# Tagged Questions

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3answers
3k views

### Could someone explain RA/dec in simple terms?

The equatorial coordinate system isn't too complicated. However, for people new to this, it seems rather intimidating at first. Is there an easy way to explain it?
1answer
5k views

### Calculation of right ascension and declination

I am confused about this problem: If I see an object from Mount Teide (longitude is 16"30'E and latitude is 28"18'N) that passes the meridian (azimuth=0) at 5h (am) UTC, and I also know that the ...
1answer
52 views

### Low precision GMST formula clarification

According to the website http://aa.usno.navy.mil/faq/docs/GAST.php, a low-precision way of calculating the GMST is via the following formula: GMST = 18.697374558 + 24.06570982441908 D The website ...
1answer
54 views

### iteration to cover the whole sky with right ascension, declination, angle

I am sure I get parts of the terminology wrong but if anyone can shed some light in the following: I understand that for a given right ascension (RA) and declination (DEC), one has defined a ray (...
2answers
65 views

### How do I find the RA of sunset and sunrise in a specific location?

I want to make some observations with a telescope in Hawaii on Mauna Kea but I am living somewhere else (not Hawaii) and I want to plan a night's viewing on the Hawaiian telescope. How do I find the ...
1answer
47 views

### How to find maximum and minimum right acsension and declination based on the telescope's location?

If I am to apply at a telescope for viewing objects, how to determine (easily) what is the minimum and maximum possible RA and DEC visible from that telescope during that time of the year. For eg, ...
0answers
62 views

### Determining planetary positions on the celestial sphere by Right Ascension and Declination

How would one go about determining the position of the different planets in our solar system with respect to the celestial sphere based on the following data set? Is there a practical way to calculate ...
2answers
74 views

### Does the retrograde movement affect the true angular distance between 2 planets?

I need to calculate the relative angular path between two planets in the geocentric view or in other words the number of degrees of a circle one planet travels away from another planet around the ...
1answer
23 views

### Calculate right ascension in Zenith at this moment in my location

I've been searching on Internet about how to calculate which RA is in zenith at a given location in a given time but I haven't find anything (or maybe I don't know how to search). Using my star ...
1answer
38 views

### Calculating Right Ascension and Declination from Latitude / Longitude / Time

I have a latitude / longitude / time of a location on Earth, I need to calculate the Right Ascension / Declination that's overhead at the time provided. So far I've found out that Right Ascension is ...
1answer
102 views

### Declination and Ascension - the Sun and Andromeda

If Andromeda is overhead at midnight, what is the right ascension of the sun? (andromeda is ar RA =1hr, Dec = +40). I thought I understood what Dec and RA were, but I can't think of how to start this ...