Swansea Astronomical Society Blog

Stack of 105 minutes worth of 20s exposures with the Seestar S50 using the official Seestar EQ fluid wedge. Stacked in PixInsight: Processed in PixInsight, GraXpert, Cosmic Clarity and Gimp. Rendered as HOO and RGB.

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The Eagle nebula RGB

The Eagle nebula HOO

Steve Wainwright and Nicola Mackin

posted by astroimager  # 6:24 PM 0 Comments

Trifid nebula (M20): Due to the extremely short night, I was only able to capture 80 minutes of SHO and 72 minutes of LRGB data between ten past midnight and 02:40 this morning before the skies became too bright to continue imaging. This delightful object located in the Scutum-Centaurus arm of the Milky-way is some 4,100 light years distant and is so called due to containing three distinct objects; a star cluster, an emission nebula and a reflection nebula where new stars are being born. The data were acquired with an ASI 533MM Pro camera and filter wheel set attached to a Sky-Watcher Esprit 80 ED triplet refractor fitted with a field flattener. I processed the data as two separate compositions of LRGB and SHO using Pixinsight and then combined them both together as a cropped SHO/LRGB blend comprising the full 2.5 hours of data capture.

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Trifid nebula (M20) SHO RGB stars

M 20 LRGB and SHO RGB stars cropped

M20 LRGB RGB stars

Chris Bowden

posted by astroimager  # 3:44 PM 0 Comments

Stack of 143 Bridge camera images that had been precisely cropped and registered in Nicola's AstroCrop. Stacked in Autostakkert!4, wavelet processed in waveSharp and finished in Gimp.

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The Sun in white light

Steve Wainwright and Nicola Mackin

posted by astroimager  # 9:48 PM 0 Comments

H-alpha with a Coronado Solarmax II 60 BF15 H-alpha scope scope, an SVBONY SC715C OSC CMOS camera and AstroDMx Capture, capturing 2 overlapping RAW 2000-frame SER files. The White light images were capture with a Panasonic Lumix DMC-FZ72, 60x optical zoom Bridge camera through an ICE ND100000 solar filter.

The best 75% of the frames in the SER files were stacked in Autostakkert!4.

The resulting images were wavelet processed in waveSharp. The images were cropped so that any edge artefacts at the edge to be stitched were removed. The two images were then converted to greyscale and stitched in MS ICE.

The bridge camera images were precisely cropped and registered in Nicola's AstroCrop and the best 75% were stacked in Autostakkert!4. The resulting image was wavelet processed in waveSharp.

The H-alpha and White light images were both further processed in Gimp and Photoshop CS2.

The H-alpha image was processed in PixInsight Solar Tool Box and then, indpendently colourised in PI Solar Toolbox and Solar Gun (which colourise for H-alpha in slightly differet ways. The two colourised images were merged in Gimp.

The H-alpha and White light images were blended in Picture Window Pro using shift-rotate-scale. The blended image was then given a gentle processing in PI Solar Toolbox without colourisation.

The White light image was gently colourised in Gimp and the H-alpha/White light blended image was colourised in Gimp to a yellow with a slight reddened Hue to represent a point in the spectrum representing the merge.

The reason for merging a white light image and a H-alpha image of the Sun is that white light shows more of the Sunspots whereas in a H-alpha image, the sunspots are slightly less distinct, particularly the pore components. The merged image shows good detail of all of the chromosphere and photosphere components.

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H-alpha grey scale image

Steve Wainwright and Nicola Mackin 

posted by astroimager  # 4:12 PM 0 Comments

John Beer (SAS) gave an engaging and well illustrated talk on Astrophotography. He dealt with progress through the history of astrophotography from the earliest times with a very local interest through to the present day. John brought some of his own equipment that he was able to use to explain specific points about the equipment. The talk was well received and led to a lively discussion. 

posted by astroimager  # 11:00 PM 0 Comments

Stack of the best 90% of 153 Panasonic Lumix DMC-FZ72, 60x optical zoom Bridge camera images of the Sun through an ICE ND100000 solar filter.

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The Sun in white light

Steve Wainwright and Nicola Mackin

posted by astroimager  # 10:00 PM 0 Comments

I used the PixInsight solar Toolbox process to process; sharpen, change local contrast and colourise a H-alpha solar image.

I then used Solar Gun to add to-scale images onto the image to give true scale to the structures on the Sun.

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Planet-augmented image of the H-alpha Sun

Expanded detail of the appropriate area of the Sun

Using software combinations such as this can be quite useful, using the most useful features of each program.

Steve Wainwright

posted by astroimager  # 3:57 PM 0 Comments

A late afternoon gap in the clouds with a very hazy sky allowed the capture of 153 Panasonic Lumix DMC-FZ72, 60x optical zoom Bridge camera images of the Sun through an ICE ND100000 solar filter. The images were precisely cropped and registered in AstroCrop, wavelet processed in waveSharp and finished in Gimp 2.10. 

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The Sun in white light

Steve Wainwright and Nicola Mackin

posted by astroimager  # 9:12 PM 0 Comments

Sylvain Weiller's 'Solar Gun' software can be used to colourise solar images and also to place to-scale images of Jupiter and or Earth on the colourised image.

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Solar Gun in action

Colourised image of the Sun in H-alpha light

Full details and all of the images can be seen in my article HERE.

Steve Wainwright

posted by astroimager  # 2:02 PM 0 Comments

I reprocessed my IC405 image from Portugal last winter. This time I used the Foraxx palate. Though I did some colour masking and boosted the red nebula area. I've also managed to bring out some of the background nebulosity.

96 x 300 sec exposures with the ASI533 OSC on my 70mm refractor using Altairastro 4nm duoband filters, HaOiii and SiiOiii.

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IC405, The Flaming star nebula

Anne Startup

posted by astroimager  # 2:12 PM 0 Comments

90% waxing Moon: In the early hours of the 8th June, with the moon low down on the horizon partly obscured by cloud, I used my ASI533MM Pro camera fitted with a Meade Moon filter attached to a Sky-Watcher Esprit 80 ED triplet refractor fitted with a field flattener, to take a one minute SER of the Moon using Astro DMx Capture. Some 15% of the 628 frames were then stacked in Autostakkert!4, wavelet processed in Registax and finished off in Adobe Photoshop 2025 to provide the correct orientation for the moon.

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The Butterfly Cluster (M6): Under poor sky conditions, and with a vantage point partly obscured by grass foliage, I was able to gather just a small amount of LRGB data of this open cluster lying low down in the murk in the constellation of Scorpio. Using my ASI533MM Pro camera and mono filter wheel set attached to a Sky-Watcher Esprit 80 ED triplet refractor fitted with a field flattener, I targeted M6 that was located just a few degrees above the horizon. Due to the grass foliage completely blocking the view of the guide camera, I was only able to shoot 5 x 30s unguided subs on each channel before losing the target completely in the foliage and the murk. I attempted to stack the data in Pixinsight, but due to poor image quality, could only integrate the red and luminance data sets which I merged together and processed as a mono image, having first removed the background artefacts using StarXterminator. I then converted the best single 30s green and blue subs into Tiffs using DSS and then star aligned them with the red and luminance data sets in Pixinsight where I was then able to crop the data and further process it using gradient correction, BlurXterminator, SPCC and StarXterminator to leave an image of just the stars, which I then completed as an LRGB image comprising a total integration time of just 6 minutes. The phone and security camera montage shows the state of sky which appeared to contain possible volcanic dust from recent worldwide eruptions and the low angle the scope was pointed at to acquire the images from the objects low down in the SSW sky. I annotated the wide field mono image in Pixinsight that showed the rich star field in this section of sky proving that even with challenging conditions it is still possible to achieve reasonable imaging results using a range of processing techniques.

Chris Bowden

posted by astroimager  # 6:04 PM 0 Comments

This will be my last go at correcting the stars on the Seestar S50 image that had some star trailing that produced horizontally oval stars. This time I used all of the 2h worth of 30s data for the nebula from which I removed the stars. Then I used the stars from an image integrated from the best 21 minutes worth of 30s exposures which had no, or very little elongation; then I corrected these stars by 1 pixel using a method I have described in workflow 3. Then I added these stars back to the 2h worth of nebulosity. I am satisfied with the result. For my next EQ Seestar S50 experiment, I shall use 20s exposures initially as well as the official Seestar fluid head wedge.

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Final stars-corrected Seestar S50 image of the Eagle nebula

Steve Wainwright 

posted by astroimager  # 1:32 PM 0 Comments

I have written three detailed blog articles explaining two distinct but related Gimp workflows that, in addition to the use of other software, enables the drastic improvement of elongated stars in astronomical images.

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An animation showing before and after star repair

Workflow 2

Workflow 1

It is hoped that the techniques and ideas introduced here will prove to be useful to astro-imagers.

Steve Wainwright

posted by astroimager  # 10:14 PM 0 Comments

The Sun in white light. Stack of 152 bridge camera fitted with an ICE solar filter images. The images were cropped and registered in Nicola's AstroCrop, stacked in Autostakkert!4, wavelet processed in waveSharp and finished in Gimp A blend of the white light with the H-alpha image was made using Picture Window Pro 8. 

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The Bridge Camera attached to a Manfrotto tripod fitted with a fluid head

White light solar image

H-alpha and White light image blend Mono

posted by astroimager  # 5:02 PM 0 Comments

My image of the Scutum Star Cloud taken with my Rokinon 135mm prime lens mounted on my 1300D DSLR Canon camera and mounted on my Star Adventure 2i pro tracking mount.  MY settings were 35s and 800ISO. I captured 80 images,  30 flat frames and 25 dark frames. All were stacked in Sequator and processed in Siril and Gimp 2.10.  I used an intervalometer to control the camera, and a Bahtinov mask to focus on a bright star. 

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The Scutum Star Cloud

Chris Playle

posted by astroimager  # 9:22 AM 0 Comments

The Sun today in H-alpha light. A 2500-frame SER file was captured by AstroDMx capture using a Coronado II 60 BF15 H-alpha scope and an Altair 678M camera. The best 60% of the frames in the SER file were stacked in Autostakkert!4, wavelet processed in waveSharp, and further processed in PixInsight, Photoshop CS2 and Gimp.

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H-alpha light monochrome

H-alpha colourised

Steve Wainwright and Nicola Mackin

posted by astroimager  # 6:28 PM 0 Comments

37.5% waxing crescent Moon: - captured during partially clear skies on the evening of the 1st June -  20% of 2,111 frames captured in Astro DMx Capture, stacked in Autostakkert4 using 1.5 x drizzle integration, wavelet processed in Registax and finished off in Adobe Photoshop 2025.

The Spindle Galaxy (M102): 132 minutes of LRGB data taken with an ASI 533MM Pro camera and mono filter wheel set attached to a Sky-Watcher Esprit 80ED triplet refractor fitted with a field flattener. Data integrated and processed in Pixinsight. M102 is an edge on lenticular galaxy which lies in Draco at a distance of 50 million light years.

Chris Bowden

posted by astroimager  # 6:20 PM 0 Comments

An ASI 533MM pro camera was used with a Meade Moon filter attached to a Sky-Watcher 80 Esprit fitted with a field flattener and Astro DMx Capture was used to take a one minute SER file. Some 30% of the 325 frame SER were stacked in Autostakkert!4 as Tiffs, then wavelet processed in Registax and completed in Adobe Photoshop 2025.

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 28% crescent Moon: 

Chris Bowden

posted by astroimager  # 1:23 PM 0 Comments

I had sparse data on the bottom part of this object, but as I hadn't imaged it before, I was keen to see what a 2 pane vertical mosaic taken with the S-W 80 Esprit and ASI 533 would look like. The rest of the RGB run was too badly affected by cloud to make a colour image, but this was just 16 mins of luminance data on the top bit and 20 mins on the bottom imaged through cloud. Despite the small data set I was quite pleased with how this dark nebula image turned out in Pixinsight. The nebulae are LDN234,204,191 and 190 in Ophiuchus and are always low down from here.

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LDN234,204,191 and 190

Chris Bowden

posted by astroimager  # 5:13 PM 0 Comments

Using Siril scripts for preprocessing and stacking az mosaic data and further processing with Siril, Gimp, GraXpert, Cosmic Clarity and G'MIC qt, I reprocessed some old mosaic data (173 x 10s exposures) on the Orion nebula:

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The Orion and Running man nebulae

Steve Wainwright and Nicola Mackin

posted by astroimager  # 6:18 PM 0 Comments

Click on a sketch to get a closer view

posted by astroimager  # 2:02 PM 0 Comments