Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User
WRAK
sage
Reged: 02/18/12
|
Relationship LP and Telescope magnitude limit
#5538310 - 11/25/12 06:17 AM
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
There are established algorithms for calculating the theoretical magnitude limit of a telescope depending on aperture. Do you know of a similar proven formula for light polluted skies based not only on aperture but also on the naked eye magnitude limit?
Wilfried
|
csa/montana
Den Mama
Reged: 05/14/05
Loc: montana
|
Re: Relationship LP and Telescope magnitude limit
[Re: WRAK]
#5540008 - 11/26/12 09:57 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Here's one that might be of interest:
Naked eye limiting magnitude
|
WRAK
sage
Reged: 02/18/12
|
Re: Relationship LP and Telescope magnitude limit
[Re: csa/montana]
#5541508 - 11/27/12 04:20 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Thanks, certainly of interest - but what I am looking for exactly would be an extension to the formula for calculating the Telescope Limiting Magnitude like for example "TLM=2,7+5*LOG10(D_mm)-f(NELM)".
Wilfried
|
derangedhermit
sage
Reged: 10/07/09
Loc: D/FW, TX
|
Re: Relationship LP and Telescope magnitude limit
[Re: WRAK]
#5542455 - 11/27/12 04:41 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
NELM is not a useful measurement of light pollution for use in such a formula. It is too dependent on the observer.
|
Tony Flanders
Postmaster
Reged: 05/18/06
Loc: Cambridge, MA, USA
|
Re: Relationship LP and Telescope magnitude limit
[Re: WRAK]
#5542827 - 11/27/12 09:10 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Quote:
Thanks, certainly of interest - but what I am looking for exactly would be an extension to the formula for calculating the Telescope Limiting Magnitude like for example "TLM=2,7+5*LOG10(D_mm)-f(NELM)".
Wilfried
I'd say that a fair approximation for binoculars is:
BLM = NELM + 2.5*LOG10(mm/7 * mag)
However, this isn't really linear with magnification; it's faster than linear for low magnifications, and magnification becomes almost irrelevant at exit pupils smaller than 1 mm.
Binocular vision is worth about 1/4 magnitude. So subtract 1/4 mag for monocular telescopes.
|
WRAK
sage
Reged: 02/18/12
|
Re: Relationship LP and Telescope magnitude limit
[Re: Tony Flanders]
#5543691 - 11/28/12 11:39 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Tony, thanks - I have checked this and found good values with strong light pollution with NELM around 3 but not these good with less light pollution giving values above the standard TLM formula. But this should be resolvable with some adaptions.
Wilfried
|
GeneT
Ely Kid
Reged: 11/07/08
Loc: South Texas
|
Re: Relationship LP and Telescope magnitude limit
[Re: csa/montana]
#5552959 - 12/03/12 10:08 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Quote:
Here's one that might be of interest:
Naked eye limiting magnitude
Nice chart!
|
|
0 registered and 3 anonymous users are browsing this forum.
Moderator: LivingNDixie, richard7
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 900
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
