What focal length does a 0.63x reducer give on a Celestron C5?

Nominally 788 mm at f/6.3. At the spacing I used with a ZWO ASI533MC Pro, my C5 frames plate-solved at 0.78 arcsec per pixel, which is 996 mm, about f/8: the reduction depends on the distance between the reducer and the sensor.

What did I capture through the generic reducer?

On my C5 with a ZWO ASI533MC Pro on the JUWEI-14: the Pinwheel Galaxy, Bode's Galaxy, the Needle Galaxy, the globular clusters M 13 and M 3, and Mizar and Alcor. They are all on this page, with the raw stacks behind the finished frames.

How does the C5 with this reducer compare with an 8 inch EdgeHD?

At 7:47 in the video the C5's Pinwheel and M 13 through this reducer sit beside the same targets from my 8 inch EdgeHD with its 0.7x reducer, both on a 533 colour camera. The EdgeHD's images are better, but are they ten times better? That is the question for your money.

How much does the generic 0.63x reducer cost?

The prices I recorded: £54 at AliExpress (BestGoBuy Store), Global, in stock.

What have I not tested on the 0.63x Reducer?

I have not measured star shapes across the field or found the spacing that gives the full 0.63x.

Generic 0.63x Reducer review: the Angeleyes f/6.3 on my C5

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
5	Generic 0.63x Reducer	88 out of 100	£54
13	ASIAIR Plus 256GB	81 out of 100	£399
19	Green laser pen	76 out of 100	£10
33	ZWO EAF	51 out of 100	£199
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 What I captured through it on my C5
04 Raw against finished
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 88/100

Reviewed 9 Jul 2025 Updated 26 Sep 2026

Rank: #5 of 46 accessories
Verdict: Damon's pick

Written by Damon Scotting 3 min read

Buy it if

You image with a standard f/10 Schmidt-Cassegrain (a C5 to a C14) and want a wider, faster field for galaxies and clusters.
You are happy to find the spacing to your camera yourself in return for a much lower price.

Skip it if

You own an EdgeHD: those tubes need the 0.7x reducer matched to their aperture.
You mainly image planets: they want the full f/10 or longer, not a reducer.

This generic f/6.3 reducer is what let me image galaxies with my Celestron C5, though at the spacing I used my frames plate-solved at 996 mm: a 0.80x reduction rather than the full 0.63x.

AliExpress £54 Ad

Specifications and features

Generic 0.63x Reducer reviewed #5 of 46
Recorded UK price	£54
Type	Focal reducer-corrector for Schmidt-Cassegrain telescopes
Brand	Angeleyes
Reduction, as sold	0.63x (f/10 to f/6.3)
Reduction I measured	0.80x on my Celestron C5: 996 mm from 1,250 mm, plate-solved
Fits	Celestron C5, C6, C8, C9.25, C11 and C14 (standard SCT rear thread)
Not for	EdgeHD optical tubes
Camera I used it with	ZWO ASI533MC Pro

What I captured through it on my C5

Six targets

M 101 Pinwheel Galaxy, ASI533MC Pro

Integration: 30 min (30 x 60 s)
Field: 0.63 x 0.42 degrees
Telescope: Celestron C5
Camera: ZWO ASI533MC Pro
Mount: JUWEI-14
Target: M 101 Pinwheel Galaxy
Type: Spiral galaxy
Location: Bortle 6.8 (in my garden)

M 13 Great Globular Cluster in Hercules, ASI533MC Pro

Integration: 57 min (57 x 60 s)
Field: 0.63 x 0.42 degrees
Telescope: Celestron C5
Camera: ZWO ASI533MC Pro
Mount: JUWEI-14
Target: M 13 Great Globular Cluster in Hercules
Type: Globular star cluster
Location: Bortle 6.8 (in my garden)

NGC 4565 Needle Galaxy, ASI533MC Pro

Integration: 12 min (12 x 60 s)
Field: 0.63 x 0.42 degrees
Telescope: Celestron C5
Camera: ZWO ASI533MC Pro
Mount: JUWEI-14
Target: NGC 4565 Needle Galaxy
Type: Edge-on spiral galaxy
Location: Bortle 6.8 (in my garden)

M 81 Bode's Galaxy, ASI533MC Pro

Integration: 2 h 21 min (47 x 180 s)
Field: 0.61 x 0.41 degrees
Telescope: Celestron C5
Camera: ZWO ASI533MC Pro
Mount: JUWEI-14
Target: M 81 Bode's Galaxy
Type: Spiral galaxy
Location: Bortle 6.8 (in my garden)

M 3 globular cluster, ASI533MC Pro

Integration: 15 min (46 x 20 s)
Field: 0.63 x 0.42 degrees
Telescope: Celestron C5
Camera: ZWO ASI533MC Pro
Mount: JUWEI-14
Target: M 3 globular cluster
Type: Globular star cluster
Location: Bortle 6.8 (in my garden)

Mizar and Alcor, Unknown

Integration: 21 min
Field: 0.62 x 0.41 degrees
Telescope: Celestron C5
Camera: Unknown
Mount: JUWEI-14
Target: Mizar and Alcor
Type: Double star
Location: Bortle 6.8 (in my garden)

Raw against finished

Watch it in my videos

The 3 targets, the raw combined stack against my finished image, each with its integration, the camera and the palette:

M 101 Pinwheel Galaxy: 30 min (30 x 60 s) of light, ASI533MC Pro, the raw combined stack with one automatic stretch
M 13 Great Globular Cluster in Hercules: 57 min (57 x 60 s) of light, ASI533MC Pro, the raw combined stack with one automatic stretch
M 81 Bode's Galaxy: 2 h 21 min (47 x 180 s) of light, ASI533MC Pro, the raw combined stack with one automatic stretch

I Pointed a £200 TELESCOPE at JUPITER!? (+ Bonus stuff) · published 9 July 2025 · 8:52 · Watch on YouTube · 21,158 views, 991 likes on 2 Oct 2026

Jump to

6:01 The 0.63x focal reducer
6:18 The Needle Galaxy through it
6:40 The Pinwheel Galaxy
6:45 M 13, the Hercules cluster
7:31 Against the 8 inch EdgeHD and its 0.7x reducer
7:47 The two side by side

Transcript of the video 223 words · 3 chapters · searchable

Press a time stamp to play from there.

6:01 The 0.63x focal reducer

6:01 So to help me out I'm using a focal reducer. 6:01 With the help of this little attachment I'm going to reduce my focal ratio from f/10 to f/6.3. 6:05 Which in short means that under the same exposure times objects will now appear precisely two and a half times brighter than before. 6:14 Which is a huge plus. 6:14 Allowing me to try and tackle the Needle Galaxy, a perfectly viewed side-on galaxy, which is a super cool, rare perspective of a galaxy.

6:18 The Needle Galaxy through it

6:26 It makes it seem super neat and tidy, with a slight but noticeable bulge around the centre of it, where likely lies a supermassive black hole, helping keep this massive collection of stars together. 6:36 But just to remind ourselves of what a galaxy generally looks like face on, here's my shot of the Pinwheel Galaxy, with its long, spiralling arms.

6:45 M 13, the Hercules cluster

6:45 And then lastly I've decided to try and image one of the gems of our night sky, the great globular cluster in Hercules, Messier object 13. 6:53 This immense collection of over 700,000 stars is an easy target for amateur astronomers. 6:58 These stars are packed so tightly together that some of them often collide and produce new stars. 7:04 Our nearest stellar neighbour is about four and a quarter light years away, meanwhile these stars are on average just 0.1 to 0.3 light years apart.

Should you buy it?

88/100 Stars for Your Buck

Pros

Sold to take an f/10 Schmidt-Cassegrain to f/6.3, a 0.63x reduction.
It opened up deep-sky targets on my C5: the Needle Galaxy, the Pinwheel Galaxy and the globular cluster M 13 were all taken through it.
Made for the standard SCT rear thread of the Celestron C5, C6, C8, C9.25, C11 and C14.
Costs well under half the price of Celestron's own f/6.3 reducer.

Cons

At the spacing I used it gave 0.80x on my C5 (996 mm), not the full 0.63x: the distance to the sensor is yours to find.
Not for EdgeHD tubes, which need the 0.7x reducer matched to their aperture.
The listing states no working distance, weight or warranty, only the brand and the telescopes it suits.

With the help of this little attachment I'm going to reduce my focal ratio from f/10 to f/6.3.

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

Five questions, answered

Questions about the Generic 0.63x Reducer

Reviewed 9 July 2025 ·Updated 26 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 does a 0.63x reducer give on a Celestron C5? Nominally 788 mm at f/6.3. At the spacing I used with a ZWO ASI533MC Pro, my C5 frames plate-solved at 0.78 arcsec per pixel, which is 996 mm, about f/8: the reduction depends on the distance between the reducer and the sensor. The specifications ↓
What did I capture through the generic reducer? On my C5 with a ZWO ASI533MC Pro on the JUWEI-14: the Pinwheel Galaxy, Bode's Galaxy, the Needle Galaxy, the globular clusters M 13 and M 3, and Mizar and Alcor. They are all on this page, with the raw stacks behind the finished frames. What I captured ↓
How does the C5 with this reducer compare with an 8 inch EdgeHD? At 7:47 in the video the C5's Pinwheel and M 13 through this reducer sit beside the same targets from my 8 inch EdgeHD with its 0.7x reducer, both on a 533 colour camera. The EdgeHD's images are better, but are they ten times better? That is the question for your money. Watch it in my videos ↓
How much does the generic 0.63x reducer cost? The prices I recorded: £54 at AliExpress (BestGoBuy Store), Global, in stock. A record, not a live price The verdict, the readers and the sellers ↓
What have I not tested on the 0.63x Reducer? I have not measured star shapes across the field or found the spacing that gives the full 0.63x.