FAQ

What if I give the wrong answer?

Don't panic! We take the final answer as the consensus of the answers from multiple people. So if you make a mistake, it will not affect the final answer. Just try and answer as best you can. All of your clicks are extremely useful to us!

Why can't a computer do this?

All the images you get have already been selected by a computer. However, teaching a computer to do what we humans do is not easy! As we get more and more images classified having real events or not we can actually teach the computer to a better job!

What are the 3 images?

The left-hand image (New) is a recent picture, taken in the last few hours or days. The middle image (Reference) is an older picture of that same part of the sky, taken when we thought the supernova had first exploded. The right-hand image (Difference) is the "subtraction" of these two images, allowing us to remove other stars and galaxies that haven't changed from the image.

Sometimes the supernova is still quite faint and it is hard to see it in the new image, the subtraction or difference images allows us to find it!

How big are the images?

Each image is 1 arcminute by 1 arcminute. There are 60 arcminutes in 1 degree, and for reference, the full Moon is about half a degree across.

What if I see the candidate in a larger bright structure?

The larger bright structures are galaxies. Some galaxies have a central core that can vary in brightness, an Active Galactic Nuclei, which are also transient objects like supernovae!

What is a Subtraction?

The Subtraction or Difference image is the right-hand image. It is formed by subtracting the light in the Reference (middle) image from that of the New (left) image to see what has changed.

What are the ring or halo-like objects?

If the telescope was out of focus during the exposure, stars and galaxies can appear warped into the ring or halo-like objects you see.

Why are the images not in colour?

The images are observed through a colour filter placed on the telescope. The grayscale image indicates the number of photons that passed through the filter and were detected by the CCD.

What does all the metadata mean?

CandidateID: Our unique identifier for each image

ObjectName: A smaller, more easily readable id for each object, which doubles as its name.

I think I’ve discovered something! What now?

We hope you’re right! If enough people agree with your discovery then we will look at it to confirm your discovery. If it is a candidate we will send it off to get a spectrum of the object, which will tell us what kind of transient it is. To speed this process up, you can post in the Objects board, telling us the CandidateID (found in the metadata of the image) of the image and why you believe it is a discovery.

Do I get any credit for my discoveries?

If you are one of the first to contribute to the discovery of a supernova or transient event we will add you to the public notices we send to the Transient Name Server (TNS). We will also add a list of discovery contributors to our webpage. You have of course to be logged in to get credit (that is the only way we can know your username).

What is this project about?

We are looking for supernovae, stellar explosions that shine very brightly and then fade away, using the SkyMapper Telescope in Australia. For that we use thee types of images, a recent one, an old one and the difference between them. If a new "bright" object can be found in the difference and recent image, you may have found a supernova!

How often are new images added to the project?

We aim to add images as soon as we get them from SkyMapper. If we have good weather this should happen almost every day. Beware that sometimes we get several cloudy nights in a row, after all we are on Earth!

What are transient events?

Transient events are astrophysical phenomena that change brightness in time. A supernova, as the explosive death of a star, are transient events. In the SkyMapper images in this project you can also find: Active Galactic Nuclei in the centre of galaxies, variable stars and other types of transient events!

How long do scientific discoveries take?

Scientific discoveries often hit the news headlines, however these reports of major discoveries often come many months - or even years - after the discovery itself. The reasons for this include the need to verify new discoveries - in the case of this Zooniverse project, a new supernova - as well as the time required for the scientific publication reporting a significant new discovery to pass through the peer review process.

Interesting transients discovered by citizen scientists in this project won’t immediately be reported as supernovae. The SkyMapper team must “follow up” transients flagged by citizen scientists. This involves scheduling repeat observations of the transient with both SkyMapper and a telescope which can obtain a spectrum of the transient. These observations allow us to confirm what type of transient has been discovered. Once the transient has been confirmed as a supernova, the discovery will be reported to the Transient Name Server - an online database of supernova events. The first Zooniverse citizen scientists who discover the supernova will be credited on the Transient Name Server.  A list with all people that discover the supernova will be available online.

Many of the transients discovered through the SkyMapper survey will not be reported in individual scientific journal articles. However, if a particularly unusual supernova is discovered, an individual journal article may be written by the SkyMapper team. If this is the case, citizen scientists will be credited in an online author list associated with the journal article. However, it may be months until such a publication passes peer review and appears in a scientific journal.

Can I track the weather at the Observatory?

Yes, there is a SkyMapper weather station!

What does the astrophysics jargon mean?

Scientific Notation:

In astronomy we deal with very big numbers, for instance the distance to the sun, 150 million kilometers, could also be written as 150,000,000 kilometers. If we scale that up to the distance from the Sun to Pluto we have 5.9 billion kilometers or 5,900,000,000 kilometers! All those zeros can get tiresome to keep writing down so we have two methods of dealing with this. The first is to change the units, for instance when talking about distances within the Solar System we often use Astronomical Units (AU) where 1AU is the distance from the Earth to the sun. In this way we can write the distance to pluto as about 30AU which looks much nicer. Another method is to use scientific notation, which changes 5,900,000,000 to 5.9*10^9 or 5.9 times 10 to the power of 9. The number you raise 10 to is a the number of numbers after 5 (or whatever the first number is).

• 1 Trillion = 1,000,000,000,000 = 10^12
• 1 Billion = 1,000,000,000 = 10^9
• 1 Million = 1,000,000 = 10^6
• 1 Thousand = 1,000 10^3
• 1 Hundred: = 100 = 10^2

Degrees, Arc-minutes, Arc-seconds:

Many coordinate systems in astronomy rely on radial coordinates such as degrees. This is generally done by dividing the sky into 360 equal parts (Degrees). Unfortunately, objects in the sky are very often closer than 1 degree to each other. So each degree is split further into 60 equal parts (Arc-minutes) and each of those further split into 60 equal parts (Arc-seconds). As a reference scale, the full moon is roughly half a degree wide or 30 Arc-minutes.

Hours, Minutes, Seconds:

A similar method of splitting the sky up is into 24 equal part (Hours) each of which is again split into 60 parts (Minutes) and further split into another 60 parts (Seconds). As a reference scale, the full moon is roughly 0.03 hours wide or about 2 minutes.

RA / Right Ascension:

The astronomers equivalent to longitude. Just as longitude has its zero point at the Greenwich Meridian, right ascension has a zero point at the position of the Sun at its peak on the vernal equinox on March 21st. Right Ascension is commonly measured in Hours (h), Minutes (m), Seconds (s) (not arc-minutes and arc-seconds) from 0h0m0s to 24h0m0s.

Dec / Declination:

Just as RA is a longitudinal equivalent, Declination is a latitude equivalent. Declination is measured in Degrees (d), Minutes (m), Seconds (s) from -90d0m0s to 90d0m0s. Declination is 0d0m0s at the equator, +90d0m0s at the North Pole and -90d0m0s at the South Pole. When combined with Right Ascension this gives us a coordinate system that can be used on the sky.

Apparent Magnitude

Apparent Magnitude is a measure of the brightness of an object as seen by an observer on Earth. Confusingly, the brighter the object the lower its magnitude, with really bright objects like our Sun having a negative magnitude (-27). A magnitude of 0 equates to the brightness of Vega the fifth brightest star in the sky as Vega has a very consistant brightness. The magnitude scale is logarithmic with a difference of 1 magnitude equating to a difference of the 5th root of 100 (about 2.512). So an object with magnitude 0 is 2.512 times bright than an object of magnitude 1. Objects with magnitudes of more than 6.5 (0.25% the brightness of Vega) are not visible to the human eye. Planet 9 is expected to have a magnitude between 17 and 25 (1.5*10^-9% to 10^-14%), which is one of the reasons it has been so difficult to find.