First ever image - odd shape stars

Technical Support for the BRT telescope and website
Jaydeeuk1
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Joined: Sun Oct 11, 2015 10:46 am

First ever image - odd shape stars

Postby Jaydeeuk1 » Sun Oct 11, 2015 10:50 am

Don't know if this is a tracking issue but my first image has issues with elongated stars.
Not had any others back yet of same target.
http://www.telescope.org/v4request-view ... 449&back=5

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Ed
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Joined: Wed Sep 21, 2011 2:18 pm

Re: First ever image - odd shape stars

Postby Ed » Sun Oct 11, 2015 12:39 pm

This occurs when the image has been exposed for too long. The light captured from the star has overflowed what the camera can handle and has flowed into vertically adjacent cells on the camera chip. This effect is called “blooming”. Try your observation again with a shorter exposure time.

Jaydeeuk1
Posts: 2
Joined: Sun Oct 11, 2015 10:46 am

Re: First ever image - odd shape stars

Postby Jaydeeuk1 » Sun Oct 11, 2015 8:26 pm

Really? So that cameras well depth can't handle 3 minute sub's? If it was just in the brightest part of the nebula I could understand, but even the feint background stars have that issue. I'll experiment with var sub's then

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Ed
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Re: First ever image - odd shape stars

Postby Ed » Mon Oct 12, 2015 2:28 pm

It's more of a problem on Cluster Cam (and Constellation Cam) than Galaxy Cam. Particularly with the brighter star clusters like the ones in this image.

Although Cluster Cam has a smaller aperture than the main scope, its field of view is wider than its aperture is smaller. This acts to focus about 4 times more light onto each pixel for the same exposure time. Our CCD's are very sensitive so this can easily cause blooming on the brighter stars.


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