Hello all,
I wanted to address the issue of ARTIFACTS of imaging here, because I think it is important to consider this in Astrophotography. The description below, was derived from one of my posts, in which, by processing an image from the Hubble Archives, I found a really weird object. After researching this, I could not find any info, so I posted the image in case somebody had seen it. I also wrote to a collaborator of the principal investigator of the project that produced this image at John Hopkins, who graciously replied pointing me to an article describing this "object", a typical artifact found in one of the detectors of the Hubble Telescope camera WFC3 (link
https://www.stsci.edu/~INS/2010CalWorkshop/dulude.pdf).
THE MYSTERY: I was looking at Hubble archive data to process, while I wait the collection of sufficient telescope imaging of my own to process. My interest here is primarily artistic, but I also have scientific curiosity. I was looking at data in the Eta Carina area, and I found a very interesting object imaged with a blue narrow band filter (f502n). My first idea is that this was just an imaging artifact, but note that this was not found in any of the control images, only in the blue filter and the aggregate image of all filters. It looks like an "infinity symbol" composed of concentric structures (see inset). I searched the internet and literature, and I found that Eta Carina and its accompanying nebula (see little summary below) does have "sort of" a 3D structure resembling an infinity symbol, but nothing like what I see in the image. Also, I don't know the exact identity of the stars in my image, as the PixInsight plate solving protocol in AstroBin does not seem to be able to solve any of my Hubble images (any help out there?). In any case, being a scientist I am still skeptical about whether this represents a real physical phenomenon or not, but I am trying to contact the investigators in this project to see if they have anything to say. Any comment or clue is welcome.
MYSTERY RESOLVED! Thank you for those that responded. Like you and me, the suspicions that this is an artifact are correct! I wrote to a collaborator of the principal investigator of this project, and he introduced me to typical artifacts produced by the UVIS IR detector of camera WFC3 (see attached pdf of the article). In this case, this is what is called "ghost window". It is produced when a bright object reflects in the layer of filters. Interestingly, this varies with the filter, as different filters are produced with different methods by manufacturers. This totally explain the fact that I only saw this with one of the filters.
LESSONS LEARNED:
1. It is OK to be curious if you find something unusual in an image; just don't accept it as fact.
2. Lack of evidence for something is "not evidence" or anything. I mean, that somebody else has not seen it before, does not mean that it is not "something". There is an explanation by our physical laws.
3. Research the source. In this case I feel grateful that an investigator at NASA took me seriously and helped me find the source of my observation.
I hope the article is helpful
Clear Skies,
Vivian
I wanted to address the issue of ARTIFACTS of imaging here, because I think it is important to consider this in Astrophotography. The description below, was derived from one of my posts, in which, by processing an image from the Hubble Archives, I found a really weird object. After researching this, I could not find any info, so I posted the image in case somebody had seen it. I also wrote to a collaborator of the principal investigator of the project that produced this image at John Hopkins, who graciously replied pointing me to an article describing this "object", a typical artifact found in one of the detectors of the Hubble Telescope camera WFC3 (link
https://www.stsci.edu/~INS/2010CalWorkshop/dulude.pdf). THE MYSTERY: I was looking at Hubble archive data to process, while I wait the collection of sufficient telescope imaging of my own to process. My interest here is primarily artistic, but I also have scientific curiosity. I was looking at data in the Eta Carina area, and I found a very interesting object imaged with a blue narrow band filter (f502n). My first idea is that this was just an imaging artifact, but note that this was not found in any of the control images, only in the blue filter and the aggregate image of all filters. It looks like an "infinity symbol" composed of concentric structures (see inset). I searched the internet and literature, and I found that Eta Carina and its accompanying nebula (see little summary below) does have "sort of" a 3D structure resembling an infinity symbol, but nothing like what I see in the image. Also, I don't know the exact identity of the stars in my image, as the PixInsight plate solving protocol in AstroBin does not seem to be able to solve any of my Hubble images (any help out there?). In any case, being a scientist I am still skeptical about whether this represents a real physical phenomenon or not, but I am trying to contact the investigators in this project to see if they have anything to say. Any comment or clue is welcome.
MYSTERY RESOLVED! Thank you for those that responded. Like you and me, the suspicions that this is an artifact are correct! I wrote to a collaborator of the principal investigator of this project, and he introduced me to typical artifacts produced by the UVIS IR detector of camera WFC3 (see attached pdf of the article). In this case, this is what is called "ghost window". It is produced when a bright object reflects in the layer of filters. Interestingly, this varies with the filter, as different filters are produced with different methods by manufacturers. This totally explain the fact that I only saw this with one of the filters.
LESSONS LEARNED:
1. It is OK to be curious if you find something unusual in an image; just don't accept it as fact.
2. Lack of evidence for something is "not evidence" or anything. I mean, that somebody else has not seen it before, does not mean that it is not "something". There is an explanation by our physical laws.
3. Research the source. In this case I feel grateful that an investigator at NASA took me seriously and helped me find the source of my observation.
I hope the article is helpful
Clear Skies,
Vivian
