72067Re: [ccd-newastro] Re: off-axis guider and filter wheel
- Dec 1, 2012Thanks a lot Robert. That's quite a devastating review, but very helpful.
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
> 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.
> --- In firstname.lastname@example.org, Mark Striebeck <mark.striebeck@...>
> > 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
> > 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<
> > You can also move it freely around - though with 35mm it's rather thick.
> > would have that much space in my light path, but I wouldn't be able to
> > 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"
> > wheels only support 5 positions. How much of a restriction is that? FLI
> > 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]
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