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Ghost Crater (Astroavani/Brazil-2012)


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With only 2 months left to complete 10 years of the ghost crater discovered by me, I present a new photo in better resulution of the formation in question and take the opportunity to transcribe the original text with some minor adaptations.
"I've always had the greatest interest in astrophotography of Lunar formations and from the beginning, using mainly the Virtual Moon Atlas, I tried to find and know the most striking features of the regions I observed or photographed.
As time went by, I acquired a better knowledge and more easily recognized these regions and their main accidents, which greatly facilitated the perception of anything that clashed with the traditionally observed landscape.
So on January 5, 2012, photographing the region near Plateau Aristarchus, I noticed a strange depression that caught my attention. I tried to locate it on lunar maps and even in the Virtual Moon Atlas, but I found nothing.
I searched the internet, asked for help from colleagues in Brazil and abroad to clarify what this training could be, I believed that it should already be known or that others had already observed it.
In principle, I couldn't find any reference to this lunar formation.
Looking at the attached photo, the impression we have is the existence of a depression that is only revealed when the Sun is at a very low angle of illumination.
I sent the original photos to my friend Vaz Tolentino from the Lunar Observatory (VTOL) back in 2012 and he gave me the following explanation: Indeed, your photo, due to the angle of sunlight, captured an interesting and unusual circular depression, which has along its southwestern rim, the crater WOLLASTON D (5km in diameter). The formation is very strange in that it doesn't look in the style of known ghost craters. The strange and unusual thing is that, it appears that the supposed crater was flooded by basaltic lava and, instead of filling up and leveling off with the surrounding outer floor, it only filled a little and didn't even out, remaining like a "gourd" or "bowl ", in addition to leaving no traces of a central peak. This depression appears to be about 42 km in diameter, being slightly larger than ARISTARCHUS. I checked LRO images and unfortunately I can't identify anything due to the sunlight being high in the photos. We need more photos of this region, in light conditions similar to the one in this photo.
At Alexandre Amorim's suggestion, I decided to contact BAA (http://www.baalunarsection.org.uk/) Lunar Section where I made contact with Dr. Anthony Cook. I sent to the same the photos obtained by me in January and June 2012, as well as I reported the suspicion that the referred depression had not yet been catalogued. After exchanging several emails, I received the following message from Dr. Cook, which I transfer in full:
On Mon 4/06/12 07:06 , "Tony Cook [atc]" atc@aber.ac.uk sat:
Dear Avani,
Thank you for your images. It looks like a buried ghost crater that you have found. Please keep on looking for another ghost craters elsewhere on the Moon because I think that there may be quite a few that are visible near to sun rise or sunset that remain to be discovered. I think this work will be of great interest to Peter the Greek. Also I like the quality of your images. If you would like to take images on the dates and times that are listed in:
http://users.aber.ac.uk/atc/tlp/tlp.htm ...
and find Brazil, then this could be very useful for my own research in disproving some TLP observations from the past.
Many thanks
Dr Anthony Cook Institute of Mathematics and Physics, Aberystwyth University, Penglais, Aberystwyth, Ceredigion. SY23 3BZ. United Kingdom
In April 2013 using the new QHY 5L camera, a color CMOs dedicated to high resolution Lunar and planetary photography, I got a more detailed photo of the place where the depression was located:
This allowed colleague Vaz Tolentino to trace the altimetric profile of depression and perform the following analysis:
"Dear Avani and Amorim:
Analyzing the Avani photos (January/2012 - April/2013), together with the altimetric profile that presents a classic phantom crater depression, I reach the conclusion that, most likely, it is the discovery of a new phantom crater without cataloging.
Also analyzing the altimetry of the ghost craters DAGUERRE, LAMONT and that discovered by VTOL in February 2011, I came to the conclusion that they have very similar altimetric profiles, and the Avani ghost crater is a little shallower (46 km of diameter per 130 m depth) than DAGUERRE and LAMONT (both approximately 400 m deep).
However, Avani's ghost crater depth (130m) is more compatible with the ghost crater discovered by VTOL (which is approximately 100m deep). What this means?
It means that, in the past (at the time of the ancient selenographers), when the main interest in observing the Moon was to map its relief, identifying and naming its formations, they did not have the current technology, that is, shallow formations like these two Phantom craters (Avani and VTOL) are very difficult to see through an eyepiece, to be sure of what you are actually looking at.
After the initial period of cataloging and naming relief formations, lunar map drawings and other studies, the space age arrived. The first robotic lunar probes (Soviet and American) and the manned landings of the APOLLO missions had other scientific goals than discovering new, uncatalogued formations. Furthermore, even in the very high resolution photos taken by modern robotic lunar probes (SELENE, LRO, GRAIL, etc.), the images were mostly captured with sunlight coming from above and not obliquely, which makes it difficult relief enhancement and does not facilitate the identification of shallower formations such as these phantom craters.
For modern selenographs, only after the technological evolution of digital cameras (CCD and CMOS), together with the evolution of telescope optics (large and good mirrors and also APO lenses), combined with the favorable angle of incidence of light on the lunar surface, it became easier to identify new smaller formations, "camouflaged" and not cataloged on the Moon.
Congratulations Avani Soares on your discovery!
Another point marked by the new generation of Brazilian selenographers. A hug from the VTOL team!
In this way, I believe that any misunderstanding regarding the existence and identification of the aforementioned training is ruled out, only lacking the official disclosure and recognition to crown the aforementioned work."

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