KBO encounters Options

[xtruel]

Hi,

I’m regular follower of NH and I’m also interested in the 2nd leg of the mission, i.e the 2016+ KBOs encounters. Does anyone know when operations about this leg (starting with searching objects of interest with HST or some other earth-based means, I suppose) are expected to begin ?

[hendric]

John,
Good to know, I wasn't implying you're doing byte math, just trying to give a simple example. I understand now about using -/+ math and stretching it to make gray the middle.

I think this is an example of the horizontal banding tfisher referred to. It's not perfectly horizontal, but displaces downwards a few pixels across the whole image.


Here's something interesting. Assuming these two asteroids are at the same distance (I'm using 2.5 AU, center of the belt ), they're only ~ 20,000 km apart.

[tfisher]

I think this is an example of the horizontal banding tfisher referred to. It's not perfectly horizontal, but displaces downwards a few pixels across the whole image.

Yes, that matches what I have been seeing.

Thinking a bit more, I bet it starts out completely horizontal as the image comes from the ccd. But to subtract two images, they first have to be reprojected to a common frame of reference, so it isn't quite horizontal anymore.

[tfisher]

Poking around more at the horizontal artifacts... They occur even in the images on the tutorial page. Here's a quick experiment. I took the "Image 1: Original from 2004-Jun-09 at 11:40 UT" and subtracted this image from itself translated vertically by one pixel. Then I remapped colors so nearly equal values are white and all others are black. The result is attached, showing approximately horizontal lines where there are equal pixel values just above one another.

Interestingly, the "Image 2" has almost to-the-pixel identical lines. If this was coming from a ccd readout problem I would have guessed they wouldn't match up so well. So maybe it is a bug from the image reprojection step?

Attached thumbnail(s)