Why does one image look better ?

Filters are very important in astronomical observation as they reduce glare and light scattering, increase contrast through
selective filtration, increase definition and resolution, reduce
irradiation and lessen eye fatigue.

image

                                         Working of a magenta filter

Depending on which object you are looking, one chooses the appropriate filter. For instance the cover photo is without and withthe moon filter.

And on an amateur telescope they is how they are inserted.

image

                                        Eye-piece filter (Source)

Telescopes like the Hubble have plenty of these filters stacked on them. You can find a list of the filters here.

Some popular filters commonly used are as follows:

Red –                           R

Green –                        V

Blue –                           B

Infrared –                      i’

Ultraviolet –                  u’

Hydrogen Alpha –       H-alpha

Oxygen III  –               OIII

LPR (Light Pollution Reduction)

Neutral Density filter  and so on…

Now here’s an image of the pillars of creation captured in various filters:

image

Observe that the maximum number of stars are visible in the B, V and r’(infrared) filters. Therefore, combining these three image yields a standard image like the one you find online.

That being said, in our next post, we will run through a quick tutorial on how to access the Hubble archive and retrieve any image with any filter of your choice.

Have a good one!

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