align issue?
Jasem Mutlaq
mutlaqja at ikarustech.com
Thu Sep 2 21:38:59 BST 2021
Good question.
This was actually a solution to a problem we had. Align was always working
on current telescope coordinates. When capture and solve is executed, and
if SLEW to target is selected, the target was whatever the mount
coordinates were WHEN you capture & solve was invoked. However, this DID
result before in changing the actual target post alignment either due to
mount drift or guiding pulses ..etc. This eliminates the issue, and sets an
explicit target for align to SLEW to.
So when a user starts a sequence, the target is locked to whatever the
mount is at that particular point in time and this is used throughout the
session. This is intended for use with plate solving. Remember that after
platesolving is done, the mount coords indeed matches the target (within
the tolerance) because we perform SYNC followed by GOTO. I hope this clears
things up.
--
Best Regards,
Jasem Mutlaq
On Thu, Sep 2, 2021 at 9:22 PM Hy Murveit <murveit at gmail.com> wrote:
> If you want, comment on my kstars-devel thread, but I want to ask you, why
> would we ever do what's on this line?
>
> https://invent.kde.org/education/kstars/-/blob/master/kstars/ekos/align/align.cpp#L3291
> I can see that you wrote or re-factored at least the last version of this
> in 65b0f85d535d179d1e11c22f7841527c49b15dda
>
> We're changing the target to where the mount thinks it currently is, but,
> if we then align, then it doesn't matter what the mount thinks,
> what matters is what the plate-solver thinks. But since we've changed the
> target coordinates, the plate solver will now move the image.
> I think that's wrong, as far as I understand it--unless the user is
> running without plate solving. But I think everyone runs with plate solving
> these days.
>
> What would go wrong if that line was eliminated?
>
> Hy
>
>
> On Wed, Sep 1, 2021 at 9:52 PM Jasem Mutlaq <mutlaqja at ikarustech.com>
> wrote:
>
>> Hello Hy,
>>
>> That's right, setTargetCoords is what actually changes what align module
>> aligns to. So the question now is why does the repeated job command a
>> different coords?
>> --
>> Best Regards,
>> Jasem Mutlaq
>>
>>
>>
>> On Thu, Sep 2, 2021 at 5:48 AM Hy Murveit <murveit at gmail.com> wrote:
>>
>>> Hope you don't mind me sending you progress notes--it's therapeutic for
>>> me to debug this way ;)
>>>
>>> So far, it seems like it isn't the meridian flip at all.
>>>
>>> It turns out that the jobs is a scheduler "repeat until terminated" job.
>>> It completed its first schedule about 10 minutes before the meridian
>>> flip, at around 2:36am.
>>> At that point, the target coordinates are reset to this other spot.
>>> (Could it be a J2000 vs. JNow issue?)
>>> Also, mountmodel.cpp may call setTargetCoords()--I'm not familiar with
>>> that code.
>>>
>>> startup
>>> [2021-08-31T22:28:12.385 PDT DEBG ][ org.kde.kstars.ekos.align] -
>>> Target Coordinates updated to JNow RA: "00h 04m 23s" DE: " 16° 15' 52\""
>>>
>>> scheduler repeating job:
>>> [2021-09-01T02:36:56.423 PDT DEBG ][ org.kde.kstars.ekos.align] -
>>> Target Coordinates updated to JNow RA: "00h 04m 33s" DE: " 16° 21' 09\""
>>>
>>> I put some logging in, and will re-run tonight.
>>>
>>> Let me know if you have any insight into this,
>>> Hy
>>>
>>> On Wed, Sep 1, 2021 at 6:20 PM Hy Murveit <murveit at gmail.com> wrote:
>>>
>>>> Jasem,
>>>>
>>>> Wanted to let you know that I saw an align issue that came up in my
>>>> testing last night.
>>>> After a meridian flip, the align succeeded, but the resulting image was
>>>> shifted too far away from the pre-flip image.
>>>>
>>>> I think there's something wrong with the targets.
>>>> There are only two alignments in the log, the first one at the start of
>>>> the evening (scheduler setting up the job),
>>>> and the alignment after the meridian flip late at night.
>>>>
>>>> 1st successful align shows: Solution coordinates: RA (00h 04m 24s)
>>>> DEC ( 16° 15' 51\") ... Target is within 00° 00' 18\" degrees of solution
>>>> coordinates
>>>> 2nd successful align shows: Solution coordinates: RA (00h 04m 34s)
>>>> DEC ( 16° 21' 03\") ... Target is within 00° 00' 19\" degrees of solution
>>>> coordinates.
>>>>
>>>> The target itself is not shown in the log, but as far as I know, it
>>>> should be the same target for the two aligns.
>>>>
>>>> *Since the two solutions are a little more than 4 arc-minutes apart,
>>>> they can't be within 18" and 19" of the same target.*
>>>>
>>>> Here's the lines near the last iteration of the original alignment
>>>> early in the evening:
>>>>
>>>> [2021-08-31T22:28:02.727 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "40 stars, 27 quads selected in the image. 30 database stars, 20 database
>>>> quads required for the square search field of 0.4°. Search window at 192%
>>>> based on the number of quads. Step size at 100% of image height"
>>>> [2021-08-31T22:28:02.793 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"
>>>> [2021-08-31T22:28:02.798 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field center: (RA,Dec) = (0.818908, 16.1438) deg."
>>>> [2021-08-31T22:28:02.801 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field center: (RA H:M:S, Dec D:M:S) = (00:03:16.538, +16:08:37.712)."
>>>> [2021-08-31T22:28:02.803 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field size: 30.3647 x 22.9561 arcminutes"
>>>> [2021-08-31T22:28:02.805 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Pixel Scale: 0.391297\""
>>>> [2021-08-31T22:28:02.808 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field rotation angle: up is 59.3579 degrees E of N"
>>>> [2021-08-31T22:28:02.810 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field parity: neg\n"
>>>> [2021-08-31T22:28:02.812 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Loading WCS from file..."
>>>> [2021-08-31T22:28:02.813 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Finished Loading WCS..."
>>>> [2021-08-31T22:28:02.815 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Solver completed after 8.67 seconds."
>>>> [2021-08-31T22:28:02.817 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Solver RA (0.81891) DEC (16.14381) Orientation (59.35789) Pixel Scale
>>>> (0.39130) Parity (neg)"
>>>> [2021-08-31T22:28:02.851 PDT INFO ][ org.kde.kstars.ekos.align] - "Solution
>>>> coordinates: RA (00h 04m 24s) DEC ( 16° 15' 51\") Telescope
>>>> Coordinates: RA (00h 04m 23s) DEC ( 16° 15' 52\")"
>>>> [2021-08-31T22:28:02.858 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Target is within 00° 00' 18\" degrees of solution coordinates."
>>>> [2021-08-31T22:28:02.871 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Target is within acceptable range. Astrometric solver is successful."
>>>>
>>>>
>>>> and here are the corresponding lines at the end of the post-flip
>>>> alignment:
>>>> [2021-09-01T02:47:35.334 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "57 stars, 44 quads selected in the image. 43 database stars, 33 database
>>>> quads required for the square search field of 0.4°. Search window at 151%
>>>> based on the number of quads. Step size at 100% of image height"
>>>> [2021-09-01T02:47:35.370 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"
>>>> [2021-09-01T02:47:35.371 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field center: (RA,Dec) = (0.864281, 16.2303) deg."
>>>> [2021-09-01T02:47:35.371 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field center: (RA H:M:S, Dec D:M:S) = (00:03:27.428, +16:13:48.980)."
>>>> [2021-09-01T02:47:35.371 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field size: 30.3658 x 22.957 arcminutes"
>>>> [2021-09-01T02:47:35.372 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Pixel Scale: 0.391312\""
>>>> [2021-09-01T02:47:35.372 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field rotation angle: up is -120.366 degrees E of N"
>>>> [2021-09-01T02:47:35.372 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Field parity: neg\n"
>>>> [2021-09-01T02:47:35.373 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Loading WCS from file..."
>>>> [2021-09-01T02:47:35.374 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Finished Loading WCS..."
>>>> [2021-09-01T02:47:35.375 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Solver completed after 3.60 seconds."
>>>> [2021-09-01T02:47:35.375 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Solver RA (0.86428) DEC (16.23027) Orientation (-120.36600) Pixel Scale
>>>> (0.39131) Parity (neg)"
>>>> [2021-09-01T02:47:35.382 PDT INFO ][ org.kde.kstars.ekos.align] - "Solution
>>>> coordinates: RA (00h 04m 34s) DEC ( 16° 21' 03\") Telescope
>>>> Coordinates: RA (00h 04m 34s) DEC ( 16° 21' 09\")"
>>>> [2021-09-01T02:47:35.382 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Target is within 00° 00' 19\" degrees of solution coordinates."
>>>> [2021-09-01T02:47:35.388 PDT INFO ][ org.kde.kstars.ekos.align] -
>>>> "Target is within acceptable range. Astrometric solver is successful."
>>>> [2021-09-01T02:47:35.389 PDT DEBG ][ org.kde.kstars.ekos.capture] -
>>>> Align State changed from "In Progress" to "Complete"
>>>>
>>>> Here are the images:
>>>>
>>>> Just before the meridian flip
>>>> [image: Screen Shot 2021-09-01 at 5.48.34 PM.png]
>>>>
>>>> just after the meridian flip
>>>> [image: Screen Shot 2021-09-01 at 5.49.24 PM.png]
>>>>
>>>> The entire log is here:
>>>>
>>>> https://drive.google.com/file/d/1T1jvXM12s7ZQKjKjwSSPU0Wl1MbacUV_/view?usp=sharing
>>>>
>>>> I'll let you know if I find something as well,
>>>> Hy
>>>>
>>>
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