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ProcyonOne

Mars and Jupiter - just white circles - how to correct planetary exposure?

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Hi,

 

 This was my second attempt at capturing images with my T3i and Backyard EOS. My first attempt with the Sun was successful.  Tonight I tried to capture images of Mars and Jupiter.  I connected a T-Adapter to my camera and connected that directly to my SCT.  No other optics besides the camera and the scope.  When trying to focus I did not notice any detail in the white dot that I saw in the program.  Then I went into planetary mode and captured 1000 movie frames set as ISO 100 and 5X mode.  I had the camera set on "M". What did I end up with - nothing but a white circle :-(  Nothing usable.

 

 Now it's pretty obvious to me that I overexposed the image.  Can anyone please give me a suggestion on how to get this set up properly? Should I be using eyepiece projection instead? How can I darken the image so it's not overexposed in the planetary movie mode?   This is all new to me, have been observing for years but never tried photography before.

 

 Many thanks - want to try to get Mars while I still can!

 

 

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Focus is critical.  Use BYE Frame and Focus to focus on a bright star near your target. Then slew to your planet.  BYE's Planetary mode uses captured LiveView frames to assemble a video (.avi) file.  LiveView downloads frames at around 15 per second so the exposure is fixed to be something less than that and is not user-controlled.  Canon allows you to use both the ISO and exposure duration settings to control the brightness of the LiveView image. So, set your ISO to 400 or 800 and then shorten the exposure value to darken the display until you can see Jupiter's equatorial bands. I cannot suggest values because your setup will require different values from mine.

 

Until you gain experience with the technique, I would suggest that after you have captured your first video, that you capture 2 more using a shorter and a longer exposure so you can decide what looks best.  I would also say that, within reason, being under exposed is better than being overexposed.

 

Another point is that for some cameras you may have to change a setting in the camera's menus to allow "Live View Exposure Simulation".  So if you are not able to darken the LiveView image by adjusting the exposure, go look for that setting in the camera and enable it.

 

Good Luck,

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Live view exposure simulation is not active when in BULB mode.  Not a lot of people know that... so... make sure you select a TV value < 2" and you will see a difference.  Especially when you get down to the sub seconds TV values.

 

So in planetary...

1) always set the dial to M

2) always select a TV value, never BULB

3) always select 5x zoom (unless you are imaging the moon and you want the full disk)

 

Hope this help.

 

Guylain

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One of the issues with Planetary Imaging that results in "white circles" is Over-Exposure.

 

While the Nighttime Sky is rather Dark, one needs to remember that the Planets are Brightly Lit by Reflected Sunlight - especially the Planets which are the usual targets of DSLR-based Imaging.

You'll actually need to manage your Shutterspeed downwards to reduce the Exposure - Mars and Jupiter may need Tv of 1/120 or 1/160 or even quicker depending on your Scope.

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Planetary Imaging is usually pursued with the Longest Focal Length Scope that you have access.  This will often be an SCT or a Refractor (sometimes a cheap Achromat), rather than the "Quick" Newtonians and Widefield APO Refractors favored for DSO Imaging.  Almost all Planetary Imaging is done Prime Focus.

Some of the best pictures are captured on large C14 and Meade 16in SCT, because of their exceedingly Long Focal Length (often augmented by a 2x Barlow) that gives the Planet "size" as well as the large Aperture that gives the Image its fine detail.

Usually, Aperture is equated with capturing sufficient Light for an Object, but as the Planets are inherently Bright that is not as much a concern.  Basic Planetary Imaging can be done with Smaller Aperture but Longer Focal Length Scopes - those F/10 Achromat Refractors of 60mm / 70mm that are too often sold as "Beginners Scopes" are usually good enough for this Planetary Imaging purpose.  Also, adding a 2x Barlow is usually successful - again no issue with too little light.

 

The biggest consideration beyond Focal Length is:  Planetary Video Capture vs Single Shots.  Use the BYE Planetary mode to capture 5x LiveView Data.  This is the easiest entry-point to Video Image Stacking (Lucky Imaging), which is the gateway to improved Planetary Images.

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s3igell

 

Thanks for the detailed explanation. this will bring up another question will eyepiece projection work with my newt. for planetary imaging? or should I just invest in a inexpensive refractor. would my short tube 80 work in the interim.

 

 

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Try both Afocal and Eyepiece Projection - either or both may work for you.

 

It's unlikely that you'll get even as goo results with the ST-80 as with the AT8IN - the ST-80 is even Shorter Focal Length (400mm vs 800mm).

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s3igell

 

Thanks again. Ill give those two techniques a try. Ill need to get a about a 10mm eyepiece and maybe a Barlow for Eyepiece projection. but that is way cheaper than a scope.

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Hi, sorry to butt in here, but I am new to BYEOS and this forum and cannot figure out how to post a new topic. There also seems to be no one else to turn too. I am trying to do planetary with aT3i but cannot connect to the camera.

 

I am running my observatory off an off-line XP laptop. Prefer to keep it ofline for security and dont't want to change OS. BYEOS does't detect my T3i. Thought I might need drivers, but Canon website says there are no T3i drivers for XP. Can anyone help?

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There is a "New Topic" button at the Upper-Right of every Forum (not Thread) Page.

 

Start a new Thread (so as to not Hijack this one), and you will likely get rather quick response with answers to your questions...

 

 

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To start a new topic: From the Forums page, select the forum, for example BackyardEOS. Then select New Topic above the header bar on the right hand side of the window.

 

XP should automatically recognize your camera.  This must happen before BYE will be able to connect with it.  After plugging the USB cable to a both the camera and the PC and powering the camera on, you should see the camera in the list of devices in the Windows Device manager. If this does not happen, then there is some problem with XP.

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