Milky Way

[Geoff Chaplin]

Ralph, here's mine! 16x6s 20mm lens on A7Riii, flats, darks and biases. I can't remember what the free software was for processing, possible deep sky stacker.

 

[Ralph Turner]

Nice one! Presumably the software aligns the stars anything in the near field is rendered as movement blur. As an indication of how much of a novice astrophotographer I am, I had to look up flats darks and biases…
I have before now contemplated one of those motorised ecliptic mounts to reduce need for high iso but never done anything about it.

 

[Pete Askew]

Very nicely done, Geoff. Nice to see a monochrome sky for a change too.

 

[Geoff Chaplin]

Nice one! Presumably the software aligns the stars anything in the near field is rendered as movement blur. As an indication of how much of a novice astrophotographer I am, I had to look up flats darks and biases…
I have before now contemplated one of those motorised ecliptic mounts to reduce need for high iso but never done anything about it.

Thanks Ralph. Its amazing how much you can get with a standard photo tripod and a digital camera. Using an exposure time of at most 300/focalLength (6s for 50mm, 15s for 20mm) and stacking images. Looking at my notes its seems I used only 4 stacked frames (flats, darks, biases and lights) and then processed in RawTherapee. I can send you my cryptic notes if you like. I wouldn't advise getting an ultra-wide unless you do photo-landscape work (the sky doesnt change much(!) so a handful of photos would cover the entire sky), with a 50mm you can create your own sky map of individual constellations. For any serious work (e.g. time series photometry) or if you want to make pretty pictures of galaxies you need a telescope, serious mount, auto-focus, filter wheel and filters, guide software, chilled monochrome camera, observatory at a high altitude etc - think $100,000 upwards. Or hire time on robotic scopes (many now available for mortals like me).

 

[Ralph Turner]

Thanks Ralph. Its amazing how much you can get with a standard photo tripod and a digital camera. Using an exposure time of at most 300/focalLength (6s for 50mm, 15s for 20mm) and stacking images. Looking at my notes its seems I used only 4 stacked frames (flats, darks, biases and lights) and then processed in RawTherapee. I can send you my cryptic notes if you like. I wouldn't advise getting an ultra-wide unless you do photo-landscape work (the sky doesnt change much(!) so a handful of photos would cover the entire sky), with a 50mm you can create your own sky map of individual constellations. For any serious work (e.g. time series photometry) or if you want to make pretty pictures of galaxies you need a telescope, serious mount, auto-focus, filter wheel and filters, guide software, chilled monochrome camera, observatory at a high altitude etc - think $100,000 upwards. Or hire time on robotic scopes (many now available for mortals like me).

Thanks Geoff, it would be interesting to see how you did it. With mine I was pushing my luck a little with a 30s exposure @24mm. Apart from anything else, looking at the original at 100% the individual points of light are somewhat stretched into short lozenges. Luckily the overall effect isn’t too marred by it.
I do quite like nocturnal landscape approach and there are certainly some fantastic images to be seen online. As for more serious astrophotography, I think my missus might notice the missing hundred grand lol.

 

[Geoff Chaplin]

Thanks Geoff, it would be interesting to see how you did it. With mine I was pushing my luck a little with a 30s exposure @24mm. Apart from anything else, looking at the original at 100% the individual points of light are somewhat stretched into short lozenges. Luckily the overall effect isn’t too marred by it.
I do quite like nocturnal landscape approach and there are certainly some fantastic images to be seen online. As for more serious astrophotography, I think my missus might notice the missing hundred grand lol.

These are the notes. It misses out the production of tiff files in Stacker, its these files that are loaded as lights, flats etc. Good luck!
Before photographing:

1. Shoot a flat frame

2. On the night and once the camera has acclimatised take dark frames



RawTherapee

1. Raw Tab

a. LMMSE 2 enhancement steps (high ISO) or AmaZE

b. click hot and dead pixel filter, ClarkVision uses 143 for Threshold

c. Load dark and flats (only one of each allowed)



2. Transform Tab – all at defaults (auto lens correction)



3. Advanced – none



4. Colour Tab

a. Daylight colour

b. Colour management (last tab) – ClarkVision uses Rec 2020 for working and output (RTv4_Rec2020 used)



5. Detail and Noise reduction

a) Noise reduction – RGB colour space, luminance control Curve (and default settings); Chrominance – Manual and default settings

b) Defringe turned on (default settings)



6. Exposure Settings

a) Clip turned off; highlight reconstruction – colour propagation; exp comp – minus 0.66 to 0.75, increase (?) black point if image is dark to ensure no clipping; tone curve – standard; other settings at default



Copy settings (top right “save profile”) to disk (permanent save)

Apply to other images in the set – file browser, ctrl-c to copy setting to clipboard; select all the other images to apply the settings to and ctrl-v; select all images that the setting should be applied to [including original] and right click one, select send to queue; then click Queue tab, choose output directory and 16 file output and start processing.

 

[Ralph Turner]

Many thanks, Geoff