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About SpectroSolHub
SpectroSolHub is an image-sharing community for spectroheliograph (SHG) owners. Whether you use a Sol'Ex, an SHG 700, a Sunscan, or even a custom-built SHG, this is the place to share your solar observations with the community.
SpectroSolHub also encourages the use of scientifically valuable metadata. Your images may be used for scientific purposes, contributing to our collective understanding of the Sun.
The platform was created by the author of JSol'Ex, a popular SHG image processing software, out of the frustration of seeing many valuable observations go unshared or lost due to lack of proper cataloging.
In addition to SpectroSolHub, we encourage you to share your observations on the scientific database BASS2000, maintained by the Paris Observatory.
SpectroSolHub also encourages the use of scientifically valuable metadata. Your images may be used for scientific purposes, contributing to our collective understanding of the Sun.
The platform was created by the author of JSol'Ex, a popular SHG image processing software, out of the frustration of seeing many valuable observations go unshared or lost due to lack of proper cataloging.
In addition to SpectroSolHub, we encourage you to share your observations on the scientific database BASS2000, maintained by the Paris Observatory.
Uploading Images
There are two ways to publish your solar observations on SpectroSolHub:
1. Directly from JSol'Ex or INTI (recommended)
These processing tools have a built-in SpectroSolHub publishing feature. After processing your SER file, simply click the "Publish to SpectroSolHub" button. The software will automatically create the observation session, upload all processed images with the correct metadata, spectral line information, and solar geometry. This is by far the easiest and most reliable method.
2. Manual upload
You can also upload images manually from the My Observations page. Create a new observation session, fill in the equipment and spectral line details, then upload JPEG images one by one. Note that manually uploaded images will lack the solar geometry metadata needed for de-rotation animations unless you provide it in the API call.
1. Directly from JSol'Ex or INTI (recommended)
These processing tools have a built-in SpectroSolHub publishing feature. After processing your SER file, simply click the "Publish to SpectroSolHub" button. The software will automatically create the observation session, upload all processed images with the correct metadata, spectral line information, and solar geometry. This is by far the easiest and most reliable method.
2. Manual upload
You can also upload images manually from the My Observations page. Create a new observation session, fill in the equipment and spectral line details, then upload JPEG images one by one. Note that manually uploaded images will lack the solar geometry metadata needed for de-rotation animations unless you provide it in the API call.
Publishing from JSol'Ex is strongly recommended because (support for INTI is coming soon):
- Automatic metadata: solar geometry (disk center, radius, B0, L0, P angles) is computed from the observation date and included automatically. This is required for timelapse animations with de-rotation.
- Consistent titles: the software assigns consistent image titles across sessions (e.g. "Improved image", "Continuum"), which is essential for animation frame matching.
- Batch upload: all processed images from a session are uploaded at once with the correct spectral line, equipment, and observation date.
- Less effort: no need to manually fill in forms or worry about metadata fields.
Each account has a storage quota (both in total bytes and number of images). You can see your current usage on the observation creation and edit pages.
Why quotas? SpectroSolHub is a free, community-driven platform. All server and storage costs are paid out of the developer's own pocket. Storage is the biggest expense: every image is stored in three sizes (original, medium, thumbnail) on cloud object storage, and costs add up quickly as the community grows. Quotas ensure that the platform remains sustainable and fair for everyone.
If you need more storage, please reach out on the Discord server.
Why quotas? SpectroSolHub is a free, community-driven platform. All server and storage costs are paid out of the developer's own pocket. Storage is the biggest expense: every image is stored in three sizes (original, medium, thumbnail) on cloud object storage, and costs add up quickly as the community grows. Quotas ensure that the platform remains sustainable and fair for everyone.
If you need more storage, please reach out on the Discord server.
How Animations Work
SpectroSolHub can generate timelapse animations from solar observations in two modes:
Full animation: when images include solar geometry metadata (provided automatically by JSol'Ex or INTI Partner), the system compensates for solar rotation, interpolates between frames, and supports overlays (coordinate grid, ruler, Earth scale). This is the recommended experience.
Best-effort animation: for manually uploaded images without geometry metadata, a simpler slideshow mode displays frames in sequence without de-rotation or interpolation.
Full animation: when images include solar geometry metadata (provided automatically by JSol'Ex or INTI Partner), the system compensates for solar rotation, interpolates between frames, and supports overlays (coordinate grid, ruler, Earth scale). This is the recommended experience.
Best-effort animation: for manually uploaded images without geometry metadata, a simpler slideshow mode displays frames in sequence without de-rotation or interpolation.
When you open the animation page for an image, the system automatically selects frames using the following process:
- Find candidate images from the same observer with the same spectral line (e.g. H-alpha) within a date range around the reference image.
- Match by image type: images of the same type as the reference are preferred. Compatible types (as defined by the platform) are also accepted as fallbacks.
- Rank candidates: images are scored by match quality (same type, same observer, similar solar radius). The best candidates are automatically selected.
- Generate the animation: selected frames are de-rotated to compensate for solar rotation and interpolated for smooth playback.
For the full animation to work, each image must include solar geometry metadata (disk center, solar radius, B0/L0/P angles). This metadata is automatically provided when you upload from:
- JSol'Ex (available now)
- INTI Partner (coming soon)
For images uploaded manually without solar geometry metadata, SpectroSolHub offers a simplified animation mode:
- Frames are displayed as a slideshow ordered by observation date
- No solar de-rotation (features will drift across the disk)
- No frame interpolation
- No overlay support (grid, ruler, Earth scale)
On the animation page, you can manually adjust the frame selection using the calendar view with month-by-month navigation. Click on any day to add or remove frames, include images from other observers, or filter by title. You can share your custom selection using the share link.
Synoptic Maps (Carrington Planispheres)
A synoptic map (also called a Carrington planisphere) is a rectangular projection of the entire solar surface in Carrington heliographic coordinates. It is built by stitching together narrow strips from daily solar observations over roughly one Carrington rotation (~27.3 days). The horizontal axis represents Carrington longitude (0° on the left, 360° on the right, following the standard convention used by SDO/HMI, GONG and other observatories), and the vertical axis represents heliographic latitude (-90° to +90°).
Synoptic maps are widely used in solar physics to study the distribution and evolution of solar features (active regions, filaments, coronal holes) across the full Sun.
Synoptic maps are widely used in solar physics to study the distribution and evolution of solar features (active regions, filaments, coronal holes) across the full Sun.
To create a synoptic map:
- Open the synoptic map page from any image that has solar geometry metadata (the "Synoptic Map" button on the image detail page).
- Select frames using the calendar. For full 360° coverage, select images spanning about 27 days (one Carrington rotation). Partial coverage is fine too.
- Choose a resolution and whether to normalize brightness across frames (recommended when mixing images from different sessions).
- Click "Generate". The server will project each frame onto the Carrington grid and blend them together. This may take a minute for high-resolution maps.
Each solar observation covers roughly one hemisphere (~180° of longitude). For each frame, the system projects all visible pixels onto the Carrington grid, weighted by proximity to the disk center (pixels near the limb receive less weight). When frames overlap, center-of-disk data is preferred for sharpness.
With daily observations over 27 days, you get full 360° coverage. With fewer days, the map will have gaps (shown in black). The system adapts automatically: when frames are close together, it uses narrow extraction bands for the sharpest result; when frames are far apart, it extends extraction to fill gaps as much as possible.
NOAA Active Regions are fetched from the Solar Region Summary (SRS) and positioned on the map using the frame's own solar ephemeris data for accurate placement.
With daily observations over 27 days, you get full 360° coverage. With fewer days, the map will have gaps (shown in black). The system adapts automatically: when frames are close together, it uses narrow extraction bands for the sharpest result; when frames are far apart, it extends extraction to fill gaps as much as possible.
NOAA Active Regions are fetched from the Solar Region Summary (SRS) and positioned on the map using the frame's own solar ephemeris data for accurate placement.
The map viewer provides interactive overlays:
- Grid: Carrington coordinate grid with longitude (every 10°) and latitude lines. Major lines at 0°/90°/180°/270° longitude and the equator are thicker.
- Active Regions: NOAA active region bounding boxes and labels, positioned from SRS data.
- Color pickers: separate colors for the grid and AR overlays.
- Opacity slider: controls overlay transparency.
Active Region Classification
Sunspot groups (active regions) are catalogued by NOAA and tagged with three properties:
- NOAA number (e.g. AR4055) – a globally unique, sequentially assigned identifier.
- Magnetic classification (Mount Wilson scheme) – describes the complexity of the magnetic field.
- Morphological classification (McIntosh / Zürich scheme) – describes the visible structure of the group.
These are published daily in the NOAA Solar Region Summary (SRS) and mirrored in SpectroSolHub.
The Mount Wilson scheme classifies a sunspot group by the topology of its magnetic field. It is the best predictor of flare activity.
- Alpha (α) – a single unipolar spot.
- Beta (β) – two dominant polarities, clearly separated.
- Gamma (γ) – mixed polarities without a clear east/west dipole.
- Delta (δ) – opposite polarities within the same penumbra, separated by less than 2°. Highest flare potential.
The classes combine: Beta-Gamma, Beta-Delta, Beta-Gamma-Delta groups carry progressively higher risk of M- and X-class flares.
The McIntosh classification uses three characters (e.g. Dkc) to describe the shape of a sunspot group.
- Character 1 – Z: modified Zürich class (A, B, C, D, E, F, H) – overall size / complexity.
- Character 2 – p: penumbra of the largest spot (x, r, s, a, h, k) – from none to large asymmetric.
- Character 3 – c: spot distribution in the group interior (x, o, i, c) – from open to compact.
Classes F and E with compact interiors (Fkc, Ekc) correspond to large, complex groups capable of major flares.
Area is reported in millionths of the visible solar hemisphere (µH). One millionth of the solar hemisphere is about 3 million km². A typical large sunspot group has an area of a few hundred µH. For scale, Earth projected onto the Sun covers about 170 µH.
NOAA numbers are assigned sequentially as new regions rotate into view or appear on the disk. They are never reused, so the number itself tells you roughly when the region first appeared (higher = more recent).
Live Sessions
Live sessions let observers share their solar imaging in real time. When a user activates Live mode in JSol'Ex 5.1+, processed images are pushed to SpectroSolHub as they are generated. Anyone with the link can watch the session unfold in their browser.
This is especially useful for public events, where an observer can share a URL or QR code so that attendees can follow the session on their phones or laptops.
When live sessions are active, a Live badge with a pulsing dot appears in the navigation bar.
This is especially useful for public events, where an observer can share a URL or QR code so that attendees can follow the session on their phones or laptops.
When live sessions are active, a Live badge with a pulsing dot appears in the navigation bar.
To start a live session, you need JSol'Ex version 5.1 or later and a SpectroSolHub account with an API token configured in JSol'Ex settings.
- Open the Share menu in JSol'Ex and click SpectroSolHub Live.
- Optionally enter a session name (e.g., "Live from backyards").
- Click Go Live.
- The live URL is displayed. Share it with your audience.
- Process SER files as usual. Images are pushed to SpectroSolHub automatically.
- Click Stop Live when done.
No account is needed to watch a live session. Simply open the shared URL or browse to the Live page from the navigation bar.
The viewer shows images organized by category (e.g., Processed, Colorized, Phenomena). Use the category tabs to switch between categories, and the dropdown menus to select specific image types. Images with the same title are grouped together, with previous/next navigation to browse through successive captures.
The viewer supports pan and zoom (mouse wheel, drag, pinch on touch devices), fullscreen mode, and keyboard navigation (arrow keys).
You can also download all images as a ZIP archive from the session page.
The viewer shows images organized by category (e.g., Processed, Colorized, Phenomena). Use the category tabs to switch between categories, and the dropdown menus to select specific image types. Images with the same title are grouped together, with previous/next navigation to browse through successive captures.
The viewer supports pan and zoom (mouse wheel, drag, pinch on touch devices), fullscreen mode, and keyboard navigation (arrow keys).
You can also download all images as a ZIP archive from the session page.