Solar Features And Events

Helioviewer.org’s solar features and events annotation layer is powered by the Heliophysics Events Knowledgebase (HEK) provided by the Lockheed Martin Solar & Astrophysics Laboratory (LMSAL).

Consult LMSAL’s HEK API Documentation for more information.

Events

GET /v2/events

Returns a list of HEK events in the Heliovewer Event Format.

Request Parameters

Parameter	Required	Type	Example	Description
startTime	Required	string	2023-01-01T00:00:00Z	Specific time to get predictions for.
sources	Optional	string	HEK,CCMC	Specify the external data sources to use for the request If not provided, all sources will be queried Allowed values: HEK, CCMC, RHESSI.
format	Optional	string	flat	Output shape. tree (default) returns the legacy nested category/group structure described in Heliovewer Event Format. flat returns the new v1 per-source response (one object per event with no category nesting). Allowed values: tree, flat.

See Heliovewer Event Format for the response format when format=tree (the default). When format=flat is requested, the response is the raw v1 events payload for each source, concatenated – no nesting, no group keys.

Event specific data conforms to the HEK Event Specification

Example: Get HEK Events for 2023-03-30 (tree, default)

Example Query (format=tree)

https://api.helioviewer.org/v2/events/?startTime=2023-03-30T00:00:00Z&sources=HEK

Example Response (format=tree)

[
    {
        "name": "Active Region",
        "pin": "AR",
        "groups": [
        {
            "name": "NOAA SWPC Observer",
            "contact": "http://www.swpc.noaa.gov/",
            "url": "N/A",
            "data": [
            {
                "absnetcurrenthelicity": null,
                "active": "true",
                "area_atdiskcenter": 213057280,
                "area_atdiskcenteruncert": null,
                "area_raw": null,
                "area_uncert": null,
                "area_unit": "km2",
                "ar_axislength": null,
                "ar_compactnesscls": "",
                "ar_lengthunit": "",
                "ar_mcintoshcls": "HAX",
                "ar_mtwilsoncls": "ALPHA",
                "ar_neutrallength": null,
                ...
            },
            ...
            ]
        },
        ...
        ]
    },
    ...
]

Example: Same request but with the new flat shape

Example Query (format=flat)

https://api.helioviewer.org/v2/events/?startTime=2023-03-30T00:00:00Z&sources=HEK&format=flat

Example Response (format=flat)

[
    {
        "absnetcurrenthelicity": null,
        "active": "true",
        "area_atdiskcenter": 213057280,
        "area_atdiskcenteruncert": null,
        "area_raw": null,
        "area_uncert": null,
        "area_unit": "km2",
        "ar_axislength": null,
        "ar_compactnesscls": "",
        "ar_lengthunit": "",
        "ar_mcintoshcls": "HAX",
        "ar_mtwilsoncls": "ALPHA",
        "ar_neutrallength": null,
        "concept": "Active Region",
        "frm_name": "NOAA SWPC Observer",
        "frm_institute": "NOAA-SWPC",
        "pin": "AR",
        ...
    },
    ...
]