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4

I'm going to guess that these are reflection artifacts of one or two nearby bright stars. The fact that they have about the same length as the stellar streaks, suggests they are smeared by the telescope's tracking of the comet. The fact that they are oriented with a slightly different angle than the star streaks may be due to the reflection shifting slightly ...


0

I suspect they are brightish extended galaxies being smeared by the motion as HST tracks on the comet - you can see the star streaks e.g. in the bottom center of the image. Given the time of the image, it should be possible to identify which galaxies they were. Pretty much everything else in the image (apart from the comet) are cosmic rays - being above the ...


5

TL;DR version, Yes, yes, distortion. In more detail: HST's orbit is approx. 90 minutes so this will cause the breaks. Some more information is given in the Orbital Constraints section of the Cycle 27 guide for proposers. Since HST is having to move to track the moving comet to keep it in the (small) field of view of the instruments, it will likely need to ...


2

This GIF is made (via giphy.com) from the new NAASA Goddard video Hubble's New Image of Interstellar Object. It shows the comet moving at quite a clip! This shouldn't be a surprise. From the link in the question https://archive.stsci.edu/proposal_search.php?mission=hst&id=16009 the coordinates for the first and last exposure are: RA ...


0

Is that right? I guess not. It is easy to correct for biases in pixel sensitivity, these objects are stars and the telescope tracks them such that their light is collected into the same photon bin over time. Correction for pixel sensitivity is generally done (own experience) by taking images completely out of focus in faint light conditions. In this way ...


1

Is that right? No. The streaks are fast-moving objects in the view of the telescope -- Other satellites. Hubble is in a fairly low orbit (it can be visited) and there are plenty of satellites around and above it, including in its field of view. (For obvious reasons, the streaks are not caused by aeroplanes, a usual contender for streaks). What gives it ...


16

Is that right? Yes. Is the fuzzy one an extended object? That would certainly be my guess (probably a distant galaxy). What causes so many isolated pixels to be so much brighter than the background? Is this just the tail of a statistical distribution of shot noise, or are there other mechanisms that can produce single pixel noise many ...


7

Finding an astrometric solution from an image with Astrometry.net is usually called plate solving. As mentioned in the comments, it is based on pattern matching, using a large set of databases that are pre-computed for various field of view and plate (or pixel) scale. The ArXiv paper Astrometry.net: Blind astrometric calibration of arbitrary astronomical ...


6

Astrometry.net successfully plate-solved both images. The first image is of the Cygnus region with north to the left. It is 73° wide and 55° high, with 65 arcseconds per pixel or 55 pixels per degree. Bright stars include Deneb (α Cyg) left of center and Altair (α Aql) at upper right. The second image is of the Sagittarius region with ...


2

Has a plan or strategy been outlined or established to reduce the number of bright satellite trails that appear in LSST perpetual sky surveys, and/or to process images to remove the trails or at least flag pixel regions that contain likely trails? Indeed LSST will be very affected by satellites in LEO. The strategy is to make several observations of the ...


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