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Stargazing What is Hubble's field of view?

  1. Aug 29, 2016 #1
    I have a questions about standard measurements of galaxies as it pertains to the following few sentences. In a description of a Hubble ultra deep field view, it is stated that "The HUDF focused on a small region of space in the constellation Fornax and produced an image containing 10,000 distant galaxies in a field of view some 2.4 arcminutes on each side." Is the angular measurement based on the the focal point of the Hubble telescope, comparable to the eyepiece of an amateur telescope?
     
  2. jcsd
  3. Aug 29, 2016 #2

    Drakkith

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    Staff: Mentor

    I'm not sure what you're asking. The angular measurement can be calculated using the focal length of the HST and the size of the sensor. The angular FOV of an eyepiece can be found in a similar manner. Is that what you were asking?
     
  4. Aug 30, 2016 #3
    If this is of interest... From one of Hubble's FAQ pages:

    "If the Hubble Space Telescope pointed to Earth, what resolution would the images have?
    Hubble's so-called angular resolution — or sharpness — is measured as the smallest angle on the sky that it can resolve (i.e. see sharply). This is 1/10 of an arcsecond (one degree is 3600 arcseconds). If Hubble looked at the Earth — from its orbit of approximately 600 km above the earth’s surface — this would in theory correspond to 0.3 metres or 30 cm. Quite impressive! But Hubble would have to look down through the atmosphere, which would blur the images and make the actual resolution worse. Unfortunately, Hubble will never be turned towards Earth since a) the brightness of the Earth could be damage the telescope and its instruments; b) there is no particularly interesting astronomical research to be done there (this is the province of geophysics); and c) Hubble orbits the Earth at such a rate that any image it took would be blurred by the motion.
    "

    "How are the Hubble images in the image archive created?
    Like any modern telescope, Hubble captures images on a digital device that transforms photons into electrons; and the latter carry no colour information. However, filters placed in front of the camera only allow for specific kinds of light (blue or green light, infrared light or ultraviolet radiation) to pass through them and into the camera. Therefore, most of the images found on spacetelescope.org are actually a combination of several identical images, each taken through a different filter. To create the final image, these individual images are coloured — depending on the type of light they represent — and then combined with the others. We colour the images as accurately as possible to correspond with the filters, but sometimes this is not entirely possible. For example, we can not accurately represent those colours invisible to the human eye, such as infrared and ultraviolet light. Therefore, in this case, the filters are represented by colours we can see — though the final image does not represent what the human eye would see if it looked upon the subject in the night sky. Data from Hubble is also contaminated with defects, such as bright pixels — caused by high-energetic particles — and dead pixels, which no longer collect light and noise. These defects are removed to create those images released to the public.
    "
     
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