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AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread] Watch

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    (Original post by CD223)
    Jealous. Sounds like I went to the wrong college


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    Probably it's pretty weird to hear people talking about picking where they want to go for sixth form though like what I can only get to one place (the glory of rural areas). It is a very good college but that's just a coincidence really, I go there because it's our college?
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    (Original post by Lau14)
    Probably it's pretty weird to hear people talking about picking where they want to go for sixth form though like what I can only get to one place (the glory of rural areas). It is a very good college but that's just a coincidence really, I go there because it's our college?
    Kinda the same with me really. People travel miles to get to my college (not because it's rural, but because like 4,000 people go there and it has a good reputation) but it's only a 10 minute walk away for me haha!


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    (Original post by CD223)
    Kinda the same with me really. People travel miles to get to my college (not because it's rural, but because like 4,000 people go there and it has a good reputation) but it's only a 10 minute walk away for me haha!


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    Yeah we get a lot of people travelling a long way for our college as well like I didn't even realise it had a good reputation until I was here I had no choice realistically. Like people leave the private schools in the same town to come here instead sometimes. Bit further than a ten minute walk though! (even my grandparent's is a 25 minute walk, we're about a 15 minute drive depending on traffic. Which for me getting to college is 5 minutes car, 10 minutes park and ride because it's a lot cheaper and on the way to work for mum anyway).
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    (Original post by Lau14)
    Yeah we get a lot of people travelling a long way for our college as well like I didn't even realise it had a good reputation until I was here I had no choice realistically. Like people leave the private schools in the same town to come here instead sometimes. Bit further than a ten minute walk though! (even my grandparent's is a 25 minute walk, we're about a 15 minute drive depending on traffic. Which for me getting to college is 5 minutes car, 10 minutes park and ride because it's a lot cheaper and on the way to work for mum anyway).
    Ah it does seem pretty local still!
    What do you happen to know about a Cassegrain reflector?
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    (Original post by CD223)
    Ah it does seem pretty local still!
    What do you happen to know about a Cassegrain reflector?
    Cassegrain reflectors have the secondary mirror directly opposite the primary mirror, reflecting light back through a hole in the primary mirror to an eyepiece, whereas Newtonian reflectors have an angled mirror to reflect light to an eyepiece in the side of the telescope. Basically just a case of where the eyepiece is I think!
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    (Original post by Lau14)
    Cassegrain reflectors have the secondary mirror directly opposite the primary mirror, reflecting light back through a hole in the primary mirror to an eyepiece, whereas Newtonian reflectors have an angled mirror to reflect light to an eyepiece in the side of the telescope. Basically just a case of where the eyepiece is I think!
    Ah thank you! My teacher talked of Newtonian reflectors today - he set us a research task on Cassegrain reflectors. Do both types of reflecting telescopes block out parts of the image by using a secondary convex mirror?
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    (Original post by CD223)
    Ah thank you! My teacher talked of Newtonian reflectors today - he set us a research task on Cassegrain reflectors. Do both types of reflecting telescopes block out parts of the image by using a secondary convex mirror?
    They both have a secondary convex mirror, but our teacher was talking about how they don't block out the image as such (there's not a black blob in the middle) because light comes into the telescope from all directions or the region lost (due to that and the hole in the secondary mirror on Cassegrains) is insignificant or something, it just decreases the amount of light getting in.
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    (Original post by Lau14)
    They both have a secondary convex mirror, but our teacher was talking about how they don't block out the image as such (there's not a black blob in the middle) because light comes into the telescope from all directions or the region lost (due to that and the hole in the secondary mirror on Cassegrains) is insignificant or something, it just decreases the amount of light getting in.
    Oh right!
    So why would you use a cassegrain over a Newtonian or vice versa?


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    I need as many notes as I can for astrophysics, it's hard to take in all those keywords.
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    (Original post by simonli2575)
    I need as many notes as I can for astrophysics, it's hard to take in all those keywords.
    How far into it are you?
    We've done very little. Basically everything past resolving power in lenses is still to come :/


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    (Original post by CD223)
    How far into it are you?
    We've done very little. Basically everything past resolving power in lenses is still to come :/


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    We learned drawing lens diagram, resolving power, distance in parsec, different telescopes (I forgot all of them), chromatic and spherical aberration, Wien's displacement law, Stefan's law, magnitudes, star classes, etc.
    I have the CGP book at least, might it help?
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    (Original post by CD223)
    Oh right!
    So why would you use a cassegrain over a Newtonian or vice versa?


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    I have no clue... the Newtonian would likely put the eyepiece in a more convenient place for actual observing but I can't think of any other reasons and I don't have any in my notes?
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    (Original post by simonli2575)
    We learned drawing lens diagram, resolving power, distance in parsec, different telescopes (I forgot all of them), chromatic and spherical aberration, Wien's displacement law, Stefan's law, magnitudes, star classes, etc.
    I have the CGP book at least, might it help?
    Haha yeah the CGP book is good do you have the AQA textbook too?


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    (Original post by Lau14)
    I have no clue... the Newtonian would likely put the eyepiece in a more convenient place for actual observing but I can't think of any other reasons and I don't have any in my notes?
    Oh right! I'm not sure how much of this research task is just for interest and how much is actual facts we need to recall... Thanks anyway!!


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    (Original post by CD223)
    Haha yeah the CGP book is good do you have the AQA textbook too?


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    Unfortunately no, we only have the one for the compulsory parts (no options A-D), and that's the part I really need.
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    (Original post by simonli2575)
    Unfortunately no, we only have the one for the compulsory parts (no options A-D), and that's the part I really need.
    Ah right! I'll try and PM you the Astro AQA notes when I can


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    (Original post by CD223)
    Ah right! I'll try and PM you the Astro AQA notes when I can


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    Thanks.
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    (Original post by simonli2575)
    Thanks.
    No worries! Gonna email my physics teacher for digital copies now!


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    (Original post by CD223)
    Oh right! I'm not sure how much of this research task is just for interest and how much is actual facts we need to recall... Thanks anyway!!


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    I think you need to be able to draw the Cassegrain set up as well as the Newtonian, but otherwise you only need to know differences/pros and cons for reflectors vs referactors?
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    AND WE ARE OFFICIALLY FINISHED!!! (with the teaching of the course anyway!)
 
 
 
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