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INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

Auto meridian flip in Capture module?

4 years 2 months ago
mlarsson
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Auto meridian flip in Capture module? #7649
Hi!

I'm trying to understand how to use the "meridian flip" setting in the Capture Module. I can check so it makes a meridian flip if the hour angle is above a certain value. What is the value I am to put here? The maximum allowed angle for the capture duration, or what? I've not been able to find a description that I can use...

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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4 years 2 months ago
knro
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Auto meridian flip in Capture module? #7652
Please check the capture module documentation . If it's not clear, please let me know.

Jasem Mutlaq
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4 years 2 months ago 4 years 2 months ago by mlarsson.
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Auto meridian flip in Capture module? #7874
Hi!

I think what I don't understand, is how I calculate the hour angle limit. I know the limits for the scope, that is, how many degrees east of the mount it can move. But how do I transform that to an hour angle limit?

I guess I simply could calculate the time when the object crosses the meridian and use 0 as the hour angle limit - but then again, how do I find that?

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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4 years 2 months ago
mlarsson
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Auto meridian flip in Capture module? #7888
Hi!

Yes, well, I guess I am just confused here. Sorry for producing confusing posts too. But I simply cannot make the mount do a meridian flip with the capture module. So: is it supported for the Losmandy Gemini? I note that the instructions say something about if the mount supports it, and maybe the driver for the Gemini lacks this function?

Attached is log files (verbose output) for an attempt to produce a meridian flip

Magnus


C8, Losmandy G11, Canon 1000D astromodified.
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4 years 2 months ago 4 years 2 months ago by knro.
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Auto meridian flip in Capture module? #7897
IF your mount passes the meridian, and then you ask it to go to the same location it is currently tracking, does it perform a meridian flip or not?


Jasem Mutlaq
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4 years 2 months ago
mlarsson
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Auto meridian flip in Capture module? #7915
Hi!

Ok, I've been experimenting. Today, when the star crosses the meridian and exceeds the hour angle, the capture module says it should do a meridian flip. Then immediately (7 seconds later) it says it is completed and takes a new picture. The scope does not move.

I've attached log files below.

Magnus


C8, Losmandy G11, Canon 1000D astromodified.
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4 years 2 months ago
knro
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Auto meridian flip in Capture module? #7917
Magnus,

Please read this Losmandy Manual . Page 33, Section 3.3.4

However, this does not work with most control software that uses only the Meade command set without Gemini’s extensions. For these programs, the
only solution is to GoTo an object that is past the western safety limit to force the meridian flip, and then go back to the object of interest.

To solve this problem, Gemini now allows you to set a “GoTo Limit” to define a point past which Gemini will always GoTo the object so that the telescope tube is on the east side of the mount. Gemini will allow the mount to track past this point, but will not GoTo any object west of this point without a meridian flip, if needed, to put the telescope tube on the east side of the mount. Refer to section 5.3.10.2.6 for a description of the “Set GoTo” limit command


And then in 5.3.10.2.6

The “Set GoTo” command allows you to specify an angle relative to the CWD position which will affect meridian flips during a GoTo operation. A GoTo command to any object that is west of this angle will cause Gemini to do a meridian flip, if needed, to ensure that the telescope tube is on the east side of the mount when pointing to the object.

For example, setting the GoTo limit to 95 degrees means that a GoTo command to any object 5 degrees or further west of the meridian will cause Gemini to point to this object with the telescope tube on the east side of the mount (doing a meridian flip if needed). The telescope will still track an object past this point if the tube is on the west side of the mount, but once an object has passed the GoTo limit, a subsequent GoTo command to this object will force a meridian flip.
A value of 90 sets the GoTo limit to the meridian itself; meaning that a GoTo command to any object west of the meridian will force the telescope to the east side of the mount.


So if you set your Set GoTo to 95 for example, you must be the Ekos Meridian Flip HA to be issues after 95 degrees is passed. 1 Hour = 15 Degrees. For 5 degrees = 0.33 hours. To be safe, set the Ekos HA to 0.35 or 0.4 even. When Ekos issues a GOTO when the mount HA is 0.4 hours (6 degrees west of the meridian), the mount should flip because it is passed the Set GoTo limit of 5 degrees passed the meridian.

I hope this clears it.

Jasem Mutlaq
Support INDI & Ekos; Get StellarMate Astrophotography Gadget.
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4 years 2 months ago 4 years 2 months ago by mlarsson. Reason: Update.
mlarsson
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Auto meridian flip in Capture module? #7919
Hi!

Great!! I hadn't noticed that in the manual.... You really are amazingly helpful, Jasem!!

So: I set the SetGoTo to 90, and then run a seris of exposures on a star crossing the meridian. And now it works! It initiates a meridian flip!

Hrm. Update: it is a bit funny. I'm doing a series of experiments, targeting a spot precisely before the meridian and running a capture to get a meridian flip. At times it waits until the picture is taken, but not always. Mostly, it does the flip in the middle of an exposure. And in the session here, with the logs below, it did the meridian flip in the middle of the exposure, and then after the exposure, reported in the capture window again that is iniitated a meridian flip - so twice for the same session. The scope moved the first, but not the second time (as the flip was already made).

In either case: it starts the next exposure directly, without waiting for the flip to be finished.

Is there anything going on here that I can do something with?

Magnus


C8, Losmandy G11, Canon 1000D astromodified.
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1 year 5 months ago
calberts
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Auto meridian flip in Capture module? #34326
Hoi Mlarson, Jasem

Did you already fixed this issue, I am running against an simalar issue, See tread indilib.org/forum/development/1406-drive...html?start=468#34273
I discovered de following in relation to my mount the OnStep. I can define the degrees when the flip starts in my mount. For example I define 5 minutes passing the meridian.
I discovered for my situation that the HA must be lower than the 5 minutes. If i define HA on 0.00 i see that it waits to finish the exposure and after that Ekos start the Flip. However i am running in a situation that the flip is not finished will ekos times out, does a retry and initiate the next capture which cause the still running flip to stop. :-( My slew speed is to low if you compair that with the video of Jasem. I think we need extra setting beside the HA which define the time a flips need and that dat differents between mounts. I am also aware that in worse case scenarios for example my max exposure with this setting is 5 minutes is the exposure start starts 1 second before HA 0.0.0

I see here some more development needed and this function is essential for astrophotographers, i am move from the FS2 to OnStep because FS2 has no flip and park and EKOS looks the the ultime program to run unattained for photography , i am not programmer so iam relay on the programmers in the forum.

For me it's not clear how we get attention to this and are we the only ones having this problem

Chris
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1 year 5 months ago
calberts
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Auto meridian flip in Capture module? #34486
Hoi there will be a update soon in Kstars zie link indilib.org/forum/development/1406-drive...html?start=468#34273

Chris

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