PHD2 2.6.11 won't guide my rig - had to roll back to 2.6.10

[Geoffrey Lewis]

Hi Bruce / Andy,

I was prompted to update my PHD2 to the new full relaese 2.6.11 at the start of my imaging session this evening, which I did, but immediately found it unusable, sorry.

After a bit of diagnosis the problem is that the Min HFD is now fixed at not less than 1px, but my rig frequently produces stars with HFD below that and fairly often below 0.5px, so I then set Min HFD to 0 (I'm definitely guiding on a star using PHD2's auto select with multi star option). The consequence tonight was that I had continuous lost stars in a crystal clear sky, with the only solution being to roll back to 2.6.10, where I could set a lower min HFD.

I know the frequent advise not to leave this setting at zero, but 1.0 just isn't ging to work for me, so unless I have the option to set lower, then I'm either going to have to defocus my guide camera, or stay on the older version.

FYI I'm guiding through the integrated OAG of my old QSI583 using a Lodestar X2 binned x2.

Best regards,

Geof

[Bruce Waddington]

Hi Geoff, sorry you ran into trouble.  Can you send me the debug log file from the failed attempt to find stars?

 

Thanks,

Bruce

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[Geof Lewis]

Hi Bruce,

Thanks for getting back to me so quickly. I've not used the upload tool previously so I hope this includes what you need.

https://openphdguiding.org/logs/dl/PHD2_logs_ffv5.zip

Regards,

Geof

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From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Bruce Waddington <bw_m...@earthlink.net>
Sent: 24 February 2022 22:30
To: open-phd...@googlegroups.com <open-phd...@googlegroups.com>
Subject: RE: [open-phd-guiding] PHD2 2.6.11 won't guide my rig - had to roll back to 2.6.10

 

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[Geof Lewis]

Hi Bruce,

Well that seems to only include the guide session that I've just completed with the rolled back v2.6.10, so how do I get the log files with v2.6.11? Do I need to reinstall the latest version to see those? However, I think that this debug log will show the much less than Min HFD of 1.0 that I usually experience with my 4" APO configuration.

Regards,

Geof

---

From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Geof Lewis <geof...@hotmail.com>
Sent: 24 February 2022 22:35
To: open-phd...@googlegroups.com <open-phd...@googlegroups.com>
Subject: Re: [open-phd-guiding] PHD2 2.6.11 won't guide my rig - had to roll back to 2.6.10

 

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/AS8P194MB13502130C78CE3D09266AEEDA03D9%40AS8P194MB1350.EURP194.PROD.OUTLOOK.COM.

[Bruce Waddington]

The debug log file should contain any sessions you ran “last night” regardless of release number.  Just to be clear, I’m talking about the debug log, not the guide log.

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[Geof Lewis]

Thanks Bruce,

I believe the upload includes both. I opened the debug log and saw the header stated 2.6.10, which got me concerned it was the wrong file, but I then did a lost star find and found all those lost star events in the period between 19:11 and 19:38, which is probably about when I rolled back to 2.6.10. I then performed a search for the string HDF and see very many examples where that is below 1.0 after I restarted guiding through to the conclusion of my imaging session.

Regards,

Geof

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Sent: 24 February 2022 22:49

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[Bruce Waddington]

Yes, the log data you uploaded is what I want but I don’t quite understand the problem yet.  Here is the list of guide stars that were found, including their HFD values:

 

19:12:07.094 00.000 5512 Star::Find(15, 59, 230, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.094 00.000 5512 Star::Find returns 1 (0), X=59.43, Y=229.85, Mass=74865, SNR=177.5, Peak=15750 HFD=2.1

19:12:07.094 00.000 5512 Star::Find(15, 219, 111, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.094 00.000 5512 Star::Find returns 1 (0), X=218.94, Y=110.88, Mass=28956, SNR=103.4, Peak=7681 HFD=2.2

19:12:07.094 00.000 5512 Star::Find(15, 335, 207, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.095 00.001 5512 Star::Find returns 1 (0), X=335.03, Y=206.69, Mass=22700, SNR=91.2, Peak=6223 HFD=2.2

19:12:07.095 00.000 5512 Star::Find(15, 259, 159, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.095 00.000 5512 Star::Find returns 1 (0), X=259.33, Y=159.31, Mass=23433, SNR=93.2, Peak=7161 HFD=1.7

19:12:07.095 00.000 5512 Star::Find(15, 315, 268, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.095 00.000 5512 Star::Find returns 1 (0), X=314.67, Y=267.63, Mass=20170, SNR=82.9, Peak=5852 HFD=1.8

19:12:07.095 00.000 5512 Star::Find(15, 126, 142, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.095 00.000 5512 Star::Find returns 1 (0), X=126.08, Y=141.44, Mass=8239, SNR=47.9, Peak=4117 HFD=2.1

19:12:07.095 00.000 5512 Star::Find(15, 110, 69, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.095 00.000 5512 Star::Find returns 1 (0), X=109.97, Y=69.23, Mass=9194, SNR=51.9, Peak=4259 HFD=2.3

19:12:07.095 00.000 5512 Star::Find(15, 151, 67, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.095 00.000 5512 Star::Find returns 1 (0), X=151.43, Y=67.11, Mass=8174, SNR=47.0, Peak=3923 HFD=2.1

19:12:07.096 00.001 5512 Star::Find(15, 243, 204, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=243.20, Y=203.42, Mass=5255, SNR=34.7, Peak=3548 HFD=1.9

19:12:07.096 00.000 5512 Star::Find(15, 329, 120, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=329.11, Y=119.63, Mass=2613, SNR=22.1, Peak=2939 HFD=2.3

19:12:07.096 00.000 5512 Star::Find(15, 261, 27, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=261.19, Y=26.80, Mass=1395, SNR=16.0, Peak=2929 HFD=1.7

19:12:07.096 00.000 5512 Star::Find(15, 308, 152, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=308.13, Y=152.26, Mass=1720, SNR=17.0, Peak=2878 HFD=2.3

19:12:07.096 00.000 5512 Star::Find(15, 348, 219, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=335.03, Y=206.69, Mass=22700, SNR=91.2, Peak=6223 HFD=2.2

19:12:07.096 00.000 5512 Star::Find(15, 36, 262, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=35.67, Y=261.63, Mass=1142, SNR=11.8, Peak=2821 HFD=1.7

19:12:07.096 00.000 5512 Star::Find(15, 63, 192, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.096 00.000 5512 Star::Find returns 1 (0), X=50.68, Y=207.13, Mass=11510, SNR=60.5, Peak=3290 HFD=2.2

19:12:07.097 00.001 5512 Star::Find(15, 81, 62, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.097 00.000 5512 Star::Find returns 1 (0), X=96.54, Y=47.95, Mass=8976, SNR=52.3, Peak=3856 HFD=2.2

19:12:07.097 00.000 5512 Star::Find(15, 307, 30, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.097 00.000 5512 Star::Find returns 1 (0), X=307.45, Y=29.93, Mass=1124, SNR=12.2, Peak=2823 HFD=2.3

19:12:07.097 00.000 5512 AutoFind: finding best star pass 1

19:12:07.097 00.000 5512 Star::Find(15, 59, 230, 0, (0,0,0,0), 1.5, 65000) frame 3

19:12:07.097 00.000 5512 Star::Find returns 1 (0), X=59.43, Y=229.85, Mass=74865, SNR=177.5, Peak=15750 HFD=2.1

 

So, 12 stars in the list with HFD values in the range of 1.7 to 2.3.  But as guiding began, you started getting lost-star events because of HFD values that were much smaller as you say.  Of course, you also got quite a number of lost star events running 2.6.10 right after that.  It seems like there is a large amount of fluctuation here.  Can I ask, do you really need to bin the camera?  That’s giving you a very coarse image scale and the guiding results are not what I’d expect from an AP mount.  I’m not opposed to making changes here but I’d like to understand the problem a little better.

 

When you get lost-star events, PHD2 automatically saves the problem guide images in separate folders, all in the same directory as your normal log files.  If you look at my response in this thread, you’ll find more info on how these folders are named.  If possible, I’d like to see your lost-star images from the time period around 19:14 – 19:15 on 2/24. 

 

https://groups.google.com/g/open-phd-guiding/c/2VWh3-UDnDI/m/9_gSKujdBQAJ

 

 

Thanks.

Bruce

 

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of Geof Lewis

Sent: Thursday, February 24, 2022 2:35 PM
To: open-phd...@googlegroups.com

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[Geoffrey Lewis]

Hi Bruce,

I'm not sure if this will work, but here are those lost star event images.

[Geoffrey Lewis]

Sorry Bruce,

I inadvertently hit 'post' before adding all the images. Unfortunately it seems that I can only add them one by one. I've added a few more here, do you need more than these?

I bin the camera as that is the recommendation from SXpress for their Lodestar cameras. I've never tried it unbinned.

Regards,

Geof

[Bruce Waddington]

Thanks, this is plenty of images.  Let me stare at them awhile…

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[Geof Lewis]

Thanks Bruce,

You commented about my poor guiding in this session not being what you'd expect from an AP mount and yes, it was rubbish, but I've got so frustrated at lack of clear skies that I continued imaging in 34mph wind gusts, something that I would never normally do. However, I don't believe the strong winds were a significant factor in the low HFD values during this session, as these are something that I've noticed for years with this configuration, which I've previously 'fixed' by selecting a lower or even zero min HFD value. In this session my guiding RMS was between 1" to over 2", not something that I would usually entertain. My session from 2 nights ago, before I tried to upgrade PHD2 was approx 0.62" total RMS over 4 hours during which HFD values were frequently below 1px. This is pretty typical guiding performance for this configuration.

Regards,

Geof

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From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Bruce Waddington <bw_m...@earthlink.net>

Sent: 25 February 2022 00:09

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[Brian Valente]

Geof what mount do you have? encoders?

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Brian 

Brian Valente

portfolio brianvalentephotography.com 

[Geof Lewis]

Hi Brian,

Encoders, I wish 😉. I have a 2007 model AP1200GTO CP3 with an old chip in it. I bought it pre-owned about 7 years ago and after a few pilot errors, which Bruce help me solve with the team at AP, it's proved to be a fine investment. I've considered updating the chip to allow PemPro to create a PEC curve and APCC, with all the functionality that brings, but really, I'm happy to guide it as is. It's a brute of a mount and barely knows that I have a C14 on it ,with the 4" TSAPO100Q piggy-backed on that.

Regards,

Geof

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Sent: 25 February 2022 00:51

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[Bruce Waddington]

Hi Geoff.  I think it’s just a property of the guide camera, so that is what it is and we need to make a change that will let you do your thing.  I need to talk to Andy and see how we want to handle this from a release update point of view.  I assume you’re ok running on the prior release at this point but if not I can provide you with an updated binary that will avoid this problem.  Just for grins, if you have time sometime down the road, I would be interested to see what happens if you try running the camera un-binned while using the native driver.  If you decide to try that, be sure to create a new PHD2 profile so you don’t screw up what you have.

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[Geof Lewis]

Hi Bruce,

Yes, I’m totally fine with running on the old release. I’m naturally risk averse, so usually only upgrade on full releases, though from time to time you have persuaded me to install a development release.

I can certainly try running the guide camera unbinned, but I’m sure that the recommendation is to bin it.  That said though, it wouldn’t be the first time that I’ve convinced myself of something that I later couldn’t back up. However, wouldn’t that likely make it more difficult to identify suitable guide stars? Perhaps I’d be ok unbinned with the 4” TSAPO100Q, but I’ll definitely need to bin it with the C14, as sometimes I already struggle to find guide stars through the QSI OAG when imaging with that.

Regards,

Geof

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From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Bruce Waddington <bw_m...@earthlink.net>

Sent: Friday, February 25, 2022 2:17:07 AM

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[Brian Valente]

Hi Geof 

Is there a general recommendation to bin the lodestar x2?

i understand about the C14, but geeze the pixels in the lodestar are pretty big already. I hesitate to bin mine

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[Bruce Waddington]

Usually, you bin a guide camera for one of two reasons:

1.       You are trying to improve the sensitivity because guide stars are scarce

2.      You want to avoid over-sampling, in order words having a guider image scale that is too small

The first point would apply to you for the C14 and I think your star sizes there are probably larger than 1 pixel.  On your refractor, binning results in an image scale of over 5 arc-sec/px which is pretty coarse, and it could be the limiting factor with your mount.  So I’m suggesting you try running un-binned only on the refractor and, again, getting your star sizes up to a more normal range.  It’s just a test, something we can perhaps learn from.

 

The recommendation to “always bin” doesn’t make much sense to me but I don’t know why the recommendation was made. 

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[Bryan]

Geoff

Have you tried increasing the guide camera gain to see if it picks up more stars for PHD2 in C14 mode?

Bryan

[Geof Lewis]

Hi Brian,

I’m not aware of any camera gain setting for the Lodestar X2. If you know his I can do that I’d definitely try it.

Regards,

Geof

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Sent: Friday, February 25, 2022 7:08:31 PM

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[Geoffrey Lewis]

Hi Bruce,

Yes, I can do some testing without binning with the TSAPO, but that will have to wait as I'm working on a project with limited sky time and don't want to waste what little clear skies I get. The Lodestar X2 manual states, 'The preferred guiding mode is 2x2 binned, as this gives both fast downloads and high sensitivity without any 'interlacing' issues.' I have no idea what interlacing issues are, or what effect that would have on the camera's performance, but as the recommendation is coming from SXpress, it seems the correct thing to do and I've never questioned it.

Regards,

Geof

[Geof Lewis]

Hi Bruce,

So I got to do the Lodestar X2 unbinned test tonight, after I completed the session on my current target. I use the wizard to build a new profile, then created dark frames and a dark pixel map.  I used the drift align tool to slew to where I could run a good fresh calibration, then slewed over to the M95 triplet in Leo and ran a capture sequence of 6x10m luminance frames. I had absolutely no issues with guiding. Star HFD fluctuated between about 2.2 to 2.9 px which is much better than I was getting at Bin2. Total RMS <0.6” (0.2px) which is about as good as I get.

This was all using the old v2.6.10, with min HFD set to 1.5px. Next step is probably to run a much longer imaging session, then upgrade to V2.6.11.

Thanks for jumping on my issue so quickly and making a recommendation different to the camera manual. You really do know what you’re talking about 😉.

Many thanks,

Geof

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[Geoffrey Lewis]

Hi Bruce,

I had a couple of email exchanges with Terry on the SXpress user forum today, so wanted to share what he told me about binning the Lodestar X2 camera. It's a couple of fairly long threads, but might prove usefu to you and Andy as well as other Lodestar X2 users guiding via PHD2. Here goes...

From Terry...

I see that the subject has been covered pretty well already, but I’ll clarify the bit about 2x1 binning. As you know, the Lodestar uses an ‘interlaced’ CCD, with two active fields of pixels, composed of the ‘odd’ lines and the ‘even’ lines. Two separate ‘readout pulses’ control which field will be transferred to the readout registers, so you can request the even field, the odd field or both together, by sending different readout pulse combinations. There are two options for getting the full vertical resolution – (1) you can make two equal exposures in succession and download the even and odd fields separately, then combine them in software, or (2) make a single exposure and do two immediately successive downloads (say even, then odd), with software combination of the data, as before. Method 1 is time wasteful, but gives uniform exposures of the even and odd fields, method 2 is more efficient, but the even and odd field exposures are going to be unequal, as the second field is still exposing as the first field is being downloaded. Tweaks in software can equalise the fields in method (2), but there can still be some ‘interlace patterning’ in the final image.

 

As the Lodestar is primarily a guide camera, the highest sensitivity and fastest download time, tend to be the most important factors and so we consider that full resolution frames are not critically important. This is why the default in PHD2 is 2x1 binning – this dumps both the even and odd fields into the readout simultaneously and reads out much faster than either of the fully interlaced modes. It also doubles the effective sensitivity. The only sacrifice is in the vertical resolution of the frame, but this can be oriented so that it is in the Dec direction – so keeping the RA direction at full resolution. This is generally a very good compromise, as Dec corrections are usually very small and slow, but the RA corrections are often and rapid action is necessary. You do have the option of using 2x2 binning, which is slightly faster and even more sensitive, but this will degrade the RA precision somewhat, so it is best for long focus optics, or AO guiding, where speed is very important.

 

I don’t really recommend using the high resolution mode (method 2) for general guiding purposes, but, of course, it can be used. In most cases 2x1, with the RA axis horizontal, is optimum.

 

Regards,

Terry

From me...

Hi Terry,

Thanks for the detailed explanation about binning the Lodestar X2. I never knew about the recommended orientation of the guide camera chip to the RA and Dec axes, so never did that other than by accident. I have my lodestar permanently fixed to the OAG port of my QSI583 camera, which gets rotated to different positions, in order to best frame the target, so consequently the guide camera orientation changes with that. I mostly use 2 different orientations, 90 degrees apart so that I’m not having to shoot lots of different flat frames. These 90 degree positions are broadly aligned with the RA and Dec axes, so sometimes the Lodestar chip will be orientated as recommended, but then on other times the opposite is true. Maybe the Lodestar X2 isn’t a good choice of guide camera for my configuration.

I’m also not aware of the 2x1 bin option in PHD2, I believe that I only see Bin 2, which I thought was 2x2. Please may I copy your explanation of the Lodestar X2 interlace operation and binning recommendation over to the Open PHD2 forum to ask them to clarify what PHD2 expects?

BTW I tried using the camera unbinned last night and it seemed to work perfectly well, but maybe I’m just unaware what the effect would be.

Best regards,

 

Geof

From Terry....

Hi Geof,

 

The 2x1 configuration is the default in PHD2 – you don’t need to set it in the software. ‘Bin 2’ is 2x2 binning, if you want to use that.

 

I wouldn’t be concerned about the variable orientation – it probably has only a small effect on the guiding accuracy, but, of course, high resolution mode will avoid any changes due to rotation (as will 2x2 mode). As you have seen for yourself, it works fine with all the different settings.

 

Best regards,

Terry

Bruce,

The 2 main takeaways for me were that...

• what I thought was unbinned in PHD2 (the default) is in fact 2x1 binning. Please can you confirm this.
• Terry states that the camera should work fine in any orientation using it's default 2x1 configuration, so this is how I will run the camera with the 4" TSAPO100Q in future.
• Bin 2x2 is also a good solution and I will continue to use that when imaging through the C14 as it will more likely find suitable guide stars and will be a better match between guide camera and imaging camera image scales, plus is unlikely to run into the min HFD ,1px problems that I experienced with my 4" TSAPO100Q under v2.6.11.
  

Many thanks for your help with this. Are there any final thoughts from you and/or Andy before I upgrade?

Best regards,

Geof

[Bruce Waddington]

Hi Geof.  Yes, this is familiar ground for us.  I didn’t want to take you into the weeds of interlaced sensors and the programming options for dealing with those.  We don’t think those kinds of implementation details are important for users to know about.  To cut to the chase, let’s go back to your final list of conclusions:

 

Bruce,

The 2 main takeaways for me were that...

·        what I thought was unbinned in PHD2 (the default) is in fact 2x1 binning. Please can you confirm this.

Yes, that is correct.  Most users aren’t familiar with asymmetric binning and we consider this an implementation detail that doesn’t belong in the UI.

·        Terry states that the camera should work fine in any orientation using it's default 2x1 configuration, so this is how I will run the camera with the 4" TSAPO100Q in future.

Yes, you should ignore this hypothetical problem.  In any case, it isn’t practical to think you can align the axes with an accuracy that is equivalent to computing star positions at the level of 0.05 to 0.1 px. 

·        Bin 2x2 is also a good solution and I will continue to use that when imaging through the C14 as it will more likely find suitable guide stars and will be a better match between guide camera and imaging camera image scales, plus is unlikely to run into the min HFD ,1px problems that I experienced with my 4" TSAPO100Q under v2.6.11.

Yes, you will almost certainly want to bin the camera 2x2 on the C14 for a variety of reasons.

I don’t think any of this “deep dive” changes the recommendations I gave you earlier and as long as you’re willing to try the un-binned approach on your refractor, you should be good to go with 2.6.11.  But by all means report back if you run into problems.

Regards,

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/ea489b74-0fb0-4527-b475-e1a357dacb99n%40googlegroups.com.

[Geof Lewis]

Thanks Bruce,

Yes, your recommendations were good all along, so sorry if my 'deep dive' went too far. However, for me it was important to better understand what the issue was that led to the Lodestar X2 manual's recommendation to bin the camera. I had no knowledge that the default setting in PHD2 was the asymmetric 2.1 binning, which according to Terry Platt of SXpress IS the preferred mode of operation for the camera.

I believe that there may be other PHD2/Lodestar X2 users that, like me, also do not realise that they do not need to select the Bin 2x2 option in PHD2 to optimise the camera's performance. Hence, if my research helps clarify that misunderstanding for even one other person, then it was worthwhile.

I have not upgraded yet, but have just completed a 3.5 hour session on my current target, using my new Lodestar (default Bin 2x1) PHD2 profile and it ran as sweet as a nut, so I will upgrade at the start of my next outing.

Again, many thanks for your help.

Regards,

Geof

---

From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Bruce Waddington <bw_m...@earthlink.net>

Sent: 26 February 2022 22:29

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/000401d82b60%2452644f30%24f72ced90%24%40earthlink.net.

[Bruce Waddington]

No worries, Geof,  I wasn’t trying to dissuade you from getting into the details.  It’s all good, hope your imaging continues to go well.

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/AS8P194MB135026E13D533E93A9476A6DA03F9%40AS8P194MB1350.EURP194.PROD.OUTLOOK.COM.

[Steve Milne]

I'm intrigued to have found this thread.  I have been having problems guiding myr remote rig since late February 2022.  I have a 1015 mm focal length scope, a QSI 690 with OAG, and a Lodestar X2 camera.  After three years without any guiding issues, I began to experience frequent 'Star Lost low HFD' messages.

I tried multiple things to fix this - including replacing USB cables and (most recently) swapping out the Lodestar X2 for an older (non-X2) Lodestar.  My first opportunity to try the replacement Lodestar was last night - but within 15 minutes or so I was getting the low HFD messages again. 

After finding this thread, I installed v2.6.10.  I set the min HFD setting to 0.5 (as per the OP).  And I had a successful imaging run with no more lost star messages.  Whilst the 'binning' conversation is interesting, it does seem that (at least for me) something broke during the update from 2.6.10 to 2.6.11.  I was binning over the last 3 years with this rig.  Whilst I learn that this may not be optimal, I was quite happy with the guiding and the images I was getting.     

[Bruce Waddington]

Nothing "broke" in the 2.6.11 release, we were dealing with a long-standing problem of people running with min-hfd values of zero.  If your stars are producing HFD values of 0.5 px or less, the centroid calculations are likely to be sub-optimal. The rationale for binning the camera at these image scales makes no sense for the way PHD2 actually works unless you simply can't find any usable stars.  If you stop binning the camera, you will get star sizes that will result in more accurate centroid values.  If you don't want to do this, you can upgrade to the 2.6.11dev1 release and continue in the way you have before.

Bruce