Disconnect Non-responsive Camera after (seconds)

[mark matzner]

Hi Group,

Could you tell me what is the purpose of this control feature?

I have been having a deuce of a time finding guide stars recently (that is PHD2, 2.4.Orc3 and my Lodestar), and I wonder if adjusting this would prove of some benefit.

Thanks for your help,

Mark

[Andy Galasso]

Mark,

The non-responsive camera timeout setting is irrelevant for finding guide stars. It has to do with PHD2 detecting disconnected or otherwise unresponsive cameras. The only reason to change this would be if PHD2 is incorrectly reporting that your camera is disconnected. This is an issue for the SBIG SGP API Guider ASCOM driver which shared access to the SBIG camera's guide chip and imaging chip and looks to PHD2 as if the guide camera is unresponsive during the download of the image from the main chip. In that case the parameter is used to prevent phd2 from thinking the camera is disconnected.  Unless you are using the SBIG SGP API Guider ASCOM driver there should be no need to change that setting.

If you are having trouble finding a guide star, the main things to consider are:

  1. make sure you are in focus. Slew to an area of the sky where there are lots of stars, and check your focus.

  2. if the area of the sky where you want to guide lacks bright guide stars, you have to increase your exposure time to pick up the dimmer stars.

Are you using an OAG or a guide scope?

Andy

[mark matzner]

Hi Andy, thanks for the quick reply.

I am operating a 12"LX200 Classic including a Starizona f/7.5 corrector.  The measured focal ratio is f/7.16, yielding a focal length of 2182mm at the imaging camera (Atik 383L+mono).

  The setup uses a Hutech OAG5 off axis guider and Lodestar guide camera.  I have a 0.5x reducer directly in front of the Lodestar resulting in further focal ratio reduction to 1091mm (i.e. 2182 x 0.5) for the guide camera.

The default guide camera exposure duration is 2.0 seconds.  I have tried 3.0 seconds during this lack of guide stars with no obvious improvement.  I'd be happy to go higher if that would improve my chances for success.

The guide camera setup yields "in-focus" stars at the same point as does the imaging camera.  It's interesting to watch the guide star (when there is one) go in and out of focus as SGPro is doing its AF routine.

My current target is M33, although several targets in the same general part of the sky seem to be lacking any guide stars.

Typically when there are guide stars, there IS usually just one to choose from (as far as I can see), and the star is rarely anywhere but along an edge of the guiding FOV.

I do know that PHD2 and SGPro can play nice together, and up until recently, PHD would locate and latch onto a guide star as intended.

However, I have witnessed several instances (this time) where PHD ignores the one available guide star or fails to find it.  During these times, even intervening manually does no good.  I've also witnessed PHD picking a spot where I swear there is no star and be perfectly happy to guide from there.

And if no guide star is found in short order, then SGPro is (very) quick to abort, and precious time is lost waiting on the imaging camera to cool down again.  NOTE:  I believe I can avoid this behavior with a menu choice in the Camera section of SGPro's Control Panel.

Right now I'm a bit discouraged, since there's not much point in having an automated system, If I have to be there at each critical junction.

Thanks for your help, sorry for the long post.

Mark

[Andy Galasso]

Mark,

If you come across the situation where you think phd2 failed to choose the best guide star, please post the camera frame and PHD2 debug log.  On the menu, select File => Save Image to save the image.

PHD2 will refuse to select a star that is very close to the edge, so you may need to frame your target or rotate your camera so the guide star is not so close to the edge.

Just grasping at straws, but is it possible there is some vignetting somewhere that is preventing light from reaching the OAG and/or guider chip? Or perhaps the lodestar CCD orientation is not right, i.e., is it in a "landscape" or "portrait" orientation relative to the pick-off mirror? I think it should be "landscape".   When you go to an area of the sky with lots of stars, do you see many stars in the guider FOV?

Andy

[mark matzner]

Andy,

I'm sending via DropBox all (?) of the PHD2 files from the night of Nov. 30th.  Sorry for the mess, but there was a bunch of start/stop while I tried to get the guiding going.

There is one screen shot JPEG of the example of peculiar guide star selection.  This is "Star Refusal1-1".  I had touched on this behavior in my previous post.

1.  There is no star (that I could see) at the location where PHD2 (2.4.Orc3) is guiding.  

2.  PHD2 only chose that location after previously failing to find a star (about) three times.

3.  The star at slightly above mid level on the left side is REAL.

4.  Note that the real star and the guiding location are situated about the same distance from the edge of the FOV.

5.  All other bright spots are hot pixels.

6.  I tried several times to get PHD2 to guide on the "real" star, but it refused.

7.  The time stamp on the JPEG is 6:29pm, Sunday November 30th.  So I believe there should be a debug file that matches up with this time.

8.  You've got me on the landscape vs portrait setup.  I would assume portrait.

9.  I can verify there are patches of sky where multiple guide stars show up.  It appears the area around M33 is just guide star poor.

10.  Things that may affect finding a guide star include light pollution, moon, maybe some high overcast clouds, early in the evening vs. later.  There was one example where PHD could not find a guide star.  When I came back to that same panel 2 or 3 hours later it found one.  But see item#2 (above).

Just out of curiosity, what are the AutoSelectFail.FIT files?  Are these screen shots of the failed attempts?

https://www.dropbox.com/sh/gshnrnobhwpjklr/AAAJ7rYGVf8s7cRycs530P-4a?dl=0

Thanks for your help and patience.

Mark

[bw_msgboard]

Hi Mark.  I think maybe I’m missing some context here – are you relatively new to guiding at long focal lengths?  The reason I ask is because of the First Law of Local Focal Length imaging: there are no guide stars. J  I don’t see any mention in your messages of a rotator.  Are you doing that by hand or not doing it at all?  If the latter, you can expect to be out of luck more than ½ the time.  I image at 2500 mm focal length with the same OAG you have, and I have to rotate the guider assembly more than ½ the time unless I’m working in star-rich areas near the galactic plane.  I don’t even bother to look with exposures less than 5 seconds, and I’ve sometimes had to go to 10 seconds.  The little screw-on focal reducer you have on the Lodestar will only expand your FOV if the light cone from the pick-off prism is larger than the Lodestar chip – I don’t know if it is.  Otherwise, it will only boost the apparent brightness of a guide star if you can find one, which is still a good thing.  Are you using a planetarium program to map this out ahead of time?  I use the TheSky6, which works well.  You construct field-of-view indicators for both the main chip and the guider, being careful to get the offset between the two chips right.  Then you can center your target on the main chip FOV and look in the annular guide region to see where a suitable star will be.  As I said, I haven’t failed at being able to find one so far, but I almost always have to rotate the guider to pick up a usable star.  

 

I think you may have somewhat unreasonable expectations for unattended operation with this set-up.  The imagers I know who do this successfully all have software-controlled rotators and use dedicated automation software.  With the latter, guide stars are chosen from a catalog, the instrument package is rotated to the correct position, and the guiding software is told where to lock.  I’m not familiar with SGPro but I wonder if it can do all this.  In any case, I think you’ll need to invest some significant hands-on time getting this sorted out before you can hope to automate it.   All of that said, if PHD2 is refusing to accept a usable star, that’s a different matter and needs to be resolved by us…

 

Good luck.

Bruce W.

 

 

 

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[mark matzner]

Hi Bruce, 

Thanks for the reality check.  I needed that.

I'll respond in rough order to your points and see if there's a go-forward path I can take.

I started with my second-hand 12"LX200 Classic in 2005 doing planetary work.  Graduated to a  couple of DSLRs and did guided imaging using a 80mm Orion Short Tube and then 80mm TMB refractor, video cam and Guide Dog guiding software (remember that?).  The scope was tripod mounted in the back yard on a DIY wedge.  Somewhere along the line I started using PHD Guiding software.  I think Guide Dog was no longer supported.

Moved onto a Mitty wedge and completed an Exploradome observatory for permanent installation in 2009.  Since then I have added a Lodestar camera, Hutech OAG5, Atik 383L+mono, Atik EFWS filter wheel, Starizona F/7.5 SCT corrector, Starizona MicroTouch Auto-focuser and Sequence Generator Pro (image capture software).

FWIW, my guiding with the OAG5 was initially at 1524mm.  That was with the Meade at native focal length and the guide camera looking through the 0.5x reducer.  I took the chance last year on the Starizona F/7.5 SCT corrector and could not be happier.  As mentioned in my previous post, this device yields a f/7.16 reduction.  To equate the previous imaging reducer (Meade F/6.3) with junk would be giving junk a bad name.

So there's my C.V., and now on to your points:

1,  Rotator -- I do not have one and hoped I did not need one. (see item 5)

2.  Guide camera exposure --  I typically use 2 seconds.  I will give 5 seconds a try and maybe even 10 seconds.  It sounds like this should improve my situation.

3.  Guide camera 0.5x reducer -- I've not tried a setup without this reducer.  Intuitively, the situation should be better with it, but I may try without if the exposure extensions do not help.

4.  Unreasonable expectations?  Well, probably.

5.  SGPro is a powerful  software and might very well have rotator programming capability for guide stars.  I simply don't know, never intending to use or need that feature.

6.  I have had some success in all night imaging with multiple targets un-attended.  However those events are in the minority, so I've spent quite a bit of time baby sitting the system.  Right now the main aggravation seems to be the software's inability to find or re-find the guide star.  And 'till this group of targets, this problem has not been the problem.

FWIW, what I think I know about PHD2 is that folks here have spent quite a bit of time making it very compatible with SGPro.

Thanks again for your input.

[Andy Galasso]

Hi Mark,

I have some comments in addition to what Bruce has said.

Next time you see something unexpected, be sure to do File => Save Image, then we will have the actual data from the camera to inspect. The screenshot is only marginally useful since it only hints at the actual data from the camera.  

>> Just out of curiosity, what are the AutoSelectFail.FIT files?  Are these screen shots of the failed attempts?

Whenever phd2 is requested to auto-select a star (in your case by SGP), and the auto-select fails, phd2 saves the camera frame (the actual data in fits format, not a screenshot) to the log folder.  The last 10 auto-select failure files are retained.

The auto-select fail files you uploaded all look like clouds to me, so that's a legitimate reason to fail.

>> There is no star (that I could see) at the location where PHD2 (2.4.Orc3) is guiding.

Down in the bottom-left corner of the main PHD2 window you can see m=3449 SNR=8.2.  That means phd2 is guiding on a star with mass 3449 and SNR 8.2, which is actually not a bad guide star (not great, but not too bad.) PHD2 can guide on stars with SNR > 3.0.  Sometimes it is hard to see the star behind the crosshairs. View => Display Star Profile is a useful tool to "zoom-in" and see the star that phd2 is guiding on.

Andy

[bw_msgboard]

You have a nice set-up and it looks like you’ve made some good upgrades.  FWIW, I followed a somewhat similar path using a 10-inch Meade LX200GPS for about 7 years.  So I certainly didn’t want to discourage you – just trying to help you avoid some frustration. J   You actually *do* have a rotator, albeit the “manual” kind – just like me.  The OAG-5 has rotatable interfaces on both sides, so you can rotate the camera assembly by just loosening the thumbscrews.  As I said, I have to do that most of the time to find guide stars.  But I can’t imagine trying to do this without a planetarium program that would give me the correct answer ahead of time.  I’ve attached two screenshots from TheSky6 which show what I did on my last target, NGC 772.  The first shows my fields of view with the camera in its “zero-angle” position.  As you can see, there were no suitable guide stars at that point – TheSky6 tells me the magnitudes of the stars when I click on them, so I knew they weren’t bright enough.  In fact, there are only 3-4 stars in that outer annular ring that are going to work well as guide stars – hence my earlier comments about guide stars being scarce.  So I simply rotated the field of view indicator in the software (not the actual hardware) until I was positioned on some better guide stars – that’s the second screenshot.  At that point, I could compute the difference between the two position angles and know that I would need to rotate the camera assembly by about 27 degrees (146-119).  I did this manually using a little handwritten angle scale that I have fastened on the OAG assembly – it’s surprising how little accuracy is required.  I did the rotation once, tightened everything up and bingo, there were my guide stars.   Since I have a German equatorial mount, I often have to do this again when I do a meridian flip.  But with your fork mount, you won’t have that problem.  I’d recommend your doing some experimenting along these lines if you continue to have problems finding suitable guide stars. The good news is that you can work with it for awhile without having to buy more expensive gear.

 

Have fun.

Bruce

 

 

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From: mark matzner [mailto:mdma...@gmail.com]
Sent: Friday, December 05, 2014 9:30 AM
To: open-phd...@googlegroups.com
Cc: mdma...@gmail.com; bw_m...@earthlink.net
Subject: Re: Disconnect Non-responsive Camera after (seconds)

 

Hi Bruce, 

[mark matzner]

Good Stuff Bruce,

I see that TheSky6 is now available in several sizes (now called TheSkyX) from inexpensive to expensive.  Would you know at what level the guide star field of view feature is available on?  That is really a nice utility!

I will give your rotation suggestion a try tonight (weather permitting).  I hope with simple fiddling, I can find a suitable star. 

If I must rotate the OAG/Guide camera assembly 90degrees or so to find a suitable star, must I "recalibrate" PHD2?  Since I will be moving at 90 degrees to the original setup and calibration.

Mark

[bw_msgboard]

I don’t know about TheSkyX.  I have the “serious astronomer” version of TheSky6, which was the middle of three options when I got it.  I also don’t know if there are other planetarium apps that can do the same thing.  If you rotate the guide camera by a significant amount, you will need to recalibrate.  I have “cheated” and re-used a calibration when the rotation was less than 20 degrees or so.  But since the calibration doesn’t take very long, I don’t stretch things beyond that.

 

Good luck.

Bruce

 

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From: mark matzner [mailto:mdma...@gmail.com]
Sent: Saturday, December 06, 2014 12:26 PM
To: open-phd...@googlegroups.com
Cc: mdma...@gmail.com; bw_m...@earthlink.net
Subject: Re: Disconnect Non-responsive Camera after (seconds)

 

Good Stuff Bruce,