Celestial hemisphere:  Northern  ·  Constellation: Orion (Ori)  ·  Contains:  Sh2-261
Getting plate-solving status, please wait...
Sh2-261, Lower's Nebula, HαRRGB, 17 Nov 2018, David Dearden
Powered byPixInsight

Sh2-261, Lower's Nebula, HαRRGB, 17 Nov 2018

Getting plate-solving status, please wait...
Sh2-261, Lower's Nebula, HαRRGB, 17 Nov 2018, David Dearden
Powered byPixInsight

Sh2-261, Lower's Nebula, HαRRGB, 17 Nov 2018

Equipment

Loading...

Acquisition details

Loading...

Description

This image came at the end of a string of clear nights in November; I haven’t had a string like it since. I’m surprised this object isn’t imaged more. It benefits greatly from the Hα filter as the nebula doesn’t show up very well in the straight RGB.

Date: 17 Nov 2018

Subject: Sh2-261, Lower’s Nebula

Scope: AT8IN+High Point Scientific Coma Corrector

Filters: ZWO 31 mm diameter unmounted 7 nm Hα, R, G, B

Mount: EQ-6 (EQMOD 2.000j)+PEC

Guiding: Orion Thin Off-axis Guider + DSI IIc +PHD 2.6.5 (Win 10 ASCOM)

Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21

Acquisition: Sequence Generator Pro 3.0.3.140

Exposure: 36x300 Hα, 12x300 R, 12x300 G, & 5x300 B

Stacking: Deep Sky Stacker 4.1.1 (64-bit) dark+flat (no bias), κ-σ stacking with κ = 1.5.

Processing: StarTools 1.4.332: Software binned all subs 2x2. Vignette wiped the Hα, color & vignette wiped the RGB, stretched, and HDR optimized. Deconvoluted (3 pixels) and untrack denoised the Hα and RGB. Used Photoshop to create HαR as 20% R 80% Hα, and used this to replace the R layer in the RGB. Used HαR as luminance (Starizona Method 1) or used HαRGB (blurred) with Hα as luminance (Starizona Method 2). In both cases, used curves to bring up the color layer and to decrease the luminance layer. Decided I really like the star field but wanted to keep the nebula strong, so combined the Method 1 and Method 2 images using “lighter color.” Finally increased the saturation, AstroFrame.

Comments

Sky plot

Sky plot

Histogram

Sh2-261, Lower's Nebula, HαRRGB, 17 Nov 2018, David Dearden