Comment on what you estimate is your measurement accuracy. How many significant figures are meaningful? (In other words, can you measure the diameter to an accuracy of one pixel? One tenth of a pixel? One hundredth of a pixel? None of these?)
How much fainter in DN units is the sunspot than its surroundings?
Repeat your measurement of the Sun’s diameter several times and post your average value of the diameter in kilometers on the Blog. Include a comment about sig figs.
Describe the general nature of the sun's surface around the location of this sunspot.
1)Max DN value that I could measure; x=699, y=636, value=4779.00
ReplyDelete2)We can measure up to 100th of a pixel. The last digit will be the guess. So there are 6 sig figs; 4796.584
3)DN value for the sun spot was 2801.00. And it is approximately 2000 less than my max. Around the sunspot DN value is changing but it is definitely smaller on the sunspot.
4)The average of the diameter is 967 pixels. Average diameter is 1389927.391km.
However, since the known value (1,392,000km) has only 4 sig figs, the average needs to be rounded in order to have 4 sig figs. So the final answer for the average will be 1,3900,000km. In this number it looks like there are only three sig figs but the first zero (red one) is significant. The number on the tenth thousand place will include the guess on our measurement.
5)Around the sunspot, there is a really bright area on its left which has DN value of roughly 5000, on the sunspot it drops to 2600. On other points it is around 4000. The light coming from the sunspot is less than its surrounding therefore Sunspot is cooler. The light coming from the convection envelope is redirected by Sun`s magnetic field and causes the light to cool down which causes sunspots.
The largest value of DN is 5360 at x =741 and y=783 (white spot of the sun's surface)
ReplyDeleteThe greater the number of significant figures the more precise is the measurement. Since we are just estimating the diameter of the sun..my significant figure is up to one pixel. My diameter for the sun is 13,900,000 km.
In the sunspot, the value of the DN is 2655. It is almost half of the brightest part of the sun which has a DN equal to 5360
Sunspots are a cool dark spots around the sun. This is where solar falres occur.
Using the imageJ and relating to the values of DN, I can see that brightest parts of the sun are near the sunspot
1) The largest DN value I could find was 5129, located at x = 1032, y = 540. There is also a DN value of 5128 at x = 765, y = 789
ReplyDelete2) My length measurement came out to be 960.005 pixels. I notice that as I slowly move the cursor, ImageJ changes in increments of 3 pixels. I believe than that this is the minimum amount of uncertainty in the measurement. In repeating the measurement several times, I often got values that were within 3 pixels of each other, but occasionally there were values outside of that range. The measurement is limited by starting and ending the measurement with the “true” pixel where the sun’s edge is located, and taking the actually measuring the full diameter (widest section) of the sun with the cursor. Overall, I would report an uncertainty of plus or minus 10 pixels.
3) The sunspot has a DN value of 2655, which is roughly 60% the brightness of the surroundings
4) My average measurement for the diameter (pre significant figures) of the sun was 1392156.196 km. In looking at the distribution of my measurements, I was as much as 300 km above the average and 150 km below the average. I would report the diameter as 1392000 km plus or minus 200 km.
5) The area surrounding the sunspot is very bright, while the sunspot is very dark, since it is cooler.
Has anyone considered how many pixels the earth would cover in this image, if it were at the distance of the sun? Earth diameter is 12,715 km
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ReplyDeleteMy diameter for the sun is 1,390,000 km
ReplyDeleteThe largest DN value I found is 5572 located at (739,781)which is at the white spot of the sun's surface
ReplyDeleteThe Sunspot has a lowest DN of 2655 at (777,789)which is located near the white spot. The sunspot is half the DN value of the white spot.
Is it possible that the white spots in the image are solar flares???
After a series of measurement of the sun's diameter. I obtained a mean value of 1390028.083 km. Since I just did an approximation, my diameter for the sun will be reported to 3 SF and it is equal to 1390000 km.
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ReplyDeletethe earth would cover around 10 pixels if the distance is the same with the sun.
ReplyDeleteSet: 649 to 4702
ReplyDeleteLargest DN number: 5214
Average Diameter: 965.145
The significant figures of this number would seem to be the nearest whole number as that is where the consistency of the measurements starts to vary. The other numbers vary too much for them to be accurate representations of the measurement.
Scale: 0.000694 pixels/km
Low DN @ sunspot = 2700 (roughly 1000 less than the surroundings)
The sunspot is dark but the area directly surrounding it is lighter than the area of the sun.
The largest DN value I got is 5572 at X=739 and Y= 781. This point is located in the "white spot" of the sun's surface.
ReplyDeleteMy approximate diameter is accurate up to one pixel. Since we are just getting the approximate value of the diameter of the sun, we can only used 3 significant figures. After a series of measurements. I got a mean diamter of 1390158.334 km and my approximate diameter of the sun is 1390000 km.
I zoomed the sunspot up to 800% to get the minimum DN. The sunspot has a 2655 DN value and comparing it to the white spot of the sun's surface, the sunspots is around 3000 DN lesser to the white spot.
A sunspot is a spot on the Sun's surface (photosphere) that is cooler and darker than the surrounding area.
The darkest DN value that I measured was 2959 (776,788). The brightest was 5559 (740,780). The difference in brightness around the sunspot v.s. the area around it was about 1000 pixels.
ReplyDeleteAlthough the measurement was made in pixels out to the thousandths place, I would not elect this place to be the correct number of significant figures because when I move my cursor over the sun, the pixels change from 2-6 pixels for the smallest movement. Therefore I would say that my level of significance is +/- 3 pixels.
The average diameter in pixels was 955 +/-3 pixels. I got a mean diameter of the sun when setting the scale of 1894869 km which seems a little high with +/- 20000?
The area of the sun around this sunspot seems uniform in texture (temperature), while the sunspot is very non-uniform.
I got the highest DN of 5559 on the white sppot of the sun's surface at x=740 and y=780. The lowest DN value of 2655 can be located on the black spot of the sun's surface at x=777 and y=789. The sunspots are darker and cooler regions of the sun's surface. I noticed that the white spot and dark spot were near each other. The sunspot is almost haf fainter than the white spot.
ReplyDeleteI got a diameter measurement of 138981.562 km (almost 1064 pixels). I only estimated the edge of the two points of the circle and therefore I should only used 3SF to report the diameter of the sun. Since my measurement were definitely approximations my diamter will be 1390000 km. My measurement is not accurate to +/- 10 pixels or 1000 km.
The largest DN value I got is 5559 located on the white part of the sun’s photosphere. The lowest DN value I got is 2655 located at the sunspot. This is 2904 DN difference. The white spot is located near the sunspot. These sunspots are cooler and darker region of the sun’s photosphere. The temperature is approximately between 3000K to 4000K.
ReplyDeleteMy measurement should be accurate up to 1 pixel. I got a measurement of 1392458.227 km. My measurement must be in 3 significant figures since I am just doing an approximation. My measurement depends on the accuracy of finding the real edge of the image. I need to zoom up 600% to locate the real edge of the circle. My approximate diameter of the sun is 13900000 km.
The brightest DN value that I found is 5581 t x = 739 and y = 780. The lowest DN value of 2655 in the images was located in the sunspot at x= 777 and y =789.
ReplyDeleteI measured the diameter of the sun 5 times by zooming in and locate the edge of the limb then zooming out. I used a ruler to locate the exact diameter (exact half). From the 5 measurements, my average diameter of the sun is 1392255.964 km (1095 pixels). My measurement is just an approximation so I decided to report my measurement up to 3 SF. My diameter is 1390000 km.
The sunspot is the dark spot and cooler part of the sun. Comparing the maximum and minimum DN. I can say that sunspot is almost 50% fainter than the brightest part of the sun's surface
Item 2: The greatest DN value was 5192 at x=1033 y=539. I found this value after zooming into the area which appeared the brightest.
ReplyDeleteItem 3 & 5: A pixel could be a measure or a count. ImageJ counts pixels. Each pixel has a coordinate (x,y). The pixel represents a value of light in a CCD camera that comes from an area. It becomes a measure when we set a scale to the pixel. A fraction of a pixel is a mathematical operation. After setting the scale, I calculated that one pixel represents 1,445.0861 km. To four significant digits, this number is 1445 km per pixel. The average pixels in the diameter is 963 pixels. The bottom line is that all measurements should have 4 significant digits.
Item 4 The miminum DN was 2697. It was flanked by DN's of 4362 and 4497. The image formed a valley like the Grand Canyon.
Item 6 I created a surface plot of the area around the Sun spot. The area consisted of a bright spot and a dark spot. Bright streams lead from the dark spot to the bright spot.
The color table was set to fire and the image appeared like those on the internet showing Sun spots. The Sun spot was red and the bright spot was white.
The largest DN value I found was 5581 at (739,780). This was located in the white spot of the sun’s surface. The lowest DN Value I found was 2655 and was located in the sunspot. The sunspot is a darker area as compared to the surroundings of the sun’s surface. This is nearly 50% fainter than the white spot
ReplyDeleteThe average diameter of the Sun I measured was 963 pixels. The main problem lies in determining the real edge of the sun. I zoomed in the image to get the actual edge of the sun then I used a protractor to measure the real half of the circle. Since we were just getting the approximate value of the diameter, my measurement will have 3 significant figures. My diameter will be 1390000 km.
The largest DN value = 5559 located at x=740 and y=780. I measured the diameter of the sun 4 times. My measurements ranged from 960 to 964 pixels. Since the number in the ones place value (and smaller) varied, I would say that I could only be accurate to the nearest tens place value whih would be 960 pixels. This is 2 sig figs. So I can only be accurate to the nearest 10 pixels.
ReplyDeleteThe Sunspot had a DN value of 2801 which was more than 1200 DN less than the surrounding area which was greater than 4000 DN.
I measured the sun diameter in km 5 times. I could only be accurate to 139,000km. The 100 place value varied for each measurement.
When I enlarged the image to 300 times, there appeared to be lines radiating out from the center of the sun spot.