[biz-engineer]

Once in-a-while we hear a Pentaxian complaining about his stars not perfectly a spot on milkyway pictures using Pentax astro-tracer.

But has anyone tried to cheat the astro-tracer to make unique star-trial images?
Can we tell the camera that it is not where it think it is, modify GPS coordinates so that the sensor displacement accelerate the star trials?
If I approach a magnet close to the K1 to make it think the north is the west, I should get some interesting effects right?
Where do I need to place the magnet to accelerate star trials?

[steephill]

Making star trails doesn't use Astrotracer.

[UncleVanya]

Making star trails doesn't use Astrotracer.

He wants to trick the astrotracer into moving the wrong direction to increase the effects of star trails. Personally I don’t think it will have much of an impact since the exposures for nice trails are so long and the movement of the sensor is so small.

[Bob 256]

UncleVanya has a good point, and by tricking the compass, only the pointing direction and not the angle above the horizon would be affected. You also risk the possibility of magnetizing part of the camera body with a permanent magnet, which would alter Astrotracer's ability to function properly later on. A better option would be to do star trails without Astrotracer and slowly rotate the camera around a given axis (rotating mount with a slow-motion drive), chosen at random (along with rotation speed) to get the best effect. In any case, you still get "trails", and not much else.

[MossyRocks]

You also risk the possibility of magnetizing part of the camera body with a permanent magnet, which would alter Astrotracer's ability to function properly later on.

I don't believe they use ferrous metals in Pentax bodies as I understand they are magnesium. However throwing off or damaging the compass may still be possible if using a strong magnet. As far as throwing it off to create interesting effects you can always lie to it about the focal length used (why not tell it you are running a 2000mm lens) if using a lens that doesn't communicate that.

[jeffshaddix]

If I approach a magnet close to the K1 to make it think the north is the west, I should get some interesting effects right?

If you're in the northern hemisphere and you were pointing near the north star, the stars would streak upwards in addition to spinning.

Where do I need to place the magnet to accelerate star trials?

Point the camera West, then put the magnet near the left (South) side. You should get longer streak lengths. Same for pointing East and sticking the magnet on the right (South) side.

[biz-engineer]

I've found that astrotracer can be used in reverse for smoothing the discontinuities of star trails in interval exposures. It would be best as a user selected option implemented in camera firmware. Currently, all cameras introduce some discontinuities on star trails, the time needed to acquire an exposure before starting the next.

[UncleVanya]

I've found that astrotracer can be used in reverse for smoothing the discontinuities of star trails in interval exposures. It would be best as a user selected option implemented in camera firmware. Currently, all cameras introduce some discontinuities on star trails, the time needed to acquire an exposure before starting the next.

How do you use it in this way?

[biz-engineer]

How do you use it in this way?

If the sensor moves in the wrong direction (accentuate start trials), and sensor position is reset for every new exposure (M mode, 30 sec. exposure time), there is overlap of star trials from one exposure to the next.