IC405, The “Flaming Star Nebula”

After imaging IC410, the next logical thing to image was its bigger companion, IC405. Known as the Flaming Star Nebula, it’s the other bright nebula within the hexagon of Auriga’s stars. The ripples at right are really nice (easily enhanced with LocalHistogramEqualization), but IC405 lacks the color contrast of IC410. The SII and H-alpha overlap … More IC405, The “Flaming Star Nebula”

Empirical Evidence on Narrowband Filters with a Fast Telephoto Lens

[Updated with charts and 3 nm OIII data, 2 Dec 2020] Fast focal ratios and narrowband filters are known not to mix well. This is because light arriving at a steep angle to a glass filter will have its wavelength shifted. The faster the focal ratio, the steeper the light cone, and thus at some … More Empirical Evidence on Narrowband Filters with a Fast Telephoto Lens