SSAG and PHD2 - total guiding fail, help!

[jschusterman]

Hey all, after a massive guiding failure last night, I thought it was time to reach out! Last night was only the 2nd time I tried to guide with the new SSAG. The first time a few weeks back, I got the SSAG and PHD2 to "work" but the guiding was just ridiculously off. However, last night made me think something might be wrong. So... I realized that my SSAG has either a ton (dozens) of hot pixels or bad pixels, and nothing I did could get it to actually see any real stars, but those dozens of white dots remain whether the guide scope camera cap was on or  off (see pic below, those aren't stars!). I actually had to detach the SSAG and just point it up at the moon to make sure the sensor was getting any light at all! It was!

 

So, I tried all the fixes I've read on this and other forums, with no success. Even tried a bad pixel map calculation, which failed (also see pic). And I tried using dark library, which only created intense noise in the frame. PHD2 would allow me to select "begin looping" as well as "begin guiding", but I would get no RA or DEC lines on the graph, and all 0.00 on the history window (also see pic). PHD2 acknowledged that the camera and mount were connected, but "CAL" never turned from red to green.

 

So I'm at a loss at the moment. Any chance this is faulty equipment? Normally I assume it's just me. Any help would be greatly appreciated!

 

- Josh

 

P.S. I finally nailed my polar alignment last night! So I don't think that was the source of my problems.

AVX mount, Celestron C8N, 50mm guide scope

[newbie alert]

I'm on a Avx too..and also having problems are you using Ascom platform? I'm not too sure what's going on with mine as it was guiding but now it seems like I'm on the simulator..think I've either installed the wrong driver or I have a bug..

Or just plain stupid...

One of those,I have an idea which one..

[paul mc c]

I too am at a loss,i also keep getting the message as in your second pic..........im very close to packing AP in, it is that frustrating.

I am using an NEQ6 Pro and qhy5.

[geordie85]

Have you tried increasing the calibration steps? I have mine set to around 2500.

I'm at work at the moment so can't screenshot.  Unless someone else chimes in I'll give a more detailed explanation when I get home. 

[Davey-T]

Star not moving enough or not at all indicates a trying to calibrate on a hot pixel.

If you slew the scope a small amount the spots that move are stars, use one of those and loop at around 2 sec's,  to get enough movement on the calibration alter the step size right up or right down can't remember which then it should calibrate in less than ten steps and you can refine it to about a dozen steps.

Dave

[newbie alert]

I'm using the auto star select thing and still getting that

[Davey-T]

10 minutes ago, newbie alert said:

I'm using the auto star select thing and still getting that

It will auto select a hot pixel, best to choose your own, what FOV is your guide scope and where in the sky are you looking ? some parts of the sky have surprisingly few stars.

If you defocus a bit the stars will get bigger and the hot pixels stay small, are you sure you're focused properly ?

Dave

[newbie alert]

I'm using a 9x50 finder guider..

So you advise to slew the mount and choose a star that moves

[Davey-T]

8 minutes ago, newbie alert said:

I'm using a 9x50 finder guider..

So you advise to slew the mount and choose a star that moves

Yes not a lot then you should see the " real " stars jump as it loops, the hot  pixels won't jump, are you sure you've actually got some stars focused  and not just hot pixels ?

It's worth focusing on a really bright star first so you can be sure it's focused on the stars.

Dave

[newbie alert]

Ok ,Thanks.. .I try next clear night!!

I have had very low snr on stars  (5.5-7) but last time I had one in the 20's.. still didn't calibrate thou

[Davey-T]

SNR numbers can be very misleading, I tend to ignore them.

Dave

[newbie alert]

22 minutes ago, Davey-T said:

SNR numbers can be very misleading, I tend to ignore them.

Dave

You can't ignore it if the star gets lost 

[kens]

Screen shots are no use for analysis. Please attach the guide log from that session. Either by saving in Dropbox or equivalent an provide the link; or zip it up and attach the zip file.

One thing I can see is tht you have the screen gamma slider over to the far right which makes the display dark. Move it to the left till you can see stars.

 

[geordie85]

Ok I'm home now. To check your calibration is high enough you'll need to click the brain highlighted in green. Then you'll need to click guiding. You need to change your calibration step high enough to make your mount move.

Also, as mentioned above, you need to move your slider further to the left. It's the thing in between your exposure setting and the brain.

[Davey-T]

1 hour ago, newbie alert said:

You can't ignore it if the star gets lost 

It gets lost if it's too bright as well as too dim so best to do it by eye.

Dave

[jschusterman]

Thanks for chiming in everyone! I actually did try slewing, but there were literally 0 stars showing up, even at longer looping exposures. Everything you see in this picture is NOT a star, and I know because it was exactly the same after slewing, with guide scope cap on or off, slewing to different parts of the sky, etc. And moving the gamma slide even just to the middle caused a screen of total noise, which is why I eventually left it all the way to the right.

So I guess my issue is that my SSAG isn't "seeing" any actual stars at all. Only bad pixels or hot pixels. Has anyone here so far ever had that issue of just tons of bad/hot pixels right from the start?

Oh, and I tried adding short, medium, and long tube extensions just in case it was a focus issue, but I still never saw anything other than those same white pixels. :-/

In regards to kens request for guide log, there is none because it never actually guided (even though it did "allow" me to click the "start guiding" button). I just checked again, and there's no option in the PHD2 menu anywhere to pull up a guide log.

 

- Josh

[glowingturnip]

sounds like focus to me...

as you know, you've got a lot of hot pixels there and your calibration is failing 'star did not move enough' since you tried guiding on one (been there, done that).  Using the dark frames does help a lot because it removes them, but as you say with no real stars showing, when you use the dark frames the noise explodes - that's because  PHD auto-stretches the screen to show what's there, and with nothing there all you'll see is noise, but as soon as you see a real star, with darks applied, that noise will all fall away to nothing, so do use darks.

The focus on the guiding set-up can be surprisingly demanding, even just slightly off and you see nothing at all, and only start to see the star when close to true focus.

Try setting up in daytime, aim at a distant object, and then get the guidecam into focus on that (probably can't do that with PHD, use something like EZPlanetary or Sharpcap or whatever).  Once you have focus, mark the position so you have an idea where focus will be at night.  

If you're lucky, maybe you can get the guidecam to be parfocal with an eyepiece then it's easy to focus at night - my QHY came with a parfocal ring, not sure if your SSAG does ?  If so, focus with your chosen eyepiece in, then without changing focus on the scope, put the camera in instead and manually slide it in or out of the tube until you find focus with it too - once there, set the parfocal ring to give you that distance.

[newbie alert]

Your guide log is in the documents file usually...

When you load up phd it will tell you where the guide log is

[jschusterman]

For kens and anyone else who understands these logs, here are my logs from the other night!

Gonna try to work on focus during the day sometime this week. Could get a little tricky because my 50mm guide scope is a finder scope. If inward focus in the issue, pretty much nothing I can do, but if it's outward focus, I can just keep adding tube extensions.

Huge thanks for letting me know the situation with the gamma bar and noise!

PHD2 logs.zip

[paul mc c]

1 hour ago, jschusterman said:

my 50mm guide scope is a finder scope.

Does your finder front lens not adjust...

[IanL]

On 05/09/2017 at 19:50, paul mc c said:

I too am at a loss,i also keep getting the message as in your second pic..........im very close to packing AP in, it is that frustrating.

I am using an NEQ6 Pro and qhy5.

Assuming this is the original QHY5 go in to the camera driver settings and increase the gain to 95% before you press the connect button. (You can't adjust the gain with this driver after PHD has connected). If you don't you will likely just get hot pixels and no stars.

More generally for both of you, use a standard capture application (Sharpcap, FireCapture or whatever). Work with something bright like the Moon to find the focus point with your camera and guide scope as it is much easier than with stars. Lack of back focus is a common problem with ST80 and finder guider setups so you may need an extension tube if so.

Once you know where focus is, measure it with a ruler from an identifiable point on the scope to an identifiable point on the camera to find it again quickly on future.

Next work with the capture application and a bright star to find an exposure time and gain settings that will show it clearly. Then try for fainter stars.

Use the gain and exposure settings in PHD and you should have more luck now. Exposures of 4 seconds are fine, you shouldn't need anything less in most cases as too frequent guiding on short exposures will chase the seeing and cause more problems than it solves.

Don't defocus at all, only usually helpful if you can't avoid saturation of guide stars by reducing gain.

Bear in mind that the on screen gamma slider has no effect on guiding and it can fool you in to thinking you have good stars when you don't.

[Davey-T]

To check if your camera is actually working shine a torch in the front of the guide scope while looping and the screen should turn white, if it does then it's probably just not focused.

Dave

[kens]

Another thing you could try is to simply see if you can see an image in daylight in PHD2. If you can then use the manual guiding option (Tools > Manual Guide), set the Guide Pulse Duration to 5000 (that is 5000ms or 5 seconds). Then press each of the N/S/E/W buttons in turn. Each one should cause the scope to move a small distance for 5 seconds.

[jschusterman]

54 minutes ago, paul mc c said:

Does your finder front lens not adjust...

As far as I can tell, is does not. Seems to be completely fixed.

[newbie alert]

Well I can report back that my stars are indeed all noise..so I can't calibrate as they're all hot pixels Inc using a bad pixel map..i tried to readjust the focus and it didn't change nothing,putting my hand over the front had the same effect..strange thing is when put the cap on to re do the darks for the bad pixel map the" star was lost " So had high hopes for calibration but no...moving the mount didn't make anything move on the screen..So the big question is should I change my camera( Skyris 236m) or the finder/guider..which is a converted  skywatcher finder?  Or both?