Michael‘s Astrophoto Blog

Using the L-eXtreme dual narrowband filter allows taking quite impressive pictures of various nebulae. However, it will create quite unnaturally looking star colors and will filter out features of the object that are not particularly emitting the spectral lines of Ha or OIII.   Some objects, due to their physical structure, look quite different in the narrowband than in images taken over the full RGB continuum. The crab nebula M1 is a good example for this. M1 the crab nebula in HaOIII, 40x90sec C9.25 on EQ6-R Pro, ASI294MC PRO, L-eXtreme M1 the crab nebula unfiltered RGB image, 40x60sec, C 9 .25 on EQ6-R Pro, ASI 294MC Pro It is interesting to look at and compare these pictures individually.    However, I wanted to try combining them in a meaningful way. Basically I had five different "channels" - red, green, blue, Ha and OIII and was looking for good ways to compose an image from that. There are several ways for doing that, some more flexible than others. I ended up using A

When taking my first pictures with the L-eXtrem dual narrowband filter I was quite pleased with the results I was able to get. This filter passes only the Wavelengths of the Ha and O III spectral lines that are very prominent in may nebulae. It turns out being a good tool to expand imaging time beyond just the moonless nights.  Core of M42 Orion Nebula im HaOIII, 50x10sec C9.25 on EQ6-R Pro, ASI294MC PRO, Reducer 1/6.3, L-eXtreme IC405 in HaOIII, 30x300s,  C9.25 on EQ6-R Pro, ASI294MC PRO, Reducer 1/6.3, L-eXtreme IC433 in HaOIII, 40x120sec C9.25 on EQ6-R Pro, Reducer 1/6.3, L-eXtreme Filter Detail of NGC2246, Rosette Nebula in HaOIII, 30x90sec C9.25 on EQ6-R Pro, ASI294MC PRO, Reducer 1/6.3, L-eXtreme However, I noticed that particularly the pictures that were taken with both the reducer/corrector and the filter showed some light color fringe around the stars. I assume that something in the geometry of the imaging train wasn’t quite optimal. As I didn’t have to many options right away