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The RedCat 51 Mono Astrophotography Kit is a complete, guided monochrome imaging system for LRGB and narrowband (SHO / Hubble palette) deep-sky imaging. It pairs the William Optics RedCat 51 WIFD III with the ZWO ASI2600MM Pro cooled monochrome camera, a 7-position electronic filter wheel filled with Optolong LRGB and 7nm SHO filters, and your choice of ZWO AM3N or AM5N harmonic mount.
Everything runs from your phone or tablet with the ZWO ASIAIR Plus, including plate solving, autoguiding, autofocus, filter changes and multi-night imaging sequences.
Note: This is a complete astrophotography system, not a push-button smart telescope. Setup, polar alignment and image processing experience are required. Monochrome imaging takes more time and processing than color imaging, and rewards it with more detail and more control over the final image.
What's Included
- William Optics RedCat 51 WIFD III, 250mm f/4.9 Petzval APO (with Bahtinov mask cap, rings, dovetail and soft case)
- ZWO ASI2600MM Pro (2025 model) cooled APS-C monochrome camera
- ZWO 7-position electronic filter wheel for 2" filters (2025 model)
- Optolong 2" LRGB filter set (luminance, red, green, blue)
- Optolong 2" 7nm SHO narrowband filter set (sulfur-II, hydrogen-alpha, oxygen-III)
- ZWO harmonic mount with TC40 carbon fiber tripod: choose AM3N (17/28 lb payload) or AM5N (33/44 lb payload)
- ZWO pier extension (PE160 with the AM3N, PE200 with the AM5N) and tripod carry case
- ZWO ASIAIR Plus 256GB smart controller
- William Optics UniGuide 32 guide scope
- ZWO ASI220MM Mini guide camera
- ZWO EAFN electronic autofocuser
- ZWO 12V 10A AC power adapter
- One 30-minute tech support session with the Mile High Astronomy team
Why This Setup
- All seven filter slots used. LRGB for galaxies, star clusters and natural-color images, plus Ha, OIII and SII for Hubble-palette narrowband. All seven filters stay installed, so you can switch between broadband and narrowband targets without touching the imaging train.
- The go-to mono camera. The ASI2600MM Pro's 26MP APS-C IMX571 sensor is one of the most-used monochrome deep-sky cameras on AstroBin, with 16-bit output, zero amp glow and regulated cooling.
- Narrowband beats light pollution. 7nm narrowband filters let you capture emission nebulae from the city, under a bright Moon, or from Front Range suburbs.
- A proven wide-field scope. The RedCat 51 has a flat field across full-frame sensors and an internal focuser that holds focus through long filter sequences.
- Harmonic mount with guiding included. The imaging payload is roughly 10 lb, well within either mount's no-counterweight rating, and the UniGuide 32 with ASI220MM Mini provides the autoguiding that harmonic mounts need.
Imaging Specifications
| Focal length / ratio | 250mm, f/4.9 |
|---|---|
| Field of view (ASI2600MM Pro) | approximately 5.4° × 3.6° |
| Image scale | approximately 3.1 arcseconds per pixel |
| Camera sensor | Sony IMX571 APS-C monochrome, 6248 × 4176, 3.76µm pixels |
| Filters | Optolong 2" mounted: L, R, G, B, Ha 7nm, OIII 7nm, SII 7nm |
| Mount payload (no counterweight) | AM3N: 17 lb / AM5N: 33 lb |
| Control | ZWO ASIAIR app (iOS and Android) |
What You'll Need
- A phone or tablet with the free ASIAIR app
- Image processing software for combining filter channels (for example Siril, which is free, or PixInsight)
- AC power, or a 12V battery or portable power station for dark-site use (not included)
- Optional: a dew heater strap and controller for humid or cold nights
Frequently Asked Questions
Should I choose a mono or a color camera?
Mono cameras capture more detail per filter and excel at narrowband imaging from light-polluted areas, but each image takes more exposure time and processing. If you want simpler, faster results, see our RedCat 51 Color Astrophotography Kit.
Should I choose the AM3N or the AM5N?
Both carry this kit easily without counterweights. Choose the AM3N for the lightest, most portable setup. Choose the AM5N if you expect to add a larger telescope, such as an 80–100mm refractor, in the future.
What can I photograph with this kit?
The 5.4° × 3.6° field of view suits large emission nebulae in narrowband, such as the Heart and Soul Nebulae, the North America and Pelican Nebulae, the Veil Nebula complex and the Rosette Nebula, and wide galaxies and clusters in LRGB, such as the Andromeda Galaxy and the Pleiades.
What is the SHO or Hubble palette?
SHO images map sulfur-II, hydrogen-alpha and oxygen-III light to red, green and blue, the same approach used for many Hubble Space Telescope images. It reveals structure in emission nebulae that broadband color cannot show.
Do I need a computer?
Not to capture images. The ASIAIR Plus runs the camera, filter wheel, mount, guiding and autofocus from your phone or tablet. You will need a computer to process and combine your images.
Is this a smart telescope?
No. It is a modular imaging system that delivers far more detail and flexibility than smart telescopes, but it requires setup and processing experience. The included support session helps you get started.