Publications (27)
Visible Emission Line Coronagraph (VELC) onboard ADITYA-L1
Jagdev Singh, R. Ramesh, B. Raghavendra Prasad +21
Aditya-L1, India's first dedicated mission to study the Sun and its atmosphere from the Sun-Earth Lagrangian L1 location was successfully launched on 2023 September 2. It carries s…
Variation of Emission Line Width in Mid- and High-Latitude Corona
S. Krishna Prasad, Jagdev Singh, D. Banerjee
Spectroscopic studies of the solar corona, using the high spatial and spectral resolution 25-cm coronagraph at the Norikura observatory for equatorial off-limb observations, indica…
Equator to Pole Solar Chromospheric Differential Rotation using Ca-K Features Derived from Kodaikanal Data
Hema Kharayat, Jagdev Singh, Muthu Priyal +1
Differential rotation is one of the basic characteristics of the Sun, and it plays an important role in generating the magnetic fields and its activities. We investigated rotation…
Calibration of Spectropolarimetry channel of Visible Emission Line Coronagraph onboard Aditya-L1
Venkata Suresh Narra, K. Sasikumar Raja, Raghavendra Prasad B +11
The magnetic field strength and its topology play an important role in understanding the formation, evolution, and dynamics of the solar corona. Also, it plays a significant role i…
Variation of Chromospheric Features as a Function of Latitude and Time using Ca-K Spectroheliograms for Solar Cycles 15-23: Implications for Meridional Flow
Pooja Devi, Jagdev Singh, Ramesh Chandra +2
We have analysed the Ca-K images obtained at Kodaikanal Observatory as a function of latitude and time for the period of 1913 - 2004 covering the Solar Cycle 15 to 23. We have clas…
A consistency check for the calibration of 5303Ã solar coronal emission line observations with Aditya-L1/VELC
V. Muthu Priyal, R. Ramesh, Jagdev Singh +2
We carried out radiometric calibration of the Visible Emission Line Coronagraph (VELC) onboard Aditya-L1 at 5303Ã using observations of the Sun itself, a novel approach compared to…
A Statistical Analysis of Solar Surface Indices Through the Solar Activity Cycles 21-23
Umit Deniz Goker, Jagdev Singh, Ferhat Nutku +1
Variations of total solar irradiance (TSI), magnetic field, Ca II K-flux, faculae and plage areas due to the number and the type of sunspots/sunspot groups (SGs) are well establish…
Data Pipeline Architecture and Development for VELC onboard Space Solar Mission AdityaL1
Jagdev Singh, B. Raghavendra Prasad, Chavali Sumana +4
ADITYA L-1 is India's first dedicated mission to study Sun and its atmosphere with Visible Emission Line Coronagraph (VELC), a major payload on ADITYA-L1. VELC has provision to mak…
Oscillations in active region fan loops: Observations from EIS/{\it Hinode} and AIA/SDO
S. Krishna Prasad, D. Banerjee, Jagdev Singh
Active region fan loops in AR 11076 were studied, in search of oscillations, using high cadence spectroscopic observations from EIS on board Hinode combined with imaging sequences…
Relationship between Horizontal Flow Velocity and Cell Lifetime for Supergranulation
U. Paniveni, V. Krishan, Jagdev Singh +1
A study of 50 supergranular cells obtained from SOHO Dopplergrams was undertaken in order to investigate the relationship between the lifetime () and the horizontal flow velocit…
Variation of small scale magnetic fields over a century using Ca-K images as proxy
Jagdev Singh, Muthu Priyal, B. Ravindra +2
A combined uniform and long-time series of Ca-K images from the Kodaikanal Observatory (KO), Mount Wilson Observatory (MWO), and Mauna Loa Solar Observatory (MLSO) were used to ide…
Determining the Variations of Ca-K index and Features using a Century Long Equal Contrast Images from Kodaikanal Observatory
Jagdev Singh, Muthu Priyal, B. Ravindra
In the earlier analysis of Ca-K spectroheliograms obtained at Kodaikanal Observatory, the "Good" images were used to investigate variations in the chromosphere. Still, the contrast…
Aditya-L1/VELC observations of CME associated broadening of 5303Ã coronal emission line
K. Sasikumar Raja, V. Muthu Priyal, R. Ramesh +2
We present Aditya-L1/VELC spectroscopic observations of 5303Ã coronal emission line widths before and after coronal mass ejections (CMEs) which showed coronal dimming. The sit \& s…
Spectropolarimeter on-board the Aditya-L1: Polarization Modulation and Demodulation
K. Nagaraju, B. Raghavendra Prasad, Bhavana S. Hegde +5
One of the major science goals of the Visible Emission Line Coronagraph (VELC) payload aboard the Aditya-L1 mission is to map the coronal magnetic field topology and the quantitati…
Variations of the Ca II K Line Profile Parameters with Solar Latitude and Time Observed from Kodaikanal Solar Observatory
Apoorva Srinivasa, Anu Sreedevi, K P Raju +6
The Calcium-K line profiles as functions of solar latitude and time were obtained through our observations from the Kodaikanal Solar Observatory using the solar tunnel telescope an…
New Results on the Onset of a Coronal Mass Ejection from 5303 Ã Emission Line Observations with VELC/ADITYA-L1
R. Ramesh, V. Muthu Priyal, Jagdev Singh +3
We report on the onset of a coronal mass ejection (CME) using spectroscopic observations in 5303 Ã coronal emission line with the Visible Emission Line Coronagraph (VELC) onboard A…
Temporal and latitudinal variations of Ca-K plage and network area: An implication to meridional flows
Muthu Priyal, Jagdev Singh, Belur Ravindra +1
The Ca-K spectroheliograms obtained at the Kodaikanal observatory (KO) are used to generate a uniform time series using the equal contrast technique (ECT) to study the long and sho…
Thermal structure of coronal loops as seen with Norikura coronagraph
S. Krishna Prasad, Jagdev Singh, K. Ichimoto
The thermal structure of a coronal loop, both along and across the loop, is vital in determining the exact plasma heating mechanism. High resolution spectroscopic observations of t…
Correlation Between Sunspot Number and ca II K Emission Index
Luca Bertello, Alexei A. Pevtsov, Andrey Tlatov +1
Long-term synoptic observations in the resonance line of Ca II K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Syno…
Determination of the chromospheric quiet network element area index and its variation during 2008-2011
Jagdev Singh, B. Ravindra, R. Selvendran +4
Generally it has been considered that the plages and sunspots are the main contributors to the solar irradiance. There are small scale structures on the sun with intermediate magne…
Calibration of VELC detectors on-board Aditya-L1 mission
Shalabh Mishra, K. Sasikumar Raja, Sanal Krishnan V U +19
Aditya-L1 is the first Indian space mission to explore the Sun and solar atmosphere with seven multi-wavelength payloads, with Visible Emission Line Coronagraph (VELC) being the pr…
Long-term Variations in the Intensity of Plages and Networks as Observed in Kodaikanal Ca-K Digitized Data
Muthu Priyal, Jagdev Singh, Ravindra Belur +1
In our previous article (Priyal et al. in Solar Phys. 289, 127, 2014) we have discussed the details of observations and methodology adopted to analyze the Ca-K spectroheliograms ob…
Network and Plage Indices from Kodaikanal Ca-K Data
K. P. Raju, Jagdev Singh
The Ca II K filtergrams from Kodaikanal Solar Observatory have been used to study the solar activity. The images are dominated by the chromospheric network and plages. Programs hav…
Data processing of Visible Emission Line Coronagraph Onboard ADITYA L1
Muthu Priyal, Jagdev Singh, B. Raghavendra Prasad +28
ADITYA-L1 is India's first dedicated mission to observe the sun and its atmosphere from a halo orbit around L1 point. Visible emission line coronagraph (VELC) is the prime payload…
Polar Network Index as a magnetic proxy for the solar cycle studies
Muthu Priyal, Dipankar Banerjee, Bidya Binay Karak +4
The Sun has a polar magnetic field which oscillates with the 11 year sunspot cycle. This polar magnetic field is an important component of the dynamo process which is operating in…
Twin Telescope observations of the Sun at Kodaikanal Observatory
Jagdev Singh, B. Ravindra
We report the design, fabrication and installation of a 'Twin Telescope' at Kodaikanal Observatory intended to augment the ongoing synoptic observations of the Sun that has been ca…
Solar Coronal Magnetic Fields and Sensitivity Requirements for Spectropolarimetry Channel of VELC Onboard Aditya-L1
K. Sasikumar Raja, Suresh Venkata, Jagdev Singh +1
Understanding solar coronal magnetic fields is crucial to address the long-standing mysteries of the solar corona and solar wind. Although routine photospheric magnetic fields (MFs…