Flying object types
In Nebulb, flying objects are classified into 4 types: meteors, strangers, satellites/planes and ghosts.
Also, by means of the "Displayed Objects" buttons it is possible to select at any time which types of flying objects are displayed on the image.
Meteors 
As the name suggests, this type of flying objects correspond to potential meteors.
In order to discern between meteors and other flying objects Nebulb uses two criteria:
1. They must be trails of light that only appear in a single image and have no continuity in adjacent images. Keep in mind that meteors generate flashes of light that usually do not last more than 1 or 2 seconds and, therefore, appear only in a single image.2. In case enough meteors have been detected (at least more than 10) Nebulb tries to automatically estimate the main radiant, i.e. the point in the sky from which the meteors of a given meteor shower emanate. In this way, Nebulb also uses the direction of the potential meteors to classify as meteors only those that converge on the radiant of the main meteor shower (the rest are classified as strange objects).
IMPORTANT: It may happen that some satellites end up being classified as meteors, because, although it is difficult to happen, it may be the case that a specific satellite (one of those that shine only for an instant) meets the above criteria. For this reason, it is always advisable to perform a final visual check to detect and exclude possible satellites (which usually have a very white color) that have been classified as meteors.
Strangers 
Stranger flying objects can be objects of different types (meteors, satellites or space debris), but Nebulb does not have enough information to specifically categorize them.
And for a flying object to be classified as "stranger" it must meet one of the following conditions:
1. It is really a meteor, but it does not follow the radiant defined by most of the detected meteors, that is, its point of origin (radiant) is different from that of the other meteors. They are usually meteors from a secondary meteor shower whose radiant is located elsewhere in the sky.2. It could also be a small object orbiting the Earth (space debris) that upon entering the atmosphere generates a flash of light similar to that of a meteor. In short, it is an object that does not follow the same direction as most of the detected meteors.3. Nebulb has doubts whether this object is a meteor or a satellite. The trail of light of this flying object only appears in one image (not in the adjacent ones), but there are other images close in time in which trails of light appear following very similar directions. And here the doubt arises because sometimes the trails generated by the satellites are not continuous, but appear for a few seconds, then turn off and then reappear again after some time.Thus, these situations generate certain doubts to Nebulb, so it ends up classifying the objects as "strange" so that the user can review them visually and decide what to do with them. In these cases, in addition to observing the color of the trail, it is very useful to review from Nebulb several images before and after to try to see if there is any faint trail that may indicate that the object is really a satellite.
IMPORTANT 1: Regardless of the automatic classification made by Nebulb, the user can change the category of any of the detected flying objects.
IMPORTANT 2: When you run the automatic classification of meteors according to the radiant, all those meteors that do not follow the radiant are classified as "stranger" objects. That said, it is then possible to manually re-classify any of them as meteors (if you wish to do so).
Satellites / Planes 
This category includes directly all the trails originated by satellites and planes. Unlike strange objects, in this case Nebulb has no doubt that these objects are planes or satellites, since they follow trajectories that extend over several consecutive images or very close in time.
Ghosts 
Finally, this category includes flying objects of very short lengths and therefore it is not clear to Nebulb whether they are really meteors or have been generated by a spot light (such as a flare) or an artifact (derived from noise) that appears in a particular image.
Also, longer objects with an unusual concentration or frequency can be classified as "ghosts". That is, in the event that Nebulb detects many flying objects in a certain area it may also decide to classify them as "ghosts" for the user to review.
Therefore, it is always interesting to make a brief visual check to see if any of these objects may indeed be a meteor of the photographed meteor shower (because there are also short meteors).
Related Articles
Flying object detection
One of the most special functionalities of Nebulb is the automatic detection of flying objects, that is, the detection of everything that moves in the sky and are not stars (meteors, satellites and planes). Thus, by simply selecting the following ...Flying object alignment modes
Flying objects can be rendered on the final image in two different positions: 1. In the position in the sky where they appeared. 2. In the image position in which they were captured. In the case of using an equatorial mount (star tracker) during the ...Restore default flying object sorting
During stacking Nebulb performs the detection of flying objects and also automatically classifies them among: meteors, strangers, satellites/planes and ghosts. This initial sorting done by Nebulb greatly facilitates the user's subsequent visual ...Modes of representation of flying objects
Using the "Mode of representation" buttons, it is possible to choose between different ways of displaying the flying objects on the final image (to facilitate the management of the flying objects). Lines When this mode is selected, each flying object ...Summary of flying objects
At the bottom of the "Flying Objects" module there is a section where you can find a summary of all detected flying objects (by categories) and, in addition, the information of the last selected flying object (in case you have selected one). Summary ...