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Sorry about a very vague question, but how do amateurs go about discovering new deep-sky objects? I've seen a bunch of photos here that are marked as new discoveries. |
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Pinging @Marcel Drechsler and hoping he'd chime in! |
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summoning @Utkarsh mishra too |
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Hi, i am sure marcel could offer better insight regarding this topic ;) but ill try my best to explain how discoveries are done There are lots of sky survey's which were prepared for studying and finding new objects and we take help of these like DSS POSS II survey, or IPHAS halpha survey , the discoveries that are made have gone through extensive examination of these survey and amateur data, we search for specific isolated region which contains a hot star/White dwarf. The region should emit Halpha/OIII or both and should have a prominent shape size to decide about the object. when we find such objects we quickly check if it has been discovered before or not by using research papers, SIMBAD and Hash if this object does not show up in any of these then its unknown There are lots of other creteria that needs to be fullfilled before we submit for a new discovery and when it gets fullfilled we submit it and later the spectrum is obtained and then we proceed to imaging the objects using professional instruments or amateur astrophotographers currently we have found many many potential candidates which could be important discoveries the famous STDR guys have found more than 140 New objects using amateur and professional data in the end, finding new objects is not an easy job and requires thousands of hrs of work i am sure marcel can relate .. so if you are willing to find new objects make sure you are really dedicated to it hehe thanks Utkarsh |
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Hi Mayank and Salvatore, thanks for pinging me! I agree with my dear friend and colleague Utkarsh. Searching for previously unknown objects is a very time-consuming activity. On average, each candidate requires more than 50 hours of work, research and analysis. To start the work, you need a basic understanding and knowledge of how to distinguish each new object from the other. Of course, the physics behind the origin is important. How does a supernova remnant differ from a planetary nebula, for example. We therefore work with many scientists with doctorates who help us with the sometimes very difficult analysis. I have explained roughly how our work works in the description of this mosaic: https://www.astrobin.com/0qcdjv/ Of course, it is difficult to explain to you in a few sentences exactly how our research works, but I would be happy to answer more specific questions. Cheers, Marcel |
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Hello @Marcel and @Utkarsh, Thank you for the very helpful responses. Yes, indeed, it does look like a work that requires a lot of dedication and props to you both for excelling at it. A few questions if you don't mind :-). 1. By reading your descriptions, it seems like you work on specifically planetary nebulae. I guess there are other methods for other types of nebulae or galaxies? 2. When looking for conspicuous features such as a certain shape/size, I understand there are image-processing scripts to find such features in the sky surveys and then, they are perhaps manually examined and cross-checked with other sky surveys. I am not sure how white dwarfs are detected, are they detected using spectra? 3. Have there been instances where you selected something as a candidate but it didn't turn out to be one? What are some reasons for such a rejection? 4. How much success have you had with the southern sky vs the northern sky? Is the southern sky less explored? 5. I know space is vast, but is there a reason these objects weren't discovered earlier? Is it because the sky surveys can't/didn't expose for enough time on these regions (considering these are very faint)? Thanks again, Mayank (Thanks Salvatore and orlen for pointing to the experts :-) ) |
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Hello Mayank, Yes we work specifically on finding planetary nebulae, but sometimes while looking we find other stuff too like the HII region, ISM, etc but these have a very little scientific value. Planetary Nebulae are an important part of the understanding of the physics mass, loss of intermediate-mass the chemical environment of our galaxy, and in turn star formation history, Planetary Nebulae are also ideal test particles to probe the dynamics of the Milkyway and are amongst the best kinematic tracers in external galaxies, and they look beautiful too ;) . Yes, we manually examine the sky survey's carefully and many times due to human error we miss it too (sometimes depends on how good your eyes are ) LOL. We find Hot star/W.D using the GAIA database which helps us understand the temperature, distance, mass of that W.D, and using those values we decided if that W.D is capable of lighting that region up or not, it is not necessary that if a W.D is present then its the one, but it could be the one if it has those perfect values . Yes a lot of times our candidates are rejected probably as they are HII regions or not very interesting (reason: shape / is related to some bigger region, not much data on it ) The southern hemisphere is more explored as a lot of imaging has been done and lots of parts of souther skies is covered, TBH for me both northern and souther have a great chance of finding another nebula... I know there are lots and lots of out there which are yet to be discovered, every day we keep on working to uncover the hidden beauty and maybe we find a few more.... who knows? Thanks Utkarsh |