Results 1 to 6 of 6
  1. #1
    Francisco Rodriguez-Letters's Avatar
    Francisco Rodriguez-Letters is offline White Dwarf
    Points: 577, Level: 11
    Level completed: 54%, Points required for next Level: 23
    Overall activity: 1.0%
    Achievements:
    2 Posts Achievement5 Threads Achievement!365 Days+ Registered Achievement!
    Join Date
    Nov 2018
    Location
    Qld
    Posts
    4
    Points
    577
    Level
    11
    Thanks
    0
    Thanked 0x 0 Posts

    Lightbulb Big telescope/big sensor versus small telescope/small sensor?



    Hello, I was wondering if someone could help me..
    I have a question that I've had a surprisingly hard time getting to the bottom of. It's very simple: Why do people buy huge telescopes with huge sensors and large pixels when you can get the exact same pixel scale with a small telescope and small sensor and small pixels (with the appropriate size ratio). What is the benefit of the big gear? It seems that the photon density per unit sensor area can easily be made to be the same, as can the viewing angle. I'm strictly talking about astrophotography here.
    There must be a great advantage, because why else would anyone get a 14 inch planewave and 16803 sensor instead of a 100mm refractor and appropriately small sensor.
    Any replies would be greatly appreciated

  2. #2
    KathyNS's Avatar
    KathyNS is online now Super Moderator
    Points: 172,503, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 80.0%
    Achievements:
    200+ Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!First 1000 Experience Points400+ Posts AchievementGot three Friends
    Awards:
    Reply Award
    Join Date
    Nov 2010
    Location
    Nova Scotia
    Posts
    25,147
    Points
    172,503
    Level
    100
    Thanks
    6,658
    Thanked 14,977x 9,536 Posts
    Blog Entries
    3

    Default Re: Big telescope/big sensor versus small telescope/small sensor?

    Well, big pixels would be more sensitive with a higher signal-to-noise ratio. But you should probably find someone who has gear that you are wondering about and ask them why they made the choices they did. With something as personal as geal selection, there are as many reasons as there are astrophotographers. I don't actually know anyone who has big scope / big sensor / big pixels.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    DSO AP:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,LRGB filters; KWIQ/QHY5 guide
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    (pier);
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    .

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  3. #3
    CamelHat's Avatar
    CamelHat is offline Bronze Supporter
    Points: 51,868, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 26.0%
    Achievements:
    50 Posts Achievement!5 Threads Achievement!First 1000 Experience Points2 Posts Achievement20 Posts Achievement!
    Join Date
    Dec 2011
    Location
    Santa Barbara, CA
    Posts
    5,805
    Points
    51,868
    Level
    100
    Thanks
    1,170
    Thanked 1,719x 1,387 Posts

    Default Re: Big telescope/big sensor versus small telescope/small sensor?

    Quote Originally Posted by Francisco Rodriguez-Letters View Post
    Hello, I was wondering if someone could help me..
    I have a question that I've had a surprisingly hard time getting to the bottom of. It's very simple: Why do people buy huge telescopes with huge sensors and large pixels when you can get the exact same pixel scale with a small telescope and small sensor and small pixels (with the appropriate size ratio). What is the benefit of the big gear? It seems that the photon density per unit sensor area can easily be made to be the same, as can the viewing angle. I'm strictly talking about astrophotography here.
    There must be a great advantage, because why else would anyone get a 14 inch planewave and 16803 sensor instead of a 100mm refractor and appropriately small sensor.
    Any replies would be greatly appreciated
    The light flux on the sensor depends on the focal ratio. Since most DSO scopes are roughly around F/5 to F/7 this means that the larger scopes will provide more magnification. You get more detail. Also, the angular resolution is better because of the Rayleigh criterion. Another advantage, some SCTs can be configured to operate at F/2.2, which increases the light flux considerably leading to much shorter exposure times. It is quadratic with the inverse of the F ratio.
    ... Henk. Telescopes: 6" Mak-Newt (Comet Hunter), ES ED127CF, ES ED80, Zhumell Z12, Coulter Odyssey 10, AT6RC, Venture RX-7, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S, AVX, LXD55, Tiltall, Cameras: Fuji X-a1, Canon SX40, Xt, XSi, T6, ELPH 100HS, DIY: Dob and camera barndoor trackers, afocal adapter, Dob with foldable base and Az/Alt setting circles, Accessories: SSAG, Plossls, Barlows, Telrad, laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: DSS, ImageMagick, PHD, Nebulosity, Photo Gallery, Gimp, CHDK

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  4. #4
    yobbo89's Avatar
    yobbo89 is offline HYPER GIANT
    Points: 20,388, Level: 98
    Level completed: 72%, Points required for next Level: 112
    Overall activity: 18.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Gallery Achievement!
    Join Date
    Nov 2015
    Location
    brisbane
    Posts
    2,297
    Points
    20,388
    Level
    98
    Thanks
    141
    Thanked 543x 465 Posts

    Default Re: Big telescope/big sensor versus small telescope/small sensor?

    i see op's question ,example will a 1000 mm fl scope with 2.4um pixel show the same amount detail as a 1600 mm fl scope that has 3.8um pixels once cropped /zoomed to each others image scale.
    scopes :gso/bintel f4 12"trust tube, bresser
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ar127s /
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    10'' dob
    cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7
    mounts : eq6 pro/eq8
    filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, Thousand Oaks Solar Filter.
    extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Corrector,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel

  5. #5
    sdbodin's Avatar
    sdbodin is offline SUPER GIANT
    Points: 21,637, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 16.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!First 1000 Experience Points365 Days+ Registered Achievement!
    Join Date
    Nov 2013
    Location
    Eastern Washington, USA
    Posts
    769
    Points
    21,637
    Level
    100
    Thanks
    863
    Thanked 389x 281 Posts

    Default Re: Big telescope/big sensor versus small telescope/small sensor?

    I guess, then following this logic, the pro's should scrap all those 10 meter monsters and get a Tak 106?? Answer; bigger is better, gathers more photons. Those faint distant targets only send a few photons our way and you need a bigger collecting area to grab them. Photon density doesn't mean much if all you get is background noise, there needs to be signal in there.

    Steve
    Scopes: Meade 16LX200 GPS UHTC, 17.5 Dob, 10 DK, C8, AT80LE, Orion 80SD, couple 6's, couple 4's, Unitron 2.4.
    Cameras: ZWO ASI1600MC-cool, Atik460ex, QHY5L-II mono and color, Orion Starshoot original, Mintron video, couple other LLTV cams.

  6. #6
    yobbo89's Avatar
    yobbo89 is offline HYPER GIANT
    Points: 20,388, Level: 98
    Level completed: 72%, Points required for next Level: 112
    Overall activity: 18.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Gallery Achievement!
    Join Date
    Nov 2015
    Location
    brisbane
    Posts
    2,297
    Points
    20,388
    Level
    98
    Thanks
    141
    Thanked 543x 465 Posts

    Default Re: Big telescope/big sensor versus small telescope/small sensor?

    I guess it make sense on longer fl scopes, you have the seeing resolution ,no point in oversampling it,spend the cash on bigger more sensitive pixels
    scopes :gso/bintel f4 12"trust tube, bresser
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ar127s /
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    10'' dob
    cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7
    mounts : eq6 pro/eq8
    filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, Thousand Oaks Solar Filter.
    extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Corrector,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel

 

 

Similar Threads

  1. APS-C sensor vs Full Frame sensor
    By YsniperY in forum Astronomy Beginners Forum
    Replies: 5
    Last Post: 08-17-2017, 04:01 AM
  2. Full Frame Sensor Vs Cropped Sensor (Canon 6D V Canon 7D)
    By mckechg in forum Astro Imaging Forum
    Replies: 14
    Last Post: 04-19-2014, 01:20 AM
  3. Large telescope vs small telescope
    By PRISMA in forum General Stargazing Forum
    Replies: 7
    Last Post: 03-07-2013, 09:39 PM
  4. Small telescope for grab'n'go doubling as finderscope on larger telescope
    By lordhong in forum Telescope Accessories Forum
    Replies: 8
    Last Post: 11-24-2012, 06:56 PM
  5. Small telescope for use on holiday?
    By Tim Cutts in forum UK Astronomy Forum
    Replies: 9
    Last Post: 06-20-2006, 10:28 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin« Version 4.2.0
Powered by vBulletin«
All times are GMT. The time now is 11:06 PM.