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Thread: Eye Pieces.

  1. #1
    John Morris's Avatar
    John Morris Guest

    Default Eye Pieces.



    As a newcomer to the hobby I have recently purchased a celstron 114GT.
    It arrived with 2 eye pieces 10mm and 25mm.
    Iam thinking of buying a 4mm would this be alright for this 4.5" telescope?
    Many Thanks,
    John.



  2. #2
    Paul Lawler's Avatar
    Paul Lawler Guest

    Default Eye Pieces.

    "John Morris" <jmbr19882@blueyonder.co.uk> wrote in message
    news:WFaCc.644$T3.284@front-1.news.blueyonder.co.uk...
    telescope?

    No. Too much power.



  3. #3
    Ernest's Avatar
    Ernest Guest

    Default Eye Pieces.

    > As a newcomer to the hobby I have recently purchased a celstron 114GT. It arrived with 2 eye pieces 10mm and 25mm. I am thinking of buying a 4mm would this be alright for this 4.5" telescope?

    It seems, the following set of eyepieces is optimal for your scope:
    6.3 mm, 10 mm, 16 mm, 27 mm, 43 mm. You have 10 and 25, so at first it
    is better for you to get 6.3 and 40-42, then something like 16-17 to
    collect full set.

  4. #4
    Jon Isaacs's Avatar
    Jon Isaacs Guest

    Default Eye Pieces.

    >It seems, the following set of eyepieces is optimal for your scope:

    Exactly why are these optimal? Since the Nextstar 114 GT has a 1.25 inch
    focuser, 40-42 mm will have the same True Field of View as 32mm, for the vast
    majority of situations, the 32 will provide better views than the 40-42mm
    eyepiece. Also a 32mm doubles with a barlow to a 16 which is a nice.

    jon

  5. #5
    Pat O'Connell's Avatar
    Pat O'Connell Guest

    Default Eye Pieces.



    Ernest wrote:

    For a beginner (like I am) with a new 114GT, I'd suggest the Celestron
    eyepiece kit. For about $100 to $130 (I paid $104), you get five Plossl
    eyepieces, a 2X Barlow, an aluminum clad and foam filled case, and seven
    filters to play with.

    The 32 mm eyepiece in my kit is excellent, as are the 15 and 9. The 4 mm
    eyepiece in the kit is not really usable with a 114GT (it's intended for
    wide field scopes like the NexStar 80). I use the 6 mm only rarely. Of
    the two eyepieces (SMAs IIRC) that come with the 114GT, my 25mm is OK,
    but the 10 isn't too hot. I've found the Barlow in the kit to be OK for
    my purposes, but others in the NexStar group (on Yahoo Groups) say there
    are better quality ones out there. I've used the Moon filter more than
    any others, but YMMV.

    Supposedly the Meade eyepiece kit marketed a few months ago has better
    quality Plossl eyepieces than the Celestron one, but I have no
    experience with them.

    --
    Pat O'Connell
    [note munged EMail address]
    Take nothing but pictures, Leave nothing but footprints,
    Kill nothing but vandals...


  6. #6
    Jon Isaacs's Avatar
    Jon Isaacs Guest

    Default Eye Pieces.

    >For a beginner (like I am) with a new 114GT, I'd suggest the Celestron

    Good idea.

    jon

  7. #7
    Brian Tung's Avatar
    Brian Tung Guest

    Default Eye Pieces.

    Jon Isaacs wrote:

    I wonder if he might have read my most recent Astronomical Games, in which
    one of the eyepiece sequences I propose (in conjunction with a Barlow) has
    focal lengths related in the ratio 8 to 5, which is pretty close to what
    he wrote. Of course, I also wrote that it's impractical to follow that
    scheme exactly, for a variety of reasons.

    On the other hand, he might not have read it at all.

    Brian Tung <brian@isi.edu>
    The Astronomy Corner at http://astro.isi.edu/
    Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
    The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
    My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

  8. #8
    Jon Isaacs's Avatar
    Jon Isaacs Guest

    Default Eye Pieces.

    >

    I started to read it, realized I was going to have to think a bit and so I
    marked it unread and haven't gotten back to reading it.

    My own take on eyepiece ratios is that it is like gearing in a car or truck.
    The low gears/magnifications are pretty far apart but as one gets close to the
    limit of engine/road/telescope/seeing, the gears/eyepiece focal lengths ought
    to get closer together. This allows one to play around as one reaches the
    limit and reach some sort of optimal choice.

    I like something like 32 - 22 - 15 - 9 - 7.5 - 6 - 5 with a couple of barlows
    in case I want to be stupid. This is for scopes F4-F7

    jon

  9. #9
    Brian Tung's Avatar
    Brian Tung Guest

    Default Eye Pieces.

    I (Brian Tung) wrote:

    Jon Isaacs wrote:

    Doggone that!


    Pshaw.

    Brian Tung <brian@isi.edu>
    The Astronomy Corner at http://astro.isi.edu/
    Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
    The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
    My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

  10. #10
    Richard's Avatar
    Richard Guest

    Default Eye Pieces.

    "John Morris" <jmbr19882@blueyonder.co.uk> wrote in message news:<WFaCc.644$T3.284@front-1.news.blueyonder.co.uk>...

    A 4mm will provide 250x in your scope. IMO, this is probably at the very
    limit of the power the scope will support, provided the mirror is ok.
    You would be better off getting a barlow which would give you (if it's
    a 2x job) a 12.5mm and a 5mm eyepiece. 200x is still reasonable for
    the scope. You might also consider a 32mm for your scope as this will
    provide the largest FOV in the 1-1/4" focuser at reasonable cost.
    You can buy 24mm eyepieces with fields almost as wide, and more power with
    field is always a better idea, but the cost will be higher than a 32mm Plossl.
    If you intend to use eyepieces shorter than say 7mm, make sure the collimation
    of the scope is bang on. The results are worth it.
    -Rich

 

 
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