SLIKANJE DARK FRAME-ov (03.04.2006)
Naša skupina si je zadala nalogo:
- izmeriti temperaturno odvisnost temnega toka
- izmeriti odvisnost temnega toka od časa ekspozicije
Primerjava dark frame, ki smo ga naredili za celoten CCD čip (4096x4096) in za majhen kos čipa (512x512):
| IMAGE | MEAN | MIN | MAX |
| dark-10C_1s_512px.fits | 136.5 | 0. | 1128. |
| dark-10C_1s_4096px.fits | 136.6 | 0. | 1904. |
| dark-10C_5s_512px.fits | 135.7 | 0. | 458. |
| dark-10C_5s_4096px.fits | 136.7 | 0. | 6218. |
| dark-10C_10s_4096px.fits | 136.8 | 0. | 8816. |
| dark-10C_10s_512px.fits | 136.1 | 0. | 720. |
| dark-10C_30s_512px.fits | 136.6 | 0. | 1832. |
| dark-10C_30s_4096px.fits | 137.2 | 0. | 11976. |
| dark-10C_60s_512px.fits | 138.1 | 0. | 3400. |
| dark-10C_60s_4096px.fits | 138.6 | 0. | 16368. |
| dark-10C_120s_512px.fits | 139.8 | 0. | 6402. |
| dark-10C_120s_4096px.fits | 140.3 | 0. | 16368. |
| dark-10C_300s_512px.fits | 145.6 | 0. | 12868. |
| dark-10C_300s_4096px.fits | 145.7 | 0. | 16368. |
| dark-10C_600s_512px.fits | 153.8 | 0. | 16368. |
| dark-10C_600s_4096px.fits | 155.3 | 0. | 16368. |
ukaz: imstat *fits
ukaz: epar imstat
parametri:
PACKAGE = imutil
TASK = imstatistics
images = dark-10*40* List of input images
(fields = image,mean,stdev,min,max) Fields to be printed
(lower = INDEF) Lower limit for pixel values
(upper = INDEF) Upper limit for pixel values
(nclip = 0) Number of clipping iterations
(lsigma = 3.) Lower side clipping factor in sigma
(usigma = 3.) Upper side clipping factor in sigma
(binwidt= 0.1) Bin width of histogram in sigma
(format = yes) Format output and print column labels ?
(cache = no) Cache image in memory ?
(mode = ql)
izhod: ctrl d ali :q.
Iz te tabelice lahko vidimo, da je vseeno, ali delamo s celim čipom ali pa le z delom čipa (stolpec MEAN). Posledično se odločimo, da delamo z majhnim področjem čipa, ker je bralni čas precej manjši!
No ja potem smo se odločili, da vseeno delamo obe velikosti. S tem bomo res lahko preverili ali je vseeno ali ne.
Ekspozicije: 1s, 5s, 10s, 30s, 60s, 120s, 300s, 600s.
Najprej smo se lotili darkov pri temperaturi -10oC. Začeli smo z velikostjo čipa 512x512. Nato pa še z velikostjo 4096x4096. Na zgornji tabeli vidimo, da bolje za nas, da delamo z manjšo velikostjo, saj nebi bili radi tu celo noč.
Nato smo ohladili čip na -15°C. In spet iste čase ekspozicij.
Ocenjujemo, da temperatura ccd kamere niha z amplitudo približno 1°C.
Čip smo ohladili še na -20°C, -25°C in -30°C. Temperatura je nihala z amplitudo približno 1°C. Vse slikice smo posneli za velikost čipa 512x512, pri enakih ekspozicijah kot prej.
Podatki za ostale temperature
T = -15°C
| IMAGE | MEAN | STDV | MIN | MAX |
| dark-15C_1s_512px.fits | 150.3 | 106.1 | 0. | 16352. |
| dark-15C_5s_512px.fits | 136. | 6.34 | 0. | 328. |
| dark-15C_10s_512px.fits | 136.2 | 6.476 | 0. | 516. |
| dark-15C_30s_512px.fits | 136.5 | 8.312 | 0. | 1328. |
| dark-15C_60s_512px.fits | 137. | 12.18 | 0. | 2474. |
| dark-15C_120s_512px.fits | 138.5 | 21.04 | 0. | 4616. |
| dark-15C_300s_512px.fits | 141.5 | 45.31 | 0. | 9216. |
| dark-15C_600s_512px.fits | 148. | 88.97 | 0. | 15488. |
T = -20°C
| IMAGE | MEAN | STDV | MIN | MAX |
| dark-20C_1s_512px.fits | 134.9 | 6.387 | 0. | 164. |
| dark-20C_5s_512px.fits | 135.3 | 6.389 | 0. | 232. |
| dark-20C_10s_512px.fits | 135.6 | 6.44 | 0. | 368. |
| dark-20C_30s_512px.fits | 135.7 | 7.021 | 0. | 864. |
| dark-20C_60s_512px.fits | 136.3 | 9.277 | 0. | 1620. |
| dark-20C_120s_512px.fits | 137.1 | 14.02 | 0. | 2930. |
| dark-20C_300s_512px.fits | 139. | 30.06 | 0. | 6692. |
| dark-20C_600s_512px.fits | 152.7 | 122.7 | 0. | 16368. |
T = -25°C
| IMAGE | MEAN | STDV | MIN | MAX |
| dark-25C_1s_512px.fits | 140. | 36.05 | 0. | 7656. |
| dark-25C_5s_512px.fits | 135.4 | 6.37 | 0. | 212. |
| dark-25C_10s_512px.fits | 135.3 | 6.389 | 0. | 256. |
| dark-25C_30s_512px.fits | 135.6 | 6.573 | 0. | 548. |
| dark-25C_60s_512px.fits | 136.1 | 7.245 | 0. | 968. |
| dark-25C_120s_512px.fits | 136.5 | 9.998 | 0. | 1828. |
| dark-25C_300s_512px.fits | 138.2 | 22.01 | 0. | 4772. |
| dark-25C_600s_512px.fits | 140.3 | 39.22 | 0. | 8162. |
T = -30°C
| IMAGE | MEAN | STDV | MIN | MAX |
| dark-30C_1s_512px.fits | 138.7 | 29.07 | 0. | 6176. |
| dark-30C_5s_512px.fits | 135. | 6.377 | 0. | 168. |
| dark-30C_10s_512px.fits | 135.2 | 6.377 | 0. | 210. |
| dark-30C_30s_512px.fits | 135.7 | 6.431 | 0. | 404. |
| dark-30C_60s_512px.fits | 136. | 6.692 | 0. | 626. |
| dark-30C_120s_512px.fits | 136. | 7.909 | 0. | 1184. |
| dark-30C_300s_512px.fits | 136.5 | 14.1 | 0. | 2848. |
| dark-30C_600s_512px.fits | 138.3 | 25.77 | 0. | 5362. |
Slikica prikazuje povprečje elektronov na 100 px v koloni pri temperaturi -10°C in ekspoziciji 10 s.
Slikica prikazuje povprečje elektronov na 100 px v koloni pri temperaturi -25°C in ekspoziciji 10 s.
A
