Hello to everyone of the Astro-Foren De!
My name is Marco and I am located in Rome (Italy).
I am pleased to have got the possibility to have access to this respected Forum and please excuse me if I can't write in Goethe's language.
I have just purchased a Takahashi TSA102 (I also have an FS102) and I am intersted in knowing some technical features of this scope.
It is claimed, by vendors not by Taka firm, that the strehl ratio reaches a .992, which seems very much, and I got some information from some amateurs that this is quite a theorical ratio, in fact it should be in the range of .98/.99 depending on the instrument.
I'd like to know, if this has been analysed:
- which the real strehl ratio is?
- depending on the above, which can be the wave lenght limit in terms of /lambda of the optics?
- it seems to me the new triplet is quite sharper on planets that the flourite doblet, even though the color rendition is "colder": is this a consequence of a better correction or just is it the difference between ED glass vs CaF2 objective?
- do you consider this a premium apochromat (in its eange of 4" diameter) or is it just a more industrialised (cheaper) solution vs. the flourite doublet?
- how can it be compared to the mythical Zeiss APQ 4" (my dream! One day I'd like to buy it...) Which lambda correction has the APQ?
- and finally (sorry for these many questions) could be the visual observation improved by using the Zeiss AbbeII eyepieces or is it fine to use other premium eypieces such as Takahashi Hi Le or Pentax XW?
In few words, your technical opinion is very wellcome.
Thanks again and I wish you clear skies (in Rome they are cloudy...) Ciao, Marco[/QUOTE]