What focal length and guiding scale does the SV165 give?

120 mm at f/4. With the ZWO ASI120MM Mini's 3.75 micron pixels that is about 6.4 arcseconds per pixel (206.265 x 3.75 / 120).

Which guide camera did I use with the SV165?

The ZWO ASI120MM, on the ToupTek Hope D60 rig in my ASI 4400MC review. On my smart binoculars it held an SVBONY SV105 camera instead, as a plate-solving finder.

Is the SV165 a 30 mm or a 40 mm guide scope?

Both are sold under the SV165 name. Mine is the 30 mm f/4 with a 120 mm focal length (SVBONY part W9125A); the 40 mm f/4 is part W9125B with a 160 mm focal length.

What have I not tested on the SV165?

I have not measured the SV165's guiding error against a 50 mm guide scope on the same night.

SVBONY SV165 review: the 30mm f/4 mini guide scope I use

Where does it rank on our leaderboard

Nine of the 46 accessories on my board, against price
Rank	Accessory	Stars for Your Buck	Recorded UK price
1	GEMINI EAF	100 out of 100	£42
2	Generic Dew Heater	93 out of 100	£9
3	SVBONY Guide Scope 30mm f/5	93 out of 100	£57
6	Generic Guide Scope 50mm	88 out of 100	£41
16	White light solar filter	78 out of 100	£17
30	Celestron 0.63x Reducer	62 out of 100	£165
36	Celestron 2x Barlow	46 out of 100	£135
45	SKY ROVER 2x54 Binoculars	28 out of 100	£139
46	365 Solar Telescope Cover	5 out of 100	£73

Contents

01 Where does it rank on our leaderboard
02 Specifications and features
03 In use
04 In my words
05 Watch it in my videos
06 Should you buy it?
07 Questions and more about this review

In 30 seconds

Stars for Your Buck 93/100

Reviewed 30 Jan 2026 Updated 25 Sep 2026

Rank: #3 of 46 accessories
Verdict: Damon's pick

Written by Damon Scotting 2 min read

Buy it if

You want the lightest guide scope for a small refractor or a portable rig
You guide with a small camera such as the ZWO ASI120MM Mini
You want a small finder that a camera can plate solve through

Skip it if

You guide a long focal length telescope and want a finer guiding scale than 120 mm gives
You image under a bright sky and want the extra light of a 50 mm guide scope

The SV165 is the 30 mm f/4 mini guide scope I have used on the ToupTek Hope D60 with an ASI120MM guide camera, and as the finder of my DIY smart binoculars: 120 mm of focal length in a 342 g scope.

Specifications and features

SVBONY Guide Scope 30mm reviewed #3 of 46
Recorded UK price	£57
Aperture	30 mm
Focal length	120 mm
Focal ratio	f/4
Focuser	Helical
Camera connection	1.25 inch and M42 x 0.75
Back focal length	26 mm
Weight	342 g
Length	112 mm
Tube diameter	45 mm
Mounting	Two-ring bracket with a dovetail; UNC 1/4-20 mount interface
In the box	Guide scope, two-ring bracket with dovetail, two thumbscrews, tool, dust cover, lens cover
Part number	W9125A

In use

Two frames from my videos

Guiding the ToupTek Hope D60

The finder of my smart binoculars

In my words

“Now with the help of our mini telescope and camera we can plate solve our view of the night sky and receive directions from SharpCap towards whatever deep sky object we are looking for.”

From one of my videos

Watch it in my videos

I Captured a Gigapixel Orion Mosaic! - ASI 4400MC Review · published 30 January 2026 · 6:48 · Watch on YouTube · 49,833 views, 1,148 likes on 2 Oct 2026

Jump to

3:33 Mosaic imaging 2
3:44 The guide rig: the SVBONY 30 mm and an ASI120MM on the Hope D60
4:00 Images

Check out more videos on the SVBONY Guide Scope 30mm

Would you TRY these $1,199 SMART BINOCULARS?

17 Dec 2024

What YOU can SEE with a £2000 "USED" Telescope setup?!

12 Jul 2025

Should you buy it?

93/100 Stars for Your Buck

Pros

120 mm of focal length at f/4 from a 30 mm lens, in a scope 112 mm long
342 g by SVBONY's figure
A helical focuser, with 1.25 inch and M42 x 0.75 camera connections
It guided the ToupTek Hope D60 with an ASI120MM guide camera, and held an SVBONY SV105 camera as the plate-solving finder of my binoculars

Cons

A 30 mm lens gathers about a third of the light of a 50 mm guide scope ((30/50) squared is 0.36)
At 120 mm the guiding scale is coarse: about 6.4 arcseconds per pixel with the ASI120MM Mini's 3.75 micron pixels
SVBONY also sells a 40 mm f/4 scope under the SV165 name (part W9125B): the 30 mm is part W9125A

It's a very portable and powerful setup.

Three alternatives

Questions and more about this review

Reviewed by

Damon Scotting

The Telescope Man Verified

BSc (Hons) Physics with Astrophysics and Cosmology, Loughborough University PGCE / QTS, University of Nottingham

About Damon About Damon Damon Scotting is The Telescope Man. He holds a BSc (Hons) in Physics with Astrophysics and Cosmology from Loughborough University and a PGCE with QTS from the University of Nottingham, and taught physics in secondary schools before becoming an astronomy creator. He is a contributing writer for BBC Sky at Night Magazine and the author of 42 Wonders of Our Night Sky, and his photograph of the galaxy M100 with the dwarf planet Ceres was Highly Commended in the Astronomy Photographer of the Year 2024 competition run by Royal Observatory Greenwich. He has appeared on the BBC's Blue Peter. More than 750,000 people follow his astronomy channels on YouTube, Instagram and TikTok, and he has reviewed more than 140 telescopes, mounts, cameras, filters and accessories hands-on for this site. More about Damon · How I test · Damon's book

I review all kinds of gear: most of it I buy, some is gifted and some is loaned, and all of it is reviewed the same way. How this site is funded

Four questions, answered

Questions about the SVBONY Guide Scope 30mm

Reviewed 30 January 2026 ·Updated 25 September 2026

I review all kinds of gear. Most of it I buy, some is gifted and some is loaned, and all of it is reviewed the same way: no company sees or approves a review before it is published. Shop links marked Ad are affiliate links: I earn a commission when you buy through them, at no extra cost to you. How this site is funded

What focal length and guiding scale does the SV165 give? 120 mm at f/4. With the ZWO ASI120MM Mini's 3.75 micron pixels that is about 6.4 arcseconds per pixel (206.265 x 3.75 / 120). The specifications ↓
Which guide camera did I use with the SV165? The ZWO ASI120MM, on the ToupTek Hope D60 rig in my ASI 4400MC review. On my smart binoculars it held an SVBONY SV105 camera instead, as a plate-solving finder. In use ↓
Is the SV165 a 30 mm or a 40 mm guide scope? Both are sold under the SV165 name. Mine is the 30 mm f/4 with a 120 mm focal length (SVBONY part W9125A); the 40 mm f/4 is part W9125B with a 160 mm focal length. The specifications ↓
What have I not tested on the SV165? I have not measured the SV165's guiding error against a 50 mm guide scope on the same night.