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Why is Saturn too Small with Video?

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#1 patindaytona

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Posted 22 September 2019 - 09:56 AM

I got my Canon adapter yesterday, tried it last night using my xt10 telescope.

I managed to be able to get Saturn in focus using a 12.5mm eye piece, but it's very very small in the LCD and also in the outcome video.

I thought maybe it's supposed to be and tried editing in Autostakkert, but i'd have to enlarge it way way too much for any decent resolution.

Does anyone know what's going on here? Thanks



#2 sg6

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Posted 22 September 2019 - 10:08 AM

In general all the plants are small, and Saturn is smaller then Jupiter and is further away.

In effect a 12.5mm eyepiece will not give a large magnification.

 

Guess about 90-95x

 

Even at nearest my best view was at 125x and even a small but clear Saturn.

 

Simple answer - accept what you have, maybe get another eyepiece for say 150x (8mm'ish). The other is wait until next July when it is clearer.

 

All enlarging will do is enlarge the lack of detail.

 

How was the video captured?



#3 zxx

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Posted 22 September 2019 - 10:15 AM

You really want a barlow to image the planets. 


Edited by zxx, 22 September 2019 - 10:31 AM.

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#4 FlankerOneTwo

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Posted 22 September 2019 - 10:33 AM

Planetary imaging is best done at long focal lengths ("magnification") and high frame rate (> 100 fps), because you will be very sensitive to atmospheric conditions at high power and will want lots of frames to select from in order to counteract that.

Rough rule of thumb is to shoot for around f/20; Jupiter on average will be one pixel per mm of aperture when close and Saturn is typically around half the diameter of Jupiter. And it's past opposition now, so it will be even smaller.

Your scope is 254mm, 1200mm focal length (f/4.7) so a 4x barlow should get you in the neighborhood for your typical Canon DSLR. I don't have any experience with Dobsonians, not sure how easy it will be to keep the planet in the field of view if you are manually tracking. 


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#5 patindaytona

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Posted 22 September 2019 - 12:01 PM

What i meant was that even though I'm using say a 12.5mm and it appears large to me, when i use same eye piece in the adapter for the video, it appears much much smaller instead.

Must be because of the smaller formatting of the single frames using a video vrs a still photograph with RAW.


Edited by patindaytona, 22 September 2019 - 12:02 PM.


#6 RedLionNJ

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Posted 22 September 2019 - 12:01 PM

Planetary imaging is best done at long focal lengths ("magnification") and high frame rate (> 100 fps), because you will be very sensitive to atmospheric conditions at high power and will want lots of frames to select from in order to counteract that.

Rough rule of thumb is to shoot for around f/20; Jupiter on average will be one pixel per mm of aperture when close and Saturn is typically around half the diameter of Jupiter. And it's past opposition now, so it will be even smaller.

Your scope is 254mm, 1200mm focal length (f/4.7) so a 4x barlow should get you in the neighborhood for your typical Canon DSLR. I don't have any experience with Dobsonians, not sure how easy it will be to keep the planet in the field of view if you are manually tracking. 

All this is perfectly correct - except for Saturn's diameter compared to Jupiter - they're a pretty similar size if you include the rings (which most people would).

 

You ought to be able to get close to 30fps with a Canon DSLR, tethered to BackyardEOS or similar.

 

But at the required focal length (around 5000mm), precise focusing and even keeping Saturn on the sensor is going to be troublesome.


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#7 beammeup

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Posted 22 September 2019 - 12:03 PM

3x barlow is what I use for 8 inch edge



#8 patindaytona

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Posted 22 September 2019 - 01:04 PM

Not sure if you understand what I mean about view in LCD on back of Camera, vrs the actual view thru same 12.5mm eye piece.

If i look thru it without any camera involved, planets etc appear much larger. But when i use same eye piece in my adapter using the camera for video, it's reduced in apparent size a huge amount.

I'm pretty sure it's because of the smaller frame size involved using video vrs a full rez. single still. But then, if I'm video taping it, it still should appear very large (same amount of magification as i would see the planet using the eye piece alone with no camera.


Edited by patindaytona, 22 September 2019 - 01:05 PM.


#9 Tulloch

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Posted 22 September 2019 - 09:46 PM

Not sure if you understand what I mean about view in LCD on back of Camera, vrs the actual view thru same 12.5mm eye piece.

If i look thru it without any camera involved, planets etc appear much larger. But when i use same eye piece in my adapter using the camera for video, it's reduced in apparent size a huge amount.

I'm pretty sure it's because of the smaller frame size involved using video vrs a full rez. single still. But then, if I'm video taping it, it still should appear very large (same amount of magification as i would see the planet using the eye piece alone with no camera.

Hi there, for best planetary imaging using a Canon DSLR, you need to be recording a 5x zoom of the "Live View" feed from the LCD sensor, not in video mode. If you do it right, the Canon DSLR setup can give you "almost" the same results as a dedicated planetary camera (such as a ZWO ASI224MC) if conditions are good to excellent. I myself have been imaging the planets with a Canon DSLR and Celestron Evolution 6" SCT with good results. I use the prime focus method (rather than eyepiece projection), but others like BQ Octantis use eyepiece projection.

 

https://www.cloudyni...6-sct-test-two/

https://www.cloudyni...sct-test-three/

 

You need to follow the instructions on this website and get yourself a program like BackyardEOS to record the Live View images to your computer.

http://www.astropix....resolution.html

 

Then you need to learn how to use the standard stacking and sharpening software packages for bringing out the best in your video feeds.

http://planetaryimagingtutorials.com/

 

There's a lot to learn, but the rewards can be great.

 

Hope this helps,

 

Andrew



#10 patindaytona

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Posted 22 September 2019 - 10:15 PM

Hi there, for best planetary imaging using a Canon DSLR, you need to be recording a 5x zoom of the "Live View" feed from the LCD sensor, not in video mode. If you do it right, the Canon DSLR setup can give you "almost" the same results as a dedicated planetary camera (such as a ZWO ASI224MC) if conditions are good to excellent. I myself have been imaging the planets with a Canon DSLR and Celestron Evolution 6" SCT with good results. I use the prime focus method (rather than eyepiece projection), but others like BQ Octantis use eyepiece projection.

 

https://www.cloudyni...6-sct-test-two/

https://www.cloudyni...sct-test-three/

 

You need to follow the instructions on this website and get yourself a program like BackyardEOS to record the Live View images to your computer.

http://www.astropix....resolution.html

 

Then you need to learn how to use the standard stacking and sharpening software packages for bringing out the best in your video feeds.

http://planetaryimagingtutorials.com/

 

There's a lot to learn, but the rewards can be great.

 

Hope this helps,

 

Andrew

Yes, I came across these things today. So, I would have to really need a laptop with me outdoors to do this, right?



#11 Tulloch

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Posted 23 September 2019 - 02:19 AM

Yes, I came across these things today. So, I would have to really need a laptop with me outdoors to do this, right?

Well, a computer of some sorts, yes. Laptops are certainly more portable, but there's no reason why you couldn't lug a desktop into the back yard...



#12 patindaytona

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Posted 23 September 2019 - 09:27 AM

Yes, I came across these things today. So, I would have to really need a laptop with me outdoors to do this, right?

 

Hi there, for best planetary imaging using a Canon DSLR, you need to be recording a 5x zoom of the "Live View" feed from the LCD sensor, not in video mode. If you do it right, the Canon DSLR setup can give you "almost" the same results as a dedicated planetary camera (such as a ZWO ASI224MC) if conditions are good to excellent. I myself have been imaging the planets with a Canon DSLR and Celestron Evolution 6" SCT with good results. I use the prime focus method (rather than eyepiece projection), but others like BQ Octantis use eyepiece projection.

 

https://www.cloudyni...6-sct-test-two/

https://www.cloudyni...sct-test-three/

 

You need to follow the instructions on this website and get yourself a program like BackyardEOS to record the Live View images to your computer.

http://www.astropix....resolution.html

 

Then you need to learn how to use the standard stacking and sharpening software packages for bringing out the best in your video feeds.

http://planetaryimagingtutorials.com/

 

There's a lot to learn, but the rewards can be great.

 

Hope this helps,

 

Andrew

Eventually, maybe I'd be better off buying a web cam instead. Not sure though. Either way, I'd have to bring a lap top computer outdoors. I'm so used to a desktop. I'd have to learn all over again to use a laptop with no mouse.  Is it real easy to use the software such as Astrophotography Tool?   I don't want to get into something way over my head..no pun intended.

Been watching an hour and so far the program wouldn't even apply to me since it's for long exposure still photos using a tracking device. Waiting....for the video stacking part.


Edited by patindaytona, 23 September 2019 - 11:03 AM.


#13 patindaytona

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Posted 23 September 2019 - 11:20 AM

Hi there, for best planetary imaging using a Canon DSLR, you need to be recording a 5x zoom of the "Live View" feed from the LCD sensor, not in video mode. If you do it right, the Canon DSLR setup can give you "almost" the same results as a dedicated planetary camera (such as a ZWO ASI224MC) if conditions are good to excellent. I myself have been imaging the planets with a Canon DSLR and Celestron Evolution 6" SCT with good results. I use the prime focus method (rather than eyepiece projection), but others like BQ Octantis use eyepiece projection.

 

https://www.cloudyni...6-sct-test-two/

https://www.cloudyni...sct-test-three/

 

You need to follow the instructions on this website and get yourself a program like BackyardEOS to record the Live View images to your computer.

http://www.astropix....resolution.html

 

Then you need to learn how to use the standard stacking and sharpening software packages for bringing out the best in your video feeds.

http://planetaryimagingtutorials.com/

 

There's a lot to learn, but the rewards can be great.

 

Hope this helps,

 

Andrew

"recording a 5x zoom of the "Live View" feed from the LCD sensor, not in video mode"

Not sure what you mean....Using Live View to take "still images" instead of video?

Saw something about the 5X zoom, but does that mean my actual output result will be 5X larger also? Or just on the laptop screen?

As it is right now, weather i use my barlow, or a high mag. eye piece, what i see on video is always the same very very small size image (video of saturn).  Seems like i get no magnification at all...or barely.



#14 patindaytona

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Posted 23 September 2019 - 11:22 AM

In general all the plants are small, and Saturn is smaller then Jupiter and is further away.

In effect a 12.5mm eyepiece will not give a large magnification.

 

Guess about 90-95x

 

Even at nearest my best view was at 125x and even a small but clear Saturn.

 

Simple answer - accept what you have, maybe get another eyepiece for say 150x (8mm'ish). The other is wait until next July when it is clearer.

 

All enlarging will do is enlarge the lack of detail.

 

How was the video captured?

What I am saying is that I get the magnifications I'm after when using my eye pieces, but when I use those same eye pieces in my adapter for the camera and take a video (for stacking later on), the images are very very small. Saturn is no longer that big image I got when using that eye piece directly into my scope with no adapter (and no video process).



#15 Tulloch

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Posted 23 September 2019 - 05:23 PM

"recording a 5x zoom of the "Live View" feed from the LCD sensor, not in video mode"

Not sure what you mean....Using Live View to take "still images" instead of video?

Saw something about the 5X zoom, but does that mean my actual output result will be 5X larger also? Or just on the laptop screen?

As it is right now, weather i use my barlow, or a high mag. eye piece, what i see on video is always the same very very small size image (video of saturn).  Seems like i get no magnification at all...or barely.

In Backyard EOS there are two ways to record the Live View - a series of jpgs (I usually record 10,000 in 4 loops of 2500) or as an avi file, which is really just the jpg files combined to make the avi. There is no difference in quality, the avi is just a "bag" to hold all the jpgs in.

 

5x Live View is a simply a cropped section of the camera's sensor, so that only the central 1120 x 752 pixels are shown and recorded. The advantage with this method is that there is no interpolation so the result is as close to raw pixel output as you can get from a DSLR. The Canon does perform some noise reduction on the recorded images which helps process the data later.

 

As I said in my other reply, the reduced pixel size is all you need to get a great result. The standard ZWO planetary camera (the ASI224MC) is only about 1 Mpixel in resolution, which is very similar to the Canon. 

https://www.cloudyni...-two/?p=9663314

 

Andrew




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