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class="prefix prefixSilver">Discussion Focuser/Eyepiece

Discussion in 'Eyepieces, Barlows, and Filters' started by ObiWan, May 16, 2020.

Focuser/Eyepiece

Started by ObiWan on May 16, 2020 at 9:00 AM

3 Replies 1385 Views 0 Likes

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  1. ObiWan

    ObiWan New Member

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    I have a Tasco 900/140 reflector telescope. My wife threw out the eyepieces so now I'm looking to replace them. The diameter is 0.965" which limits my choices. I know the telescope is not great. My choices seem to be a 0.965" Plossl (few choices), a 0.965" to 1.25" adapter, or replacing the focuser with a 1.25" one. Advice???
     
  2. Gabby76

    Gabby76 Well-Known Member

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    A very late answer unfortunately but if others are looking for these 0.965"/ 24.5 mm:

    Antares makes a set of Plossl eyepieces of decent quality and not overpriced. (www.antares.space)
    Siebert Optics also makes very good eyepieces in this size, custom sizes may be available as well. (www.siebertoptics.com)
    If in EU, Astro Telescope Company makes very good eyepieces as well along with custom sizes. (www.atc-astro.eu)

    To the focuser question:
    If you can find one with a similar racked in/ out height then it should not be a problem installing a 1.25" focuser. Be aware that you may have to trim the drawtube length to size and the secondary mirror may be slightly undersized though in some situations this can be a advantage.
     
  3. sojourneyer

    sojourneyer Well-Known Member

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    Gabby76 likes this.
  4. Gabby76

    Gabby76 Well-Known Member

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    Adapters do work well and can help in some instances.
    The problem with them is that you are restricted with eyepiece choices.
    Using a 1.25" 50° Plossl you are limited to 24 mm focal length before the view is vignetted, at 60° you are limited to 22 mm, at 68° you are at 20 mm etc.
    You end up losing the ability to use lower powers quickly.

    One other alternative with these telescopes with 0.965" focusers if you want to retain originality is to use 23 mm microscope eyepieces (.92") these are plentiful on the various second hand sites.
    A bit of thin cello tape and they fit into a 0.965" perfectly.
     
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