Resolution Limits for AVI Video

[MichaelAdler]

I am new to Backyard EOS. I have a Canon 5D Mk4 and want to do make an AVI video in the Planetary mode at the full resolution of the chip and uncropped. I did a 5x zoom in BYEOS and got a video at the full res but only for the center 20% of the chip, eg heavily cropped. When I make a video for the whole sensor the resolution is only 960x640. Is there a way to make a video at higher res and for a larger portion of the chip. I assume this would have to be at a lower frame rate.

[astroman133]

Michael,

The short answer to your question is, sadly, no. It is not possible to use BYE's Planetary mode to collect images at the full resolution of the sensor AND uncropped. The best that you can do is to use the 5X zoom, which gives the full resolution of the sensor but only for the central portion if the image. This is because BYE uses the downloaded LiveView frames to compile into the AVI video. LiveView frames are sized to fit on the LCD display of the camera which is roughly 1/5th the size of the full sensor.

For planetary imaging the 5X zoom mode is fine, even at long focal lengths for Mars, Jupiter, and Saturn. What are you trying to image? the Moon? If the Moon, then you can use 5X Zoom Planetary mode and create a mosaic. I did this a few years ago. I used RegiStax to create a single image from each each video for one panel of the mosaic and then used RegiStar to combine the panels into a single image. I was happy with the result.

You can also shoot short still frames, say at 1/500th second and ISO 800. This could be done at the full sensor resolution. I have never tried it, but you might be able to use RegiStax to grade each of the images to allow you to take the best one.

[s3igell]

While a lot of Beginners believe that "Full Resolution" will make their Planetary Video "BETTER", that is not actually the case.  First, it will simply give you a much wider Field-of-View - and make the Planet you are shooting seem even so much SMALLER.  Second, It is the Higher Frame-Rate coupled with a near 1:1 Pixel Resolution that gets you the best Planetary Stacking for Resolution and Detail.

For additional explanation, look at one of my older posts on the topic:  

Or, to get a "Bigger Picture", simply "Search" this Forum for "FULLHD".

 

[MichaelAdler]

Thanks all for your prompt response to my question. I should have added that indeed I am looking to image the sun and the moon and I do realize that the 5x zoom will be perfect for the planets. The most immediate application will be the solar eclipse. I am using a Daystar hydrogen alpha filter with a 4x barlow with a telescope with 480mm focal length. The field of view using the Canon 5D Mk4 body  will be 0.9x1.4 degrees. If I crop using the 5x I will not be able to capture the whole sun. I guess the best I can do when tethered to my  laptop is to get the 1920x1080 video signal output. The other thing I could do is to mount the camera piggy back on the tracking telescope and use a 100mm canon lens. Then the 5x zoom will allow me to see the whole sun.

Mike Adler

[astroman133]

I am planning on using my DSLR attached to a 5" refractor with a white light filter over the objective and a focal reducer in front of the camera. This will give me 1) about a 3 degree FOV, 2) the ability to remove the filter to image at totality, 3) the ability to catch most of the outer corona at totality.

I will be shooting a variety of single exposures with durations varying from 1/4000th of a second up to 2 seconds. In my opinion, things happen too quickly during the eclipse to try to shoot with a hydrogen alpha filter or scope, especially with a DSLR where only 25% of the pixels will even see any signal through the filter.

Good luck, Mike.

[MichaelAdler]

Rick, thanks for your input here. I thought I would elaborate a bit as some of my approach may be useful to you. During totality I will use my Takahashi FS152 with a f5.6 focal reducer and the  Astro Photography Tool to control my Canon 5D Mk4. I found that if I put the camera in exposure bracketing +- 3 stops and a 1 sec pause between each bracket set I can get exposures over a very broad range say from 1/4000, 1/500, 1/60 at 7 fps. I will change the center exposure throughout the totality.  Even though APT is not supposed to be able to support bracketing, it does work with 3 exposures as long as there is a 1 second pause between. I plan on having the whole sequence programed ahead of time for the whole 2minute + of totality.

Before and after totality I will use my Takahashi FSQ 85 which is my finder scope on the FS152 with the Daystar H alpha filter. This filter will provide detail in prominances as well as surface detail. I have a Canon 5D Mk3 which has been modified for improved IR sensitivity. The reason for the video is to do some stacking to get better resolution and I think that the 1080p resolution should be OK but I will experiment before the eclipse to see how this works. The other option is to take a bunch of still images as you suggested. After the eclipse, the 5x setting on BYEOS will be fine as I will want to be taking higher magnifications.

BTW, I am located in Jackson Hole. Where are you located?

Mike Adler

[astroman133]

Mike,

I live in "Heat Central"...southeastern Arizona at 4400 ft. elevation, and currently at 112 degrees and 11% humidity, but I will be traveling to Casper, WY for the Astronomical League Convention and the eclipse.

I will be shooting the eclipse through a StellarVue 130 and T5i. My eclipse capture plan will be controlled by Eclipse Orchestrator. I currently have EO set to shoot over 100 exposures from before 1st contact to after 4th contact. During totality, the exposure plan is so busy that I gave up on trying exposure bracketing because it means disconnecting the camera to enable and disable bracketing during the event. The exposures are all at ISO 100 and vary in duration from 1/4000 to 2 seconds.

I also plan to shoot a terrestrial video with a GoPro 5 on a tripod during totality. I have limited space for the trip so I will only be taking a single telescope, which I plan to use for nighttime work, as well.

I may also shoot a nighttime time lapse with the T5i on a Vixen Polarie to pan at sidereal rate while visiting Glacier National Park before the convention.

Thanks for sharing your plans.