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Re: [skyquest-telescopes] EP collection?

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  • Phil Lefever
    ... Hi John, Let me throw out a few thoughts before I mention what I like in my XT10. First of all here are a few helpful articles on the TeleVue web site, you
    Message 1 of 23 , Nov 1, 2007
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      >I am trying to put together a good premium EP spread for my XT10i. I
      >am looking at the TV Nagler line but will be willing to consider
      >Pentax XW EPs for the high power range. I am also willing to consider
      >incorporating a TV powermate into the spread.

      Hi John,

      Let me throw out a few thoughts before I mention what I like
      in my XT10.

      First of all here are a few helpful articles on the TeleVue web
      site, you may have already seen them:

      Choosing Your Telescopes Magnification
      http://www.televue.com/engine/page.asp?ID=140

      Eyepieces for Small Dobs
      http://www.televue.com/engine/page.asp?ID=221

      Next remember that eyepiece selection is HIGHLY personal,
      what I or others like may not make you happy. Find a local
      store or attend a star party and look through some of your
      possible choices if at all possible!

      Now for selecting eyepieces. First off I find it better if you
      don't consider magnification but you consider true Field of
      View (TFoV) and exit pupil size. Only when I am observing
      the Planets do I think of magnification, the rest of the time
      I think of the eyepiece's TFoV and exit pupil. If you have
      an idea of how large an object is then you pick the eyepiece
      that frames it correctly, magnification doesn't really define
      anything useful.

      A usable set of eyepieces will usually give ~ 3 choices. More
      if you have a lot of money but there is really no reason to plug
      all the gaps. If you are really into Planetary observing having a
      few more choices up top may make sense. Here is what I
      suggest:

      #1. The widest TFoV eyepiece. Often used as a "finder" or
      for viewing large deep sky objects. Beware that you don't
      choose an eyepiece that yields an excessively large exit pupil.
      For me I find that an exit pupil 7 mm and larger tends to make
      the background sky look grey and milky, degrading usable
      contrast. Your eye and skies may be different.

      #2. An eyepiece that gives an exit pupil of ~2-3 mm and a
      TFoV of 3/4 to 1 Degree. This will be your most frequently
      used eyepiece for most deep sky observing. It will also be
      usable in a 2x Barlow when seeing allows. I use this choice
      about 75% of the time. Buy this eyepiece first and buy one
      that is top shelf, don't skimp on the primary eyepiece!

      #3. An eyepiece that when used with the Barlow will put the
      scope near its maximum magnification (your minimum
      usable exit pupil). For me this is ~300x for a 10" scope or
      a .8mm exit pupil size. Above this the image quality only
      falls off. Of course your eye is different and some people
      will run much smaller exit pupils.

      So brass tacks time for the 10" f/4.7 XT... And these are
      my OPINIONS

      Low power: The 31mm Nagler is the 1st choice, NOTHING
      else comes close! The 26mm Nagler is not a first choice
      as it really is designed to prevent excessive exit pupil size
      in f/4 scopes. At f/4.7 you are loosing TFoV and eye relief
      and saving very little money. The 35mm Pan is OK if you
      can live with the 7mm exit pupil. The 27mm Pan is a great
      choice due to the reasonable exit pupil but it gives up .6
      degrees of FoV to the 31mm Nagler. Its a nice cost and
      weight savings though.

      Mid Power: Something in the 11-13mm range. To me the
      choice is the 12mm Type 4 Nagler, the extra eye relief is
      just too nice. The 11mm or 13mm Type 6 Naglers are both
      great choices too and smaller/cheaper/lighter. Some people
      will point out the Type 6's are likely going to have better
      optical coatings too. The 12mm Radian is also a great pick
      but you lose ~.2 degrees TFoV to the 12mm Nagler. One
      thing to remember is that the 12mm Type 4 IS a 1-1/4"
      eyepiece, ignore the 2" barrel as it won't allow you to reach
      focus in an XT with the eyepiece seated that low.

      High Power: For me its the 7mm Type 6 Nagler. On most
      nights here in MN I can get away with this magnification
      as our seeing is often marginal. It is a bit high if dropped
      into a 2x Barlow though. The 9mm may be a possible choice
      too, especially if you choose the 2.5x Powermate. Also at
      these high magnification choices the Radian line is a good
      pick, again you will lose some TFoV but you don't need it
      as much for framing objects although it is nice in a Dob
      unless you have an EQ platform!

      As for the Barlow again try before you buy if you can. The
      Powermates are excellent as they don't extend the eye relief
      of the eyepiece which can cause problems with long focal
      length eyepieces. Pick one that has the ratio that you desire.
      I'm not a big fan of 2" Barlows, I really consider them a tool
      for photographers only. They are just too heavy when used
      with big 2" eyepieces creating all kinds of balance problems
      in a Dob. I really can't think of a time I ever wanted to use
      my 27mm Pan in a Barlow... There is no need actually as
      my 12mm Nagler has a .1 degree wider TFoV then a 27mm
      Pan used with a 2x Barlow!

      I only addressed the TeleVue made eyepieces. The Pentax
      models that others have mentioned are also good eyepieces.
      I fplace them a bit behind the TeleVue offerings but as I said
      earlier try them out if you can, you might not feel the same.

      Clear Skies,

      PL

      --------------------------------------------------------------------
      Phil Lefever - Burnsville, MN
      Amateur Radio Callsign - KB0NES EN34jt
      C8-SP XT-10 C102 80WV
    • gksabo
      Bill, Thanks for the info and the tip for Hands On Optics. Gary S.
      Message 2 of 23 , Nov 1, 2007
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        Bill,
        Thanks for the info and the tip for Hands On Optics.
        Gary S.

        --- In skyquest-telescopes@yahoogroups.com, Bill Moore <wrm2nd@...> wrote:
        >
        > Pentax, Hands-on Optics, $169
        >
        > gksabo <gkskis@...> wrote: Bill,
        > I'm curious. What brand is your XW12mm eyepiece?
        > Gary S.
        > Northern California
        >
        > --- In skyquest-telescopes@yahoogroups.com, Bill Moore <wrm2nd@> wrote:
        > >
        > > I have just recently added the XW12, just love it.
        > > I read a review that gave it better overall performance that
        > radian 12 at nearly half the price, so I had to try it.
        > >
        > > Other, more experience observers than myself, who have looked
        > through my scopes almost always ask about the eyepiece.
        > >
        > > I'm just starting out with a 8"coulter and a XT10i, but the
        > "pro's" who have had a peek say I did good getting that eyepiece. So I
        > call it a keeper.
        > >
        > > RapidEye <RapidEye.US@> wrote:
        > > On 10/31/07, jonhundley13 <stolimos@> wrote:
        > > > I would appreciate anyone willing to offer advice in this regard.
        > >
        > > Don't look through a Pentax XW 10mm - you'll not want to use any other
        > > type of EP =-)
        > >
        > > From 14mm down to 5mm in the XW line are top notch: very flat, sharp
        > > to the edges, VERY comfortable to use. The 20mm has some field
        > > curvature and is the weakest EP in the lineup, but it is still very
        > > nice. The 30mm is outstanding, but is a 2" EP and more expensive than
        > > the shorter FL.
        > >
        > > I've never looked through an EP that was more comfortable AND gave
        > > better views and that is in scopes all the way from F/12 refractors
        > > down to F/4.3 lightbucket Dobs.
        > >
        > > <RE>
        > >
        > >
        > >
        > >
        > > __________________________________________________
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        > > Tired of spam? Yahoo! Mail has the best spam protection around
        > > http://mail.yahoo.com
        > >
        > > [Non-text portions of this message have been removed]
        > >
        >
        >
        >
        >
        >
        > __________________________________________________
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        > Tired of spam? Yahoo! Mail has the best spam protection around
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      • RapidEye
        ... That is a typo on the Hands On Optics site - there is no such beast as a Pentax XW 12mm. 10mm and 14mm are as close as they get. That 12mm EP is out of
        Message 3 of 23 , Nov 1, 2007
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          On 10/31/07, Bill Moore <wrm2nd@...> wrote:
          > I have just recently added the XW12, just love it.
          > I read a review that gave it better overall performance that radian 12 at nearly half
          > the price, so I had to try it.

          That is a typo on the Hands On Optics site - there is no such beast as
          a Pentax XW 12mm. 10mm and 14mm are as close as they get.
          That 12mm EP is out of their XF line. (F not W)

          The XF's are smaller than the XW's and have a narrower FOV and
          slightly less Eye Relief. I've never looked through one so I have no
          comment on the quality of the views. According to a couple of
          different sources, they use the same type of glass and coatings on
          both lines so I expect them to be a notch (or two or three) above the
          average Plossl and/or Chinese Widefield clones.

          I'll reiterate what Phil said - get to a star party and try out a
          couple of different designs. Make sure you compare apples to apples -
          similar focal length EP's in scopes about the same speed as yours. A
          $40 EP may look great through a F/12 Mak, but in a F/4.4 Newt
          everything looks like comets! =-)

          The great news is that you do have lots of great choices!

          <RE>
        • Jack Kramer
          From: Bill Moore ... Where can you get a Pentax XW at half the price of a Radian? All the prices I ve seen for the 1.25 format XWs are in
          Message 4 of 23 , Nov 1, 2007
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            From: "Bill Moore" <wrm2nd@...>
            >I have just recently added the XW12, just love it.
            > I read a review that gave it better overall performance that radian 12 at nearly half the price, so I had to try it.

            Where can you get a Pentax XW at half the price of a Radian? All the prices I've seen for the 1.25" format XWs are in the $300+ range.

            Jack Kramer
            Lily Lake, Illinois
            http://www.geocities.com/llranch339@.../AstroSite.html
          • johnwunderlin
            ... Phil, Thank you very much for that writeup- I m going to bookmark that as I m hoping to eventually move to a set of all premiums. John Wunderlin Mineral
            Message 5 of 23 , Nov 1, 2007
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              > Let me throw out a few thoughts before I mention what I like
              > in my XT10.

              Phil,

              Thank you very much for that writeup- I'm going to bookmark that as
              I'm hoping to eventually move to a set of all premiums.

              John Wunderlin
              Mineral Point, WI
              XT10i
            • lhk2g
              Be sure to check the Meade series 5000 uwa. I have one of these - 18mm. It is to notch quality, barely distinguishable from Nagler, and I like the colors
              Message 6 of 23 , Nov 1, 2007
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                Be sure to check the Meade series 5000 uwa. I have one of these -
                18mm. It is to notch quality, barely distinguishable from Nagler, and
                I like the colors better - the Naglers have some brownish tint that I
                dislike.
              • jonhundley13
                ... Thanks for all the responses. Yesterday I added my name to the waiting list for a TV 13mm Ethos(expected in 1/08). In the meantime I will be frequenting
                Message 7 of 23 , Nov 2, 2007
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                  --- In skyquest-telescopes@yahoogroups.com, "jonhundley13"
                  <stolimos@...> wrote:
                  >
                  > Hello,
                  >
                  > I am trying to put together a good premium EP spread for my XT10i. I
                  > am looking at the TV Nagler line but will be willing to consider
                  > Pentax XW EPs for the high power range. I am also willing to consider
                  > incorporating a TV powermate into the spread.
                  >
                  > I would appreciate anyone willing to offer advice in this regard.
                  >
                  > Thanks, John H
                  >

                  Thanks for all the responses.

                  Yesterday I added my name to the waiting list for a TV 13mm
                  Ethos(expected in 1/08). In the meantime I will be frequenting
                  astromart looking for a 31mm nagler, a TV paracorr, and a 2X
                  powermate. I am hoping that the next EP in the Ethos line is a 9mm.

                  John H
                • BMWBOB
                  Nice selection! I have a 12mm Type 4 and with 2X Powermate I m close to the limits of quality seeing. I d like to get the 31mm, but the 35mm Panoptic will do
                  Message 8 of 23 , Nov 2, 2007
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                    Nice selection! I have a 12mm Type 4 and with 2X Powermate I'm close to the limits of quality seeing. I'd like to get the 31mm, but the 35mm Panoptic will do for now and need to save pennies for an ethos!


                    ----- Original Message ----
                    From: jonhundley13 <stolimos@...>
                    To: skyquest-telescopes@yahoogroups.com
                    Sent: Friday, November 2, 2007 10:38:43 AM
                    Subject: [skyquest-telescopes] Re: EP collection?

                    --- In skyquest-telescopes @yahoogroups. com, "jonhundley13"
                    <stolimos@.. .> wrote:
                    >
                    > Hello,
                    >
                    > I am trying to put together a good premium EP spread for my XT10i. I
                    > am looking at the TV Nagler line but will be willing to consider
                    > Pentax XW EPs for the high power range. I am also willing to consider
                    > incorporating a TV powermate into the spread.
                    >
                    > I would appreciate anyone willing to offer advice in this regard.
                    >
                    > Thanks, John H
                    >

                    Thanks for all the responses.

                    Yesterday I added my name to the waiting list for a TV 13mm
                    Ethos(expected in 1/08). In the meantime I will be frequenting
                    astromart looking for a 31mm nagler, a TV paracorr, and a 2X
                    powermate. I am hoping that the next EP in the Ethos line is a 9mm.

                    John H




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                    [Non-text portions of this message have been removed]
                  • Phil Lefever
                    ... John, I see you aren t afraid to pull the trigger ;) I wouldn t consider an Ethos till I look through one. Of course I am very anxious to do so, but I m
                    Message 9 of 23 , Nov 2, 2007
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                      >Yesterday I added my name to the waiting list for a TV 13mm
                      >Ethos(expected in 1/08). In the meantime I will be frequenting
                      >astromart looking for a 31mm nagler, a TV paracorr, and a 2X
                      >powermate. I am hoping that the next EP in the Ethos line is a 9mm.

                      John,

                      I see you aren't afraid to pull the trigger ;)

                      I wouldn't consider an Ethos till I look through one. Of
                      course I am very anxious to do so, but I'm worried that
                      the extra AFoV will just not be useful. In normal use I
                      don't see the edges at 82 degrees... Also after seeing
                      the price I have to admit that I hope I don't like it!

                      Skip the Paracor until you KNOW you have an issue.

                      And reiterating my opinion, forget about the 2" format
                      Barlow too. Its not like you'd really use the 31mm Nagler
                      in it anyhow. $700 & 6.6+ lbs at the nose of an XT10
                      is pretty questionable in my opinion...

                      Clear Skies,

                      PL

                      --------------------------------------------------------------------
                      Phil Lefever - Burnsville, MN
                      Amateur Radio Callsign - KB0NES EN34jt
                      C8-SP XT-10 C102 80WV
                    • Bill Neve
                      Mid Power: Something in the 11-13mm range. To me thechoice is the 12mm Type 4 Nagler, the extra eye relief isjust too nice. The 11mm or 13mm Type 6 Naglers are
                      Message 10 of 23 , Nov 7, 2007
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                        Mid Power: Something in the 11-13mm range. To me thechoice is the 12mm Type 4 Nagler, the extra eye relief isjust too nice. The 11mm or 13mm Type 6 Naglers are bothgreat choices too and smaller/cheaper/lighter. Some peoplewill point out the Type 6's are likely going to have betteroptical coatings too. The 12mm Radian is also a great pickbut you lose ~.2 degrees TFoV to the 12mm Nagler. Onething to remember is that the 12mm Type 4 IS a 1-1/4"eyepiece, ignore the 2" barrel as it won't allow you to reachfocus in an XT with the eyepiece seated that low.
                        Was wondering if you could describe in more detail the differences between the 12mm Type 4 and the 11/13mm Type 6's? I'm wondering what might be worth the extra +/- $60 for the Type 4 over the Type 6's. Have a f/4.7 XT10i, view in moderately light polluted skies, and am looking to get my first quality eyepiece. I wish I had the opportunity to test them out, but am in a fairly remote location ( no local groups) where that is not immediately possible. Sure appreciate all the good adivce and knowledge spread through this forum.

                        Bill










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                      • wlntcn
                        ... Was wondering if you could describe in more detail the differences between the 12mm Type 4 and the 11/13mm Type 6 s? I m wondering what might be worth the
                        Message 11 of 23 , Nov 7, 2007
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                          --- In skyquest-telescopes@yahoogroups.com, Phil Lefever <kb0nes@...>
                          wrote:

                          >
                          > Mid Power: Something in the 11-13mm range. To me the
                          > choice is the 12mm Type 4 Nagler, the extra eye relief is
                          > just too nice. The 11mm or 13mm Type 6 Naglers are both
                          > great choices too and smaller/cheaper/lighter. Some people
                          > will point out the Type 6's are likely going to have better
                          > optical coatings too. The 12mm Radian is also a great pick
                          > but you lose ~.2 degrees TFoV to the 12mm Nagler. One
                          > thing to remember is that the 12mm Type 4 IS a 1-1/4"
                          > eyepiece, ignore the 2" barrel as it won't allow you to reach
                          > focus in an XT with the eyepiece seated that low.


                          Was wondering if you could describe in more detail the differences
                          between the 12mm Type 4 and the 11/13mm Type 6's? I'm wondering what
                          might be worth the extra +/- $60 for the Type 4 over the Type 6's.
                          Have a f/4.7 XT10i, view in moderately light polluted skies, and am
                          looking to get my first quality eyepiece. I wish I had the
                          opportunity to test them out, but am in a fairly remote location ( no
                          local groups) where that is not immediately possible. Sure appreciate
                          all the good adivce and knowledge spread through this forum.

                          Bill
                        • Phil Lefever
                          ... Well the primary difference is the eye relief. Which eyepiece you prefer will depend on what you like in that regard. With the 12mm Nagler Type 4 eye
                          Message 12 of 23 , Nov 10, 2007
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                            >Was wondering if you could describe in more detail the differences
                            >between the 12mm Type 4 and the 11/13mm Type 6's? I'm wondering what
                            >might be worth the extra +/- $60 for the Type 4 over the Type 6's.

                            Well the primary difference is the eye relief. Which eyepiece you
                            prefer will depend on what you like in that regard.

                            With the 12mm Nagler Type 4 eye relief is long, I think its 17mm
                            or thereabouts. I know that with my glasses on I can see the edge
                            of the FoV. Also the Type 4 has an "Instajust" eye guard like on
                            the Radian models that can be raised and lowered to the right
                            place for observing without glasses. In most cases I observe with
                            my glasses off and I have no eye placement issues in that manner
                            either. One often overlooked advantage of long eye relief is that
                            it prevents your eye lashes from soiling the eye lens and in cold
                            weather the lens is less likely to fog too.

                            The Type 6 Naglers have much shorter eye relief, I believe that
                            they state it as being 12mm but to me it seems shorter then that.
                            You can use them with glasses on but you will only see the inner
                            part of the FoV. To see the edges you have to suck the eye cup
                            into your eye socket. Some people don't mind getting in close
                            but others do.

                            Other differences are mostly physical. The Type 6 models are
                            smaller 1-1/4" that were designed to allow use in a binoviewer.
                            The Type 4 is much larger and wouldn't allow use in a binoviewer.
                            It also has a 2" barrel to allow its use in SCT's and refractors
                            mounted as a 2" eyepiece. Note that in most Newtonian scopes
                            with their limited focuser travel it won't reach focus in this manner.
                            This isn't a problem as the 2" barrel is for convenience only and
                            optical performance is the same when mounted either way. If
                            there was anything I'd change it would be to get rid of the silly
                            2" barrel, I just don't see any use for it.

                            Finally its possible (likely?) that the Type 6 is superior optically.
                            The higher type numbers usually use more modern design and
                            often better anti-reflection coatings etc. TeleVue has worked hard
                            over the years to minimize distortions in the Naglers and they
                            seem to get better with each revision. The most noticeable change
                            has been reduction of exit pupil spherical aberration which causes
                            the "kidney" bean blackouts, the early Naglers were worse in this
                            regard then the current crop are. Note that I never really considered
                            this a problem as it really is only troubling in daylight when your
                            eye's pupil is small, out in the dark things are more forgiving. But
                            when I did my comparison I didn't really see any significant optical
                            difference so I picked the more usable one.

                            For me, the eye relief wins hands down, so I paid the extra money
                            for the 12mm Type 4. Now when I went for a high power model I
                            picked the 7mm Type 6, but I wish they made a 7mm Type 4...
                            with the longer eye relief though. I had considered the Meade 8.8mm
                            SWA but I really don't want a Meade eyepiece, with my luck I'd drop
                            it and they don't repair them. I'll stick to a company that offers support
                            after the sale.

                            Clear Skies,

                            PL

                            --------------------------------------------------------------------
                            Phil Lefever - Burnsville, MN
                            Amateur Radio Callsign - KB0NES EN34jt
                            C8-SP XT-10 C102 80WV
                          • John Bambury
                            ... Phil, They do, its called a 7mm Pentax XW. FOV aside it s a better performer than anything Televue make at this focal length, in widefield/ultrawidefield
                            Message 13 of 23 , Nov 12, 2007
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                              --- In skyquest-telescopes@yahoogroups.com, Phil Lefever <kb0nes@...>
                              wrote:
                              >
                              > Now when I went for a high power model I
                              > picked the 7mm Type 6, but I wish they made a 7mm Type 4...
                              > with the longer eye relief though. I had considered the Meade 8.8mm
                              > SWA but I really don't want a Meade eyepiece.
                              >
                              > Clear Skies,
                              >
                              > PL
                              >
                              > --------------------------------------------------------------------
                              > Phil Lefever - Burnsville, MN
                              > Amateur Radio Callsign - KB0NES EN34jt
                              > C8-SP XT-10 C102 80WV
                              >


                              Phil,

                              They do, its called a 7mm Pentax XW. FOV aside it's a better
                              performer than anything Televue make at this focal length, in
                              widefield/ultrawidefield design. Actually, its better than anything
                              any other company make at this focal length in widefield design.
                              While a lot of the differences are very minimal and wouldn't be
                              noticed by a lot of observers, you get superior optical performance
                              combined with the immersion and comfort of a Nagler T4.

                              Cheers,
                              John B
                            • mellingmount
                              Hi I think that sounds like extremely well informed advice, i always thought that an exit pupil at about 7mm max would ensure you are not wasting too much of
                              Message 14 of 23 , Dec 12, 2007
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                                Hi

                                I think that sounds like extremely well informed advice, i always
                                thought that an exit pupil at about 7mm max would ensure you are not
                                wasting too much of the light, but of course a very small exit pupil
                                means you waste none of it, i had never thought of it like that!!
                                doh!

                                i always find i am a little dissapointed with contrast, but i do
                                also want a nice wide field of view, and, with suburban skies and a
                                12 inch F5, could you please reccomend one or two eyepieces i might
                                like.

                                I have hyperions at the moment, 13mm and 8mm, and they are very very
                                nice, but i am always craving for better contrast!!

                                i hope you might have a minute to let me know what you think...

                                clear skies

                                dave



                                --- In skyquest-telescopes@yahoogroups.com, Phil Lefever
                                <kb0nes@...> wrote:
                                >
                                >
                                > >I am trying to put together a good premium EP spread for my
                                XT10i. I
                                > >am looking at the TV Nagler line but will be willing to consider
                                > >Pentax XW EPs for the high power range. I am also willing to
                                consider
                                > >incorporating a TV powermate into the spread.
                                >
                                > Hi John,
                                >
                                > Let me throw out a few thoughts before I mention what I like
                                > in my XT10.
                                >
                                > First of all here are a few helpful articles on the TeleVue web
                                > site, you may have already seen them:
                                >
                                > Choosing Your Telescopes Magnification
                                > http://www.televue.com/engine/page.asp?ID=140
                                >
                                > Eyepieces for Small Dobs
                                > http://www.televue.com/engine/page.asp?ID=221
                                >
                                > Next remember that eyepiece selection is HIGHLY personal,
                                > what I or others like may not make you happy. Find a local
                                > store or attend a star party and look through some of your
                                > possible choices if at all possible!
                                >
                                > Now for selecting eyepieces. First off I find it better if you
                                > don't consider magnification but you consider true Field of
                                > View (TFoV) and exit pupil size. Only when I am observing
                                > the Planets do I think of magnification, the rest of the time
                                > I think of the eyepiece's TFoV and exit pupil. If you have
                                > an idea of how large an object is then you pick the eyepiece
                                > that frames it correctly, magnification doesn't really define
                                > anything useful.
                                >
                                > A usable set of eyepieces will usually give ~ 3 choices. More
                                > if you have a lot of money but there is really no reason to plug
                                > all the gaps. If you are really into Planetary observing having a
                                > few more choices up top may make sense. Here is what I
                                > suggest:
                                >
                                > #1. The widest TFoV eyepiece. Often used as a "finder" or
                                > for viewing large deep sky objects. Beware that you don't
                                > choose an eyepiece that yields an excessively large exit pupil.
                                > For me I find that an exit pupil 7 mm and larger tends to make
                                > the background sky look grey and milky, degrading usable
                                > contrast. Your eye and skies may be different.
                                >
                                > #2. An eyepiece that gives an exit pupil of ~2-3 mm and a
                                > TFoV of 3/4 to 1 Degree. This will be your most frequently
                                > used eyepiece for most deep sky observing. It will also be
                                > usable in a 2x Barlow when seeing allows. I use this choice
                                > about 75% of the time. Buy this eyepiece first and buy one
                                > that is top shelf, don't skimp on the primary eyepiece!
                                >
                                > #3. An eyepiece that when used with the Barlow will put the
                                > scope near its maximum magnification (your minimum
                                > usable exit pupil). For me this is ~300x for a 10" scope or
                                > a .8mm exit pupil size. Above this the image quality only
                                > falls off. Of course your eye is different and some people
                                > will run much smaller exit pupils.
                                >
                                > So brass tacks time for the 10" f/4.7 XT... And these are
                                > my OPINIONS
                                >
                                > Low power: The 31mm Nagler is the 1st choice, NOTHING
                                > else comes close! The 26mm Nagler is not a first choice
                                > as it really is designed to prevent excessive exit pupil size
                                > in f/4 scopes. At f/4.7 you are loosing TFoV and eye relief
                                > and saving very little money. The 35mm Pan is OK if you
                                > can live with the 7mm exit pupil. The 27mm Pan is a great
                                > choice due to the reasonable exit pupil but it gives up .6
                                > degrees of FoV to the 31mm Nagler. Its a nice cost and
                                > weight savings though.
                                >
                                > Mid Power: Something in the 11-13mm range. To me the
                                > choice is the 12mm Type 4 Nagler, the extra eye relief is
                                > just too nice. The 11mm or 13mm Type 6 Naglers are both
                                > great choices too and smaller/cheaper/lighter. Some people
                                > will point out the Type 6's are likely going to have better
                                > optical coatings too. The 12mm Radian is also a great pick
                                > but you lose ~.2 degrees TFoV to the 12mm Nagler. One
                                > thing to remember is that the 12mm Type 4 IS a 1-1/4"
                                > eyepiece, ignore the 2" barrel as it won't allow you to reach
                                > focus in an XT with the eyepiece seated that low.
                                >
                                > High Power: For me its the 7mm Type 6 Nagler. On most
                                > nights here in MN I can get away with this magnification
                                > as our seeing is often marginal. It is a bit high if dropped
                                > into a 2x Barlow though. The 9mm may be a possible choice
                                > too, especially if you choose the 2.5x Powermate. Also at
                                > these high magnification choices the Radian line is a good
                                > pick, again you will lose some TFoV but you don't need it
                                > as much for framing objects although it is nice in a Dob
                                > unless you have an EQ platform!
                                >
                                > As for the Barlow again try before you buy if you can. The
                                > Powermates are excellent as they don't extend the eye relief
                                > of the eyepiece which can cause problems with long focal
                                > length eyepieces. Pick one that has the ratio that you desire.
                                > I'm not a big fan of 2" Barlows, I really consider them a tool
                                > for photographers only. They are just too heavy when used
                                > with big 2" eyepieces creating all kinds of balance problems
                                > in a Dob. I really can't think of a time I ever wanted to use
                                > my 27mm Pan in a Barlow... There is no need actually as
                                > my 12mm Nagler has a .1 degree wider TFoV then a 27mm
                                > Pan used with a 2x Barlow!
                                >
                                > I only addressed the TeleVue made eyepieces. The Pentax
                                > models that others have mentioned are also good eyepieces.
                                > I fplace them a bit behind the TeleVue offerings but as I said
                                > earlier try them out if you can, you might not feel the same.
                                >
                                > Clear Skies,
                                >
                                > PL
                                >
                                > -------------------------------------------------------------------
                                -
                                > Phil Lefever - Burnsville, MN
                                > Amateur Radio Callsign - KB0NES EN34jt
                                > C8-SP XT-10 C102 80WV
                                >
                              • Phil Lefever
                                ... Well you would probably like a 31mm Nagler and a 13mm Ethos ;) The cost is a different story... ... Now while the Hyperions may not have the best
                                Message 15 of 23 , Dec 12, 2007
                                • 0 Attachment
                                  >i always find i am a little dissapointed with contrast, but i do
                                  >also want a nice wide field of view, and, with suburban skies and a
                                  >12 inch F5, could you please reccomend one or two eyepieces i might
                                  >like.

                                  Well you would probably like a 31mm Nagler and a 13mm Ethos ;) The
                                  cost is a different story...

                                  >I have hyperions at the moment, 13mm and 8mm, and they are very very
                                  >nice, but i am always craving for better contrast!!

                                  Now while the Hyperions may not have the best anti-reflection coatings
                                  you are quite unlikely to see much if any significant difference between
                                  their contrast and that of the best eyepieces available. I have a feeling
                                  that you are looking for contrast in all the wrong places. As I recall you
                                  live in a fairly light polluted area and there is no fix for that other then
                                  observing from somewhere else. Spend the cost of the better eyepieces
                                  on some petrol and get to dark skies, you will be much more impressed
                                  with that change!

                                  Clear Skies,

                                  PL

                                  -------------------------------------------------------------------

                                  Phil Lefever - Burnsville, MN
                                  Amateur Radio Callsign - KB0NES EN34jt
                                  C8-SP XT-10 C102 80WV
                                • haggerty.shawn@sfr.fr
                                  Dave: After a year of carefully contemplating all the information I could aquire, and with a few looks in other scopes, here s my dream team ep s that I
                                  Message 16 of 23 , Dec 13, 2007
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                                    Dave: After a year of carefully contemplating all the information I could aquire, and with a few looks in other scopes, here's my "dream team" ep's that I bought for my xt10i f4.7 Dob. I had initially decided that since I was going to pay for premium ep's I was only going to get 3, low, medium, and high power: low: 27mm panoptic 44.5x 1.53° true field 5.7mm exit pupil (price and exit pupil sold me on this one) medium: 12mm Nagler t4 100x .82° true field (I spent months debating between this & the 14 or 10mm Pentax XW, but the TV sale won) high: 7mm Pentax XW 171.5x 41° true field (with the TV sale I could have had the 7mm Nag t6 for about the same price, but I decided on the comfortable 20mm eye relief and what I find as slightly better resolution and contrast in the XW line!) So there it is, what I found was the best for ME and my scope, and don't knock the 27mm Panoptic, it's a great piece of glass, tact sharp as they say and the exit pupil is close to my measured dark site exit pupil, and of coarse a lot cheaper than a 31Nag or a 41Pan or 30 or 40XW. Annnnnddd that damned little devil in my head kept saying TV sale, TV sale, sooo I stopped drinking beer, cut my kid's allowence, didnt say anything to the wife and ordered a 17mm Nagler t4 (looked through one only once, but fell in love). I'm gonna have to get credit for Christmas , but Ive got what I want! Shawn Haggerty Avignon, France ======================================== Message du 12/12/07 21:19 De : "mellingmount" <dave.kelley@...> A : skyquest-telescopes@yahoogroups.com Copie à : Objet : [skyquest-telescopes] Re: EP collection? Hi I think that sounds like extremely well informed advice, i always thought that an exit pupil at about 7mm max would ensure you are not wasting too much of the light, but of course a very small exit pupil means you waste none of it, i had never thought of it like that!! doh! i always find i am a little dissapointed with contrast, but i do also want a nice wide field of view, and, with suburban skies and a 12 inch F5, could you please reccomend one or two eyepieces i might like. I have hyperions at the moment, 13mm and 8mm, and they are very very nice, but i am always craving for better contrast!! i hope you might have a minute to let me know what you think... clear skies dave --- In skyquest-telescopes@yahoogroups.com, Phil Lefever <kb0nes@...> wrote: > > > >I am trying to put together a good premium EP spread for my XT10i. I > >am looking at the TV Nagler line but will be willing to consider > >Pentax XW EPs for the high power range. I am also willing to consider > >incorporating a TV powermate into the spread. > > Hi John, > > Let me throw out a few thoughts before I mention what I like > in my XT10. > > First of all here are a few helpful articles on the TeleVue web > site, you may have already seen them: > > Choosing Your Telescopes Magnification > http://www.televue.com/engine/page.asp?ID=140 > > Eyepieces for Small Dobs > http://www.televue.com/engine/page.asp?ID=221 > > Next remember that eyepiece selection is HIGHLY personal, > what I or others like may not make you happy. Find a local > store or attend a star party and look through some of your > possible choices if at all possible! > > Now for selecting eyepieces. First off I find it better if you > don't consider magnification but you consider true Field of > View (TFoV) and exit pupil size. Only when I am observing > the Planets do I think of magnification, the rest of the time > I think of the eyepiece's TFoV and exit pupil. If you have > an idea of how large an object is then you pick the eyepiece > that frames it correctly, magnification doesn't really define > anything useful. > > A usable set of eyepieces will usually give ~ 3 choices. More > if you have a lot of money but there is really no reason to plug > all the gaps. If you are really into Planetary observing having a > few more choices up top may make sense. Here is what I > suggest: > > #1. The widest TFoV eyepiece. Often used as a "finder" or > for viewing large deep sky objects. Beware that you don't > choose an eyepiece that yields an excessively large exit pupil. > For me I find that an exit pupil 7 mm and larger tends to make > the background sky look grey and milky, degrading usable > contrast. Your eye and skies may be different. > > #2. An eyepiece that gives an exit pupil of ~2-3 mm and a > TFoV of 3/4 to 1 Degree. This will be your most frequently > used eyepiece for most deep sky observing. It will also be > usable in a 2x Barlow when seeing allows. I use this choice > about 75% of the time. Buy this eyepiece first and buy one > that is top shelf, don't skimp on the primary eyepiece! > > #3. An eyepiece that when used with the Barlow will put the > scope near its maximum magnification (your minimum > usable exit pupil). For me this is ~300x for a 10" scope or > a .8mm exit pupil size. Above this the image quality only > falls off. Of course your eye is different and some people > will run much smaller exit pupils. > > So brass tacks time for the 10" f/4.7 XT... And these are > my OPINIONS > > Low power: The 31mm Nagler is the 1st choice, NOTHING > else comes close! The 26mm Nagler is not a first choice > as it really is designed to prevent excessive exit pupil size > in f/4 scopes. At f/4.7 you are loosing TFoV and eye relief > and saving very little money. The 35mm Pan is OK if you > can live with the 7mm exit pupil. The 27mm Pan is a great > choice due to the reasonable exit pupil but it gives up .6 > degrees of FoV to the 31mm Nagler. Its a nice cost and > weight savings though. > > Mid Power: Something in the 11-13mm range. To me the > choice is the 12mm Type 4 Nagler, the extra eye relief is > just too nice. The 11mm or 13mm Type 6 Naglers are both > great choices too and smaller/cheaper/lighter. Some people > will point out the Type 6's are likely going to have better > optical coatings too. The 12mm Radian is also a great pick > but you lose ~.2 degrees TFoV to the 12mm Nagler. One > thing to remember is that the 12mm Type 4 IS a 1-1/4" > eyepiece, ignore the 2" barrel as it won't allow you to reach > focus in an XT with the eyepiece seated that low. > > High Power: For me its the 7mm Type 6 Nagler. On most > nights here in MN I can get away with this magnification > as our seeing is often marginal. It is a bit high if dropped > into a 2x Barlow though. The 9mm may be a possible choice > too, especially if you choose the 2.5x Powermate. Also at > these high magnification choices the Radian line is a good > pick, again you will lose some TFoV but you don't need it > as much for framing objects although it is nice in a Dob > unless you have an EQ platform! > > As for the Barlow again try before you buy if you can. The > Powermates are excellent as they don't extend the eye relief > of the eyepiece which can cause problems with long focal > length eyepieces. Pick one that has the ratio that you desire. > I'm not a big fan of 2" Barlows, I really consider them a tool > for photographers only. They are just too heavy when used > with big 2" eyepieces creating all kinds of balance problems > in a Dob. I really can't think of a time I ever wanted to use > my 27mm Pan in a Barlow... There is no need actually as > my 12mm Nagler has a .1 degree wider TFoV then a 27mm > Pan used with a 2x Barlow! > > I only addressed the TeleVue made eyepieces. The Pentax > models that others have mentioned are also good eyepieces. > I fplace them a bit behind the TeleVue offerings but as I said > earlier try them out if you can, you might not feel the same. > > Clear Skies, > > PL > > ---------------------------------------------------------- - > Phil Lefever - Burnsville, MN > Amateur Radio Callsign - KB0NES EN34jt > C8-SP XT-10 C102 80WV >


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