ST-8 XME vs.XE

Discussion in 'Legacy Models (ST, STL, etc.)' started by ale.crl, Nov 7, 2019.

  1. ale.crl

    ale.crl Standard User

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    Hello everybody. This is my first post, I am Alessio from Italy. First of all, sorry for my english:D.
    I am a "young" amateur astronomer, I have a 10" newton on equatorial mount, and I would like to start with photometry, so I am looking for some SBIG ccd camera...I red a lot of good comments about that...
    Right now I am in negotiation for used ST-8 XME and a ST-8 XE, both NABG, what is the difference? I know that M stands for Microlens, it means more sensibility, is it something really needed?
    I have their serial number for the XME, it is 09081700, can anyone tell about its history (when produced, if repaired...)?
    Are these cameras good for my telescope? What would be a reasonable delta cost between XME and XE?
    Thank you.
     
  2. Colin Haig

    Colin Haig Staff Member

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    The ST-8 XME version will give you brighter images in less time. The microlenses concentrate the light on the pixels, and they also improve the viewing angle (not too relevant for your scope). The XME is better than the XE. The camera was manufactured 10 years ago.
    You didn't say what focal ratio your scope is. Assuming f/6, you might want something with smaller pixels, close to 5 or 6um.
    Why are you looking at NABG ? Doing photometry?
    If not, an ABG camera is fine, and something like the STF-8300 would be a better choice for that scope. Even if you are doing photometry, the ABG cameras work fine as long as you don't saturate the chip - stay under 70% full well depth use - eg a bright star will bloom, but if it is not in the region of interest, it's fine.

    Here's a recommendation - being mindful of pixel size and at a budget price:
    http://diffractionlimited.com/product/stf-8300/

    The ST-8XME successor is based on the newer 1603 sensor here:
    http://diffractionlimited.com/product/stf-1603m/

    If you are serious about photometry, if you can find an ST-10XME or the modern version, the 3200 sensor is highest performance and pixels are 6.8um:
    http://diffractionlimited.com/product/stf-3200m/

    We can't give pricing advice on used equipment - totally dependent on the condition it is in. Usually the power supplies fail when the capacitors dry out, and we don't have a replacement power supply.
    Good luck.
     
  3. ale.crl

    ale.crl Standard User

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    Hi, thank you for reply. Finally I got a used ST8-XME which fit with my budget, I wnt to use to do photometry with my Newton f/5.
    Its serial number is 08031589, just for curiosity, when was it manufactured?
    Then, by CCDops5, the Camera Info tab says that it is with ABG, I am little bit surprised, is this info correct?
    Thank you.
     
  4. Doug

    Doug Staff Member

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    Manufactured April 2008. The database says it is ABG.

    The ABG/NABG thing is a bit overblown. Usually it doesn't go nonlinear until very close to saturation. Every camera goes nonlinear at saturation!

    You can check the linearity fairly easily by doing a sequence of exposures and measuring the total intensity of a star at different exposure times. Then plot a graph.
     
  5. ale.crl

    ale.crl Standard User

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    I did a very quick linearity check (just putting the camera in front of a white illuminated panel, with a pinhole over the nosepiece), and it seemed to be linear until around 45000 ADU. I can also say that the more illuminated pixel (a spot in a dark background) clearly showed at longer exposures the blooming effect.
    I will do again more accurately (by averaging several images), but I would like to know if this camera would be fine to start with photometry and what would be the difference with a NABG one. (Let's say that the seller said it was NABG...)
     
  6. Doug

    Doug Staff Member

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    As long as you stay in the linear region it will be perfectly good for photometry.

    The linear region is good almost to saturation on NABG sensors.
     

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