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Article SOLAR SPOTS. Page 1 of 4 →
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Solar Spots.
SOLAR SPOTS .
THOUGH those singular appearances , termed spots on the sun , are said to be very seldom so large as to be visible to the naked eye , I have had the opportunity of so observing several , since my notice of the remarkable one seen on the 25 th of January last . Hence I am inclined to conclude , that they have been unusually large of late . Of the rarity of such occurrences , Dr . Dick , in particular , a living astronomical writer , author of " The Sidereal Heavens" " Practical Astronomy" & c . testifies
, , in the following remarks ( which I partially quoted in my last communication , ) appended as a foot-note to "Barrit ' s Astronomy . " "I have for many years examined the solar spots with considerable minuteness , and have several times seen spots which were not less than the onetwenty-fifth part of the sun ' s diameter , which would make them about 35 , 200 miles in diameter ; yet they were visible neither to the naked eye nor through an opera lass magnifing about three times .
Andthereg y , fore , if any spots have been visible to the naked eye , which we must believe , unless we refuse respectable testimony , they could not have been much less than 50 , 000 miles in diameter . " The writer of the above , having thus never been able to detect a spot , or group of spots , with the unaided eye , although a frequent and scientific observer , I must consider myself fortunate in having seen the following distinct spots , since the one which I ventured to describe iu January
last . On the 21 st of March , I observed a spot a little before sun-set , a few degrees S . E . of the sun ' s centre . It was just perceptible , though of course of very considerable size , according to Dr . Dick ' s inference . May 13 . —I observed another , which had come on the sun ' s eastern
limb about six days before , and with a power of about 200 , was resolved into a vast cluster of spots of different dimensions , all connected together . The whole formed one round spot to the naked eye . June 8 . —A long cluster , somewhat like a shepherd ' s crook , appeared as one spot to the unassisted eye . It was then past the middle of its course , having a south declination . June 24 and 25 —A very long , narrow , string of spots was discernible ,
presenting to the naked eye a slightly oblong appearance , the effect of its enormous extent . I counted 60 constituent spots of all sizes , mostly small . This chain measured upwards of a digit , or above one twelfth part of the solar diameter . Perhaps 76 thousand miles might be about its stretch . It resembled very much a flight of wild geese . July 7 and 10 , respectively . —Another elongated cluster was visible to the naked eyeand to which my attention was particularldirectedb
, y , y . a paragraph in a newspaper of the 7 th , stating , that it had just appeared on the eastern margin of the sun , and on Tuesday morning , was proceeding , I presume , towards the centre of the disc . " The spots visible at present , " says the writer , "form a long narrow cluster , in which are upwards of thirty spots , many of which seem to be running into each other , and are all surrounded by one common penumbra . It will probably appear much larger and denser as it comes more to the centre .
The size at present is as follows : —Total length , 140 , 000 miles , or 5 £ times the circumference of the earth ; breadth , about 20 , 000 miles , but the breadth varies considerably : length of the thickest part , or that which appears to be one spot under a low power , 95 , 000 miles . " Having examined this spot attentively through the telescope , when it had more advanced to the sun ' s centre , than at the time the writer of the
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
Solar Spots.
SOLAR SPOTS .
THOUGH those singular appearances , termed spots on the sun , are said to be very seldom so large as to be visible to the naked eye , I have had the opportunity of so observing several , since my notice of the remarkable one seen on the 25 th of January last . Hence I am inclined to conclude , that they have been unusually large of late . Of the rarity of such occurrences , Dr . Dick , in particular , a living astronomical writer , author of " The Sidereal Heavens" " Practical Astronomy" & c . testifies
, , in the following remarks ( which I partially quoted in my last communication , ) appended as a foot-note to "Barrit ' s Astronomy . " "I have for many years examined the solar spots with considerable minuteness , and have several times seen spots which were not less than the onetwenty-fifth part of the sun ' s diameter , which would make them about 35 , 200 miles in diameter ; yet they were visible neither to the naked eye nor through an opera lass magnifing about three times .
Andthereg y , fore , if any spots have been visible to the naked eye , which we must believe , unless we refuse respectable testimony , they could not have been much less than 50 , 000 miles in diameter . " The writer of the above , having thus never been able to detect a spot , or group of spots , with the unaided eye , although a frequent and scientific observer , I must consider myself fortunate in having seen the following distinct spots , since the one which I ventured to describe iu January
last . On the 21 st of March , I observed a spot a little before sun-set , a few degrees S . E . of the sun ' s centre . It was just perceptible , though of course of very considerable size , according to Dr . Dick ' s inference . May 13 . —I observed another , which had come on the sun ' s eastern
limb about six days before , and with a power of about 200 , was resolved into a vast cluster of spots of different dimensions , all connected together . The whole formed one round spot to the naked eye . June 8 . —A long cluster , somewhat like a shepherd ' s crook , appeared as one spot to the unassisted eye . It was then past the middle of its course , having a south declination . June 24 and 25 —A very long , narrow , string of spots was discernible ,
presenting to the naked eye a slightly oblong appearance , the effect of its enormous extent . I counted 60 constituent spots of all sizes , mostly small . This chain measured upwards of a digit , or above one twelfth part of the solar diameter . Perhaps 76 thousand miles might be about its stretch . It resembled very much a flight of wild geese . July 7 and 10 , respectively . —Another elongated cluster was visible to the naked eyeand to which my attention was particularldirectedb
, y , y . a paragraph in a newspaper of the 7 th , stating , that it had just appeared on the eastern margin of the sun , and on Tuesday morning , was proceeding , I presume , towards the centre of the disc . " The spots visible at present , " says the writer , "form a long narrow cluster , in which are upwards of thirty spots , many of which seem to be running into each other , and are all surrounded by one common penumbra . It will probably appear much larger and denser as it comes more to the centre .
The size at present is as follows : —Total length , 140 , 000 miles , or 5 £ times the circumference of the earth ; breadth , about 20 , 000 miles , but the breadth varies considerably : length of the thickest part , or that which appears to be one spot under a low power , 95 , 000 miles . " Having examined this spot attentively through the telescope , when it had more advanced to the sun ' s centre , than at the time the writer of the