Partial Solar Eclipse 2025
Introduction
On 29 March 2025, a partial solar eclipse was seen from Western Europe and Eastern North America. The greatest coverage was over 90%, visible from northeastern Canada just after sunrise. In Groningen, Netherlands, a maximum coverage of about 25% was reached around midday. Cumulus clouds made it difficult to see continuously, but enough images could be captured between the clouds to document the event. Whole-disk images in Ha were taken every 30 seconds during the eclipse, which were used to create a timelapse.
Maximum of the solar eclipse
Composite image of the different stages of the eclipse.
Conditions
Images were taken on 29 March 2025 from a quiet parking lot west of Groningen, The Netherlands, with a clear view of the southern sky. The eclipse started at 11:19:55 and peaked at 24.34% at 12:13:07. It ended at 13:06:59. Passing clouds affected the images, but there were enough clear moments to enjoy this rare event.
The eclipse was visible in Western Europe and North-Eastern America. Maximum coverage in The Netherlands was about 25%, while in some parts of Canada just over 90% of the solar surface was covered. Source: TimeAndDate
Passing clouds affected the images, but there were enough clear moments to enjoy this rare event. Approximately 30% of the images were lost due to clouds.
Equipment
The rig consisted of a Takahashi FOA-60Q telescope, a Lunt LS60FHa front-mounted H𝛼 filter and a Player One Saturn-M SQR camera directly behind the B1200 blocking filter. The native focal length of 900mm in combination with the generous size of the IMX533 sensor in the Saturn-M camera give a perfect field of view to record full disk images.
Telescope
Mount
Camera
Filters
Guiding
Accessoires
Software
Takahashi FOA-60Q, Lunt LS60Ha front mounted H𝛼 filter
Rainbow Astro RST-135E, Gitzo 5-series tripod
Player One Saturn-M SQR uncooled
Lunt B1200 blocking filter
TeleVue Sol-Searcher, Unguided
Apple MacBook Pro M2 Max
MacOS 15.3.2, FireCapture 2.7.15, AutoStakkert!4, PixInsight 1.9.3, Photoshop 24.0.1, Final Cut Pro 11.0.1
Imaging
The setup had been tested recently for some regular solar imaging. It has the perfect proportions for a mobile setup. The whole rig fits in a HPRC5200 hard case, with the tripod in a separate shoulder bag. Setting up is about a 10 minute procedure, including polar alignment and focusing. Focusing was done manually. 20s SER videos were recorded at 40 fps. This created files of around 800 frames each. Gain was set to 125 (HCG mode of the Player One Saturn-M camera) and exposure at 5ms. The Autorun feature in FireCapture was used to collect a 20s recording each half minute. The Autorun was set for 240 recordings, which would cover two hours, more than enough to capture the eclipse from start to end (1h47m).
3008 × 3008 px (9 MP)
900 mm @ f/15
3.78 µm
43' x 43'
Resolution
Focal length
Pixel size
Field of View
System ready to capture as soon as the eclipse started
Processing
The SER videos came in three qualities: completely black, visible sun but with passing clouds, and clear sun. The clear sun videos were automatically analysed in AutoStakkert!. The 100 best frames of roughly 800 total frames were combined into a single stack and exported as TIF file. The passing clouds videos were manually analysed in Autostakkert!. Particularly the image stabilisation was very unpredictable. The stabilisation algorithms could go all over the place and move the solar disk around, resulting in very poor stacks. After a lot of trial and error, the following workflow was applied. If the stacking did not result in anything decent, first ‘surface’ stabilisation was used, rather than ‘planet’. If that did not work out, a manual selection of an anchor point was tried. If that did not work, the stablization algorithm was completely disabled. The AP alignment was now on its own, but given the decent tracking, the outcome often was pretty decent. Finally the maximum number of frames to stack was altered, depending how badly the frames were affected by the clouds. Final stacking numbers ranged from 20-100 frames per stack. The fully black recordings were discarded.
Of the total 234 videos recorded, 52 (22%) were fully black and could not be used. Manual and custom stacking approaches could rescue another 58 (25%), but left 24 (10%) unusable. A total of 158 frames made it eventually into the final timelapse. Unfortunately the missing and poor frames lead to some shaky and flickering video at times. Since the images were all inverted, darker clouds passing actually show up as a somewhat lighter frame.
The next step was to position the images all with the north side up. It was not very difficult to assess what was north, as the visual observation of the eclipse clearly indicated the proper orientation. For the images, acquired both before and after the meridian flip, this was a bit of a puzzle. But by mirroring in the proper direction, and an 18° rotation (all in PixInsight), the images finally ended up in the proper direction. Another step was to align the images. This was done using the Fourier Transformation script (FFRegistration) in PixInsight.
Once all the stacks were produced and properly positioned and aligned, the rest of the processing rather easy. Most was done in PixInsight. In the Solar Toolbox script proper exposures were set. This included black- and whitepoint, fine-tuning of the rim and boosting the prominences. The images were inverted at this stage. Contrast enhancement was done using BlurXTerminator. Colorising was done using CurvesTransformation. Some extra sharpening was applied using LocalHistogramEqualization. All PixInsight processes could be automated using Image- and Process containers.
One drawback of the FFRegistration script is that it creates outputs with different geometry. So whichever tool you look them in to create a timelapse, you will again introduce small alignment issues. The approach taken here was to load them all as layers in Photoshop, with the alignment option on. Crop them all so that no transparent edges were visible anymore. And finally export the frames again as separate JPEGs. The JPEGS were then loaded into Final Cut Pro to create a timelapse, add a title, etc.
Processing workflow (click to enlarge)
In conclusion, while the weather conditions were not optimal, it was possible to capture the partial eclipse of 29 March 2025 and create somewhat of a timelapse video of the event. The next solar eclipse is a total eclipse on 12 August 2026 and is visible from Spain.
This image has been published on Astrobin
