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Re: Spikes!
The symptoms you describe make me think you have a slight imbalance to the West.? It is easy to test, if you disconnect the motor coupling then use your thumb to turn the worm.? With my G11S, if there is only a slight imbalance the mount stutters all over the place when turning in the direction where the weight is.? In the other direction it turns smoothly.? This is why Michael advised to balance it precisely then counterbalance it East.? I wonder if some grease would help, my worm is bone dry.? I have some teflon superlube in a spray can but I have the feeling that I bought the wrong thing.? Still I'm surprised this happens.
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Re: Spikes!
Ok, so it looks like it will be clear tonight. I'm looking at this now. I don't understand why big step sizes are a problem. The only recommendation I see in the PhD docs mentions number of steps,p not size. Why would a larger size cause a problem? Wouldn't a larger size step give better results as long as the total number of steps is the right amount?
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Re: Nice discussions leading toward perfection...
I am using an ASIair Pro and seem unable to get stars in focus. I know a basic thing right. When I do my guiding in the AAP is all over the place. I think it is due to poor atmosphere conditions but I have had so many ups and downs with the whole guiding concept that I am just going slow and trying to incrementally sneak up on it. ? Tom --- jjkmetz54@... wrote: From: "John Kmetz" <jjkmetz54@...> To: [email protected] Subject: Re: [Losmandy_users_io] Nice discussions leading toward perfection... Date: Wed, 07 Apr 2021 08:44:58 -0700 On Wed, Apr 7, 2021 at 09:44 AM, Tom & Barbara Coverdale wrote: Thanks John! That was generally what I thought but I was wondering if there was a focal length above which guiding became a necessity. I enjoy the educational value of this thread. I plan to keep trying to get my guiding working. Thanks again. TomTom, I also have a 102mm scope with a 0.7X focal reducer (500mm FL) and I always use PHD2 to optimize guiding. The FL of your main scope times 0.2-0.25 is about where the focal length of your guide scope should be. But it sounds like you may already have one. What are your PHD2 issues? Connection or operation? John |
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Re: G8 DEC axis backlash, fixing, questions
You do not have to cycle the power. you can adjust it on the fly too On Wed, Apr 7, 2021 at 5:56 PM Jim Waters <jimwaters@...> wrote: One more question.? When I set TVC do I need to cycle the power before it takes?effect? --
Brian? Brian Valente portfolio |
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Re: G8 DEC axis backlash, fixing, questions
I normally get around 1000 for dec backlash. Phd2 manages it very well. As long as I have pa below 5 arc min I usually get dec rms well below 1. If I try and remove the backlash by tighting the worm the backlash does improve, but at the expense of rms and good images.?
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Re: G8 DEC axis backlash, fixing, questions
>>>
I always assumed DEC backlash was somewhat consistent.? This make it harder to correct. PHD's auto backlash compensation does that for you, which is why you want to use that approach On Wed, Apr 7, 2021 at 11:02 AM Jim Waters <jimwaters@...> wrote: I always assumed DEC backlash was somewhat consistent.? This make it harder to correct. --
Brian? Brian Valente portfolio |
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Re: G8 DEC axis backlash, fixing, questions
You can - sort of you can measure it by summing the pulse guides until it reverses direction But it won't be consistent for comparison or understanding over time. Backlash changes through the night depending on altitude, side of pier, shifting gear, etc. so it's an approximation You could?measure it (and repeat measure it) guiding from a fixed point in the sky like intersection of meridian/celestial equator? On Wed, Apr 7, 2021 at 9:17 AM Jim Waters <jimwaters@...> wrote: Can you determine backlash from the logs or do you need to run Guiding Assistant? --
Brian? Brian Valente portfolio |
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Re: Pixinsight Tutorials?
PS funny you asked this, i was literally processing an image with WBPP just now This is a couple hours on eta carinae nebula, just WBPP and some curves. so even the basic processing works pretty well. On Wed, Apr 7, 2021 at 8:51 AM Scott Popjes via <imagemover=[email protected]> wrote: I am taking the plunge into learning Pixinsight.? ?Anyone have any recommendations for good tutorials on YouTube? --
Brian? Brian Valente portfolio |
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Re: Pixinsight Tutorials?
Hi Scott My suggestion is starting with WBPP (weighting batch preprocessing script) which can get you from data to an RGB image in the fastest way possible while still learning an approach that will work for you as you get better at PI There are four main options: FREE - light vortex astronomy has some good pages. they are quite outdated but relatively easy to follow?? - youtube - tons of stuff on youtube. not a huge fan because it's a bit piecemeal but there's a lot of content there PAID - Rogelio has a book on learning PI. it's popular. more of a reference than a tutorial - warren keller has ip4ap subscription. tons of content, imo more of a reference? - adam block has fundamentals? which are great and very thorough but quite detailed and long Personally, i really like starting with Adam Block's FastTrack. it's like $40 and uses WBPP to go from zero to finished pic inside a day. it's not everything, but a great place to start On Wed, Apr 7, 2021 at 8:51 AM Scott Popjes via <imagemover=[email protected]> wrote: I am taking the plunge into learning Pixinsight.? ?Anyone have any recommendations for good tutorials on YouTube? --
Brian? Brian Valente portfolio |
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Re: Nice discussions leading toward perfection...
On Wed, Apr 7, 2021 at 09:44 AM, Tom & Barbara Coverdale wrote:
Thanks John! That was generally what I thought but I was wondering if there was a focal length above which guiding became a necessity. I enjoy the educational value of this thread. I plan to keep trying to get my guiding working. Thanks again. TomTom, I also have a 102mm scope with a 0.7X focal reducer (500mm FL) and I always use PHD2 to optimize guiding. The FL of your main scope times 0.2-0.25 is about where the focal length of your guide scope should be. But it sounds like you may already have one. What are your PHD2 issues? Connection or operation? John |
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Re: Nice discussions leading toward perfection...
Thanks John! That was generally what I thought but I was wondering if there was a focal length above which guiding became a necessity. I enjoy the educational value of this thread. I plan to keep trying to get my guiding working. Thanks again. Tom --- jjkmetz54@... wrote: From: "John Kmetz" <jjkmetz54@...> To: [email protected] Subject: Re: [Losmandy_users_io] Nice discussions leading toward perfection... Date: Tue, 06 Apr 2021 23:01:51 -0700 On Tue, Apr 6, 2021 at 10:16 PM, Tom & Barbara Coverdale wrote: Mike et al,Tom, Most people use PHD2 or another app for correcting their guiding unless they are very happy with the tracking of their mount. Super steady tracking allows for sharper and rounder stars and can be used for much longer exposure times for your subframes. More advanced astroimagers are willing to pay a premium for the best possible tracking and are willing to buy mounts which can approach $10K or even much more. The tech discussions you see here are mostly centered around squeezing the maximum performance out of the moderately priced Losmandy mounts.? So you will see much about fine tuning the mechanical drive train, or using various software settings to gain the most advantage. The longer the focal length of your scope and the smaller the arcsecond diameter of the astronomical target of interest, the more accurate the guiding needs to be.? If you are happy with your images, then you are good. The tech talk from all the scientific and engineering folks is more an expression of interest in the topic, and their willingness to apply their talents to maximizing operation. It can be overwhelming and you don't really need to absorb it all to enjoy the basic use of your mount. John
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Re: G8 DEC axis backlash, fixing, questions
On 4/6/2021 11:51 PM, Brian Valente wrote:
you can try TVC 10. if it's working well, you should see backlash amount decrease (but not be eliminated)FWIW..... I find that my GM811 DEC backlash as reported by PHD2 varies between something less than 200mS and about 1800mS depending on where I am pointing and possibly other unknown variables. Typical is around 1200mS. I can set TVC to a non-zero value and reduce the PHD reported backlash nicely. In my case, TVC=10 seems to be a good number. But that runs the risk of reducing the overall backlash to (or below) zero depending on pointing location. If backlash approaches zero, the system can oscillate. This is especially noticeable at the start of a new session or after a slew because PHD2 may be attempting to compensate for more backlash than is currently present. I have decided to use TVC=0 as long as the reported DEC backlash is less than 2000mS. PHD2 can easily compensate for that amount of backlash and the only observable effect is that on DEC reversals PHD2 appears to wait for the duration of the applied backlash compensation before beginning a new exposure. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com |
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Re: G8 DEC axis backlash, fixing, questions
Well in my case the more you tighten the clutch, the tighter the worm mesh gets.? So either the ring gear gets pulled down a little with a tighter clutch, or at low clutch pressure, the upper bearing is not sufficiently preloaded, and the pressure from the worm pushes the ring gear / axis away.? The way to check is to replace the clutch pad with some imcompressible material and then measure the gap between the setting circle and main body with feeler gauges while tightening the axis.? But I didn't want to bother going thru all the trouble of having the clean and then regrease the shaft to take out the clutch pad.
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Re: G8 DEC axis backlash, fixing, questions
On Tue, Apr 6, 2021 at 04:09 PM, Henk Aling wrote:
Does this mean that the back-off screw is meant to keep the worm from riding up the ring gear because if it does, the assembly wobbles?? That would be disappointing.It's the preload from the regular screw (with spring) that keeps the worm from riding up. I tried putting an o-ring underneath the allen head for the block bolts, but it didn't make a difference. |
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Re: Nice discussions leading toward perfection...
On Tue, Apr 6, 2021 at 10:16 PM, Tom & Barbara Coverdale wrote:
Mike et al,Tom, Most people use PHD2 or another app for correcting their guiding unless they are very happy with the tracking of their mount. Super steady tracking allows for sharper and rounder stars and can be used for much longer exposure times for your subframes. More advanced astroimagers are willing to pay a premium for the best possible tracking and are willing to buy mounts which can approach $10K or even much more. The tech discussions you see here are mostly centered around squeezing the maximum performance out of the moderately priced Losmandy mounts.? So you will see much about fine tuning the mechanical drive train, or using various software settings to gain the most advantage. The longer the focal length of your scope and the smaller the arcsecond diameter of the astronomical target of interest, the more accurate the guiding needs to be.? If you are happy with your images, then you are good. The tech talk from all the scientific and engineering folks is more an expression of interest in the topic, and their willingness to apply their talents to maximizing operation. It can be overwhelming and you don't really need to absorb it all to enjoy the basic use of your mount. John
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