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Reaching Binocular focus

Posted in Astrophotography with tags , , , , , , on 2009/09/29 by computerphysicslab

Someone asked me for help recently using this comment:

“Hello, I have 16×50 binoculars and a 7.1 mega pixel camera with 4x zoom and I’ve done what you said and looked at the Moon and the images are no where near as close as yours. The image blurs once the picture is taken of the moon and doesn’t seem no where near as close to the moon as yours. Please help.”

I would like to share the answer just in case someone is also interested.

Answer:

16x and 4x should mean a final 64x optical zoom. That is as much as when seeing through a telescope. If you are capturing frames at 7 MegaPixels this is to say they are around 3,000×2,500 pixels in size. When creating a video you need a final image size of 1,000×700 as much, so if you crop a frame of 3,000×2,500 into a final frame of 1,000×700, it would be equivalent to apply a 3x additional zoom to the image, because (1,000×700) * 3 is more o less equal to 3,000×2,500.

Bottom line: do a crop to your 7 Mpx image and you will get an effective 182x magnification.

Respecting the blur, don’t panic. The blur may be a product of the weather conditions, or a thermal issue in your binoculars.

Try to avoid make photos of the Moon when it is located directly over the roof of a neighbour. This is a very frequent source of blurring problems.

Try also to cool down your binoculars before the observation, trying to get a thermal equilibrium with the outdoor temperature.

Be sure that your digicam is functioning with a infinite focus mode. The focus must be achieved manually using the binocular focuser.

If you have the option of taking continuous shots, use it. The majority of the images recorded may be blurred, but sometimes you may get one more clear and sharp.

Well. I hope this helps you to get sharper images.

Good luck.

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