc would be a relatively easy split but with the primary at mag 2.95 and the secondary at mag 5.4 it becomes a much tougher challenge.

Similarly with Sirius - the separation there is a pretty straightforward 10 arc seconds but the brightness difference between Sirius and "The Pup" is massive, the latter being 10,000 times dimmer than the primary.

 

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