The science dealing with objects and phenomena located beyond Earth. In particular, this applies to observations and data. At its core, astronomy is the physically informed cataloging and classifying of the contents of the universe in order to better understand what is out there.

learn more… | top users | synonyms (2)

6
votes
1answer
4k views

How do we know the masses of single stars?

I have recently read that we can only know the masses of stars in binary systems, because we use Kepler's third law to indirectly measure the mass. However, it is not hard to find measurements for the ...
9
votes
1answer
19 views

Ring height stats?

I'm working on a basic simulation system which will include planets with rings, I want to create dust and asteroids within a 3D ring but I'm struggling to find any stats on the sort of height ranges a ...
6
votes
2answers
214 views

Io - Turned inside out

In a lot of the descriptions of the moon Io it frequently states that the moon, because of volcanic activity, has been literally "Turned inside out". What exactly is meant by "Turned inside out" and ...
15
votes
1answer
236 views

Impact location that created the moon

I was reading an article today about the 1000th orbit of the Lunar Reconnaissance Orbiter, and as many of you know NASA created an animation that simulates the history of the moon. It is speculated ...
4
votes
2answers
1k 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 ...
3
votes
2answers
123 views

Figuring out which moons of Jupiter I saw through my telescope

Three days ago (Sunday 11st March) in London using my new telescope I was able to see Jupiter and three of its moons. It was very clear and easy to spot. How can I determine the names of the moons I ...
2
votes
1answer
168 views

May 20th Annular Eclipse - Duration from Vancouver?

On May 20th, there's an annular eclipse. It's technically visible towards the end from Vancouver. In the middle, the duration is just under 6 minutes. What I want to know is what the duration is ...
11
votes
3answers
2k views

Can you damage your eyes viewing Venus?

Whilst I know it is extremely dangerous to view the sun using a telescope (or even just looking directly at it for prolong periods) can you do permanent damage to your eyes looking at Venus through a ...
3
votes
1answer
1k views

How to draw a star chart?

How does one draw a star chart like this? I have: a star database with coordinates (right ascension - RA, declination - DEC), observer coordinates (latitude, longitude) and time of observation. I ...
11
votes
3answers
2k views

Is it possible to see satellites with the naked eye?

Every now and then I notice some very bright "stars" in the sky. They tend to be very few (one or two, usually), and are quite much brighter than any other star out there. Often they're perfectly ...
5
votes
1answer
25 views

Is there any site/place which gives access to astronomical signals acquired from space?

I am an engineer and I'd like to know if there are any places which provide access to any kind of astronomical signals acquired from space using radio telescopes.
2
votes
1answer
42 views

Existing photometry data of the open star cluster Cepheus OB3?

I am doing research with my teacher on photometry of the open star cluster Cepheus OB3, and we are trying to find research papers so we can target stars in the photos we took. Are there any existing ...
6
votes
2answers
2k views

How can I determine if my telescope mirror is parabolic?

This week I purchased the “Skywatcher Explorer 130P Newtonian Reflector Telescope”, specifically as it has the parabolic mirror. I do not have the outer packaging for sundry reasons. Therefore, after ...
4
votes
1answer
1k views

Convert ECI coordinates to latitude/longitude?

I have been given output in (what I believe to be) ECI format (from OrbitTools): ...
6
votes
2answers
259 views

What's the best way to start out with astrophotography on a tight budget?

I'm new to astronomy and I don't have a great deal of cash to spend. I currently have a 3" reflector telescope which I've had great fun with. I also have a Pentax DSLR which I've been using to take ...
5
votes
5answers
2k views

Is there such a thing as “North” in outerspace?

On Earth, North is determined by the magnetic poles of our planet. Is there such a thing as "North" in outerspace? To put it another way, is there any other way for astronauts to navigate besides ...
6
votes
1answer
116 views

Why does Omega Centauri have a distinct chemical signature from the rest of the Milky Way?

In answering a question about the orbital path of Omega Centauri, I learned that it has a distinct chemical signature from the rest of the Milky Way. Basically, it is very rich in s-process elements, ...
6
votes
1answer
158 views

Frequency of nomad planets passing within 30 AU of the sun

A recent estimate by the Kavli Institute for Particle Astrophysics and Cosmology (a joint institute of Stanford and SLAC) is that there are circa 100000 times as many 'nomad planets' as stars I ...
3
votes
1answer
498 views

Sky-Watcher Skymax-127 (AZ) 127mm (5") f/1500 SynScan GO-TO Maksutov-Cassegrain Telescope

I have not purchased the above item yet but was wondering whether or not I should? Can I hook this scope up to a monitor or laptop so I can see what my scope is seeing? Is this scope is any good at ...
8
votes
1answer
154 views

Biggest crater in the Solar System

It seems that the biggest crater in the Solar System is Borealis Basin on Mars. The Wikipedia entry and this piece of news say it has been formed by an impact with a body of around 1600 - ...
6
votes
1answer
173 views

What is the orbital path of Omega Centauri?

I was under the impression the only objects relatively close to our Milky Way but not yet a part of it were the Sagittarius Dwarf and Large and Small Magellanic Clouds and then much further out, but ...
0
votes
1answer
134 views

How to find the orbit of a moving point object given 3 past passing positions?

How do I find the orbit of a moving point object given 3 past passing positions and the tangents at these passing positions, and given that the orbit is known to be an ellipse?
-1
votes
2answers
257 views

Need help buying binoculars online for astronomy (10x50) [closed]

After reading much online I've decided to by a 10x50 porro prism Binoculars. The one I have in mind http://www.letsbuy.com/celestron-upclose-10x50-p-34652 has BK7 prisms. The one I would like to buy ...
4
votes
1answer
46 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 ...
14
votes
4answers
10k views

Do all the individual stars that we can see in the night sky belong to Milky Way?

I was wondering if all the stars that we can see with the unaided eye as distinct point sources are from our own galaxy? In other words, can we see stars from the Andromeda Galaxy or other galaxies ...
3
votes
3answers
44 views

Identifying objects, for dummies

If I'm a tyro and have a latitude, longitude, time, date, height from the horizon, and compass direction, what means can I use for identifying what I see there? Realize that, as a tyro, I don't have ...
5
votes
3answers
4k views

Why is 1 AU the distance between the Sun and the Earth?

Why 1 AU is defined as the distance between the Sun and the Earth? (approximately if you like to be precise) An astronomical unit (abbreviated as AU, au, a.u., or ua) is a unit of length ...
7
votes
4answers
156 views

Automated telescope system

I am living up north in Norway, 300 km above the Arctic Circle, which gives me six months per year of darkness and cold. I used to have a starter telescope when I was living in Spain, but I gave it ...
0
votes
1answer
275 views

How to describe the inner curve of a crescent?

What is the equation which describes the inner circle of the crescent that a celestial body displays when view at an angle from its light source, as a function of the crescent-cycle period? For ...
8
votes
4answers
3k views

How can I stabilize an unstable telescope?

I have an 80 mm refractor telescope on a tripod, but it shakes on every touch. It's very hard to see via 6 mm (x120) ocular. Even a little wind causes the image to become too unsteady. How ...
6
votes
1answer
798 views

What telescope would I need to observe Mars's polar caps?

What telescope refractor aperture size would I need to observe Mars's polar caps? I have a Levenuhk Strike NG 80mm, and I can see red disk of planet but cannot see any details on the surface.
0
votes
1answer
221 views

Reflectance of Round Moon vs Flat Moon

Treating the moon as an ideal, bright Lambertian reflector, I was trying to compare its efficiency as a light source to an equally-sized flat sheet of drywall. It's pretty straightforward to set the ...
8
votes
2answers
1k 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 ...
2
votes
2answers
108 views

How bright are auroras (aurorae)?

Digital cameras are making the recent auroras look magnificent, but what are they like to the naked eye? Are they comparable in surface brightness to the Milky Way?
3
votes
2answers
126 views

What is stopping us from stick building a space station?

I want to understand why we do not build space stations in a similar way that we build a home, piece by piece. Instead we construct modules on the ground and fly them up. Are there some technical ...
9
votes
1answer
171 views

Are Uranus and Neptune too big for their location?

So I was watching some TV, and I heard Dr. Plait mention that the planets Uranus and Neptune are too big to be located so far out in our solar system. Now, I heard his explanation on the show as to ...
9
votes
5answers
574 views

sun-moon-earth anomaly

When one looks at the sun and the moon in the sky together, why is it that the illuminated crescent of the moon does NOT "point" at the sun? (More correctly the perpendicular bisector of the straight ...
15
votes
2answers
532 views

Why don't any of the gas giants have moons of Earth's mass (or greater) that orbit them? Is this generalizable to exoplanet gas giants?

Now, we know that the composition of the outer planets tend to contain a much higher ratio of ice over rock. [1] So the lack of Earth-like moons around the outer planets that this could be an artifact ...
2
votes
2answers
182 views

Interstellar bodies

As a solar system evolves the planets interact, and in trying to achieve a harmonious state some bodies are ejected. Space is big, but I have heard that some meteorites have been found with anomalous ...
1
vote
1answer
62 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 ...
4
votes
3answers
809 views

Sky-Watcher Skyhawk 1145P SynScan AZ GOTO

What is the experience using the Sky-Watcher Skyhawk 1145P SynScan AZ GOTO telescope and can it be recommended for a new astronomer? Is it any good?
1
vote
2answers
411 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 ...
9
votes
2answers
3k views

How can the date of lunar eclipses be calculated by hand?

How can the date of lunar eclipses be calculated? Especially without the aid of a computer.
3
votes
1answer
108 views

Looking for a resource that explains all colors and shapes of stars and galaxies

I've been looking at some of the astronomy pictures of the day from NASA. They all have content that is indicative of certain situations or events. Supernovas have the scattered lines look, new stars ...
3
votes
2answers
2k views

Issues with Celestron 130 SLT and shaking

I have a Celestron 130 SLT reflector. I am having some issues with it and I hoped you all could help me. I'm looking for some low tech and inexpensive solutions. My telescope shakes like crazy. I ...
12
votes
3answers
37k views

The Moon during the day

Why do we see the Moon during the day only on certain days and not every day?
10
votes
3answers
206 views

Will the James Webb Space Telescope be able to capture something similar to, or better than, the Hubble Ultra Deep Field?

Will the James Webb Space Telescope (JWST) be able to capture, or ever be used for, anything similar to the Hubble Ultra Deep Field (HUDF)?
5
votes
1answer
4k views

How much sky do we see at any one moment?

When we look at any particular point the sky, what percentage of the celestial sphere do we see? This question arises from the notion that on average there passes one meteor per hour overhead. So ...
2
votes
4answers
790 views

How to locate the Orion Nebula?

I was trying to see Orion Nebula for few days now and I simply can't spot it. I'm using Celestron PowerSeeker 127EQ ( 5" , Newtonian , 1000m ). I'm pretty sure I have the right spot as I saw many ...
3
votes
3answers
140 views

Quality loss when adding more components to a telescope?

I would think this would be inherently true, but I'm curious: (Assuming the highest quality amateur instruments are used.) Is quality lost when, say, adding a T-mount adapter, diagonal or any other ...