10/10/2025 Infrequently Imaged Globulars + Helix Nebula (NGC7293)

The original plan for the night was to image infrequently or never imaged globular clusters that hover low near the southern horizon. Near the zenith 30 to 60s exposures are used where I do imaging.  With skyglow from surrounding towns near the horizon limited exposures to about 15s. Unexpected intrusions from trees to the south left some planned targets for another time. NGC7293 was not part of this night's plan but made for a fun and revealing experiment with the GraXpert app. Usual setup: Celestron 8/AVX, Starizona Night Owl 0.4X Focal Reducer, ZWO ASI294MC Pro. Exposures: 30x15s subframes. Post processing: stack averaging with Autostakkert!4. Stretching and gradient reduction with GraXpert 3.02, Final processing: Paintshop Pro 2021. 

Messier 19

Messier 22

Messier 28

Messier 54

NGC 6712

NGC7293 (Helix Nebula)

A Bit on GraXpert A.I.

The GraXpert app uses sophisticated gradient removal algorithms including Kriging, Splines, RBF and a recently introduced A.I. algorithm. The non-A.I. routines require an editable sampling matrix be applied to the image. For the A.I algorithm you need only load the image, set the stretch value then run it. However, there is a smoothing parameter that can be set to value between 0.0 and 1.0. It's affect on an image can be dramatic and unlike the non-A.I. algorithms there's no sampling matrix or settings to play with to try to improve your image. The above images were all processed with RBF I most frequently use in linear mode. Where needed I tweak the sampling matrix. Below are three images processed with GraXpert A.I. mode using 0.0, 0.5 and 1.0 smoothing settings. I'll stick with RBF or Kriging.

 

0.0 

0.5

1.00

Recovery from problematic experiment.

Recently I experimented with acquiring light frames sans dark frames in SharpCap. The result was ugly.  For reasons still a mystery to this imager Autostakkert! could not correct for vignetting when the session flat frames were applied. 

Autostakkert does offer the option to apply the dark frame during stacking but this did not work either. Hmm? Astro-imagers often promote DeepSkyStacker for stack averaging astro images; so I gave it a try. DeepSkyStacker rejected my .png flat frame as an unknown format  and rejected it's converted to .tif format as the wrong color. These files are readily accepted by Autostakkert! which was used to stack average the images without using the flat.  

Thanks to careful some cropping in GraXpert gradient remove software, the  descent images below were resulted after post processing in PaintShop Pro 2021 

IC 5146

NGC 7380

NGC 7538

NGC 7635

Sharpless 112

Setup: 

Celestron 8 AVX, Starizona NightOwl 0.4X focal reducer, ASI294MC Pro,      Orion Mini Autoguider.

Imaging: 

30x60s subframes, -10C, 

Processing: 

Autostakkert!(stack averaging), GraXpert (stretching/gradient removal), Paintshop Pro 2021                  

08/31/2025: IC 4665, IC 5146, Messier 13, NGC 7635, Sharpless 140, Sharpless 142, Sharpless 155

Celestron 8/AVX, Starizona Night Owl 0.4X Focal Reducer, ASI294MC Pro Orion Mini Autoguider. Nebulae: 30x60s subs, IC4665: 30x15s subs, Messier 13: 30x30s subs. Stack averaging with Autostakkert! Stretching and gradient reduction with GraXpert. Post processing with Paintshop Pro 2021. 

IC 4665

IC 5146 (Cocoon Nebula)

Messier 13 (Hercules Globular Cluster)

NGC7635 (Bubble Nebula)

Sharpless 140

Sharpless 142

Sharpless 155

08/26/2025 : M29, NGC6633, NGC6882, Sharpless 112

SETUP: Celestron 8 / AVX, Starizona Night Owl 0.4X Focal Reducer, ASI294MC Pro. EXPOSURES: see image. Processing: Autostakkert! (stack averaging), GraXpert (stretching / gradient removal). PaintShop Pro (post processing).

Messier 29 (30x15s, -10C)

NGC6633 (15x30s, -10C)

NGC 6882 (30x15s,-10C)

Sharpless 112(60x30s)

07/21/2025: Messier 8, Messier 13, NGC6857

Along with five of my favorite targets M8 and M13 this was my first attempt at imaging NGC6857. M16, M17 and M20 were imaged on 7/19/2025. I plan to revisit NGC6857 to see if I can pull out any more nebulosity. Usual Setup: Celestron 8/AVX, Starizona Night Owl 0.4X Focal Reducer, ASI294MC Pro

Messier 8 (Lagoon Nebula, 60x15s, -10C)

Messier 13 (Hercules Globular Cluster, 60x15s, -10C)

NGC6857(60x30s, -10)

 The following DSOs were imaged 07/19/2025

Messier 16 (Eagle Nebula, 30x15s -10C)

Messier 17 (Omega Nebula/Swan Nebula, 30x15s,-10C)

Messier 20 (Trifid Nebula, 30x15s, -10C)

06/24/2025 Globular Clusters

Setup: Celestron 8/AVX, Starizona Night Owl 0.4X Focal Reducer, ASI294MC Pro. Acquisition and Processing: All objects imaged with 30x30s subs, stack averaged with Autostakkert!, gradient reduction via GraXpert, post processing with PaintShop Pro. 

Messier 3

Messier 5

Messier 10

Messier 12

Messier 53

Messier 13

New Laptop and Orion Magnificent Mini Autoguider. Phew!

It's been a while since I posted. Increased age related sensitivity to winter temps and a bit of laziness around imaging galaxies during galaxy season is partly to blame. I'll do better next fall and winter. Also my aging Acer laptop while usable needs a new keyboard which, according to a local tech guy cannot be replaced. As a stop gap I acquired a $10 Bluetooth keyboard while shopping for a new computer. Also, the Acer is incompatible with Windows 11. 

After some research I opted for a Dell Inspiron 2 in 1 driven by an AMD Ryzen 7 8840Hs at 3.30 Ghz. It shows when in the time it takes to stack lunar images which is an order magnitude faster than the Acer it replaces. For the most part I'm no fan of Windows 11's look and feel or Microsoft's pushing and nudging users towards the Edge browser or obnoxious OneDrive. OneDrive almost caused the loss of my years of SharpCap images. Fortunately there are numerous tipsters providing advice on how to make Win11 less annoying. 

So why the Phew!? When it came time to install the auto-guider software I realized I didn't have the drivers for the Orion Autoguider. As you're likely aware Orion went out of business and PhD2 does not include the drivers. Well, much thanks to someone going by italic posting on Cloudynights  the drivers and installation software can be downloaded from here on archive.org. 

Over the last couple of nights I revisited some of my favorite targets, globular clusters, to give the Orion Autoguider a workout. With the current settings performance has been excellent. 

Setup: Celestron 8/AVX, Starizona 0.4x NightOwl FR, ASI294MC Pro, Orion Mini Autoguider. Imaging: SharpCap pro,  30x30s, 0C, 120 gain. Processing: Autostakkert! (stack averaging), GraXpert (stretching/gradient reduction), Paintshop Pro(image touchup)

Messier 13 (Hercules Cluster)

Messier 3

Messier 5

Messier 10

Messier 12

Messier 53

NGC2359 Thor's Helmet

 

NGC2359 (Thor's Helmet)

Between the trees in front of my terrace and the middle support beam I'm only afforded a 120 min window for imaging an object at the altitude of NGC2359. System consisted of Celestron 8 SCT AVX, Starizona NightOwl 0.4X reducer/corrector, ZWO ASI294MC Pro. 

Things get interesting with gradient removal. My area is heavily light polluted and since I only use a broadband light pollution filter the full image suffers from a halo near the outer edges. The image is cropped but still suffered from some haloing.  

GraXpert offers a number of gradient removal options including an AI version. RBF with thin_plate worked best for reducing the background gradient. The others produced various artifacts including some very dark splotch like areas adjacent to the nebula. Post processing with PaintShop Pro 2021. 

Open Clusters: M34, NGC457, NGC869, NGC1342, NC1528, NGC1545

Clear night, near full moon high to the east, so why not image a few open clusters. All were imaged with 30x15s subframes. Configuration: Celestron 8, Starizona Night Owl F/4 focal reducer/corrector, ASI294MC Pro. Stack averaged with Autostakkert 3, gradient removal with GraXpert, post processing with Paintshop Pro 2021. 

M34

NGC457(Owl Cluster)

NGC869

NGC957    

NGC1342

NGC1528

NGC1545