How to Confirm Finds? (Take 2)

Introduction | Nova | Preliminary Conclusions | References

On this page, I will go again into the question of how to confirm that you have actually photographed or seen the intended sky object. I already wrote the essentials in the article How to Confirm Finds? (Take 1) and these can be read there. Here I just add first experiences with so-called "plate solving" applications, more precisely, only one, namely





So the basic question is when doing quick astro photography, fort example, with the eVscope: Is what you see in the eyepiece or on the smartphone screen indeed the sky object you are or were looking for? In the meantime, there also came up the question of which celestial objects one sees at all; this is especially true for small galaxies.

Successful Finds

First, I would like to address the successful finds! Unlike visual observations, photography provides a result that can be easily compared with photos or sketches from books or the Internet. My preferred sources are described on page How to Confirm Finds? (Take 1) further below. In addition, the eVscope delivers a result that is more similar to that of cameras than to the visual impression. Therefore, comparing photos with photos is usually preferable to comparing them with drawings, which usually correspond to the visual impression. But I often use both to see how the individual representations differ and complement each other.

Not so Successful Finds

Now let me turn to the "not so successful finds"! When I compare my photos with photos or drawings from books or the Internet, I can unfortunately not find a match in some of them. Obviously I had photographed something completely different than intended - but what? Initially, I had the obvious idea to use astronomy programs to search the surroundings of the "unknown objects" for matching patterns. But so far my experiences with these programs have been such that I was hardly able to establish a relationship between what the camera photographed and what the programs show. In other words, the programs do not help me in my search.

The Solution: Plate Solving

So I looked for other solutions. And that is when I came up with the term "plate solving," which stands for algorithms that can recognize which part of the sky a camera or a photo shows. I had already stumbled across this term in connection with the eVscope, because it uses this technique itself to find objects in the sky. But I had not pursued this topic any further, particularly since I did not see any practical use in it for me at first. But after so many failures in photographing open star clusters with the Atik Infinity camera, plate solving appeared to me as a viable approach way to find out what the camera actually photographed. This impression was also confirmed when I came across the Website of Dietrich Kracht, who describes this method and programs in detail (in German). More about this on page How to Confirm Finds? (Take 1) > Plate Solving!

At the beginning of 2020, I had a similar problem with the eVscope: On some of the photos that I took with the eVscope, it was not clear to me whether the object on the photo (or as it was labelled on the photo) was really the object I was looking for. Visual comparisons with my books did not always lead to success, and so I resorted to the plate solving method!



Dietrich Kracht describes two plate solving applications, All Sky Plate Solver and Nova The latter is a Website that allows you to find out which part of the sky is shown on photos (instructions for Nova by Dietrich Kracht, in German) and thus, an "easy" alternative to All Sky Plate Solver. In contrast to the latter, you have to be connected to the Internet (there also seems to be available a way to work offline using Windows). As with All Sky Plate Solver you start from photos, but upload them to the Website and have them be processed there.

One advantage of Nova is that you get sky maps right away and do not have to enter coordinates into an astronomy program to see the corresponding part of the sky.

I tried Nova with several photos taken with the eVscope. These were photos where I was not sure what they showed or whether they were labelled correct. Here are some examples!

NGC 884/869

NGC 884/869 - eVscope, processed (below NGC 884)

NGC 884/869 - eVscope (far left of NGC 884)

NGC 884/869 - eVscope (NGC 884)

M 35, M 36, M 38

M 35 - eVscope

M 36 - eVscope - wrong label

M 38 - eVscope


Preliminary Conclusions

With Nova, thanks to the Website of Dietrich Kracht, I found a solution that make it quite easy to determine which sky objects my eVscope (or any other camera) photographed. Meanwhile Nova has become the "tool of choice" for me, when it comes to plte solving.




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