分光观测及其数据处理

Pre-Extraction Reductions for CCD Data
1.
Examine a flat field exposure and determine the area of the chip that contains good data
implot good data & overscan regions
Hydrogen energy-level diagram
Excitation, de-excitation, ionization:
0.3762
Spectroscopy: The best way to determine the redshift of galaxy
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BzKs by VLT
观测式样:
Files k0116001-5 k0116006-10 k0116011-15 k0116016 k0116017 Obj. Bias Domeflat Skyflat HeAr HD19445 Btime Exp.(s) R.A. Dec. Epoch 16:30:00 0 16:32:00 90 17:00:00 3 18:40:00 30 18:50:15 60 03:08:26 26:20:35 2000
Domeflat
Skyflat
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Standards
HeAr
Object
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6.3 光谱处理 IRAF简介

IRAF is the Image Reduction and Analysis Facility

a general purpose software system for the reduction and analysis of astronomical data

Extracting the Comparison Exposures apall
Determinating the Dispersion Solution identify

在定标灯光谱上选取一些3或4条发射线，标定波长 拟合给出波长和pix的对应关系，d可以删除错误点 多次重复，给出最终波长与pix的关系（ Dispersion Solutions ）

输入：
台站位置 观测日期 天体位置


输出： 最佳观测时间
6.2 光谱观测

仪器设置：
************************************* Observer:Kong Xu Institute:USTC Night Assistant:Jia Junjun Date:2008-01-06 --------------------------------------------------------------------------------Seeing:2.0", Temp:-5C, RH:30%, Weather:Clear Grating:200lp/mm,Blazed at:5500A,Order:1,Slit:2.2" OMR CCD GAIN :2.25 RON:2.64E -----------+------------+--------+-------+-----------+------------+-------+-
2. 3. 4.
Load ccdred and run setinstrument specphot Combine the bias frame zerocombine Create a perfect normalized illumination corrected flate-field exposure.
02:27:17
02:27:17 02:27:17 03:08:26
33:34:45
33:34:45 33:34:45 26:20:35
2000
2000 2000 2000
证认图：NED http://nedwww.ipac.caltech.edu/


名称
位置


红化
文献


图像
星等 …
Bias

Assigning the Dispersion Solutions to the Object Exposure dispcor
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Flux Calibration

Correct the airmasses to midexposure by running the setairmass routine Establish the correct subdirectory for the standard star observations in the parameter file of the package Establish the correct file to use for extinction correction of your data

http://iraf.noao.edu/

初始化：mkiraf login.cl、 uparm/ 登陆退出：cl；logout 在线帮助：help splot ；help display 参数设置：epar；lpar 显示图象：display *.fits or display *.imh 格式转化：rfits；wfits
Background=fit weights=variances clean=yes saturation=32400 …

Parameters Controlling The Output Format
Format=multispec extras=yes
Parameters Controlling the Extraction Aperture
line=INDEF nsum=10 width=10 lower=-5 upper=5 resize=no
Parameters Controlling the Background Windows
B_sample=-20:-8,8:20 b_naver=-100 b_funct=chebyshev b_order=2
1. 2.
Find the spectrum ：display; implot Define the extraction window and the background windows Trace the center of spatial profile as a function of the dispersion axis Sum the spectrum within the extraction window, subtracting sky




For each standard star observation execute the task standard
The sensfunc task will allow you to interactively fit the sensitivity function as a function of wavelength using the output file from standard The sensitivity function determined by sensfunc is applied to your data by the calibrate task
第六章 分光观测及其数据处理
6.1 观测准备：申请时间、观测源 6.2 光谱观测：仪器设置，时间计算 6.3 光谱处理：bias、flat、obj. standards、HeAr… 6.4 星系红移的确定：redshift、rest frame 6.5 谱线特征的测量：F、prof.、EW、FWHM 6.6 恒星连续谱测定：一级标准星、二级、…
6.1 观测准备

观测申请：
项目名称 科学内容：大量阅读文献

课题的科学意义 + 望远镜的观测能力 观测时间：月份和月相（有月夜、无月夜，灰夜） 最近成果：paper list 仪器要求：折轴、卡焦、BFOSC 观测对象：list

观测工具
观测时间的计算：望远镜webpage proas
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Parameters Controlling the Trace
t_nsum=10 t_step=10 t_funct=spline3 t_niter=1
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Finnal extracted spectrum
Wavelength Calibration
k0116018
k0116019 k0116020 k0116022 。。。 k0116041-45 k0116046-50
来自百度文库
NGC0925
NGC0925 NGC0925 HD19445 Domeflat Bias
19:54:24 1800
20:26:16 1800 20:56:38 1800 22:19:08 60 30:21:00 120 30:25:00 0

Extracting the Spectrum : apall Parameters:

Parameters Controlling the Extraction Aperture
line=INDEF nsum=10 width=10 lower=-5 upper=5 resize=no

Parameters Controlling the Background Windows

The final extracted flux-calibrated spectrum
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Dealing with Multiple Stars On the Slit
6.4 星系红移的确定
obs em z em
Spectral Lines - Doppler
B_sample=-20:-8,8:20 b_naver=-100 b_funct=chebyshev b_order=2

Parameters Controlling the Trace
t_nsum=10 t_step=10 t_funct=spline3 t_niter=1

Parameters Controlling the Summation and Background Subtraction
3.
4.
5. 6.
Wavelength Calibration
Flux Calibration
Characterizing Your Data


imhead *.fits ds9 *.fits implot *.fits :c 500 :l 500; …
Parameters for Extraction in apall
obs em z em
谱线红移：当天体离开我们时，天体光谱中的谱线都向光谱的 红端位移，波长变长(红移)；当天体接近我们时，谱线向光谱的 紫端位移，波长变短(蓝移)。
观测坐标系 静止坐标系：红移校正
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Doppler Examples
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L ε L δL γLβL α
flatcombine response ccdproc illum imarrith
5.
Process all of the rest of your data through ccdproc using perfectFlat for your flat ccdproc
Extraction and Calibration Overview

Proas: planning of astronomical observations

Proas：a program devoted to the computation of the visibility conditions of astronomical objects.
http://www.ucm.es/info/Astrof/software/proas/proas.html