What is the real focal length of the SVBONY SV555?

SVBONY state 243 mm. Seven of my SV555 frames on an IMX571 camera plate solve at 3.13 to 3.15 arcsec per pixel, which with 3.76 micron pixels is 247 to 248 mm, and a field of 5.4 x 3.6 degrees.

Does the SV555 need a flattener or spacers?

No flattener: it is a five element Petzval with a 44 mm image circle. SVBONY state a standard 55 mm back focus from the M48x0.75 rear thread, with room already left for a filter.

Does the SV555 cover a full-frame sensor?

SVBONY quote a 44 mm image circle, which is full frame. Every capture on this page is on an APS-C IMX571 sensor, where I saw no vignetting; I have not put a full-frame camera on it.

Does the SV555 come with an autofocuser?

No. The EAF mount kit is in the box, so the focuser is ready for one, but the focus motor itself is not included.

Why do bright stars have halos through the SV555?

Chromatic aberration. At first I wasn't confident I had perfected the focus, but I really had to make it pinpoint for the dual-band filter, and the halos stayed.

Is the SV555 better than the SV545?

Not for me. The SV555 has more aperture (54 mm against 45 mm) and a longer focal length (243 mm against 203 mm), so its field is smaller, but its images were no better than my SV545's.

Which camera and filter took these SV555 images?

Both captures here are on my SVBONY SC571CC, a cooled 26 megapixel IMX571 colour camera, at -10 C, and the Sadr and Crescent Nebula frame adds the SVBONY SV220 dual-band filter.

What does the SVBONY SV555 cost and where can I buy it?

The prices I recorded: £509 at First Light Optics (UK), awaiting stock; $580 at B&H Photo Video (US), in stock; $640 at SVBONY (Global), in stock.

What have I not tested on the SV555?

I have not tested the SV555 on a full-frame sensor, on the planets or the Moon, or against another telescope on the same night.

SVBONY SV555 review: not a bad deal, not an exceptional one

Where does it rank on our leaderboard

Nine of the 42 telescopes on my board, against price
Rank	Telescope	Stars for Your Buck	Recorded UK price
1	Askar 50P	95 out of 100	£299
2	ToupTek Hope D60	93 out of 100	£749
5	Celestron 8" EdgeHD	90 out of 100	£1,999
16	SVBONY SV555	79 out of 100	£509
18	Celestron C11 EdgeHD	75 out of 100	£4,845
22	ZWO FF110	73 out of 100	£1,499
40	Celestron 63ED	43 out of 100	£322
41	Celestron 114 LCM	42 out of 100	£361
42	Celestron AstroMaster LT 76	13 out of 100	£200

Contents

01 Where does it rank on our leaderboard
02 Specifications and features
03 In the hand
04 How good is it? Here's what I captured
05 Raw against finished
06 The rig on the mount
07 What is it for
08 Tested numbers and the download
09 Should you buy it?
10 Questions and more about this review

In 30 seconds

Stars for Your Buck 79/100

Reviewed 22 Mar 2026 Updated 22 Sep 2026

Rank: #16 of 42 telescopes
Verdict: Damon recommends

Written by Damon Scotting 5 min read

Buy it if

You want large nebulae framed whole at 243 mm: the North America and Pelican nebulae fit together on an APS-C sensor.
You image nebulae through a dual-band filter, which isolates the nebulosity and keeps the star colours in check.
You want the autofocuser mount kit, handle, dovetail and filter holder in the box.

Skip it if

You want pinpoint stars on bright broadband targets: expect some chromatic aberration and rather large star halos.
You already own the SV545: the SV555 is on par with it, not an upgrade.
You want a dual-speed focuser: the SV555 focuses with a helical ring.

“For this review I was really just expecting to be taking some better images compared to the shots I got with the SV545, but sadly that's not been the case.”

Specifications and features

Against the telescopes I have reviewed

Compare with

SVBONY SV555 reviewed #16 of 42	Askar 50P #1 of 42	ToupTek Hope D60 #2 of 42	SVBONY SV545 #9 of 42	Askar SQA55 #12 of 42	William Optics RedCat 51 #29 of 42
Recorded UK price	£509	£299	£749	£459	£795	£849
Stars for Your Buck	79/100	95/100	93/100	85/100	82/100	69/100
Aperture	54 mm	50 mm	60 mm	45 mm	55 mm	51 mm
Focal length	243 mm	190 mm	280 mm	203 mm	264 mm	250 mm
Focal ratio	f/4.5	f/3.8	f/4.66	f/4.5	f/4.8	f/4.9
Optical design	Petzval, 5 elements in 3 groups	Quadruplet Petzval, one SD element	Five element planar apochromat, built-in flattener	Petzval, 5 elements in 3 groups	Quintuplet Petzval, SD and ED elements	Four element Petzval, FPL-53
Image circle	44 mm	APS-C, optimised for 1 inch sensors	44 mm	44 mm	44 mm	48 mm
Back focus	55 mm	55 mm	55 mm	55 mm camera-train spacing has been used successfully by owners; maximum/minimum usable spacing not established	55 mm	55 mm
Focuser	Helical, lockable 360 degree rotator	Single-speed focus ring, 15 mm travel, rotator	3 inch dual-speed rack and pinion, 30 mm travel, rotator	Helical, lockable 360 degree rotator	Dual-speed focus ring, separate coarse and fine controls, MXL teeth	Internal rack and pinion (WIFD), EAF ready
Weight, tube	2.45 kg	1.4 kg with tube ring and dovetail plate	About 3.5 kg as supplied, not a bare-tube figure	0.98 kg, tube only	1.84 kg, 2.18 kg with handle and dovetail	1.77 kg OTA, 2.38 kg total
Length, tube	not recorded	147 mm retracted, 182 mm extended	255 mm, dew shield retracted	not recorded	316 mm with dew shield	298 mm
Dew shield	Lens hood, 93 mm	Retractable	Retractable, magnetic	Removable	Removable	Fixed
In the box	EAF mount kit, handle with Vixen saddle, dovetail, camera angle adjuster, 2 inch filter holder, lens cover, padded case	Tube with ring and dovetail, manual	Tube ring, dovetail, handle, M48 adapter, tilt adjuster, caps	EAF mount kit, handle with Vixen saddle, dovetail, camera angle adjuster, 2 inch filter holder, case	Tube, waterproof hard case	Bahtinov mask cap, M48 adapter, plate, ring with handle, case

In the hand

On the ZWO AM3N with the SC571CC

Lens hood and carry handle

Lens cap inside the hood

Rotator scale

Handle bracket and dovetail

54 mm f/4.5 front element

How good is it? Here's what I captured

Two targets

Sadr region (IC 1318) and the Crescent Nebula (NGC 6888), SVBONY SC571CC, SVBONY SV220 dual-band

Integration: 54 min (18 x 180 s)
Field: 5.4 x 3.6 degrees
Telescope: SVBONY SV555
Camera: SVBONY SC571CC
Mount: Unknown
Target: Sadr region (IC 1318) and the Crescent Nebula (NGC 6888)
Type: Emission nebulae
Location: Bortle 6.8 (in my garden)

North America Nebula (NGC 7000) and Pelican Nebula (IC 5070), SVBONY SC571CC

Integration: 2 h 45 min (55 x 180 s)
Field: 5.4 x 3.6 degrees
Telescope: SVBONY SV555
Camera: SVBONY SC571CC
Mount: Unknown
Target: North America Nebula (NGC 7000) and Pelican Nebula (IC 5070)
Type: Emission nebula
Location: Bortle 6.8 (in my garden)

As you can see with this shot of the North America Nebula, it looks fantastic, but the stars leave a lot to be desired.

Raw against finished

The rig on the mount

The 2 targets, the raw combined stack against my finished image, each with its integration, the camera and the palette:

North America Nebula (NGC 7000) and Pelican Nebula (IC 5070): 2 h 45 min (55 x 180 s) of light, SVBONY SC571CC, the raw combined stack with one automatic stretch
Sadr region (IC 1318) and the Crescent Nebula (NGC 6888): 54 min (18 x 180 s) of light, SVBONY SC571CC, SVBONY SV220 dual-band, the raw combined stack with one automatic stretch

On the TeSeek 11, then on six other mounts

What is it for

Three things it is for

Nebulae through a dual-band filter

I pointed the telescope at the star Sadr and the nearby Crescent Nebula through a dual-band filter. Now that is stunning, isn't it?

A full-frame image circle

The telescope boasts a whopping 44 mm image circle, meaning it should be making light work of a 26 megapixel IMX571 sensor.

Helical focusing

As opposed to using a common dual speed focuser, the SV555 adopts a helical design.

Tested numbers and the download

Finished image

Licence: for personal use, credit Damon Scotting. Both JPEGs 4,096 x 2,738 px.

-10 C sensor temperature during imaging set point -10 C

247 mm focal length, plate solved SVBONY states 243 mm

5.44 x 3.64° field of view 6,248 x 4,176 px on SVBONY SC571CC

26 MP SVBONY SC571CC 6,248 x 4,176 px, 23.5 x 15.7 mm

Should you buy it?

79/100 Stars for Your Buck

Pros

“It's clear that this telescope doesn't suffer from any vignetting when partnered with this camera.”
“The filter has done a fantastic job of isolating the nebulosity and also leaving less to be concerned about with the star colours.”
“Although like most telescopes it does not come with an automatic focuser, it does come with all the gear necessary to mount one.”
A 54 mm, five element Petzval at this price is a potential bargain.

Cons

“There just seems to be a decent amount of chromatic aberration across the board, rather large star halos.”
“Even with an electronic focuser installed, I still didn't feel like the telescope was perfectly focused. The stars did not give me that pinpoint feel.”
“I'm content with it, but certainly not as impressed as I was with the SV545.”

Not a bad deal by any means, but also not an exceptional deal.

Who the SV555 is for

Wide-field nebula imager on an APS-C camera

Buy

At 243 mm the North America and Pelican nebulae fit in one frame, with no vignetting on an APS-C sensor.

Dual-band nebula imager

Buy

Pair it with a dual-band filter: my Sadr and Crescent Nebula frame through one is stunning.

Buyer who wants a complete kit

Buy

The autofocuser mount kit, a handle with a Vixen saddle, the dovetail, a camera angle adjuster and a 2 inch filter holder all come in the box.

Imager who wants pinpoint stars

Skip

Bright stars carry rather large halos and some colour fringing; my recommendation is the Askar SQA55, a quintuplet with a 44 mm image circle that covers APS-C with room to spare.

SV545 owner thinking of upgrading

Skip

Keep the SV545: the bigger SV555 gives a tighter field but no better images.

Buyer who wants a dual-speed focuser

Skip

The SV555 focuses with a helical ring; my recommendation is the ToupTek Hope D60, with a dual-speed rack and pinion and a higher score on my board.

Three alternatives I have reviewed

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

Nine questions, answered

Questions about the SVBONY SV555

Reviewed 22 March 2026 ·Updated 22 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 is the real focal length of the SVBONY SV555? SVBONY state 243 mm. Seven of my SV555 frames on an IMX571 camera plate solve at 3.13 to 3.15 arcsec per pixel, which with 3.76 micron pixels is 247 to 248 mm, and a field of 5.4 x 3.6 degrees. Tested numbers and the download ↓
Does the SV555 need a flattener or spacers? No flattener: it is a five element Petzval with a 44 mm image circle. SVBONY state a standard 55 mm back focus from the M48x0.75 rear thread, with room already left for a filter. The specifications and the comparison table ↓
Does the SV555 cover a full-frame sensor? SVBONY quote a 44 mm image circle, which is full frame. Every capture on this page is on an APS-C IMX571 sensor, where I saw no vignetting; I have not put a full-frame camera on it. What I captured ↓
Does the SV555 come with an autofocuser? No. The EAF mount kit is in the box, so the focuser is ready for one, but the focus motor itself is not included. The specifications and the comparison table ↓
Why do bright stars have halos through the SV555? Chromatic aberration. At first I wasn't confident I had perfected the focus, but I really had to make it pinpoint for the dual-band filter, and the halos stayed. The raw stacks against the finished images ↓
Is the SV555 better than the SV545? Not for me. The SV555 has more aperture (54 mm against 45 mm) and a longer focal length (243 mm against 203 mm), so its field is smaller, but its images were no better than my SV545's. The specifications and the comparison table ↓
Which camera and filter took these SV555 images? Both captures here are on my SVBONY SC571CC, a cooled 26 megapixel IMX571 colour camera, at -10 C, and the Sadr and Crescent Nebula frame adds the SVBONY SV220 dual-band filter. What I captured ↓
What does the SVBONY SV555 cost and where can I buy it? The prices I recorded: £509 at First Light Optics (UK), awaiting stock; $580 at B&H Photo Video (US), in stock; $640 at SVBONY (Global), in stock. A record, not a live price
What have I not tested on the SV555? I have not tested the SV555 on a full-frame sensor, on the planets or the Moon, or against another telescope on the same night.