Leto et al. – 2nd AtmoHEAD, Padua – 19-21 May 2014 1

All sky camera, Lidar, and Electric Field Meter for the ASTRI SST-2M prototype for CTA

G. Leto, R. Zanmar Sanchez, G. Bellassai, P. Bruno, M.C. Maccarone, E. Martinetti

(for the ASTRI Collaboration and the CTA Consortium)

Leto et al. – 2nd AtmoHEAD, Padua – 19-21 May 2014 2

The ASTRI Program… in brief

The ASTRI Program is an Italian “Progetto Bandiera” funded by the Ministry of Education, University and Research and led by INAF, the Italian National Institute of Astrophysics.

Main goals: design, development and production, within the Cherenkov Telescope Array, CTA, framework and following its requirements, of

an end-to-end prototype of a Dual-Mirror Small Size Telescope, SST-2M, devoted to the highest gamma-ray energy region (1-100 TeV) investigated by CTA, to be tested under field conditions in 2014, a SST-2M mini-array to be placed at the final CTA Southern Site during 2016, which would constitute the first seed of the CTA Observatory,the mirrors for the prototype of the CTA Medium Size Telescopes, MST.

ASTRI, ‘’Astrofisica con Specchi a Tecnologia Replicante Italiana’’

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The ASTRI SST-2M telescope

… devoted to investigate the VHE region, 1-100 TeV, in a wide field of view, 9.6° full FoV, making use of innovative technological solutions:

a dual-mirror optics Schwarschild-Couder configuration,

The prototype

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The ASTRI SST-2M telescopeThe prototype

… and:

a compact focal plane camera (50x50x50 cm3) based on Si-PMs sensorsmanaged by a specifically designed front-end electronics.

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The site for the ASTRI prototypeSerra La Nave (SLN)

The ASTRI SST-2M prototype will be placed, at the INAF ”M.G. Fracastoro” observing station located in Serra La Nave on the Etna Mountain near Catania.

Latitude: 37° 41’ 05” N Longitude: 14° 58’ 04” EAltitude: 1735 m a.s.l

After the verification tests, devoted to probe the technological solutions adopted, the ASTRI SST-2M prototype will perform scientific observations on the Crab Nebula and on some of the brightest TeV sources … Serra La Nave

The ASTRI SST-2M telescope is an end-to-end prototype that will be tested on field.

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The site for the ASTRI prototypeMonitoring the atmosphere at SLN – Auxiliary Instrumentation

Qui aggiungerei la lista della strumentazione ausiliaria a SLN, in senso lato, (Weather Station, EFM, Lidar, All-sky camera, Pludix, UVscope, …) ponendo in evidenza quella di cui tratterà la presentazione stessa.Da qualche parte c’era una slide di questo tipo … mò la cerco!

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Auxiliary Instrumentation at SLNThe Electric Field Meter, EFM

•Developed by the INAF Radio Astronomy Institute (IRA), contact Federico Perini•Field-Mill sensor

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Auxiliary Instrumentation at SLNEFM at work

Etna Eruption 23 November, 2013

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Auxiliary Instrumentation at SLNEFM – SLN output alarms

Jan 5 2014 storm

First derivative

Signal +Alarm bits

Alarm bits issued from software are weighted to create an alert to ASTRI SST-2M

• Can issue alarms• NO distance/direction (3 EFM needed!) • Can detect lightening distance > 7 km!!

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Auxiliary Instrumentation at SLNRaman Lidar - AMPLE

•Build for the VAMOS SEGURO project byCNISM, Napoli (contact Nicola Spinelli)

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•AMPLE characteristicsElastic channel at 355nm.Polarization measurements available.Raman channel at 386nm.Raw spatial resolution from 30cm to 30mCan be pointed from software

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Auxiliary Instrumentation at SLNRaman Lidar - EARLINET

•Part of EARLINET since 2013: atmosphere monitoring routinely carried out.

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Auxiliary Instrumentation at SLNAll-Sky Camera, ASC

•SBIG All-Sky Camera 340C•Kodak KAI-340 CCD 640x480•Exposure time 50 microseconds to 180 sec•One image every five minutes

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Auxiliary Instrumentation at SLNASC: Color = Bayer Filter

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Auxiliary Instrumentation at SLNASC: Cloud Detection

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•Statistics of cloud cover for the SST-2M site day and night.•Support SST-2M observations.

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Auxiliary Instrumentation at SLNASC- Thresholding

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•Usually the 3 RGB channels are turned into one: R-B or R/B(Long et al. 2006)RGB turned into HSL and L is used (Souza-Echer et al 2006)Euclidean Geometric Distance (Sylvio et al 2010)

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Auxiliary Instrumentation at SLNASC - Thresholding

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•Classified by eye 25,000 images intoclear sky, overcast, lunar phase, sun altitude.

Principal Component Analysis

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Auxiliary Instrumentation at SLNASC - Thresholding

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Principal Component Analysis

Eigenvector

Eigenvalue R G B

9.2e7 0.5 0.6 0.6

1.6e6 0.7 0.1 -0.7

2.9e4 -0.5 0.8 -0.4

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Auxiliary Instrumentation at SLNASC - Thresholding

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Principal Component Analysis

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Auxiliary Instrumentation at SLNASC - Thresholding

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Auxiliary Instrumentation at SLNASC - Thresholding

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Auxiliary Instrumentation at SLNASC - Star Counting

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Find stars

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Auxiliary Instrumentation at SLNASC - Star Counting

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Confront with a catalog

We need an accurate transformation between pixel and celestial coordinates

ZEA projectionDistortions modeled with 6 order polynomial series

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Auxiliary Instrumentation at SLNASC - Star Counting

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Discard Outliers

Fit for the magnitude transformation

zeropoint 12.7+-0.2

slope 1.04+-0.02

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Auxiliary Instrumentation at SLNASC - Star Counting

Tiling

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Auxiliary Instrumentation at SLNASC - Star Counting

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Auxiliary Instrumentation at SLNASC - Star Counting

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Auxiliary Instrumentation at SLNASC - Star Counting

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Auxiliary Instrumentation at SLNConclusions and Future Work

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All Sky Camera: ThresholdingTry extra rotation to turn problem one-dimensionalWork cases with the moon in the skySunset and sunrise

All Sky Camera: Star countingBuild our own catalog

EFM:Deliver real alerts to ASTRI SST-2M software (dummy software already implemented)

Lidar:Data taken during ASTRI SST-2M observation will be available to define the real sky condition

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The ASTRI Program

http://www.brera.inaf.it/astri/