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RB Focus Carbon Fiber Double-Vane Spider for Newtonian Telescopes
The RB Focus Carbon Fiber Double-Vane Spider is a secondary mirror spider for Newtonian telescopes, made of 3K carbon fiber and stainless steel. Its two 0.5 mm vanes are spaced 10 mm apart. RB Focus says the thinner vanes reduce weight while improving the rigidity and stability of the secondary support, so collimation holds after long use or transport to the field. A 4-point collimation system with Bob's Knobs makes secondary alignment easier.
0.5mm Vanes and 3K Carbon Fiber Construction
RB Focus says the carbon fiber spider is very resistant to temperature changes, which helps collimation and focus stay where you set them as the temperature varies. The vanes are only 0.5 mm wide.
Diffraction Pattern of the 10 mm Spaced Vanes
RB Focus explains that, contrary to what the double vanes suggest, stars do not show doubled spikes: at focus the patterns cancel out into fine, elongated spikes that give stars a subtle, stylized look. RB Focus adds that this pattern can also be used to confirm focus.
4-Point Secondary Adjustment with Included Bob's Knobs
The spider has 4 collimation points, factory-fitted Bob's Knobs and a modified collimation clutch. RB Focus says this makes it much easier to square the focuser and collimate the secondary mirror, aligning it in a few seconds.
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What are the main benefits of upgrading to the RB Focus Carbon Fiber Spider?
RB Focus highlights its rigidity and stability, its resistance to temperature changes (helping collimation and focus hold), the 0.5 mm vanes, and easier collimation with 4 points and Bob's Knobs.
Will the double-vane design of the RB Focus spider create double diffraction spikes?
No. RB Focus says that at focus the patterns from the two vanes cancel out into fine, elongated spikes rather than doubled ones.
How does the 4-point system on the RB Focus spider make collimation easier?
With 4 collimation points, factory-fitted Bob's Knobs and a modified collimation clutch, RB Focus says squaring the focuser and collimating the secondary becomes much easier.
I have a 250mm Sky-Watcher Newtonian. Will the RB Focus spider fit?
There is a 250 mm version, and the package includes four adapter pieces for Sky-Watcher telescopes. RB Focus does not list specific telescope models, so ask us to confirm the fit for your tube.
How does the RB Focus spider behave during a long imaging session with falling temperatures?
RB Focus says the carbon fiber spider is very resistant to temperature changes, so collimation and focus hold as the temperature varies.
Can I use the diffraction pattern from the RB Focus spider to help me focus?
Yes. RB Focus says that because the spikes come together into a fine, clean pattern at focus, the pattern helps confirm the telescope is in focus.
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| Design |
Double-vane spider |
| Materials |
3K carbon fiber, stainless steel, brass and carbon-fiber PLA (FDM printed) |
| Vane width |
0.5 mm |
| Vane spacing |
10 mm |
| Collimation screws |
Bob's Knobs |
| Collimation points |
4 |
| Sizes |
150, 200, 250 and 300 mm |
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RB Focus Carbon Fiber Double Spider
× 1
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Adapter pieces for Sky-Watcher telescopes
× 4
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- RB Focus 2-Year Warranty
