Astro-photography shutter speed no tracking

[JBW]

It's been said that astro-photography is the most complex genre in photography. I wouldn't bet my eternal soul that it is. But if it isn't I don't want to try what is.

Last night I experimented with shutter speed. To be precise the difference between one second and four seconds using my Tamron 90mm 272E attached to a Sony Alpha a58. Did I mention the complexity of astro-photography? This test is only valid for this camera and this lens.

The first shot is Saturn at 1 s. Not so good. The second is Antares, M4 (the faint fuzzy) and the Oph Nebula (look for Mickey Mouse in the top half of the shot). Both shots have identical post processing, including stacking in DSS. They were taken within two minutes of each other.

I'll be going with a four second shutter speed.





Brian

[george013]

It's been said that astro-photography is the most complex genre in photography. I wouldn't bet my eternal soul that it is. But if it isn't I don't want to try what is.

Last night I experimented with shutter speed. To be precise the difference between one second and four seconds using my Tamron 90mm 272E attached to a Sony Alpha a58. Did I mention the complexity of astro-photography? This test is only valid for this camera and this lens.

The first shot is Saturn at 1 s. Not so good. The second is Antares, M4 (the faint fuzzy) and the Oph Nebula (look for Mickey Mouse in the top half of the shot). Both shots have identical post processing, including stacking in DSS. They were taken within two minutes of each other.

I'll be going with a four second shutter speed.


Brian

I don't know much about the sky but I see the same big stars in both shots, only a little bit turned. And a lot more in the second one.
From what I've read about the shutter speed is that it will be a balance between noice and trails. Not so long ago somebody here mentioned the speed of the moon as a factor of it's size on the sensor.
What do you mean with "stacking in DSS". Did you take more pictures?

George

[JBW]

I don't know much about the sky but I see the same big stars in both shots, only a little bit turned. And a lot more in the second one.
From what I've read about the shutter speed is that it will be a balance between noice and trails. Not so long ago somebody here mentioned the speed of the moon as a factor of it's size on the sensor.
What do you mean with "stacking in DSS". Did you take more pictures?

George

Actually you don't as stated the first shot is of Saturn. The second shot is Antares, M4 and the Oph Nebula.

As I understand it shutter speed is all about how many photons are collected. The longer it stays open the more you collect. Sadly after a certain amount of time an open shutter that is not attached to a camera that is attached to a tracking mount is going to show star trails.

DSS is a program designed as a deep space astro-photography stacker and limited editor.

[george013]

Actually you don't as stated the first shot is of Saturn. The second shot is Antares, M4 and the Oph Nebula.

As I understand it shutter speed is all about how many photons are collected. The longer it stays open the more you collect. Sadly after a certain amount of time an open shutter that is not attached to a camera that is attached to a tracking mount is going to show star trails.

DSS is a program designed as a deep space astro-photography stacker and limited editor.

Dave corrected your post of the second image. Now I can see it clear.

It's not only collecting photons. There's also a load over the sensor that heathens it. The longer it's used, the warmer it gets the more noise it will produce. This is camera dependent.

If you want to know, there's a program Deadpixeltest. The idea behind this program is that you make a picture with the lens cap on. So completely dark. The program checks this picture on non-black pixels. You can make use of a threshold for the noise. You can play with different exposures and isso settings. Maybe you find out that your camera doesn't create much more pixels with some higher isso. So not why use that. It are just thoughts.
http://www.photo-freeware.net/downlo...ad-pixel-test/

George

[JBW]

Thanks Dave all I could get visible was one with a link to the second.
Brian