Deriving RA/Dec from a known sky to an unknown sky

In summary, by using the known RA/Dec and coordinates of stars in the first image, along with a transformation from azimuth/altitude to RA/Dec, you can accurately determine the RA/Dec of an unknown object in a second image.
  • #1
solarblast
152
2
I hope I can make sense out of this question. Suppose I have an image of the sky and know on that image say the RA/Dec and x,y position of 20 stars, and the time the image was taken. The zenith is somewhere in the middle. Now suppose one hour later I have another image of the sky, and would like to determine the RA/Dec of an unknown object. (x,y) would be known. I would think that I could find the az/al for the 20 stars in the first image, and apply them to the unknown object. Next apply a transform from az/el to RA/Dec in the second image--noting the time change. Would that work?
 
Astronomy news on Phys.org
  • #2
Yes, this should work. You can use the known RA/Dec of the stars in the first image, along with their x,y coordinates, to determine the azimuth and altitude of each star. Then you can use the same transformation from azimuth/altitude to RA/Dec for the second image, with the time change taken into account, to determine the RA/Dec of the unknown object in the second image.
 

1. How do you calculate the right ascension and declination coordinates for an unknown sky?

The right ascension (RA) and declination (Dec) coordinates for an unknown sky can be calculated using trigonometric equations and the known coordinates of reference stars. These equations take into account the Earth's rotation and the observer's location on Earth.

2. What is the significance of right ascension and declination in astronomy?

Right ascension and declination are the two coordinates used to locate objects in the sky. Right ascension is similar to longitude on Earth, while declination is similar to latitude. Together, these coordinates allow astronomers to precisely pinpoint the location of celestial objects.

3. Can right ascension and declination coordinates change over time?

Yes, the right ascension and declination coordinates of celestial objects can change over time due to the Earth's rotation and the objects' own motion through space. This is why precise measurements and calculations are necessary when determining these coordinates.

4. How can RA and Dec be converted to other coordinate systems?

Right ascension and declination can be converted to other coordinate systems, such as equatorial or ecliptic coordinates, using conversion formulas. These conversions may be necessary for different types of observations or for comparing data from different sources.

5. Are there any tools or software available to help with deriving RA/Dec from a known sky to an unknown sky?

Yes, there are various software and online tools available that can assist with calculating and converting right ascension and declination coordinates. These include astronomy software packages, online coordinate converters, and databases of reference stars and their coordinates.

Similar threads

I A busy and interesting night sky in Mackinaw City
    • Astronomy and Astrophysics
Replies
1
Views
892
Fisheye Lens (alt/az) to Flat (RA/Dec)?
    • Astronomy and Astrophysics
Replies
1
Views
3K
Stargazing Fixing declination runaway on a Meade LX200 telescope
    • Astronomy and Astrophysics
Replies
6
Views
2K
How Do You Calculate Angular Separation of Stars Using Different Coordinates?
    • Astronomy and Astrophysics
Replies
4
Views
16K
B Vulpecula, pulsars and neutron stars
    • Astronomy and Astrophysics
Replies
10
Views
1K
Predicting the Location of a Star Within an Image
    • Astronomy and Astrophysics
Replies
1
Views
3K
I Phase Contrast Telescope - Part II
    • Astronomy and Astrophysics
Replies
25
Views
1K
Calculating RA and Dec from long/lat/time/alt/azm
    • Astronomy and Astrophysics
Replies
1
Views
4K
What is the mysterious purple-violet oval in the night sky?
    • Astronomy and Astrophysics
Replies
10
Views
3K
Mysterious Night Sky Object - Help?
    • Astronomy and Astrophysics
Replies
15
Views
4K

Hot Threads

Recent Insights

Back
Top