Hi friends,
I'm setting up Ekos for work with LISA spectrograph. There are 2 cameras on it. One for guiding one for collect spectra. I have created sequences which include all necessary jobs. Move to the target, plate solving, correction, calibration frames with neon lamp (using simple python script), images of standard star, target star, move to the next target and so on. The problem is with guiding. Both internal guider and PHD2 are not able to automatically move the target star to the slit position. OK, I can do this one step manually. But I have to watch carefully the job progress to be ready when guiding starts. Because EKOS don't wait. It starts guiding on automatically selected star and the spectra capturing starts immediately or with defined delay. Of course the automatically selected star is not always the target star and it is never in the slit position. Is there any way to prevent EKOS to start the guiding process automatically?

Pavol,

I'm not familiar with spectroscopy, so forgive my naive response, but, assuming the two cameras' center position was identical
(or you adjust the target position to compensate for that), then couldn't you just:

(a) put the slit in the center of the image,
(b) plate solve with a low-enough accuracy constraint such that plate solving moves the target to the center (slit) position,
(c) guiding should just keep it there
(d) begin imaging

and all works automatically?

HI Hy,
Your approach was my initial idea. Let clarify why it doesn't work.
1st - Actually for plate solving I use third camera installed on finderscope. Mainly because the FOV. The plate solution is quick and always successful on finder. But the finder and the main telescope are not exactly aligned.
2nd - I tried to use guiding camera on the main telescope for plate solving. Unfortunately the FOV is too small. The process fails often.
3rd - for mechanical reasons put the slit exactly in the center of the image is not an easy task. Moreover it moves slightly, few pixels, as the telescope is pointing at different parts of the sky.

What is the field of view of your main telescope (where you say you can't reliably plate solve)?
I regularly plate solve with a field of view of 30' with no major issues.
It's true that you might need to increase exposure time, or adjust some of the StellarSolver parameters to get this working.
I've used both the internal solver as well as ASTAP successfully at that field of view.

Assuming that your field of view isn't way more narrow, please point to a fits file you have trouble solving and I'll try and send you parameters.
Hy

The FOV is ~ 7 arc min. However astrometry.net is able to solve such small field if enough stars can be detected. Normally 30 seconds exposure is needed. I made some effort to make it work. But the problem with mechanical torsions and slit shift still remains. So I decided to look for semi-automated solution. With PHD2 alone there is an option to switch off the autostar selection. Even in EKOS you can unselect autostar on guiding panel. But when sequence works it seems the EKOS force the guider to select the guiding star automatically.

Once guiding started, you can use Manual Dithering to move to specific coordinates.



Just make sure One Pulse Dither in guiding options is turned off.

Thank you Jasem. This is what I'm currently doing. But this procedure requires the presence of the user at the computer for at least 10 minutes always when moving to next target. For me better option would be to lose some observing time of the spectrograph when it waits for the user to start the guiding manualy. This manual operation last 1 minute maximum. And I can go away to observe visually.
But OK I see EKOS wants to do everything automatically and there is no way how to stop it. Right? Or put some script in the sequence?

did you ever work out a way of adjusting the lock position of the ekos guide module?