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PHD2 is giving me trouble :(

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#1 Nikonist800

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Posted 24 April 2019 - 07:47 AM

Hello guys.

 

I need your expertise again. undecided.gif

 

 Have got my rig together now and adjusted, calibrated and learned everything I can about programming autofocus and creating sequences in SGp ect.

Everything seems to work as it should.

 

1. I do polar alinment through mount and then in sharpcap.
(Don't give up until I get "Exellent" and sets the Dec axis back to 0 degrees).

 

2. Mount is balanced.

 

3. The cables go up to a USB hub that sits centrally the mount for best balance.

 

4. I have adjusted all the backlash in both the RA axis and the DEC axis. (I can spin the gears easily with my fingers).

 

5. Everything is balanced and moves smoothly (with the focus tube protruding in the position where I have the best focus).

 

6. The guide camera has perfect focus.

 

7. I run ASCOM on everything

 

8. I do three-star alignment in EQMOD and it´s very precise. (Arcturus, Vega and Capella)

---

 

Now is the time to calibrate in PHD2 and start guiding.

I callibrate to the northwest with DEC axis between -20/+20 degrees as proposed by PHD2.

With moonlight in the south and excellent seeing.

I get no errors from calibration.

I do have a Dark Library.

 

Get RMS error between 2-3 after a few seconds and after a few minutes I'm well over 100.

 

I run Guide Assistance and entered the proposed values.

The same thing happens and PHD2 thinks that cables are snaged.
(They are not).

 

A few nights ago I managed to get down to 1 arc RMS error and it stayed there all night.
The evening after it returned to the same horrible values ​​that get worse the longer I go.

Both on RA and DEC.

 

Both nights had starry weather, no clouds and the moon was low on the horizon with quite a high magnitude. (yellowish faint color)

SNR on the stars in PHD2 is around 25.
---

I have been at it now for almost three weeks and I cannot for life in me get this to work.

 

Could it be because the guide camera does not sit 90 degrees parallel to the mount?

---

 

The gear:

 

Mount: SW HEQ5. (Orginal)

Telescope: SW 80ed 600mm FL

Guide camera: Orion Starshoot

Guide scope: Orion 50mm 162mm FL

Imaging camera: ZWO ASI 183 MM

Autofocus motor: Sesto Senso (to the right of the telescope)

 

I really hope one of you has gone through the same thing and can help me.
I humbly thank you. confused1.gif flowerred.gif



#2 happylimpet

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Posted 24 April 2019 - 08:22 AM

guide cam orientation shouldnt matter - ive used mine at a variety of angles.

 

possibly a stupid question - but is guiding enabled? this is a tick box in one of the menus.

 

maybe it is drifting off the guide star and not correcting, so the error is increasing?



#3 Tapio

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Posted 24 April 2019 - 08:36 AM

How is your guide scope attached?
Did you let PHD chose guide star ?

#4 Nikonist800

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Posted 24 April 2019 - 08:39 AM

guide cam orientation shouldnt matter - ive used mine at a variety of angles.

 

possibly a stupid question - but is guiding enabled? this is a tick box in one of the menus.

 

maybe it is drifting off the guide star and not correcting, so the error is increasing?

Hello and thank you for responding. :)
Yes I guess Guiding is enabled since I have never had to activate it before or disable it.
I'll check it out when I get off work. waytogo.gif



#5 Nikonist800

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Posted 24 April 2019 - 08:44 AM

How is your guide scope attached?
Did you let PHD chose guide star ?

I have tried to mount it both in the bracket on the side of the telescope and in the bracket which is centered on top of the telescope.

In these cases, I have put the "eye piece scope" (i don´t know what it´s called, sorry) in the bracket on the side for the sake of balance.

It makes no difference unfortunately. crazy.gif

 

Yes Phd2 always gets to choose my guidestar.


Edited by Nikonist800, 24 April 2019 - 08:46 AM.


#6 kathyastro

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Posted 24 April 2019 - 08:46 AM

Suspect the connections from the computer to the guide camera and to the mount.  If you are using an ST-4 cable, that is the first thing to suspect.  The RJ-11 connectors are not terribly high quality.  A direct connection from the computer to the mount is preferable for several reasons, and then you can junk the ST-4 cable.

 

Regardless of which cables you are using, check out all connections.  Make sure that all cables are anchored so that there is no weight on the connectors.  That is important!!  It is not enough to keep them from snagging.  You have to plan how to support the cables' weight so that there is not strain on the connector at all.  That usually requires a cable clip of some kind at the telescope end and another one at the other end.

 

Speaking of hubs, suspect your USB hub.  They go flakey after a while.  Cheap ones will go nuts after about a year.  Better ones last three to five years.  Have a spare that you can change out for diagnostic purposes or to replace one that has gone bad.  Assuming that it is a powered hub, have a spare wall wart for it as well.



#7 Nikonist800

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Posted 24 April 2019 - 09:00 AM

Suspect the connections from the computer to the guide camera and to the mount.  If you are using an ST-4 cable, that is the first thing to suspect.  The RJ-11 connectors are not terribly high quality.  A direct connection from the computer to the mount is preferable for several reasons, and then you can junk the ST-4 cable.

 

Regardless of which cables you are using, check out all connections.  Make sure that all cables are anchored so that there is no weight on the connectors.  That is important!!  It is not enough to keep them from snagging.  You have to plan how to support the cables' weight so that there is not strain on the connector at all.  That usually requires a cable clip of some kind at the telescope end and another one at the other end.

 

Speaking of hubs, suspect your USB hub.  They go flakey after a while.  Cheap ones will go nuts after about a year.  Better ones last three to five years.  Have a spare that you can change out for diagnostic purposes or to replace one that has gone bad.  Assuming that it is a powered hub, have a spare wall wart for it as well.

I do not use the ST-4 cable and have never done so. I run ASCOM directly from the computer.

The USB hub is 6 weeks old. It is a powered usb 3.0 hub.

 

Everything else works as it should through it though.

But that's a good advice. I will buy another usb hub to have as a spare.

I'll try to run the cable from the guide camera directly to the computer and ignore the USB hub.

 

Thanks smile.gif


Edited by Nikonist800, 24 April 2019 - 09:04 AM.


#8 bobzeq25

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Posted 24 April 2019 - 09:01 AM

That large an error is not anything small.  The cable/connection idea is a good possibility.

 

Note the description of this forum at the top of this page (the parenthetical part <smile>).  The moderators would like it if you post these inquiries in Beginning and Intermediate Imaging.  You''ll also get better answers there.


Edited by bobzeq25, 24 April 2019 - 09:02 AM.


#9 Nikonist800

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Posted 24 April 2019 - 09:10 AM

That large an error is not anything small.  The cable/connection idea is a good possibility.

 

Note the description of this forum at the top of this page (the parenthetical part <smile>).  The moderators would like it if you post these inquiries in Beginning and Intermediate Imaging.  You''ll also get better answers there.

Oh! I probably didn't read that carefully.
I promised earlier to be more careful.
I'm not good at this and my English is not the fastest.
I hope I will not be kicked from the forum. frown.gif

Good advice to check the connections. I will investigate tonight.

 

Thank you smile.gif



#10 Nikonist800

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Posted 24 April 2019 - 09:21 AM

Now that some of you have pointed out to check the connections, I realized that I have two USB extenders connected.
One 5 meter usb 3.0 connected to a 5 meter usb 2.0.

 

Could it be the error?

That there is too much traffic for the computer to be able to make enough quick corrections through these extenders and the usb hub to keep the RMS value low?

That would explain a lot.

 

confused1.gif



#11 Astrola72

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Posted 24 April 2019 - 10:07 AM

Since the mods haven't moved this to the right forum I'll reply here. I'm no expert and I can't explain technically, but I have experienced this problem when I calibrated PHD2 on one side of the mount, then imaged on the opposite side of the mount. You didn't say what you were imaging so I don't know if this is your problem or not.

 

Joe



#12 Ken Sturrock

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Posted 24 April 2019 - 10:09 AM

Moved from Beginners’ to B&II



#13 Nikonist800

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Posted 24 April 2019 - 11:08 AM

Moved from Beginners’ to B&II

Thanks smile.gif  And again, sorry.



#14 Nikonist800

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Posted 24 April 2019 - 11:14 AM

Since the mods haven't moved this to the right forum I'll reply here. I'm no expert and I can't explain technically, but I have experienced this problem when I calibrated PHD2 on one side of the mount, then imaged on the opposite side of the mount. You didn't say what you were imaging so I don't know if this is your problem or not.

 

Joe

Tried to calibrate on different sides of the meridian opposite to the side i´m imageing and have also tried to calibrate on the same side.

I have calibrated high and low.

I believe I've tried everything. Gonna check cables and connections tonight. smirk.gif


Edited by Nikonist800, 24 April 2019 - 11:14 AM.


#15 StephenW

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Posted 24 April 2019 - 11:53 AM

In your first post you state that calibration succeeds and it is only when you start guiding that things go wrong.

Do you do anything between completing calibration and starting guiding? Are you slewing to a new target?

Also, if you can upload your PHD2 guide log it might shed some light.

#16 Nikonist800

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Posted 24 April 2019 - 12:08 PM

In your first post you state that calibration succeeds and it is only when you start guiding that things go wrong.

Do you do anything between completing calibration and starting guiding? Are you slewing to a new target?

Also, if you can upload your PHD2 guide log it might shed some light.

Yes now that you mention it, I often calibrate near the horizon before I do plate solving to an object near my calibration.

But i know i have been calibrating spot on my objects also.

Is it better to place the telescope in the exact direction first before calibration you say?

 

From what i have understood the calibration should be done once and then you should be able to use the settings for a while. No?

My calibrations take 20-25 min so I don't like to do it every time. I should explore step sizes soon, i know.

I like to fix one problem at a time. This alone has been very stressful.

 

Tomorrow I will post the log files from PHD2. smile.gif


Edited by Nikonist800, 24 April 2019 - 12:09 PM.


#17 StephenW

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Posted 24 April 2019 - 12:14 PM

As you're connected via ascom you only need to calibrate once (intersection of meridian and equator is best) and you can re-use that calibration everywhere.

I am curious why you calibration takes 20+ minutes. Does this include GA? Or just basic calibration?

#18 Nikonist800

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Posted 24 April 2019 - 12:48 PM

As you're connected via ascom you only need to calibrate once (intersection of meridian and equator is best) and you can re-use that calibration everywhere.

I am curious why you calibration takes 20+ minutes. Does this include GA? Or just basic calibration?

No it does not include Guide Assistance.
But I suspect the cables and the usb hub now that people here on the forum have mentioned it.

 

You see, I run two usb-extensions one 3.0 and one 2.0 (5 meters each) connected together with female to female connector and then through my powered usb hub.

 

It may be that there is too much traffic through this single loop so PHD2 gets queue to get its corrections to mount?

Hence these huge deviations in RMS value?

 

It would explain why everything works as it should except the most sensitive operation in the entire rig. The guiding!

 

I will try to run the guide camera via its own USB cable directly to the computer and run the usb hub via the 3.0 cable so they both get a separate port in the laptop.

 

It just means that I have to have the computer outside at night and use the Teamviewer.

 

I´ll get back to ya´ll! flowerred.gif


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#19 Alex McConahay

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Posted 24 April 2019 - 08:30 PM

There could be lots of things going on......the ones I would check are:

 

Your calibration should be done not in the northwest, but at the celestial equator, pointing south (or north if you are south of the equator) IF YOU ARE USING DIRECT TO MOUNT CONNECT.

 

Your calibration should be done at the object you are going to image IF YOU ARE CONNECTED THROUGHT THE CAMERA (and ST-4 or "Guiding" port.

 

The difference is that PHD2 will read the mount if you are directly connected, and adjust your guiding parameters for declination. It cannot do that with the ON CAMERA connection. 

 

It never takes 25 minutes to CALIBRATE. It may take that long to polar align/drift align the mount. Are you confusing the two procedures?

 

You need to calibrate on every setup (or at least should) unless you have a permanently mounted setup. Changes in how you mount things can have some effect on guiding. So, you need to calibrate every night (and every target if not directly connected).

 

Are you imaging on the same side of the mount all night long? 

 

Is something slipping?

 

How about dew?

 

Alex



#20 pgandy

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Posted 24 April 2019 - 09:43 PM

I've thrown out a few bad (cheap) USB cables and stopped using extension cables altogether. I use one high quality USB 3.0 cable between the powered hub and laptop, 3 meter max and that stopped a lot of issues. That could also explain your extended calibration times. Calibration takes maybe 5 minutes?

 

Good luck!

 

Paul


Edited by pgandy, 24 April 2019 - 09:48 PM.


#21 Nikonist800

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Posted 25 April 2019 - 10:34 AM

There could be lots of things going on......the ones I would check are:

 

Your calibration should be done not in the northwest, but at the celestial equator, pointing south (or north if you are south of the equator) IF YOU ARE USING DIRECT TO MOUNT CONNECT.

 

Your calibration should be done at the object you are going to image IF YOU ARE CONNECTED THROUGHT THE CAMERA (and ST-4 or "Guiding" port.

 

The difference is that PHD2 will read the mount if you are directly connected, and adjust your guiding parameters for declination. It cannot do that with the ON CAMERA connection. 

 

It never takes 25 minutes to CALIBRATE. It may take that long to polar align/drift align the mount. Are you confusing the two procedures?

 

You need to calibrate on every setup (or at least should) unless you have a permanently mounted setup. Changes in how you mount things can have some effect on guiding. So, you need to calibrate every night (and every target if not directly connected).

 

Are you imaging on the same side of the mount all night long? 

 

Is something slipping?

 

How about dew?

 

Alex

Hey!
No I meant calibration in phd2 before guiding.
My polar alignment takes 5 min including sharpcap.
I will try to change some settings in the EQMOD.
(guidespeed and step size in PHD2).

 

I have tried to calibrate over the entire sky and have tried to guide in as many places.

Last night I got rms down to around 1.5 arcminut.
A couple of nights ago before I removed the extension cables I had one night with rms error around 1 arcminut.

Otherwise, I have gotten terrible values that get worse during the night.
So maybe I should look more closely at where I calibrate. Just as you say.

So I should aim for something to the south, between 20-30 degrees altitude and keep the DEC angle at 0 degrees? (if I put together all the advice I received plus what PHD2 thinks). Do you agree?

I have dew heaters so that's no problem.

Thanks for your reply.



#22 StephenW

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Posted 25 April 2019 - 10:48 AM

Your original problem was:

 

>Get RMS error between 2-3 after a few seconds and after a few minutes I'm well over 100.

 

Which seemed to indicate some form of run-away guiding.  Are you now able to keep RMS in your 1.5" range over a long duration of time?  This happened after removing your extension cables?

 

>So I should aim for something to the south, between 20-30 degrees altitude and keep the DEC angle at 0 degrees?

 

You should aim for somewhere just West of the intersection of the meridian and the equator - the exact altitude depends on where you are located.

 

At this point yo should probably upload a guide log showing yuor calibration, a GA run and at least 10 minutes of uninterrupted guiding and then people may be able to suggest ways to improve it.


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#23 Nikonist800

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Posted 25 April 2019 - 11:45 AM

The only thing I did differently yesterday was to remove the extenders, yes. 99% of the times before I have had as you describe run away guiding.

Except on that one occasion when I got an RMS value of around 1 arc-min. However, this was before I removed the extensions so I no longer suspect the cables.
I think I have a fully functional mount at least.

If the clouds stays away tonight i'm gonna try to calibrate as you describe. :)
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#24 Alex McConahay

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Posted 25 April 2019 - 12:23 PM

>>>>>>>> o I should aim for something to the south, between 20-30 degrees altitude and keep the DEC angle at 0 degrees?

 

On surface, that sentence does not really fit together. A dec of 0 degrees would not be too far south. (Unless you were very far north!!!)

 

DEC at 0 is a good idea. This is the celestial equator. But your altitude should be at 90 degrees, as close to the meridian as possible. 

 

And there is something seriously wrong about needing more than a minute or three to calibrate. All it is doing is taking a picture, moving, taking another picture, moving, and so forth for twenty or thirty pictures, each of a few seconds each.  Thirty exposures of four seconds would be maybe two and a half minutes max. 

 

Alex



#25 Nikonist800

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Posted 26 April 2019 - 09:21 AM

>>>>>>>> o I should aim for something to the south, between 20-30 degrees altitude and keep the DEC angle at 0 degrees?

 

On surface, that sentence does not really fit together. A dec of 0 degrees would not be too far south. (Unless you were very far north!!!)

 

DEC at 0 is a good idea. This is the celestial equator. But your altitude should be at 90 degrees, as close to the meridian as possible. 

 

And there is something seriously wrong about needing more than a minute or three to calibrate. All it is doing is taking a picture, moving, taking another picture, moving, and so forth for twenty or thirty pictures, each of a few seconds each.  Thirty exposures of four seconds would be maybe two and a half minutes max. 

 

Alex

Hello again.

 

Unfortunately, I didn't get a starry night yesterday so I could never get a calibration done.

 

I have been looking at Stellarium on why you are all mentioning the meridian and the equator in this context.

So If, as an example, I calibrate around Dec +20 degrees from the celestial equator to the south just on the side of the meridian, the stars look like moving only in the RA axis. Is this what one wants with the calibration?

 

Is it possible that the mount constantly works in the RA axis and only makes small adjustments in the Dec axis during the night?

 

I have always calibrated to the northwest and maybe 30-40 degrees in Dec.

(it´s in the direction I have clear view from where I have the telescope).

I trust that it will affect the calibration now when you say so, but I did not know that it would affect the performance of the guiding that much. (?)

Also, Can this be the reason the calibrations take such a long time?

 

I was looking for the logs in the PHD2 folders but I don´t seem to have them anywere. undecided.gif

 

Sorry if I am novice and ask stupid questions.
 

Thank you all so much for taking the time to help flowerred.gif


Edited by Nikonist800, 26 April 2019 - 09:24 AM.



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