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NGC 5985, 5982, 5981, Draco Triplet, OSC, 31 May-1 Jun 2016

Technical card

Resolution: 808x621

Dates: May 31, 2016

Frames: 35x600"

Integration: 5.8 hours

Avg. Moon age: 23.73 days

Avg. Moon phase: 33.46% job: 1106002

RA center: 234.647 degrees

DEC center: 59.339 degrees

Pixel scale: 1.864 arcsec/pixel

Orientation: -177.752 degrees

Field radius: 0.264 degrees

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


Very nice conditions; much better than when I tried two weeks ago and got such poor results I did not post them. I'm also using the Fringe Killer filter rather than the UHC-S. I'm not sure whether it's the darker sky, the filter, or both, but this image turned out WAY better than the attempt 2 weeks ago. Autofocus was still a bit iffy so I shut it off. I had a lot of differential flexure again. Probably the only solution will eventually be to get an off-axis guider setup, but for now I'll just live with it. I especially like the face-on spiral of this group. It almost looks 3-dimensional.

Date: 31 May-1 June 2016
Subject: NGC 5985, 5982, 5981, Draco Triplet
Scope: AT8IN + HPS Coma Corrector
Filter: Baader Planetarium Fringe Killer (UV-IR cut)
Mount: EQ-6 (EQMOD)+PEC
Guiding: Orion ST-80 + Antares 0.5x focal reducer + DSI Ic + PHD (Win 7 ASCOM)
Camera: DSI IIc, no chiller CCD 11 °C
Acquisition: Sequence Generator Pro with Nebulosity 4.0.4 ASCOM camera driver
Exposure: 35x600 s
Stacking: Neb 4, bad pixel map, bias included, 33 flats, match histograms, trans+rot align, Deep Sky Stacker 1.5σ κ-σ stack.
Processing: StarTools 1.4.316: Crop; Wipe; Develop: 80.53%; HDR:Equalize; Color:Scientific, 148% saturation; Deconvolute: 2.5 pix; Track: Smoothness 87%, 6.2 pix; Magic, shrink 1 pix. Photoshop CS6 + Astronomy Tools: Deep space noise reduction; Levels; Levels with layer mask; lncrease star color; Less crunchy more fuzzy with layer mask to preserve dust lane sharpness; Astroframe.



David Dearden

Sky plot

Sky plot


NGC 5985, 5982, 5981, Draco Triplet, OSC, 31 May-1 Jun 2016, David Dearden