Can't get a star image

[hughejars]

BYE, V.3.1.18, Canon EOS 100D

I set up my trial version and used Venus as a test, nice and bright. Focused in great.

Waited til later in the evening and tried to Find some stars, I started with Vega brightest I could find. No matter how well lined up I was, or what ever settings I put camera to , I just could not get focus on any star. I tried using the FWHM, HFD etc, every ISO setting, every shutter speed, nothing but black skies.

Any hints or tips would be greatly appreciated.

[astroman133]

Use Maximum Sensitivity or manually set the exposure to 2 seconds and the ISO to maximum for LiveView focusing.

Even Vega will be tiny and barely visible because the LiveView exposure duration is only a few milliseconds long.

As an aside, when you set the exposure to 2 seconds, this does not mean that the camera is taking a 2 second image. The camera uses the selected exposure duration to determine how much to artificially brighten the image data.

If you are still unable to see the star in LiveView, then take a true 2 second Snap image. This should show you where to look in the LiveView image to find the star.

[s3igell]

Start by Focusing on the Moon or Venus, then lock the Focus (flip switch on Lens to Manual).

Now, aim at Vega or any Star or Cluster...  If Camera is allowed to attempt AutoFocus on a "Normal Star" then it will lose it...  The Camera Lens AutoFocus Routine is designed for Daytime Brightness and Contrast Levels.

[astroman133]

Yes, s3igell is correct. With a lens and its shorter focal length, the stars will be very small. You may need to use a snap image if you are trying to focus with a lens.

[hughejars]

Thanks, Yes I used Venus to set and lock my focus. But by the sounds of things, any light below about mag 1 is going to be challenging in live view.

[astroman133]

It is really not that difficult once you realize that what you are looking for is small and dim. It is easy to overlook. I have also found the "bright" star hiding behind the line of the border of the zoom box.

If you nudge the mount, with a hand controller, the star moving across the field of view will be easier to find.

But, yes you should only try to focus with LiveView on one of the brightest (top 20) stars in the sky.

[admin]

Keep in mind that live view is barely a few millisecond of data. In the dead of the night only the brightest stars will show up... and only if you are close to focus to begin with.