1. Questionnaire survey on standard stars
Topics of the survey:
Basic info about polarimetric project
Used instrument
Requirements for science targets
Information about used standard stars
Interesting feedback: Thank you!
9 forms received (10 projects)

2. Science topics: Solar system objects
Kiselev Nikolay
Comets, scattering and molecular emission
Vis. Polarimetry
Linear (+circ )
Hadamcik (Levasseur-Regourd)
Comets, Asteroids scattering
Vis. Polarimetry and imaging pol. linear
Rosenbush Vera
Asteroids, Moons, minor bodies
Vis. Polarimetry, imaging pol., spec.pol, linear
Comets, circular polarization (multiple scattering, chirality)
Vis. Polarimetry, circular (+lin.)
Schmid, Hans Martin
Giant planets, limb polarization
Vis. imaging pol. spec. pol linear

3. Science topics: stellar physics
David Buckley
Magnetic CVs (polars)
Vis. pol. spec.pol,
circular+linear
Kochukhov O.
Zeeman spectropol. of magnetic stars
Vis. Spec.pol (HR) circular+linear
Harrington David
Herbig and Be stars, scattering, pumping
Vis. Spec.pol (HR)
linear
Hashimoto Jun
Circumstellar disks, scattering
IR, AO, imaging pol. linear
Science topics: extra-galactic
Heidt Jochen
Radio-loud AGNs polarization var.
Vis. Imaging. pol, linear

4. Requirements and limitations
Targets Autor Sensitivity Limitations
n ins. cal, var. bckg.
Comets, asteroids, Hadamcik, % x x
Planets, limb Schmid % x x
Comets Kiselev % x x
Minor bodies, comets Rosenbush % x x x
protopl.. Disks Hashimoto % x x
Magnetic CVs Buckley % x x
Herbig, Be stars Harrington % x x
Ap-stars Zeeman Kochukov % x x x
RL-AGN variab. Heidt % x

5. Use of standard stars
All programs (except 1) use 0-pol. and high-pol. standards
All programs on circ. Polarization use circ-pol standards
Use of 0-pol. standards
6 calibration of instrument polarization
3 check (circumstellar disks, planet limbs, AGN)
1 not used (Zeeman pol.)
Use of high pol. standards
9: check (cal) 0 degr. polarization angle , efficiency-check
3: cross talk check
0: not used
Use of circ. Pol standards
5: Check-V
3: Check-cross talk
5: Not used (linear polarization)

6. Properties of 0-pol standard stars
Brightness of 0-pol. standards
0: too faint
8: O.K 
3: too bright
Distribution of 0-pol. standards
2: good
2: O.K.
6: poor 
Quality of 0-pol. standards
1: high
8: O.K 
0: poor

7. Properties of high-pol standards
Brightness of high-pol. standards
1: too faint
7: O.K 
1: too bright
Distribution of high-pol. standards
1: good
2: O.K 
8: poor
Quality of high-pol. standards
1: high
8: O.K 
0: poor

8. Properties of circ-pol standards
Brightness of circ-pol. standards
3: too faint
0: O.K 
1: too bright
Distribution of circ-pol. standards
0: good
1: O.K 
3: poor
Quality of circ-pol. standards
0: high
2: poor

9. References for standard stars
3: Whittet et al.(1992)
3: Tunschek et al. (1992)
2: Schmidt et al. (1992)
2: Heiles (2000)
2: Angel and Landstreet (1970) circ.
2: Hsu + Breger (1982)
2: Serkowski – UKIRT-List
2: FORS-list
1: Michalsky 1976
1: slowly rot. AP stars (Zeeman-spect.)

10. What should be improved with standard stars
All types of standards
3: higher accuracy
4: less variable
8: more standard objects
2: fainter standards
3: brighter (circ). standards
1: R-band data missing

11. Summary Survey gives some clear hints Main use of calibration targets
calibration of instrument polarization
check/cal. 0-degr angle, check efficiency
check V signal
Main problems of standard stars
Distribution of 0-pol. and high-pol. is poor
Circular polarization standards are bad (all prop)
Requirements
More standard stars
Higher accuracy, less variable

12. What could be done? 1) Are there unpublished data on standard stars?
 survey the archives
 coordinate expertise within COST
can the distribution of standards be improved?
2) elaborate the exact requirements for better instrument calibration with standard stars
3) Try to get new data if required