Apo or Achromat.refractor for visual WL.

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Pluton
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Apo or Achromat.refractor for visual WL.

Post by Pluton »

Hello,
For a white light observation with a solar Wedge, is best an Apo or ED lens refractor,or an achromatic refractor ? the focal lenght is indiferent? best more aperture, for example a 120mm F/8 achro. refractor that an 80ED F/7.5 or F/6 ? the CA is not intrusive in the achro refractor with the solar wedge ? all questions is for visual observations
thank you in advance for your opinion and experience
pluton


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Re: Apo or Achromat.refractor for visual WL.

Post by Merlin66 »

Pluton,
On the assumption you are also using a Continuum (or OIII filter) with the wedge - there's no need for an APO.
I use both the ED80 and the TS102 f11 with no issues.


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Re: Apo or Achromat.refractor for visual WL.

Post by Valery »

For solar works it is MUCH better to have a larger achromat than a smaller APO! You will much more per $.

Or better to spend the difference in the cost between APO and Achro (the same size) for a better filter, say, for a
good Quark or even better filter.

APO is for planetary observing (visual) and deep sky imaging (wide to middle field).

Valery


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Pluton
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Re: Apo or Achromat.refractor for visual WL.

Post by Pluton »

Hello,
Thank you for your response.
But dont´like the visual image with the Continuum filter, only with the polarizer(plus a ND3 filter) filter, there is too much CA with the Achro refractor?
For example, an Achro Celestron Omni 120mm F/8 can be a good alternative to a ED80 refractor for visual observations?
I did, these have more resolution, but,,,, it have CA bothered me ?
I think that a ED or APO refractor have more contrast in the image...but, I like looking solar granulation...., 80mm is sufficient for this ??
Thanks again for tour advice.
Pluton


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Re: Apo or Achromat.refractor for visual WL.

Post by krakatoa1883 »

In spite of the residual CA the 120mm achro will be much better than the smaller 80 APO for WL. I have a 150mm achro and a 90mm apochromat, both are fine and show lot of details however the achro wins in resolving fine structures in granulation and penumbrae.

Based on my experience, for a 120mm f/8.3 filtering the CA is not strictly necessary in observing the Sun in WL. Surely there is no need of a heavy filter as the Baader Continuum (unless you want to do some imaging), visually a light yellow W8 or a Baader Fringe Killer will work fine as well.


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Pluton
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Re: Apo or Achromat.refractor for visual WL.

Post by Pluton »

Thank you very much for your response.
Pluton


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