INAF/OACT Latest USSPS

Introduction

All daily drawings of the sunspot groups and USSPS produced by INAF-Catania Astrophysical Observatory are available in the archive. Daily drawings of sunspot groups and pores are made by a Cooke refractor on a 24.5 cm diameter projected image of the Sun. These drawings are used to determine some characteristics of the SunSPotS group visible on the photosphere and to report them in form of a numerical code (ursigram), named USSPS. The USSPS describe the main characteristics of the SunSPotS groups observed in the photosphere.

Using the daily observation of the photosphere performed by the Equatorial Spar of INAF - Catania Astrophysical Observatory, we provide an indication of the probabilities that each sunspot group visible on the solar disc may host solar flares of C-, M- and X- class.

The sunspot groups capability of hosting flares is based on the Poisson statistics of five parameters: number of sunspots and pores, projected area of sunspot group in tens of millionths of the solar hemisphere, group type according to Zurich classification, type of penumbra of the main sunspot, and relative importance between leading sunspot and density of the sunspot population (Falco, M., Costa, P., Romano, P., "Solar flare forecasting using morphological properties of sunspot groups", 2019, Journal of Space Weather and Space Climate, Volume 9, id.A22, 9pp. DOI:10.1051/swsc/2019019).

Technical information

All the information about the sunspot groups are reported in the ursigram with the following format:

USSPS 31405 JJHHH aaabc ddeee QXXYY fghii,

where:
JJ = Catania date of observation
HHH = hours and tenths of hours (UT)
aaa = Wolf number
b = seeing quality (1=very poor, 5=exceptional)
c = solar disk dimension (2 for Catania drawing)
dd = Catania serial number of sunspot group
eee = area of sunspot group in tens of millionths of the solar hemisphere
Q = quadrant (heliographic coordinate) in which geometric center of sunspot group is located:

• 1 = NE
• 2 = SE
• 3 = SW
• 4 = NW

XX = distance to central meridian in degrees
YY = heliographic latitude in degrees
f = type of penumbra
g = relative importance of leading spot and density of the sunspot population
h = Zurich sunspot class
ii = number of spots in the group

Limitations and caveats of the data

Daily drawings of sunspots groups and pores are maken between 8:00 and 14:00 local time (CET/CEST). When the weather is cloudy or ash falls due to the Etna eruptions the drawings are not provided.

The accuracy of the drawings depends on the experience of the operator and on their ability to distinguish the structures of the photosphere that are projected on the sheet.

Use and functionality of the product

In the USSPS archive webpage, clicking on the "Search" button provides the number of found records. Each record is identified by the date of observation. For each record three links appear:

• a link to view the USSPS ("View USSPS file")
• a link to download the USSPS in .txt format ("Download USSPS file")
• a link to display the JPEG 2000 version of the corresponding drawing("View Sunspot drawing").

A grey bar reporting different week of the year will help to distinguish different time intervals.

On the left side of the Latest USSPS webpage it is shown the ursigram and on the right side it is shown the corresponding drawing in JPEG 2000 format. Click on the image for a larger display.

The latest USSPS from Catania in a .txt format can be also downloaded clicking on "download".

API access to INAF/OACT Sunspot group characteristics

Introduction

This product can also be used via a Web API (application programming interface) for programmatically accessing the files by requesting specific URL-encoded parameters. The list of mandatory and optional variables for this specific product are included in tables 1 and 2 below:

Table 1: Mandatory parameters for API access to INAF/OACT Sunspot group characteristics.

Variable	Values required for this product
pc	S123a | 123ad
component	latest | archive

Table 2: Optional parameters that can be set to refine the query.

Variable	Values
query_date	yyyy-MM-ddT
img_ext	txt | jpeg

Access to the latest data

To access the latest data, the "component" parameter in the address bar needs to be set to "latest": component=latest.

The latest USSPS file is available at:

https://ssa.oact.inaf.it/prod/API/index.php?component=latest&pc=S123a

The webpage link returns the URL to the latest INAF/OACT Sunspot group characteristics file (USSPS.txt).

Example:

https://ssa.oact.inaf.it/prod/API/index.php?component=latest&pc=S123a

returns

https://ssa.oact.inaf.it/prod/data/latest_data/Latest_USSPS.txt

The latest draw file is available at:

https://ssa.oact.inaf.it/prod/API/index.php?component=latest&pc=S123ad

The webpage link returns the URL to the latest INAF/OACT Sunspot drawing file.

Example:

https://ssa.oact.inaf.it/prod/API/index.php?component=latest&pc=S123ad

returns

https://ssa.oact.inaf.it/prod/data/latest_data/Latest_Draw.jpg

Access to archive data

To access archive data, the "component" parameter in the address bar needs to be set "archive": component=archive.

In order to select a specific day, the following parameter needs to be setted: "query_date" using the format yyyy-MM-ddT.

For example: https://ssa.oact.inaf.it/prod/API/index.php?component=archive&pc=S123a&query_date=2020-06-15&img_ext=txt

This returns a JSON containing a list of all archived INAF/OACT Sunspot group characteristics file (USSPS.txt) during the selected date (here the 2020-06-15).

In order to select from different image products, the data type parameter can be added:

"img_ext = txt" returns the USSPS.txt file;

"img_ext = jpeg" returns the Sunspot drawing file.

This returns a JSON containing the archived INAF/OACT Sunspot group characteristics file or Sunspot drawing file during the selected day.

The data structure of the returned JSON is as follows:

JSON format for img_ext=txt and img_ext=jpeg

For example, the link above returns:

{"./data/ussps/2020/06/200615.txt": {"size":"---","modify":"---"}}