Loading ...
Sorry, an error occurred while loading the content.

4660Re: [William-Optics] Re: Need advice about Vixen/Orion LVW for Megrez 80

Expand Messages
  • yahoogroups
    Aug 1, 2005
    • 0 Attachment
      I really don't follow the thread about LVWs compensating for coma. I
      haven't found this to be the case, but I use mine on Tak refractors.

      If you don't like "blackouts", go for orthos. They seem to be very
      tolerant regarding where you plop your eye. You can always EP project
      with orthos, and they are reasonably priced. Well, maybe not for a TMB
      or Pentax. ;-) My understanding about orthoscopic EPs is that they have
      the minimal amount of glass for a sharp edge to edge image. As you go
      for a wider field, it takes more lenses to correct at the edges. If you
      get the University Optics orthos, you might as well get the better grade
      that they sell. Personally, I haven't noticed the improvement in
      quality, but the latest generation is par focal.



      Paul Carey wrote:
      > Thanks so much, your comments and Gary's are very helpful. I'm glad
      > you mentioned the 19mm pan Jose, it is certainly less expensive than
      > the 22 and I hadn't considered the difficulty of barlowing the 22.
      > The eye relief is more on the 22, but it is really hard to know how
      > much eye relief my wife really needs - or even if eye relief per se
      > is really the issue with the "blackouts" she experiences, when she
      > can only catch brief glimpses of an object. These blackouts have
      > happened even with the Highlight plossl, which has 12mm ER, and she
      > says it has always been a problem for her. But it is never a problem
      > with the monstrous EP on the telescope at our local observatory,
      > which has very very long eye relief and wide fov.
      >
      > We'll definitely see about getting to a star party this Fall and
      > trying all sorts of eyepieces - that's surely the best way to see
      > what works best. But it will probably be tempting in the mean time
      > to order a used ep or two from Astromart.
      >
      > William Carey
      >
      > --- In William-Optics@yahoogroups.com, "Jose Rola" <jose.rola@g...>
      > wrote:
      >
      >>Hi Paul,
      >>
      >>I have a Vixen Lanthanun LV that I enjoy very much in my newton
      >
      > scopes,
      >
      >>but in the Megrez I do not like it a bit.
      >>I believe that the they are made to correct the coma in the newtons
      >
      > and
      >
      >>since the Megrez does not have it it spoils the image.
      >>
      >>I do not own any vixen LVW but already looked through them and i
      >
      > think the
      >
      >>they have the same problem in the Megrez.
      >>
      >>Regarding the 22mm Panoptic, I also do not recomend it because
      >
      > since it is
      >
      >>one of the panoptics that has the 2''/1.25''
      >>barrel, you will have trouble using it with 1.25" barlows.
      >>
      >>I own a 19mm Panoptic that i enjoy very much, and since I have
      >
      > Astigmatism,
      >
      >>I always use glasses to observe and the eye relief is ok for me.
      >
      > The eye
      >
      >>relief of the 19mm panoptic is 13mm and the eye relief of 7 mm
      >
      > ploss that
      >
      >>you own is less than 6mm.
      >>
      >>If you are realy interested in the vixen LVW type of eyepieces (20
      >
      > mm
      >
      >>eyerelief in all the range) maybe you should also consider the TV
      >
      > Radian
      >
      >>eyepieces, since they all have 20 mm eye relief.
      >>
      >>I never had the oportunity to look through a WO eyepiece so I
      >
      > cannot talk
      >
      >>about them, but they all have a big eye relief, and it is a reason
      >
      > why they
      >
      >>are sold as good to afocal astrophotography.
      >>
      >>For high amplification, (moon, planets, globular clusters and
      >
      > planetary
      >
      >>nebula) for me nothing is better than a orthoscopic eyepiece, or if
      >
      > you can
      >
      >>get one, a TMB monocentric, but this are small field eyepices (40º
      >
      > and 30º).
      >
      >>Because at high amplification the exit pupil of the eyepiece is
      >
      > very small
      >
      >>(less than 3mm) people with astigmatism, like me, can take his
      >
      > glasses off
      >
      >>to observe.
      >>
      >>Regarding Naglers, since I use glasses to observe, I never manage
      >
      > to be
      >
      >>close enough to the eyepice to see the whole 82º of the field. I
      >
      > see the
      >
      >>same field that I see on a Panoptic. Which makes my bank account
      >
      > very happy
      >
      >>:)
      >>
      >>But my main advice to you is to look through the eyepiece before
      >
      > you buy it,
      >
      >>go to a Star Party, a astronomy club metting or in last case take
      >
      > the scope
      >
      >>with you to the store and try it in daylight.
      >>
      >>Hope that my mail helped you a bit.
      >>
      >>Regards
      >>Jose Rola
      >>
      >>
      >>
      >>----- Original Message -----
      >>From: "Paul Carey" <wcarey@p...>
      >>To: <William-Optics@yahoogroups.com>
      >>Sent: Thursday, July 28, 2005 6:09 PM
      >>Subject: [William-Optics] Need advice about Vixen/Orion LVW for
      >
      > Megrez 80
      >
      >>
      >>>Hello group, my wife and I are looking to buy our first widefield
      >>>eyepiece for our Megrez 80 SD. The Megrez is really made for
      >>>widefield of course, but our tight budget has forced us to start
      >
      > with
      >
      >>>plossls and a 2.8X Klee barlow. We have been using primarily a
      >
      > 17mm
      >
      >>>Orion Highlight plossl, very bright, sharp and pleasing views but
      >
      > not
      >
      >>>wide. We also have a TV 7mm plossl. My wife and I use the
      >
      > telescope
      >
      >>>primarily in our yard, which is very light-polluted. So far we
      >
      > have
      >
      >>>mostly been viewing the moon, planets and occasionally Orion
      >
      > nebula,
      >
      >>>all with very good results. Light pollution makes most DSOs
      >>>impractical. We almost never use the Megrez for daytime
      >
      > observation.
      >
      >>>A very important factor will be ease of viewing, because my wife
      >>>doesn't have great vision and has had trouble with our current
      >
      > eps.
      >
      >>>So I think eye relief/exit pupil considerations will have to be
      >
      > strong
      >
      >>>factors. Two wide eyepieces that are well-regarded for both eye
      >>>relief and wide views are the panoptics in the larger focal
      >
      > lengths
      >
      >>>and the Vixen LVW, so these have so far been the primary
      >
      > candidates.
      >
      >>>Almost everyone recommends the 22mm pan for these 80mm
      >
      > refractors, but
      >
      >>>it would be at the upper range of our spending limit. I'm also
      >
      > not
      >
      >>>sure whether 22mm would be enough magnification for us to see
      >
      > much in
      >
      >>>our light-polluted viewing situation (but we can barlow, of
      >
      > course).
      >
      >>>The Vixen and Orion LVW's are supposed to be very close to the
      >
      > pans
      >
      >>>optically, and they maintain a constant 20mm of eye relief at
      >
      > lower
      >
      >>>fls, unlike the pans. I'm thinking maybe a 13mm LVW would be a
      >
      > good
      >
      >>>fl for this telescope and our viewing conditions. Anyone have
      >
      > advice
      >
      >>>or experience with these eps? Thank you,
      >>>
      >>>William Carey
      >>>
      >>>
      >>>
      >>>
      >>>
      >>>
      >>>Yahoo! Groups Links
      >>>
      >>>
      >>>
      >>>
      >>>
      >>>
      >
      >
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
      >
      >
    • Show all 7 messages in this topic