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PHD - About to give up

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#1 Wmacky

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Posted 02 November 2013 - 09:01 PM

Well here I sit in the observatory after 4 hours of frustration, and not 1 image to show for it. I can't believe it's really that hard to even see stars. I have everything else working so well,including Astrotortilla, BYEEOS, and Stellarium. I can locate, slew to, center, and image anything I want, but I just can't guide.

The issues -

Unintuitive, unexpected, and bizarre results, from making small setting changes.

No guide stars showing up except for very bright stars.

If gain is turned up I get thousands of pin point dots?bNoise? Hot pixels?

If I turn the gain lower I get a black screen with no stars.


If I take a dark frame, and then start the loop, I get a pure white non changing screen. Deletig the dark frame turns the screen darker again.

I did try guiding on some of the brighter stars that weren't near my target just to see if it would guide. I got wildly oscillating graph lines, and the lines woukld eventually leave the graph all together.

It really can't be this hard right? If some screen captures would help I'm take some before I roll the roof shut, and call it a wasted night.

#2 shawnhar

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Posted 02 November 2013 - 09:07 PM

Unintuitive, unexpected, and bizarre results, from making small setting changes.

What settings were changed?

#3 Raginar

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Posted 02 November 2013 - 09:12 PM

We need to know what you're guiding, how you're guiding, and your settings to help.

And, PHD is the easiest of the guide programs.

#4 bmwbiker

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Posted 02 November 2013 - 09:28 PM

Maybe you have covered this but I have to ask..
Sure you are in focus?
Does covering up the guide scope objective make your "stars" disappear?
Have to tried forcing a fresh calibration?

#5 zerro1

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Posted 02 November 2013 - 09:34 PM

What guide camera are you using?

#6 Wmacky

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Posted 02 November 2013 - 09:35 PM

Guiding through a AT6RC with a ASI120MC
Picking WDM Webcam from list
Focused on a bright star.
Used to see a greyish background with some bands like in examples, but now just see a black screen with bright tiny pixels that are not stars. will ulpoard screen shots next.

#7 Wmacky

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Posted 02 November 2013 - 09:43 PM

Low gain setting at 6


Posted Image




Gain at 20

Posted Image


Gain at 50ish


Posted Image







Looping after taking a dark frame. *BLEEP*?


Posted Image

#8 bmwbiker

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Posted 02 November 2013 - 09:45 PM

Do you have the extenders on the AT6RC?
I need the 2" extender plus another extra 1" in the camera coupling to get my DSLR into focus.

If your still stuck you might try simply try to get a focused image in PHD during daylight hours. Even a small amount of out of focus will cause ALL the stars to just be dispersed into the background.

#9 Wmacky

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Posted 02 November 2013 - 09:47 PM

using the correct spacers - bright stars in focus.

#10 Wmacky

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Posted 02 November 2013 - 09:48 PM

Unintuitive, unexpected, and bizarre results, from making small setting changes.

What settings were changed?


Gain, Gamma, exposure, dark frame

#11 zerro1

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Posted 02 November 2013 - 09:53 PM

I gotta ask just to cover the bases so don't take it the wrong way. You did cover the scope when you took the dark right?

#12 bmwbiker

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Posted 02 November 2013 - 09:56 PM

using the correct spacers - bright stars in focus.


I don't see any "bright stars" in your screen captures, just pixel noise. In focus using what? (an eyepiece?). There is no guarantee the the camera is parafocal with anything else, in fact it is likely NOT to be parafocal with other observing equipment.

PS: 2.5s is long (IMO) if you go down to say 1s you can boost the gain without getting so much noise. But its not clear to me that your camera is "in focus".

#13 Wmacky

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Posted 02 November 2013 - 10:44 PM

I was "at least originally" in focus on a bright star. However it did seem to need touching up just now, and that helped a very little. You don't seem any bright stars in any of my captures because frankly there doesn't seem to be many in the sky that will even show up.

For example right now I have it guiding while imaging the Pleiades. But had to decenter it just to find 1 star to guide on, and even that one is beeping at me here that there.

Maybe this cam is just too weak, but there have been reports that it is sensitive, and others are using it with success?

#14 Wmacky

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Posted 02 November 2013 - 10:46 PM

I gotta ask just to cover the bases so don't take it the wrong way. You did cover the scope when you took the dark right?


I did

#15 shawnhar

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Posted 02 November 2013 - 10:54 PM

Unintuitive, unexpected, and bizarre results, from making small setting changes.

What settings were changed?


Gain, Gamma, exposure, dark frame

Used to see a greyish background with some bands like in examples, but now just see a black screen with bright tiny pixels
So it was working, then gamma and exposure were changed and now you get a black screen?

#16 Wmacky

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Posted 02 November 2013 - 11:05 PM

To top it off, I think this $2000 mount may be junk. It can't seem to keep up, and PHD ends up losing the star!




Posted Image



Posted Image

#17 Wmacky

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Posted 02 November 2013 - 11:10 PM

Unintuitive, unexpected, and bizarre results, from making small setting changes.

What settings were changed?



Gain, Gamma, exposure, dark frame

Used to see a greyish background with some bands like in examples, but now just see a black screen with bright tiny pixels
So it was working, then gamma and exposure were changed and now you get a black screen?



Well, not exactly. It never did really work right, but seemed to get even worse yes.

Here's what i have learned in the last hour. If there are no real stars displayed, you get the jet black background, with bright tiny pixels. Again, if there are no stars displayed you get a bright whiteS screen after doing the dark frame.

So the real issue is no stars, or very very few. Well, that, and the fact I think I need another expensive mount!~



#18 Madratter

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Posted 02 November 2013 - 11:13 PM

What are you using as your guidescope? Nevermind, I see it is the AT6RC.

Your settings are way off. For example, your minimum motion is way to small given you are using the AT6RC.

#19 Wmacky

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Posted 02 November 2013 - 11:20 PM

do you have a starting point for the settings?

BTW, tonight I was using a .5x focal reducer on the AT6RC to help with finding guide stars. Didn't really help, but the scope was guiding at 1/2 it's normal FL. As you can see, the stock setting still didn't work even in this case.(guiding at FL685mm)

#20 Madratter

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Posted 02 November 2013 - 11:24 PM

Well, I don't have direct experience with trying to guide at that long a focal length. But I can tell you that minimum motion probably needs to be up around .5 if not more. I can also tell you than you will need to up the size of the box in PHD that it surrounds the guidestar with from 16 to 50 (which is the maximum). Set your RA aggressiveness down to around 80. Set your hysteresis to around 25.

#21 shawnhar

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Posted 02 November 2013 - 11:43 PM

Unintuitive, unexpected, and bizarre results, from making small setting changes.

What settings were changed?



Gain, Gamma, exposure, dark frame

Used to see a greyish background with some bands like in examples, but now just see a black screen with bright tiny pixels
So it was working, then gamma and exposure were changed and now you get a black screen?



Well, not exactly. It never did really work right, but seemed to get even worse yes.

Here's what i have learned in the last hour. If there are no real stars displayed, you get the jet black background, with bright tiny pixels. Again, if there are no stars displayed you get a bright whiteS screen after doing the dark frame.

So the real issue is no stars, or very very few. Well, that, and the fact I think I need another expensive mount!~

I think you should go to a bright star and use the cam dialog to adjust gamma/gain/brightness, etc... until you can see the star clearly in the PHD screen, you may need to decrease the slider in PHD that adjusts the brightness, it's just for you though, has no effect on guiding. I had similar issues using a webcam where I had the gamma/gain settings messed up, it would either be super bright or super dark and really picky about the settings.
Then read this:
http://www.cloudynig...hp?item_id=2755

#22 Raginar

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Posted 03 November 2013 - 01:52 AM

Use meta guide. It's designed for the type of guide camera you have. PHD doesn't work well with direct draw cameras.

#23 Wmacky

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Posted 03 November 2013 - 01:59 AM

Use meta guide. It's designed for the type of guide camera you have. PHD doesn't work well with direct draw cameras.


I'll look into Metaguide.

I spent another couple hours with not much luck. I did notice that my images looked better using no guiding at all! I tried change the settings to no avail. PHD just can't control the dec. It will for a bit then go off scale. I read the post of Stelios for the other day as he had the same issue and was able to cure it by turning of guide commands, and watching for N or S commands from PHD. then set the setup to guide that direction. I did this and found N commands being sent. I set it to North, but it still went off scale. Hope seems bleak! I'm going to bed for a bad night sleep. :p

#24 Raginar

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Posted 03 November 2013 - 02:02 AM

Tea, those are warm pixels I'm pretty sure. Dude, I haven't tried a direct draw camera with PHD but I've read about some horror stories. Meta guide was written specifically with them in mind so it should be easier to control.

#25 bmwbiker

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Posted 03 November 2013 - 03:51 AM

Its hard to perform diagnosis from a distance, but I'm just don't see a image of stars in your screen captures. Suggest you slew the scope to a very bright star and make sure you can see and focus on it with the guidecam and PHD. So there is no ambiguity about framing, focus and exposure.

If you got is setup right it will be a question of which star to chose as a guide star. Not is there a guide star?






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