[FEATURE REQ]: UI customizations

[ArijitKHaldar]

Tried your app out for about a week. The progress looks promising..since the last time I tried..but there are still a few things for which I am going back to other apps...which I'd like to point out.

• Colourscheme:
  Since your app is basically a duo-tone colourscheme, it would have been good to have a colour picker which let user choose the foreground and background colour. Though the yellow on black is pretty good to look at in the dark...I do face some difficulty to see under direct sunlight. I'd probably have chosen some dark on light colour during daytime..if the app allowed it..then switch back to default at night.
• Filters:
  When selecting satellites to be shown, your app gives the user to list satellites based on type of transponder, i.e., FM, NFM, CW, etc. This do sort things out a lot...but while chosing satellites for working with mobile HTs (2m VHF FM), there is no way to get a sorted list other than choosing FM, then manually selecting the satellites we personally know. I would have preferred a filter like AMATEUR, WEATHER and so on, broadly classifying the satellites, then a narrower search based on band, if chosen AMATEUR, such as FM, SSB, etc., and the band the transponder works on.
  This would narrow down the list a lot, and give users work on newer satellites without knowing the name in advance.

Another aspect of tracking satellites is amateur astronomy. This requires visibility, brightness magnitude, and a day-night separator to know which pass would be favourable for photography. For this, I suggest similar approach to the the Heavens Above app, which shows satellite icon in the list in a different colour if that pass is visible and show a brightness magnitude value when clicked. It also shows the pass track on the radar view with a thicker line for the duration of the pass till which the satellite is visible (since sometimes the satellite goes eclipsed midway between a pass for some locations). You can probably use the duration of pass bar that you have when any satellite crosses AOS to show a brighter colour if that pass is visible. I have put this in the filters section, since I think, if someone is looking for a visual pass, he/she will not want any passes that are not visible, so, that needs to be a choosable checkbox.

• Radar view:
  The radar view is still not very informative, but I'll keep my request simple here. I would prefer having a N/S/E/W marking on the radar view, since sensors on mobile phones do not always give accurate reading. Also, location of sun and/or moon on the radar would help keep a visual marker for manual tracking of selected satellite. Since you are already implementing sending the az-el values via bluetooth, this information would also help working with homebrewed sun/moon trackers without needing for additional data. If the brightness track can be added, that would be awesome.

• Notification:
  I noticed someone asked for this already, but I have a different stance. When not working with satellites, I personally do not like any apps giving me additional notification which I don't require. So, if my idea of filters are implemented, then the user can already curate his/her own choice of satellites. Then, what I want is to give an AOS beep for any of the selected satellites as long as the app is open.