"WTF is that thing in the sky?"

[ckuethe]

User Story

As a	I want to	So that
Astrophotographer and satellite observer	Identify satellites passing through my field of view	I can either plan my observations to avoid satellite interference, or identify spacecraft passing through my FoV for fun.

Acceptance Criteria

• [ ] Given an observer location, and an optical sensor (telescope?)
• [ ] When I switch to astronomy mode and set my observation time
• [ ] Then I should be able to set my FoV and see what just passed through my FoV, or what's in it now, or what's about to transit

Commentary

If this is already possible, documentation would be handy. I spent some time playing with keeptrack on my workstation (git revision 43bfb0a) and it wasn't clear how to do this.

Using actual names and numbers, I was imaging NGC2174 last night and had something pass through my 2x1 degree field of view. It was flashing (tumbling?) about once every 30 seconds and took about 4.5 minutes to transit diagonally across my frame. I would have liked to have been able to quickly enter my observer location, set the time, pick a patch of sky (either by catalog object or by coordinate), and a list of satellites passing nearby/through my FoV

[thkruz]

Most of the pieces needed to solve this are in the current code base, but I am more than happy to put a little time into making it more intuitive and easier to use. The documentation is lacking, no argument there.

I should clarify upfront that the Astronomy Mode is a work in progress to provide 1st person perspective on looking for constellations. Planetarium Mode is likely what you are looking for (with some tweaks). It gives a fixed straight up view of the satellites and stars overhead.

If you click on the Custom Sensor icon at the bottom you can enter your lat/lon/alt. Choosing a sensor type of observer or optical will have similar effects. Observer puts a small elevation mask on to account for the atmosphere when trying to spot starlink. Now deselect telescope and you can enter min/max for the range/az/el to create a bounding box. Example - elevation: 49-50, azimuth: 10-12, range: 0-50000 would create a 2x1 box that goes well into deep space.

Turning on the Sensor FOV icon will help visualize what the box looks like that you made. From the legend (top right) you can disable everything except objects that are currently in FOV (orange). This will allow you to see any object that enters your FOV.

Pressing 0 on the keyboard will set the propagation rate to 0 (freeze time). Now you can set the time to whenever you had the observation without the clock ticking forward. If you are looking at a 4.5 minute time period then you can press 1 to start the clock ticking again. Pressing the minus (-) key will slow down the propagation rate and make it easier to spot things that enter FOV, but it takes longer obviously.

The Find Satellite icon at the bottom will now let you search by az, el to see what was in that direction with a margin of error (2x1 for example). It is unfortunately limited to that moment in time.

After playing with all of that, and documentation aside, I believe you need me to:

• [ ] Create a menu that allows you to calculate every satellite that enters a sensors FOV between a start and stop time. If these were automatically put into the search then you could adjust the time afterwards to see what directions they are going.
• [ ] Fix the Find Satellite to correctly filter out objects in Az/El (doesn't look like it is working correctly)
• [ ] Possibly add another reference frame for searching/sensor creation. I am not super familiar with astrophotography but happy to learn - do you use RA/DEC? If you can point me in the right direction it is fairly easy to offer more input options and then just convert it before using all the other premade features.
• [ ] Fix Planetarium Mode filters to allow looking at just objects in FOV
• [ ] Add adjustable FOV so that you can see closer to the horizon. Ideal solution is likely centered on your camera's vector, but I have had a heck of a time getting the camera to work the way I want, it may take a bit to figure that out.

Thoughts?

[ckuethe]

I figured that all of the bits are there and that I'm just using it wrong. This is the first time I've really started playing with kt.s so I'm sure that there are features of which I am unaware.

Astrophotography targets are specified as RA/DEC, and many popular targets are simply specified by catalog number, eg. M42 = Messier 42 = Orion Nebula = 05h 35m 17.3, −05° 23′ 28″. Some observers use telescopes on equatorial mounts which might be less amenable to grab-and-go use but provide better tracking; in my case I was using an alt-az mount so I had both Az/El with respect to my location, as well as RA/Dec. I would make heavy use of a shortcut that allowed me to quickly specify an observer based on a catalog number and a field of view, and I'm glad to hear that such a feature is not completely ... out of scope. :)

As mentioned in #384 I know the time of the observation, and the location, and my look angle - it would be entirely satisfactory set the time with the time menu, and use that to filter objects in my FoV.