I can't seem to guide anymore, PHD2 not giving me round stars!

[Quetzalcoatl72]

I just want to guise 4 minutes thats all, i've done it before but now it's acting up, seems like ra and dec are way off than what they should be, i've reset everything and ran the guide assistant, but i'm still getting slight trails. Good balance and polar alignment etc i have im sure. I'm not sure much about the balance i was told to have it slightly east heavy, i'm currently pointing at triangulum. Can anyone figure this out thanks

[Quetzalcoatl72]

heres the graph

[teoria_del_big_bang]

I am certainly no expert in PHD2 and issues with PHD2 but to me looks pretty good until it dithers, also why do you have so much backlash in Dec.

Steve

[Quetzalcoatl72]

1 hour ago, teoria_del_big_bang said:

also why do you have so much backlash in Dec.

Steve

I don't know, that's what i'm trying to figure out

[teoria_del_big_bang]

Sorry for stating the obvious but is clutch tight ?

Is a belt slipping ?

But why it seems to go mad after a dither I do not know, what if you turn dither off in PHD2 ?

Steve

[Quetzalcoatl72]

everythings fine in those dummy departments, do i really need dithering?, people say dither or die so i dunno

[teoria_del_big_bang]

Dithering is certainly worth it, but all depends on camera really how much it is needed.
But my suggestion to turn off dithering was really just a test to see if the guiding remained reasonable for much longer.

I do not think dithering is the cause of your issue but does seem to initiate the problem.
Surely the problem is the amount of backlash in DEC.

In daylight with power on but not tracking can you physically feel any movement in DEC if you twist it by hand ?

Can you take the cover off to look at the belts, does anything look odd, could they be slipping, start it off tracking with cover off see if you can see anything odd, can you move anything with your fingers that can cause this backlash ?

I have a belt modded HEQ5 I can take covers off and watch it track I am assuming the NEQ6 is similar ???

Steve

[Quetzalcoatl72]

10 hours ago, teoria_del_big_bang said:

Surely the problem is the amount of backlash in DEC.

In daylight with power on but not tracking can you physically feel any movement in DEC if you twist it by hand ?

Can you take the cover off to look at the belts, does anything look odd, could they be slipping, start it off tracking with cover off see if you can see anything odd, can you move anything with your fingers that can cause this backlash ?

I have a belt modded HEQ5 I can take covers off and watch it track I am assuming the NEQ6 is similar ???

Steve

no the neq6 is a pain, you can't see anything unless you fully dismantle, but then there's no point because nothings connected. The mount also never had a belt, I modded it to have one installed and it worked great. Both dec and ra are stiff when locked up. I recently changed the bearings because they were damaged, everything physically feels solid and smooth... however i notice slight knocking when it it making the corrections in guiding.

[teoria_del_big_bang]

If it is similar to the HEQ5 there should be two taper bearings inside one on the dec and one on the ra, if you replaced those you have to be super careful how much pre-load you put on them when tightening the nut that brings the two halves together, it really is just a tad (I mean a tad) more than hand tight otherwise the axis may still be smooth but the extra pressure will mean the axis stalls very easily, although more noticeable if you slew it at full speed I suppose a quick sharp movement when dithering could cause it to stall and may then interfere with the tracking.

Is there any chance you have replaced these and over tightened them ?

In the HEQ5 they are as below.

Steve

 

[michael8554]

As in your previous NEQ problems, diagnosing without a GuideLog is just guesswork.

But from your screenshot, before the DIther, Dec did not need any guiding, so PA must have been pretty good.

As soon as Dec guiding was required following the Dither, PHD2 was failing to pull Dec back.

Because of Stiction in Dec at a guess.

Michael

[Quetzalcoatl72]

On 25/01/2022 at 19:08, teoria_del_big_bang said:

If it is similar to the HEQ5 there should be two taper bearings inside one on the dec and one on the ra, if you replaced those you have to be super careful how much pre-load you put on them when tightening the nut that brings the two halves together, it really is just a tad (I mean a tad) more than hand tight otherwise the axis may still be smooth but the extra pressure will mean the axis stalls very easily, although more noticeable if you slew it at full speed I suppose a quick sharp movement when dithering could cause it to stall and may then interfere with the tracking.

Is there any chance you have replaced these and over tightened them ?

In the HEQ5 they are as below.

Steve

 

I just cleaned and re-greased them. I replaced the smallest bearings that are on the worm shaft, which i recommend btw the old ones aren't great, it has thin metal rings that can easily get dinged up, the new ones i put in are rubber and they turn a lot smoother

Edited January 27, 2022 by Quetzalcoatl72

[Quetzalcoatl72]

On 25/01/2022 at 20:09, michael8554 said:

As in your previous NEQ problems, diagnosing without a GuideLog is just guesswork.

But from your screenshot, before the DIther, Dec did not need any guiding, so PA must have been pretty good.

As soon as Dec guiding was required following the Dither, PHD2 was failing to pull Dec back.

Because of Stiction in Dec at a guess.

Michael

I managed to get this on the night i started this thread regardless of some eggy looking stars, i think i ended up setting dec to guide north only

[michael8554]

Shows that Dec Guiding in one direction works, if correctly implemented.

Michael