Circumpolar star declination problem

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Homework Help Overview

The discussion revolves around determining the minimum declination for a star to be considered marginally circumpolar for an observer located on Damavand Mountain in Iran. The problem involves understanding the relationship between the observer's latitude, altitude, and the declination of stars.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the conditions for a star to be circumpolar, questioning whether altitude affects these conditions. There is an exploration of how to mathematically express the relationship between latitude and declination, as well as the implications of being at a higher altitude.

Discussion Status

The discussion is ongoing, with participants sharing insights and seeking clarification on the mathematical procedures involved. Some guidance has been offered regarding the importance of altitude and its effect on visibility, but no consensus has been reached on a specific approach to the problem.

Contextual Notes

There is a focus on the observer's altitude and its impact on the visibility of stars, as well as the need for a clear understanding of the geometric relationships involved in determining star declination.

trina1990
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The Damavand Mountain is located at the North part of Iran, in south coast of
Caspian Sea. Consider an observer standing on the Damavand mountaintop (latitude =
35° 57′ N; longitude = 52° 6' E; altitude 5.6 x10^3m
from the mean sea level) and looking at
the sky over the Caspian Sea. What is the minimum declination for a star, to be seen
marginally circumpolar for this observer. Geodetic radius of the Earth at this latitude
is 6370.8 ݇݉km. Surface level of the Caspian Sea is approximately equal to the mean sea level


i know the condition of a star being circumpolar is that it's latitude should be greater than declination? is it only applicable to altitude=0m or with all altitudes?

please give me some initial guidelines to solve it out...
 
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hi trina1990! :smile:
trina1990 said:
What is the minimum declination for a star, to be seen
marginally circumpolar for this observer.

doesn't it just mean what is the declination of a star sitting due north on the water?
 
thanks for answering...
of course it's that, but my question is how can i explain this procedure mathematically?...

i just wanted to know the process of measering star declination &then asked if the circumpolar condition changes if i change the altitude?

for circumpolar stars i only know their latitude should be greater than declination...how can i use this info to walk through this problem?
 
hi trina1990! :smile:
trina1990 said:
for circumpolar stars i only know their latitude should be greater than declination …

no, because you're on a mountain top, so you can see stars that are lower than usual :wink:
 
well, so there altitude matters...i can see the stars below horizon due to my high altitude & refraction on the atmospheric layers...

but can you please suggest me the clue to derive this declination?
 
all you need to know is the angle below horizontal from the mountain to the horizon …

so draw a diagram! :wink:​
 

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