PHD2 Anxiety

[Bluemoonjim]

Hi
I was wondering if anyone else is experiencing the same issues I have with PHD2 guiding.
I have been using PHD2 guiding for my imaging for about six months now, so still relatively new to the software. My mount is not high end, it is the Exos2 PMC8 so I know it has it's limitations. Before guiding, anything above 2 minutes was pushing the envelope as far as trailing stars. With PHD2 I can now consistently get, good quality, 5 minute subs. I have had no need, as yet, to push it further.
So, all good. Nice round stars, nice images with my 102mm f7 refractor. The stars are round, the images are pleasing... what more could you want?

I want a PHD2 display graph that looks nice and smooth rather than the saw toothed, jiggy jaggy mess that it shows me every time I'm imaging.
Maybe it's something to do with the sort of person that's drawn to astrophotography? Some sort of OCD? Maybe it's just me? BUT it drives me mad! Why can't it be nice and smooth, or at the very least, stay with in the 1" lines? Mine is all over the place and I have tried everything to improve things, including a complete strip down and re-grease of the mount, and nothing seems to improve the jiggy jaggy bloody graph!
And yet, the stars are nice and round and, for my level of equipment, the images are pretty decent.
Do I need therapy or just switch the display graph off?

[Stuart1971]

I feel your pain here too, and totally get what you mean, I can get bad graphs like yours and still get great images with round stars, and also good smooth graphs with not so good stars, it makes no sense…but at the end of the day, it’s the quality of the stats in the final image that count.

One way to smooth your graph, is to alter the scale on it, so at leat 8x or higher…this works well…👍🏼

[scotty38]

What's the resolution of your setup? if the guiding rms is below that then you're ok and I think I read somewhere guide at half the resolution is absolutely fine no issues.

With my scope and camera my resolution is 2.5"/pixel and even if my guiding goes to 2.0 rms and looks like a nurse is about to shout "clear" the stars stay round.....

8 hours ago, Stuart1971 said:

One way to smooth your graph, is to alter the scale on it, so at leat 8x or higher…this works well…👍🏼

🤣🤣🤣 I couldn't find a "head buried in the sand" emoji lol

Edited February 27, 2022 by scotty38

[Stuart1971]

48 minutes ago, scotty38 said:

What's the resolution of your setup? if the guiding rms is below that then you're ok and I think I read somewhere guide at half the resolution is absolutely fine no issues.

With my scope and camera my resolution is 2.5"/pixel and even if my guiding goes to 2.0 rms and looks like a nurse is about to shout "clear" the stars stay round.....

🤣🤣🤣 I couldn't find a "head buried in the sand" emoji lol

Yes it was meant to be funny, but not sure it came across that way….😂😂

[scotty38]

1 minute ago, Stuart1971 said:

Yes it was meant to be funny, but not sure it came across that way….😂😂

Haha, I got it 🙂

[michael8554]

11 hours ago, Bluemoonjim said:

I want a PHD2 display graph that looks nice and smooth rather than the saw toothed, jiggy jaggy mess that it shows me every time I'm imaging.

Ignoring the images that show small round stars (with diffraction spikes ???) , this could be due to many things.

What are the actual RA and Dec guide error figures ?

Are the guiding exposures too fast, causing "Chasing the Seeing" ?

Is the Minimum Move setting too high ?

Maybe you should post a PHD2 GuideLog.

Michael

 

 

[david_taurus83]

Perhaps your trying to cure a problem that isn't there? 700mm needs good guiding and your image looks great so your mount must be performing. There are ways to make the graph look flatter, you can change the scale to 4" for example. Perhaps you have it too narrow at 1"? If you also lower the X axis to 50 this will present a smoother graph.

[Stuart1971]

7 minutes ago, david_taurus83 said:

Perhaps your trying to cure a problem that isn't there? 700mm needs good guiding and your image looks great so your mount must be performing. There are ways to make the graph look flatter, you can change the scale to 4" for example. Perhaps you have it too narrow at 1"? If you also lower the X axis to 50 this will present a smoother graph.

😂😂 yes changing the graph was mentioned above….tounge in cheek….😂😂

[Same old newbie alert]

OCD or not look at the figures rather than the graph.. if the RMS is under your image scale then happy days,but if you want to look at a flat graph then change the scale .. that's what some do as most just look at the graph... Chuck likes to look at flat graphs on his tube channel

Take it you've run the guiding assistant and applied the settings? That should tell you how far your PA is out., Have you got the camera on a short loop and over compensating on the aggression?  Loads of things to look for and apply but looking at the image it don't look like there's too much wrong 

Maybe a screen shot of PhD will show more

[Shibby]

The jagged appearance could be caused by noise and/or seeing. In both cases, you can improve the situation by increasing the exposure time and enabling multi-star guiding if you're not using it already?? Other than that, I also deliberately like to keep the graph scale large 🤣

[Bluemoonjim]

Thanks for comments and suggestions. Sorry about diffraction spikes Michael, I was trying out some new Photoshop plug- ins. I'm not keen on the spikes in that image but my missus likes them, says it makes them look like 'proper stars'.🤩

[powerlord]

pfft. be glad it didn't look like this (from last night).

who knows what happened there, but as you can see it was guiding fine, and the decided to visit australia... and image startrails for the next 4 hours.

and yeh - that's some 'scale out' there... lets zoom in to the start of the 'vacation' to prove it..

It's not the first time I've had this happen for no apparent reason in asiair... everything going well, clear skies, lots of stars for tracking, and then for some reason it stopped. I dunno maybe something got stuck, but it seemed ok this morning. sigh.

 

Edited February 28, 2022 by powerlord

[scotty38]

I'm no expert but it says your settling failed and given the graph I assume you're not dithering in Dec? No idea why it never settled though and then you lost your stars it would seem.

[Bluemoonjim]

Wish I could offer something helpful. That's what I like about AP, just one problem after another. So many variables 🤪

[powerlord]

41 minutes ago, scotty38 said:

I'm no expert but it says your settling failed and given the graph I assume you're not dithering in Dec? No idea why it never settled though and then you lost your stars it would seem.

well, it lost stars because by that time it was pointing who knows where. I was dithering dec/ra. blue is ra, so for some reason it seems dec continued and ra went slow or backwards. maybe something got caught on something, that would be the obvious thing, but as I say, seemed ok in morning,.

where it said settling failed it was already 100s of degrees off. I dunno.. subs show one before perfect and clear, one after trailing mess. but remained clear all night (other mount setup was fine). As @Bluemoonjim so many things to keep just right, sometimes it goes like clockwork, other times it's like trying to juggle sand.

tbh I'm glad its now cloudy for a few nights. need a break. 😣

[scotty38]

Well I saw two dither directions but also saw DEC unaffected, well at least didn't seem to be showing the usual "unsettled" spikes but then again the RA just went off the scale rather than showing the usual up/down unsettled mess....

Do you have a cat? 🤣🤣🤣

[michael8554]

Note at point A how RA and Dec are both heading off, not due to a Dither.

Dec recovers, but RA continues eastward at what must be many times guide rate, probably at slew rate.

And that would surely result in a Lost Star situation, but there's no message.

Star Mass hasn't been enabled on the graph so I can't tell what's really happening.

At point B,  RA appears to have returned, I can't see the guide pulses so I can't tell how it's been corrected.

Only then is there a Star Lost message.

And what's the blue line at point C ?

Best to post a PHD2 GuideLog.

Michael

[powerlord]

sorry to hijack thread.

here's the phd2 log, and also asiair log which shows what it thinks it's doing.

PHD2_GuideLog_2022-02-27_183449.txtAutorun_Log_2022-02-27_183936.txt

[michael8554]

This is a puzzle.

Here's a zoomed out view of the same part of the graph I posted yesterday, with the Star Mass displayed in white.

See how the camera output doesn't change during the 400arcmin RA excursion.

 

Here's a zoomed-in view :

 

See how Dec (red) recovers, but RA (blue) disappears eastward, with PHD2 applying Max correction pulses (blue).

Point C from yesterday is now apparent in both views .

At point C, RA miraculously returns, but immediately returns to where it was, heading eastward.

I think this must be a reporting problem, as the mount and guidescope can't behave like this without loosing the guide star.

Upload the PHD2 GuideLog AND DebugLog on the PHD2 Help Forum.

Asking them to examine the section 02:57:00 onwards.

Details on how to Upload are in the PHD2 Help menu.

Make sure the date and time in the filenames are relevant.

Michael

 

Edited March 1, 2022 by michael8554