Re: Astronomical Info link
thanks
yeah i think adobe flash is sadly not working on my system :(
On Thu, Jun 18, 2020 at 10:36 AM Astronut < hg2u@...> wrote: [Edited Message Follows]
Hi Brian,
That link was for one of the specific simulations (requiring adobe flash).? (I had to allow flash for that page (I am using edge browser))
Here's a generic link with all of the simulations listed:
(hovering over any of the links displays a thumbnail of the simulation visual.)
-- Brian?
Brian Valente portfolio
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Re: Astronomical Info link
When I try to access this, I get the banner across the top, and a big empty rectangle in the middle of the page where I think something was meant to load ¡ but doesn¡¯t. ?Is the site working?
Regarding learning tools and concepts¡ Starry Night is AMAZING for this. ?
Starry Night (Simulation Curriculum) is a simulation engine and they specialize in education. ?So it¡¯s a ¡°computer planetarium¡± much in the way that you might think of Stellarium or The Sky X. ?But ¡ Stellarium and The Sky X aren¡¯t ¡°simulation engines¡± and can¡¯t do a fraction of what Sky Safari can do.?
If you¡¯ve every visited a large planetarium that uses the Spitz SciDome planetarium system¡ *that* is really the Simulation Curriculum engine running the planetarium (the same engine in Starry Night).
There are loads of education modules in the software that teach all kinds of concepts. ? I¡¯ve never counted them, but I¡¯m betting there are more than 100 modules. ?The documentation that comes with it is amazing. ?
They do actually make special edition versions ¡ Starry Night Middle School, High School, and a few College editions. ?These special editions have education modules in them that are age-appropriate. ?
I use Starry Night Pro Plus to build presentations because I can set up a ¡°simulation¡± and save it as a ¡°favorite¡± (like a bookmark) and arrange these in the order that I want to use when presenting. ?Instead of PowerPoint with a bunch of static slides, I can click through a series of moving simulations. ?
Also, in Starry Night you aren¡¯t stuck on Earth. ?You can put yourself anywhere in the universe.
Clear Skies, Tim
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On Jun 18, 2020, at 1:10 PM, Astronut < hg2u@...> wrote:
Hi all,
I have had difficulty understanding some astronomical concepts in the past and usually comprehend things better visually than reading textural explanations, '
I stumbled upon this link with great simulations and explanations.
I am not affiliated at all with this site, but found it incredibly helpful to me...
Just wanted to share...
Astronut Tim
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Re: Astronomical Info link
Hi Brian,
That link was for one of the specific simulations (requiring adobe flash).? (I had to allow flash for that page (I am using edge browser))
Here's a generic link with all of the simulations listed:
(hovering over any of the links displays a thumbnail of the simulation visual.)
|
Re: Astronomical Info link
thanks tim - this just shows me a blank page. do you have some extra software installed to see this?
On Thu, Jun 18, 2020 at 10:11 AM Astronut < hg2u@...> wrote: [Edited Message Follows]
[Reason: added more info]
Hi all,
I have had difficulty understanding some astronomical concepts in the past and usually comprehend things better visually than reading textural explanations, '
I stumbled upon this link with great simulations and explanations.
I am not affiliated at all with this site, but found it incredibly helpful to me...
Just wanted to share...
Astronut Tim
P.S. There are many other simulations in the downloads link...
-- Brian?
Brian Valente portfolio
|
Hi all,
I have had difficulty understanding some astronomical concepts in the past and usually comprehend things better visually than reading textural explanations, '
I stumbled upon this link with great simulations and explanations.
I am not affiliated at all with this site, but found it incredibly helpful to me...
Just wanted to share...
Astronut Tim
P.S. There are many other simulations in the downloads link...
|
Re: glad to have found this group!
Hello TG!
Great place to be to learn and to get going with your new G11.
I have it's newer Little Brother, GM811G HD. But my payload is very tiny, just Deep Space Object imaging.
Great mounts!
--
SonnyE
(I suggest viewed in full screen)
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Re: Sawtooth pattern in DEC
Hi Arun,
Well, a 3 minute period is not the 4 minute worm period, so its not the RA worm, Oldham coupler, or gearbox.? And it's a DEC period not an RA period anyway.? ?It's also not PEC as this only corrects the RA drive.??It's a good puzzle.?
Did you drift align your polar axis before imaging?? If not, redo the drift alignment.? If your polar axis is off (and it has to be off) you'd need these DEC corrections.? It seems that PHD2's correcting, maybe overcorrecting, then has to correct again.
_____ and/or_______:
Second question is: can this be a mechanical issue, not PHD2 software per se?? To check that, grab your scope front and back and try to wiggle it on the DEC axis.? Can you move it?? If so, you should try to eliminate this mechanical hysteresis.??
There are two causes of the mechanical hysteresis: 1) the worm to ring gear spacing.? You adjust that on non SLW units by? a) use a feeler gauge to measure the space between the right side worm bearing block and the vertical plate next to it.? Write that down. b)? Try to loosen the 2 bottom hold-down bolts, and gently rotate in the worm using the left hold bolt as a pivot point.? Use the feeler gauges to determine if you got closer. But don't force the worm in too tightly.? c) retighten the mounting bolts and? d) check the worm for "Stall" or "Lags" messages on Gemini.
2) second cause of hysteresis is caused by the worm sliding along it's axis.? See if you can observe this when you rotate the scope.? If you have this worm shifting, and an SLW unit, contact the factory for advice.? ?If you don't have an SLW on this axis, see my earlier PDF on how to rectify that issue.
All the best, (and happy imaging and good health!!!)
Michael
Brian,
Here is the guidelog from yesterday. The first calibration and 12.5 minute guide run are with the scope perpendicular to the polar axis. The second calibration was done because I rotated the focuser to frame the object correctly. The second calibration was also done similarly to the first, with the scope perpendicular to the polar axis. The extended run is of the Lagoon Nebula which was pretty close to the horizon. I do see the 3 minute period oscillation in DEC in the extended run as well, similar to yesterday. It appears less prominent here I think because the RA guiding is worse with the object so low.
Arun?
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Re: Sawtooth pattern in DEC
Great -?
yes i saw the good guiding there, both axis contributing roughly equal
so that's something you'll want to watch for. If it ends up that you improve DEC considerably, you want to make sure RA is keeping up, which is why i suggested PPEC
Brian
Thanks, Brian and thanks Paul.
Yes, I always do the calibration close to the intersection of the equator and meridian because the apparent motion of stars is greatest there which would mean a good calibration. You'll see it was done at RA =14 hours and DEC=-7.8. Not exactly at the intersection, but pretty close to it!
The first thing I did when I started guiding was turn TVC to 0. However, I entirely neglected to turn on backlash compensation in PHD2 - the results were good enough without it. I assumed I had it set, but never checked! I did watch part of Bruce Waddington's excellent video yesterday and plan to finish it tonight. The first thing I looked for the shape of the RA curve when I ran GA and was happy to see that the PE seemed low.?
Brian - the reason I changed the exposure time lower was because it seemed to help with the amplitude of DEC guiding, but again, I only observed it over a short period of time.??
What I will say is this - when I checked PHD2 this morning, I was pleased to see that the last part of the guiding seemed very stable with an RMS of 0.69" over a fairly extended period of time. I'll follow your recommendations on PPEC and DEC backlash and report. I expect based on this and also Jamie's observations below that DEC backlash compensation will make a significant difference.
Thanks to all for the prompt feedback.
-- Brian?
Brian Valente portfolio
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Re: Sawtooth pattern in DEC
Thanks, Brian and thanks Paul.
Yes, I always do the calibration close to the intersection of the equator and meridian because the apparent motion of stars is greatest there which would mean a good calibration. You'll see it was done at RA =14 hours and DEC=-7.8. Not exactly at the intersection, but pretty close to it!
The first thing I did when I started guiding was turn TVC to 0. However, I entirely neglected to turn on backlash compensation in PHD2 - the results were good enough without it. I assumed I had it set, but never checked! I did watch part of Bruce Waddington's excellent video yesterday and plan to finish it tonight. The first thing I looked for the shape of the RA curve when I ran GA and was happy to see that the PE seemed low.?
Brian - the reason I changed the exposure time lower was because it seemed to help with the amplitude of DEC guiding, but again, I only observed it over a short period of time.??
What I will say is this - when I checked PHD2 this morning, I was pleased to see that the last part of the guiding seemed very stable with an RMS of 0.69" over a fairly extended period of time. I'll follow your recommendations on PPEC and DEC backlash and report. I expect based on this and also Jamie's observations below that DEC backlash compensation will make a significant difference.
Thanks to all for the prompt feedback.
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Re: Sawtooth pattern in DEC
Hi Arun
okay i think this is pretty close to a baseline guiding
Here's some observations/recommendations
- upgrade to the latest 2.6.8 PHD release
- turn on auto backlash compensation, start with an initial value of 800ms. PHD will adjust it to a more accurate amount, and continue to adjust it through the sessions to tune it as needed
- Try the PPEC algorithm for RA. set your initial value to 239.34 - that could help tune up RA a bit, although your PE looks quite low
- i see you experimenting with exposure time. looking at the difference between 1.5s and 2.5s there isn't a tremendous difference once you remove the settling (total RMS 0.81 vs 0.84)
- your calibration has more steps than i expected - the default is about 12. just confirming you used the new profile wizard, and didn't change any of those values?
?
Brian:
Another one, this time I used the GA then ran 20 mins or so with the scope perpendicular to the polar axis.
-- Brian?
Brian Valente portfolio
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Re: Sawtooth pattern in DEC
Hi Arun
Can you point me to the log where you followed the baseline guiding?
here's what i expect to see:
calibration successful run, followed by GA run, followed by 15-30 minutes interrupted guiding
anything after that is optional
just to clarify, the goal of scope position is not just perpendicular to axis, it's pointing to the intersection of celestial equator and meridian.?
Brian:
Another one, this time I used the GA then ran 20 mins or so with the scope perpendicular to the polar axis.
-- Brian?
Brian Valente portfolio
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Re: Sawtooth pattern in DEC
Arun, did you try to turn on PHD2 backlash compensation? I see in your logs that it was disabled for all the runs:
Backlash comp = disabled, pulse = 20 ms
Also, make sure to disable backlash compensation in Gemini by setting TVC to 0, so it doesn't cause an overshoot.
You may also want to watch Bruce Waddington's PHD2 presentation recorded yesterday. It starts around 2:00 mark in the video. He has some examples that look similar to your guiding log, and says it may be stiction rather than backlash (two sides of the same coin):
Regards,
? ? -Paul
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Re: Sawtooth pattern in DEC
Brian:
Another one, this time I used the GA then ran 20 mins or so with the scope perpendicular to the polar axis.
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Re: glad to have found this group!
welcome!?
it's a good group of folks, happy to answer any questions :)
I'm a very inexperienced losmandy owner, trying to learn more about my G11.
-- Brian?
Brian Valente portfolio
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Re: glad to have found this group!
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Re: glad to have found this group!
Hey OP, best you include a name in posts so we can reply to a person not just a username. ?Just forum etiquette ??
You may want to head on over to have a read of your system. ?A whole swag of good info is available there.?
--
Brendan
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Re: glad to have found this group!
Hello,
You found the right Group. And welcome to this Group. The knowledgeable people here will help you.
They finally got me on the right track with my G11G.?
HAPPY SKIES AND KERP LOOKING UP Deric.
Sent from my Galaxy Tab A
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-------- Original message --------
From: "tgdavis61 via groups.io" <tgdavis61@...>
Date: 6/17/20 8:33 PM (GMT-06:00)
Subject: [Losmandy_users_io] glad to have found this group!
I'm a very inexperienced losmandy owner, trying to learn more about my G11.
|
glad to have found this group!
I'm a very inexperienced losmandy owner, trying to learn more about my G11.
|
Re: Sawtooth pattern in DEC
Brian,
Here is the guidelog from yesterday. The first calibration and 12.5 minute guide run are with the scope perpendicular to the polar axis. The second calibration was done because I rotated the focuser to frame the object correctly. The second calibration was also done similarly to the first, with the scope perpendicular to the polar axis. The extended run is of the Lagoon Nebula which was pretty close to the horizon. I do see the 3 minute period oscillation in DEC in the extended run as well, similar to yesterday. It appears less prominent here I think because the RA guiding is worse with the object so low.
Arun?
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Re: Sawtooth pattern in DEC
actually that's why i want to see your baseline guiding.?
on one section of your guiding, it looks like pretty standard backlash that can be easily adjusted out
on another run, it looks different: there's maybe some stiction-type behavior. not sure what is the difference between the runs
Thanks, Jamie. That range is similar to what I get. I will post my baseline guiding log tonight, done with the scope perpendicular to the polar axis. A I recall, this gave me numbers close to 0.9" RMS. What was strange was the DEC oscillation was not something I've seen or noticed before.
-- Brian?
Brian Valente portfolio
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Timothy Campbell
Michael Herman
Paul Kanevsky
Jamie Amendolagine