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Posts posted by John
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Nice one Geoff !
Won't be like that from here - 10 degrees elevation means waiting for the star to appear in a gap between the surrounding house roofs
Glad you got it though
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4 hours ago, Ags said:
John I know you like to use the 7.2-21.5, but it doesn't have a home in either case?
It's at the very top left of the 1.25" case. It's rather long top dust cap has disguised it !
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Amazing how these threads develop a life of their own and often an extended one, even after the OP has long stopped following them.
I can't remember when I last posted in this one so here are my 2 cases. The 1.25 inch case includes the Nagler 2-4mm zoom rather than the 3-6mm that Neil has just bagged. I think the 2-4mm is out of production now ?. The filter in the 1.25 inch case is a Japanese made Meade 4K Narrowband (UHC equivalent). The filters in the 2 inch case (2nd photo) are a 2 inch Lumicon O-III and a 1.25 inch Astronomik H-Beta. There is some overlap with these eyepieces which I explain by reasoning that some are used for outreach purposes but is really explained by the fact that I'm still an "occularholic"
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Thanks for the responses folks - I've been clouded out for the past few nights so I'm dredging up old observations to discuss !
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Last year I managed to split Antares for the first time. It is a very challenging double star for three reasons:
- The separation between the 2 componant stars is around 2.5 arc seconds.
- The componant stars are markedly different in magnitude, the primary being magnitude 1.0 and the secondary magnitude 5.4.
- From the UK, Antares does not rise far above the horizon. Currently it's reaching around 12 degrees above the horizon from where I observe. Thats a lot of atmosphere to peer through.
The split that I got was with my 130mm triplet refractor at 300x. While there was quite a bit of distortion and scatter created by the low altitude of the star, the secondary star could clearly be seen to have greenish tints compared with the orange/red of the primary. While challenging I don't think it was quite as tough as splitting Sirius but it's not far off that.
With Antares gradually becoming more favourably positioned at a reasonable hour now, I'm going to have another shot at it when a suitable opportunity comes along. Jupiter lies not far from Antares as well so another good reason to search out a clear southern horizon at around 1:00 am.
I'll be interested to hear of other folks Antares splitting exploits too
Antares is quite a bit larger than the Sun as this diagram indicates
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When I had a PST and a Lunt 50 I found that a zoom eyepiece was a great tool. Like Mark, I rarely used more than 12-15mm with these scopes.
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4 minutes ago, Stu said:
....If out focus is the issue then presumably if the op winds the focus all the way out then pulls the eyepiece out slowly it should come to focus?
Thats worth a try.
The focus mechanism of the stock PST can have issues as well:
https://www.cloudynights.com/topic/571477-trouble-with-pst-focus/
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The only thing that I can think of that might prevent a Tele Vue plossl coming to focus is that the TV plossls reach focus around 8mm further outwards than many other eyepieces. If the focusser mechanism of the PST in question had an issue of some sort (it works by moving a prism within the body of the scope I seem to recall) then that might prevent it being able to allow the focal plane of the eyepiece to reach that of the scope optics.
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I would probably deal with that rather than leave it. At least a corrector lens is a singlet so the issues will be either on one side of it or the other. When they get between the lenses in an air spaced optic the cleaning exercise gets quite a bit more complex.
I've cleaned an SCT correct in a similar state to that by removing it from the scope (taking note of the alignment marks on it's edge) and using Baader Optical Wonder Fluid and the micro fibre cloth. It came up pretty much pristene.
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I've used my Hershel Wedge for outreach events involving children quite a few times including most recently at a local junior school where over a period of 4 hours around 300 children and staff observed the Sun with it.
I do go to great lengths during these sessions to empasise that the equipment being used is specially designed to enable safe solar observing and on no account should anyone look at the Sun with any sort of optical device, including binoculars. We have posters up to this effect and also repeat the message as each group comes forward and again whenever it seems apt to repeat it.
It is a very responsible business that I take very seriously but the enjoyment that the children get from their solar views and the subsequent discussion we have on our nearest star are very rewarding from my point of view and theirs judging by the feedback
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2 minutes ago, Adam J said:
No I am quite interested in seeing things like the transits or partial eclipses but the sparsity of such events does not justify buying a solar wedge and my concerns over safety mean I dont want to use solar foil.
I have a masters degree in laser physics and people I know have been involved in laser related accidents resulting in eye damage, that is a very similar type of damage and so I am hyper aware of the consequences and it makes you take great care with your eyes. I dont need multiple things in my life that can potentially blind me even if it is unlikely.
Adam
Fair enough. Would you look through someone elses Herschel Wedge setup ?
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1 hour ago, Adam J said:
no my main interest by far is DSO imaging anyhow and so I would not want to invest any cash into solar observation just for transits.
So it's more of a lack of interest in solar observing than concerns over the safety of the equipment available to do it ?
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I feel that the Herschel Wedge is a pretty safe approach. Even if, in the most extreme circumstances, the wedge falls out of the scope, all the light and heat goes straight out of the back of the scope and not towards the eye at all.
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Solar projection works fine but you really want to use non achromatic eyepieces which don't use cemented lenses. The Huygens or Ramsdens are good because they are a simple design comprising of 2 singlet lenses. With solar projection the heat of the suns rays at focus passes through the eyepiece optics and the heat can melt the cement that holds lenses together.
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A small slice of the L-chondrite meteorite Aba Panu that fell in Nigeria on April 19th 2018. Collected within days of the fall so not subjected to 100s or 1000s of years of the Earth's weather. Fresh from the birth of the solar system and newly arrived on this planet !. The link below is to the Meteoritical Bulletin entry for this meteorite:
https://www.lpi.usra.edu/meteor/metbull.php?code=67799
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Great report Ed and congrats on getting Zeta Herc !
I've had a mild obsession with that binary star for sometime now. I first managed the split with with a 150mm F/8 refractor, then eventually with my ED120 and now I've managed it with the Tak FC-100. It's a challenging pair alright with it's closeness and uneven brightness and a stern test of observer, conditions and equipment.
I agree that it's when you are observing targets that push towards the limits that quality optics show their worth.
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1 hour ago, Paul73 said:
You get used to it! It does feel really odd to start with.
Paul
I hardly do much solar observing myself - mostly then it's outreach. I'd get fed up of explaining why the sun was green I think !
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I use this one on my Vixen ED102SS - it's an option from Vixen:
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41 minutes ago, Piero said:
I guess it is personal. I tried both the polarising and the solar continuum, and I prefer the latter, particularly on granulation. The green sun does not bother me though.
The green tint would not be my preference but that is, as you say, personal.
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Another vote for the Pentax XW 7mm here. I've found it as good as the Baader GO 7mm in peformance but with a lot more observer comfort. A lot more costly as well of course.
I've owned and used all the UWAN / Nivana focal lengths EXCEPT the 7mm but I don't see any reason that it would not be a very nice eyepiece. I found the 4mm Nirvana an excellent high power eyepiece. I didn't experience the 7mm UWAN / Nirvana because I had a 7mm T6 Nager at that time which was another fine, though expensive, eyepiece.
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Welcome to the forum Andy
If you want to get a "hands on" feel for some scopes and talk about them, Bristol Astro Society have regular open viewing nights at our observatory at Failand. There are usually a few different scopes there plus the society 12 inch in it's dome. We announce such events at the bottom of our home web page:
http://www.bristolastrosoc.org.uk/www/index.php
This forum will be a great source of advice and info as well - lots of experience here
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I use a Lunt 1.25 inch Herschel Wedge with an integral ND 3.0 filter and a single polarising filter on the eyepiece which gives adjustable brightness (by twisting the eypeiece). I have heard that replacing the single polarising filter with a Baader Continuam Filter might increase contrast of features but the reported green colour tint puts me off going for that.
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10 hours ago, shirva said:
Thanks for the update guy's,, real pity it's taking so long to get to beta testing,, you would have thought that a prototype would have been tested by a impartial astronomer and recommended any modifications before sending out a batch to be tested,, I would be a bit worried if it were me buying it especially with the cost involved.
I hope they deliver better than what was advertised and you can get some usage before dark night's start creeping in.
I agree - I would like to see this scope tested by experienced astronomers with no financial or other interest in the product. My guess is that it might be good at some things but very average at others but you will need experienced observers to put it through it's paces on a wide range of targets including targets that really push it's performance capability.
Comparisons with conventional equipment of similiar aperture would be good as "yardsticks" as well.
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Antares Challenge
in Observing - Discussion
Posted
Still waiting for a clear sky here ......![:rolleyes2: :rolleyes2:](//content.invisioncic.com/g327141/emoticons/default_classic_rolleyes.gif)