Archive for category Astrophotography
Moon Mosaic Application with Claude Code
Posted by jmeriaux in Astrophotography, Moon on September 19, 2026
A lunar mosaic needs the same finishing work as a solar one — joining overlapping frames, then deconvolution, sharpening, and dealing with the high dynamic range between the sunlit surface and the terminator. I used to do all of that by hand in Photoshop.
I built MoonMosaic with Claude Code — similarly to SunMosaic. It joins 2 to 6 overlapping frames into one mosaic, or takes a single shot as it is, then offers the finishing steps a lunar image usually needs: deconvolution, sharpening, flip, rotation, and a terminator layer that tames the Moon’s dynamic range.
In my workflow, each frame going into a mosaic is pre-processed the same way as for the Sun: a 16-bit video of the region, stacked in AutoStakkert!4 with 500 final frames, using the Laplace quality estimator and a grid of alignment points over the surface — saved as a 16-bit TIFF. Those TIFFs are what MoonMosaic takes in.
Layers and a mask are created behind the scenes, so that the terminator features can be processed in a separate layer. The final output (a TIFF file) can be opened in Affinity Photo, or any other tool supporting the TIFF format and TIFF layers, for additional processing.
It’s open source and posted on github.com/m42cococa/MoonMosaic. A ready-to-run .dmg installer is available here — Apple Silicon Macs only. It also runs as a local browser app or from the command line.
Sun Mosaic Application with Claude Code
Posted by jmeriaux in Astrophotography, Sun on September 13, 2026
I used to rely on Photoshop to create Sun mosaics — building the layers and masks needed for H-alpha processing, a multi-step process.
I built SunMosaic, an application for processing solar mosaics, using Claude Code — and Photoshop is no longer part of my solar imaging pipeline. Importantly, it doesn’t just assemble the panels into a mosaic: it also separates the solar disc from the surrounding prominences into their own layers and a mask, so each can be processed independently — which is what makes the rest of the workflow, below, possible.
I would like to share it “as is” as an open source project: github.com/m42cococa/SunMosaic.
A ready-to-run .dmg installer is available here — Apple Silicon Macs only. It also runs as a local browser app (Streamlit) or from the command line for anyone who wants to script it.
How the pipeline works
Each panel of a mosaic starts life as a 16-bit video captured through the rig. From there:
- Stack each panel with AutoStakkert!4 to produce a sharpened per-panel TIFF.
- Feed the stacked panels into SunMosaic, which detects the solar limb on each frame, cross-correlates the overlapping regions, solves the global alignment, corrects for the uneven brightness typical of H-alpha etalon imaging, and blends the panels into a single mosaic. Beyond the flattened image, it also generates separate layers and a mask that isolate the solar disc from the surrounding prominences, so each part of the image can be adjusted independently downstream.
- Finish the mosaic in Affinity Photo 2 (free software now), using the disc and prominence layers and mask SunMosaic exports to fine-tune each independently before flattening the final image.
Example: September 8, 2026 mosaic
Here’s a mosaic captured on September 8, 2026 at 20:38 UTC, built from 4 panels stacked from about 500 frames each, using the same rig described in my previous post — William Optics 60mm refractor, Daystar Quark H-alpha filter, and ZWO ASI 432MM camera.
Another example: September 13, 2026 mosaic
Captured on September 13, 2026 at 20:29 UTC, same rig and pipeline.
The Apennines Mountains
Posted by jmeriaux in Astrophotography, Moon on May 25, 2026
Taken using my 150mm Rumak-Maksutov and the same ZWO ASI 432MM camera I used for the previous Sun picture.
I added a 2x Televue Barlow in the imaging train.
Taken on 2026 May 25th at 4:12 UTC.
It was processed in Photoshop from two pictures, each stacked from about 500 frames.
About the Image
This view looks across the eastern shore of Mare Imbrium. The Montes Apenninus — the lunar Apennines — form the rugged range sweeping across the lower half of the frame, marking the southeastern border of the mare. A few landmarks worth picking out:
- Archimedes — the large, smooth-floored crater near the centre, at the northwestern foot of the Apennines.
- Aristillus and Autolycus — the pair just above and to the right of Archimedes, with Aristillus showing bright ejecta and central peaks.
- Cassini — above and right of centre, recognisable by the smaller crater sitting on its flooded floor.
- Plato — the dark-floored crater at upper left, on the northern shore beside the terminator.
- Vallis Alpes (the Alpine Valley) — the straight cleft slicing through the Montes Alpes near the top.
- Aristoteles and Eudoxus — the prominent crater pair along the right edge.
Sun Observation – 2026-05-24
Posted by jmeriaux in Astrophotography, Sun on May 25, 2026
Taken at 20:05 UTC on 24th of May 2026.
Captured in H-Alpha using my William Optics 60mm refractor with a Daystar Quark filter and a ZWO ASI 432MM camera. The final image is a mosaic of 4 panels, each stacked from about 500 frames.
North America & Pelican Nebulas
Posted by jmeriaux in Astrophotography, Deep sky objects on October 7, 2024
ZWO Redcat 70mm with Radian quad-band filter and MC 2600 Asi Camera on 2nd of September 2024 – Concord CA
- 26 light frame 40 sec
- 8 dark frame 40 sec
- 17 Bias
- 30 Flat frame 1 sec 2 sec 3 sec
- Bin 1×1
The stacking was done using the ZWO stacking software and additional processing was done with PixInsights.
5th of June 2012 Venus Transit
Posted by jmeriaux in Astrophotography, Planets, Sun, Uncategorized on September 3, 2018
The next Venus transit will be in December 2117… I took these pictures with my Coronado 90mm H-Alpha telescope in June 2012. You can get more information on this historical Venus 2012 transit on the Nasa web site.
Below is a picture of the first contact on the 5th of June 2012, at 3:07 PM PDT at San Bruno CA. The disk of Venus can be guessed in the mid-section.
A non-processed movie of the entry of Venus can be see below. It shows the first minute of the entry of the disc in front of the Sun.
The next picture was taken at 3:22 PM PDT. The Venus’ disk is clearly visible at this time. There is a large solar filament on the top of the image.
Later at 5:59PM PDT Venus is making its progression on the Solar disc. Solar spots can be seen on the left side of the Venus’ disc.
Monkey Nebula (NGC 2174) with SVR90T in Narrow band
Posted by jmeriaux in Astrophotography, Deep sky objects on March 9, 2011
Location: San Bruno, CA
Telescope: Stellarvue SVR 90T with Stellarvue Field flattener on Takahashi NJP-Z Mount
Camera: Qhy9 CCD with Astronomik H-Alpha 12nm Filter and O-III 12nm Filter
The color picture is a “HOO” Narrowband picture:
- H-Alpha: red channel – 16 exposures of 480secs.
- O-III: green and blue channel – 21 exposures of 480 secs.
On the left, the H-Alpha image, on the right the HOO composite image. Note the Monkey nebula emits mainly in H-Alpha only the central parts of the nebula glows in the OIII band.
