SVBONY SV545 45mm f/4.5 Petzval APO Astrograph Lens

Product Overview

The SVBONY SV545 is a 45 mm, 203 mm focal length Petzval apochromatic astrograph working at f/4.5. It uses a five-element, three-group objective with fully multi-coated (FMC) optics and a built-in flat field, so stars stay round toward the edge of the frame without a separate flattener. A one-piece helical focuser, a lockable 360° rotator and an M48x0.75 male thread at the back make it a compact, self-contained wide-field imaging lens.

SVBONY ships it with an EAF mount kit, a carry handle with an integrated Vixen-style finder saddle, a dovetail plate, a camera angle adjuster, a 2″ filter holder already assembled to the lens, front and rear covers and a soft padded case.

Who It's For

This is a good match if you:

• Image large deep-sky fields: 203 mm of focal length frames big emission nebulae, dark-nebula regions and star fields such as Cygnus, Orion and the Milky Way core.
• Want a fast, portable rig: f/4.5 keeps sub-exposures short, and the short tube rides on compact star trackers and small equatorial mounts.
• Prefer a simple imaging train: the flat field is built in, so the camera threads straight to the M48 back without a corrector.
• Plan to automate focus: the helical focuser is prepared for an electronic auto focuser, and the EAF mount kit is included.

It works well as a first dedicated astrograph and as a wide-field companion to a longer imaging telescope.

Key Features & Design

• Petzval APO objective: five elements in three groups, fully multi-coated.
• 45 mm aperture, 203 mm focal length, f/4.5: a short, fast focal length for wide-field framing.
• Built-in flat field: no external flattener is needed for edge-to-edge star shapes.
• Helical focuser: one-piece integrated focusing, prepared for an EAF with the included mount kit.
• Lockable 360° rotator: frame the target without loosening the camera.
• M48x0.75 male back thread: standard connection for astronomy cameras, filter wheels and DSLR T-rings.
• 2″ filter holder: supplied already assembled to the lens.
• All-metal body: SVBONY describes sealed construction with protective coatings for humid or dusty conditions.

Optical Design

A Petzval astrograph splits its optics into a front objective group and a rear corrector group spaced inside the tube. Because the field-flattening group is part of the design, the focal plane arrives flat at the camera without an add-on corrector, and there is no backfocus spacer stack to tune for the flattener. SVBONY's 3-group, 5-element layout keeps the element count moderate for optical consistency and a compact body, while the fully multi-coated surfaces control reflections around bright stars.

At f/4.5 and 203 mm the SV545 gathers signal quickly and covers a wide patch of sky, which suits broadband colour imaging under dark skies as well as narrowband or dual-band work from the suburbs.

Recommended Uses

• Wide-field nebula imaging: North America and Pelican, Cygnus Loop, Rosette, Orion's Sword and Heart and Soul regions fit comfortably.
• Milky Way star fields: rich star clouds and dark-nebula regions at a short focal length.
• Narrowband and dual-band imaging: through the included 2″ filter holder.
• Travel imaging: a compact lens that packs into its padded case with the accessories.

Compatibility and Accessory Notes

• Camera connection: M48x0.75 male thread at the back. SVBONY states the standard threads and back focus suit DSLRs, astronomy cameras and filter wheels without extra adapters.
• Filters: 2″ filters mount in the supplied filter holder.
• Focusing: manual helical focus, with an EAF mount kit included for an electronic focuser.
• Mounting: dovetail plate supplied; the handle carries a Vixen-style finder saddle for a guide scope or finder.
• Framing: lockable 360° rotator plus a camera angle adjuster in the box.

If you want to check a particular camera, filter wheel or guider against the SV545's back end, send us your setup and we will work through the spacing with you.

What's in the Box

• 1 x SV545 astro APO camera lens
• 1 x EAF mount kit
• 1 x handle with integrated Vixen-style finder saddle
• 1 x dovetail plate
• 1 x camera angle adjuster
• 1 x 2″ filter holder (assembled to the lens)
• 1 x plastic lens cover
• 1 x M48 metal lens cover
• 1 x soft padded case
• Wrench and screws
• 1 x instruction manual

Good to Know Before You Order

• Imaging lens: the SV545 is built as an astrograph for cameras. It has no diagonal or eyepiece in the box.
• Weight figure: SVBONY publishes an estimated weight of 2750 g and does not state whether it is the bare lens or the packed kit.
• Mount and camera sold separately: the lens needs a tracking mount and a camera; the SVBONY add-ons on this page cover filters and imaging accessories.
• Style option: SVBONY also offers an SV545 Photography Set; this listing is the SV545 OTA style.

Frequently Asked Questions

Is it difficult to set up?

No. The flat field is built in, so the camera threads onto the M48 back, the rotator sets framing, and the helical focuser brings stars to focus. There is no external flattener spacing to work out.

Does it need a field flattener?

No. SVBONY designs the SV545 with a built-in flat field for edge-to-edge stars.

Can I add an electronic focuser?

Yes. The focuser is prepared for an EAF, and the EAF mount kit is in the box.

What filters does it take?

2″ filters, in the 2″ filter holder supplied assembled to the lens.

Will it work with a DSLR?

Yes, through an M48 T-ring for your camera body. Astronomy cameras connect to the same M48x0.75 thread.

What is it best used for?

Wide-field deep-sky imaging of large nebulae and Milky Way regions at 203 mm and f/4.5.

Bottom Line

In short: a 45 mm, 203 mm f/4.5 Petzval astrograph with a built-in flat field, helical EAF-ready focuser, lockable rotator, 2″ filter holder and M48 back, supplied with handle, dovetail and padded case. Add a camera and a tracking mount and it is ready for wide-field imaging.