guiding or mount issues

[Stan Howe]

I have been trying to resolve oval stars. They are primarily in the AZ direction, although there are sometimes some DEC movements. my guiding error never goes below 2" in the AZ. 

 I have read all the help documents and spent hours performing the testing. I have uploaded and can share the images via my drop box if it helps.  here are the guiding logs for an entire night of testing, https://openphdguiding.org/logs/dl/PHD2_logs_WB45.zip

I am uncertain, but i think it is issues withing the Fork mount on my CPC1100edgeHD. I disassembled and adjusted the backlash mechanism for both axis, I have BL comp turned off in CPWI and ON in PHD2 , however cant find any BL comp for AZ in PHD2 and testing shows stars moving back and forth in that axis a LOT. 

My mount is horribly out of balance after adding the .7 focal reducer and I have ordered more weights, but it is nearly impossible to ever balance a fork mount. 

 I have also found a thread on cloudy nights about the nylon bearing for the AZ axis getting flat spots when used on a wedge. new stainless ball bearings are on order.

any help is appreciated while i still have some hair left.

[Stan Howe]

I should mention, Guiding is a ASI174mm via the Celestron OAG, the scope is native F10 CPC1100edge HD with a .7 focal reducer, a starlight filter wheel, ASI294MC pro, mounted on a Wedge, attached to a permanent pier inside a skyshed Pod.

Also,  I just uploaded a image from the guide camera today to find true pixel scale, it was 2008 focal length, not the 1977 like the main camera, I have changed that in PHD2 but have not had a chance to test it.

Focus and Collimation are both good/great

[mj.w...@gmail.com]

Hi Stan

I suspect the Experts will also want a GuideLog that includes a Cal, as the last one was carried out a week before, on the 17th.

Because although the mount Guide Rate is set to RA Guide Speed = 12.8 a-s/s, Dec Guide Speed = 12.8 a-s/s,

About 0.85 of Sidereal.

The actual Guide Rate measured by PHD2 was Norm rates RA = 28.3"/s @ dec 0, Dec = 25.3"/s

Or about double the setting in the mount.

Which may explain the constant over-correction of RA guiding.

But that's for the Experts :-<

Michael

Wiltshire UK

[Bruce Waddington]

There really isn’t enough information in this log to get a good idea about what’s wrong – certainly you are trying to use a poor calibration which is a show-stopper for analysis.  There isn’t much point in spending the time to isolate these problems when you already know you have mechanical problems.  If the scope is badly out of balance on the fork, you are likely to get poor results, particularly in RA (not “AZ”).  Guiding isn’t affected by any backlash in RA so we don’t worry about that.  But if the RA drive gears aren’t fully engaged as the mount tracks at the sidereal rate, you will have problems.  So if the imbalance is causing the scope to “fall” to the west at any point, it’s a problem - you shouldn't be able to sense any obvious "slop" in RA.  I don’t really agree with your assessment that it’s nearly impossible to balance a fork mount, only that it can be a bit tedious.  I imaged with a fork-mounted LX200GPS for years and it was well-balanced in all pointing positions.  You typically need to have the “3-dimensional” balancing kits for this whereby some of the small weights slide up and down on a rod that is perpendicular to the OTA.  It can be done and it needs to be done to a reasonable level of accuracy in order for guiding to work well.

I think you should concentrate on fixing the mechanical problems you know you have, then make a systematic effort to measure how well the mount behaves.  All of this diagnosis needs to be done without trying to use an automation app, it needs to be done manually.  You can use this procedure for getting a measurement baseline:

 https://www.dropbox.com/s/os1thorvswmzaul/How%20to%20create%20a%20baseline%20for%20guiding%20results%20using%20OpenPHD2.pdf?dl=0  

 I also suspect your guide camera isn’t well-focused so you should probably spend some time on that up-front.  You need to use some sort of measurement assistance for that – PHD2 Star Profile, Bahtinov mask, another app like SharpCap, etc – you can’t do it by just looking at the display.  You should also bin your guide camera 2x2 which should allow you to use shorter exposure times and improve the SNR of your stars.  In your case, you should rebuild your profile from scratch, which is the first step in the above procedure, including construction of a dark library.

Good luck,

Bruce

[Stan Howe]

thanks Michael, I'll look into the speed settings again but am confused as I had set them in CPWI to 65 and 55% based upon testing with the star pattern in PHD2. every time I check the setting in PHD2 it has reset to .85, i'll change it and do the advanced calc, but next time i look at it, it is back to .85.

[Stan Howe]

Thanks Bruce, very good advice. 

most every calibration I have tried except for a few have errors. I thought the one I was using was one of the error free calibrations, and I wasn't aware they would want to see that. I will certainly ensure i do one during the next testing session, after the mechanical repairs.  I did create a new profile using the wizard, which erased my dark library. I did not have time to create a new one before the clear sky evening, which is so rare lately so, i tested without it. I also did not realize NINA would affect any testing, I figured that's how I mage, I should test in the same manner, I'll give the manual method a try. I used to have the camera binned 2x2, and didn't realize I lost that when creating the new profile. I did feel i had a pretty good focus on the guide camera, BUT I did not use my bahtinov mask and have since read that internet rumor that allowing it to be a little out of focus was good for PHD2 is all hogwash. I'll add refocusing the guide camera to my to-do list.

I do have a Losmandy 3D sliding balance system, but with only a 2.5 lb weight it is slid as far forward as possible without hitting the mount when I park the scope. I have ordered a 5lb weight to try on it. but I had to cut the adjustment bolt shorter to clear the mount, so i wont have much perpendicular adjustment with a larger weight. I was reasonably close to balance before adding the .7 focal reducer which s real heavy and thru the balance out the window. I added washers a lead weights i had on hand but they clearly are not enough.

Thaks again for the input, other than the mechanical repairs, I was at a loss for what my next steps would be. Now I have many steps on my observatory to-do list.

[Bruce Waddington]

Hi Stan.  The new-profile-wizard includes an option to bin the camera, so you must have blown through that step.  You should probably discard that profile and just build a new one, being careful to look at all the UI choices and choose to bin the camera 2x2.  In response to your earlier post, PHD2 NEVER changes the guide speed in the mount, there is no code to even do that.  If it's changing on you mysteriously, that's coming from somewhere else or you aren't getting through the driver configuration interface correctly.  There's no benefit to using different guide speeds on the two axes and the value of 0.85x sidereal should be fine.  Just be sure to specify that guide speed when you run the new-profile-wizard so the wizard can compute a reasonable calibration step-size.  The reason for doing the manual baseline without NINA isn't because NINA does anything nefarious - it doesn't.  But you want to have full control over everything that happens during the testing without another app banging away in the background trying to do what it wants.  The goal in doing the baseline measurement isn't to magically fix something and get good guiding - that isn't going to happen.  Instead, the goal is to understand what your mount is capable of doing on its own and how best to employ the software to help mitigate its shortcomings.  Finally, the new-profile-wizard didn't throw away your dark library unless you deleted the old profile, but you need to build a new one anyway in order to use binning. 

Good luck,

Bruce

[Stan Howe]

I have been sitting here trying to remember how i focused the guide camera last time, I believe I was watching the HFR numbers in PHD2 and trying to achieve the lowest, but it was difficult. 

clarification: PHD2 did not change the guide speed of the mount, just the field for guide speed in the "Calibration Step" calculator would reset to .85.

I think you are right, I blew by the binning in the wizard, and thus my old dark library (which was done at 2x2) did not match and therefore PHD2 told me there was no dark library and it would need to be created from scratch. My previous dark library was about 6 months ago. I wonder if PHD2 will find it when i run the wizard again?

[Stan Howe]

FYI, I created a new profile with 2x2 binning and a new Dark library. I hadn't thought of it before, but PHD2 could not use the previous dark library because of the new focal length caused by the .7 focal reducer. I measured it the other night by uploading a guide camera image to astrometry.net. My native focal length is 2800, the ballpark .7 reducer would be 1960, but the measure pixel scale of .602 arcsec/pixel calculates to 2008. When I enter that in PHD2,  it display's a pixel scale of 1.2 at 2x2 binning. I toggled it to 1x1 momentarily and it display's .60 so it made sense to me for it to be twice that at 2x2. 

 Amazon says my new ball bearings will be here tomorrow, still no shipping confirmation on the new balancing weight. Only clear night in the forecast that fits my work schedule is Thursday and It is likely that I won't have the mechanical stuff done by then, so it will probably be the following weekend before I can test again.

Thanks again for the guidance, with your help I am optimistic that there are round stars in my future.

[Bruce Waddington]

Don't try to over-think this stuff. :-)  Dark libraries aren't dependent on the focal length or the image scale.  PHD2 is just checking the dimensions of the images that will be returned from the camera - so an un-binned dark frame can't be used when the camera is binned.   Just to nail down this business with the mount guide speed: 1) if you need to change the mount guide speed - and you don't at this point - you must do that through the ASCOM driver interface or the hand-controller and 2) the PHD2 calculator tool will always populate the guide speed box with the actual mount guide speed.  You can change it in the calculator UI if you want to experiment with settings but any changes you make in the mount guide speed field will be discarded when you close the calculator.  if your dark library is 6 months old, you should probably rebuild it in any case - it doesn't take that long and camera sensors change over time.  One thing you can do to make the focusing easier is use longer exposure times than you normally would.  This will help with all the seeing effects and you can move to progressively fainter stars.  Just don't try to focus on a saturated star or one with a flat top in the Profile window.

Bruce

[Stan Howe]

SO,.. my mechanical issues have been solved. I replaced the RA ball bearings, found and tightened a loose set screw in the DEC clutch, some basic clean and re-grease. I also was able to get it balanced perfectly in 3D with some temporary weights ty-wrapped in place. A permanent solution is on order. I did get a couple hours of clear skies last night and verified guide camera focus with a bahtinov mask. (I tweaked focus slightly, but it was real close, before). I ran a successful error free calibration and was working on fine tuning the RA polar alignment when the clouds shut me down for the night. I did manage to sneak in a couple long exposures and the stars were still oval.Hopefully I'll get some clear skies Sat and/or Sun night to finish polar align and perform the baseline test. 

I'm confused about your guide speed comments. I installed ASCOM platform and drivers, but have never touched it after that. My mount is controlled by CPWI (and associated ASCOM drivers) I change guide speed in CPWI which has all the same settings that would be found in the hand control of the mount. I have set them both to .85 in CPWI and the Calibration still reports them at RA Guide Speed = 12.8 a-s/s, Dec Guide Speed = 12.8 a-s/s,. The measured rate per PHD2 is now Norm rates RA = 25.4"/s @ dec 0, Dec = 21.9"/s. Would not the rate change depending upon where my scope is pointed? For example it would be a snails pace if pointed at Polaris, and a race car if pointed at the equator?

[Bruce Waddington]

The pointing position of the scope at the time of calibration is taken into account - that's what "normalized" means in this context. The normalized rates should never be nearly 2x the actual speed used in the mount firmware. At Dec = 0, they should be close to the mount guide speed the mount is using, around 12.8 arc-sec/sec in your case.  Something is wrong with either the CPWI software or the mount or you're not using the focal length you have specified (1977mm).  If you do the baseline run we can get better information.  If you do that and still see this big disparity, you should run a Star-Cross test at the same sky location where you did the calibration (near Dec=0) (explained in the PHD2 manual in the trouble-shooting section).  The resultant image will provide a clear and unambiguous verification of what PHD2 is seeing. 

Bruce

[Stan Howe]

After a few clouds early, (in the one spot that i needed to begin PA) I finally got a clear night, I was up to 5am trying to solve this issue and create a baseline. Initially I was getting calibration errors, both angular error and rate error. 

I have a permanent setup on a pier and my past PA was via NINA 3 point alignment, prior to that I used PHD2 drift alignment but was always interrupted by clouds or the moon before I was totally satisfied with the results.  Last night I spent the majority of the night trying to get PA error below 1' or even 0.5' if possible. I was very slow and methodical letting the drift run for the full 400 frames unless it was way off. My last attempt left it at Azimuth= -0..05' (2 pixels) and Altitude = -0.43(22 pixels). I also reperformed a sky alignment in CPWI and my subsequent goto on the Dumbell nebula was spot on.

Yet, the graphs and errors still indicate that I have an RA issue. (this may be the guiding speed issue mentioned in previous posts above) I thought I had drift alignment tool understood until I saw one thing in the tutorial in the manual that confused me. When checking and adjusting the Azimuth, it says to watch the DEC line. that blows my mind , but I was instead watching the error numbers and using the positive or negative sign to determine the correct direction to adjust.

LOG FILE

https://openphdguiding.org/logs/dl/PHD2_logs_epJN.zip

much of this log includes a night full of drift alignment. However at 02:26 (log 30) I got a successful calibration and at 02:27 (log 31) ran the guiding assistant. At 2:32 (log 32) I started the baseline guiding. It lost the star briefly, I'm not sure why as it was clear skies, I presume I may have bumped the main camera when I was reaching for my mouse in the dark as it was very close to my work shelf in my pod. At 03:05 (log 33) I realized that I still had the camera at 1 second from the drift alignment, so I began another guiding test at 1.5 seconds, and after 20-25 minutes began a long run of the guiding assistant to see the mount behavior. (the RA is still terrible)

I think log 34 was me slewing to the Dumbell Nebula after starting NINA to take a test image before the sun came up or maybe a plate solve and slew

 log 35 was the first 180 second image on the Dumbell where I had round stars but could see they were out of focus as the scope had cooled significantly since my last focus. I followed this with an autofocus run in NINA (affects the main camera and the guide camera as I run a OAG

 

Log 36 was a final 180 sec where i had mostly round stars, with small tails in the AZ direction (I think they were pointing East). this is an improvement over where I started, but obviously I still have something wrong in RA direction, I'm unsure what. Screen shot of the image attached) 

[Stan Howe]

P.S. Happy 4th of July

[Bruce Waddington]

Hi Stan, same to you.  I really don't know why you spent the whole night doing polar alignment, that has absolutely nothing to do with your guiding problems.  Your problem is that you are getting consistently bogus calibration results.  In the three calibrations you did, the derived RA guide speeds were 40 arc-sec/sec, 24.5 arc-sec/sec, and 24.5 arc-sec/sec again.  Those are just wrong.  I suspect your camera isn't binning the images 2x2 as you've specified which means the image scale is wrong by 2x.  In that case, your calibration results would be much better and your guiding results would be much better than you think.  Please connect to this profile again, capture a guide camera image (File/Save...) and then open that in an image viewer.  What is the size of the image?  I suspect it's going to be 968x608 pixels, which is the un-binned frame size.  If that is the case, you should create a new profile specifying un-binned ops and try to get a good calibration.  This doesn't explain everything but we could at least be looking at something that makes more sense.

Regards,

Bruce

[Stan Howe]

Calibration errors, indicated a potential issue could be my PA, so I figured I would check it, and when I found it several arc minutes out, I decided to make it as good as I could to eliminate it as a possibility. PHD2 still told me it was way out at times.

 I don't have a 2x2 image from the guide camera, i'll have to put that on my todo list for the next clear night. I do have a saved 1x1 image from the guide camera, it is listed as 1936 x 1216 in the fits header, this matches the ZWO spec. When uploaded to astrometry.net it reported 19.4 x 12.2 arcmin, with a .602 arsec pixel scale. When I set it to 2x2 in the new profile wizard, PHD2 reported 1.2 arcsec pixel scale, which seamed ta agree with Astrometry.net This image, however was taken through NINA and not PHD2 . I did not know I could save a pic directly from PHD2, Thanks for the tip.

[Bruce Waddington]

Ok then, my mistake, you probably are getting binned images.  That still leaves us with the basic problem - until you get the calibrated RA and Dec guide rates down where they belong - about 1/2 of where they are now - you aren't going to get anywhere.  That leaves us with two other places to look - either the CPWI driver or the mount firmware itself.  Here's another approach you can try:

1.  Make sure the scope is well-balanced in RA and the clutches are tight.

2.  Create a new PHD2 profile with camera = your current ZWO 174MM, mount = 'On Camera', and Aux-Mount = your current CPWI driver.  You can keep the binning at 2x.  In the new-profile-wizard, specify a guide speed of 0.75x sidereal for now.

3.  Connect a guide cable between the ZWO camera and the guide port on the mount

4.  Do a calibration as you have been doing so far.  Then use the Calibration/Review dialog to see what guide rates are measured by PHD2.  We're looking for values that are below 15 arc-sec/sec, how far below isn't important right now.

5. Tell PHD2 to save one of the guide camera images using the 2x2 binning - I would like to see that as well.

This takes CPWI out of the picture in terms of actual guiding so it should tell us something either way.

Bruce

[Stan Howe]

OK, so I use the ST4 port?  I have never used it, but believe I have a cable that will work. I've seen instruction for people who do use ST4 to also connect an ASCOM connections the "Aux Mount" to get mount feedback. would need to bother with that for this or just the ST4?

I have received my new parts to add a sliceable weight to the top of the scope vs the temporary ty-wrapped weight I have now. I plan to get that installed today and will set up the new cable and profile as well. However, the current forecast has no clear skies until Saturday, and have to get up early Sunday for work, so I probably won't be able to test this until next Wednesday at the earliest.

[Stan Howe]

I found the cable.  The Cloud gods may give me an opening at 1am according to the last forecast (raining earlier). We'll see, however I don't think this will work as you intended. I tried to connect using Celestron Driver (ASCOM) with 2 different cables that each work via CPWI, but PHD2 could not find the mount without CPWI acting as the sever. I did notice when i opened and selected CPWI that the default guide speed in PHD2 was .5 which was changed to CPWI setting of .85, I can reset CPWI to .5 easily for both axis. When I ran several star cross test  back in the beginning of June I had tested many combinations of guide speeds and landed on RA of .65 and DEC of .55, howe I never tested the default of .5 and .5, I had put them both back to .85 based open feedback from this group. I'll experiment some more tonight, depending on how much time i have.

[bw_m...@earthlink.net]

I don’t really understand what you’re doing.  You have to be sure the guide cable from the camera to the mount is really a guide cable – it should have come with the guide camera.  It won’t be the same as what you use for an ASCOM mount connection.  The Celestron ASCOM software should have nothing to do with ST-4 (on-camera) guiding.  Doesn’t your mount have a separate ST-4 guide port? When you connect with the “on camera” connection in PHD2, that should be the end of it.  If you follow the instructions I gave below – steps 1 through 5 – it should work.  If you can’t figure out how to use the Aux-port connection, just skip that step.  All you’re trying to do is get a decent calibration.

 

Bruce

Log 36 was a final 180 sec where i had mostly round stars, with small tails in the AZ direction (I think they were pointing East). this is an improvement over where I started, but obviously I still have something wrong in RA direction, I'm unsure what. Screen shot of the image attached) 

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[Stan Howe]

Yes, the mount has a guide port and the cable connected from there to the camera. the problem is PHD2 is located on my laptop and my laptop needs to connect to the mount. I have 3 choices for mount connection to the laptop: 1) a USB to cable that connects into the hand controller via a serial port(my normal method) 2) a home-brew serial adapter from an Aux port to Ethernet, 3) a Wifi dongle that plugs into an aux port(have had issues with this in the past, don't know where the dongle is, didn't try this method) 

I tried Celestron drivers in PHD2 but it could not find the mount with either cable arrangement. When I select CPWI in PHD2 int connect immediately via CPWI.

I did get that guide camera pic tonight. I uploaded it to astrometry.net and the image scale is 1.21 AS/pixel which is very close to the 1.2 as/pixel I entered in PHD2

[Stan Howe]

I played with the guide speed settings in CPWI first at .5 then .3 , then .2 eventually set it at 0 and got down to 14arcsec/sec with a successful calibration. I attempted to reperform the baseline, but before i could get started, the clouds shut me down. see the final calibration in this log.  https://openphdguiding.org/logs/dl/PHD2_logs_orCG.zip

I also did the star test when i had GS set to .5, other than backlash and a little drift on the north run, it seems pretty balanced. 

[Stan Howe]

oops reviewing the calibration data it was 14 arcsec/pixel, and 17.8 arcsec/sec , oddly enough it says guide rate is still .85 , my RMS error is now below 2 but I still have oval stars.

[Bruce Waddington]

Hi Stan.  As far as I can see, you didn't do the experiment I suggested - there's nothing in the logs you sent to show you created a new profile or used ST-4 guiding.  Here were the instructions:

Since nothing changed, we haven't learned anything and i don't know what else I can tell you.  The difference between using ST-4 and ASCOM guiding is discussed in the Basic Use section of the manual which I assume you have studied.  You might find it easier to ask for help elsewhere, perhaps on one of the Celestron forums or Cloudy Nights.  There are hundreds or even thousands of PHD2 users with Celestron mounts,  probably including the model you have.  I haven't seen a case before where the measured guide rates are so much higher than they should be which suggests to me there is something wrong with the mount firmware or something is mis-configured in CPWI.

Sorry,

Bruce

[Stan Howe]

because i cant figure out how to connect PHD2 to the mount WITHOUT also having CPWI on. I tried, but when using the wizard to create the new profile, PHD2 cannot find the mount, so i canceled it.

I guess im stuck with football shaped stars until i rebuild my whole observatory and install a $4000 mount, de fork this piece of crap.

[bw_m...@earthlink.net]

That’s why I gave you the instructions.  If you use ‘on camera’ for the mount connection, that’s it.  PHD2 doesn’t try to “find” the mount and it won’t use the CPWI mount interface.   The guide commands go from PHD2 to the guide camera and then on to the mount via the ST-4 cable.  But you should proceed as you think best.

 

Good luck,

Bruce

 

From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> On Behalf Of Stan Howe
Sent: Saturday, July 9, 2022 1:58 PM
To: Open PHD Guiding <open-phd...@googlegroups.com>
Subject: Re: [open-phd-guiding] Re: guiding or mount issues

 

because i cant figure out how to connect PHD2 to the mount WITHOUT also having CPWI on. I tried, but when using the wizard to create the new profile, PHD2 cannot find the mount, so i canceled it.

I guess im stuck with football shaped stars until i rebuild my whole observatory and install a $4000 mount, de fork this piece of crap.

On Saturday, July 9, 2022 at 11:41:58 AM UTC-4 bw_m...@earthlink.net wrote:

Hi Stan.  As far as I can see, you didn't do the experiment I suggested - there's nothing in the logs you sent to show you created a new profile or used ST-4 guiding.  Here were the instructions:

 

Since nothing changed, we haven't learned anything and i don't know what else I can tell you.  The difference between using ST-4 and ASCOM guiding is discussed in the Basic Use section of the manual which I assume you have studied.  You might find it easier to ask for help elsewhere, perhaps on one of the Celestron forums or Cloudy Nights.  There are hundreds or even thousands of PHD2 users with Celestron mounts,  probably including the model you have.  I haven't seen a case before where the measured guide rates are so much higher than they should be which suggests to me there is something wrong with the mount firmware or something is mis-configured in CPWI.

 

Sorry,

Bruce

On Saturday, July 9, 2022 at 12:58:36 AM UTC-7 Stan Howe wrote:

oops reviewing the calibration data it was 14 arcsec/pixel, and 17.8 arcsec/sec , oddly enough it says guide rate is still .85 , my RMS error is now below 2 but I still have oval stars.

On Saturday, July 9, 2022 at 3:23:42 AM UTC-4 Stan Howe wrote:

I played with the guide speed settings in CPWI first at .5 then .3 , then .2 eventually set it at 0 and got down to 14arcsec/sec with a successful calibration. I attempted to reperform the baseline, but before i could get started, the clouds shut me down. see the final calibration in this log.  https://openphdguiding.org/logs/dl/PHD2_logs_orCG.zip

 

I also did the star test when i had GS set to .5, other than backlash and a little drift on the north run, it seems pretty balanced. 

 

 

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[Stan Howe]

ill give it another shot, but my research online only found a cloudy nights thread that supports my understanding.  https://www.cloudynights.com/topic/823244-autoguiding-without-nexstar/?hl=%2Bnexstar+%2Bconnection#entry11919975

[Stan Howe]

Success! at least in the first 3 steps. I was able to connect PHD2 to the mount via the ST4 after following your instructions to the letter. (I had missed the "On Camera" part the first time.) Forecast is for a clear night tonight so hopefully I can complete the rest of the test.

I did have one odd notice appear while setting up the wizard. I set the guide speed to .75 as instructed, but after selecting CPWI as the Aux mount, this message appeared at the bottom of the screen. "Guide speed setting adjusted from 0.8 to 0.8x"

[Stan Howe]

well, I'm stuck again. I'm connected to the mount through ST4 as described. I used the slew button in the drift align tool to slew to 0-0, worked great, but then I tried to use the manual align buttons to move the mount and could not see any star movement. I can move the star using CPWI slew controls. I tried a calibration anyway, the star never moved and PHD2 eventually timed out reported too little star movement. I even tried setting the manual guide tool to 5000ms pulses and could see no star movement. I checked that it is connected via "on camera" and re-tried all the above again with the same results. I'm at a loss as to what to do next with this POS.

[bw_m...@earthlink.net]

Are you entirely sure you have a real ST-4 cable, presumably the one that came with the guide camera?  Is it plugged in to the guide port on the mount, the one identified as ‘D’ in this diagram: 

 

 

 

There should be nothing plugged into the ports marked as ‘B’.  What do you mean you slewed to 0-0 – where is that?  You should be pointing somewhere near Dec = 0, not near either the east or west horizon.  It’s always possible the ST-4 cable is damaged or you’re using some other kind of cable that happens to have RJ-11 connectors on each end.  I don’t know how else to help you – I can’t see what you’re doing.  ST-4 guiding is usually the simplest to set up.  Again, you might be better off asking on one of the Celestron forums.

 

Bruce

From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> On Behalf Of Stan Howe
Sent: Thursday, July 14, 2022 7:28 PM
To: Open PHD Guiding <open-phd...@googlegroups.com>
Subject: Re: [open-phd-guiding] Re: guiding or mount issues

 

well, I'm stuck again. I'm connected to the mount through ST4 as described. I used the slew button in the drift align tool to slew to 0-0, worked great, but then I tried to use the manual align buttons to move the mount and could not see any star movement. I can move the star using CPWI slew controls. I tried a calibration anyway, the star never moved and PHD2 eventually timed out reported too little star movement. I even tried setting the manual guide tool to 5000ms pulses and could see no star movement. I checked that it is connected via "on camera" and re-tried all the above again with the same results. I'm at a loss as to what to do next with this POS.

On Thursday, July 14, 2022 at 6:51:47 PM UTC-4 Stan Howe wrote:

Success! at least in the first 3 steps. I was able to connect PHD2 to the mount via the ST4 after following your instructions to the letter. (I had missed the "On Camera" part the first time.) Forecast is for a clear night tonight so hopefully I can complete the rest of the test.

 

I did have one odd notice appear while setting up the wizard. I set the guide speed to .75 as instructed, but after selecting CPWI as the Aux mount, this message appeared at the bottom of the screen. "Guide speed setting adjusted from 0.8 to 0.8x"

 

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[Stan Howe]

Yes, its plugged into guide port, my EFM is plugged into one of the aux ports. I did ask on a Celestron forum last week, still no reply. the cable is home made, but only after finding the pinout required for ST4 on Celestron mounts. the location in the drift align tool for Azimuth Adjustment = 0 Meridian offset, 0 Declination as described in the document on obtaining baseline data.

[bw_m...@earthlink.net]

Sorry, what is an ‘EFM’?  Historically, we’ve seen bizarre problems when things are plugged into the aux ports.  If possible, try temporarily disconnecting whatever it is.

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[Stan Howe]

electronic Focus Motor. I'll try disconnecting it

[Stan Howe]

same results. it blows my mind that PHD2 can slew the scope, but cant send it guide pulses.

[bw_m...@earthlink.net]

This is not a PHD2 problem.  Either the mount can’t be guided at all or you’ve got something screwed up with how things are connected or you made a bad ST-4 cable.  If you built the ST-4 cable yourself, measure the voltages on the pins when you tell PHD2 to send guide pulses.  There is no round-trip validation for ST-4 guiding – PHD2 tells the guide camera to send a guide pulse, the guide camera hopefully does that, and the mount hopefully responds to it.  That’s how it works.  The hardware and software paths are COMPLETELY different for slewing and ST-4 guiding.  I’m sorry, I don’t think I can help you any further on this.

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[Stan Howe]

Thanks for the attempt at solving my issues. I may reach out to Celestron and see if they have any ideas, although my experience with their tech support has not been good. I have started preliminary research and measurements to design a new roll off shed so that I will have the space for a GEM mount. Once that is complete and the budget allows, I'll de-fork this POS. not sure what to do with imaging in the meantime, as that is a real long range fix. I guess I live with oval stars.

[Stan Howe]

Update:

After finding a thread on cloudy nights, where a user was having similar issues using CPWI and his solution was to connect via Celestron ASCOM driver, I tried the same and it worked. I didn't get much time to test or do a full baseline due to the moon and thin clouds joining the party, but the calibration numbers look very promising. the guide speeds were actually LOWER than expected, more tweaking of settings may be able to resolve that. However it requires me to align with the hand controller each night instead of using a saved multipoint alignment in CPWI and a few other bells and whistles are missing, but it it is functional. I think I have enough info to approach Celestron for an explanation.

[Stan Howe]

ironically they say they fixed this issue in the latest version, which I am running!