Well looks like I have to unsubscribe from this group as the lastest clear sky app lists my location as a bortle class 5 now! Sure would have fooled me!
Bortle 7,8, and 9
Good to know about your Bortle classification.
Carole
Carole
I wouldn't necessarily trust an app to tell you your Bortle class, which was designed as a visual system. I have at times travelled only 10 miles and and gone from Bortle 7 to 5. A lot of the apps and maps don't have that level of granularity.
Here is the link for the original article by John Bortle: https://www.skyandtelescope.com/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/
Differentiating 7 from 5 is pretty easy:
In the summer, can you see the milky way (faintly) overhead from your location? That would make it Bortle 5. If you can only see the core than Bortle 6. If not at all then Bortle 7.
Clear skies, Nico
Here is the link for the original article by John Bortle: https://www.skyandtelescope.com/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/
Differentiating 7 from 5 is pretty easy:
In the summer, can you see the milky way (faintly) overhead from your location? That would make it Bortle 5. If you can only see the core than Bortle 6. If not at all then Bortle 7.
Clear skies, Nico
Helpful Insightful Respectful Concise
Nico Carver:
I wouldn't necessarily trust an app to tell you your Bortle class, which was designed as a visual system. I have at times travelled only 10 miles and and gone from Bortle 7 to 5. A lot of the apps and maps don't have that level of granularity.
Here is the link for the original article by John Bortle: https://www.skyandtelescope.com/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/
Differentiating 7 from 5 is pretty easy:
In the summer, can you see the milky way (faintly) overhead from your location? That would make it Bortle 5. If you can only see the core than Bortle 6. If not at all then Bortle 7.
Thanks for the explanation Nico!
My sky app states that I am in a Bortle 5 zone. I have a large school to the east and trees to the west. I haven't seen the Milky Way core in years.
I did see the MW core years ago, but only because I knew where it was. My wife could never see it.
I know that it is subjective, but I classify my skies as Bortle 7.
hello for everybody
my name Brian, from MIAMI FL USA . my SQM 16.84 ( real live reading )
my name Brian, from MIAMI FL USA . my SQM 16.84 ( real live reading )
Brian Diaz, what does SQM mean?
Greg
Greg
Brian Diaz:
hello for everybody
my name Brian, from MIAMI FL USA . my SQM 16.84 ( real live reading )
I will not complain about my skies again!
Your images are exceptional. Nice work!
Jim
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Hi Everyone,
My name is Ethan from CIBOLO TX USA . My SQM is 16.69.
My name is Ethan from CIBOLO TX USA . My SQM is 16.69.
I have seen it many times, but still need to know what SQM means!
Greg
Greg
HI
SQM ...A sky quality meter (SQM) is[b] [/b]an instrument used to measure the luminance of the night sky
with this meter you can measures the brightness of the night sky in magnitudes per square arcsecond.
so that meaning you can know your BORTLE in real time . following this table
sample : you go to some site and measure you reading , 20.55 following the table you are around BORTLE 5 real time
here is the link for more info and SQM reading meter ...http://www.unihedron.com/projects/darksky/
note :my backyard(Miami ,Fl) reading is sqm 16.84 as a show the image above
SQM ...A sky quality meter (SQM) is[b] [/b]an instrument used to measure the luminance of the night sky
with this meter you can measures the brightness of the night sky in magnitudes per square arcsecond.
so that meaning you can know your BORTLE in real time . following this table
sample : you go to some site and measure you reading , 20.55 following the table you are around BORTLE 5 real time
here is the link for more info and SQM reading meter ...http://www.unihedron.com/projects/darksky/
note :my backyard(Miami ,Fl) reading is sqm 16.84 as a show the image above
Thanks Brian!