Hi All. Looking for a 2" H-Beta filter. ETA: for visual use, not photography, so around 8 to 12 nm bandpass.
Sought-after brands:
* Lumicon
* Orion
* Astronomik
* Televue
Not-sought-after brands, because of these opinions:
* Explore Scientific. Too much OIII in their Hb.
* Optolong. Bandwidth too wide - lots of background noise.
* Thousand Oaks - reputation of sub-standard quality control for this item.
Anything else: worth asking.
