Indigo Filter Wheel

Product Overview

The Pegasus Astro Indigo is a motorized seven-position filter wheel for 2″ mounted or 50 mm unmounted filters (maximum filter diameter 50.8 mm). The body is CNC-machined from 6061 aluminium and measures just 19.0 mm thick — 19.6 mm with the screw slide adapters fitted on both sides — so it takes very little out of your backfocus budget. A direct-drive stepper motor with optical sensing locks each position accurately, and the wheel runs from a single USB 2 Type-B cable with no separate power supply. It weighs 900 g.

Who It's For

This is a good match if you image deep-sky targets with a monochrome camera and want to automate LRGB or narrowband sequences across a night. It also suits remote and observatory rigs, where one cable and full ASCOM, INDI and N.I.N.A. support keep the setup simple, and compact imaging trains where a thin wheel leaves room for an off-axis guider and a corrector within the available backfocus.

Key Features & Design

• Seven-position carousel: holds 2″ mounted or 50 mm unmounted filters, up to 50.8 mm in diameter.
• 19.0 mm body: CNC-milled 6061 aluminium in blue and black anodizing; 19.6 mm with screw slide adapters on both sides.
• Single-cable operation: powered and controlled over USB 2 Type-B (5 V, 300 mA while slewing). A 1.8 m cable is included.
• Direct-drive stepper with optical sensing: moves clockwise or counter-clockwise and takes the shortest path to the selected filter, locking precisely on each position.
• Rotatable M54 interfaces: both sides have M54 openings, and the screw slide adapters let you rotate the camera or telescope side to the orientation you want.
• Direct camera mounting: a 6-hole pattern (62 mm diameter) on the camera side bolts straight to compatible cameras, removing an adapter from the train.

Mechanical Design

The Indigo is built around a dual-type carousel inside a sealed aluminium housing. Filters load into numbered slots clockwise; 2″ mounted filters thread in, and unmounted 50 mm filters are held with four M2 bolts each. Pegasus Astro publishes a 3D-printable filter mask for unmounted filters in 2 mm and 3 mm thicknesses. A stepper motor drives the carousel directly — no belt — and an optical sensor confirms the lock position, so each filter returns to the same place every time. On power-up the wheel initializes and finds position 1 after about four seconds.

Maximum filter height depends on what is attached to the telescope side: 8.0 mm with a 6-hole or 4-hole pattern OAG, 6.4 mm with the M54 female, M54 male or M42 male adapter, and 6.0 mm with the slot cover ring. The wheel needs no lubrication or routine maintenance.

Recommended Uses

• Mono LRGB imaging: run luminance and colour filters in one automated sequence.
• Narrowband imaging: Ha, OIII and SII alongside LRGB in a single seven-slot carousel.
• Remote and observatory operation: one USB cable and serial command support make it easy to run unattended.
• Short-backfocus trains: pair with an off-axis guider and corrector where every millimetre of spacing counts.

Compatibility and Accessory Notes

• Telescope side: M54 female, M54 male and M42 male (0.75 mm pitch), plus 6-hole and 4-hole patterns (62 mm diameter) for direct OAG mounting.
• Camera side: 6-hole pattern (62 mm diameter) for cameras using M3 or M2.5 bolts, a 4-hole pattern for Player One cameras, and an M42 male (0.75 mm) adapter for other cameras.
• Player One cameras: mount directly with four M2.5 bolts once the camera's tilt plate is removed.
• With the Pegasus Astro Indigo OAG: the wheel and OAG together occupy 33 mm (19 mm + 14 mm) of backfocus.
• Software: ASCOM 6 and 7, N.I.N.A., INDI and INDIGO, and the Pegasus Astro Unity Platform (which installs the ASCOM driver). APT, Sequence Generator Pro and SharpCap connect through Unity. A published serial command list supports custom integration.
• Filters: a matched set is available in the Indigo Filter Wheel Bundle with LRGB filters.

If you are working out spacing for a particular camera, corrector and OAG, send us your setup and we will work through the numbers with you.

What's in the Box

• 1 × Indigo Filter Wheel
• 1 × USB 2 cable, 1.8 m
• 2 × slot cover rings
• 1 × M54 female adapter
• 1 × M54 male adapter
• 1 × M42 male adapter
• M2 bolts and washers (for unmounted filters)
• M3 and M2.5 bolts (for adapters and cameras)

Good to Know Before You Order

• Filters are sold separately: the wheel takes 2″ mounted or 50 mm unmounted filters; 1.25″ and 36 mm filters are outside its range. The bundle includes an LRGB set.
• Filter height limits: 8.0 mm, 6.4 mm or 6.0 mm depending on the telescope-side attachment, as listed under Mechanical Design.
• USB-powered: the wheel draws 300 mA from the USB port while slewing, so a powered hub or a port on your mount computer handles it without a separate supply.
• Imaging accessory: it is designed for camera imaging trains and has no application in a visual eyepiece setup.

Frequently Asked Questions

Is it difficult to set up?

No. You open the lid (eight hex bolts), lift out the carousel, bolt your camera to the matching pattern or fit the M42 adapter, then load filters and close it up. Plug in the USB cable and the wheel finds position 1 by itself.

How much backfocus does it use?

The body is 19.0 mm thick, or 19.6 mm with screw slide adapters on both sides. Mounting the camera directly to the 6-hole pattern avoids adding a separate adapter.

Does it need its own power supply?

No. Power and control both run over the single USB 2 Type-B cable.

Which software does it work with?

ASCOM 6 and 7, N.I.N.A., INDI and INDIGO, and Pegasus Astro Unity. APT, Sequence Generator Pro and SharpCap connect through Unity.

Can I use unmounted filters?

Yes. 50 mm unmounted filters are held with four M2 bolts each, and Pegasus Astro offers a 3D-printable mask for 2 mm and 3 mm thick filters.

Will it fit my camera?

Cameras with the 6-hole 62 mm pattern and Player One cameras bolt on directly; others connect through the included M42 male adapter. If you are unsure, tell us your camera model and we will confirm the fit.

How many filters does it hold?

Seven — enough for LRGB plus Ha, OIII and SII in one carousel.

Bottom Line

In short: a 19 mm thin, seven-position 2″/50 mm filter wheel that runs from a single USB cable, bolts directly to common camera patterns, and works with all the major imaging software.