The methods and techniques for gathering astronomical data, as well as the limitations thereof.

learn more… | top users | synonyms

3
votes
1answer
113 views

When one can make telescope that can distuingish 1 mas?

When one can make telescope that can distuingish(angular resolution) 1 mas object by angular diameter? If already possible, tell the name of telescope/observatory. How to calculate angular resolution ...
6
votes
1answer
100 views

Are there rogue planets between Sun and Proxima Centauri?

Would we be able to detect (via emitted radiation, or its gravity) a rogue planet between us and Proxima Centauri? How big would that planet need to be?
4
votes
2answers
274 views

Do green stars exists?

I asked a university lecturer why we don't observe green stars, and he said the blackbody curve averages at that frequency such that the cones in our eyes don't recognise it. I have a hunch that ...
5
votes
2answers
684 views

Planck satellite 2013 results impact on cosmological models

I've recently watched a "Through the Wormhole" episode from 2010 named "What Happened Before the Beginning?", where cyclic and ekpyrotic cosmological models are explained. In this episode the creators ...
6
votes
1answer
97 views

How far can one look into space while relying on light in the visual spectrum?

Put the other way around. From how far does visible light reach the Earth to be observable by a telescope that operates in this spectrum? Gas clouds for instance absorb light. A star behind such a ...
3
votes
1answer
57 views

What is the minimum time period for constellations to change shape?

All stars are revolving around the center of galaxy. And so I wonder how long it takes before we can see any noticeable change in the shape of any constellation? What are the factors one will use to ...
1
vote
1answer
90 views

Rate of twinkling of stars

According to "Why do stars flicker?", the twinkling of stars (stellar scintillation) is caused by the thick layers of turbulent air in the Earth's atmosphere. While the explanation is convincing, it ...
5
votes
1answer
147 views

Why is there a line in the middle of the Planck full sky map?

Why there is a straight line (or perhaps a flat surface) in the middle of the Planck full sky map? and zoom (it makes it seem that the big bang was a collision between two unknown surfaces)
6
votes
1answer
360 views

How big of a telescope to view Gliese 581g in great detail?

I've always been interested in mega sized telescopes and how big they would have to be to see exoplanets in great detail. So, Gliese 581g is 22 light years away. Could we build a telescope in space ...
8
votes
3answers
625 views

Why do stars flicker?

Why do stars flicker and planets don't? At least this is what I've read online and seen on the night sky. I've heard that it has to do something with the fact that stars emit light and planets reflect ...
4
votes
3answers
359 views

Is it possible to take a picture of a star?

In this question I am not considering the sun, but only other stars. Stars are big, but they are also far away. https://en.wikipedia.org/wiki/Star The nearest star to the Earth, apart from the ...
1
vote
0answers
164 views

How do I obtain the Point Spread Function (PSF) of a ground telescope?

I have some galaxy kinematic maps (velocity maps) extracted from Integral Field Spectroscopy (IFS) datacubes. Like any observation data coming from a ground telescope, these velocity maps include (ie: ...
1
vote
1answer
49 views

Dimensions of a variable celestial body?

I read (extern link to a filehoster, page 163 section 4.8) that a variable celestial object like a pulsar or quasar must be smaller than the distance the light travels in its variation period. Can ...
8
votes
1answer
297 views

How can one get the eccentricity of the orbit of the Sun around center of the Milky Way?

How can one get the eccentricity of the orbit of the Sun around center of the Milky Way? Can it be measured?
6
votes
3answers
132 views

How is the distance to a $\gamma \mathrm{-ray}$ burst (GRB) measured in just a few days?

Recently the Fermi Gamma-ray Space Telescope recorded the most energetic Gamma Ray burst (GRB 130427A) yet observed with a peak $\gamma \mathrm{-ray}$ energy of $94\, \mathrm{GeV}$. Various sources ...
0
votes
2answers
229 views

How can we detect a black hole? [duplicate]

If black holes are phenomena of very high density (gravitational singularities) which don't emit radiation how can we detect them so far away from us where so much other radiation can hide the black ...
0
votes
2answers
417 views

I want the Saturn's position in terms of Declination and Right Ascension?

I want the Saturn's position in terms of Declination and Right Ascension for a couple of month in the interval of 1 hour in a text file to do a simulation. Which site can provide me these data? Or, ...
1
vote
2answers
163 views

Is there anyone calculate the probability of extrasolar planets?

After reading an recent news "Stargazers capture first picture of a planet with two suns – just like Luke Skywalker’s home planet of Tatooine in Star Wars", I am thinking that: can we calculate the ...
2
votes
2answers
122 views

Spot of my light on the moon

This is a funny question, but worth answering. The distance between the moon and the Earth is 384,400 km. The speed of light is 299792.458 km/s. It will take 1.3 seconds (Approx.) for my laser beam to ...
3
votes
2answers
300 views

Why is the dark matter density profile within the solar radius (and local density) uncertain?

It seems that we know the rotation curve inside the sun's galactic orbit fairly accurately. Then wouldn't we be able to just take the derivative* of this to get the DM density profile at smaller ...
1
vote
1answer
75 views

How “big” objects can WISE and NEOWISE detect?

I mean WISE is monitoring near-Earth objects, but cannot see the latest Russian meteor and others. Why can it not detect small objects? What is the limit of it's infrared detectors?
1
vote
1answer
135 views

How can we determine during a lunar eclipse whether the earth moves faster or the moon

How can we determine during a lunar eclipse whether the earth moves faster or the moon using minimum instruments?
8
votes
3answers
610 views

What made us think that Earth moves around the Sun?

Trying to observe the night sky for a few weeks, the motion of the Sun and the stars pretty much fits into the Geocentric Theory i.e. All of them move around the Earth. What then, which particular ...
4
votes
3answers
567 views

How far are constellations recognizable?

A novel of the 'Foundation' series mentioned that the universe being 3-D the shape of a constellation is recognizable only in the near vicinity of a given planet. In other words move out from the ...
6
votes
1answer
193 views

Why is the Hubble Space telescope able to see farthest in the universe?

What determines how far a telescope can see in the universe? How does recording data for a very long time (~10 years) help? If we could build a telescope which work at microwave region, will it be a ...
7
votes
4answers
3k views

View of the Sun from Voyager 1

Today Voyager 1 is approximately 122 AU distance from the Sun. What does the sun look like from this distance? How much brighter does the sun appear to the naked eye compared to other stars in the ...
3
votes
1answer
108 views

If the observable universe keeps expanding would we eventualy see light 24/7… clouds permiting? [duplicate]

If we can see more observable universe could there be a time when day and night looked the same?
5
votes
1answer
312 views

What is the status of existing measurements of the speed of gravity?

In replying to a recent question I stated: Gravitational waves have not been yet experimentally observed so as to have their velocity measured. Which after the fact prompted me to try and verify ...
7
votes
1answer
527 views

How does nuclear war look like from space?

As today's the 29th anniversary of possible Armageddon, had Mutual Assured Destruction taken place, with the USA and USSR exchanging most of their nuclear arsenal, what would someone In low earth ...
3
votes
1answer
234 views

Error analysis of flux from telescope-CCD setup (photometric calibration)

I am doing photometric calibration of a telescope and am trying to work out the errors on the flux that I measure. I have attempted to work out the errors due to the process of removing bias, dark ...
4
votes
2answers
877 views

At what distance could you see andromeda with the naked eye?

We've all seen the telescope photographs of andromeda galaxy: I'm wondering if it were possible to travel close enough to the andromeda galaxy could you achieve a same perspective with the naked ...
4
votes
1answer
45 views

Missing radio source coordinates in G/T measurement technique ITU-R S.733.2

Section 3 ‘Suitable radio stars’ of this recommendation lists the different stars/nebula and their corresponding flux-densities that can be used in the G/T measurement. There is no reference to the ...
8
votes
2answers
868 views

Is it possible that I just saw Jupiter's moons?

Today at about 18:00 I was looking for Venus near the moon and I saw a short bright line. I thought that maybe I was seeing Venus' crescent but it was perpendicular to the crescent of the moon. I then ...
1
vote
1answer
60 views

Confusing description of Orions belt, could someone clarify?

The Wikipedia article about Orion's belt contains this confusing sentence: They also mark the northern night sky when the sun is at its lowest point, and were a clear marker for ancient ...
1
vote
2answers
375 views

Light pollution calculation using camera

Is it possible to calculate light pollution values using camera (analyzing camera feed) integrated in new smartphones (8 Mpx camera) but with pretty decent accuracy? Or that is only possible with ...
5
votes
1answer
63 views

Best observing techniques for a Total Lunar Eclipse?

Is there any good tricks to observing a total lunar eclipse that I should be aware of? Just wanting to know what to do to be prepared for the upcoming one, but please post in general for future ...
4
votes
2answers
508 views

How is the Hanbury-Brown and Twiss effect used to measure the size of stars?

I understand what an Hanbury Brown and Twiss (HBT) interferometer does, but how can this be used to measure the apparent angular diameter of some object? What is the mathematical explaination?
3
votes
2answers
208 views

The Bahtinov focusing mask

I'm looking for a webpage or a book or reference that might give me a better (and hopefully more scientific) understanding of how the Bahtinov mask works (which I understand to be the same as ...
6
votes
1answer
51 views

Transit of Mercury: how did he see it?

On November 7, 1631 Pierre Gassendi saw the transit of Mercury across the face of the Sun. How did he see it? I mean what instrument was used to reduce the apparent brightness of the Sun?
3
votes
2answers
65 views

Particular targets of high angular resolution infrared telescopes

I work in the field of infrared interferometry, specifically instrumentation. As such, I need to be aware of the science goals of such an instrument. Is there a quick list of important and ...
6
votes
2answers
1k views

What are the differences in using an eyepiece with a barlow instead of a shorter eyepiece?

I intend to start making visual observations, and I want to know more about the difference between using barlow lenses and one or two eyepieces and using a complete kit of eyepieces, both for ...
3
votes
1answer
84 views

What is the format for “local catalog” files used by JSkyCat?

I am trying to use JSkyCat to mark a set of coordinates on a FITS image, and have found the dialog for choosing a catalog file to load. However, I am having trouble finding any documentation on what ...
6
votes
2answers
251 views

If you focus in on one image, is combining two telescopes really equivalent to a larger mirror?

Have a look at this example: In addition, the Keck I and Keck II telescopes can work together as the Keck Interferometer. The 85-metre (279 ft) separation between the two telescopes gives them the ...
2
votes
3answers
158 views

Did I see two Milky Ways next to each other?

I am from the northern hemisphere and as far as I remember, the Milky Way was "single lane", just one stripe. At least, this is what I recall the Milky Way to look like when seeing it from near ...
4
votes
3answers
103 views

How long would it take to scan the visible universe for unique signals?

The article Amazing rays as star succumbs to dark side talks about a very large black hole swallowing up a star. The report goes on to say that the only reason it was discovered was because it shot ...
9
votes
1answer
45 views

How do I use this 'Horizon Observatory'?

Just around the corner, we have one of these: It's at the Halde Hoheward (article in the German wikipedia), and it's called a 'Horizon Observatory' by the people who built it. How does it work ...
4
votes
6answers
163 views

What possible science could we do during the 2012 Venus transit? [closed]

I had previously asked about how useful everyday solar physics data is to other astronomers ... But about a year from now, we will have another Venus transit, where Venus will pass between the sun and ...
4
votes
1answer
30 views

Are solar physics images of use to the night-time community?

I'm actually interested in cases of cross-discipline data re-use. I know that the SOHO/LASCO coronographs are used for comet finding, that solar telescopes were used to get information about Venus's ...
10
votes
2answers
2k views

Observing Jupiter's non-Galilean moons

What strength of telescope is required to observe some of the non-Galilean moons of Jupiter? My current telescope at 50 magnification resolves the Galilean moons well, but I'm guessing it's far ...
7
votes
6answers
1k views

Can any telescope be used for solar observing?

Can any telescope, such as a 8" reflector, that is normally used at night to look at planets be used or adapted for solar observing? What kind of adapters or filters are required or is it better to ...