irsol observing programs and interactions with data ... · irsol observing programs and...
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IRSOL observing programs and interactions with data collected by space missions
Renzo Ramelli and IRSOL collaborators
IRSOL Locarno, Switzerland
Oslo, Norway
8th August 2013
Outline
• IRSOL observatory and telescope• ZIMPOL polarimeter
• Examples of selected recent observing programs• Examples of Interaction with space observations• Perspectives of IRSOL
IRSOL (Istituto Ricerche Solari Locarno)
Switzerland
Zurich
Is a medium sized telescope (45 cm) still interesting for science?
• To test and develop instrumentation and observing methods that can be transferred to other larger facilities (e.g. ZIMPOL@Gregor)
• More flexibility in the observing time schedule (synoptic programs, reaction to particular solar events)
• Exploit particular telescope characteristics, e.g. for IRSOL:– Instrumental polarization easy to handle
– Low amount of stray light
Telescopelayout
The IRSOL instrumentation
Telescope • Telescope: Gregory - Coudé, evacuated – Diameter of primary mirror: 45 cm– Total focal length: 25 m
• Spectrograph:focal length: 10 mgrating 18 cm × 36 cm 316 lines / mmblaze 63°
• Fabry Perot:Bandwidth ~ 30 mANovel configuration with FP+spectrograph
• ZIMPOL polarimeter (see next slides)
• Adaptive optics:Tip-tiltDM with 37 actuators
ZIMPOL polarimeter
• ZIMPOL-polarimeter (Zurich Imaging Polarimeter) allows precise full Stokes measurements free form seeing induced spurious effects (modulation 42 kHz / 1kHz).
• Basic principle: high frequency modulation, demodulation with dedicated special CCD
• Polarimetric accuracy depends primarily on photon statistics. 10-5 level can be reached with long enough exposure time.
ZIMPOL - setup
ZIMPOL3 microlenses
ZIMPOL3New generation camera system which is now used for observations at IRSOL (Ramelli et al. 2010, SPIE proc.)
ZIMPOL3
• more flexible and compact system• adaptable to different CCD-chips
– new larger CCD for UV with microlenses
• more efficient and faster• based on newer technology
(replace components available on the market)
• more functions (different demodulation schemes, electronic compensation of telescope polarisation offset, ...)
Major improvements:
Other recent improvements in the instrumentation
• Prisma pre-disperser substituted by filter-wheel with high transmission filters
• New electronics for control of spectrograph
• Limb tracker based on slit jaw image (circle fit of the limb)
• Automatic scripts for routine observations
• Soon → new Ag coating
Second solar spectrum observationsSynoptic program(see Kleint et al. 2010, A&A)
Monthly observations at different
- Position angles (N, NW, W, SW, S)- C2
lines at 5140 A
Slit parallel to the limb, at µ=0.15 (10“ from limb)
Are there variations with the solar cycle?
N
S
Examples of on-going projects:
Example of scattering polarization observation of C2 lines
R R R
P
1 2 3
Observation of faint emission lines in prominences (Ramelli, Stellmacher, Wiehr, Bianda et al. 2012, Solar Phys.)
HeII
Inversion of prominence profiles with HaZel code
(HaZel code: Asensio Ramos, Trujllo Bueno and Landi degl’Innocenti, ApJ, 2008)
(Ramelli et al.)
Examples of on-going projects:
Example of interaction with space observations
• (Non)-observation of the impact polarization in solar flares in the Hα line.
(Bianda et al. 2005, A&A).
• Any clear signal detected above sensitivity of 10-3
Simultaneous observation of 5247/5250 Fe and 6301/6302 Fe line pairs
(Stenflo, Demidov, Bianda, Ramelli, 2013, A&A)
Perspectives at IRSOL
• Financing: now ok
• Soon new manpower (1-2 staff + 1 postdoc)
• Give contributions for polarimetry at large telescopes (e.g. ZIMPOL@Gregor → first test campaign foreseen in October 2013)
• Continue high precision spectropolarimetry at IRSOL with improved instrumentation
Thanks for your attention!