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Thread: Just for fun.... Telescope test

  1. #21
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    Quote Originally Posted by roygoh
    The reason for the very low price is because this scope has been discontinued by Meade. It is the "RA" version, so it cannot be upgraded to electronic control (EC) and the AutoStar controller with Goto function.

    I have not used the RA motor for tracking before, as I have been mainly shooting the moon since I got the scope.
    If the RA motor can be used then it is a great price for a 90mm scope.

    How does the setup mounts onto your tripid? Does it allows for counterweight? Cos the weight of the setup in a polar alight fashion would probably put quite a bit of stress on the tripod.

    Sorry for so much question, but it really surprise me that a scope with a RA motor can be had at such a price.

  2. #22
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    Quote Originally Posted by frisky
    If the RA motor can be used then it is a great price for a 90mm scope.

    How does the setup mounts onto your tripid? Does it allows for counterweight? Cos the weight of the setup in a polar alight fashion would probably put quite a bit of stress on the tripod.

    Sorry for so much question, but it really surprise me that a scope with a RA motor can be had at such a price.
    The base plate of the telescope mount has a 4/20 hole so that it can be mounted directly onto a camera tripod. There are also 2 such holes on the base of the optical tube such that if you remove the tube from the mounting then it can be used like a spotting scope.

    There are special adapters that couples to the rear port of the tube such that the picture can be taken without reflecting on the internal diagonal mirror. I suppose that will gain some light because the mirror is slightly lossy.

    There are no features for attaching counter weights. Probably because the scope is already very small and light-weight.

    For polar alignment I believe my Benbo Trekker tripod would be very suitable as the center column itself can be tilted.

    Hope I answered your questions.

    Thanks!

    Roy
    As complexity rises, precise statements lose meaning and meaningful statements lose precision.

  3. #23
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    Quote Originally Posted by roygoh
    There are no features for attaching counter weights. Probably because the scope is already very small and light-weight.

    For polar alignment I believe my Benbo Trekker tripod would be very suitable as the center column itself can be tilted.
    Cool. Once you can tilt your center column, you can fashion some counter weight for it, if neccessary.

    Thanks.

  4. #24

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    Quote Originally Posted by roygoh
    By the way this is the setup:

    Wow!! Does anyone knows is there any shop that sell such a cheap n good setup?!!! Me very interested to get 1 but no idea how lei??
    anyone with this experience to share??
    Cheaper than a FL-40 flash man!!!

  5. #25
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    Ship it in lar. Hee hee

  6. #26

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    roygoh, can you post some of the mars pict you took with your setup?

  7. #27
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    Quote Originally Posted by ahbeng
    roygoh, can you post some of the mars pict you took with your setup?
    This scope does not have enough resolution for Mars. I tried anyway, and the results are no where near those taken by Starman. Anyway, here's one:


    CP995 + DCL28 + 3x Barlow + ETX90RA
    CP995 at maximum zoom, single exposure of 1/30 sec.
    As complexity rises, precise statements lose meaning and meaningful statements lose precision.

  8. #28

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    Whoa, this is nuts. Just a dumb question, but are you all "professors" when it comes to optics?? Cause all this formular and theory thing doesn't get into my head at all.. AHha..

  9. #29
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    Quote Originally Posted by roygoh
    CP995 + DCL28 + 3x Barlow + ETX90RA
    CP995 at maximum zoom, single exposure of 1/30 sec.
    turn off the 995 LCD and connect to a TV (yes...we were hardcore enough to drag the TV up the rooftop and bring extension cord there for power).

    I took a pic off the TV and here is how it looks like....


    Now you can ask all your friend to watch Mars together from the TV screen...more importantly, focusing is now much easier. For the CP4500 setting, we used ISO200, 1/30, f5.1, 4x optical zoom, couple to a 28mm eyepieces with 2x barlow. Also tried 3x barlow and 14mm eyepiece, but the end results not as good becos exceed the scope limit liao. Anyway, it is not the size, but the amount of details it can capture that matters.

    remember to set the white balance...never use auto! during focusing, we will zoom in all the way with digital zoom, to make sure that the object is focused before zoom back to 4x optical.

    btw, with the LCD off, it will generate less heat and thus less noise....also save power so that you can take hundreds of shots and do stacking....may be u can try putting dry ice around your 995?

    Try stacking a few hundreds shots...it will really do wonder and make a different, that's why some pple use cheap webcam because it can capture as video and then extract individual frame for stacking. However remember that the Mars is rotating...so you must finish a set of photo within 5 minutes
    Last edited by Wai; 30th August 2003 at 01:17 AM.

  10. #30
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    Quote Originally Posted by OzOn3
    Whoa, this is nuts. Just a dumb question, but are you all "professors" when it comes to optics?? Cause all this formular and theory thing doesn't get into my head at all.. AHha..
    I guess the problem here is that we are having a technical telescope discussion in a photographic forum. Despite being related in some way, it is a very niche area. Try having a technical discussion on, say batteries or CCD or something you are good at here, and I guess many of us won't have a clue......

  11. #31
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    In fact that's the next thing I am going to try. I will hook the video out from the CP995 to a USB video capture device (Dazzle 80) and then cature an AVI. Later I can stack the images to see if I can get a better image.

    Thanks for the tips on focusing!


    Quote Originally Posted by Wai
    turn off the 995 LCD and connect to a TV (yes...we were hardcore enough to drag the TV up the rooftop and bring extension cord there for power).

    I took a pic off the TV and here is how it looks like....


    Now you can ask all your friend to watch Mars together from the TV screen...more importantly, focusing is now much easier. For the CP4500 setting, we used ISO200, 1/30, f5.1, 4x optical zoom, couple to a 28mm eyepieces with 2x barlow. Also tried 3x barlow and 14mm eyepiece, but the end results not as good becos exceed the scope limit liao. Anyway, it is not the size, but the amount of details it can capture that matters.

    remember to set the white balance...never use auto! during focusing, we will zoom in all the way with digital zoom, to make sure that the object is focused before zoom back to 4x optical.

    btw, with the LCD off, it will generate less heat and thus less noise....also save power so that you can take hundreds of shots and do stacking....may be u can try putting dry ice around your 995?

    Try stacking a few hundreds shots...it will really do wonder and make a different, that's why some pple use cheap webcam because it can capture as video and then extract individual frame for stacking. However remember that the Mars is rotating...so you must finish a set of photo within 5 minutes
    As complexity rises, precise statements lose meaning and meaningful statements lose precision.

  12. #32
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    Quote Originally Posted by OzOn3
    Whoa, this is nuts. Just a dumb question, but are you all "professors" when it comes to optics?? Cause all this formular and theory thing doesn't get into my head at all.. AHha..
    I think not many of us here are formally trained in optics. I certainly do not. If you are interested enough, there is a lot of information you can find on the internet.
    As complexity rises, precise statements lose meaning and meaningful statements lose precision.

  13. #33
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    Quote Originally Posted by roygoh
    In fact that's the next thing I am going to try. I will hook the video out from the CP995 to a USB video capture device (Dazzle 80) and then cature an AVI. Later I can stack the images to see if I can get a better image.

    Thanks for the tips on focusing!
    hmm.....you may try but i think the quality come out of the TV-out may not be good enough, the resolution for TV is quite low

    my friend used to have a super sensitive CCD camera that can do "stacking" automatically, then it can be connected to the Hauppauge PVR USB using the composite IN or to a TV for viewing, a laptop can be used to store the video from USB PVR.

    however, practically not useful becos USB capture device is slow...and the laptop also too slow to process AVI smoothly, there will be lots of frame dropping and the hard disk space required is huge! even Hauppauge PVR got build in hardware Mpeg-1 and Mpeg-2 encoder, but it is still slow.

    More importantly, power source is not readily available (tot of buying a delicated power supply/generator but found that it is too expensive and not worth it). Laptop, TV, and the Video capture device all using different voltage (12V for telescope and video capture device, 20V for laptop) so need to pay more for a customised one....

    I think taking multiple pic to do stacking is the best...then take a dark frame after a few pic to subtract the noise manually (something like a D30)

  14. #34

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    Quote Originally Posted by Wai
    remember to set the white balance...never use auto! during focusing, we will zoom in all the way with digital zoom, to make sure that the object is focused before zoom back to 4x optical.

    about the white balance. talking in terms of canon s45, does that mean set the w/b to custom, then do w/b with the camera pointed at mars?

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