Tracking airplanes (and maybe ISS) - cheap, reliable solutions?

[nfotis]

Hello everyone,

 

in recent days I was playing with tracking airplanes with my Canon 100-400L IS II lens (and a 1.4x extender) on my crop sensor 80D.

The results were OK, but even with an effective 900mm lens (in film terms) these twin jets are quite small in my images shot while flying high.

I was thinking about using my Skymax 180 or my C9.25 as a possible tracking scope for these targets, but my own mount is a HEQ5 Pro GEM, which doesn't seem very suitable for the task.

An idea was to use a manual AltAz mount and try to manually track the overflying airplanes using my Canon or an ASI462 camera (I suspect the latter will be harder to keep the airplane in frame).

I append  a typical view with my Canon lens, and a typical crop I would like to attain with a scope, to give you an idea.

 

Cheers,

N.F.

 

 

[vlaiv]

I don't think you'll find anything cheap and reliable for this purpose.

Tracking mount needs to know trajectory in order to track objects. Either that, or to have some sort of guiding / feedback on object position.

Best place to start is to calculate angular speed of airplanes depending on their distance / altitude / direction and speed. You also need to consider tracking "resolution" / "precision" (think of it as stepper motor steps or servo motor encoder resolution) and max speed at that resolution.

I think that you will find that stepper motors are not very suitable for the purpose as they have slow max speed and that high resolution encoder servos are not cheap.

[inFINNity Deck]

What you would need for this is a infra-red tracking mount like this SAT/SAGEM Minilir in my collection. These lock-in into the heat of the plane's engines. For filming they were equipped with a camera, making it a cinéthéodolite. Mine is from 1980, not even sure if it still works (probably not, last serviced 25 years ago). Needless to say that these are expensive toys when new, but they may pop-up at militaria auctions (but then they may be defective).

Nicolàs

[vlaiv]

2 minutes ago, inFINNity Deck said:

What you would need for this is a infra-red tracking mount like this SAT/SAGEM Minilir in my collection. These lock-in into the heat of the plane's engines. For filming they were equipped with a camera, making it a cinéthéodolite. Mine is from 1980, not even sure if it still works (probably not, last serviced 25 years ago). Needless to say that these are expensive toys when new, but they may pop-up at militaria auctions (but then they may be defective).

Nicolàs

That is interesting piece of kit.

I'm not sure that I would go that route though.

Today it is much much cheaper to do visual tracking. Simple guide scope with guide camera (relatively wide field) and a bit of software based on OpenCV can be used for tracing of object.

Problem is precision / stability and speed of tracking of the mount itself.

[fireballxl5]

@vlaiv that looks like cool and interesting software, thanks for the YT link.  Do you know of any apps that have utilised OpenCV to drive an astro mount for either daytime or nighttime applications?

[vlaiv]

3 minutes ago, fireballxl5 said:

Do you know of any apps that have utilised OpenCV to drive an astro mount for either daytime or nighttime applications?

No. I just remembered that OpenCV is used in robotics and security applications and that it can do object tracking (there are bunch of videos on that subject on YT - I found short one - just for demonstration).

I don't think it would be hard for anyone who is good at programming to develop software to direct the mount depending on this input.

There are a lot of examples in Python (or other languages like C++).

If I was interested in doing something like that - here is where I would start:

- doing some basic calculations on aircraft angular speed depending on height, actual air speed, direction of travel and position relative to observer (worst case scenario is directly overhead at low altitude and high air speed).

- I would asses attainable and expected resolution (aircraft image size in terms of pixels and angular size based on size of aircraft and its distance) and expected exposure length to suppress motion blur.

- would then look if regular stepper motors can provide that sort of tracking speed and precision on something like SkyTee2. That mount has needed payload capacity, is affordable and can easily be equipped with stepper motors (it already has slow motion controls with reduction).

That is of course DIY approach - but does not address original question - ready made solution. My only concern is that cheap part of original question can only be addressed with DIY.

[nfotis]

In my original post, I wrote about the possibility of manual tracking.

Would this be workable?

N.F.

 

[EarthLife]

It's not a difficult thing to do, but finding the software to interface with your camera and mount setup might be.

I've done it myself by writing a simple piece of optical tracking software for my camera and mount, it simply tracks an object that appears in view, it tries to keep it centered but smooth tracking is the priority, easy enough once it see's what direction the object moves across the camera image (the frame rate has to be high enough).

The difficult bit is to first get the desired plane/object within the telescopes/cameras field of view, once that is done the object tracking software takes over with ease - so long as the object doesn't do sharp 90deg turns like all the imaginary UFO's do

 

[vlaiv]

14 hours ago, nfotis said:

In my original post, I wrote about the possibility of manual tracking.

Would this be workable?

N.F.

 

I've seen some images of ISS taken with large manual dob.

I was seriously impressed - but I don't think it was manually tracked - but rather - push / capture fly thru, push / capture fly thru and so on multiple times to accumulate enough frames for stacking.

[EarthLife]

One thing you have to be very careful of tracking sky-ward objects during the day time is the Sun !!

It would only take a few millisecs to destroy a camera sensor or your eye ball/sight.

When using object tracking software that can be avoided by having the tracking software stay well clear of where the Sun is at that time (assuming it knows the current Sun's position and also the telescopes location and pointing).

When doing manual day time tracking your eye's and/or camera sensor could very easily be destroyed in a flash. NO 2nd CHANCES !

Edited June 24, 2022 by EarthLife

[nfotis]

2 hours ago, vlaiv said:

I've seen some images of ISS taken with large manual dob.

I was seriously impressed - but I don't think it was manually tracked - but rather - push / capture fly thru, push / capture fly thru and so on multiple times to accumulate enough frames for stacking.

Oh, I think that there's a terminology problem on my part.

When I say "manual tracking" I mean something like these manual Dobsonians did following the ISS (is "manual push" the correct term?)

So, I could/would use an AltAz mount like the Rowan 75 in manual (with a long pole) and shooting with the camera while turning the scope?

 

Adding a manual tracking system with eg a joystick would be another level of cost/complexity.

 

N.F.

 

[vlaiv]

29 minutes ago, nfotis said:

So, I could/would use an AltAz mount like the Rowan 75 in manual (with a long pole) and shooting with the camera while turning the scope?

Thing is - moving manual mount with either slow motion controls or simply pushing it by hand creates vibrations. You don't want constant manual tracking - you want to manually position it at the path of object and then let the object enter the FOV while you are filming but the scope itself is stationary (no shakes that way).

[VectorQuantity]

On 22/06/2022 at 22:33, nfotis said:

Hello everyone,

 

in recent days I was playing with tracking airplanes with my Canon 100-400L IS II lens (and a 1.4x extender) on my crop sensor 80D.

The results were OK, but even with an effective 900mm lens (in film terms) these twin jets are quite small in my images shot while flying high.

I was thinking about using my Skymax 180 or my C9.25 as a possible tracking scope for these targets, but my own mount is a HEQ5 Pro GEM, which doesn't seem very suitable for the task.

An idea was to use a manual AltAz mount and try to manually track the overflying airplanes using my Canon or an ASI462 camera (I suspect the latter will be harder to keep the airplane in frame).

I append  a typical view with my Canon lens, and a typical crop I would like to attain with a scope, to give you an idea.

 

Cheers,

N.F.

 

 

There used to be fairly inexpensive software for this from optictracker.com. I considered purchasing it a couple of years ago but never did. It seems it's now no longer sold.

https://www.youtube.com/user/optictracker/featured

 

Edited June 24, 2022 by VectorQuantity

[wornish]

Think using a DSLR hand held with a telephoto lens and in built image stabilisation would be a lot easier, but not such a technical challenge.

If you use a M43 camera you have the benefit of a 2x crop factor.

This was taken with my Olympus M43  EM1mk2 with 300mm + 1.4TC  ( 840mm Full Frame equivalent)