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Re: C9.25 vs C8

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  • James T. Bronson
    ... Is the 9.25 a big enough jump that it would be worth while or should I buy a SAFIX for planet viewing with the 8 . I ve got a pretty complete set of
    Message 1 of 12 , May 1, 2004
      --- In sct-user@yahoogroups.com, "jeffleeg8" <jeff120749@n...> wrote:


      Is the 9.25 a big enough jump that it would be worth while or should
      I buy a SAFIX for planet viewing with the 8". I've got a pretty
      complete set of Ultimas and a FR, I don't intend to go to a 2" setup.


      Jeff,

      The general consensus that I've picked up from most of the old heads
      on these SCT forums is that when upgrading your OTA...increase by at
      least 2 inches in aperture to make it worth your while. I've sensed
      this recommendation is less science...and more experience, FWIW...

      The C9.25 OTA appears to be a "niche scope" that was designed mainly
      for improved astrophotography. An excerpt from Celestron reads...

      "...The 9 1/4" was specifically designed for visual infinity
      focus when using 2" eyepieces and has an optimized baffle system to
      benefit astrophotography by minimizing vignetting at the edge of the
      field of view. Its longer primary focal length and lower
      magnification secondary mirror contribute to a flatter field of view
      at the focal plane and helps to further reduce optical aberrations."

      Since it appears you're not really interested in 2" eyepieces and
      your astrophotography is limited, you may be acquiring features that
      you're not really going to use. As you're probably aware, there is
      a difference in weight between the C8 and the C9.25 OTA's...a very
      small improvement in the limiting magnitude...and a slight gain in
      the Rayleigh and Dawes resolution limits. I've listed a link below
      so that you can compare the spec's between the two different sized
      OTA's...

      http://www.celestron.com/prod_pgs/tel/catcrsref.htm

      An interesting consideration, however...is the fact that every owner
      of a C9.25 appears to be extremely satisfied with it...and the tube
      seems to have almost a "cult following". BTW..."none" of the C9.25
      OTA's are FASTAR/HYPERSTAR capable...

      For $400 net cost...that's a pretty "inexpensive upgrade", so it may
      be worth your while...since you can easily spend that much on a new
      dew heater system in the current market...

      Clear Skies...

      James T. Bronson
    • gnowellsct
      Aperture is the best way to improve your eyepiece, but I have to say that a 9.25 on a CG5 is not the road to happiness IMHO. I DID make the C8=9.25 jump and it
      Message 2 of 12 , May 1, 2004
        Aperture is the best way to improve your eyepiece, but I have to say
        that a 9.25 on a CG5 is not the road to happiness IMHO.

        I DID make the C8=9.25 jump and it is a GOOD one. But I also bought
        a good mount (Losmandy G11). My operating theory was that I could
        observe for years with a g11/9.25 combo (which was and is true) but
        also have the potential to upgrade (which I also did, C14, but I
        kept the 9.25).

        My recommendation would be to bank the money and save for a G11/9.25
        combination. You might get as much as $550 for that C8, btw. The
        G11 9.25 combination is one of the most awesome instrumentation
        combinations in amateur astronomy, regardless of aperture.
        Tremendous capabilities and wind and vibration resistance.

        I also like 2" eyepieces but I understand that resource constraints
        are important. I would not VOLUNTARILY swap from a c8/CG5 to a
        C9.25/CG5.

        In fact you might also think about keeping the C8 and upgrading to
        the CI700 mount, purchased used. This mount has its share of
        quality control problems, but on the other hand, there appear to be
        some people out there who get good use out of it. I think the
        Losmandy G11 is probably a better deal, but sometimes those need to
        be worked on and adjusted too. After your finances have absorbed
        the mount upgrade, you could move to a 9.25, and be positioned down
        the road for a c11 or c14. Meantime the C8 on a bigger, better
        mount would begin to demonstrate in your life just how great a good
        mount can be.

        regards
        Greg N

        --- In sct-user@yahoogroups.com, "jeffleeg8" <jeff120749@n...> wrote:
        > Hi All:
        >
        > Due to a fortunate finding, I'm not going to replace my high end
        > printer, and it just so happens that perhapes a change in main
        > scopes might work for me.
        >
        > I've had a C8 for three years now (bought new). I really like my
        8".
        > I use it mainly from my back yard but not as much as my C5, c90,
        or
        > 12 x 60 binoculars. I've got a CG5 (DSCs and drives) with Al's
        legs
        > and brace and I can use very high powers (400x on nights of exc.
        > seeing) with very little wiggle at focus. Plus I've talked to a
        few
        > folks with such a setup and for visual its ok for a 9.25. Assuming
        I
        > could get $500 bucks from my C8, it wold cost about $400 to
        upgrade
        > to a 9.25 on AA.
        >
        > The only imaging I do is with a Nikon 4500 and digiT setup.
        Probably
        > my favorite vsual targets are globulars.
        >
        > Is the 9.25 a big enough jump that it would be worth while or
        should
        > I buy a SAFIX for planet viewing with the 8". I've got a pretty
        > complete set of Ultimas and a FR, I don't intend to go to a 2"
        setup.
        >
        >
        >
        > Regards,
        >
        > Jeff Lee
      • azzz1588@aol.com
        In a message dated 5/1/2004 9:35:24 AM Eastern Daylight Time, tim71pos@hotmail.com writes: Meantime the C8 on a bigger, better mount would begin to demonstrate
        Message 3 of 12 , May 1, 2004
          In a message dated 5/1/2004 9:35:24 AM Eastern Daylight Time,
          tim71pos@... writes:
          Meantime the C8 on a bigger, better
          mount would begin to demonstrate in your life just how great a good
          mount can be.


          You mean like this ??

          Please title this page. (Page 1)


          There is nothing more stable than a C 8 on a G 11 !

          You can rap on the tripod legs, and no vibration at 200X !!
          Wind ??? I shot a Linar Eclipse (Jan 21 2000) at 13 F
          temps, and 10 - 20 mph wind. Though partially sheltered,
          the wind at it's strongest gusts, was able to move the C 8 OTA
          Still, I just waited them out, and got very good pics.
          G 11, with C 8, and Orion ST 80 on top, I was able to go
          through 52 DSO's in a Messier Marathon till clouds wiped
          me out right before 2 am Was able to use the manual setting
          circles to find every object, and went through the Virgo cluster
          with ease. The G 11 handled both scopes very well !


          I've since gone to a C 11, which really means that it will be a
          longer while before I ever go to a C 14.....




          Allan Mayer


          [Non-text portions of this message have been removed]
        • azzz1588@aol.com
          In a message dated 5/1/2004 10:00:30 AM Eastern Daylight Time, azzz1588@aol.com writes: You mean like this ?? Please title this page. (Page 1) I meant ;
          Message 4 of 12 , May 1, 2004
            In a message dated 5/1/2004 10:00:30 AM Eastern Daylight Time,
            azzz1588@... writes:
            You mean like this ??

            Please title this page. (Page 1)

            I meant ;


            http://members.aol.com/c8g11/c8ong11.html



            Ok, better now..............





            Allan Mayer


            [Non-text portions of this message have been removed]
          • RMOLLISE@aol.com
            In a message dated 5/1/04 9:00:23 AM Central Daylight Time, azzz1588@aol.com writes: There is nothing more stable than a C 8 on a G 11 ! Hi: Sure there is...a
            Message 5 of 12 , May 1, 2004
              In a message dated 5/1/04 9:00:23 AM Central Daylight Time, azzz1588@...
              writes:

              There is nothing more stable than a C 8 on a G 11 !

              Hi:

              Sure there is...a C8 on a Losmandy Titan...but that _may_ be overkill. ;-)

              Peace,
              Rod Mollise
              Author of _Choosing and Using a Schmidt Cassegrain Telescope_
              Like CATs? Try SCT User, the Yahoo Group for CAT Fanciers!
              http://members.aol.com/RMOLLISE/index.html


              [Non-text portions of this message have been removed]
            • Joline and Alvin S.
              I have both scopes and the difference in brightness is not that much, also the OTA is a bit heavier.What mount are you using?I have all the Celestron scts and
              Message 6 of 12 , May 2, 2004
                I have both scopes and the difference in brightness is not that much, also
                the OTA is a bit heavier.What mount are you using?I have all the Celestron
                scts and recently I had a side by side comparison with a C8,C9.25 and a
                C11( Using members of a local astronomy observing group as judges)And as
                expected , as aperature increased resolution and brightness increased with
                the C8 AND C9.25 fairly close and a larger difference with the C11.Based on
                this test either stay with the 8 or get an 11.





                From: "James T. Bronson" <jamesbronson@...>
                To: <sct-user@yahoogroups.com>
                Sent: Saturday, May 01, 2004 5:30 AM
                Subject: [sct-user] Re: C9.25 vs C8


                > --- In sct-user@yahoogroups.com, "jeffleeg8" <jeff120749@n...> wrote:
                >
                >
                > Is the 9.25 a big enough jump that it would be worth while or should
                > I buy a SAFIX for planet viewing with the 8". I've got a pretty
                > complete set of Ultimas and a FR, I don't intend to go to a 2" setup.
                >
                >
                > Jeff,
                >
                > The general consensus that I've picked up from most of the old heads
                > on these SCT forums is that when upgrading your OTA...increase by at
                > least 2 inches in aperture to make it worth your while. I've sensed
                > this recommendation is less science...and more experience, FWIW...
                >
                > The C9.25 OTA appears to be a "niche scope" that was designed mainly
                > for improved astrophotography. An excerpt from Celestron reads...
                >
                > "...The 9 1/4" was specifically designed for visual infinity
                > focus when using 2" eyepieces and has an optimized baffle system to
                > benefit astrophotography by minimizing vignetting at the edge of the
                > field of view. Its longer primary focal length and lower
                > magnification secondary mirror contribute to a flatter field of view
                > at the focal plane and helps to further reduce optical aberrations."
                >
                > Since it appears you're not really interested in 2" eyepieces and
                > your astrophotography is limited, you may be acquiring features that
                > you're not really going to use. As you're probably aware, there is
                > a difference in weight between the C8 and the C9.25 OTA's...a very
                > small improvement in the limiting magnitude...and a slight gain in
                > the Rayleigh and Dawes resolution limits. I've listed a link below
                > so that you can compare the spec's between the two different sized
                > OTA's...
                >
                > http://www.celestron.com/prod_pgs/tel/catcrsref.htm
                >
                > An interesting consideration, however...is the fact that every owner
                > of a C9.25 appears to be extremely satisfied with it...and the tube
                > seems to have almost a "cult following". BTW..."none" of the C9.25
                > OTA's are FASTAR/HYPERSTAR capable...
                >
                > For $400 net cost...that's a pretty "inexpensive upgrade", so it may
                > be worth your while...since you can easily spend that much on a new
                > dew heater system in the current market...
                >
                > Clear Skies...
                >
                > James T. Bronson
                >
                >
                >
                >
                >
                > Visit the sct-user home page at:
                >
                >
                >
                > http://members.aol.com/RMOLLISE/index4.html
                > Yahoo! Groups Links
                >
                >
                >
                >
                >
                > ---
                > [This E-mail scanned for viruses by ezaccess.net]
                >
                >

                ---
                [This E-mail scanned for viruses by ezaccess.net]
              • David
                ... Allan, That chair seat looks -real- familar! It appears to be identical to mine (an office chair with back removed). Mine goes down to about 16 with
                Message 7 of 12 , May 2, 2004
                  --- In sct-user@yahoogroups.com, azzz1588@a... wrote:
                  > http://members.aol.com/c8g11/c8ong11.html

                  Allan,
                  That chair seat looks -real- familar! It appears
                  to be identical to mine (an office chair with back
                  removed). Mine goes down to about 16" with little
                  air cylinder lever thingy. For me, it's the cat's
                  meow when it comes to observing chairs.. and it
                  didn't cost anything (one person's junk is another
                  person's, well, uh, astro chair!)
                  David
                • gnowellsct
                  The 9.25 is worthwhile (from a c8) but obviously if one can afford it the 11 is better. HOWEVER, the big jump from the 8 to either aperture is in the price of
                  Message 8 of 12 , May 3, 2004
                    The 9.25 is worthwhile (from a c8) but obviously if one can afford
                    it the 11 is better. HOWEVER, the big jump from the 8 to either
                    aperture is in the price of the mount that goes with it. The
                    9.25/G11 (or equivalent) is one way to keep the OTA cost down. But
                    at least once you HAVE a mount like the G11 you can consider the
                    jump to 11" or--why not!--the C14.

                    I personally think that a 33% jump in aperture is noticeable, what
                    you get from c8 to c9.25, but one of my "observing passtimes" is at-
                    the-limit detection of faint stars.

                    On the other hand, we have to remember, folks, the jump from an
                    unaided eye to a four inch scope is the most you're ever going to
                    see. Everything else is decreasing marginal returns. To get an
                    equivalent jump from four inches, you'd have to go to an eighty inch
                    primary scope.

                    My Newt rehab project has taught me just what four inches can and
                    cannot do. My 1965 mirror, which I thought was terrific, turned out
                    to be astigmatic on the order of 3/4 wave. Awful. The 1977 mirror
                    I purchased to replace it is terrific and has an excellent star
                    test. I reported here the details I get on Jupiter with it. In any
                    case even the C14 or my friend's Obsessions 15 doesn't go "as far
                    past" the 4 inch as the 4 inch does the unaided eye! They
                    definitely do better.

                    I did a shoot out (said it here many times) several years ago
                    between a c8 (my c8) and a c11 on some objects culled from an
                    observing list and the c8 detected 18 of the 21 or so objecs we
                    viewed, which were run-of-the-mill NGCs, not spectacular Messiers.

                    So it is wise to remember that there is a lifetime of observing to
                    be done at 8 or 9.25 inches (though I'm not contemplating downsizing
                    any time soon), that 9.25 will outperform 8, and, in my view, that
                    the 8" is, in terms of the mount that will carry it, "the biggest of
                    the smaller size scopes", and that the 9.25 is the smallest of the
                    medium size (through 14") scopes, and doesn't belong on a CG5 or
                    even a Vixen GP (GP-DX will work though). Thus the real issue
                    underlying the question of whether to make the jump is whether one
                    has the funds to do something about the mount.

                    regards
                    Greg N




                    --- In sct-user@yahoogroups.com, "Joline and Alvin S."
                    <twinkle@e...> wrote:
                    > I have both scopes and the difference in brightness is not that
                    much, also
                    > the OTA is a bit heavier.What mount are you using?I have all the
                    Celestron
                    > scts and recently I had a side by side comparison with a C8,C9.25
                    and a
                    > C11( Using members of a local astronomy observing group as judges)
                    And as
                    > expected , as aperature increased resolution and brightness
                    increased with
                    > the C8 AND C9.25 fairly close and a larger difference with the
                    C11.Based on
                    > this test either stay with the 8 or get an 11.
                    >
                  • David
                    ... [snip] ... Jeff, I totally agree with Greg, but want to point out another mount option that hasn t been mentioned in this thread. I purchased an EQ6 for my
                    Message 9 of 12 , May 3, 2004
                      --- In sct-user@yahoogroups.com, "gnowellsct" wrote:
                      [snip]
                      > Thus the real issue underlying the question of whether
                      > to make the jump is whether one has the funds to do
                      > something about the mount.
                      >
                      > regards
                      > Greg N

                      Jeff,
                      I totally agree with Greg, but want to point out another
                      mount option that hasn't been mentioned in this thread.

                      I purchased an EQ6 for my C9.25. This mount is similar in
                      weight and capacity to a G-11. Out of the box, it's not
                      suitable for astrophotography (PE is high, and PE curve
                      is irregular), but it's incredibly solid mount for visual
                      use. Like the G-11, it can easily handle a C11 + options
                      if you should later decide to upgrade. You can get the
                      EQ6 from Efston Science (Toronto) for about $700 USD
                      (Orion Atlas is the same mount and sells for $800).

                      For those who are mechanically inclined, a number of tweaks and
                      aftermarket bearings, gears, motors, and drive controllers have been
                      adapted to the EQ6/Atlas. The EQ6 group is filled with reports of
                      various degrees of rebuilds and upgrades. Some have documented
                      performance on upgraded EQ6's that exceeds the G-11 at far less
                      cost... that is, assuming you're inclined to ignore your sweat
                      equity ;-)

                      David Butler
                      EQ6 Moderator
                    • gnowellsct
                      Interesting news about the EQ6. People should be aware that Losmandy has, in the past year or so, adopted new high precision worms which reduce PEC much lower
                      Message 10 of 12 , May 3, 2004
                        Interesting news about the EQ6. People should be aware that
                        Losmandy has, in the past year or so, adopted new high precision
                        worms which reduce PEC much lower than the previous decade's worth
                        of G11s. These worms are available for $25 as a do it yourself
                        upgrade and are the new "default" on G11s. People buying older G11s
                        who want to do imaging should try to find out if they have the "new
                        worms." I bring it up because when we say that the EQ6 "exceeds"
                        the G11 it could mean "the up until last year G11s" or the new
                        G11s. Exceeding an old G11 with a modified EQ 6 might not be hard,
                        exceeding a new one is probably a different story, but I'll leave
                        that to the imagers to discuss, insofar as they're the ones with the
                        PEC measurements.

                        regards Greg N

                        --- In sct-user@yahoogroups.com, "David" <Ginahoy@a...> wrote:
                        > --- In sct-user@yahoogroups.com, "gnowellsct" wrote:
                        > [snip]

                        > For those who are mechanically inclined, a number of tweaks and
                        > aftermarket bearings, gears, motors, and drive controllers have
                        been
                        > adapted to the EQ6/Atlas. The EQ6 group is filled with reports of
                        > various degrees of rebuilds and upgrades. Some have documented
                        > performance on upgraded EQ6's that exceeds the G-11 at far less
                        > cost... that is, assuming you're inclined to ignore your sweat
                        > equity ;-)
                        >
                        > David Butler
                        > EQ6 Moderator
                      • David
                        ... as will I David
                        Message 11 of 12 , May 3, 2004
                          --- In sct-user@yahoogroups.com, "gnowellsct" wrote:
                          ...
                          > Exceeding an old G11 with a modified EQ 6 might not
                          > be hard, exceeding a new one is probably a different
                          > story, but I'll leave that to the imagers to discuss,
                          > insofar as they're the ones with the PEC measurements.
                          >
                          > regards Greg N

                          as will I
                          David
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