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

72067Re: [ccd-newastro] Re: off-axis guider and filter wheel

Expand Messages
  • Mark Striebeck
    Dec 1, 2012
    • 0 Attachment
      Thanks a lot Robert. That's quite a devastating review, but very helpful.

      MarkS


      On Sat, Dec 1, 2012 at 12:16 AM, brown_rb <brown_rb@...> wrote:

      > **
      >
      >
      > I have had experience with the TS-OAG.
      > Its true that it takes up 9mm.
      >
      > I have nothing against TS-optics and I have bought many many items from
      > them. They do make some great stuff but there are major issues with the
      > TS-OAG.
      >
      > Eventually after raising the following issues the dealer/manufacturer
      > agreed to take it back.Inherently the design is in my opinion flawed for
      > the following reasons.
      >
      > The screws holding the main adapters in place are small, thin and very
      > fiddly. This means it is very difficult to get it rock solid, and hence it
      > is prone to flexing, as was apparent in subs over time.
      >
      > Next, the main imaging adapter only has three positions that you can
      > position it on, these three positions are spaced 120 degrees apart and
      > fixed, hence one has often needs to rotate the entire adapter to frame the
      > object correctly. If used with a Canon camera, there is only position as
      > the screws used to tighten the adapter plate block mounting the camera in 2
      > of the three positions.
      >
      > Next, the pickoff prism only rotates a small amount, when combined with
      > the above, framing the object and selecting a guide star is much more
      > difficult than the orion or celestron off-axis guiders (which I also happen
      > to have and use).
      >
      > The off-axis adapter is not strong enough to hold an imaging train with
      > filter wheel etc. Its too hard to get it tight enough and hence you will
      > notice flexure over time depending on the OTA position.
      >
      > Cheers
      > Robert
      >
      >
      > --- In ccd-newastro@yahoogroups.com, Mark Striebeck <mark.striebeck@...>
      > wrote:
      > >
      > > Hi,
      > >
      > > I want to get the starlight xpress h694 monochrome camera. With that, I
      > > will need a filter wheel and I also wanted to get an off-axis guider.
      > >
      > > My initial inclination was to get the USB filter
      > > wheel<http://www.sxccd.com/sx-usb-filter-wheel>from starlight xpress
      >
      > > and the off-axis guider for it. I liked the idea to
      > > have everything from one company to avoid adapters and such.
      > >
      > > But then I researched more and came across 2 interesting off-axis
      > guiders:
      > >
      > > 1. TS OAG <http://www.optcorp.com/product.aspx?pid=17671>
      >
      > > I like that you can move it around to find a better guide star, and that
      > > you can focus it independently of the camera. Plus with 9mm it's even
      > > smaller then the SX OAG (which has 13mm)
      > >
      > > 2. TS combined flip mirror and off axis
      > > guider<
      > http://www.optcorp.com/product.aspx?pid=17675&kw=flip%20mirror&st=2>
      >
      > > You can also move it freely around - though with 35mm it's rather thick.
      > I
      > > would have that much space in my light path, but I wouldn't be able to
      > put
      > > everything else into it.
      > >
      > > What's interesting about the latter one is that it would allow me to do
      > > alignment without disassembling everything. I have to setup my scope from
      > > scratch every time, i.e. I have to do the whole alignment procedure every
      > > time.
      > >
      > > With regards to the filter wheel, I need to use 2" filters. Most 2"
      > filter
      > > wheels only support 5 positions. How much of a restriction is that? FLI
      > has
      > > a 7 position filter wheel for 2" filters (FLI
      > > CFW-2-7<http://www.optcorp.com/product.aspx?pid=4241>)
      >
      > > but it weighs 2.9 lbs - that sounds rather heavy.
      > >
      > > Does anybody have experience with these? Or any other ideas?
      > >
      > > Any feedback is welcome - I'm nervous spending this much $$$!
      > >
      > > Thanks
      > > MarkS
      > >
      > >
      > > [Non-text portions of this message have been removed]
      > >
      >
      >
      >


      [Non-text portions of this message have been removed]
    • Show all 3 messages in this topic