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OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

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Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#11

Post by dukeofdoom »

andrewxdiamond wrote: post #9
dylan604 wrote: post #8

Earlier quoted context omitted.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens,…

What is the benefit of using robotics to move the camera over image stabilization software in post? Is it simply image quality? Or are there more trade offs?

You need a long exposure to let in enough light for stars to become clearly visible. If you expose for longer than ~ 30 seconds, then the earth will rotate enough to start causing star trails. This will physically rotate the camera to counteract earths rotation.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#12

Post by sdfsfsrgg »

dukeofdoom wrote: post #10
dylan604 wrote: post #8

Earlier quoted context omitted.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens,…

I'm not sure if that is correct. It says on their website it's a start tracker. https://www.moveshootmove.com/

It can do both. They seem to use the product's name ("move-shoot-move") to refer to a mode which both tracks the stars and moves independently, creating a panning timelapse.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#13

Post by dylan604 »

dukeofdoom wrote: post #10
dylan604 wrote: post #8

Earlier quoted context omitted.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens,…

I'm not sure if that is correct. It says on their website it's a start tracker. https://www.moveshootmove.com/

Interesting. I didn't realize there was a product/company with that name. Shoot-move-shoot is a common saying in motion controlled photography, and that was what I described.

I love the age we're in where anybody with a little know how can cheaply/affordably build something that was only available to the very well funded before. Each one of these are attempting the same thing, but trying to avoid the pain points each dev has seen from other products.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#14

Post by dheera »

dukeofdoom wrote: post #7

How does this compare to something like move-shoot-move? I think that one costs only $200. Is it even worth it to DIY.

Almost everything is cheaper to buy than to DIY. This is a hacker forum and people like to DIY for other reasons than cost, including customization, the learning experience of building something yourself, being fully FOSS, not waiting for long lead times in some locations, and other reasons.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#15

Post by dylan604 »

andrewxdiamond wrote: post #9
dylan604 wrote: post #8

Earlier quoted context omitted.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens,…

What is the benefit of using robotics to move the camera over image stabilization software in post? Is it simply image quality? Or are there more trade offs?

The is a common question, but there are certain things that are just better done in camera than post. Then there are situations where a combination of in camera + post provides optimum results. Astrophotography is one that can and does use both. The longer you can expose, the more information obtained. For ultimate long shots, you need to compensate for the earth's rotation. You continue to snap away all night, and then take those images into post where you stack the images. The stacking software adds the data together resulting in a single image that is the equivalent of a single image with an exposure time equaling the sum of each shot.

Why do this? If you do single long exposure, there is a very good chance your image will have an airplane fly through, a satellite streak by, or something more terrestrial like a fellow stargazer shining a laser through your frame, car headlights, etc. Taking a series of short exposures limits those issues, and if it happens, you throw out that shot and only loose 45-60 seconds instead of 15 minutes.

Stacking can also use shots you take when the lens is covered called dark frames. You take this for the same exposure time as the normal shots. This provides a noise pattern that builds up in any electronic sensor as the heat builds up from staying energized for so long (as well as natural summertime heat). That noise pattern can then be subtracted by the stacking software. The stacking software can also realign the images so you can use shots from multiple shoot days (er, nights).

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#16

Post by rripken »

MetaWhirledPeas wrote: post #3

This is nice! Is there something similar that's simpler and dumber, that just handles the rotation but doesn't try to locate objects?

Barn door trackers.

https://en.wikipedia.org/wiki/Barn_door_tracker

https://hackaday.com/2013/08/08/building-a-barn-door-tracker...

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#17

Post by dheera »

dylan604 wrote: post #8
dukeofdoom wrote: post #7

How does this compare to something like move-shoot-move? I think that one costs only $200. Is it even worth it to DIY.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens,…

Their marketing is a little dishonest though.

https://i.imgur.com/QD32T7r.png

They show all the other trackers with an Alt-Az wedge, but show their tracker without that piece, to make the other trackers look big.

With the specific 2 other trackers pictured, you can detach that wedge and use them exactly like the MSM tracker without their Alt-Az mounts and they would be a lot smaller.

Personally I own a SkyGuider Pro and use it with a pan-tilt head tripod and no wedge.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#18

Post by rripken »

teraflop wrote: post #4
MetaWhirledPeas wrote: post #3

This is nice! Is there something similar that's simpler and dumber, that just handles the rotation but doesn't try to locate objects?

Here's a very simple one-axis tracker using a 24-hour clock movement and a 3D-printed GoPro mount: https://hackaday.com/2018/06/03/3d-printed-clockwork-star-tr...

That really is a great hack if your camera is light enough. Genius.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#19

Post by dylan604 »

dheera wrote: post #17
dylan604 wrote: post #8

Earlier quoted context omitted.

Shoot-move-shoot does what it sounds like. It moves the platform, allows time for the movement to settle, snaps the shot, then moves again. Astrotrackers like this are constantly moving at the same rate that the earth spins on its axis. This allows for the subject to remain in the same poistion in the frame during super long exposures. Depending on the accuracy of the polar alignment and the focal length of the lens,…

Their marketing is a little dishonest though. https://i.imgur.com/QD32T7r.png They show all the other trackers with an Alt-Az wedge, but show their tracker without that piece, to make the other trackers look big. With the specific 2 other trackers pictured, you can detach that wedge and use them exactly like the MSM tracker without their Alt-Az mounts and they would be a lot smaller. Personally I own a SkyGuider Pro…

Haha, I noticed the same thing. I've started watching some of their tutorial videos, and have some other nit picking comments as well. However, these will probably get someone that's never done astrophotography up and running with the ability to get some great shots totally unachievable 15 years ago in this price range.

Re: OpenAstroTracker: A cheap 3D-printed tracking mount for DSLR astrophotography

#20

Post by emptybits »

This is quite brilliant.

Here's another approach to tracking, employed by Pentax and maybe others: Use 5-axis sensor movement to track stars (i.e. use the motors which move the sensor for in-body stabilization)

Given GPS coords, software can do this to the limits of sensor movement afforded by the camera body. I don't have a Pentax but modern models can apparently track for at least 4 minutes.[1] (!)

In theory, official or unofficial firmware for other models of camera might be able to do the same.

[1] https://milkywayphotographers.com/article/2021/01/21/pentax-...

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