深空乏層型CCD相機之極限星等分析;Limiting Magnitude Analysis for Deep Depletion CCD Camera

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/54117

Title:	深空乏層型CCD相機之極限星等分析;Limiting Magnitude Analysis for Deep Depletion CCD Camera
Authors:	黃如慧;Huang,Ru-huei
Contributors:	天文研究所
Keywords:	儀器特性;極限星等;instrument;CCD;limiting magnitude
Date:	2012-08-29
Issue Date:	2012-09-11 18:36:42 (UTC+8)
Publisher:	國立中央大學
Abstract:	從二十世紀後期，電荷耦合元件(Charge Coupled Device，CCD)成為可見光波段天文觀測中最主要使用的儀器。隨著半導體製成技術與時漸進日益成熟的提升下，增加CCD空乏層厚度，成功開發新一代的深空乏層型CCD。現今對於新儀器特性與效能表現的相關資訊尚不多見，因此，將對其更進一步地研究與評估。為了探討新儀器在特色及性能上的表現，利用極限星等與條紋圖案干擾程度來作為一審視指標。在觀測策略上，對兩張相同曝光秒數的影像連續拍攝，忽略觀測系統條件在拍攝期間任何的變動，並以測光較差的分析方式估計極限星等。並以光子計數的理論計算來作為檢測後續觀測結果品質的標準。由理論計算的結果中，在z’波段處，擁有較高量子效率的深空乏層型CCD相機比起傳統薄型CCD相機，極限星等的表現上更為優異，可達到0.4星等。且對深空乏層型CCD相機來說，理論計算與觀測的極限星等差距，隨波長增加而越趨遞少。探討應是由於大氣在波長逐漸增加的情況下，消光效應所造成的影響也愈漸減緩。因此，即使在天氣條件不甚理想的況狀下，選擇深空乏層型CCD相機，則還可進行較長波長i’、z’波段的觀測，其結果具備相當的可信度。而傳統薄型CCD相機在i’和z’波段的觀測影像，皆有條紋圖案的干擾情況，影像的背景起伏差異分別有2.9％及6.4％的變動程度。而深空乏層型CCD相機則不管在任何波段下，皆看不出有條紋圖案干擾情況的產生及影響。所以在較長波長i’、z’波段的觀測，挑選深空乏層型CCD相機作為觀測儀器，更能確保測光的準確性。Since the late twentieth century, the charge-coupled device becomes the most popular detector which is used in astronomical observations. As time goes on, the semiconductor process technology has developed more mature. The new generation deep depletion CCD has developed successfully as the thickness of the depletion layer is increased. It is insufficient for the related information of the characteristics and performance for new instrument. Therefore, we will research and evaluate further. In order to research the properties and ability of the new instrument, we use limiting magnitude and fringe pattern to as a reviewable indicator. In observational strategy, weuse the same exposure time to take two images continuously. Because the time interval of the two image is within very short time, we can ignore the changes of the sky condition,weather, and instrument during the acquisitions of pairs of images. Moreover, we use differential magnitudes method to estimate the limiting magnitude. And utilizing photoncounting to check quality of the observation.In the results of the theoretical calculation, limiting magnitude is better for deep depletion CCD which is possessed higher quantum efficiency than conventional thinned CCD at z’ band. The difference is about 0.4mag. And the difference of limiting magnitude between theoretical calculation and observation was getting less as wavelengthwas getting longer for deep depletion CCD. Due to the atmosphere at longer wavelength regions, the influence from extinction has reduced. Therefore, to use the deep depletionCCD camera, we can still observe at i’ and z’ band even on poor condition nights and also provide reliable results for observations. Besides, the fringe pattern causes 2.9% and6.4% photometric errors for the images acquired from conventional thinned CCD camera at i’ and z’ band. And we can not see the effect of fringe pattern in images from deepdepletion CCD camera at any band. Thus, to select deep depletion CCD camera as the observable instrument at i’ and z’ band, it can assure the photometric accuracy.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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