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Contains:  M 27, Dumbbell nebula, NGC 6853, The star 14Vul
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M27, Dumbbell Nebula, LRGB, 28-29 Jun 2019, 





    
        

            David Dearden
M27, Dumbbell Nebula, LRGB, 28-29 Jun 2019

M27, Dumbbell Nebula, LRGB, 28-29 Jun 2019

Technical card

Resolution: 2318x1790

Dates:June 28, 2019June 29, 2019

Frames:
ZWO Blue 31 mm: 16x180" (gain: 139.00) -20C bin 1x1
ZWO Green 31 mm: 15x180" (gain: 139.00) -20C bin 1x1
ZWO Luminance 31 mm: 50x180" (gain: 139.00) -20C bin 1x1
ZWO Red 31 mm: 7x180" (gain: 139.00) -20C bin 1x1

Integration: 4.4 hours

Avg. Moon age: 25.53 days

Avg. Moon phase: 17.26%

Bortle Dark-Sky Scale: 5.00

Astrometry.net job: 2769894

RA center: 299.908 degrees

DEC center: 22.745 degrees

Pixel scale: 1.718 arcsec/pixel

Orientation: 176.873 degrees

Field radius: 0.699 degrees

Locations: Mapleton Lateral Observatory, Mapleton, Utah, United States

Data source: Backyard

Description

1227 LY

Between some cloudy weather and a scientific meeting in Italy combined with a lot of walking on cobblestones that did a number on my feet, I have not been out imaging in a while, so I was happy to get a chance to attempt M27 under fairly good conditions. I haven’t tried this target in 4 years or so and thought surely I would get a better image than last time. In that I was a bit disappointed; this is one of the very few cases where I feel like I got more detail in my old image using a DSI IIc than I was able to get using LRGB filters with the ASI1600MM-cool. For some reason I had a lot of trouble focusing with the R filter and got only a few usable subs. Interestingly, most of the detail in the nebula seems to arise from differences in color that did not produce much contrast in the luminance. M27 also seemed to be very bright in G, and I had to back that down a lot in processing. The star field around this nebula is really rich and shows up in this image, and even though it is somewhat lacking in detail the colors are better than I got with the OSC camera (which I find a little ironic).

Date: 28-29 June 2019
Subject: M27, Dumbbell Nebula
Scope: AT8IN+High Point Scientific Coma Corrector
Filters: ZWO 31 mm diameter unmounted 7 nm L, R, G, B
Mount: EQ-6 (EQMOD 2.000j)+PEC
Guiding: Orion Thin Off-axis Guider + ASI120MM-mini +PHD 2.6.6 (Win 10 ASCOM)
Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21
Acquisition: Sequence Generator Pro 3.0.3.198
Exposure: 50x180 L, 7x180 R, 15x180 G, 16x180 B
Stacking: Deep Sky Stacker 4.1.2 (64-bit) dark+flat+bias, κ-σ stacking with κ = 1.5.
Processing: StarTools 1.4.352: Cropped, wiped, developed (holding back a bit), HDR optimized, deconvoluted, and untrack denoised the L data. Combined RGB in StarTools with 2 pixel RGB blur and capping G, cropped, wiped, developed, and used the color module on the RGB data. Untrack denoised. Combined L with RGB version that had G capped to yellow, then layered an RGB with full G on top of that at 50% opacity for just the nebula to try and make its color attractive without messing up the stars. Did a couple of rounds of “Make stars smaller” and a bit of curves. AstroFrame.

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Author

dvdearden
David Dearden
License: None (All rights reserved)
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M27, Dumbbell Nebula, LRGB, 28-29 Jun 2019, 





    
        

            David Dearden