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Re: DEC delay in reversal
Suresh Mohan
I just now re meshed the dec gear box . Let me test in the evening
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Suresh
On 04-Mar-2018, at 9:35 AM, Suresh Mohan Neelmegh <drsureshmohan@...> wrote:
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Re: PemPro Polar Alignment differs East to West
Suresh Mohan
To overcome this problem i use a star at 45 degrees or slightly above as I live on a hot sea coast where atmosphere sizzles . It might take a little longer but it gets accurate ( however I use a refractor )
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On 04-Mar-2018, at 2:01 AM, 'Joseph Zeglinski' J.Zeglinski@... [ap-gto] <ap-gto@...> wrote:
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Re: DEC delay in reversal
Suresh Mohan
On Phd with this gear box for backlash I got a message saying I should guide only in one direction ; while calibrating it goes north quite easily and does not move south for the guiding speed at 1 x I think
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Suresh
On 04-Mar-2018, at 9:30 AM, Suresh Mohan Neelmegh <drsureshmohan@...> wrote:
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Re: DEC delay in reversal
Suresh Mohan
Matthew ,
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I doubt a collision would do anything ; mine is the worst as I travel often Indi China border , im sure though its extremely well packed , the boxes are thrown from 2-3 feet ( maybe I’m exaggerating ) by cargo people . Roland I tightened the worm shaft bearing retention screw ; still the same problem . Two nights ago I swapped the gear boxes as I found the original DEC worm give a better RAW PE ; i noticed that RA gear box flat spring that holds the two adjustment screws having less tension as compared to DEC . I think I should go back ? Suresh
On 04-Mar-2018, at 8:19 AM, Matthew Hughes matthughes77@... [ap-gto] <ap-gto@...> wrote:
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Re: DEC delay in reversal
Hi Andy,
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Yes you did not say that. My bad. Just has the collision and put two and two together without proper analysis. Matt
On 4 Mar 2018, at 13:17, Andy Galasso andy.galasso@... [ap-gto] <ap-gto@...> wrote:
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Re: DEC delay in reversal
Andy Galasso
>> Matt wrote: >> Andy from PHD says that it is a delayed reaction from the DEC axis then overcorrecting. Matt, sorry for the apparent misunderstanding but I did not say that! Based on what you showed me I don't even think you can definitively say the guiding problem is caused by the mount until you run some experiments to rule out various things, like for example a problem with the camera driver buffering frames. I have seen cases where a faulty camera driver buffered data and that resulted in oscillation in guiding. Andy
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Re: DEC delay in reversal
Hi Rolando, I have the same issue, I think. Last night I had an abrupt pier collision. I wont go into too much detail but is was my fault. https://groups.yahoo.com/neo/groups/ap-gto/files/Dec%20guiding%20issue/ Andy from PHD says that it is a delayed reaction from the DEC axis then overcorrecting. It starts off ok for about 5 or 6 samples then does this repeatable pattern. Also in the same folder there is a picture of the small round access hole I think you were talking about? Some help would be appreciated. I hope I haven't done too much damage. RA axis looks fine. Blue encoder lights are still on. Any other fault finding tips would be appreciated. Yours in "stress" Matt
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Re: APPM and Pinpoint
W Hilmo
I have the image scale set correctly in the settings in APPM. When the dialog comes up with the Solve button, it correctly says 1.62 on my screen. I was very careful to make sure that all of the settings were correct.
That said, there is something strange going on. I switched APPM to use TheSkyX for solving and it solved all of my test images very quickly (never more than 5 seconds). When I switched back to Pinpoint, APPM was able to solve it through Pinpoint, and it still can and I can’t reproduce the failure anymore. I have no idea what changed, but now it works fine. I even switched to some images with a very different image scale and it solves those fine (with the appropriate changes to sigma and max magnitude). Thanks for taking a look, though. My feature request, if possible, would be to get APPM’s test image link to log the same kinds of details that Visual Pinpoint does (I assume that Visual Pinpoint is using the same API to the solving engine that is available to APPM). In particular, reporting the number of stars detected and the number of catalog stars would be useful, since those are the main settings that you would adjust for a given scope/camera combination. Thanks again, -Wade From: ap-gto@... [mailto:ap-gto@...] Sent: Saturday, March 3, 2018 3:40 PM To: ap-gto@... Subject: RE: [ap-gto] APPM and Pinpoint Wade, That is very odd as APPM plate solved almost instantly. I'll send you a screen shot. (BTW, there is a typo in theThe problem may be that the image scale is set wrong in APPM. The image doesn't appear to have an image scale value so APPM will use whatever value was set in APPM. If that image scale is not within the tolerance the plate solve won't work. (BTW, the plate scale is about 1.62 arc-sec/pixel for your image). Best regards, -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message----- [Non-text portions of this message have been removed]
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Re: APPM and Pinpoint
Wade,
That is very odd as APPM plate solved almost instantly. I'll send you a screen shot. (BTW, there is a typo in theThe problem may be that the image scale is set wrong in APPM. The image doesn't appear to have an image scale value so APPM will use whatever value was set in APPM. If that image scale is not within the tolerance the plate solve won't work. (BTW, the plate scale is about 1.62 arc-sec/pixel for your image). Best regards, -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message-----
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Re: PemPro Polar Alignment differs East to West
Ray, why we are on the topic of PEMPro, I wanted to mention another issue I had last night. I kept getting an error lastI think you should check that the .Net Framework 4.x is up to date. That error can only happen when creating a normal 32-bit Bitmap in the .Net Framework. Also make sure you have binning set to 1 on step 2 just in case a binned image might be causing a problem. -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message-----
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Re: PemPro Polar Alignment differs East to West
Joe Zeglinski
Andrew,
I don’t think it matters which pier side you start from.
As it is written now, PemPro does a continuous run, with no way of
splitting it into two parts, so that we could do a half on each side, and merge
the two sample files together to make say, a total 6 cycle file of raw data.
Ideally, the span of cycles should be equal on both
sides, since when you are finally CCD imaging, the BEST photos result from a
“span” of exposures, taken either side of the PM. You would be taking your
Blue exposures before the prime meridian, and the Red ones after, where the blue
in the sky diffusion tails off in the denser air. Thus, the best imaging is
achieved through “planning exposures”, that span the PM.
Would be nice if the PEC curve an average matching both
sides, as well. Then, your curve accounts not only for the somewhat
stochastic pattern from the small spur gears inside the gearbox, it also
includes a span of the worm and worm wheel contact irregularities, in the
collected curve. End result is that it would account for more than just
the gearbox effect, in the generated PEC curve.
However, another problem would arise if I were to do a
PemPro run, “right through” the meridian.
If the scope is “TOO perfectly” balanced, there may be some very minor worm
tooth “gear play” during the transition ... causing a slight lag as the
mount passes PM. Or, there could be a “loading change” on the worm/worm
wheel, and the gears in the box, if the OTA is (purposely) slightly
biased, off-balance. Either one could (perhaps) cause PEC curve
inaccuracies depending on which side of the pier you are shooting from.
It would be ideal to actually perform a Meridian Flip
after half the number of cycles – then have PemPro “Resume” the remaining raw
data collection cycles. But, that is not possible with the present program
method.
Either way – running right through PM, or “resuming” after a flip, would
produce data that may be closer to a true “average cycle” for the ideally used
CCD imaging span, across the PM.
Next time, I think I will go for the continuous PemPro
right across the PM, and “trust” that this provides better results.
Joe
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Re: APPM and Pinpoint
Wade,
https://www.faintfuzzy.net/2018/cone-1x1800-ha..fit.That is very odd as APPM plate solved almost instantly. I'll send you a screen shot. (BTW, there is a typo in the above link -- an extra period before ".fit") Best regard, -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message-----
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Re: PemPro Polar Alignment differs East to West
Hi Andrew,
Hi Ray. It was pretty much the same for both Alt and Az. I ran it a couple of times and some runs it showed up to a 7That may be a problem then for the refraction theory. By default PEMPro tries to account for refraction, but an East/West difference should not be evident for the Azimuth measurement. That's because the elevation of the star hardly changes during the Azimuth measurement (on East or West) and thus the refraction contribution is too small to make that much difference. If there was a difference in the East/West refraction contribution it would most likely be in the Altitude measurement because it is usually farther away from the meridian and thus the visual elevation of the star will usually change much faster. -Ray Gralak Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc Author of PEMPro: http://www.ccdware.com Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver Author of PulseGuide: http://www.pulseguide.com Author of Sigma: http://www.gralak.com/sigma -----Original Message-----
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Re: PemPro Polar Alignment differs East to West
Andrew Jones
Ray, why we are on the topic of PEMPro, I wanted to mention another issue I had last night. I kept getting an error last night when running step 3 of the Polar Alignment Wizard. Frustratingly it was always while taking the 3rd image in the series. The error message was "Error creating bitmap Min/Max 729/419. Parameter is not valid."
Any idea what might be causing this error? I got it both when my ATIK 16200 was connected via ASCOM directly to PEMPro and when connected via SGPro. I have never seen this error before when using SGP by itself. The only thing that seemed to allow me to get past it was to shut everything down, reboot, and then try and run it again. If you need me to send you the log files or anything else to help investigate let me know. Thanks for your never wavering support. Andrew J
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Re: PemPro Polar Alignment differs East to West
Andrew Jones
Joe. Thanks for the great info. What was strange in my situation is that I actually got my best results with the scope on the East side of the Pier looking West. It was not until I switched the scope to the West side of the Pier looking East that I started to notice a much larger discrepancy.
Would you recommend starting on one side of the pier vs the other or is it a matter of just having to get both sides about the same? I am targeting to stay below 3 arc mins on both sides if possible as I seem to remember reading somewhere that 3 arc mins is kind of the minimum for long exposures. Not sure how factual that information is thou as I think it may have been something I read on CN. Andrew J
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Re: PemPro Polar Alignment differs East to West
Andrew Jones
Thanks Rolando. I appreciate the detailed reply. It is comforting to know I am in good company with this issue. :D Next chance I get I will follow your advice and split the difference in the drift between the East and West side.
Andrew J
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Re: PemPro Polar Alignment differs East to West
Andrew Jones
Hi Ray. It was pretty much the same for both Alt and Az. I ran it a couple of times and some runs it showed up to a 7 arc mins difference in Az, but pretty much stayed in the 3-5 arc min range for Alt.
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Re: PemPro Polar Alignment differs East to West
Joe Zeglinski
Rolando,
I think I have found the solution to solving the
east-west PemPro curve difference. Simple really.
Atmospheric refraction is ALREADY being taken into
account by Ray’s PemPro algorithm, so it really should not be an issue here.
However, if there is even some slight variation, during the target run, greater
in the western part of the sky, one could very easily produce an “Averaged
East-West Pier side” curve by the following procedure:
Doing PemPro this way, the target has the SAME amount of
EVER decreasing & then increasing atmospheric refraction, for the same
number of cycles, split between the two sides of the pier.
What might make this easier, would be if PemPro could
make a note of the “actual” pre-meridian offset angle – since the user may have
caused some angle delay in preparation of the run, such as the required
Calibration wizardry, and run the other HALF of the cycles until the same
post-meridian angle is reached. At that point, PemPro automatically ends
itself, in preparation for the resulting raw data curve analysis
phase.
The option screen may need to be changed from choosing
the number of cycles, or duration – to time or angle ahead and after crossing
the meridian.
I think this would be ideal.
Joe Z.
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Re: PemPro Polar Alignment differs East to West
Roland Christen
Hi Joe,
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Thanks for your thoughts. One could try the zenith to see if the drift in Dec is the same on either side. By the way, I got to thinking about your daytime polar alignment routine and decided to modify it for our new mounts that have the 90 degree engraving marks on the axes. You must have the pier or tripod level for this to work. All you have to do is line up the RA and Dec engraved marks with the scope pointing to Park3 position (Home position) and tighten both sets of clutches. Then send the mount to either Park1 or Park4 and level the telescope tube assembly using the altitude adjuster. That's it, and now all you need to adjust is the azimuth angle and that can be done by sending the scope to the Sun (with proper filter or use the ring shadow method). Turn the azimuth until the Sun lines up with the scope. You may have to move the RA axis a small amount using the E-W buttons if your keypad time is off, then press Recal. Now you are ready to slew to other bright planets or stars. Rolando
-----Original Message-----
From: 'Joseph Zeglinski' J.Zeglinski@... [ap-gto] <ap-gto@...> To: ap-gto Sent: Sat, Mar 3, 2018 2:32 pm Subject: Re: [ap-gto] PemPro Polar Alignment differs East to West Hi Rolando,
I too have seen that PemPro curve results discrepancy on
runs east vs. west side of the mount.
I REALLY like your explanation, on the cause – even if the results might
sometimes be slight. They could be further exaggerating with poor seeing,
besides the atmospheric component adding to the discrepancy.
Yes - if you run PemPro with the “standard” setting of 5
minutes (deg ?) looking toward the east of PM, the OTA is “rising” and the
atmospheric refraction is “actually improving”, all during the hour long RAW
data sampling.
On the flip side, running with exactly the same PemPro
meridian target offset, the atmospheric refraction can ONLY
“degrade” steadily for the entire western sky target run.
So, you have the worst of both situations. You can
either trust the optimum raw data when PemPro runs from the west side of the
pier on eastern targets, or the twice as bad situation with “STEADILY
declining” target Altitude ... when running with the scope on the east
side (looking west).
I brought this up, on this Group probably more than a
couple of years ago, suggesting that PemPro could be run twice, and the two raw
data curves averaged – or their samples interleaved – to come to some averaged
curve result. Requires some further thinking, whether the results “should be
weighted” more toward eastern targets, Something for Ray to consider, based on
your premise.
Anyway, Rolando, thanks for this explanation of what has
been frustrating me about my own PemPro results ... for a VERY long time.
Unfortunately, in the short term, we just have to live with this minor
discrepancy.
Joe
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Re: PemPro Polar Alignment differs East to West
Joe Zeglinski
Hi Rolando,
I too have seen that PemPro curve results discrepancy on
runs east vs. west side of the mount.
I REALLY like your explanation, on the cause – even if the results might
sometimes be slight. They could be further exaggerating with poor seeing,
besides the atmospheric component adding to the discrepancy.
Yes - if you run PemPro with the “standard” setting of 5
minutes (deg ?) looking toward the east of PM, the OTA is “rising” and the
atmospheric refraction is “actually improving”, all during the hour long RAW
data sampling.
On the flip side, running with exactly the same PemPro
meridian target offset, the atmospheric refraction can ONLY
“degrade” steadily for the entire western sky target run.
So, you have the worst of both situations. You can
either trust the optimum raw data when PemPro runs from the west side of the
pier on eastern targets, or the twice as bad situation with “STEADILY
declining” target Altitude ... when running with the scope on the east
side (looking west).
I brought this up, on this Group probably more than a
couple of years ago, suggesting that PemPro could be run twice, and the two raw
data curves averaged – or their samples interleaved – to come to some averaged
curve result. Requires some further thinking, whether the results “should be
weighted” more toward eastern targets, Something for Ray to consider, based on
your premise.
Anyway, Rolando, thanks for this explanation of what has
been frustrating me about my own PemPro results ... for a VERY long time.
Unfortunately, in the short term, we just have to live with this minor
discrepancy.
Joe
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