None of the other responses seem to answer the question "What is the name of the thing the solar filter is eliminating?"
In fact, the solar filter doesn't eliminate anything. It just makes everything a lot less bright.
The reason the white part of the sun looks so big is due to saturation of the film, CCD, or retina that you're using to look at it. ...
The part of the sun you see (but you shouldn't look at the sun except through a filter) is the photosphere: https://en.wikipedia.org/wiki/Photosphere The scattering effect in your second photo is due to the atmosphere: it can be anywhere from almost nonexistent (say in clear mountain air) to obscuring the solar disk entirely, as when you have a heavy cloud ...
I think you're talking about the effect of a "fluffy glowing ball" around the solar disk, shown on the right in this photo:
This is called solar aureole, and it's caused by the aerosols in the air, which scatter light with a well-pronounced forward peak in the phase function:
What it the outer part of the sun, that we see with our eyes, called?
I am not sure there is a single word for this, since the effect is a little complicated. We might call it "the glare of the Sun".
But there are (at least) two things that will contribute to this.
Optical and perceptual artifacts created by our visual system and by cameras when ...
You are asking about the Moon's diurnal libration. While it is small (about 1°), it is easily measurable. It is also overwhelmed by the much larger librations due to the Moon's non-circular orbit and due to the Moon's orbit being inclined with respect to the Earth's equatorial plane.
The closest that I know of would either be Nightwatch (Terence Dickinson) and/or The Backyard Astronomer's Guide (also Terence Dickinson).
I don't think either of those cover your last requirement of "telescopes of all regions of the EM spectrum like Ultraviolet Telescopes, Infrared Telescopes, etc.", though.
Both statements are correct: aperture is the most important factor, and many large aperture telescopes are resold due to lack of use.
The brightness of any object you observe is determined by the aperture of the telescope ("light grasp"). With larger objects, such as planets, the aperture also determines the resolution: the amount of detail you're ...
In Observing Handbook and Catalogue of Deep-Sky Objects, Luginbuhl and Skiff describe how hundreds of deep-sky objects look in different apertures.
For example, for galaxy M63 (NGC 5055) in Canes Venatici:
Messier 63 is an easy object for 6 cm, located 3'.5 E and a bit S of a mag. 8.5 star.
It is elongated E-W, passing just S of the star.
The broadly ...
My first telescope was a Unitron 2.4 inch (60 mm) refractor. I bought it well-used and it served me very nicely for quite a long time also. I'd recommend looking searching high and low for used scopes if it's an option for you, and if possible visiting the owner or have them bring it to you if necessary. That way you can 1) communicate with them what your ...