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Re: G11 guide speed
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Re: Bright Star disappeared from list despite being well above horizon
Sonny Edmonds
Hi John, and welcome to the group!
I also am a new owner of a GM811G (HD tripod). (February 4, 2020) Mine does have the G811 as a choice in the hand controller. But the default is for a G11. For me, if the G11 is chosen, it throws off the GM811G mount. I haven't intentionally chosen it, but have had it change mounts, probably after doing a "Factory Reset". It only happened once, but once was enough that I like to do the Quick start menu to make sure I'm on the right path to begin with, as a review. And the Quick Start winds up at a Cold Start anyway. Tanya walks us through in this easy to follow video. I've done it a few times just to be sure any goofs I may have caused were wiped out. But as I got rid of the bad habits from my old Celestron mount, things have gotten much better. I would suggest you try a factory reset, and see if it helps. I don't see how it could hurt anything. You will have to go from scratch through the Quick Start Menu, check the location, mount type, time and date... just the routine. But see if the (push)menu-(push)mount-(push)type doesn't show 7 options. Custom Mount, GM8, G811, G-11, GMT, HGM-200/M250, and lastly Titan. I'm finding the more I unlearn from my Celestron mount, the better and faster I'm becoming with my new GM811G. I move mine out, and back in, every night. CFO rules, she wants it stored in the house. (She never let me bring my Harley in the house.) I just smile and say "Yes Dear." I just love my new Losmandy Mount! (I hate the clouds that are punishing me, but love the Mount) -- SonnyE (I suggest viewed in full screen) |
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Re: Bright Star disappeared from list despite being well above horizon
Hi John welcome?to the losmandy side of things :)? Usually when this happens it's because there's a mis-configuration in date/time and/or location. Being low on the horizon, it wouldn't take much, maybe an hour or two difference. One way you can figure out where it thinks it's pointing is by using a planetarium hooked up to your mount, such as Stellarium () which supports ascom connection to losmandy.? PS i'm curious about astroitalian moniker? On Sun, Apr 19, 2020 at 4:22 PM <astroitalian@...> wrote: Hello All, --
Brian? Brian Valente portfolio |
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Bright Star disappeared from list despite being well above horizon
Hello All,
I'm new to this group, having just recently purchased a GM811G mount to replace a Celestron CGX, which had served me well, but I wanted to upgrade.? I really appreciate the quality of the Losmandy mount.? I had to install a wavy washer to loosen up the RA axis, and so I was out last night doing some visual for the first time in 6 months with my Tele Vue 127is, as I'm usually doing AP, just to test it out and everything went smoothly.? I did modeling for both east and west, and pointing accuracy was good.? But at the end of my session, I wanted to go back to Sirius just once more to check pointing, and it was no longer on my Bright Star list, despite still being at least 20-25¡ã above the western horizon and plainly visible.? I tried slewing to another object to see if it might reappear on the list, and it did not.? Being as I'm going to be wanting to image some objects that will be low on my southern horizon, that concerned me a bit.? Any help would be appreciated. And while I'm at it, another question.? As I recall when I set up about 2 months ago, the GM811G was not one of the mount choices, so I believe I chose G11 as my mount.? Was that the correct choice, or should I have chosen the GM8? Thank you, and I look forward to perusing the threads here.? I'm sure it will be a great learning experience! John |
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Re: Side-of-pier issue
¿ªÔÆÌåÓýHi! Let me take SW to NW as an example instead: I slew from RR Tau to GM Cam. This is from: 05 39 30.51??? +26 22 27.0 To: 03 59 10.08??? +58 01 07.7 At around 10pm (at my location, but that should be same for you,
shouldn't it?), that means slewing from somewhere roughly SW to
more NW - and in doing this slew, the mount shifts side-of-pier -
roughly as it crosses 270 degrees azimuth. Roughly, I stay at an altitude of around 30 degree, and slew on
the western side of the sky. Then the slew is both in RA and Dec.
Does that help? Simulate on for instance CdC, and I think you will see what I
mean. And I'm at latitude 55 degrees North. Magnus
Den 2020-04-19 kl. 18:28, skrev Brian
Valente:
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Re: Side-of-pier issue
I generally understand your somewhat unusual case What i don't understand is this: when I want to go from NE to SE, that is a slew in DEC for me. you're saying slew in RA, and I don't see how i would get to SE just by moving RA? On Sun, Apr 19, 2020 at 9:19 AM Magnus Larsson <magnus@...> wrote:
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Brian? Brian Valente portfolio |
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Re: Side-of-pier issue
¿ªÔÆÌåÓýHi! No, it is a slew in RA - I'm doing it with the same declination,
just slewing in RA, to test. And right, no crossing the meridian.
But physically, crossing the 90 degree azimuth line, the
counterweight bar crosses to the other side of the mount - hence
shift of side-of-pier, in a very literal sense. Yes, it impacts my guiding since when the mount reports shift of
side-of-pier, PHD2 swaps direction of RA guiding. But since no
direction of the guidecam or otherwise in the mount has happended,
this means that RA now escalates errors, rather than works against
them - hence escalating run away scope. In essence, PHD2 interprets shift of side-of-pier as a meridian
flip. But this is not the only case when it occurs nor when the G2
reports it. It took me quite a while to see this... And I guess this is not
what would be problematic in regular AP, when you find a target,
maybe calibrate, and then track for hours. Then there is a
meridian flip, RA shifts, and back to tracking. It happens here
because I slew from target to target, imaging 20-25 different
targets with just one or two subs of each, but I need guiding
because I do some 5 mins exposures and I get too much drift if no
guiding. I have my complex sequence set up so it goes from lower
altitude to higher, picking stars before they are too low,
basically, and then waiting for some to rise some more (manually
sorted). It means that it will start out on the west side, going
in sort of zig-zag motion from RR Tau to GM Cam, to YY Aur, to U
Gem and so on. Do you see it now? Or what can I send or describe that makes it more clear? Best, Magnus
Den 2020-04-19 kl. 17:48, skrev Brian
Valente:
Hi Magnus |
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Re: Side-of-pier issue
Hi Magnus
No, it doesn't really make sense to me.? if i go from NE to SE, this is just a DEC move, i'm not crossing the meridian. So why would it report side of pier change? confused abou tthis i can slew back and forth, but it sounds like your issue is how is guiding impacted, correct? So i would assume you need some guiding to take place in this situation to see how it impacts. |
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Re: Guiding and clutch tightness
ah okay - then yeah it would make sense for 2x 7lb. turns out that's exactly what i have for my Sky90 right now On Sun, Apr 19, 2020 at 7:48 AM Arun Hegde <arun.k.hegde@...> wrote: Hi Brian, --
Brian? Brian Valente portfolio |
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Re: Guiding and clutch tightness
Arun Hegde
Hi Brian,
I actually tried pushing the 11lb weight all the way up and adding a 7lb weight, but the combination is too heavy to balance. I have a Stellarvue SVX080T, filter wheel and ZWO ASI1600MM PRO camera. The 11lb weight is about 10.5 inches from the rotational axis of the mount. I will try to take a picture and send it the next time I set up (probably tonight). |
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Re: Side-of-pier issue
Sonny Edmonds
Hi Magnus!
I'm afraid this is not only above my pay grade as you put it, but probably above my present intellect. However, I wanted you to know I am following this in the hope I can see it to a solution. It's in my blood to be a troubleshooter, so I take a keen view. But I wanted to let you know I'm watching this. Just setting on the sidelines, in case it crops up for me someday. -- SonnyE (I suggest viewed in full screen) |
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Re: Side-of-pier issue
¿ªÔÆÌåÓýHi! It might be that there is no issue, and I have messed things up.
But it might also be that my use case is somewhat rare, which is a
reason this has not been surfaced before. THe thinking around this
is really a bit above my paygrade. I can follow the logic but not
assess it. So my understanding is: There are two cases when
side-of-pier really shifts: in a meridian flip, that is, shifting
side of pier for an object traversing the meridian. Or, as in my
case, when slewing from SW to NW or the other way around. These
cases are very different in a guiding sense. For the meridian
flip, RA should be reversed. For the second case, nothing should
happen. So: what I think would be good is to hear if other's G2s also
report a shift in side-of-pier when slewing from SW to NW and
back, and from SE to NE and back. For instance, following this
sequence: 1. South 2. SW 3. NW 4. SW 5. NW 6. N (meridian flip) 7. NE 8. SE 9 NE 10. SE 11. S (meridian flip) In this sequence, a "wrong" side-of-pier shift should be reported
in step 2-3, 3-4, 4-5, 7-8, 8-9, 9-10, and a "correct"
side-of-pier shift in steps 5-6 and 10-11. Does that make sense? Magnus
Den 2020-04-19 kl. 01:15, skrev Brian
Valente:
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Re: Side-of-pier issue
Magnus can you clarify what exactly is the test you want to verify? I've been following your PHD thread and looked at the indi thread. I'm not convinced it's a gemini firmware issue, since i've really never heard this before, but i'm willing to test it out On Sat, Apr 18, 2020 at 10:35 AM Magnus Larsson <magnus@...> wrote:
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Brian? Brian Valente portfolio |
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Re: Side-of-pier issue
¿ªÔÆÌåÓýHi Sonny!! Well, I could easily "fix" it by re-calibrating in PHD2. But that
is not a good solution, as this problem happens several times in
the midst of my 20-25 jobs schedule, as the mount works through
lower altitudes to higher, in the process slewing hither and
dither... And: automated... I cannot have it recalibrate after
every slew, as that would almost double the time for the whole
process. Thing seems to be, that side-of-pier is reported by Gemini
whenever the side-of-pier shifts, physically. But that messes
things up and causes this issue. PHD2 cannot differentiate between
a side-of-pier-shift because of a meridian flip and just slewing
from SW to NW.... But the Gemini can differentiate these between
these cases. And, as I understand it, should ONLY report
side-of-pier when it is a meridian flip case. As I understand it
from the PHD and Indo fora. But I might be wrong - it has happened
before.... I don't know how other mounts manage this, and I am way out of my
depth when we talk about what the codes the Gemini sends to my
Indi-server really are (serial commands....). But that seems to be
where this happens. And: what would really be helpful, is if someone else can verify
the behavior. To see if there is something with just my mount, or
really in the Gemini code.
Best, Magnus
Den 2020-04-18 kl. 18:00, skrev Sonny
Edmonds:
Hi Magnus! |
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Re: Guiding and clutch tightness
Sonny Edmonds
Arun,
That gives me food for thought. My PHD2 graph has some rhythmic jags to it. Particularly in Dec (red trace).? I tend to not worry about my PHD2 graph as long as my images are good, and I'm getting nice round and pinpoint stars. But maybe I am a little tight on my clutches... I think I will try a little tenderness. After all, I can go back to a little snugger, if looser doesn't pan out. -- SonnyE (I suggest viewed in full screen) |
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Re: Guiding and clutch tightness
Hi Arun good to hear your progress regarding your weights, do you have a picture of your setup? maybe you can just add a 7lb and push the 11lb all the way up? regarding PPEC - that algorithm is really just hysteresis, plus some watching of your periodic error and issuing corrections in anticipation of periodic movement. it's really quite good, but it does take a few worm cycles for it to learn and improve. you can also adjust the predictive gain really low, so that part contributes relatively little, while the main guiding is hysteresis On Sat, Apr 18, 2020 at 7:41 AM Arun Hegde <arun.k.hegde@...> wrote: So I followed one of the tips in one of the threads and loosened the RA clutch. Had it very tight, but have now learned that that is not advisable. So I tightened it just enough so the (balanced) scope wouldn't move to gentle pressure. The improvement was quite noticeable. Where in the past RA was worse than DEC in RMS and seemed to have somewhat large period (though low amplitude) oscillations, the moves now seem much more random, as they should be, and my RMS in RA is now only slightly higher than DEC. And it held this over many hours.? --
Brian? Brian Valente portfolio |
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Re: Side-of-pier issue
Sonny Edmonds
Hi Magnus!
What you are describing is, to me, an anomaly in PHD2 itself, for my lack of a better way to describe it. What I learned to do (this was with my old mount) was to close PHD2. And I mean just slam the door on it. Then open it again to a fresh unadjusted program, and start it up again after the change. Let it automatically select a guide star, and give it time to settle in and stabilize. After that, it would go on guiding. It was another of my "Sonny's Work Rounds" to keep me in this crazy way of connecting my yard with outer space. Some things I do make no sense to others, but they work. -- SonnyE (I suggest viewed in full screen) |
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Guiding and clutch tightness
Arun Hegde
So I followed one of the tips in one of the threads and loosened the RA clutch. Had it very tight, but have now learned that that is not advisable. So I tightened it just enough so the (balanced) scope wouldn't move to gentle pressure. The improvement was quite noticeable. Where in the past RA was worse than DEC in RMS and seemed to have somewhat large period (though low amplitude) oscillations, the moves now seem much more random, as they should be, and my RMS in RA is now only slightly higher than DEC. And it held this over many hours.?
Now I will look to replace my one 11 lb weight with two 7 lb weights placed closer and see if that helps. I would have to do a calculation to see if it reduces the overall moment of inertia. I also experimented with the PPEC algorithm for guiding in RA, but hysteresis seemed much better for my mount. |