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Saturn with Dobsonian

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#1 patindaytona

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Posted 22 September 2019 - 11:52 PM

finished SATURN cRopped  jgg.jpg

My first attempt to process a planet.

Used my Canon DSLR on dobsonian.

Combined two short videos and processed to avi with PIPP, then Autostakkert, then Registat and some LIghtroom and Photoshop.

I like to use the High Pass Filter in photoshop because it sharpens just the edges only.


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#2 zxx

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Posted 23 September 2019 - 11:27 AM

Need to cover more pixels, looks like about 80 pixels cover the planet end to end so processing will be limited. 

Need a barlow , My Z12 at 4500mm will cover about 300 pixels on Saturn end to end with the ASI120mc.

 

Nice first attempt with a DSLR on a Dob.


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#3 patindaytona

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Posted 23 September 2019 - 11:34 AM

Need to cover more pixels, looks like about 80 pixels cover the planet end to end so processing will be limited. 

Need a barlow , My Z12 at 4500mm will cover about 300 pixels on Saturn end to end with the ASI120mc.

 

Nice first attempt with a DSLR on a Dob.

Basically you're saying it's not in the processing, but in the resolution of when the image was taken?

I still can't figure out why my images are so small on my videos. I used a barlow, i tried using a 10mm eye piece also. The resulting video magnification of the planet is always the same...very small.

Using the 5X 1:1 in a program such as Backyard EOS, will it give me the magnification I'm after? I mean on video.



#4 zxx

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Posted 23 September 2019 - 11:42 AM

Basically you're saying it's not in the processing, but in the resolution of when the image was taken?

I still can't figure out why my images are so small on my videos. I used a barlow, i tried using a 10mm eye piece also. The resulting video magnification of the planet is always the same...very small.

Using the 5X 1:1 in a program such as Backyard EOS, will it give me the magnification I'm after? I mean on video.

I never tried it with my DSLR, is it a FF camera , What x barlow ? I'm guessing the image was cropped ?


Edited by zxx, 23 September 2019 - 11:45 AM.


#5 patindaytona

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Posted 23 September 2019 - 11:44 AM

I never tried it with my DSLR, is it a FF camera , What x barlow ?

Canon 5D Mark II full frame

2X Barlow

Once my adapter is fitted the image size goes way way down from what i had looking thru with without the adapter on.



#6 zxx

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Posted 23 September 2019 - 11:51 AM

Canon 5D Mark II full frame

2X Barlow

Once my adapter is fitted the image size goes way way down from what i had looking thru with without the adapter on.

You can put an extension into the barlow and get more FL. The further away the camera is from the barlow the more FL you will get. I used a 2" 2x barlow with a 1.25 x 5" extension with my ASI120mc


Edited by zxx, 23 September 2019 - 12:02 PM.


#7 Stephen Kennedy

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Posted 23 September 2019 - 02:06 PM

Although they appear bright to the naked eye, planets are really very small compared to most DSOs.  Saturn is only about 25 arc seconds compared to the many arc minutes that we typically see with DSOs.  My Newtonian has an aperture of 210 mm and a focal length of 1,623 mm but even at 100X visually it is very small,  I have to go to 235X with my Pentax XW 7 eyepiece before I get an image large enough to really start seeing detail.  While imaging DSOs we normally use prime focus which works well on objects that are 20 arc minutes in size.

 

I have had my best results imaging planets using eyepiece projection which I realize is generally advised against.  It can work with right equipment and sometimes a little trial and error,  You need to take an Avi video which can be processed using Registax software to remove the effects of the atmosphere.  You need an adapter that is specifically designed for eyepiece projection which is available from High Point Scientific at a reasonable price.  Well corrected eyepieces are crucial.  The Pentax XW 7 and similar eyepieces from Tele Vue will not fit in the adapter and can not be used.  I use old Vixen orthoscopics of either 12 mm or 18 mm focal length,  When ever you put a refracting element in the optical train there is the risk of chromatic aberation but good quality eyepieces like the Vixens minimize this risk, particularly if you are using an all mirror telescope like a Newtonian or RC.

 

I have always used a tracking GEM which makes image acquisition much easier but I suppose it can be done with a Dobsonian with a large aperture, particularly if it has some kind of powered alt-az tracking capability,  The OP's image of Saturn is very good one obtained with a non-tracking  mount.

 

This is an image I obtained several years ago of Saturn using an eyepiece.

 

https://astrob.in/240715/0/


Edited by Stephen Kennedy, 23 September 2019 - 02:13 PM.

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#8 patindaytona

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Posted 23 September 2019 - 02:20 PM

Although they appear bright to the naked eye, planets are really very small compared to most DSOs.  Saturn is only about 25 arc seconds compared to the many arc minutes that we typically see with DSOs.  My Newtonian has an aperture of 210 mm and a focal length of 1,623 mm but even at 100X visually it is very small,  I have to go to 235X with my Pentax XW 7 eyepiece before I get an image large enough to really start seeing detail.  While imaging DSOs we normally use prime focus which works well on objects that are 20 arc minutes in size.

 

I have had my best results imaging planets using eyepiece projection which I realize is generally advised against.  It can work with right equipment and sometimes a little trial and error,  You need to take an Avi video which can be processed using Registax software to remove the effects of the atmosphere.  You need an adapter that is specifically designed for eyepiece projection which is available from High Point Scientific at a reasonable price.  Well corrected eyepieces are crucial.  The Pentax XW 7 and similar eyepieces from Tele Vue will not fit in the adapter and can not be used.  I use old Vixen orthoscopics of either 12 mm or 18 mm focal length,  When ever you put a refracting element in the optical train there is the risk of chromatic aberation but good quality eyepieces like the Vixens minimize this risk, particularly if you are using an all mirror telescope like a Newtonian or RC.

 

I have always used a tracking GEM which makes image acquisition much easier but I suppose it can be done with a Dobsonian with a large aperture, particularly if it has some kind of powered alt-az tracking capability,  The OP's image of Saturn is very good one obtained with a non-tracking  mount.

 

This is an image I obtained several years ago of Saturn using an eyepiece.

 

https://astrob.in/240715/0/

I understand that. My question is that i do not get equal magnification that i get using the very same eye piece. Two different results.

Saturn for example is BIG in my eye piece.

But when i put that particular eye piece into my camera adapter to take a video, it is NOT big anymore. It's reduced in size ALOT.

I see Saturn on my LCD and it's not much more than a small starlike image drifting across the LCD.

I do not know why that is happening.

I sure would like to know.

I am thinking it's because i need software to increase it to the 1:1 pixel resolution. That would I am hoping...increase the size (magification) of my image (the final result).




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