plate solve mistery

[ajtdebruin]

Dear all,
Tonight I started with AA9 for spectroscopy. I use an ASI174 for plate solving through the C11. Fov = 13,93' x 8.75'
First I take an image and then solve which goes very fast.

Then I open the telescope window and use the <expose and center> option.
It then takes exactly the same image and then message appears: "cannot plate solve"

I am puzzled and can't understand what goes wrong and in this way can't point the scope to a star........
I hope someone can help me!
Cheers, Arnold

[fabdev]

Hello,
maybe the command you needed at the start of the session was Sync, not Center:
Click "Sync..." then "Last image":

The Centering Window uses the current approximate coordinates of the telescope, so it will now work at the beginning of a session when they are not set at all. The tolerance can be set from 1 to 10 degrees:

So at the beginning of a session, you need Sync first, and there is no need for Centering.
Sync could be avoided only if the telescope coordinates are already set (with the tolerance above).
Once everything works, I suggest to set the plate solve tolerance to 2%.
Fabio.

[ajtdebruin]

Thank you Fabio, I will try this hopefully tuesday night. Weather is not so good at this moment

[ajtdebruin]

Fabio, still a bit confused.

Am I correct thinking the sequence (at startup) is as follows:
1. use telescope goto to go to a position
2. use camera control to make an image
3. use tools/plate solve to solve
4. got back to telescope and sync
5. use exposure+center to really find the required star

If true, isn't that a bit redundant or complicated? Wouldn't a command like goto with solve and sync and/or center be more easy?
I used to work with KStars where it was a sort of a solve and find iteration...

Cheers, Arnold

[Dunmunro]

Fabio, still a bit confused.

Am I correct thinking the sequence (at startup) is as follows:
1. use telescope goto to go to a position
2. use camera control to make an image
3. use tools/plate solve to solve
4. got back to telescope and sync
5. use exposure+center to really find the required star

If true, isn't that a bit redundant or complicated? Wouldn't a command like goto with solve and sync and/or center be more easy?
I used to work with KStars where it was a sort of a solve and find iteration...

Cheers, Arnold

In the camera control image tab, check the box 'plate solve' then every image will be plate solved. (also see the check boxes in the sequence tab).
Have the camera control and telescope control panels open at the same time and leave them open.
Have camera control set for a 3 or 5 second image

so if you want to use the plate solve assist to centre on a target:

use telescope goto to slew the mount to the image location
click on image-start to take image - it will auto platesolve on download
click on goto sync - sync on last image
click on goto again and the target will be perfectly centred.

If you want to automate the process see this script:
viewtopic.php?f=5&t=725

add your targets to the telescope goto target list and the script will automatically use a platesolve assisted goto to the target, then begin autoguiding, then autofocus and the will begin the imaging run and take a sequence of images equal the number in the script, then goto the next target in the list.

[fabdev]

...
Am I correct thinking the sequence (at startup) is as follows:
1. use telescope goto to go to a position
2. use camera control to make an image
3. use tools/plate solve to solve
4. got back to telescope and sync
5. use exposure+center to really find the required star

For a telescope which does not get its coordinates at startup, the initial procedure is:

1. Take a random image (telescope at "random" position).
2. Plate solve using a constellation or a bright star as hint.
3. Sync - that's all.

Centering is used only for the targets:

1. Goto a deepsky object.
2. Center.