The Inner Coronagraph on Board ADITYA-L1 and Automatic Detection of CMEs

2017 ◽  
Vol 13 (S335) ◽  
pp. 340-343 ◽  
Author(s):  
D. Banerjee ◽  
R. Patel ◽  
V. Pant ◽  
Keyword(s):  
Emission Line ◽  
Coronal Mass Ejections ◽  
Automatic Detection ◽  
Primary Objective ◽  
Field Of View ◽  
Visible Emission ◽  
Spectroscopic Observations

AbstractVisible Emission Line Coronagraph (VELC) on board ADITYA-L1 is an internally occulted coronagraph with mirror as its primary objective element. It has a field of view (FOV) starting from 1.05 R⊙– 3 R⊙. It will observe the corona in continuum centered at 5000 Å and will perform spectroscopic observations of inner corona in two visible (5303 Å and 7892 Å) and one infrared (10747 Å) wavelengths. VELC will be capable of observingthecorona with high spatial and temporal resolutions. We present an overview of the inner coronagraph (VELC) design and introduce the concept of an on-board automated coronal mass ejections (CMEs) detection logic proposed for this payload.

scholarly journals Automated detection of Coronal Mass Ejections in Visible Emission Line Coronagraph (VELC) on-board ADITYA-L1

2018 ◽  
Vol 13 (S340) ◽  
pp. 171-172
Author(s):  
Ritesh Patel ◽  
K. Amareswari ◽  
Vaibhav Pant ◽  
Dipankar Banerjee ◽  
K. Sankarasubramanian
Keyword(s):  
Emission Line ◽  
Coronal Mass Ejections ◽  
Detection Algorithm ◽  
Automated Detection ◽  
Field Of View ◽  
Visible Emission ◽  
Signal To Noise ◽  
Difference Images

AbstractAn onboard automated coronal mass ejections (CMEs) detection algorithm has been developed for Visible Emission Line Coronagraph (VELC) onboard ADITYA-L1. The aim of this algorithm is to reduce the load on telemetry by sending the high spatial (~ 2.51 arcsec pixel−1) and temporal (1 s) resolution images of corona from 1.05 R⊙ to 3 R⊙, containing CMEs and rejecting others. It is based on intensity thresholding followed by an area thresholding in successive running difference images which are re-binned to lower resolution to improve signal to noise. Here we present the results of application of the algorithm on synthetic corona images generated for the VELC field of view (FOV).

scholarly journals The Kepler field of view covered with the LAMOST spectroscopic observations

2015 ◽  
Vol 11 (A29B) ◽  
pp. 514-516
Author(s):  
Joanna Molenda-Żakowicz ◽  
Peter De Cat ◽  
Jian-Ning Fu ◽  
An-Bing Ren ◽  
Antonio Frasca ◽  
...  
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
Effective Temperature ◽  
Field Of View ◽  
Surface Gravity ◽  
High Resolution Spectroscopy ◽  
Optical Fibres ◽  
Low Resolution ◽  
Spectroscopic Observations ◽  
The Mean

AbstractThe Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) at the Xinglong observatory in China is a 4-m telescope equipped with 4,000 optical fibres. In 2010, we initiated the LAMOST-Kepler project which aimed at collecting low-resolution spectra of stars from the Kepler Input Catalog covering uniformly the Kepler field of view. The first round of the LAMOST-Kepler project has been completed in September 2014 resulting in more than 100,000 low-resolution spectra. We used those data to derive the effective temperature, the surface gravity, and the mean metallicity of our targets, as well as to detect fast rotators, and to identify emission-line stars. Our results are consistent with those reported in the literature and derived from high-resolution spectroscopy. The second round of the LAMOST-Kepler project will allow to improve the coverage of the Kepler field and to repeat observations of selected targets.

scholarly journals Characterizing Spectral Channels of Visible Emission Line Coronagraph of Aditya-L1

2021 ◽  
Vol 8 ◽  
Author(s):  
Ritesh Patel ◽  
A. Megha ◽  
Arpit Kumar Shrivastav ◽  
Vaibhav Pant ◽  
M. Vishnu ◽  
...  
Keyword(s):  
Emission Line ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Plasma Temperature ◽  
Slit Width ◽  
Field Of View ◽  
Visible Emission ◽  
Line Profiles ◽  
Signal To Noise ◽  
Spectral Channels

Aditya-L1 is India’s first solar mission with the Visible Emission Line Coronagraph (VELC), which consists of three spectral channels taking high-resolution spectroscopic observations of the inner corona up to 1.5 Rʘ at 5,303, 7,892, and 10,747 Å. In this work, we present a strategy for the slit width optimization of the VELC using synthetic line profiles by taking into account the instrument characteristics and coronal conditions for log(T) varying from 6 to 6.5. The synthetic profiles are convolved with simulated instrumental scattered light and noise to estimate the signal-to-noise ratio (SNR), which will be crucial to designing the future observation plans. We find that the optimum slit width for VELC turns out to be 50 μm, providing sufficient SNR for observations in different solar conditions. We also analyzed the effect of plasma temperature on the SNR at different heights in the VELC field of view for the optimized slit width. We also studied the expected effect of the presence of a CME on the spectral channel observations. This analysis will help to plan the scientific observations of VELC in different solar conditions.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Imaging and Spectroscopic Observations of the Case Survey Blue/Emission- Line Galaxies

1995 ◽  
Vol 109 ◽  
pp. 2376 ◽  
Author(s):  
John J. Salzer ◽  
J. Ward Moody ◽  
Jessica L. Rosenberg ◽  
Stephen A. Gregory ◽  
Michael V. Newberry
Keyword(s):  
Emission Line ◽  
Blue Emission ◽  
Spectroscopic Observations ◽  
Emission Line Galaxies

Visible emission line space solar coronagraph: science and optical design

2013 ◽  
Vol 42 (2) ◽  
pp. 96-100 ◽  
Author(s):  
Jagdev Singh ◽  
Raja Bayanna ◽  
K. Sankarasubramanian
Keyword(s):  
Emission Line ◽  
Optical Design ◽  
Visible Emission ◽  
Line Space

scholarly journals Magnetic activity and solar-like pulsations of X-ray sources in the Kepler field of view

2012 ◽  
Vol 8 (S294) ◽  
pp. 205-206
Author(s):  
Joanna Molenda-Żakowicz ◽  
Antonio Frasca ◽  
Hans-Erich Fröhlich
Keyword(s):  
High Resolution ◽  
Magnetic Activity ◽  
Field Of View ◽  
X Ray ◽  
Spectroscopic Observations ◽  
Sky Survey ◽  
Cross Matching

AbstractWe report on cross-matching the ROSAT All-Sky Survey and the XMM-Newton catalogs with the Kepler Input Catalog (KIC). For several stars associated with X-ray sources, we provide also an access to our high-resolution spectroscopic observations.

scholarly journals Analysis of Signal to Noise Ratio in Coronagraph Observations of Coronal Mass Ejections

2020 ◽  
Author(s):  
Johannes Hinrichs ◽  
Jackie A. Davies ◽  
Matthew J. West ◽  
Volker Bothmer ◽  
Bram Bourgoignie ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Signal To Noise Ratio ◽  
European Space Agency ◽  
Leading Edge ◽  
Outer Edge ◽  
Field Of View ◽  
Signal To Noise ◽  
Space Agency ◽  
Noise Ratio ◽  
Improved Performance

<p>Aims. We analyse the Signal-to-Noise Ratio (SNR) requirements of the European Space Agency (ESA)-funded Solar Coronagraph for OPErations (SCOPE) instrument with respect to the manual and automatic detection of Coronal Mass Ejections (CMEs) in its field of view of 2.5 to 30 solar radii.<br />Methods. For our analysis, SNR values are estimated from observations made by the C3 coronagraph on the Solar and Heliospheric Observatory (SOHO) spacecraft for a number of di erent CMEs. Additionally, we generate a series of artificial coronagraph images, each consisting of a modelled coronal background and a CME, the latter simulated using the Graduated Cylindrical Shell (GCS) model together with the SCRaytrace code available in the Interactive Data Language (IDL) SolarSoft library. Images are created with CME SNR levels between 0.5 and 10 at the outer<br />field of view (FOV) edge, generated by adding Poisson noise, and velocities between 700 km s-1 and 2800 kms-1. The images are analysed for the detectability of the CME above the noise with the automatic CME detection tool CACTus.<br />Results. We find in the analysed C3 images that CMEs near the outer edge of the field of view are typically 2%of the total brightness and have an SNR between 1 and 4 at their leading edge. The automated detection of CMEs in our simulated images by CACTus succeeded well down to SNR = 1 and for CME velocities up to 1400 kms-1. At lower SNR and higher velocity of 2100 kms-1 the detection started to break down. For SCOPE, the results from the two approaches confirm that the initial design goal of SNR = 4 would, if achieved, deliver improved performance over established data used in operations today.</p>

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