Questions tagged [right-ascension]
Questions regarding the second ordinate of the equatorial celestial system.
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Hour angle to Right Ascension correct when the longitude is positive
I'm developing a Astronomical software using the formulas from the book: "Practical astronomy with your Calculator and Spreadsheet", but I'm having some problems to get the right ascension ...
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calculate declination and right ascension with limited information
I'm trying to make a game with high accuracy moon position so I followed some equations on geoastro.de Basics of Positional Astronomy and Ephemerides and with some help from the questions answers, I ...
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Position of Hamal (alpha Arietis) between 1582 and 1588
Between 1582 and 1588, Tycho Brahe observed $\alpha$ Arietis from Uraniborg (55°54′28″N 12°41′48″E) on at least 27 separate occasions and made a record of the right ascension of the star (see Opera ...
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Sidereal time of rising and setting of the sun on the arctic circle
$$
cos(h)= -tan(\delta)tan(\phi)
$$
$$
\Theta = h + \alpha
$$
if these two equations are the correct equations to solve the following question why doesnt it yield the same answer for the sideral ...
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How to even approach this type of question
Can someone tell me how one would approach this type of question. is there an equation we would use or something of the sort.
Ths solution to this question is given below but I just want to understand ...
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Plotting galactic latitude in Ra vs Dec plane
I have an open cluster with calculated percentage of polarization and position angle. I want to have it's scatter plot in Ra vs Dec plane and superimpose a galactic parallel on it. How to plot the ...
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Does RA/Dec vary with the Earth's orbit around the Sun?
I think the RA and Dec of a celestial object should change (ever so slightly) with the Earth's position in its orbit. So do we ignore this in general?
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How to convert GMST to GMST° (degrees) for calculating RA [duplicate]
For calculating the Right Ascension of the moon I need the GMST (Greenwich Mean Sidereal Time) in Degrees.
I have found the formula
GMST = 100.4606184 + 0.9856473662862 * D + H * 15,
D = number of ...
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Convert RA from hours to h:m:s
I'm working on a small mount controller software in Python. From the ASCOM standard, right ascension is reported in unit of hours.
How do I convert from hours to hours:min:sec?
Here is my attempt in ...
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How to calculate Local Sidereal Time from RA of a star and Longitude of Observer
I have been banging my head against a wall trying to understand these time conversions and the relation between all of these astronomical measurements.
This is the question I am currently working on, ...
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How to get the right ascension of the Moon?
Is there any approximate way to calculate the right ascension of the Moon? I already got declination but still, need the right ascension to calculate the final position of the moon. Thanks for all ...
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Right ascension and declination visible at that local time and location
If I know the local time of an observer and her/his latitude and longitude, how can I know which stars are visible?
I'm developing a planetarium software using the Hipparcos Catalogue. I have also ...
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Figuring out camera pitch and roll given RA and DEC of center of image, as well as lat,long of camera and time taken
What I am trying to figure out is how to get the camera pitch and roll, as described in this image (the green yaw line is where the camera sensor is pointing
if given a RA, DEC (of center of image,ie ...
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Azimuth and Altitude angle between two points in the sky
I want to know how to correctly calculate altitude and azimuth difference, separately, between two points in the sky. The same way will be with icrs coordinates.
For the altitude difference, I simply ...
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How to calculate the local time of sunrise and azimuth of rising point of Sirius?
I know that right ascension equals to $6^h45^m$ and declination equals to $-16°43'$. I need to calculate local time of sunrise and azimuth of rising point of Sirius on 23 of September for an ...
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What's the Right Ascension & Declination of Galactic Left & Galactic Right?
For the purpose of being able to align my model to the galactic plane, I want to know the directions of the galactic center, anti-center, north, south, left & right.
This gives me the answer for ...
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At what rate does the right ascension and declination of a planet, the sun and moon change per hour?
I'm currently building a web app and am getting the RA's and Dec's of solar system objects based on date and time chosen by the user. Then using the gmst for 0 hours of the date, the app calculates ...
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At what time of the day of autumnal equinox the Sun's equatorial coordinates reach max value?
I'm trying to solve this task:
At what point in time of autumnal equinox day, at sunrise or sunset will
a) the declination of the Sun
b) the right ascension of the Sun
reach the maximum value?
I'm ...
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Is the Ra/Dec of Alnitak in Orion's Belt known to be correct?
I've obtained right ascension / declination information about some of stars in the Orion constellation from a few different sources and imported this into an open source video game I'm making. Using (...
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Sun right ascension and declination at date with different values on different calculators and also with my implementation
I'm reading the book "Practical Astronomy with your Calculator or Spreadsheet 4th Edition" implementing its formulas with C++.
Now, I have implemented formula 47 "Calculating orbits ...
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What is the rate of change by day for a given right ascension?
I am writing a small Julia app to get my feet wet in that language. And I want to calculate "what's up tonight" based on a table of right ascension (RA)/Dec(lination) (table of stars), a ...
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Is this how stars’ right ascensions correlate to planets’ longitudes on a 2d map?
This is my first ever online question, so please bear with me:
I’m working on an A1-sized map of at least 100 of the largest solar system bodies (henceforth just called ‘planets’, ignorning the IAU ...
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What's the difference between minutes and arcminutes?
I read in trigonometry class that 1 minute is equal to 1/60 degrees. So, 'minute' is an angular unit. But also 'arcminutes' are used to measure seperation between celestial objects and also equals to ...
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RA and Dec of Near-Earth-Objects
I'm new to the forum.
This might be a silly question. I had a confusion about how RA and Dec are calculated. So, from what I understand RA is the angle made by the position vector of an object(...
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How can you find the distance to a galaxy using right ascension and declination?
For example, Galaxy NGC 3689 has the right ascension of 11:28:11 and declination of +25:39:40.0. Using these values, how can we find the distance to the galaxy? If it helps, its radial velocity is ...
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Right Ascension of North Celestial Pole
My scope simulator is pointing to the celestial north pole.
My position is 41º 27' lat and 2º 15' long.
At 12h 43m local time (11h 43m UTC) the coordinates read from the scope are:
RA: 16h 14m 25s
DE: ...
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How to convert Proper Motion in RA & Dec to Galactic Coordinates
I'm trying to parse stellar data in the GAIA 2 release to galactic coordinates and am struggling with the velocity component. I've tried following online documentation and papers, but end up with ...
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Calculating the time a star is at my local meridian based on its right ascension
I've been watching an astronomy course on YouTube and I'm struggling to calculate stars' positions based on their right ascension.
What I'm trying to achieve: Calculate when a star (Sirius in this ...
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What is the area of the Summer Triangle?
I'm pretty sure spherical trigonometry comes into use here but I don't know how to calculate the area. I'm pretty sure Vega, Deneb, and Altair's declination and right ascension figures need to be ...
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How can I calculate the right ascension of an observer on Earth's surface in the TEME frame with python.skyfield?
I would like to calculate the right ascension of a point on earth as specified above with the Skyfield Python library, and I can not figure out how to do this.
I know that calculating the geocentric ...
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