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Ready for shoot out


RobertI

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Two scopes set up and ready for tonight’s observing session. Tal 100R on a Skytee and Heritage 130P on a SkyProdigy. Hoping to view some nice doubles in and around Bootes and possibly some DSOs if sky is dark enough. 👍

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Final scores just in and the result is.....drum roll......pretty much a draw! Full report tomorrow but based on a very limited set of objects and similar mags (approx 130x) , the frac was very slightly better at splitting doubles (although I didn’t try really close splits) with slightly better ability to show colour contrast , and the Newt had very slightly better resolving on globs and slightly brighter view. Frac seemed to show a darker sky and the Newt had, surprisingly, tighter stars, but this didn’t translate into better splitting ability. More tomorrow. 

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Interesting. My money would have been on the 100R for tight stellar points and sharpness, and on the 130 for colour (true colour, not CA of course 😁) and brightness.

They sound pretty evenly matched🙂.

Dave

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I've got a 130P and it is surprisingly capable. Even vs the Tak 100 the extra aperture shows on globs.

I've had a couple of TAL 100RSs and they did vary a bit in sharpness, one quite alot better than the other. I guess it's possible something is out of line with yours?

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Full write up of the evening's activities, I have to say it was one of the most trouble free sessions I have had, probably because I took the time to prepare properly. Once the clouds rolled away, the conditions were excellent, with reasonably good seeing and excellent transparency. The SkyProdigy self aligned and was (mostly) spot on with the gotos all night. Even the neighbours played ball! At 11pm the sky was still very light but by midnight was nice and dark (by summer standards).

Equipment:

  • Tal 100RS Achro with with Hyperion 10mm e/p + 14mm tuning ring (and cheap Celestron prism diagonal) giving 140x
  • 130P Hertitage Newt with 5mm BST giving 130x.

The difference in magnification and use of a prism diagonal in the Tal may well have made the comparison a bit pointless (opinions welcome!), but observations were as follows:

  • Izar - Beautiful coloured double, with bright orange primary and significantly fainter whiter secondary separated by 2.9". Both scopes split the pair easily, but was cleaner in the Tal with a more significant black line between the two (additional magnification coming into play here?) but also still easily and immediately split in the 130P. The orange of the primary was more obvious in the Tal, looking whiter but still light orange in the Newt. The colour contrast between the two was also more obvious in the Tal. It should be noted that everything in the Tal looks more yellow, I guess a feature of being an Achro? I don't know if there is a problem with the Tal or the diagonal, but the Izar showed a redenning on one side, a CA type effect, but only to the west of the FOV. Not really noticable on any other stars during the session.
  • Xi Bootes - Another fine double with a yellow primary and redder secondary separated by around 5". This time the colour difference was easier to discern in the Newt.
  • Pi Bootes - Two white components, one slightly brighter than the other, separated by 5". Very nice in both scopes.
  • Epsilon Lyrae - Again easily split in both scopes, but the Tal showed a cleaner darker line between the closer and more difficult pair.

Generally the stars appeared 'tighter' and whiter in Newt but the sky background was brighter and resulting contrast between object and background slightly less good. I don't know if this was a feature of the slightly lower magnification, particularly the 'tighter' stars?

A couple of well know DSOs to finish the shoot out:

  • M57 - Surprisingly bright in both scopes, with brightening towards the outer edge of the ring and and 'milky' inner hole. Very slighly brighter and noticably whiter in the Heritage but little to choose between them.
  • M13 - Again, a very close run thing, with both scopes revealing myriad stars, especially with averted vision, with so many on the edge of being resolved, but the Heritage was the  winner here with slightly more stars resolved.

In terms of using the scopes, they couldn't be more different. The wobbly helical focusser of the Heritage was a distinct pain in the bum, making accurate focussing really hard as the the star raced around the FOV every time the focusser was touched, not helped by the slightly wobbly mount. The Tal by comparison was an absolute joy to focus.

For the first time I used a stool to observe with the Tal and I have to say it was really relaxing and something I shall do in future. Observing near the Zenith was a pain in the bum (or back) and the slow mo controls were just about within reach above my head - not really a sustainable way to observe. No such problem with the Newt which from a standing position always seemed to have the eyepiece available to the eye, and best when near the zenith.

So in conclusion both scopes gave great results optically, though I think the Tal was perhaps operating a bit below what it should. They couldn't be more different but they are fun to use and either one would be fine as my only scope. As usual I am looking at how to make things even better, and I have concluded the best next step would be........a 100ED or 120ED on an AZ-EQ5!!! 😁

Edited by RobertI
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  • 3 weeks later...
12 hours ago, Roy Challen said:

Nice report! Perhaps some of the colour experienced in the Tal was due to the cheap prism diagonal? I would try a decent mirror diagonal and compare.

Thanks Roy, yes I had come to the same conclusion, I do have 2” mirror diagonal which I have used with the Tal and I don’t recall the same problem, but I didn’t use it on the night as I couldn’t get enough in focus with the Hyperions (the focus point is a long way in on the Tal). I really need to get a decent 1.25” mirror diagonal for it with a shorter light path - I have a couple on my list. 👍

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