Asteroid Zoo Talk

Odd object

  • planetaryscience by planetaryscience

    What exactly is this?

    It's not a meteor, artifact, or satellite. It shows up on all 4 frames, and It's not a diffraction spike. Diffraction spikes here are vertical. So I ask you, what is this?

    Posted

  • scibuff by scibuff

    Hmm, interesting. Even a diffraction spike would be moving in the same pattern as the artifacts. So would anything on the CCD or in the optics, or even a bad CCD readout (all of those would move relative to the bg stars)

    could be something added by a post-processing routine such as png export

    Posted

  • planetaryscience by planetaryscience

    Well it looks fairly 'natural'- as in it isn't uniform and appears to disappear near the top of the picture. I can't think of any processing artifact that would cause this, unless possibly the CCD was broken and we're looking at a crack mark?

    Posted

  • scibuff by scibuff in response to planetaryscience's comment.

    but it if were a part of the CCD or the telescope optics, would move relative to the stars just as the artifacts move (because the telescope is dithered between individual frames). Appearing at the same exact place relative to the stars (while artifacts clearly move) rules out it being a part of the aparatus

    Posted

  • planetaryscience by planetaryscience

    Well whatever we come up with as an explanation, we can't have any certainty of it unless some scientists show up over here.

    Posted

  • Ptd by Ptd

    Image AAZ000161k

    Similar artifact here

    Posted

  • ElisabethB by ElisabethB

    What if it is a slow moving fast moving object ? 😄

    Or it could be a glitch !

    Posted

  • Cpt._Pete by Cpt._Pete

    I`m going for laser sight from another scope

    Posted

  • planetaryscience by planetaryscience

    @Cpt._Pete pointed out something that we'd overlooked- is it possibly the laser that telescopes sometimes put in the air to adjust for seeing when there are no guide stars to see?

    Posted

  • Del_Congdon by Del_Congdon

    I was thinking laser too but, with my lack of experience painfully obvious to me, I was afraid to pitch in. It would explain its stable appearance in all four frames.

    Posted

  • enderb by enderb

    I'm just thinking out loud but it might be some sort of linear lens glare. That is probably incorrect but y'know, you need to throw out ideas sometimes.

    Posted

  • planetaryscience by planetaryscience in response to enderb's comment.

    What you are describing is a diffraction spike, which in these images are vertical/horizontal.

    Posted

  • Dr.Asteroid by Dr.Asteroid scientist, admin

    It's a diffraction spike. I'm looking through the data to give a good example and when I find one, I'll post it here. The spider that holds the detector (this particular kind of telescope has a detector pointed down at only one mirror) is tilted 45 degrees from up/down on the detector. If it's a feature that is vertical in extent, that's usually bleed - where there was so much light that the electrons filled the pixel and began flowing up and down on the column.

    So, up and down = pixel overflow.

    Tilted 45 degrees = diffraction spike.

    Posted

  • planetaryscience by planetaryscience

    Interesting. I suppose the horizontal lines are star bleed too?

    Posted

  • Dr.Asteroid by Dr.Asteroid scientist, admin

    I've packaged up an image that I was working with for some other things. Ignore the little circles - they're for something else. But I annotated something that looks like the above image. This also would give context to how large the full images are.

    https://www.dropbox.com/s/tbtt0v4ma5plqco/far_field_spike_annotate.png

    The horizontal lines near the stars are likely bleed - but it's much easier for charge to travel along the columns.

    Posted

  • planetaryscience by planetaryscience

    Thank you. While on the topic of artifacts, what are the black streaks in some images? The artifact is visible in your included image at the bottom center right.

    Posted

  • Dr.Asteroid by Dr.Asteroid scientist, admin

    I don't know. I will inquire further.

    Posted