SVBony SV106 60mm Guide Scope — image 1
SVBony

SVBony SV106 60mm Guide Scope

60 mm f/4 achromatic guide scope · 240 mm focal length · F9177B

The largest guide scope in the range, for the rigs that need it: long Schmidt-Cassegrains and big Newtonians, where a mini guider simply cannot see the drift that the main camera is recording.

85/ 100
Polaris Score
The one for long focal length SCTs and large Newtonians
From$114.29
Where to buy
Affiliate link — we earn a commission, you pay the same. We rank on fit, not payout.
What problem does this solve?

At 2000 mm, your main camera sees errors your guider cannot.

Guiding is a measurement problem before it is a mechanical one. Your main camera on a 2000 mm Schmidt-Cassegrain resolves detail at well under an arcsecond per pixel. If your guide scope is only sampling at five or six arcseconds per pixel, it is being asked to detect a wobble far smaller than one of its own pixels. Software is clever about this and can find a star's centre to roughly a tenth of a pixel, but the margin narrows until seeing and noise start to look like drift.

Two hundred and forty millimetres of focal length brings guide sampling to roughly two and a half to three arcseconds per pixel, which restores the margin. The 60 mm objective also reaches noticeably deeper, so a long focal length rig imaging a sparse field still has a bright guide star to lock onto. This is the specialist end of the ladder, and on a 500 mm refractor it is entirely the wrong purchase.

You need one if
You need this size if you image at 1500 mm or beyond, on an SCT or a large Newtonian, and your guiding graph has never quite settled.
You can skip it if
Skip it for any imaging scope under about 1200 mm, where a 50 mm guides identically for less money and less weight, and skip it entirely on a mount near its payload limit.
How it actually works

What the setup looks like.

Like every guide scope here it is a passive tube. The system comes together with a camera and software:

Like every guide scope here it is a passive tube. The system comes together with a camera and software:

1
Bolt the rings and rail down
Tube rings and a dovetail rail are included. On a long scope, mount it to the main dovetail or a saddle rather than a finder shoe. At this size a finder shoe is not enough support.
2
Thread a guide camera into the back
The rear takes a 1.25 inch guide camera directly. On a long rig, pair it with a small pixel camera to get the most out of the extra focal length.
3
Focus with the helical barrel
Eight millimetres of helical travel. Set tight stars once and lock the thumbscrew.
4
Let the software close the loop
PHD2, N.I.N.A. or an ASIAIR measures drift several times a minute and corrects the mount before it reaches the exposure.

On very long Schmidt-Cassegrains, consider whether an off-axis guider would serve you better. A separate tube of any size cannot detect the main scope's own mirror flop, and this is the focal length range where mirror flop starts to dominate.

01Will it fit my setup

Compatibility.

What this accessory works with — check the fit before you check the price.

What this accessory works with — check the fit before you check the price.

Long focal length SCTs, Maksutovs and large NewtoniansZWO, QHY, Player One and SVBony guide cameras1.25 inch camera connectionPHD2, N.I.N.A., ASIAIR and EkosMain scopes from roughly 1200 mm to 2500 mm focal length
Note✕Needs a guide camera, sold separately✕270 mm long and the heaviest guider here, so it eats mount payload✕Achromatic doublet, so it guides well and photographs badly✕Cannot see mirror flop in an SCT, which an off-axis guider can✕Overkill and dead weight on a short refractor
02The numbers

What These Numbers Mean

5 numbers in plain English · full specifications

5 numbers in plain English · full specifications

Focal lengthLong
240 mm
This is the whole reason the tube exists. With a 2.9 to 3.75 micron guide camera, 240 mm samples at roughly two and a half to three and a half arcseconds per pixel, about twice as finely as a 30 mm mini guider. On a 2000 mm main scope that difference is what separates a guiding graph that settles from one that wanders.
ApertureDeep
60 mm
Sixty millimetres gathers four times the light of a 30 mm guider and reaches roughly a magnitude and a half deeper. The practical result is that you stop caring which way the telescope is pointed: even a sparse field near the galactic poles will offer a usable guide star without slewing to find one.
Focal ratioFast
f/4
Fast for its aperture, which keeps guide exposures down to a second or two despite the longer focal length. That matters because a short guide exposure lets the software cancel a drift while it is still developing, rather than reporting an error already written into the image.
Length and massSubstantial
270 mm tube
This is the specification that should make you hesitate. A 270 mm tube with rings and a rail is real weight hanging off the front of your imaging scope, and it comes out of the same payload budget as your camera and filter wheel. On a mount already near its limit, adding this to fix guiding can easily make guiding worse.
Optical designGuiding only
Achromatic doublet
Ordinary crown and flint glass, so bright stars carry a violet halo. Guiding software measures a centroid and does not care. A photograph would, which is why this is a guider and not a small imaging refractor despite being large enough to look like one.
Optical
Aperture60 mm
Focal length240 mm
Focal ratiof/4
LensAchromatic refractor, fully multi-coated
Physical
FocuserHelical, 8 mm of travel
Camera connection1.25 inch
Tube diameter66 mm
Dew cap diameter69 mm
Total length270 mm
MountingTube rings and dovetail rail included
MaterialAluminium alloy
03Before you buy

Good to know.

The honest caveats — the things that save you a return, a bad first night, or a second purchase you didn't need.

The honest caveats — the things that save you a return, a bad first night, or a second purchase you didn't need.

This is a specialist, not an upgrade.
Bigger is not better here, it is better matched. On a 700 mm refractor this tube guides no more accurately than a 30 mm and costs you payload you could have spent on a camera. Buy it because your main scope is long, not because it is the biggest one on the page.
At this focal length, consider an off-axis guider instead.
A separate guide tube cannot detect the main scope's own mirror shifting, and mirror flop is a real problem on long Schmidt-Cassegrains. An off-axis guider looks through the main optics and removes both flexure and flop at once. It is fiddlier to set up and, past about 2000 mm, usually the better answer.
Mount it properly.
A finder shoe is not enough support for 270 mm of tube. Use the included rings and rail on the main dovetail or a saddle, and keep cables from hanging on it.
It will not take pictures.
Sixty millimetres of achromatic glass at f/4 looks like a small imaging refractor and is not one. Guiding software ignores the violet halo around bright stars. A camera will not.
Editor’s Take

There is a temptation to read this page as the best guide scope in the range, and it is not. It is the right one for a narrow set of rigs and the wrong one for most. Guide scope focal length should be matched to your main scope, not maximised, because every millimetre of tube you bolt on top is payload stolen from the mount that is causing your drift in the first place. If you image at 2000 mm, this is a sensible purchase and an off-axis guider is a smarter one. If you image at 700 mm, buy the 30 mm and spend the difference on literally anything else.

— The Skynocular verdict
85/ 100
SVBony SV106 60mm Guide Scope
60 mm f/4 achromatic guide scope · 240 mm focal length · F9177B · $114.29

The largest guide scope in the range, for the rigs that need it: long Schmidt-Cassegrains and big Newtonians, where a mini guider simply cannot see the drift that the main camera is recording.