M31 shot only in Ha and OIII.
Equipment:
- Samyang 135mm f2.0
- Fuji X-T5 unmodified
- Star Adventurer 2i
- STC dual narrowband filter
Images:
- 650x 60s
- ISO 3200
Processing:
- remove green noise
- background extraction
- photometric colour calibration
- BluXTerminator
- NoiseXTerminator (0.4)
- star removal
- GHST
- saturation, blending and final adjustments in Photoshop
This looks amazing! What is the Dual narrowband filter for? And why are they so expensive?
In amateur astrophotography narrowband filters are used to reveal interstellar ionized gas clouds. In this case you can see hydrogen nebulae as red blobs in the spiral arms around M31.
Well for the high cost, apart from producing them is technologically challenging, it is just simple economics. The market for these filters is still small compared to other things, so the price must be higher to compensate production and development.