Narrowband Filters
Hα, SII & OIII Filters | SHO Filter Sets
Narrowband Filters - SHO 36mm Narrowband Filters-4nm / Hα Filter is backordered and will ship as soon as it is back in stock.
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For setup support, software downloads and warranty service, contact ToupTek Astro support with your order information.
Reviews (11)
Reviews (11)
Filters are working well, so far I did not notice any halos other other probelems
Honestly im super impressed! at a price point of $500 for the entire set with a bandpass of 3.5/4nm is sceptical to say the least, there is/was concerns for halos or not working at fast (er) Focal ratios, or just generally not producing good results. HOWEVER! those concerns was very quicky gone! after unboxing and installing into the AFW (which was a little difficult to tell which way to go, but just follow the black rims) i was ready! finally a few nights came around and i got to test them. Easily producing my best SHO image ever! much better than my Baader CCD 6.5nm filters did! There is absolutely no halos in my testing, including on bright stars such as Sadr, Vega and Arcturus. And after 3 nights of imaging i got this stunning image of the North America Nebula. 12 hours worth of data, 4 hours per filter!
If you are unsure what filters to go with, or want a cheap option that produces phenomenal results, these are the way to go! Very glad i picked these over anything else around this pricerange or even above! 5 stars from me, absolutely perfect
Shot with SHO 36mm filters (3.5nm 4nm) using Touptek 26k mono paired with 6" F5 newt. Weather is not supportive so i couldn't make more images with this. But in coming months i am planning to test these filters with fast optics and see how it behave.
Good quality
Good narrowband filters, Ha + SII are halo-free, OIII still not used. Ha+SII show not any background gradient.
Thanks Touptek for updating the installation guide ... very satisfied with the performance of all the filters in the EFW
A+
I would have given these a 5* review, however despite the description on the product page it was not entirely obvious which way round to install these in the EFW as both sides appeared to have the same tint and reflection, they really need some form of labelling to resolve this unambiguously
Thank you very much for your suggestion. We have updated this information on the product detail page — please check.
Although i am planning to make a detailed version of these filters, but weather is not on my side. So i could just manage few hours testing these new filters. I paired these SHO filters with Touptek 26k mono camera and fully customised 6" F5 newtonian. As a first light, i shot Rosette nebula and it came out really detailed. I didnt see any halo around bright star. I would test with some other fast optics and see how it performs. Overall, i am very satisfied.
I have yet tested only Ha filter due cloudy weather. For those two nebula targets I have been able to test Ha filter results were great. Looking forward to be able to test also SII and OIII filters.
I have used the filters recently. No halos, amazing details! The filters can easily compete with SHO of other manufacturers that cost two or three times as much than those from Touptek. These filters are one of the best buys that I did in 2024. Thank you Touptek for this amazing product for such unbelievable price. 🙏
I live in a city with very high sky brightness so i am limited to narrow band photography. I've bought a few 36mm unmounted filters in the past with mixed results. The ToupTek 3 nM filter has given me much better results than some more expensive filters. I especially like the way the edges are darkened to reduce reflection and improve contrast. The edge they provide even makes handling the filters a bit easier. I plan on purchasing the Sii and Oiii in the future.
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Narrowband Filters - SHO 36mm Narrowband Filters-4nm / Hα Filter is backordered and will ship as soon as it is back in stock.
ToupTek Astro SHO narrowband filters are precisely tuned to the three main ionized emission lines found in star-forming regions:
- Hα (656.3nm)
- SII (671.6nm)
- OIII (500.7nm)
- H-alpha filter: Central wavelength 656.3nm
- SII filter: Central wavelength 671.6nm
- OIII filter: Central wavelength 500.7nm
- 36mm: H-alpha (3.5nm) / SII (4nm) / OIII (4nm)
- 1.25” & 2”: H-alpha (7nm) / SII (7nm) / OIII (7nm)
Choose your narrowband filters based on sensor size and the bandwidth available for your filter size. ToupTek Astro offers Hα, SII and OIII filters individually or as an SHO filter set.
| Sensor / Setup | Recommended Size | Available Narrowband Options |
|---|---|---|
| 1-inch or smaller sensor | 1.25" | Hα / SII / OIII, 7nm |
| APS-C or smaller sensor | 36mm | Hα 3.5nm / SII 4nm / OIII 4nm |
| Full-frame or smaller sensor | 2" | Hα / SII / OIII, 7nm or 4nm options |
4nm vs 7nm Narrowband Filters
Bandwidth (FWHM) describes the width of the spectral band transmitted by the filter. A narrower bandpass isolates a tighter wavelength range, while a wider bandpass transmits a broader range around the target emission line. Choose from the bandwidth options available for your filter size and imaging setup.
- The horizontal axis represents the wavelength of light (in nm), and the vertical axis represents light transmittance (percentage %).
- Red line: Hα (656nm); Green line: OIII (500.7nm); Blue line: SII (672.4nm).
- Emission nebula signal bands are mainly at 656nm (Hα), 500.7nm (OIII), and similar wavelengths.
- Light pollution peaks are often found near 540nm and 590nm (sodium/mercury lamp bands).
Photographer: voice
Telescope: Sky-Watcher
Mount: UMI
Camera: ToupTek Astro ATR2600M
Filters: ToupTek Astro 36mm LRGB&SHO
Integration: Hα: 30 × 600s ; SII: 30 × 600s ; OIII: 30 × 600s
Total exposure: 15h
Photographer: voice
Telescope: Sky-Watcher F3.4
Camera: ToupTek Astro ATR2600M / ATR2600C
Mount: UMI
Filters: ToupTek Astro 36mm HSO
Processing: Narrowband combination using HSO channel mapping
Total exposure: 20h
Photographer: 原上行川
Telescope: Askar SQA55
Camera: ToupTek Astro ATR2600M
Mount: iOptron HAE16C
Filters: ToupTek Astro 36mm HSO
Astrophotography wireless controller: StellaVita
Integration: Hα: 71 ; OIII: 63 ; SII: 49
Total exposure: 15h
Photographer: Yahushua
Telescope: Askar 130HNT28-AL
Camera: ToupTek Astro ATR585M
Mount: iOptron CEM26
Guide camera: G3M2210M
Filters: ToupTek Astro 1.25” HSO
Total exposure: 7h
Photographer: voice
Telescope: Sky-Watcher
Camera: ASI2600M
Filters: ToupTek Astro 2” HSO
Mount: UMi 17
Integration: Hα: 36 × 600s ; SII: 36 × 600s ; OIII: 36 × 600s
Total exposure: 18h
What are narrowband filters used for in astrophotography?
Narrowband filters isolate specific emission lines such as Hα, [OIII] and [SII] while suppressing much of the unwanted background light. They are especially useful for imaging emission nebulae and building SHO narrowband images.
What is an SHO filter set?
An SHO set contains SII, Hα and OIII narrowband filters. Each filter records a different emission line, and the three channels can be combined during image processing for SHO color mapping.
Which narrowband filter size should I choose?
Use 1.25-inch filters for cameras with a 1-inch or smaller sensor, 36mm filters for APS-C and smaller sensors, and 2-inch filters for full-frame and smaller sensors.
- 36mm unframed filters: Special coating eliminates ghosting. To install, align the side with the inward-extending black ring toward the telescope for instant orientation and improved convenience.
- 1.25" & 2" filters: Special coating removes front/back orientation concerns—simply screw in for fast, tool-free installation.
- Quality Assurance Inspection: Each filter undergoes pre-delivery spectral testing and rigorous screening to guarantee consistent optical performance.
- After-sales Policy: Includes a two-year warranty covering manufacturing defects, plus professional technical support and usage guidance.
- For assistance, please contact our support team:
https://touptek-astro.com/supports
- Color Variation: Filter coating colors may appear different under varying lighting conditions and viewing angles—this is normal optical behavior.
- Product Improvements: We continually optimize our products, which may result in minor specification and appearance updates. Specifications are subject to change without notice. Please refer to the physical product for final details.
