Thermal differential and image analysis of a fabricated 11-cm solar telescope using an active-passive cooling system

Date

4-2013

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Rogel Mari D Sese

Restrictions

Restricted: Not available to the general public. Access is available only after consultation with author/thesis adviser and only to those bound by the confidentiality agreement.

Abstract

Solar telescopes require specialized cooling systems to compensate for the intens solar radiation that affects its imaging performance. A temperature differential (ΔT) of at least ±2°C between the telescope mirror and ambient results in thermal currents that can potentially degrade the solar image. In this study, the effect of cooling system to the resulting quality of images captured using the 11-cm Newtonian optical tube assemblies tube assemblies (OTA) was determined. Two OTAs were designed and fabricated in which passive and active cooling systems were installed in one OTA (Active-Passive OTA) and no cooling system (Normal OTA) in the other. A microcontroller-based temperature monitor was also developed and used to determine the temperature profiles of the OTAs throughout the observation. Both OTAs were equipped with Baader white light solar filter and digital single lens reflex (DLSR) camera to simultaneously capture the full solar disk. After preprocessing, which utilized thresholding and solar disk detection, intensity gradient gradient and histogram methods were implemented to objectively compare the contrast of the images captured using the Normal OTA (set A) with the images captured using Active-Passive OTA (set B). Results showed that greater thermal differential (ΔT < 3.5°C) occurred in the Normal OTA than (ΔT < 1.5°C) in Active-Passive OTA. Moreover, a change in contrast (maximum of 280 pixel count) between pairs of images was measured suggesting that set B has higher contrast than set A. However, the actual blurring was not apparent in all images in set A to produce significant difference from set B. Therefore, active-passive cooling is effective at minimizing the thermal differential in 11-cm Newtonian OTA but it has small effect in improving the quality of solar images.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2013 P51 /D46

Document Type

Thesis

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