Orion with astrotracer miscalibration fix

Started Dec 10, 2017 | Discussions thread
OP Polacofede Contributing Member • Posts: 946
Re: Some more tests

chris gunn wrote:

Polacofede wrote:

chris gunn wrote:

Polacofede wrote:

This time i wanted to test the DA*60-250.

First I tried to compensate for -15º but results were not good, after some tests i decided to use just the magnetic declination value for the place -8º and it worked very well imho.

In desperation, resort to reading the manual.....

Page 8 of the manual: "Calibration is the operation to get the electronic compass to work accurately"

Page 11: "0 deg is based on True North, not Magnetic North"

Page 19: "Accuracy +- 5deg (precise calibration)"

So, it is supposed to sort out the declination somehow.

If it doesn't work well with iron adjustment for 0 deg error, probably a new calibration is required, which would be impossible using rod?

I do gps calibration without the rod. Precise calibration never worked in my camera. +-5 seems like too much when i could prefectly set a more accurate value to the location, they over complicated it by miles imho with all this magical precise calibration when they could have just given the possibility to enter it.

Expecting people to work out the local mag field, and effects of the iron in the mount etc are a bit much, I can understand what they were thinking. I do want all control and info though!

yeah! both options shall be available.

I checked my mounts/tripods with a magnet. I can't say one is worse than the other.

Still interesting results! Try for partial correction only! Testing thoroughly will be time consuming...

I submit a single shot just to show the movement quality achieved when i compensate my K3II compass.

Something i noticed again is that, if i leave the rod in a fixed position ( sticking it to the camera top ) to apply the compensation at certain camera orientation and then i turn the camera then the effect caused by the rod is not the same. This has sense to me as after re orientating the camera the way the rod "interacts" with the magnetic field and hence the compass is not the same.

Yes, I would expect that.

So, applying a workaround like this requires a bit of work on each shot, i did that by leaving the camera screen in compass mode.


yep, kind of, depending if one could think in a practical way to move the rod easily

last night, from my backyard

34 shots, iso 1250 (i think), 60s, FA*400 @5.6, i need more light and less pollution

I've only tried this with a k135, and this is certainly better.

thaks! btw, what is a K135? the SMC Pentax 135mm F2.5 ?

Bg colour is off though.

it seems will take me a while to learn to post process. I think that when i be able to go to a less light polluted site it will be easier for me.

60s! You have mastered the Rod!

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