3:30 PM - 5:00 PM
[O08-P57] Research on the color of the shadow of the earth at the lunar eclipse on Nov.19,2021
Keywords:lunar eclipse, turquoise fringe
Summary
We photometrically measured the images of a lunar eclipse with the pattern erased, and from the results we found the color of the turquoise fringe in terms of R(red),G(green)and B(blue) ratios.
1. Introduction
We observed the lunar eclipse that occurred on November 19 using a CMOS camera and a digital SLR camera. We then decided to stude the light intensity distribution of R(red), V(vision) and B(blue) in the main shadow. In this lunar eclipse, the "turquoise fringe", a phenomenon in which red light is absorbed when sunlight passes through the stratosphere and only blue liht travels straight ahead, was alse observer at our school. We examined this relationship between the light intesity of R, V and B.
2.Method
Location: Ichinomiya High School (6-9 Kitazono-dore, Ichinomiya, Aichi)
Equipment: ZWO ASI-290MM, R,V,B filters, Takahashi FSQ-106 (D:106mm f:530mm), EM200 equatorial mount, Canon EOS RP EF200mmF2.8 2X extender
Observation date: November 19,2021
Software: Subaru image, processing software Makalii, Stellar Image ver.6,8, Stellar Navigator ver.11, Microsoft Excel 2019
Photometry: We eliminated the lunar pattern by primary processing of the CMOS camera image and by dividing the change in brightness due to the lunar pattern in the image by the full moon image after the end of the lunar eclipse. We then apertured about 20 points of the moon image where the pattern disappeared at a radius of 5 (Figure 1). We examined the angular distance between the metered point and the center of the main shadow and the Obj average, converted it to a 1-second exposure, and created a graph (scatter plot) using spreadsheet software.
3. Results and Discussion
The graphs (scatter plots) are shown with the angular distance from the main shadow center on the horizontal axis and the brightness equivalent to a 1-second exposure for R, V, and B on the vertical axis (logarithmic axis). (Figure 2)
From the graph, it can be seen that the brightness inside the main shadow is R>V>B, indicating a red color. This is due to the fact that blue and green light are more scattered as sunlight passes through the earth's atmosphere. However, V and B are sharply elevated from the edge of the main shadow to the half-shadow. (abscissa 43'-47')This result suggests that the turquoise fringe was observed.
4. prospects in the future
Since the distribution of data of V and B is large, we would like to reduce the distribution by removing data that statistically corresponds to outliers. We would also like to create a schematic diagram of the colors of the main shadow and the turquoise fringe by synthesizing the colors with the ratio of RVB for every two minutes of angular distance.
We photometrically measured the images of a lunar eclipse with the pattern erased, and from the results we found the color of the turquoise fringe in terms of R(red),G(green)and B(blue) ratios.
1. Introduction
We observed the lunar eclipse that occurred on November 19 using a CMOS camera and a digital SLR camera. We then decided to stude the light intensity distribution of R(red), V(vision) and B(blue) in the main shadow. In this lunar eclipse, the "turquoise fringe", a phenomenon in which red light is absorbed when sunlight passes through the stratosphere and only blue liht travels straight ahead, was alse observer at our school. We examined this relationship between the light intesity of R, V and B.
2.Method
Location: Ichinomiya High School (6-9 Kitazono-dore, Ichinomiya, Aichi)
Equipment: ZWO ASI-290MM, R,V,B filters, Takahashi FSQ-106 (D:106mm f:530mm), EM200 equatorial mount, Canon EOS RP EF200mmF2.8 2X extender
Observation date: November 19,2021
Software: Subaru image, processing software Makalii, Stellar Image ver.6,8, Stellar Navigator ver.11, Microsoft Excel 2019
Photometry: We eliminated the lunar pattern by primary processing of the CMOS camera image and by dividing the change in brightness due to the lunar pattern in the image by the full moon image after the end of the lunar eclipse. We then apertured about 20 points of the moon image where the pattern disappeared at a radius of 5 (Figure 1). We examined the angular distance between the metered point and the center of the main shadow and the Obj average, converted it to a 1-second exposure, and created a graph (scatter plot) using spreadsheet software.
3. Results and Discussion
The graphs (scatter plots) are shown with the angular distance from the main shadow center on the horizontal axis and the brightness equivalent to a 1-second exposure for R, V, and B on the vertical axis (logarithmic axis). (Figure 2)
From the graph, it can be seen that the brightness inside the main shadow is R>V>B, indicating a red color. This is due to the fact that blue and green light are more scattered as sunlight passes through the earth's atmosphere. However, V and B are sharply elevated from the edge of the main shadow to the half-shadow. (abscissa 43'-47')This result suggests that the turquoise fringe was observed.
4. prospects in the future
Since the distribution of data of V and B is large, we would like to reduce the distribution by removing data that statistically corresponds to outliers. We would also like to create a schematic diagram of the colors of the main shadow and the turquoise fringe by synthesizing the colors with the ratio of RVB for every two minutes of angular distance.