Dithering: Direct Guider - dither distance

[Ruediger]

Hello All,

since I image without guiding at a FL of 2560mm the dithering distances are by far too big when using “Direct Guider”. So it would be great to have an option to set the dithering distance in pixel or arcsec. So far I have not figured out how to set distance with built ion Direct Guider. Also I have found no clue in the documentation. So apologies when it is already there.

Thank you!
Rüdiger

[Stefan B]

The direct guider interface only allows for a duration that is sent to the mount as a guide pulse. It does not know anything about pixel scale or distance (and can’t know it). Therefore you need to reduce the pulse duration if the dithers are too large.

[Ruediger]

Hi Stefan,
thanks for the reply, but it is still not clear. It sends an impulse to the mount with the give length, but at what speed? Does it use the “Guide rate” set in the mount / ASCOM driver?

And if yes, it would be easy to calculate the dither offset by NINA, since all parameters are given: Pixel size, focal length and guiding speed. Therefore an option to set the offset in pixel or arcsec would be easy

Maybe some details it the manual would be great.

Thank you!
Ruediger

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[Stefan B]

Hi Ruediger,

N.I.N.A. uses this interface to issue the guide pulse: https://ascom-standards.org/Help/Platform/html/M_ASCOM_DeviceInterface_ITelescopeV3_PulseGuide.htm

[Stefan B]

(And the rate is not set inside NINA so uses whatever is set by the driver)

[Ruediger]

Thanks Stefan, I think I got. The link helped.

Last remaining question: NINA takes the value in millisecond (as described in ASCOM doc) or in second?

Maybe a good idea to add the unit in the frontend or as tooltip.

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[Stefan B]

The time is in seconds. I will add the SI unit next to it.

[Stefan B]

Removing version: 1.11 Nightly (automated comment)