Celestial hemisphere:  Northern  ·  Constellation: Coma Berenices (Com)  ·  Contains:  M 98  ·  NGC 4186  ·  NGC 4192
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M98, OSC (UHC-S), 17 Mar 2016, David Dearden
M98, OSC (UHC-S), 17 Mar 2016
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M98, OSC (UHC-S), 17 Mar 2016

Equipment

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Acquisition details

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Description

This was a first-time (for me!) image of M98 as I continue to add to my galaxy collection. It's a good time of year for that. My problems with plate solving persist, so the cause is probably not the number of stars in the field. I also managed to filter out all the hot pixels, so only stars (and galaxy nuclei) were being found as stars by the plate solver. So I'm a little stumped about what is wrong. Fortunately, my initial goto got M98 just barely into the field of view of my imager, so I consider that pretty good and I was able to start imaging fairly quickly. I also continue to have communication problems with my main imager; it just hangs every once in a while and keeps me from getting as much data as I'd like. It's possible my cheap USB hub is causing the issues, although it never used to when I was using Nebulosity alone. I may try the beta version of SGP to see if it is any better, but the long-range solution is to get a better imaging camera. I stretched this image more than usual because I wanted to bring up the faint surrounding galaxies. Again, the image was redder than I wanted so I did some additional red bias reduction; there's still a lot of red. There's also some elongation in RA, reflecting differential flexure. The galaxy cluster in the bottom left, Abell 1499, is reported to be 2 billion light years away; not exactly a member of the Local Group!

Date: 17 Mar 2016

Subject: M 98

Scope: AT8IN + High Point Scientific 2” Coma Corrector

Filter: Baader Planetarium UHC-S

Mount: EQ-6 (EQMOD)

Guiding: Orion ST-80 + Antares 0.5x focal reducer + DSI Ic + PHD 2.6.1.1 (Win 7 ASCOM)

Camera: DSI IIc, no chiller CCD 4 °C

Acquisition: Sequence Generator Pro 2.4.3.25 with Nebulosity 4.0.4 ASCOM camera driver

Exposure: 15x600 s

Stacking: Neb 4, bad pixel map, bias included, 33 flats, CMYG nebula filter, match histograms, trans+rot align, Nebulosity 40-60%tile stack.

Processing: StarTools 1.4.305: Crop; Wipe; Develop: 89.07%; HDRptimize; Color:Scientific, 200% saturation, red bias reduce at 1.32; Deconvolute: 3.1 pix; Track: Smoothness 95%, 6.5 pix; Magic, shrink 1 pix. Photoshop CS6 + Astronomy Tools: Deep space noise reduction; Space noise reduction; Gradient Xterminator; Increase star color; layer-masked local contrast enhance; less crunchy more fuzzy; Astroframe.

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M98, OSC (UHC-S), 17 Mar 2016, David Dearden