Short review of Svbony Helical focuses.

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Greenman Great Britain
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Short review of Svbony Helical focuses.

#1

Post by Greenman »


I should firstly let's deal with the plural; someone doesn't pay enough attention when ordering from Amazon. A focuser with a Female adapter for SCT was neefed for an SE6 and this is exactly what I ordered, (merely two hours after I ordered the male one). D’oh!

But I think positive, this means I can compare them and the QC/reproducibility. Then I will duly return one,

Interestingly neither of the focuses started exactly at the low zero points, but both stopped precisely at the high zero. The focuser is 43mm long with a 10mm adjustment.

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As shown one was 0.3mm past the low zero, and one was 0.45mm beyond. These numbers were to continue to have an effect; as when you reversed the direction of movement the ’play’ before movement was noticed was identical. In addition, the one with the most play also was noticeably stiffer when returned to a clockwise motion from counter-clockwise.

To be fair both were smooth in motion, and I’m sure the stiffness felt on one would relax with use. I then screwed down the offset screw to see if the rotation locked, it did, but the screw needs tightening hard to secure the barrel (otherwise the ’play’ was again evident).

As a practical test, I focused on the brickwork of the house next door (our weather was dire this weekend). I noted the reading, and then rotated the ring fully in one direction and then back (twice over). After this I focused the brickwork without reference to the scale. Both were spot on in the repeatability of the reading when focus was achieved. I found this a bit surprising; so I repeated the process reversing the direction of the rotation (high to low rather that low to high). I got the same result; it seems that the play is cancelled out whichever way you turn the ring. Good result.

Note on the adapters; both types capitively screw on at both ends, the effect of this is that the scale finishes up wherever the two threads tighten, it would be nice if there was a retainer with a free ring. To be fair this is a cost-saving I understand, given that the units are under £30. Be sure to tighten the adapter thread hard onto the focuser body, otherwise the rotation of the ring can undo the adapter.

The 0.05 precision quoted simply means that the ring is etched every half 0.1mm. This is specification fodder 0.1 etched marks would be fine, as most helical focusers have.

For the cost the focser works just fine, and is secure enough to hold a camera behind it. I'm pleased with them and for my use they are fine.

Again withthe plural; well it just so happens that the male SCT adapter fits nicely into the end of my 102 refractor and the retaining screws hold it securely in place. There will be no returns to Amazon, (I knew my mistake was in fact a plan).

I would recommend the focuser, given the cost/performance ratio.
Cheers,

Tony.

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Smart Scope: Dwarf II - Club and outreach work.

AP Refractor: Altair 72EDF Deluxe F6;1x & 0.8 Flatteners; Antares Versascope 60mm finder. ASIAir Pro.Li battery pack for grab & go.

Celestron AVX Mount; X-cel LX eyepieces & Barlows 2x 3x, ZWO 2” Filter holder,

Cameras: main DSO ASI533MC; DSO guide ASI120MM; Planetary ASI224MC; DSLR Canon EOS100 stock.

Filters: Astronomik IR cut; Optolong L-Pro; Optolong L-Enhance.

Binoculars: Celestron 15 x 70.

Latitude: 52.219853
Longitude: -1.034471
Accuracy: 5 m
Bortle 4 site. https://maps.google.com/?q=52.21985,-1.03447

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Lady Fraktor Slovakia
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Re: Short review of Svbony Helical focuses.

#2

Post by Lady Fraktor »


Very good Tony, glad to hear they will work for you :)
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
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