Celestial hemisphere:  Northern  ·  Constellation: Gemini (Gem)
Getting plate-solving status, please wait...
Sh2-274, Medusa Nebula, HαRGB, 24 Feb 2015 + 1 Jan 2016, David Dearden
Sh2-274, Medusa Nebula, HαRGB, 24 Feb 2015 + 1 Jan 2016
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Sh2-274, Medusa Nebula, HαRGB, 24 Feb 2015 + 1 Jan 2016

Equipment

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Acquisition details

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Description

RGB:

My first success with Sequence Generator Pro. Conditions were terrible tonight: lots of gusty wind and poor seeing such as we don't usually have in Utah. With my old mount I would not have even tried to image, but the EQ-6 is so much more stable I thought I'd give it a try, although as I mentioned the main purpose of this session was to get SGP working. The plate solving capabilities of SGP are marvelous, although I did have a few problems wherein it tried to use hot pixels and solve on them. The automated meridian flipping is likewise marvelous. I performed it a couple of times, once with a test target and then with this one. I don't have the automated focusing working yet. Some of that was because the air was so unstable it was difficult to get a focus even manually, and some was because I'm using an Orion Accufocus, a relative focuser with a driver that fakes an absolute focuser. Something went wrong with the session after the meridian flip and SGP crashed, so I got less data than I wanted. I think it may have been a bad interaction between Cartes du Ciel and SGP. I had all kinds of problems deBayering the images collected by SGP. Trying to use them directly in Nebulosity led to terrible horizontal banding issues. Eventually I found that Nebulosity puts the x- and y-Bayer offsets in the FITS header (1 and 3, respectively), and the Nebulosity 4 manual has recommended deBayer matrix settings for Sony sensors (and it saves them from one session to the next!). Using those did the trick. More learning and testing is needed. I ought to combine this with my Hα from last year.

Date: 1 Jan 2016

Subject: Sh2-274, Medusa Nebula

Scope: AT8IN

Filter: Baader UHC-S

Mount: EQ-6 (EQMOD)

Guiding: Orion ST-80 + DSI Ic + PHD 2.5.0.9 (Win 7 ASCOM)

Camera: DSI IIc, no chiller CCD -10 °C

Acquisition: Sequence Generator Pro with Nebulosity 4.0.4 ASCOM camera driver

Exposure: 13x600 s

Stacking: Neb 4, bad pixel map, bias included, 33 flats, match histograms, manual demosaic & square, trans+rot align, Nebulosity 40-60tile stack.

Processing: StarTools 1.4.305: Crop; Wipe; Develop: 80.69%; HDR: Optimize; Color:Scientific, 150% sat; Deconvolute: 3.0 pix; Life: Moderate; Track: Smoothness 88%, 4.5 pix; Magic: shrink 2 pix; Photoshop CS6 + Astronomy Tools: deep space noise reduction; increase star color; make stars smaller; Levels; Astroframe.

Hα:

Date: 24 Feb 2015

Subject: Sh2-274, Medusa Nebula (planetary)

Scope: Astrotech AT8IN+High Point Scientific Coma Corrector+Antares 0.5x focal reducer (oops!)

Filter: Baader UHC-S

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.4.1 (Win 7 ASCOM)

Camera: DSI IIc no cooling (about 0 °C)

Acquisition: Nebulosity 3.3.2, no dither

Exposure: 15x600 s

Stacking: Neb 3.3.2, bad pixel map, bias included, no flats, extract R, histogram match, deBayer & square, trans+rot align, 1.5 σ combine.

Processing: StarTools 1.3.5.289 Crop; Develop: 80.91%; HDRptimize; Deconvolute 3.7 pix; Track 4.2 pix; Magic:Shrink 1 pix; Wipe. Photoshop CC 2014 + Carboni Astronomy Tools Hα false color black space; Astroframe

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Sh2-274, Medusa Nebula, HαRGB, 24 Feb 2015 + 1 Jan 2016, David Dearden