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For the past two nights I’ve had “successful “ runs with N.I.N.A. Except with the meridian flip. I checked the boxes in the Flip profile for plate solving etc. but the results are bad. Prior to the flip my subs are sharp and centered. After the flip the stars are dashed lines on a diagonal. My advanced sequencer set up is: Unpark/Find home/Cool Camera. Next: Meridian Flip/AF after filter change. Next: Loop until < 40 degrees Next: Slew & Center/Run AF/Start Guiding. Next: Smart Exposures. Next: Park Scope/warm Camera. ‘Do I also have to add centering and plate solving to the steps above even though I checked the boxes in the Meridian Flip profile? It’s an incredible program. To be able to sleep through the night and wake up in the morning and find the scope parked and the data waiting is amazing. It would be perfect if I could find out what I’m doing incorrectly. Hank |
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There are quite a few things that can cause issues with a meridian flip, but my experience the only times meridian flip has failed has been due to it exceeding my mount limits. When my EQ6 hits limits, it stops everything in it's tracks and you can kiss the rest of the night goodbye because it only responds to home command from NINA. I alleviated this by creating a custom limits profile with EQMOD, but every once in a blue moon, I still run into it. So firstly, I would check that. Second, could you maybe screenshot some of your settings and sequencer? I'm sort of confused with how you're describing it. Most of those actions you're talking about I drop in my 'triggers' field. The way you're describing your images as 'dashed lines on a diagonal' indicates to me your scope has stopped tracking. Again, this leads me to believe it may have hit mount limits. Also, have you verified you may not have snagged cables? It's best to just do a test sequence on a target that's at meridian while you're awake, see what happens. It will likely be obvious. |
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My experience is just like Brian's. I have a long refractor and no pier on my EQ6-R so I have to set mount limits to avoid my camera from hitting the tripod legs. Funnily enough, my limit allows the camera to pass the meridian, but when it preforms a flip the mount limits stop the slew for another 20 minutes or so. I've used the "DIY meridian flip" plug-in with NINA which can really help customise the meridian flip during an imaging sequence. You can set a time to stop your imaging pre flip, and a delay to restart your imaging after the flip. Before I set these up, the mount would flip but because it hit the mount limits it would stop tracking, hence diagonal stars which would never plate solve. Alternatively, your other option would be to image two targets through the night: when the first target approaches meridian, end that target sequence and slew to another target. |
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I agree with the mount limits for first check. One time I also had this when I had not calibrated PHD2 at a suitable sky location. Things were good until the flip. Check online for best way to calibrate. Is even more critical if using an OAG. An ipolar camera that is not center calibrated can also cause this, or poor polar alignment in general. |
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| I never had issues with flips except initially some mount setting was not correct. |
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I agree with Brian on that. This is why I take limits off. But that is a lazy way out. Are you commanding a Flip after a filter change? Like Brian said, the flip is a Trigger and should be in the trigger area. That may be causing some grief. Re-center and auto-focus after the flip, yes. But like you said, those should be checked in the Meridian Flip Settings and you won't need them in your instruction list as an "after flip follow-up". My flip used to stall out until I goofed with the "Minutes after Meridian" and "Max Minutes after Meridian" settings. I changed those to 3 min and 10 min, respectively and haven't had any issues. But there is always that time that I fall asleep and the flip does not happen and I have no idea why... Hope you can solve it! |
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| What mount are you using? When I switched from an eq5 to a losmandsy g11 I was having a similar problem. The losmandsy can report which side of the pier the scope is on if you check the right box in the settings. I found until I checked that my guiding was not working after meridian flips. |
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| I have had this issue and it was connected to PhD2 not selecting a new guide star and just correcting to nowhere trying to get back to the old guide star which don't exist anymore. |
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| If you are using PHD2, dont forget to tick "Reverse DEC after meridian flip". |
5.76
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Jean Yves THIRIET: Well, except when you shouldn't. It varies by mount. There is a wizard to ensure you have the right setting under Tools. |
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| My concern has always been cable snags. We have reduced the cable snags with mounting a Pegasus unit; however, we still have a few cables that drag. In Stellarium I always select displaying the meridian, so you have an idea of where the flip will occur, and when it will occur. |
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| If using NINA it the telescope pane in imaging shows the time to meridian as well. |
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| Great topic. I need to check my limits. The meridian flip used to work flawless until recently. |
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I didn't see it mentioned above but maybe worth considering. There are two quite different ways to do the meridian flip, depending on the setting of minutes-before in NINA. If set to zero, then the idea is that NINA expects the mount to finish the last exposure while tracking THROUGH the meridian into a counterweight up position, then flip. If you set the pause-before > 0 (I recommend at least 2) then NINA will actually stop imaging before meridian, and stop tracking before then. The mount never goes into a counterweight up position. NINA just sits there (the mount just sits there) while the target passes the meridian, then NINA issues a slew according to the "after" time, and the mount will flip because the target is now on the other side. The first of these is more efficient, no time waiting. The key difference though is that the first of these requires that the mount be able to gracefully track through meridian and then flip, without hitting any limits and stopping or taking any action on its own. Often the default mount settings are NOT to go counterweight up. That's why I typically suggest people set the pause-before to 2 minutes or so, and get that working properly first. Note that if set to 2, it will be 2 plus any partial exposure you do not have time for, plus the time after (let's say that is 2). So with 4 minute exposures you could wait between 2 + 0 + 2 and 2 + 4 + 2 minutes (4 to 8). That's why I say the other is more efficient. But this is easy. FWIW. |
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It sounds to me like your mount isn't flipping when it is supposed to for some reason, but rather hitting a stop and taking exposures stuck at the stop. I had that same result that you are talking about the other night when I forgot to setup my meridian flip at all... luckily the mount safety stops performed their role and the mount sat there patiently for me to find it in the early morning when the hairs stood up on the back of my neck and I jumped out of bed in a panic. There are a few ways to skin the meridian flip cat but I found that putting it in the "Global Triggers" section makes it the easiest for me. As long as I stick it in there, my meridian flip settings are set correctly for my mount in the Settings > Imaging menu, and my safety stops are correctly configured on my mount... it works every time. When I try to put my meridian flip trigger anywhere else... well, it is hit or miss. I've attached screen shots for my basic settings that I use for every imaging session in the advanced sequencer in case it helps anyone... notes below:  When I add a target to the advanced sequencer, I place all my target prep and target imaging instructions sequentially in the target's instruction box. The initial autofocus under Target Preparation is just to get everything started. All the remaining autofocus triggers are under the imaging instructions.  I put my autofocus intervals for time/temperature in the imaging trigger section. I use calculated focus offsets so I don't need to autofocus between filter changes. I put my loop condition (until astronomical dawn) in the imaging loop condition section. Then my imaging instructions instructions are generally to take a handful of subframes in each filter, and then dither once after all the filters have cycled... in the case below, it would be 2x frames each of SII, Ha, OIII, then dither, then repeat.  My closing instructions include a parallel instruction where the guiding will stop, the camera will warm, and the scope is commanded to the park position simultaneously.Again, just offering an example of how I run it... there is more than one way to do this. But for those who are just starting out, it may offer a starting point.  Here is how I set up my meridian flips... do not use these specific settings, they will not work for you... they work for me and my setup and I have done the calculations to make it work.. notable settings that I use are "pause before meridian 0 min" because my mount can track through the meridian without hitting anything (to include safety stops... pause before meridian is for when you need your mount to stop tracking before it even hits the meridian because of collision hazard. Minutes after meridian is the soonest after the meridian passes that the flip will be directed. Max minutes after meridian is the latest the mount can continue to track past the meridian before a safety stop/pier collision occurs... calculated at 4 minutes (time) per degree of RA rotation. So all that being said, your specific settings will have to be worked out based on your configuration, mount type, etc... but try putting the meridian flip in the global trigger area. I used too many words. I would also backup the suggestion that you set up an imaging session during the day... set up your advanced sequencer with all the settings for a 60 minute imaging session, meridian flip, etc. Then go into your planetarium software, find a target (can be star... anything really) about 5 -10 minutes before the meridian, go to framing assistant, "get coordinates from planetarium", load image, add target to sequence... check the sequence... start the sequence and wait and watch. Your meridian flip should happen on schedule... if not... you can troubleshoot during daytime without losing imaging time. Change settings, reimport a new target from your planetarium and try again. |
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| Thanks for all of your suggestions. I’m going to try doing flips during the daytime and sort through the various settings. That way I can watch what happens. |
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Linwood Ferguson:Jean Yves THIRIET: Actually i think that it coould varies with driver. With EQMOD it sould be turned off with GServer turned on (but i could be wrong). I would also put the flip command in the global triggers area, and change the "Minutes After the Meridian" to a biger value, like 15 minutes. EQMOD don't alow to synk near meridian. My last advice ... change to GServer. Never had a issue. Works like a charm. |
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Linwood Ferguson:Jean Yves THIRIET: Fair point, I forget there are mounts with competing drivers out there. |
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Hi all, here is my experience with meridian flip. It is basically 2 issues interacting with each other: 1) first the NINA command - What works for me is a minimum of 10 minutes past the meridian and a maximum of 15 minutes. That way, I can image through the meridian with 5 minutes subs. NINA will allow to image up to 10 minutes in the "counterweight up" tracking as explained above. With anything less than 10 minutes, I found that I was getting "wild slews" as the reference points were sometimes on one side of the meridian and the actual centering were on the opposite side of the meridian. Using a minimum of 10 minutes seem to solve this. 2) the second issue is the mount limits. I too sometimes image with a long refractor. I am also concerned with the camera hitting the support. However if the mount settings is set to 0 degrees, then NINA will not do the flip properly. I found out that my mount - a Celestron CGEM - will need a minimum 6 degrees "approach" compensation. What that is is that the mount will go past the target and come back slowly on target. By setting the limit to 0 degrees, the mount will not be able to get on target until the target is past the meridian by the same amount ( 6° / 0.25° per minute = 24 minutes !!!). By experimenting with the mount, I found out that I can indeed set my limit in both east and west by 10° safely. Nothing will hit the support. For me, the above resolved the meridian flip issue. |
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Last night was a breakthrough night! After much experimentation, I think I’ve found the right combination in N.I.N.A. for my setup. Last night was a perfect run including a Meridian flip. I got up this morning to 116 subs (LRGB). Hank |
