I have been wanting a set of these for a while but did not want to spend the money. Well, Highpoint Scientific had a set of ZWO Ha, OIII and SII narrowband filters on sale and I went for it. Tried out the Ha filter last night on M42 and this is the result. It is 17 images stacked at ISO 3200 with an exposure of 75 seconds each along with 7 darks. Still got a long way to go learning how to use and stack these babies!