Frustrating night of guiding-failure

[Demonperformer]

In truth, I should have known that last night was going to be bad right from the start. I had decided that, to save having to shift a lot of extra weight while aligning the mount, I would not add the counterweights until after the mount was aligned. I realised this was a bad move when, half way through the first rotation in Polemaster, the clutch gave way and the scope ended up hanging in what might be termed the inverse-home position.

Ignoring this omen, I proceeded to reconstruct the setup (this time with the counterweights) and got the mount aligned. In the final stage, the square and the star were right next to each other on the screen, so I settled for that as being good enough - PHD2 would tell me how good it actually was ... or so I thought.

Then APT/AT started playing-up. The program would run normally until it said that it had found a solution, then just hang. No syncing, no slewing, just a great deal of hanging. After a couple of goes at that I decided to forget it, just move the scope manually into position and sync myself.

OK, we are now just under an hour since I first sat down for my first attempt at polemaster. Any reasonable person would have seen the way the evening was going and just packed-up. But "reasonable" is not one of the adjectives most often used of me ...

Enter PHD2 for guiding - well, firstly calibration. The pixel size of my sxv guider is 9.8x12.6, so I took the average of these two and entered a pixel size of 11, which gave a calculation result of 1680. I now started getting a lot (and I mean a LOT) of results with a failed 'calibration sanity check' messages. Here are a selection:

Eventually, I started entering different figures into the 'calculation result' box, more or less at random, and finally ended up (more by luck than any sort of intelligent judgement) getting a successful calibration (or at least one that did not fail its sanity check).

Th figure used equated to having a pixel size of 6.5, which is the size of the pixels in the main camera rather than the guider. Coincidence, or is that what I am supposed to use?

So back to the imaging software and I was getting really poor results. Finally noticed that PHD2 was doing something weird. It was switching between two states at 1-2 second intervals:

I have no idea what was going on ... the skies were clear, no breeze to disturb the scope just at a total loss (if you'll pardon the pun). I did take a screenprint of the graph at this point, but, having nothing really with which to compare it, I have no idea whether it is good, bad, disastrous, ...

Now being some three hours since I started, and still being able to write what I had actually achieved on the front of a postage stamp without defacing it, I finally succumbed to the conclusion I should have reached three hours earlier, and packed-up.

I always try and find something positive to say about evenings like this, but I am finding it incredibly hard to do so on this occasion. But I suppose I can say that I have learned not to try to align the mount without the counterweights ...

Thanks.

[Akiainavas]

The PHD graph you attached looks really interesting - not only is the displacement quite large in both RA and DEC - they also seem to go the opposite way, not something I've encountered before. Also, some of the spikes seem really rather drastic.

An interesting lesson for all of us and certainly an answer to the 'what if' question many of us would either ask of think of at some point - thanks for sharing!

[wornish]

What version of PHD2 are you running.

I have had two wasted nights since I updated to the latest release at the weekend.  Version 2.6.2. was released late July and like a fool I updated to it.

I get the video blanking out every second or so and other weird behaviour.  So in frustration I went back to version 2.6.1 and it seems to work properly.

 

 

[Demonperformer]

I think it is 2.4.1, downloaded in Oct 2015. Only just getting round to trying to use it because only just getting PA sorted on the NEQ6. I will go looking for 2.6.1 and update if poss, giving that a try.

Thanks.

[Jonk]

2 hours ago, wornish said:

 Version 2.6.2. was released late July and like a fool I updated to it.
 

I've just updated mine - are there new bugs?

[wornish]

13 minutes ago, Jonk said:

I've just updated mine - are there new bugs?

I don't know, I was hoping someone here might have some info.

 

All I know is my ToupTek guide camera was working fine on 2.6.1 but would not work consistently on 2.6.2

I lost two good nights trying to fix it.  In the end I have now gone back to 2.6.1 and it works again.

[Demonperformer]

I have checked mine. It was 2.5.something. I have updated to 2.6.1 and will see if that performs any better.

Thanks.

[Freddie]

Your MnMo (the amount PHD has to see a star move before it will send a guide command) looks really high. I would normally expect to see 0.2 or something in that region. 1.65 is very high. How often was PHD actually issuing a guide command during the guiding run?

[Demonperformer]

To be honest, I do not really have any idea. What I can say is that this was one of the figures that the program decided upon for itself. If I can change it, I will have a go at bringing it down to 0.2 next time I try.

Do the other figures look ok, or is there something else I should alter? Also, if I reduce the MnMo, will this cause the others to change automatically in a way I would not want?

I really know very little about guiding settings and what effect they have - I was hoping that 'PHD' would really treat me like the 'D' that I am and do all the thinking for me!

Thanks.

[Thalestris24]

Hi

I'd recommend using the latest release of PHD2. Your calibration obviously isn't working properly and you won't get guiding working until calibration is sorted out. Do read through the PHD2 user guides. It may be that you were severely unbalanced but it's hard to say - I don't think I've ever seen a calibration attempt quite so variable! Perhaps you could list your equipment, particularly what imaging scope and what guide scope. You need to enter your guide scope focal length as well as your guide cam info into the step calculator. Before trying to calibrate, make sure you are polar aligned and then find a star at about 30 deg to calibrate on.

Louise

[Davey-T]

"Push Here Dummy" has gone by the wayside with PHD2, I'm still using PHD1 in the obsy on the "if it ain't broke" principal.

PHD2 has far too many buttons for dummies to push and needs much more time investing to get very good results once you figure it out.

Took me a few nights to get it working so keep it up, be worth it in the end, check all the usual things, starting with is the mount actually working properly when unguided ? you can turn off guiding and watch the PHD screen to see.

Not sure about Polemaster, some folk swear by it but I can't see what it achieves that can't be done with PHD and given the mechanical limitations of the mount how accurate is it possible to be ?

Dave

[Demonperformer]

Thanks for  the replies.

So that would appear to be 1 vote for v2.6.1, 1 vote for v2.6.2 and 1 vote for 'use PHD1 instead' .

Equipment list:
NEQ6 mount (aligned with polemaster)
8" SCT (it's the one that came with the 8SE mount)
A slimline OAG (not sure who made it) so no 'guidescope' as such and therefore no focal length
SXV autoguider head (the original, not the new bigger EX version)
SXV H9 camera as the main imaging beast (the autoguider runs through the main camera to connect to laptop & mount)

I realise a 2m scope is not necessarily the easiest thing to try to guide. I "recently" (in terms of the weather we have had) purchased a zenithstar71, which has so far not even seen first light (I like to try to get one new thing working at a time), but maybe using that might prove easier. Will have to check out all the connections/spacings for it.

How good is my PA with polemaster? Not totally sure, except to say that I can get 60s unguided subs with the SCT. I do see what you are saying about the limitations of the mount mechanics, which is why I have more or less taken to ignoring the last final 'tweaks' - when I first tried it, I found the corrections were so small that any attempt to make them made the alignment worse (which I consider not to be the object of the exercise!).

If PHD1 is a lot simpler to use, you don't by any chance have a copy of the installer I could pinch, do you??

Thanks.

[Davey-T]

Here's a link to PHD1

Dave

http://www.stark-labs.com/phdguiding.html

[Thalestris24]

1 minute ago, Demonperformer said:

Thanks for  the replies.

So that would appear to be 1 vote for v2.6.1, 1 vote for v2.6.2 and 1 vote for 'use PHD1 instead' .

Equipment list:
NEQ6 mount (aligned with polemaster)
8" SCT (it's the one that came with the 8SE mount)
A slimline OAG (not sure who made it) so no 'guidescope' as such and therefore no focal length
SXV autoguider head (the original, not the new bigger EX version)
SXV H9 camera as the main imaging beast (the autoguider runs through the main camera to connect to laptop & mount)

I realise a 2m scope is not necessarily the easiest thing to try to guide. I "recently" (in terms of the weather we have had) purchased a zenithstar71, which has so far not even seen first light (I like to try to get one new thing working at a time), but maybe using that might prove easier. Will have to check out all the connections/spacings for it.

How good is my PA with polemaster? Not totally sure, except to say that I can get 60s unguided subs with the SCT. I do see what you are saying about the limitations of the mount mechanics, which is why I have more or less taken to ignoring the last final 'tweaks' - when I first tried it, I found the corrections were so small that any attempt to make them made the alignment worse (which I consider not to be the object of the exercise!).

If PHD1 is a lot simpler to use, you don't by any chance have a copy of the installer I could pinch, do you??

Thanks.

Hi

You have a challenging setup! Your guide focal length will be your scope focal length - allowing for any reducer! Getting your scope balanced and accurately polar aligned will be important. Everything is much more crucial with longer focal lengths. It's also advisable to make a dark library and a bad pixel map for phd(2). If you can get 60s unguided, that's very good! Certainly your ZS71 will be easier...

Louise

[conspicuity]

I didn't understand all technicalities discussed here, but I recognized the frustration in the original account only too well - made me feel better. Thanks! I hope you reach a satisfactory solution soon.

I'll be sticking with PHD1, too.

[Demonperformer]

Thanks for your comments, guys - especially the link. I will get it downloaded and see how it goes.

[Demonperformer]

Downloaded PHD 1.14.2 from website and it totally failed to unzip .

Other zip files unzip quite happily, so not really sure what is going on (what else is new??).

Anyway, I have PHD2.6.1, which everyone seems to agree has been working properly, loaded on the lappy, so I will give that a go - when I can get the mount sorted so I can run it with a telescope again ...

Thanks.

 

[StuartJPP]

On 31/08/2016 at 10:34, Davey-T said:

Not sure about Polemaster, some folk swear by it but I can't see what it achieves that can't be done with PHD and given the mechanical limitations of the mount how accurate is it possible to be ?

Dave

PoleMaster is quick to use and accurate enough for a lot of people...I haven't used a polar scope since. I generally can't do drift alignment anyway due to my usual imaging locations not having southern views.

 

Demon...keep at it I am sure there will be a moment when you realise what is up. I would definitely do PA alignment with the counterweights attached and balanced. 

[libraryman]

You may not feel that staying with phd2 is beneficial to you but you will be giving away all the good diagnostic tools you need if you revert to phd1...

despite the difficulties of your set up, you will not achieve good guiding if you do not first of all achieve a good calibration and PhD 2 will assist you with that.

send your PhD logs to the PhD forum and Bruce will assist you. 

If you do stay with phd2 then upgrade to the latest Dev ver: dev 11.     I've used it from launch and it works..it also has all the camera compatibility you are likely to need.

 

Ray

[Demonperformer]

2 hours ago, libraryman said:

If you do stay with phd2 then upgrade to the latest Dev ver: dev 11.

I have 2.6.1 installed now (PHD1 hav ing failed to load - see my last post), but have no idea if it is dev11 or not. Had a look through the PHD2 website and cannot find any reference to different "dev" versions.

I will have a look at the PHD forum.

Thanks.

[uhb1966]

Hello Dear Demonperformer,

i had just the same problem the last night i tried to image, and it was my first try with V2.6.2. I had a significantly older version in use before. However, i tried to calibrate at a very high latitude (around 80deg alt). I read the documentation which stated that calibration is best exercised between +-30 degrees alt. That being said, i will try the older version (261) as well next night.

 

[Demonperformer]

I was doing my calibration right on the celestial equator (alright, 20' off, centred on 59 Ser), which from my latitude would put it about 40 degrees altitude. Maybe next time I will try something a little nearer the horizon, but if I go too far, I end up in the glare of the streetlights.

I have decided that I am going to work initially with the ZS71, as the advice is that this will be easier. However, I need to get an adapter sorted so that I can connect the scope/reducer to the OAG. I will also use 2.6.1, for which there is a manual online. I'm not sure whether it is "dev 11", but I couldn't find a download that specified that, so I will have to work with what I have.

This is obviously not going to be a straightforward exercise, but (like so many other things) one that will come with practice. As I was always taught, "The only place success comes before work is in the dictionary".

In the meantime, while I sort out an adapter, I am having some fun with widefield.

Thanks.

[Thalestris24]

1 hour ago, Demonperformer said:

I was doing my calibration right on the celestial equator (alright, 20' off, centred on 59 Ser), which from my latitude would put it about 40 degrees altitude. Maybe next time I will try something a little nearer the horizon, but if I go too far, I end up in the glare of the streetlights.

I have decided that I am going to work initially with the ZS71, as the advice is that this will be easier. However, I need to get an adapter sorted so that I can connect the scope/reducer to the OAG. I will also use 2.6.1, for which there is a manual online. I'm not sure whether it is "dev 11", but I couldn't find a download that specified that, so I will have to work with what I have.

This is obviously not going to be a straightforward exercise, but (like so many other things) one that will come with practice. As I was always taught, "The only place success comes before work is in the dictionary".

In the meantime, while I sort out an adapter, I am having some fun with widefield.

Thanks.

Hi

You can get dev snapshots here v2.6.2 is the latest release. The guiding analysis tutorial pdf might be useful.

Louise

[Demonperformer]

Thanks.

As others have indicated problems moving from 2.6.1 to 2.6.2, it seems sensible to try to get it working with 2.6.1. Ray suggested using dev 11, but that is not listed on the link, but thinking about it I would guess that their download link for 2.6.1 would contain the latest version anyway, so I won't worry too much about it.

I have downloaded and will peruse and digest the tutorial pdf.

Thanks

[uhb1966]

Hello Demonperformer, just had another go with 2.6.2 last night. Calibrated on a star at +3 degrees, it worked this time.