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Thread: Astrophotography

  1. Top | #11
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    Quote Originally Posted by Jimmy Higgins View Post
    This is on the to-do list. We (8-yo daughter and I) recently got an 8-inch'er with EQ mount. She is really into it. The tracking mount makes things so much easier to keep an 8-yo's head in the game. Finally got Jupiter done, early morning thing, and my daughter leapt out of bed when I told her the scope was targeted on it. So she has seen Mars (crappy underwater quality, but big), Jupiter (washed out, turn good), Saturn (pretty good), and Uranus. We had gotten the scope just before the conjunction (took two months to get!), but it was cloudy skies for literally one month straight!

    Need to get the adapter to get the camera on it. I think I also need to get a north star tool for alignment. I think our equipment, including camera (Sony, which is good with low light) is the minimum required, so the shots should be adequate, nothing great. My Uncle is a "pro", well, "pro-amateur". He did this stuff back in the 80s when you really needed to know your stuff. He now how a pole mounted into the ground for a "tripod", and can take ridiculously long exposures, half-hour plus! He was sent me some mind blowing stuff.
    Polar alignment is essential for good tracking. It takes me a good hour to get a proper alignment. Often have to redo it several times. Get a good guidescope and a guide camera. Then you need PhD guiding, which is a free software. Once you have that up and running you can 3 minute shots. No more than that usually. Don’t forget darks, flats and bias shots. Still need a better way to do flats. I’m missing them above and it shows.

    You can do planetary imaging without it.

  2. Top | #12
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    Looked it up, and apparently the mount I have actually has a place for a polar alignment scope, it is well hidden. So I order that up, a t-mount adapter, and a bulb clicker for the camera, etc... and will see how this works out. With that bulb clicker (for whatever reason Sony made the older one obsolete), I'm going to need to do some waterfall stuff with the ND filter.

    But astro first, it'll be tricky with leaves. Out. Hopefully the Sisters are farther along their path and clear. I think the Orion Nebula is blocked for a while. I'll need to check the moon rising and setting.

  3. Top | #13
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    Quote Originally Posted by Jimmy Higgins View Post
    Looked it up, and apparently the mount I have actually has a place for a polar alignment scope, it is well hidden. So I order that up, a t-mount adapter, and a bulb clicker for the camera, etc... and will see how this works out. With that bulb clicker (for whatever reason Sony made the older one obsolete), I'm going to need to do some waterfall stuff with the ND filter.

    But astro first, it'll be tricky with leaves. Out. Hopefully the Sisters are farther along their path and clear. I think the Orion Nebula is blocked for a while. I'll need to check the moon rising and setting.
    There’s plenty of good apps for planning. I like Orion sky safari, but it’s about $16. Stellarium is free and also great. There’s also a free polar alignment app that I find helpful.

    Orion is great for photography because it’s so bright. You only need 30 second shots of it to get a good overall photo. More than that and you blow out the trapezium. But it won’t be back until the fall. But summer Galaxy shots are great. There are lots of bright nebulas you can capture. M20, M8, M16. To go beyond 30 seconds you’ll need a guidescope and guide camera. Used ones are easily found and fairly cheap. Mine were actually free, given to me by others who were upgrading. Download PhD guiding as it’s a free app. Also download ImagesPlus a free Astrophotography software. You’ll need to watch a YouTube video about it first to understand what to do. But it’s a real good processing program specifically designed for Astrophotography.

    The moon’s up for the next couple of weeks, but contact me off line when you’re going up and I’d be happy to help. And here’s my Orion done about a year and a half ago.


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    That is incredible.

    Received the stuff yesterday. Had to go out and get a metric set of hex wrenches. *YAK!* (Thank goodness I had a Hex wrench < 1/16", otherwise I would have got that first... and then realized I needed metric). But the polar scope is aligned with the mount.

    T-mount adapter fits the camera. So seem to have the pieces. We'll see how things are tonight. Start with the moon.

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    Here is a question, is film better than digital? IE, it is possible to use a film camera and stack photos onto a single frame, without using any computers. I get that noise can become an issue, but if you stack short frames, does that mitigate that problem? Obviously, this would be for Deep Space stuff. I'm not clear on when noise becomes a problem, ie, whether it is simply an aggregate thing or a length of exposure thing.

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    Quote Originally Posted by Jimmy Higgins View Post
    Here is a question, is film better than digital? IE, it is possible to use a film camera and stack photos onto a single frame, without using any computers. I get that noise can become an issue, but if you stack short frames, does that mitigate that problem? Obviously, this would be for Deep Space stuff. I'm not clear on when noise becomes a problem, ie, whether it is simply an aggregate thing or a length of exposure thing.
    All professional astronomy is done with digital detectors now so I don’t feel that film could be superior. I’m not sure how you’d stack film photographs.

    Noise comes in a few flavors, but if the noise is random then stacking more images will help. If it is systematic noise then it won’t help. Longer exposures may be preferred when read noise is high, but shorter exposures can help in other ways.

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    Quote Originally Posted by Shadowy Man View Post
    Quote Originally Posted by Jimmy Higgins View Post
    Here is a question, is film better than digital? IE, it is possible to use a film camera and stack photos onto a single frame, without using any computers. I get that noise can become an issue, but if you stack short frames, does that mitigate that problem? Obviously, this would be for Deep Space stuff. I'm not clear on when noise becomes a problem, ie, whether it is simply an aggregate thing or a length of exposure thing.
    All professional astronomy is done with digital detectors now so I don’t feel that film could be superior. I’m not sure how you’d stack film photographs.
    Some film cameras allow you to not advance the film, so you can take multiple images on a single frame. For normal photography, you could take 4 shots of a length that is 1/4th that required for a proper exposure so the aggregate length is still the same. I did this to get a ghost effect of people on a boardwalk.



    Noise comes in a few flavors, but if the noise is random then stacking more images will help. If it is systematic noise then it won’t help. Longer exposures may be preferred when read noise is high, but shorter exposures can help in other ways.
    I figure people aren't stacking for the fun of it and it makes things work better.

  8. Top | #18
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    Quote Originally Posted by Jimmy Higgins View Post
    Here is a question, is film better than digital? IE, it is possible to use a film camera and stack photos onto a single frame, without using any computers. I get that noise can become an issue, but if you stack short frames, does that mitigate that problem? Obviously, this would be for Deep Space stuff. I'm not clear on when noise becomes a problem, ie, whether it is simply an aggregate thing or a length of exposure thing.
    Quote Originally Posted by Jimmy Higgins View Post
    Some film cameras allow you to not advance the film, so you can take multiple images on a single frame. For normal photography, you could take 4 shots of a length that is 1/4th that required for a proper exposure so the aggregate length is still the same. I did this to get a ghost effect of people on a boardwalk.



    Noise comes in a few flavors, but if the noise is random then stacking more images will help. If it is systematic noise then it won’t help. Longer exposures may be preferred when read noise is high, but shorter exposures can help in other ways.
    I figure people aren't stacking for the fun of it and it makes things work better.
    Stacking is used to help eliminate noise and to avoid having to track the stars. Multi-exposing film would get rid of both of these benefits. If you are using film mount your camera on a mount that tracks and simply leave the shutter open as long as your exposure calls for.

  9. Top | #19
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    Quote Originally Posted by Jimmy Higgins View Post
    Some film cameras allow you to not advance the film, so you can take multiple images on a single frame. For normal photography, you could take 4 shots of a length that is 1/4th that required for a proper exposure so the aggregate length is still the same. I did this to get a ghost effect of people on a boardwalk.
    Sure, but since you’re still using the same piece of film you haven’t gained anything in terms of dynamic range. So, how would this be any different than a long exposure? I guess if you’re not tracking an astronomical object and you need to adjust pointing so as to not smear out an image as a longer exposure would do. But if you are interested in deep space photography that requires long exposures you better be tracking.

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    I could be completely wrong but I thought that one of the points to stacking multiple images was that real objects like star will be consistent but noise totally random and so easy to filter out in processing.

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