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Astrophotography and Sketching >> Beginning and Intermediate Imaging

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shawnhar
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Reged: 06/25/10

Loc: Knoxville, TN
Re: PHD - About to give up new [Re: Wmacky]
      #6172911 - 11/03/13 12:43 AM

Quote:

Quote:

Quote:

Quote:

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.cloudynights.com/item.php?item_id=2755


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Raginar
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Re: PHD - About to give up new [Re: shawnhar]
      #6173029 - 11/03/13 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.

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Wmacky
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Re: PHD - About to give up new [Re: Raginar]
      #6173034 - 11/03/13 01:59 AM

Quote:

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.


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Raginar
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Re: PHD - About to give up new [Re: Wmacky]
      #6173038 - 11/03/13 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.

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bmwbiker
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Re: PHD - About to give up new [Re: Raginar]
      #6173111 - 11/03/13 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?

Edited by bmwbiker (11/03/13 03:53 AM)


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astrodog73
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Reged: 02/22/13

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Re: PHD - About to give up new [Re: bmwbiker]
      #6173150 - 11/03/13 04:55 AM

The screen grabs definitely look like hot pixels, but the graphs suggest you are guiding on stars.... hot pixels give really nice graphs....

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Madratter
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Re: PHD - About to give up new [Re: astrodog73]
      #6173232 - 11/03/13 07:56 AM

The suggestion to try metaguide is a good one. On top of that, you should be able to focus things in daylight with that camera. Obviously the exposure will be real short.

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Wmacky
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Re: PHD - About to give up new [Re: bmwbiker]
      #6173413 - 11/03/13 10:16 AM

Quote:

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?




I did do that, and results are the pics of the graphs. I have never seen more than 2 guide stars in a frame, but usually none at all. This is with good focus on what guide stars I can find. I think I have a serious issue with the cam, or the mount, or both. I have no idea what to try next other than metaguide.

Also I'm headed out to test focus the AT6RC in daylight.

I guess next step will be another guide cam. I was thinking about a mono ASI120MM anyway as a part of my planetary arsenal, but now I'm gun shy. Do I really have to have a Lodestar?

Has anyone directly compared the ASI120MC to the ASI120MM for guiding purposes? Is there a big difference?

Thanks for the help guys, I know no astrophotography people locally, or heck, even anyone else that even owns a scope. This is my only resource.

Edited by Wmacky (11/03/13 10:19 AM)


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SergeC
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Re: PHD - About to give up new [Re: Wmacky]
      #6173546 - 11/03/13 11:22 AM

I'm not familiar with your guide cam so I can't give advice on the problems you're seeing. About your local resources, Alachua Astronomy Club is reasonably local, as is NEFAS. Both have monthly star parties and active AP-ers as members.

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zerro1
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Re: PHD - About to give up new [Re: Wmacky]
      #6173571 - 11/03/13 11:35 AM

I use a Meade DSI pro that I picked up used for $100.00 that worked so well I got a second one for another imaging setup. I have compared it to the SSAG (Orion "Star Shoot Auto Guider") The SSAG is certaily less sensitive than the Meade DSI. I always have plenty of stars to choose from with the Meade. It's not a guider in that it does not have a guide port on the camera.

do try to get guiding sorted out before you try to change mounts. a poor guiding situation would make a mount look like its in sad shape. Once the guiding is solved, it can help pinpoint problems as you learn how to regognize what is coming from the mount


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Madratter
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Re: PHD - About to give up new [Re: Wmacky]
      #6173602 - 11/03/13 11:52 AM

Quote:

Quote:

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?




I did do that, and results are the pics of the graphs. I have never seen more than 2 guide stars in a frame, but usually none at all. This is with good focus on what guide stars I can find. I think I have a serious issue with the cam, or the mount, or both. I have no idea what to try next other than metaguide.

Also I'm headed out to test focus the AT6RC in daylight.

I guess next step will be another guide cam. I was thinking about a mono ASI120MM anyway as a part of my planetary arsenal, but now I'm gun shy. Do I really have to have a Lodestar?

Has anyone directly compared the ASI120MC to the ASI120MM for guiding purposes? Is there a big difference?

Thanks for the help guys, I know no astrophotography people locally, or heck, even anyone else that even owns a scope. This is my only resource.




A couple of things:

1) If you get to the point you consider the lodestar (and I don't really think that will be necessary), also consider the SBIG ST-i mono. It is also quite sensitive and is pretty clean as these guiders go. Don't get the color one for this purpose. I have it. It works, but the mono is clearly better (it is also 100$ more which mattered to me at the time).

2) Trying to learn guiding at the focal lengths you are trying at is bound to cause frustration. Learning on a 50mm guider (which I have successfully used to guide up to 2000mm scopes) is much much easier. The reason has to do with the ease of finding guide stars. It isn't so much the focal length, as the f/ratio. The Orion 50mm guiders are f/3.2. Sure the larger scope pulls in fainter stars. But what counts for this purpose is the signal to noise ratio on the sensor. And because of that the faster the f/ratio of the scope, the more stars in practice you will have to guide with. When I realized that, it was one of the things that steered me away from the ST-80 guide scopes. The advantage of longer focal length is less difference in image scale between the main scope, and the guider. But even the 50mm does fine at 2000mm. And it is easier to secure things with less flex as well. In other words, you chose to make things hard on yourself. Maybe once you were more experienced this would have been a good idea. But certainly not now.

3) Your mount may indeed be bad. But the session last night gives no useful information on that front. Don't be so fast to conclude you need a different mount. You probably could have been using an Astro-Physics Mach1 and still had the problems you were seeing.


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CounterWeight
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Re: PHD - About to give up new [Re: Wmacky]
      #6173625 - 11/03/13 12:05 PM

I know I'm late to the party but all those first images appear to be just noise and maybe hot pixels, so there is some issue with the signal. White after dark cal shows a huge imbalance between expected and actual, so IMO all bets off until you get that completely sorted. IMO that points to the driver for the camera and the software looking with it and how. Hope the Metaguide software helps!

BTW, I can't seem to find those in the supported cameras list, is it there and I just don't see it? also don't see a direct statement that it's PHD compliant at least on the OPT site or the ZWO site. Anyway with the Orion SSAG they include PHD, at least with those I've bought - any chance there was a version on the install disk?

That you get better images unguided is great in ways as shows the mount tracking is good/decent from your polar alignment alone. I wouldn't worry about the mount based on what is happening here with this guide camera issue.


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Dwight J
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Re: PHD - About to give up [Re: CounterWeight]
      #6173668 - 11/03/13 12:30 PM

As mentioned already, using a 6" F9 scope, even with a reducer, is way too long a focal length to guide with initially. The field of view, especially with tiny chipped guide cameras, is very small making it highly unlikely a suitable guide star will appear. You will need to inset an eyepiece and use the screws in the guidesscope rings to center a suitably bright star, then reinsert the camera and focus it. Use of a par focal ring will simplify this operation in the future.

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Wmacky
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Reged: 11/24/07

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Re: PHD - About to give up new [Re: Dwight J]
      #6174266 - 11/03/13 06:45 PM

Thanks for those comments.

As to guiding with the AT6RC. Yes, I know it's not the best way to begin, but with reports of people finding lots of guide stars with the newer sensitive cameras, even with OAGs on SCTs, gave me hope. Perhaps, this isn't as true as I had read?


I had never used the AT6RC before so today I test focused it in daylight, and it focused ok. With the ASI the view was kinda soft, and washed out. Not a very impressive view. Same with it in the EON 80, but no real problems found. However, as others have stated, the FOV (even with a FC) was indeed tiny. Focusing on my neighbors fence about 200' away showed a single nail head surrounded by a small amount of wood! I'm starting to think that those who reported plentiful stars with this MC version cam were using a Mini guider.

What next?

Well, I guess I could wait, and try Metaguide next weekend if it'd clear. (weekends only for me).

Or I could purchase a better mono cam, or a 50mm Mini guider, or perhaps both?

I can't really think of anything else to try. I feel that waiting and just trying to adjust PHD setting numbers will waste out another good weekend.

I'd still love to hear from someone that has atempted to guide with the ASI120MC at a longer FL. (> 1000mm)

Edited by Wmacky (11/03/13 07:35 PM)


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Raginar
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Re: PHD - About to give up new [Re: Wmacky]
      #6174288 - 11/03/13 06:56 PM

Seems a little excessive. You didn't even try meta guide. A finder guider would probably be a better bet than using your RC though.

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Wmacky
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Re: PHD - About to give up new [Re: Raginar]
      #6174320 - 11/03/13 07:18 PM

Quote:

Seems a little excessive. You didn't even try meta guide. A finder guider would probably be a better bet than using your RC though.




Probably right. It's just in Florida we are afforded a small imaging season of just a few precious dry months. I sure hate to waste the good cloud free ones!


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frozen.kryo
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Reged: 01/28/11

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Re: PHD - About to give up new [Re: Wmacky]
      #6174476 - 11/03/13 08:57 PM

Have you tried using the ascom chooser to select the guide camera? (instead of using wdm?)

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Raginar
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Re: PHD - About to give up new [Re: Wmacky]
      #6174583 - 11/03/13 10:06 PM

Well, if your budget allows, get the lodestar/mini-guider. You won't be disappointed. It was the best purchase I made when I upgraded from a SSAG.

The lodestar is such a beast!


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astrodog73
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Reged: 02/22/13

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Re: PHD - About to give up new [Re: Raginar]
      #6174836 - 11/04/13 03:53 AM

+1 for lodestar... I guide with one, I'm tossing up getting another to image with... A friend guided on a galactic core once with his lodestar.

I would also pick up a cheap, fast, short achromat, and use that instead of the RC.... I've never heard of anyone using an RC as a guide scope (might be a reason behind that??)


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Wmacky
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Reged: 11/24/07

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Re: PHD - About to give up new [Re: astrodog73]
      #6175026 - 11/04/13 09:01 AM

Good news first - I was able to order an adapter for one of my 50mm finders, So I'll have a new guide scope for $29.


Tha bad. Wow, the lodestar is more expensive than remebered! Thats a big expense with IDAS filters still to purchase, a light box supplies needed. Any less expensive options for a sensitive cam? I was thinking about purchasing a ASI120MM for plantetary work anyway, but there's not much info on these being used for guiding, and it's bad to be a trail blazer when a newbie! Especially, after using the MC version with no real guidance available from other users with that cam.

Edited by Wmacky (11/04/13 09:14 AM)


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