Questions tagged [observational-astronomy]

Questions about the techniques and practice of observing the night sky.

Filter by
Sorted by
Tagged with
1 vote
0 answers
6 views

How to show the image of the fits file what I want to see among several fits file in astrodrizzle

Before running astrodrizzle(a library that can align the fits file images), I runned "tweakreg" to update fits header. I used the bullet cluster data, In tweakreg, forty-two "sci1" ...
user avatar
  • 181
1 vote
0 answers
44 views

Need help in writing a query using ADQL (Astronomical Data Query Language)

I am trying to query Gaia archive to get the medium quality sample as mentioned in Reico-Blanco et al. (2022) Gaia Data Release 3: Chemical cartography of the Milky Way. The idea is to query the ...
user avatar
1 vote
0 answers
27 views

In the explanation of fitgeometry=general of drizzlepac.tweakreg.TweakReg, How are there two different rotation with respect to "x axis" and "y axis"?

...
user avatar
  • 181
3 votes
1 answer
178 views

What is the story behind this supposedly incredibly detailed image of the disk of Proxima Centauri attributed to the JWST?

Etienne Klein (@EtienneKlein)'s twitter account labels them as: Directeur de recherche @CEA_Officiel, producteur de « Science en questions » sur @franceculture, publie « L’esprit du corps » and ...
user avatar
  • 32.4k
4 votes
1 answer
104 views

"Holy grail" future observation to confirm presence of neutron stars in the centers of massive, otherwise conventional stars? (Thorne–Żytkow objects)

Wikipedia's Thorne–Żytkow object begins: A Thorne–Żytkow object (TŻO or TZO), also known as a hybrid star, is a conjectured type of star wherein a red giant or red supergiant contains a neutron star ...
user avatar
  • 32.4k
10 votes
1 answer
668 views

What is this object visible in the Chandra image of the Cartwheel galaxy that isn't visible in JWST image?

In the below images I aligned an image from Chandra of the Cartwheel galaxy over the image from JWST. The first is the Chandra image pasted on top, fully opaque. The second is just the JWST image, and ...
user avatar
  • 223
5 votes
1 answer
47 views

Did de Sitter expect to disprove Ritz theory only with visual binaries?

Walter Ritz’s emission theory stated that some fraction of the velocity of an object was added to the speed of light emitted from it. Willem de Sitter pointed out a problem with this in the case of a ...
user avatar
1 vote
0 answers
29 views

How do stellar magnitude and integrated magnitudes compare, perceptually?

(P.S. this is naked eyed) Magnitudes are easily defined for point-like objects i.e. stars. However, for extended objects, the "magnitudes" quoted are actually integrated magnitudes. For ...
user avatar
  • 193
5 votes
0 answers
64 views

Angular resolution of naked eye at night; type of vision used

It appears that most sources quote the angular resolution of the eye as 1', regardless of day and night. For instance, Naked eye Seconds of Arc and the Unaided Eye However, the following websites give ...
user avatar
  • 193
1 vote
2 answers
71 views

Since the Hubble Constant changes over time (it's a variable parameter), why can't the conflicting values of 67.4 and 73 both be right?

Are the conflicting values from the 'early universe' (Planck) method and the 'late universe' (Distance ladder) method actually compatible? Since during the latter period of the universe 'dark energy' ...
user avatar
  • 3,729
6 votes
0 answers
109 views

If I can't unscramble an egg, how do Astronomers unscramble views gravitationally lensed by complex mass distributions?

Quanta Magazine's Two Weeks In, the Webb Space Telescope Is Reshaping Astronomy highlights two submissions to arXiv soon after the first images were released: "Three days later, just minutes ...
user avatar
  • 32.4k
2 votes
2 answers
181 views

Measurement of Planetary Aberration (similar to stellar aberration)

It is often stated that, "Planetary aberration is a combined result of the observer's motion and the time taken for light to travel from a body in the Solar System to the observer". I am not ...
user avatar
  • 101
2 votes
0 answers
126 views

What is the large dim feature near the center of the first James Webb image (of SMACS 0723)?

I was intrigued by the large dim feature (highlighted below) in the center of the first James Webb image of SMACS 0723. Is anything known about it?
user avatar
  • 223
1 vote
1 answer
83 views

What am I looking at when seeing through a 3nm Hα filter?

http://www.astronomyknowhow.com/hydrogen-alpha.htm The line that appears in the red part of the spectrum is created when an electron moves between the second and third orbit (N=2 and N=3) and the ...
user avatar
1 vote
2 answers
38 views

Orientation of the optical telescope assembly in the Hubble Space Telescope

What is the orientation of the optical telescope assembly with respect to the direction of motion of the Hubble Space Telescope? If it happens to be in the direction of motion, does the primary mirror ...
user avatar
  • 101
1 vote
2 answers
98 views

Calculate Earth Zenith Point of Another Planet with Azimuth and Elevation of another Observer Point

I need to find the Longitude of the closest point on Earth (zenith) to Jupiter with the Azimuth and Elevation data from another observation location at a given point in time. Below is the source of my ...
user avatar
13 votes
3 answers
2k views

Identify stars in image from James Webb

This is one of the recent pictures from the James Webb released by NASA. It's a picture of the galaxy cluster SMACS 0723. It locates in the Volans constellation. I'm trying to identify the stars in ...
user avatar
  • 255
21 votes
1 answer
3k views

Why doesn't dark matter clump strongly in the center of galaxies, since it doesn't feel either radiation pressure or the Pauli exclusion effect?

Dark matter is described as being spread not only throughout a galaxy, but also around it in a halo of some sort that extends far beyond the visible parts of the galaxy... In fact, dark matter haloes ...
user avatar
  • 3,729
4 votes
0 answers
55 views

If you could get up close to them, what nebulae would be the most visually impressive to your naked eye?

Pop cult sci-fi movies like to show nebulae as they appear in photographs, but to a live, real-time viewer: these dazzling, snazzy and amazing backdrops to spaceship flying in front of them in real-...
user avatar
3 votes
1 answer
89 views

Why were only 4 days of data used in the M87 EHT observation?

I wonder why only 4 days of data were used in the M87 Event Horizon Telescope (EHT) observation. What is preventing you from obtaining a more detailed and clearer image over a longer period of time?
user avatar
  • 109
1 vote
1 answer
34 views

Why was the NVSS(NRAO VLS Sky Survey) conducted at 1.4 GHz continuum?

I am observing the nature of some galaxies looking at their radio images and contours from NVSS. So, the data collected have radio flux at other wavelengths but I am studying it at 1.4GHz. I have been ...
user avatar
  • 55
-4 votes
2 answers
83 views

What are the Rules of Significant Figures, Precision, and Uncertainty, Strictly Speaking? [closed]

In the physical sciences (which are physics, chemistry, astronomy, materials science, etc.), we learned that the uncertainty is +/- the smallest unit (which is 1) of the last significant figure if the ...
user avatar
2 votes
1 answer
102 views

The constellations in “Powers of Ten”

I watched a video called Powers of Ten made in the 70s. It starts from a view of an area in Chicago and moves the "camera" away from the ground towards the space. At 3m15s of the video, the ...
user avatar
  • 255
1 vote
1 answer
70 views

Time taken calculation to reach synodic degrees between planets

I have a software tool which calculate the synodic period with degree inputs with two planets. Synodic Period is the temporal interval that it takes for an object to reappear at the same point in ...
user avatar
  • 23
0 votes
1 answer
30 views

Recognize the celestial object in UMa

I’m new to Astronomy observations. I took a picture from my phone of a object near beta Ursa Major and m97 which I couldn’t find (I was on low magnification), I couldn’t find out what it was. Any ...
user avatar
1 vote
1 answer
37 views

What can we learn from the rotation data of a star?

Knowing the speed of a star's surface rotation gives us what data and information. For example, if it is a big star, is it possible to measure distance using the doppler effect? Or can we calculate ...
user avatar
  • 109
1 vote
0 answers
17 views

Can this ppxf fit work?

I am trying to do kinematical analysis of spectra using ppxf-algorithm from Capellari. The velocity dispersion I get seems to be to high and I am not sure what the reason could be. On the website of ...
user avatar
  • 359
1 vote
1 answer
91 views

following several unknown phenomena detected at the edge of the solar system, is there a 5th force which acts at the edge of the solar system?

following several unknown phenomena detected as the acceleration of Oumuamua and electrons and strange data sent by traveler 1 at the edge of the solar system, is there a 5th force which acts at the ...
user avatar
0 votes
0 answers
15 views

Kinematical galaxy spectral analysis using ppxf?

I am trying to implement an Fourier based algorithm to derive the kinematics of an elliptical galaxy. To check/reproduce my results I wanted to use the open source ppxf tool (https://pypi.org/project/...
user avatar
  • 359
2 votes
1 answer
36 views

Does humidity affect image formation point while observing through a telescope?

I was wondering if atmospheric humidity affects the point where an image forms through a telescope? I have a 256mm aperture 1200mm focal length Newtonian Reflector. I generally use a 25mm eyepiece and ...
user avatar
1 vote
0 answers
48 views

civil twilight & sunset

Many Internet sources define civil twilight (hereinafter CT) as follows: Any point in time at which the 'geometric center of the sun' is between 0°, inclusively, and 6°, exclusively, below the horizon ...
user avatar
  • 11
4 votes
1 answer
148 views

Does "Angular Diameter Turnaround Point" solve the Great Wall Problem?

According to Wikipedia, The Hercules–Corona Borealis Great Wall is the largest known structure in the observable universe, measuring approximately 10 billion light-years in length. But since it's ...
user avatar
0 votes
1 answer
48 views

Is there any specific way to record observations on any celestial object while looking through a telescope? [closed]

Which aspects or factors do I take into consideration while I record observations on any celestial object?
user avatar
2 votes
1 answer
61 views

Method to get data from NED IPAC and NVSS, without manually giving RA/dec input

I am collecting the radio flux data at 1.4Ghz frequency for all 1544 Markarian Galaxies for a study. For that, I have to first put the names of these Markarian galaxies in NED IPAC and from there ...
user avatar
  • 55
2 votes
1 answer
72 views

How do I phase fold the light curve for a variable star?

I have some observational data for a star where I've done aperture photometry to get a partial period. I understand that you need to use other techniques to estimate a period for stars whose period is ...
user avatar
1 vote
1 answer
63 views

redshift puzzle

I have the central line of the spectrum of an elliptical galaxy (NGC:4697) and a template K-star. I have calculated the redshift z by computing the crosscorrelation function between the galaxy and the ...
user avatar
  • 359
27 votes
1 answer
5k views

Why is the summer solstice night shorter than the winter solstice day?

I was looking at the sunrise and sunset times where I live (Aberdeen, Scotland) and I noticed something odd: the time between sunrise and sunset in winter is longer than the time between sunset and ...
user avatar
  • 373
2 votes
0 answers
47 views

Is there a cosmological model of the evolution of vacuum motion in our universe over time? [closed]

Is there a cosmological model of the evolution of vacuum motion in our universe over time? Does this model starting from a non-vacuum constitute an advantage compared to the cosmological model of ...
user avatar
6 votes
2 answers
75 views

In terms of results, how similar is a bunch of telescopes across the globe to an Earth-sized telescope?

The Event Horizon Telescope emulates an Earth-sized telescope by syncing a bunch of radio telescopes across the planet to do take pictures with a small enough angular resolution to take pictures of a ...
user avatar
  • 1,628
2 votes
0 answers
18 views

LSR and peculiar motion corrections to RAVE survey velocities

I am working towards getting a bunch of halo stars in our galaxy for my thesis. I am doing this with the help of a Toomre diagram and I am stuck. I am using the RAVE survey in conjunction with Gaia as ...
user avatar
2 votes
1 answer
72 views

What exactly causes "color twinkling" and why does it seem that any color might be furthest refracted for a moment?

In this answer to Betelgeuse appears in a rainbow of colors through a Newtonian telescope I link to a video of a bright star imaged at perhaps video rate (I think) through a telescope. In addition to ...
user avatar
  • 32.4k
0 votes
0 answers
39 views

How to plot matplotlib plots as tables in python(hdf5 tables)

I have extracted the data from a fits file and plotted a spectra.i need to do the same for multiple fits files .how can I store the resultant spectra's as a hdf5 table or fits table? And which ...
user avatar
  • 1
6 votes
2 answers
367 views

How could I see Andromeda as large as in this picture?

In this question an image is shown (repeated below) which gives an idea of the "true" angular extent of the Andromeda galaxy in our sky. When I see Andromeda it is usually a bit of a smudge ...
user avatar
  • 117k
12 votes
1 answer
1k views

Is the scaling in this composite photo of the moon and the Andromeda galaxy reasonably correct?

I came across this image which purports to show what the size of the Andromeda galaxy would be in the night sky if we could see its dim stars with the naked eye. Is this image reasonably correct with ...
user avatar
  • 585
3 votes
0 answers
54 views

How are plage regions related to the density of medium and velocity FeII ions?

During a literature review (abstract), I found that the intensity of FeII (298.5 nm) ions in the last solar minimum was higher than the two previous solar minima 21 & 22. The velocity of FeII ions ...
user avatar
0 votes
1 answer
66 views

Calculate how many days left for synodic period from particular planet

One of the many tools used in Astronomy are the formulas used to determine Orbital Motion. There are two basic forms of orbits: Sidereal Period Synodic Period For Jupiter: $$\mathrm{\frac{1}{P} = \...
user avatar
  • 23
2 votes
1 answer
38 views

How to fit LOSVD of a galaxy with gauss hermite parametrization

I have recovered the following LOSVD from an elliptical galaxy, that I now want to fit a gauss-hermite-parametrization to and derive the kinematical parameters rotational velocity, velocity dispersion ...
user avatar
  • 359
0 votes
0 answers
63 views

Two objects that looked like stars? [duplicate]

My husband and I were on the back porch looking at the stars, and two caught my eye when I noticed they were moving away from us in a zigzag pattern we watched until we couldn’t see them anymore. The ...
user avatar
2 votes
0 answers
76 views

History, significance and "drama" (if any) of T-Tauri stars, especially the early bits?

In this answer to Can I write a systematic review as an undergraduate and get it published in a journal? in Academia SE I recounted my memory of an experience from circa 1980: I had an initially ...
user avatar
  • 32.4k
0 votes
1 answer
152 views

What else can we learn from a Foucault pendulum? Have they ever been used to determine anything more than that the Earth rotates on its axis?

Background Each semester we have to make up projects for each course. This semester I took Cosmology and Astrophysics and we covered a vast amount of topics, from luminosity of stars to Einstein's ...
user avatar

1
2 3 4 5
23