Galaxy Zoo Talk

#3 How do I: All your FAQ's - Includes a GZ Glossary

  • Capella05 by Capella05 moderator

    I have received quite a few questions with regards to Talk, so I thought it will be better to have a separate FAQ thread.

    I will start off addressing the most common ones, and then I will hand the thread over to you guys - the other mods and myself will be available to answer your questions 😃

    .

     Before I start one final important notice about classifying: 
 Always classify the image directly at the center, and ***never*** try to avoid a really hard image. 
 It does not matter if you can't make heads or tails out of it- just try your best.  
 We will learn more from the jumbles of classifications than if it was never classified.

    .

    Posted

  • Capella05 by Capella05 moderator

    Where can I change my avatar?

    To change your avatar on Talk:

    2015/10/20 This has been edited to take into account recent Zooniverse account changes:

    • Click here to access your Zooniverse account.
    • Select 'Customize Profile' if necessary.
    • Drop a new Avatar into the box 😃

    Posted

  • Capella05 by Capella05 moderator

    How do I post a picture?

    Method 1:

    • Right click on the image, a popup menu should appear.
    • Select 'Copy Image URL'
    • Select the 'Image' icon from the discussion toolbar (or Ctrl +G).
    • Paste the image URL, leaving the 'http://' (see below).
    • Click on preview to see if the image is displayed.

    FAQ1

    Method 2:

    Paste the URL of the image into the following code. This method allows you to control the height and width of the image. Very useful!

    <IMG SRC="http://i1203.photobucket.com/albums/bb397/xxx/FAQ1_zps294f4353.png" WIDTH="500" HEIGHT="374">

    Posted

  • Capella05 by Capella05 moderator

    How do I post a hyperlink?

    • Copy the URL address that you would like to link to.
    • Click on the 'Hyperlink' icon on the toolbar or select [Ctrl + L]
    • Paste the URL address,so it looks like the image below.
    • Add a description between the square brackets.

    .

        [Link to Zoocon 2014](http://talk.galaxyzoo.org/#/boards/BGZ0000002/discussions/DGZ0000uqy)

    Posted

  • Capella05 by Capella05 moderator

    Where can I find my favourites that I have classified?

    Your favourites (and all the images you have classified) can be found over on Galaxy Zoo Classify.

    • Either click on the 'Return to classifying' button in the top right, or click here
    • Then select the 'Profile 'hyperlink' in the top right.
    • The page will automatically default to the recent images you have classified, to get to your favourites, select the favourite tag on the mid left.

    .

    Posted

  • Capella05 by Capella05 moderator

    Glossary : Artifact

    An artifact can be described as "something observed in a scientific investigation or experiment that is not naturally present but occurs as a result of the preparative or investigative procedure" [1]

    In other words, they are not real. They are caused by the equipment we are using to image galaxies.

    In the case of the images we are classifying on Galaxy Zoo, most of the artifacts we encounter are down to imaging errors - the filters on the telescope could be misaligned, the observing conditions could be marginal (eg. very windy / high humidity / high cloud etc...) or there could be another bright object in the FOV that overpowers the galaxy we are trying to image. That is why we are so good at classifying images, we can easily tell apart a artifact from an actual object. Algorithms cannot do that.

    Some common examples:

    [Artifact](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=1&comment_id=54708389415ac121e30001ee)
[Artifact](http://tinyurl.com/kff9xay)

    [1] Google on-line dictionary

    Posted

  • Capella05 by Capella05 moderator

    Glossary : 'Over Saturation' or 'Over Exposure'

    "Overexposure in photography refers to an image where too much light was recorded. The degree of overexposure will determine how bright a photo is." [1]

    I do not know the origins of the term on Galaxy Zoo, but we tend to use the word 'oversaturation' to describe an artifact caused by the brightness of a specific object. It is most noticeable in foreground stars and AGN's. With galaxies it can present itself as a dark dot within the galactic core.

    Examples:

    [oversaturation](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=1&comment_id=54708ce027b5623ad30002d2)
[oversaturation](http://tinyurl.com/nt5asta)

    [1] A Glossary of Photography Terms

    Posted

  • Capella05 by Capella05 moderator

    Glossary : Foreground star

    Exactly what is says on the tin 😃 A foreground star is a star from our own galaxy - The Milky Way. Since we are having to view distant galaxies through our own galaxy, stars sometimes get in the way. The images we are classifying are one dimensional, so it is sometimes difficult to determine the distance of an object, and whether it belong to our galaxy or not.

    Rule of the thumb - stars tend to have a more cleanly defined edge than galaxies. Galaxies are fuzzy - not surprising as they are made up of billions of stars. Foreground stars also tend to display a lot of artifacts such as diffraction spikes.

    Examples:

    [foreground stars](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=1&comment_id=5470a7dc415ac11e720004c6)
[foreground stars](http://tinyurl.com/pc5goso)

    Posted

  • Capella05 by Capella05 moderator

    Glossary : Diffraction Spike

    Definition: "Diffraction spikes are lines radiating from bright light sources in reflecting telescope images. They are artifacts caused by light diffracting around the support vanes of the secondary mirror." [1]

    Most of the images we classify are from the The Sloan Foundation 2.5-m Telescope situated in New Mexico (image below). If you look closely, you can see the support vanes - there are four of them, situated 45 degrees off the horizontal / vertical axis. It is these supports that cause the diffraction spikes we see around really bright objects such as stars.

    Copyright © 2010-2013 SDSS-III

    Examples:

    [diffraction spike](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=1&comment_id=5471e3f327b562489c00036d)
[diffraction spike](http://tinyurl.com/nd5xu8n)

    [1] Source: Wikipedia

    Posted

  • Capella05 by Capella05 moderator

    Glossary : Overlap

    In the context of Galaxy Zoo we use the term 'overlap' to describe galaxies that are overlapping but not interacting. In other words, they are at different distances (from our view point), but due to line of sight they appear to overlap each other. The usage of the term first came about when Dr Bill Keel created a thread asking us to keep an eye out for them.

    Why is it so important? (from the forum)

    Why? In a word, dust. Dust grains play a crucial role in the evolution of galaxies and in how we see them. Dust intermingled with interstellar gas helps it cool to form stars, and in turn these grains are produced in the atmospheres of cool stars and in the expanding envelopes of nova and supernova explosions. Dust reddens and dims starlight passing through it, to an extent that increases for bluer and ultraviolet light (just as particles in our atmosphere do for sunrise and sunset). We need to correct for this effect if we are to understand the star-forming history of galaxies, one of the most important ingredients to cosmic history. One of the most straightforward approaches to this problem is use of silhouetted galaxies, in which we see one galaxy partially backlit by another. The ideal case is a spiral half projected against the smooth light of an elliptical or lenticular galaxy. However, we need to look at spiral/spiral overlaps as well, since looking at the high-redshift Universe and comparing with deep Hubble observations means that we need to look into the ultraviolet(which has been shifted into visible light by cosmic expansion for such distant galaxies). Ellipticals and lenticulars are quite red, and too dim in the UV to be effective backlights. With a list in hand of the best local galaxy pairs for this project, we can initially extend these measurements into the UV using the ongoing survey by the GALEX satellite, which is in many ways a good match for the Sloan data. Eventually it is our hope to extend the project to include followup with such other facilities as Hubble. This approach dovetails with measurements of the dust in the far-infrared, but we are still some way from having the sensitivity to do such measurements wholesale in the early Universe at a level sensitive enough to match what the absorption technique does. Furthermore, to say something about the whole population, we need to start with enough pairs for a wide range of galaxy type and luminosity to be represented. Just the thing for GalaxyZoo. (Dr William Keel)

    Examples:

    [overlap](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=1&comment_id=5472079927b562063b000050)
[overlap](http://tinyurl.com/nbaxkzk)

    Posted

  • chairgaf by chairgaf

    OK. Maybe a stupid question, since I have been with G/Z for some time, but I feel I still need to ask.

    How are we to determine if the multiple galaxies we see, are either overlap, or merger.?

    Posted

  • Capella05 by Capella05 moderator in response to chairgaf's comment.

    Hi @chairgaf,

    I am still in the process of writing up all the FAQ's - I work full time, so I only get the chance to do it in my free time. I will make sure to add some merger vs overlap classifying tips when I write the merger FAQ.

    There is no such thing as a stupid question 😃

    Posted

  • Capella05 by Capella05 moderator

    Glossary : Merger

    Galaxy mergers can occur when two (or more) galaxies collide. They are the most violent type of galaxy interaction.

    Source: Wikipedia

    One important area of research in astronomy studies the role of interacting galaxies. Interacting galaxies are galaxies that exhibit a gravitational influence on one another. This influence is exhibited over the course of millions or even billions of years as two or more galaxies pass nearby one another. The near passage of two massive structures can cause the galaxies to be distorted and possibly merge.

    Source: Galaxy Zoo Mergers

    Here is another excellent article from the SDSS website with more information on galaxy mergers: Galaxy Collisions

    Sometimes it is difficult to tell the difference between galaxy mergers and galaxy overlaps. So when classifying a possible merger you need to ask yourself the following questions:

    • Are the galaxies distorted? Do we have tidal tails?
    • Are there signs of star formation or starbursts?
    • Do the galaxies have a similar redshift?
    • In the absence of redshift, what about the PhotoZ? If that is not available, what about the colour of the galaxy - are they similar?

    Examples:

    [Merger](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54846df727b5625278000025)
[Merger](http://tinyurl.com/ove4l9v)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: FOV = Field of View

    In photography, the field of view is that part of the world that is visible through the camera at a particular position and orientation in space; objects outside the FOV when the picture is taken are not recorded in the photograph.

    Source: Wikpedia

    In astronomy the field of view is usually expressed as an angular area viewed by the instrument, in square degrees, or for higher magnification instruments, in square arc-minutes.

    Source: Wikipedia

    We would use this term on GZ Talk when referencing objects that are in the image that you classified, that are not the central object.

    Why is this necessary? It is important for us to make the distinction between the two, as you should only ever classify the central object. It is okay to discuss any other interesting objects you see in Talk, but to make it less confusing to other volunteers, we need to be specific about what we are discussing.

    .

    Example: "The other objects in the FOV are foreground stars"

    [FOV](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=5490736e27b562534f00073e)
[FOV](http://tinyurl.com/pbbahaz)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: SkyServer

    From the SkyServer website:

    SkyServer is the catalog data access site for the Sloan Digital Sky Survey-III. From this site, you can view all the catalog data - measuremed quantities like positions and magnitudes - for all the stars, galaxies and quasars in the SDSS-III's Data Release 8.

    Instructions on how to access SkyServer can be found in this thread: #1 How do I : Find out more information about the galaxy I have classified?

    There are excellent training resources on the SkyServer website to get you started - highly recommended!

    [SkyServer](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54ba37169cd11867be00000e)
[SkyServer](http://tinyurl.com/kfsl3vg)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: AGN = Active Galaxy Nucleus

    Definition: Encyclopedia Britannica

    Active galactic nucleus (AGN), small region at the centre of a galaxy that emits a prodigious amount of energy in the form of radio, optical, X-ray, or gamma radiation or high-speed particle jets.

    Definition: Wikipedia

    An active galactic nucleus (AGN) is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum.

    In the images we are classifying we see AGN's as really bright cores in galaxies. The brightness may cause some optical artifacts such as oversaturation. Depending on the current survey they tend to have a very distinct colours - more info on the colours in Budgies AstroPhysics for GZ thread. In order to classify a galaxy as having a AGN a spectra is needed.

    Feel free to tag confirmed AGN as #AGN, the ones you suspect as being an AGN tag as #AGNp (p meaning possible).

    Examples:

    | AGZ000311s | AGZ00065l1 | AGZ0002w7d | AGZ0001lng | AGZ0002sfs |

    [AGN](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54ba5b28bb7b563662000158)
[AGN](http://tinyurl.com/mz79nl2)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: Asteroid

    Definition: Oxford English Dictonary

    A small rocky body orbiting the sun. Large numbers of these, ranging enormously in size, are found between the orbits of Mars and Jupiter, though some have more eccentric orbits.

    From the GZ Talk New to Galaxy Zoo? Want Help? Read this!

    Asteroids also move across these images, albeit more slowly than satellites. So when each of the filters that make up the image colors takes data in succession, the asteroid looks like a multicolored stripe (or series of dots) across the image. - Vrooje

    Examples:

    | AGZ0001gm5 | AGZ0001gn0 | AGZ0001xnb | AGZ0003f74 | AGZ0004xay |

    [Asteroid](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54bea13b29a6f6041500062b)
[Asteroid](http://tinyurl.com/ktg277l)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: Satellite Trail

    Definition: Wikipedia

    In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon.

    From the GZ Talk New to Galaxy Zoo? Want Help? Read this! thread.

    Satellites sometimes pass overhead as the telescope is observing and reflect light in a streak across the image as they pass by. They move quickly so their trails are always a single color: red, green, or blue. - Vrooje

    Examples:

    [Satellite Trail](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54df22c2832cec18ff00016b)
[Satellite Trail](http://tinyurl.com/munme52)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: Satellite Galaxy

    Definition: Wikipedia

    A satellite galaxy is a galaxy that orbits a larger galaxy due to gravitational attraction... In a pair of orbiting galaxies, if one is considerably larger than the other, then the larger is the "primary" and the smaller is the satellite. If two orbiting galaxies are about the same size, then they are said to form a binary system.
    Galaxies which encounter one another from certain directions may interact: collide, merge, rip each other apart, or transfer some member objects. In these situations, it can be difficult to tell where one galaxy ends and where another begins. "Collisions" between galaxies do not necessarily involve collisions between objects from one galaxy and objects from the other, since galaxies are mostly empty space.

    Our own galaxy - The Milky Way - has several satellites galaxies - you can read more about them here.We usually see satellite galaxies as as a smaller blured and undefined object next to a larger galaxy.

    [Satellite Galaxy](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54df28926975263c8b000473)
[Satellite Galaxy](http://tinyurl.com/k4dhw6q)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: NED = NASA/IPAC Extragalactic Database

    From the NED website:

    NED is a comprehensive database of multiwavelength data for
    extragalactic objects, providing a systematic, ongoing fusion of
    information integrated from hundreds of large sky surveys and tens of
    thousands of research publications. The contents and services span the
    entire observed spectrum from gamma rays through radio frequencies. As
    new observations are published, they are cross- identified or
    statistically associated with previous data and integrated into a
    unified database to simplify queries and retrieval. Seamless
    connectivity is also provided to data in NASA astrophysics mission
    archives (IRSA, HEASARC, MAST), to the astrophysics literature via
    ADS, and to other data centers around the world.

    A really useful tool when trying to find out more information about the object you have classified! Read this thread here for instructions on how to access NED from GZ Talk.

    [NED](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=2&comment_id=54e87060832cec0623000003)
[NED](http://tinyurl.com/kef4d8c)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: SIMBAD = Set of Identifications, Measurements and Bibliography for Astronomical Data

    The SIMBAD database is managed by the Centre de Données astronomiques de Strasbourg (CDS), and originally started out as as database for stellar objects, and was later expanded to include all astronomical objects. You can access the SIMBAD database via SkyServer.

    Go to the website for more info and a user guide.

    [SIMBAD](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=3&comment_id=54e8758f832cec0b2f000063)
[SIMBAD](http://tinyurl.com/p9onwu7)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: SDSS = Sloan Digital Sky Survey

    From the SDSS DR1 website:

    Simply put, the Sloan Digital Sky Survey is the most ambitious
    astronomical survey ever undertaken. The survey will map one-quarter
    of the entire sky in detail, determining the positions and absolute
    brightnesses of hundreds of millions of celestial objects. It will
    also measure the distances to more than a million galaxies and
    quasars.

    And from the SDSS DR12 website:

    The Sloan Digital Sky Survey has created the most detailed
    three-dimensional maps of the Universe ever made, with deep
    multi-color images of one third of the sky, and spectra for more than
    three million astronomical objects. Learn and explore all phases and
    surveys—past, present, and future—of the SDSS.

    Since Galaxy Zoo's inception a lot of the images we have classified have come from SDSS. If you are interested in where and how the images come about, I highly recommend going to their website. For convenience I will list a few of my favourite SDSS links below.

    .

    [SDSS](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=3&comment_id=54e87ce66975265850000197)
[SDSS](http://tinyurl.com/qzojr22)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: UKIDSS = The UKIRT Infrared Deep Sky Survey

    From the UKIDSS website:

    UKIDSS is the next generation near-infrared sky survey, the successor
    to 2MASS. UKIDSS began in May 2005 and will survey 7500 square degrees
    of the Northern sky, extending over both high and low Galactic
    latitudes, in JHK to K=18.3. This depth is three magnitudes deeper
    than 2MASS. UKIDSS will be the true near-infrared counterpart to the
    Sloan survey, and will produce as well a panoramic clear atlas of the
    Galactic plane

    [UKIDSS](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=3&comment_id=54e8b4ee832cec2189000938)
[UKIDSS](http://tinyurl.com/lsxj5qj)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: Starbursts / Star Formation

    Star formation or Star Bursts are dense compact regions with an intense luminosity seen within a galaxy - they will usually be a vivid blue or green in colour. The colour will be dependant on the the survey you are currently classifying and remember all the colour in telescopic images we classify is artificial!

    Stars form when molecular dust clouds collapse under the force of gravity to create a protostar - they are young and hot, and this leaves tell tale signs in both the colour and spectra of a galaxy.

    Star formation can also be triggered by interacting or merging galaxies.

    The term 'Starbursts' tends to be reserved for more intense star formation regions or galaxies.

    | AGZ0002d9i | AGZ0005uas | AGZ0002zcx | AGZ0002kly | AGZ00048sj |

    [Star Formation](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=3&comment_id=550ee3e705137051dd000224)
[Star Formation](http://tinyurl.com/pejhfhb)

    Posted

  • Capella05 by Capella05 moderator

    Glossary: Irregular = Irregular Galaxies

    This is sometimes a confusing one 😃

    When extra-galactic astronomers refer to irregulars - they are talking about a class of galaxy. Not necessarily an observation of the shape of a galaxy.

    Irregular galaxies are blue, irregular in shape, with loads of star formation.

    They do not have have any of the distinguishable features of either spiral or elliptical galaxies.

    .

    | AGZ0002zgg | AGZ0002kuj | AGZ0004x1n | AGZ0002v2a |

    [Irregular](http://talk.galaxyzoo.org/#/boards/BGZ0000005/discussions/DGZ0000x8e?page=3&comment_id=550f0569fde6982f620003ea)
[Irregular](http://tinyurl.com/pwad4t5)

    Posted

  • bernoullilemniscate by bernoullilemniscate

    Is there anyway I can find the number of galaxies I have classified? I have have been putting all the galaxies I have classified in my "favorites" but the number listed seems to have maxed out at 1000.

    Posted

  • Capella05 by Capella05 moderator in response to bernoullilemniscate's comment.

    You can see the number of classifications you have done on your Zooniverse profile page - here is a link

    Posted

  • Freethesouls by Freethesouls

    Why not skip a galaxy? Someone mention a skip button for images on planet Four....Well I think a skip button would be nice for all of the zooniverse science projects or some. And a feature like "Be a martian" by NASA where one can write a short note of what seems to be interesting in the pic. Just a box to write notes in.

    Tom Free The Souls

    Posted

  • Freethesouls by Freethesouls

    Is there a feature suggestions area I can not seem to find it but I think a chat room for galaxy zoo would be nice.

    Posted

  • Capella05 by Capella05 moderator in response to Freethesouls's comment.

    Hi Tom,

    Each of the Zooniverse projects works slightly differently to each other - so what might work on Planet Four will not necessarily be advisable for GZ. It was decided ages ago that a skip button was not necessary, as even the slightest bit of information (for example: the galaxies is not smooth) is more helpful than none at all.

    Text boxes would be too labour intensive, as you would need a person to read the input instead of an algorithm. So, if you see anything interesting in the image, flagged it as 'Something Odd' when classifying. You can always make a comment or create a discussion here on Talk and one of the Moderators / Scientists will see it.

    There is a 'Just Chat' section and thread on Talk for all out chit chat - but Talk is not always a hive of activity 😃

    Hope this helps!

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Hi Capella05, ive read the post on changing your avatar and tried all possibilities, but still it won't change. I can see it in Zooniverse but not GZ, Any clues what to do? Thank you in advance,

    Posted

  • Capella05 by Capella05 moderator in response to Ghost Sheep SWR's comment.

    I wrote that before the 'New Zooniverse' platform came about.

    Give me a few minutes and I will let you know 😃

    Posted

  • Capella05 by Capella05 moderator

    Oohhh, I see what you mean.

    None of the old links work any more - give me five and I will have it documented 😃

    Posted

  • Capella05 by Capella05 moderator

    Go to https://www.zooniverse.org/settings/profile/ and follow the instructions - let me know if you need more help!

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Yes i did that several times, works fine in Zooniverse. Either link between Zooniverse and GZ is bust or something with picturesize. Ah well not that important, galactic work to do 😉

    Posted

  • Capella05 by Capella05 moderator in response to Ghost Sheep SWR's comment.

    Have you tried clearing your browser cache? First and last resort?

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Oof, uh iPhone? (I always erase browser history)

    Posted

  • TheMagnificentPeter by TheMagnificentPeter

    Are bars found only in spiral galaxies? All of the examples of bars are accompanied by spirals (but not necessarily vice versa). Also, I see a few galaxies that I would classify as smooth but they have bar-shaped bright centers. How should these be classified?

    Posted

  • ElisabethB by ElisabethB moderator

    Hi TheMagnificentPeter and welcome to Galaxy Zoo

    Bars can also be found in lenticular galaxies (see wiki : https://en.wikipedia.org/wiki/Lenticular_galaxy)

    if you see a 'smooth galaxy with a bar it is most probably a lenticular galaxy.

    Remeber : smooth means no features whatsoever ! 😄

    Happy hunting ! 😄

    Posted

  • allengriesbach by allengriesbach in response to Capella05's comment.

    Does an old star have a different shape than one just being born and does it really matter when your classiying galaxies? Galaxies have alot of stars so whats the circular object in the center of the image?

    Posted

  • Budgieye by Budgieye moderator in response to allengriesbach's comment.

    All stars are round in our images The actual size of a star is less than a pixel wide, they look like round disks because their light spreads out in a round pattern. There is sometimes a nebula around a star. Stars are formed in regions of hydrogen gas, and explode leaving "clouds" of dust and gas.

    Just ignore stars in the foreground when you classify galaxies. The exception is if the star looks blue-green - it might be a supernova.

    The center of elliptical galaxies often have a bright star-like nucleus. But it is not a star.

    Spiral galaxies have clumps of star-forming areas, which look like stars, but are actually thousands of stars in a group.

    Hope this helps.

    Posted

  • victor_muteti by victor_muteti

    Hello, How can someone make suggestions on how to improve sdss current and future projects

    Posted

  • Budgieye by Budgieye moderator

    Suggestions: first start a talk in the Help thread, and outline your thoughts.

    Posted