NGC 4244, the Silver Needle Galaxy, and Getting Better Slowly But Surely

1 May 2014. One of the things I like most about astrophotography is that even though the learning curve is steep (and I like that too), it is easy to see improvement from year to year. I decided to try NGC 4244, the Silver Needle Galaxy, last night.  I’ve only imaged this once before, 2 years ago, and back then I was still using my Meade 4501 4.5” F/8 reflector.  I had sort of resisted going back to this target because it seemed to have little structure and a silver streak in the sky was just not that interesting.  On the other hand, I reasoned there was a good chance I could make significant improvements over the prior image given what I know now, so I decided to give it a shot.  Conditions were excellent: crystal clear skies and no moon with little or no wind.  I used Cor Caroli as my sync star and easily got to this target using the PicGoto.  Guiding started off very well.  The weather is warming up, so the camera sensor started at 13 °C and fell to about 11 °C with no active cooling (I guess I’ll need to start that up soon).  I stopped every hour to refocus using Nebulosity's fine focus feature.  I performed a meridian flip, but my guiding was much worse after the flip; this seems to be a recurring thing.  It was worse on both axes too.  Most of the subframes after the image flip were blurred.  I need to figure out why this is happening; likely it is a balance issue, because I know balance is critical with my mount.

Anyway, here’s the processed image from 2 years ago.  It’s not terrible given my level of skill and extremely inexpensive equipment at the time.

Date: 23 Apr 2012

Subject: NGC 4244, Silver Needle Galaxy

Scope:  Meade 4501, 0.5x Antares telereducer

Filter:  none

Mount: CG-5 (Synta motors)

Guiding: Orion ST80 + 0.5x Antares telereducer + DSI Ic + PHD

Camera: DSI IIc (cooled at 2 A, 3.0 V)

Acquisition: Nebulosity 3.0.3

Exposure: 15 x 300 s

Stacking: Neb 3, bias included, normalize first, align, 1.5 SD stack

Processing: Digital development & levels, unsharp mask in Neb 3, a bit of levels & Astronomy Tools star color enhance in CS5.

And here’s the new image, processed.  Note that the orientation is not the same; the new image is rotated approximately 180° relative to the old one.  The AT8IN is a much better scope than the Meade 4501 I used in the earlier image, my imaging and processing skills have improved, and the software I’m using now (StarTools) has given me big improvements.  In the new image it is possible to see some subtle internal dust lanes in this edge-on spiral galaxy.

Date: 30 Apr 2014

Subject: NGC 4244, Silver Needle Galaxy 

Scope: AT8IN + HPS Coma Corrector

Filter: None

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

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.2.2 (Win 7 ASCOM)

Camera: DSI IIc no chiller T = 11 °C)

Acquisition: Nebulosity 3.2.0, no dither

Exposure: 21 x 600 s

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

Processing: StarTools 1.3.5.279 Crop; Wipe 79%; Develop 79.57%; HDR:Optimize; Color:Scientific, 250% sat.; Develop: 80.11%; Deconvolute 1.7 pix; Life:Moderate; Track RNC 5.15%; Magic:Shrink 1. CS6 Astronomy Tools increase star color; Healing brush; Astro Frame.