This is a very easy find because it sits right next to Antares. I decided to try for the interesting shot where both M4 and NGC 6144, two globulars, are visible in the same frame. I thought about trying to fit Antares in too, then thought better of that because Antares would likely bloom very badly in my cameras. My chiller Peltier fried during my last session, so I'm using the other one, which does not match the power supply as well (or at least I have not optimized it). It is a very warm night anyway, but I'm running at 2.5 A, cooling to 18 °C currently.

In the B revision I used 3 layers to increase the color in the background dust and skipped the "less crunchy more fuzzy".

In the C revision I used less stretching, so the background dust shows up less, but the core of M4 looks better and all the stars look a bit smaller.

Date: 10 Jun 2013

Subject: M4 and NGC 6144, paired globular clusters in Scorpius

Scope: Orion ST80+Antares 0.5x telereducer

Filter: Baader Fringe Killer

Mount: CG-5 (Synta motors)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 1.14.2

Camera: DSI IIc (cooled at 2.5 A, 8 V, 17 °C)

Acquisition: Nebulosity 3.1.6

Exposure: 36 x 300 s

Stacking: Neb 3, bad pixel map, bias included, normalize first, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3 Crop; Wipe:Color & Brightness; Develop 90.86%; Contrast; HDR:Reveal Core; Sharpen; Track; Color:Bottom 2.0, Top Full, Sat 600%; Life:Moderate. To a second layer, all the same processes except Develop 92.20%; HDR:Equalize; Sharpen; Color:Bottom 2.0, Top Full, Sat 600%; Magic:Shrink 1 pix; Life:Moderate; Magic:Shrink 16 pix (removing the stars); Denoise twice. CS6+Astronomy Tools: Use the “no stars” layer at 25% transparency on top of the first, “normal” layer, reveal all layer mask and erase the mask over the globulars to preserve detail there; flatten; increase star color; less crunchy more fuzzy in one layer (reveal all mask, cut the mask to keep the globulars sharp); AstroFrame.