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A question for a refractor geek regarding the TV-101


topacid
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i recently acquired the TV101 and i shot a few test frames on APSc and full frame. Athough it is a Petzval it still has funny looking stars in the corners of APSc and 1/3 of the full frame shots. I called televue and asked if the LCL1069 flattner (as i really do not want the 0.8 reducer, i love 540mm) will work well with the design. I had them admitting that although it is not listed as working with the TV101, it will work because it is generally the same optic train configuration. Now the question: has anyone here had any photographic experience with the TV101 ? And what flattners , if any, did you use. It is quite a nice scope and i am a bit reluctant to sell right now and go to the NP. i just wanna see what can this baby do for me now. Visually it s one helluva scope, and in photos the stars are nice and tight in the center but seagulls on the sides. Attached, lower right corner of my 5dii shot of comet lovejoy at full size.post-40857-0-44892900-1421108378_thumb.j

Thank you,

Vlad

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Looking at your image the stars in the middle and on the left hand side do look nice and round, the problem is the right hand and to me this does not indicate a fault with the optics of the scope but probably a tilt of the camera sensor to the optical axis. You ought to investigate  this first before jumping in for a flattener that may or may not work with a Petzval design. 

A.G

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i want to use their flattner, specifically designed for petzval. but  i am asking if anyone had any experience with those. this lower right is symmetrical with the upper left . Actually i did have some tilt induced by my adapter.  but aside from that, i did run ccd inspector on the whole image. flatfield my otter, maybe for 2/3" ccds they use to make back in the day

post-40857-0-89052700-1421111119_thumb.j

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I noticed the same thing with mine, trying to use a full-frame Nikon D700 to have a dabble at imaging with it.

Spoke to a nice old chap called Al asking about the image circle size and he basically said, 'It's not designed for full-frame, NP101 (or maybe it was NP101is) is' 

Didn't bother me unduly as I'm mostly visual anyhow and as you've found, it's a lovely scope for that. 

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Yeah, digital is very critical, if the could get away with it on film, the ccd kills this instantly. Anyway, although there is a bit o coma at the edges, i have to say the this looks not bad at all, better than an 80mm orion triplet with flattner i once saw. i mean the stars are tiny and yeah it deserves a flattner.

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One APSc shot, almost as shot, TV-101 @ 540mm with no flattner on Losmandy GM8 150s exposure under good old romanian  skies . I thought i could explore what this scope is capable of photographically because i really can t find that much material on it. Right now i m pretty pleased with it even though the stars close to the edge do exhibit a bit of coma (yes that is coma). Actually from what i have heard that is the difference between the TV and the NP. Planning on getting the NPR1073 and will post some more shots here.

Clear skies!

Vlad

post-40857-0-66428100-1421544911_thumb.j

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Again, i am asking, has anyone used and reducers and or flattenrs on this scope? NPR1073 or LCL1069 ? And if so, what were the results?

Have you tried asking this question in the Cloudy Nights forum. TV 101 is a USA made scope which is not widely used in the UK mainly due to the price. CN being a US based forum may have a better chance of having someone using the combination you are asking about?

A.G

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  • 1 month later...

Did you ever get any further with this topacid? 

Was thinking about exploring imaging a bit more next winter (when I hopefully will have some sort of observatory)

Only vaguely suitable camera I have right now is a full-frame Nikon D700 so I'd be very interested in whether your flattener quest worked out. 

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I tried the TV101 for imaging with an aps-c sensor 450d it wasn't good, i sent a sub to tv and they said the issue was that the tv just wasn't an imaging scope.

cracking for visual but alas not imaging.

That was my experience

Ray

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Just to add. I basically asked to speak to someone about the imaging qualities of the scope. Short pause. 'Hi this is Al Nagler, how can I help?'

Got to admire that approach. Got a technical question? Talk to the guy who designed the scope. 

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