Adding Seeing and Transparency To Sketches


Forrest Erickson
 

Attached is the sketching sheet I have been using at star parties in one form or another for some years. One of my most recent changes was to add a note to capture Seeing and Transparency. This caused a problem because I could not remember how the rating system worked once I was under the sky and I could not explain it well to persons sketching sun spots at the Blount County Public Library.

So this morning I went to the Astronomical League web page for the definitions  (here: https://www.astroleague.org/content/seeing-and-transparency-guide) which are below.

I guess I will have to make an eleventh version of the document soon.

Suggestions for formatting and otherwise doing so would be of help.

Lee


Seeing and Transparency Guide

Introduction

Seeing and Transparency are values that an observer uses to compare the quality of the sky from night to night.  The values are very specific to an individual observer's visual acuity.  Seeing is a measure of how stable the sky is.  Transparency is a measure of how clear the sky is. Most of the Astronomical League's Observing Programs require the observer to evaluate these conditions for each observation and to record them in their observation log.


Here are two scales that are acceptable for all Observing Programs.  They are simple to use and require no special equipment.  Both of these values can be done very formally using special equipment, but for the AL Observing Programs this level of effort is not required.

Seeing:  How stable is the sky?​

  • E (excellent) - The brighter stars are not twinkling at all.
  • VG (very good) - The stars are twinkling slightly, but the brighter planets are not twinkling.
  • G (good) - The brighter planets are twinkling slightly.
  • F (fair) - The brighter planets are obviously twinkling.
  • P (poor) - The atmosphere is turbulent.  all objects are twinkling to the points where observation is not practical.
Transparency:  How clear is the sky?​​

Transparency is a measure of what you can see in the nighttime sky in spite of dust, smoke, haze, humidity, or light pollution.  An easy way to measure this is to use the magnitude of the faintest star you can see.  Ideally, this would be looking straight up at zenith.  But, to make life simpler, you can use the Little Dipper (Ursa Minor) if you can see it.  Here is the scale.

  • 1 - If you can't see Polaris.
  • 2 - If you can only see Polaris.
  • 3 - If you can see the two stars on the end of the bowl of the Little Dipper (Kochab and Pherkad).
  • 4 - If you can see any of the stars in the handle of the Little Dipper.
  • 5 - If you can see 6 of the 7 stars in the Little Dipper.
  • 6 - If you can see all 7 stars in the Little Dipper.
  • 7 - If you can see stars near the Little Dipper that are not part of the stick figure.  (I envy your young eyes...)
Although atmospheric extinction will vary from season to season, and from latitude to latitude, using the Little Dipper is a simple and reasonable solution.


James Cantu
 

Lee, I'm happy to help format/craft revisions. I'll take a shot at this week. 

Best regards, 
James 

On Sat, Oct 15, 2022 at 8:28 AM Forrest Erickson <forresterickson@...> wrote:
Attached is the sketching sheet I have been using at star parties in one form or another for some years. One of my most recent changes was to add a note to capture Seeing and Transparency. This caused a problem because I could not remember how the rating system worked once I was under the sky and I could not explain it well to persons sketching sun spots at the Blount County Public Library.

So this morning I went to the Astronomical League web page for the definitions  (here: https://www.astroleague.org/content/seeing-and-transparency-guide) which are below.

I guess I will have to make an eleventh version of the document soon.

Suggestions for formatting and otherwise doing so would be of help.

Lee


Seeing and Transparency Guide

Introduction

Seeing and Transparency are values that an observer uses to compare the quality of the sky from night to night.  The values are very specific to an individual observer's visual acuity.  Seeing is a measure of how stable the sky is.  Transparency is a measure of how clear the sky is. Most of the Astronomical League's Observing Programs require the observer to evaluate these conditions for each observation and to record them in their observation log.


Here are two scales that are acceptable for all Observing Programs.  They are simple to use and require no special equipment.  Both of these values can be done very formally using special equipment, but for the AL Observing Programs this level of effort is not required.

Seeing:  How stable is the sky?​

  • E (excellent) - The brighter stars are not twinkling at all.
  • VG (very good) - The stars are twinkling slightly, but the brighter planets are not twinkling.
  • G (good) - The brighter planets are twinkling slightly.
  • F (fair) - The brighter planets are obviously twinkling.
  • P (poor) - The atmosphere is turbulent.  all objects are twinkling to the points where observation is not practical.
Transparency:  How clear is the sky?​​

Transparency is a measure of what you can see in the nighttime sky in spite of dust, smoke, haze, humidity, or light pollution.  An easy way to measure this is to use the magnitude of the faintest star you can see.  Ideally, this would be looking straight up at zenith.  But, to make life simpler, you can use the Little Dipper (Ursa Minor) if you can see it.  Here is the scale.

  • 1 - If you can't see Polaris.
  • 2 - If you can only see Polaris.
  • 3 - If you can see the two stars on the end of the bowl of the Little Dipper (Kochab and Pherkad).
  • 4 - If you can see any of the stars in the handle of the Little Dipper.
  • 5 - If you can see 6 of the 7 stars in the Little Dipper.
  • 6 - If you can see all 7 stars in the Little Dipper.
  • 7 - If you can see stars near the Little Dipper that are not part of the stick figure.  (I envy your young eyes...)
Although atmospheric extinction will vary from season to season, and from latitude to latitude, using the Little Dipper is a simple and reasonable solution.



--
James M. Cantu


David Fields
 



Suggestions for formatting and otherwise doing so would be of help.

Hi Lee,
Your measure of noting sky transparency is good, provided Ursa Minor is not in a 'special' region of the sky (overly light-polluted or overly dark).  My only suggestion is that you incorporate a note about the Bortle scale, or mention the nice smartphone apps that are available at no charge.  I wrote up all this for this month's Trapezium (ORION newsletter), and will attach the newsletter.. 

My guess is that you'll receive the attachment but that the mail server might not include it.  Anyone wanting to be on the list to receive the Trapezium can signup at groups.io, or send me their email address.

Tonight's ORION meeting is at the Roane State, Oak Ridge Campus at 7 PM -- everyone welcome.

Cheers,
David


-----Original Message-----
From: Forrest Erickson <forresterickson@...>
To: SmokyMountainAstronomicalAssociationGroupsIO SMAS <smokymtnastro@groups.io>
Sent: Sat, Oct 15, 2022 8:28 am
Subject: [smokymtnastro] Adding Seeing and Transparency To Sketches

Attached is the sketching sheet I have been using at star parties in one form or another for some years. One of my most recent changes was to add a note to capture Seeing and Transparency. This caused a problem because I could not remember how the rating system worked once I was under the sky and I could not explain it well to persons sketching sun spots at the Blount County Public Library.

So this morning I went to the Astronomical League web page for the definitions  (here: https://www.astroleague.org/content/seeing-and-transparency-guide) which are below.

I guess I will have to make an eleventh version of the document soon.

Suggestions for formatting and otherwise doing so would be of help.

Lee


Seeing and Transparency Guide

Introduction

Seeing and Transparency are values that an observer uses to compare the quality of the sky from night to night.  The values are very specific to an individual observer's visual acuity.  Seeing is a measure of how stable the sky is.  Transparency is a measure of how clear the sky is. Most of the Astronomical League's Observing Programs require the observer to evaluate these conditions for each observation and to record them in their observation log.


Here are two scales that are acceptable for all Observing Programs.  They are simple to use and require no special equipment.  Both of these values can be done very formally using special equipment, but for the AL Observing Programs this level of effort is not required.

Seeing:  How stable is the sky?​

  • E (excellent) - The brighter stars are not twinkling at all.
  • VG (very good) - The stars are twinkling slightly, but the brighter planets are not twinkling.
  • G (good) - The brighter planets are twinkling slightly.
  • F (fair) - The brighter planets are obviously twinkling.
  • P (poor) - The atmosphere is turbulent.  all objects are twinkling to the points where observation is not practical.
Transparency:  How clear is the sky?​​

Transparency is a measure of what you can see in the nighttime sky in spite of dust, smoke, haze, humidity, or light pollution.  An easy way to measure this is to use the magnitude of the faintest star you can see.  Ideally, this would be looking straight up at zenith.  But, to make life simpler, you can use the Little Dipper (Ursa Minor) if you can see it.  Here is the scale.

  • 1 - If you can't see Polaris.
  • 2 - If you can only see Polaris.
  • 3 - If you can see the two stars on the end of the bowl of the Little Dipper (Kochab and Pherkad).
  • 4 - If you can see any of the stars in the handle of the Little Dipper.
  • 5 - If you can see 6 of the 7 stars in the Little Dipper.
  • 6 - If you can see all 7 stars in the Little Dipper.
  • 7 - If you can see stars near the Little Dipper that are not part of the stick figure.  (I envy your young eyes...)
Although atmospheric extinction will vary from season to season, and from latitude to latitude, using the Little Dipper is a simple and reasonable solution.


Forrest Erickson
 

David,
Everyone,

My direct email is forresterickson@...

Thanks,
Lee

On 10/17/2022 12:44 PM David Fields <fieldsde@...> wrote:




Suggestions for formatting and otherwise doing so would be of help.


Hi Lee,
Your measure of noting sky transparency is good, provided Ursa Minor is not in a 'special' region of the sky (overly light-polluted or overly dark).  My only suggestion is that you incorporate a note about the Bortle scale, or mention the nice smartphone apps that are available at no charge.  I wrote up all this for this month's Trapezium (ORION newsletter), and will attach the newsletter.. 

My guess is that you'll receive the attachment but that the mail server might not include it.  Anyone wanting to be on the list to receive the Trapezium can signup at groups.io, or send me their email address.

Tonight's ORION meeting is at the Roane State, Oak Ridge Campus at 7 PM -- everyone welcome.

Cheers,
David



-----Original Message-----
From: Forrest Erickson <forresterickson@...>
To: SmokyMountainAstronomicalAssociationGroupsIO SMAS <smokymtnastro@groups.io>
Sent: Sat, Oct 15, 2022 8:28 am
Subject: [smokymtnastro] Adding Seeing and Transparency To Sketches

Attached is the sketching sheet I have been using at star parties in one form or another for some years. One of my most recent changes was to add a note to capture Seeing and Transparency. This caused a problem because I could not remember how the rating system worked once I was under the sky and I could not explain it well to persons sketching sun spots at the Blount County Public Library.

So this morning I went to the Astronomical League web page for the definitions  (here: https://www.astroleague.org/content/seeing-and-transparency-guide) which are below.

I guess I will have to make an eleventh version of the document soon.

Suggestions for formatting and otherwise doing so would be of help.

Lee


Seeing and Transparency Guide

Introduction

Seeing and Transparency are values that an observer uses to compare the quality of the sky from night to night.  The values are very specific to an individual observer's visual acuity.  Seeing is a measure of how stable the sky is.  Transparency is a measure of how clear the sky is. Most of the Astronomical League's Observing Programs require the observer to evaluate these conditions for each observation and to record them in their observation log.


Here are two scales that are acceptable for all Observing Programs.  They are simple to use and require no special equipment.  Both of these values can be done very formally using special equipment, but for the AL Observing Programs this level of effort is not required.

Seeing:  How stable is the sky?​

  • E (excellent) - The brighter stars are not twinkling at all.
  • VG (very good) - The stars are twinkling slightly, but the brighter planets are not twinkling.
  • G (good) - The brighter planets are twinkling slightly.
  • F (fair) - The brighter planets are obviously twinkling.
  • P (poor) - The atmosphere is turbulent.  all objects are twinkling to the points where observation is not practical.
Transparency:  How clear is the sky?​​

Transparency is a measure of what you can see in the nighttime sky in spite of dust, smoke, haze, humidity, or light pollution.  An easy way to measure this is to use the magnitude of the faintest star you can see.  Ideally, this would be looking straight up at zenith.  But, to make life simpler, you can use the Little Dipper (Ursa Minor) if you can see it.  Here is the scale.

  • 1 - If you can't see Polaris.
  • 2 - If you can only see Polaris.
  • 3 - If you can see the two stars on the end of the bowl of the Little Dipper (Kochab and Pherkad).
  • 4 - If you can see any of the stars in the handle of the Little Dipper.
  • 5 - If you can see 6 of the 7 stars in the Little Dipper.
  • 6 - If you can see all 7 stars in the Little Dipper.
  • 7 - If you can see stars near the Little Dipper that are not part of the stick figure.  (I envy your young eyes...)
Although atmospheric extinction will vary from season to season, and from latitude to latitude, using the Little Dipper is a simple and reasonable solution.