Calculation parameters for SLIPCAT
ParametersUnitsSTEREO-ASTEREO-BSTEREO-ASTEREO-BDescription (read Wang et al., ApJ, doi:10.1086/349572, 2010 for more details)
δ#5.05.0A small value used in creating rescaled images
thknl#2.03.2A threshold for kernel selection
thpro#1.72.2A threshold for region growing
rmax1Rs1.511.71.511.7An upper boundary above which there is no selected kernel
rmax2Rs1.541.731.541.73An upper boundary, The parameters of any prominences extending into the region above it is considered to be unreliable
snpixels55Size of a box used to remove noise-like kernels
smpixels55Size of a box used to merge regions which are very close to each other
ssppixels2020Size used to smooth the spine of a prominence
thareaMm^2500500A threshold to remove very small regions
thdishours22A threshold to judge if a prominence has disappeared
LDF 14.20, 4.70, 1.36 (Figure)1.20, 7.04, 0.30 (Figure)Linear discriminant function

Description of the parameter table of the SLIPCAT
Start The first time detected.
End The last time detected.
PA Position angle of the centroid at the first time, counterclockwise from north pole.
HGLon Longitude of the centroid at the first time in heliographic coordinate. Derived from the heliographic position of spacecraft and the position angle of the prominence.
HGLat Latitude of the centroid at the first time in heliographic coordinate.
P/M P: How many seperate parts in the prominence; M (Y or N): Is the part a major one compared to other parts.
Frames Number of frames in which the prominence is detected.
CL Confidence level. Number 1 has the highest liklihood to be a prominence.
r_cen Heliocentric distance of the brightness centroid of the prominence.
PA_cen Position angle of the brightness centroid of the prominence.
r_top Heliocentric distance of the top of the prominence.
Area Projected area of the prominence on the plane of the sky.
Length Characteristic length of the prominence (i.e., the length of the spine of the prominence).
Brightness Average brightness (i.e., digital number, DN) of the prominence.
Mean Mean value of the given parameter during the detection.
Min Minimum value of the given parameter during the detection.
Max Maximum value of the given parameter during the detection.
v Average first time derivative of the given parameter (i.e., the slope of the linear fitting line of the given parameter during the detection).
a Average second time derivative of the given parameter.
Clickable cell and highlight the multiple-part prominence.
Highlight the prominence with CL=2.
Highlight the prominence with CL=3.

SLIPCAT is an automated system developed by the STEP Team at USTC.
If you want to learn more about SLIPCAT and cite some papers in your researches related to SLIPCAT, refer to the following paper:
  • How does SLIPCAT work and the preliminary statisitical properties of prominences:
    Yuming Wang, Hao Cao, Junhong Chen, Tengfei Zhang, Sijie Yu, Huinan Zheng, Chenglong Shen, Jie Zhang, and S. Wang, Solar LImb Prominence CAtcher & Tracker (SLIPCAT): An Automated System and Its Preliminary Statistical Results, ApJ, 717(2), 973-986, 2010 (download at arXiv or local).
  • About Eruptive Prominences:
    Kai Liu, Yuming Wang*, Chenglong Shen, and S. Wang, Critical Height for the Destabilization of Solar Prominences: Statistical Results from STEREO Observations, ApJ, 744, 168(10pp), 2012 (download at arXiv).
We acknowledge the use of the data from STEREO/SECCHI (
This project is supported by the grants from NFSC (40525014), the 973 program (2006CB806304), etc.
Comments or questions should be addressed to Yuming Wang. Also, you may leave your thoughts here.