1. Preparation for observations (II) Prof. Qian Shengbang, Drs. He Jiajia, Zhao Ergang, Zhang Jia Yunnan Astronomical observatory April 4, 2011 The 33th International School for Young Astronomers ISYA-2011, Lijiang, China

2. GaoMeiGu Location: 560km northwest to Kunming 40km southwest to Lijiang city Observational Station

3. Preparation for observations Scientific and observational purposes; Information of the observational site, telescope, and terminal (e.g., CCD); Information of the objects (when the objects rise and set; how far the objects from the Moon, and how long can we observe them in one night); Star charts of the selected objects, etc.

4. Photometric Objects No.ObjectRA (2000)Dec (2000)MagnitudePurpose * 1DP Leo11:17:16.0+17:57:4217.5-19.0 EP & MT 2IR Com12:39:32.1+21:08:0613.4-18.5 EP & MT 3QS Vir13:49:52.0-13:13:3714.3-17.8 MT & LC 4NN Ser15:52:56.2+12:54:4716.6-17.2 MT & LC 5V2051 Oph 17:08:19.1-25:48:3013.0-17.5 EP & MT 6NSVS1425682520:20:00+04:37:56.513.2-14.0 MT & LC 7V50 in M416:20:27.2-26:24:51.817.2-18.0 MT & LC 8V53 in M416:20:34.4-26:25:14.615.8-16.4 MT & LC 9SDSSJ082053.508:20:53.53+00:08:43.414.7-15.6 EP & LC 10SDSSJ162256.616:22:56.66+47:30:51.115.5-16.2 EP & LC * EP: Eclipsing Profile MT: Mid-eclipsing Time LC: Light Curve RA=right ascension Dec=declination

5. The name of object(I) 1. Leo= Leo Com= ComaBerenices Vir=Virgo Ser= Serpens Oph= Ophiuchus There are 88 constellations.

6. How to name a variable star in a constellation: The name of the first variable in a constellation is “R”, e.g., R Vir. 1. R 、 S 、 T 、 U 、 V 、 W 、 X 、 Y 、 Z 。 [9] 2. RR 、 RS……RZ ， SS 、 ST……SZ ， ……ZZ ， [54] 3.From the 55 th, AA 、 AB……AZ ， BB 、 BC……BZ ， ……QZ ， we never use the letter J. [334] 4.From V355, we use : V355 、 V356…… Add the constellation name after the letter or number

7. The name of object(II) NSVS14256825 NSVS=Northern Sky Variability Survey The Northern Sky Variability Survey (NSVS) is a temporal record of the sky over the optical magnitude range from 8 to 15.5. It was conducted in the course of the first-generation Robotic Optical Transient Search Experiment (ROTSE-I) using a robotic system of four comounted unfiltered telephoto lenses equipped with CCD cameras. All NSVS photometric measurements are available for on- line public access from the Sky Database for Objects in Time- Domain ((SkyDOT)) at Los Alamos National Laboratory. Copies of the full survey photometry may also be requested on tape. http://skydot.lanl.gov/nsvs/nsvs.php

8. The name of object(III) V50 in M4 、 V53 in M4 V50=the fiftieth variable star V53=the fifty-third variable star M4=the fourth Messier Catalog 1774: M1~M45 1780: M46~M70 1781: M71~M 103 Now: M110

9. The name of object(IV) SDSSJ082053.5 and SDSSJ162256.6 SDSSJ= Sloan Digital Sky Survey Sloan Digital Sky Survey http://www.sdss.org/ The Sloan Digital Sky Survey (SDSS) is one of the most ambitious and influential surveys in the history of astronomy. Over eight years of operations (SDSS-I, 2000- 2005; SDSS-II, 2005-2008), it obtained deep, multi-color images covering more than a quarter of the sky and created 3-dimensional maps containing more than 930,000 galaxies and more than 120,000 quasars 082053.5 and 162256.6 are the right ascensions of the variable stars.

10. The types of Objects No.Object type 1DP Leo Eclipsing Polar 2IR Com Eclipsing dwarf novae 3QS Vir Hibernating cataclysmic variable 4NN Ser Eclipsing white-dwarf binary 5V2051 Oph Eclipsing dwarf novae 6NSVS14256825 Sub-dwarf B-type eclipsing binary 7V50 in M4 EB-type binary in Globular Cluster 8V53 in M4 W UMa-type binary in Globular Cluster 9SDSSJ082053.5 Sub-dwarf B-type eclipsing binary 10SDSSJ162256.6 Sub-dwarf B-type eclipsing binary

11. DP Leo ---- AM Her type cataclysmic binaries RA: 11:17:16.0 Dec: +17:57:42 (J2000) Magnitude : V = 17.5 P orb =0.06236285648 d = 89.9 m i=79.5° the first eclipsing polar --a synchronously rotating magnetic white dwarf accretes matter from its Roche-lobe filling companion (1985ApJ_293__303) It was found to be a two-pole accretor based on the detection of cyclotron emission lines in field strengths of 30.5MG and 59MG (1993MNRAS_260__696) 1985ApJ_293__303

12. WD : T eff =13500K (due to accretional heating) Min I =2448773.214896 +0.06236284126 × E Qian et al. (2010) found that a reversal of the long-term trend had taken place and suggested that the data support a sinusoidal variation instead. They attributed this modulation to a giant planet, which moves around the close binary in a wide circular orbit with a period of 23.8 yrs. Schwope et al. (2002) and Pandel et al. (2002) noted a decrease of the binary period that could be described by a quadratic term in the ephemeris back→

13. QS Vir (EC 13471 -1258) ---Eclipsing binary of Algol type RA: 13 49 51.95 Dec: -13 13 37.5 WD + red dwarf Magnitude: B = 16.17 Discovered in the Edinburghcape faint blue object survey of high galactic latitudes (Kilkenny et al.1997) O’Donoghue et al. (2003) suggested that QS Vir is a hibernating cataclysmic variable. q = 0.66 T WD =14000 K P = 0.150757525 d = 3.618 h

14. QS Vir MJD(BTDB) = 48689.140 62(1) + 0.150 757 525(1)E.Epoch:

15. The LC of QS Vir

16. The planet in QS Vir

17. NN Ser ( PG 1550 + 131) --- nova-like star RA: 15 52 56.31 Dec: 12 54 44.68 Magnitude: B = 16.0 P = 3. 12 h a detached close binary system consisting of a dwarf M star in a very close orbit around the hot white dwarf primary 0.535 M sun + 0.111 M sun i ~ 88°

18. NN Ser Discovered to be an eclipsing binary with an orbital period of ~3.12 hr by Haefner (1989). A preliminary analysis by Haefner (1989) indicated that NN Ser is a detached progenitor of a cataclysmic binary. Because of the large temperature difference between the hot white dwarf and the cool red dwarf star, the binary shows strong reflection effect that was investigated by Wood & Marsh (1991) with the IUE spectra, and the white dwarf temperature was determined. Brinkworth et al. (2006) reported that the orbital period of NN Ser decreased at a rate that was explained by angular momentum loss (AML) via magnetic braking (MB) of the fully convective component or the presence of a third body.

19. NN Ser Min.I = 2447344.52443 + 0.1300801969 E

20. V2051 Oph --- Dwarf Nova RA: 17 08 19.08 Dec: -25 48 31.7 Magnitude: B = 17.5 P = 3. 12 h V2051 Ophiuchi is adwarf nova, a sub-class of CVs comprised by low-mass transfer binaries showing recurrent outbursts

21. Information Observational site; Telescope; Terminal (e.g., CCD camera); ………….

22. 2.4m Telescope Location:100°1′ 52 ′ ′ (E), 26°42′ 02 ′ ′ (N) The highest point of GaoMeiGu observational station is 3242m, Relative height 800m Available nights: 210 Average seeing condition: 0.9" Sky background: V=21.54mag B=22.34mag Atmospheric extinction: V=0.135mag B=0.298mag

23. CCD image sensor EEV CCD36-40; scientific grade; MPP; back-illuminated; available with Unichrome UV-enhancement coating CCD format 1340 x 1300 imaging pixels; 20 x 20-μm pixels; 100% fill factor; 26.8 x 26.0-mm imaging area (optically centered) Grade Grade 1: 1 to 4 pixels ²40 dark defects, 5 to 8 pixels ²25 dark defects, 9 to 15 pixels 2 dark defects (max), ²5 column defects Linear full well (single pixel) 200,000 e- Linear full well (binned) 250,000 e- (high-sensitivity amplifier); 800,000 e- (high-capacity amplifier) Output amplifiersHigh-sensitivity or high-capacity amplifier; user selectable* User-selectable gains1/2x, 1x, 2x Read noise ²5 e- rms @ 100 kHz, 10 e- rms @ 1 MHz (high-sensitivity amplifier); ²10 e- rms @ 100 kHz, 20 e- rms @ 1 MHz (high-capacity amplifier) PICCD

24. Nonlinearity<2% NonlinearityNonuniformity Dynamic range16 bits Scan rate100 kHz; 1 MHz Frame readout <18 seconds for full frame @ 100 kHz; <1.8 seconds for full frame @ 1 MHz Dark current<0.5 e-/p/s @ -50°C; ²1 e-/p/hr @ -120°C Operating temperature 40°C with TEC (backfilled); -55°C with TEC (vacuum); -70 to -120°C with liquid nitrogen cooling Thermostating precision ±0.04°C over entire temperature range Liquid nitrogen hold time >25 hours PICCD performance

25. PICCD Quantum Efficiency

26. Information Properties of the objects at the observational site; When the objects rise and set; How far the objects from the Moon; How long can we observe them in one night), etc.

27. How to know your objects can be observed http://catserver.ing.iac.es/staralt/index.php

28. 1. Enter the date 2. Enter the longitude, Altitude and Highest point of observatory station 3. Enter the longitude and latitude of object E.g. IR Com 4. Press this button

29. Universal Time Local Time Sun Rise Twilight Altitude against Time Moon

30. Yes, you can input many star information in a time.

31. What we get from that? 1.When the objects rise and set; 2.How far the objects from the Moon; 3.How long can we observe them in one night, etc. The altitude of an object should be larger than 30 。

32. Information Star charts of the selected objects; How to get the Julian date of the observing day; How to Predict the time of mid- eclipse. ………….

33. Download the star map from CDS 1.http://aladin.u-strasbg.fr/aladin.gmlhttp://aladin.u-strasbg.fr/aladin.gml Maybe your system need to download something

34. Download Aladin.exe for Windows system

36. Files  Open 1. Enter the longitude and latitude of object E.g. IR Com 2. Press this button Many star maps

37. Object IR Com

38. Star map from the telescope CCD Star map from CDS

39. How to get the Julian date of the observing day http://aa.usno.navy.mil/data/docs/JulianDate.php

40. How to Predict the time of mid-eclipse We can work out when the mid-eclipsing time of IR Com happens today. (2455656.0- 2449486.4818691)/ 0.08703862787 =70882.53 2449486.4818691+ 0.08703862787*70882=2455655.953889 0.08703862787d= The mid-eclipsing time of IR Com: April 4, 2011: 18:54 April 4, 2011: 20:59 April 4, 2011: 23:04 April 5, 2011: 01:10 And so on The epoch of IR Com: HJD = 2449486.4818691 + 0.08703862787 E If you want to get the mid-eclipsing time, you can observed IR Com around these times.

41. Thank you

42. Practical exercises (DP leo, NN Ser) 1.When the objects rise and set on April 5, 2011; 2.How far the two objects from the Moon; 3.How long can we observe them on April 5, 2011. 4.Get the Julian date of April 5, 2011; 5.………..