LENR Canon Ra

[whensche]

How does the software handle the LENR noise setting of the canon Ra?  The camera will take the initial image and then automatically take a dark image. Alan Dyer claims in camera noise reduction is the way to go. However, the Backyard EOS only allow an image of a specified length and then immediately downloads... before the camera dark image can be take. This is important for foreground pictures to eliminate noise. Do we have to take "Light" and "dark" separate images of the same scene... or ... is there a way to let Backyard EOS know that LENR is turned on in the camera. I don't even know if it makes a difference. Thanks

Grand Marais, MN USA

[astroman133]

Dark frames are NOT "of the same scene" as light frames.. Dark frames are ideally taken with no ambient light reaching the sensor so where the camera is aimed is of no consequence. Only the sensor temperature, exposure, ISO, and that no ambient light reaches the sensor are of any importance.

Based on my testing, BYE's behavior is NOT as you state when you say that "Backyard EOS only allow an image of a specified length and then immediately downloads".

BYE only downloads an image when the camera says that the image is ready to be downloaded. I turned on LENR on my T5i from the in-camera menus and used BYE 3.2.0 - RC4 to shoot images of different lengths (10 seconds, 1 minute, and 5 minute). In each case BYE patiently waited while he T5i shot and applied the in-camera dark frame, and only then downloaded the resulting image. It may be that at some point BYE times out and says that no image was available, but it did not occur with a 5 minute exposure.

I don't know what would happen if you tried to take a 20 minute Ha image with LENR turned on. You should download the free 30-day trial of BYE and try it yourself, at the kitchen table, during the day, with the lens cap on the camera.

Personally, I would prefer to capture twice as many light frames rather than use LENR, but I have no data to support my conclusion. However, my testing shows that BYE is programmed that LENR may be used and is tolerant of that.

[whensche]

Thanks alot for very useful information. I have used BYE several years  but am just now trying LENR with my new canon Ra camera. Good forum... fast results. Thanks all

[dkerber]

Most astrophotographers recommend taking twice as many  lights, and then applying 10 or 20 darks during processing, rather than using LENR, but I don't know if anybody has done a scientifically rigorous comparison to see how the results compare.

[admin]

Alan Dyer, although well respected, is wrong.  You do not want to waste precious dark time taking darks.  

Take as much light frames as your can during the night and use/build a dark library that you can re-use time and time again some other time.... a cloudy night is the perfect time to take dark frames.