M16, Eagle or Star Queen Nebula, LRGB, 15-20 June 2018 (David Dearden)

M16, Eagle or Star Queen Nebula, LRGB, 15-20 June 2018

My best previous image of this beautiful object left A LOT to be desired, so I thought I’d see what my current level of equipment and expertise could do. I was not disappointed; this turned out way better. I battled problems with my guide camera frequently disconnecting during this acquisition. I think the connector on the old DSI is giving out because wiggling the cables just right was essential and difficult to maintain, so I didn’t get as much luminance as I had planned. It was difficult to add the luminance to the RGB without losing some interesting color gradations, so I did the best I could. I’m intending to add a lot of narrowband data and just wanted LRGB for the stars, but the image turned out well enough I thought I’d post it before I get the rest of the narrowband.

Date: 15-20 Jun 2018

Subject: M16, Eagle or Star Queen Nebula

Scope: AT8IN+High Point Scientific Coma Corrector

Filters: ZWO 31 mm diameter unmounted L, 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 3.0.2.91

Exposure: 51x180 L, 20x180 R, 20x180 G, & 20x180 B

Stacking: Deep Sky Stacker 4.1.1 (64-bit) dark+flat+bias, κ-σ stacking with κ = 1.5.

Processing: StarTools 1.4.332: Combined R, G, and B in StarTools. Binned 2x2, cropped, wiped, developed, HDR, color, deconvolution. Stopped tracking to smooth. Binned L 2x2, cropped, no wipe, and developed followed by HDR. Deconvolution followed by untrack smoothing. Combined L with RGB in Photoshop. Used some layer-masked saturation adjustments, both in the master and in the red channel, to try and retain the red color. A little of Carboni’s Astronomy Tools’ increase star color followed by less crunchy more fuzzy. AstroFrame.

Original
Final
B

B

Description: Per Victor Van Puyenbroeck's suggestion, removed green cast by using a star mask with StarTools' "Cap Green". Also a little different curves on the luminance and color layers to try and bring up the color I see in the pure RGB.

Uploaded: ...

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ZWO ASI1600MM/QHY163M

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Status	Advanced success
Started	...
Astrometry.net job	2114897
PixInsight job	O8WXH142CD311R6OLZGLLW21YKEL8FZ6
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	18h18m45s.56
RA (top/left)	18h16m59s.99
RA (top/right)	18h17m01s.37
RA (bottom/right)	18h20m31s.69
RA (bottom/left)	18h20m29s.14

Dec (center)	-13°48′34″.9
Dec (top/left)	-13°15′37″.4
Dec (top/right)	-14°21′49″.7
Dec (bottom/right)	-14°21′24″.9
Dec (bottom/left)	-13°15′19″.3

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