PHD v2.3.1 and ASI120MC advice and issues

droogie 2001

I have the latest USB 3 ASI 120MC camera and have purchased it mainly to perform guide camera duties.

In PHD V2.3.1 I am selecting the following settings:

Camera: Windows WDM - Style webcam camera - ASI 120MC-S Camera (ZWO Design)

Mount: Celestron Scope Driver (ASCOM)

I choose 1260 x 960 RGB 24 - Is this correct, I have also tried 640 x 480 RGB24.

Am I using the correct selection of drivers?

After a good Polar alignment and the items all talk to PHD but I am having a number of issues.

First is that the main PHD display from the camera can be quite erratic.

In that I mean the screen can change contrast quite frequently.

One moment pure grey screen the next noisy black screen. It can settle down but it does making finding guide stars difficult.

In the camera settings I am using USB Traffic: 82%, Gamme, Gain: 56, Exp: 2s

In PHD I am generally using 1.5 - 2 sec exposures. I spent hours last night trying to find the correct settings but none seemed to be perfect.

I also have the Dark library option selected.

This means that it takes an immense amount of tweaking to find a guide star. I realise that all system are different ( I am using a OAG with a focuser) but something just seems wrong.

The second issue. Once I have a guide star my guiding is not great. The graph is quite erratic in both RA & DEC. (I have included a picture of my guiding graph to demonstrate) Now I know whole books can be written on tweaking PHD but I am not sure how to go about fixing the issue and whether it is related to the point above. I have not tried PEC yet.

Lastly when I go out of PHD and back in with no changes made my screen is back to square one where I have to change all of the settings again. In that the previous settings do not yield the same display as they did before.

All in all a bit frustrating.

Can anyone help please?

Regards.

Sam@ZWO

didn't your use the ST4 port?

you can download the latest PHD from here

http://openphdguiding.org/snapshots.html

there is native ASI support called "ZWO ASI camera"

so you can connect camera though this.

about guiding camera setting

I think you can set the gain to 80 - 100

50 is too low, 1s should long enough to see a star

droogie 2001

Hi,

No I was not using the ST4 port as I was pulse guiding via the Controller Hand set.

It seems to work via the handset and pulse guiding but I guess I can try via the S4 port.

Does the ST4 cable go from the camera's port to the Auto Guider port on my Celestron AVX mount? I realise you are not technical support for my mount but the large array of options is getting me somewhat confused!?

Thanks

Sam@ZWO

yes, you can connect though ST4 directly

AVX mount is full compitable with it

droogie 2001

Ok so I tried many of the different settings last night to see what yielded the best results. One with ST4 guiding and another with the ASCOM pulse guiding.

All of this was performed with the latest PHD 2.3.1e and latest snapshot

I tried the camera: ZWO ASI Camera and Mount: On Camera

Left the Gain at 95, switched off darks, exposure 1.5 secs and set my calibration to 500ms. I know Darks are best left on but if I put them on my SNR drops down to 3-4 which results in Star lost errors. If I leave them off I get SNR 8-9. Tried gain at 70 and this worked slightly better.

Tried the ASI ASCOM Driver no great deal of difference to above.

The WDM Style Windows Web camera option and then selecting the ASI Camera was the original method of using PHD. Going back to this confirms my original problem. The screen on the PHD is a noisy mess even with darks. It’s so bad I cannot use this.

I guess my main issue is two-fold. One my view via the camera in PHD is noisy. The best SNR I can get is 10 maybe 12 but if fluctuates a lot. I hear some people are achieving 20-30 though I have no idea what cameras they are using. I realise there are numerous factors as to what effects this but does anyone else get better or similar results when using their ASI 120 MC (or MM) with PHD v2?

Included a screenshot of both my view (with no darks) and my tracking graph with ST4 guiding.

Also does anyone know of a good forum for PHD as clearly I have a lot to learn!

marcos

Hi,

I use the ASI120MC for guiding mounted on a Omympus 70/210mm zoom lens with PHD2 v2.3.1c

to guide my Meade LS6"

And I use the native ZWO ASI camera driver.

Attached a screenshot where you can see the setting that where used, hope it will help:

SCREENSHOT-900-SEC-TEST.JPG

Clear Skies

Marco

droogie 2001

Hi Marco,

Wow thanks for that. You SNR looks like it is maxed out at 29.9!

You mention that you are using an Olympus 70/120 lenses with the ASI 120MC guiding an Meade OTA.

I am having issues with trying to picture that. Would you be kind enough to post an image of your setup?

I am using an OAG with the ASI and whilst I have struggled with it I am beginning to understand the setup method. I am using an OAG as I using a long focal length (8" C8 with F6.3 FR =1280mm FL)

but I cannot see me getting close to an SNR value of 30...You also say you are using the standard drive in PHD. Is that the WDM driver or the ZWO ASI option (or something else...?)

I hope I don't have to ditch the OAG and get a guide scope system instead....I was told a OAG is essential for a long FL system...

Regards

Mike

marcos

Hi Mike,

Sorry, I forgot to mention that it is piggybacked on the scope....

Here is an image of the setup:

LS6-setup.JPG

The ASI120MC is connected with an adapter to the Olympus 70/210mm zoom lens (the diameter of the lens is 55mm f4.5 at 210mm), and fixed to the scope with a self made aluminium bracket.

I image trough an Antares FR @ 6.3 FL 900mm The FR is mounted inside the Pyxis LE derotator, that I use to derotate the starfield (The Meade LS6" is on AltAZ mount)

P6076256.JPG

I have tried as well to use the ASI with an OAG, (I got a Omegon OAG), to get more precise guiding without flexing, but to find a suitable guiding star with it is so much time consuming, that by the time I find a suitable guide star it is usually time to pack-up and go to bed....:(

And I do not have much problems with flexing...

I do NOT use the WDM driver, but the ZWO ASI camera driver, (the one at the bottom of the drivers list)

This is the image resulting of the imagining tests of which I have attached in the previous post the 900sec guiding screenshot: (I was testing how long light frames I could take without star trails with this setup)

Meade LS6" with 0.63x FR EOS1100D ISO400

Those where stacked in DSS + Flat, dark and bias

34 light frames x 240sec

5 light frames x 500sec

3 light frames x 600sec

1 light frames x 900sec

Imaged with APT and processed in StarTools.

NGC281.jpg

clear skies

Marco

marcos

Hi again Mike,

Just forgot this:

I was just checking out the first screenshot you posted.

In there I believe you were using the WDM driver.

I should try tho change the settings in the cam dialog properties (I have circled in red below):

PHD Screenshot1 (1).png

Exp = "ms" try 300-to-500

Gain = about 90

USB traffic, I should also bring it down to about 50% or less.

And then the other red circle in the exposure time in PHD2 up to 2,5 - 3 sec

By doing this PHD2 will stack about 5 to 10 frames (depending on the above settings) before issuing any commands to the mount, resulting in much more stable image and better guiding :-)

Clear skies

Marco

Sam@ZWO

MicroS is correct

you need to change the exposure time fromt the property dialog when connect though WDM driver

that's why your image is not bright enough

WDM driver is recommend to work with metaguider which use the "video" way to guider

SNR looks ugly for an OAG but it guiding better than a guider scope

so don't care too much about these parameters

droogie 2001

Hi Marco,

Thanks for the pictures. I can now see the setup layout clearly, lovely setup you have there.

Yes the first image was with initial my testing with the WDM driver.

I will try those settings but I have found the ZWO ASI one to be better as you also state that you do not use the WDM driver. However it’s worth another test what resolution do you select when you have used the WDM? 1280x960 RGB 24 or go down to 640x480 RGB24?

I guess the higher the resolution there should be more stars to choose from?

Regards

Mike

droogie 2001

Hi Sam

Thanks for your helpful tips as always.

You mentioned Metaguide and the WDM driver. I have not seen this software before I assume you mean this software?

http://www.astrogeeks.com/Bliss/MetaGuide/

May be worth a try. Nothing like making this hobby even more challenging…! :

Regards,

Mike

marcos

You welcome Mike, and thanks :-)

Yes I also find that the Zwo ASI driver is better than the WDM. Less settings to mess-up with it, and it produce better pictures.

I stopped using the WDM driver after installing PHD2 v2.3.1c that support the Zwo ASI driver natively.

With the WDM driver I was using the top of the list 640x480 setting.

Although is true that with 1280x960 you got to see more stars, with my AltAz setup, I get better results if I choose a guide star that is actually in the center of the FOV or very near to it, so a res. of 1280x960 with more stars at the outside of the FOV does not do any good to me, and actually, the smaller resolution make smaller size images to download from the cam to the laptop, and it goes a bit better. I do not know if on EQ mount you can choose a guide star in any position in the FOV with equal good guiding results, or if you also have to prefer a guide star near the center of the FOV

I also tried the 640x480 setting that is located a bit more down in the drop down list, this I believe is the binned mode, and it should yield better results, but it did not with me....

The Metaguide program also look interesting, but for the time being I will leave it alone, I want first to get full control of PHD2 before I try something else...

Hopefully we will get Clear skies this weekend to test further :-)

regards

Marco

droogie 2001

Hi Marco,

Thanks for the tips. I am meant to have clear skies tomorrow evening so hopefully I can try this out as well as a few other tweaks on the EQ mount.

Thanks again,

Mike

marcos

You welcome Mike, good luck with the clear skies for tomorrow!

Here in Belgium they have promised all the week of .......

cloudy skies and rain..

keep us posted on the progresses of your testing!

regards

Marco

lcd1080

MarcoS wrote:
Hi again Mike,

I should try tho change the settings in the cam dialog properties (I have circled in red below):

...USB traffic, I should also bring it down to about 50% or less.

Clear skies

Marco

How does one set the USB traffic, I don't have that option in my Cam Dialog Properties Parameter Setting tab. All I have in that tab is Gamma, Gain, and Exp I'm running the latest update (PHD Guidng 2.3.1g). I found that I need to keep USB Traffic below 50% in Firecapture for my 120MC to work properly there so I'd like to be able to set the USB Traffic at that level in PHD2 as well.

Thanks,

Peter

droogie 2001

I think you only get those option when you select the camera option in PHD2:

Windows WDM - Style webcam camera - ASI 120MC-S Camera (ZWO Design)

This uses a different driver so gives you more options for the camera.

I have to say it took me a while to realise that different drivers including ASCOM, ST4 & Native offer different options, it is all rather confusing!

Mike

lcd1080

Thanks Mike, after I wrote my question I tried again and was able to bring up the USB Traffic selection selector. I believe that I selected WDM to enable that choice.

The great news is that I successfully autoguided on the star Rasalhague with my ASI120MC and PHD2.3.1g (the latest software update). I used a 92mm refractor and a 2x barlow on my G-11 mount. The only problem was that a few of the RA and DEC corrections made by PHD exceeded level 4 on the Y-axis of the History graph. Can I just raise the Y-axis setting to +/- 5 to overcome this issue or do I need to make some adjustments in the settings. Here's what my results looked like last night.

Thanks,

Peter

marcos

Hi,

Not really an expert myself, but you have set the min mo at 2.45 and in dec 2.22 , I believe those values are much to high....

that could be the reason your graph is ll over the place.

Normally I use something in the 0,25 range.

the settings below are the ones that give me the best results:

SCREENSHOT-900-SEC-TEST.JPG

Regarding the driver I personally find that the PHD2 native ZWO ASI camera drive (the last one down the list of available drivers) is the one that gives best results with my ASI120MC

regards

Marco

lcd1080

Thank you very much Marco, I'm certain that you are correct, my current settings of 2.45 and 2.20 for Min mo in RA and DEC mean that my mount is attempting to correct with at least those magnitudes of stepping distance; since the maximum graph level on the Y-axis is only 4 that leads to huge swings and overshoots in both directions. It was all because I didn't know the meaning of "Min mo". Thanks for showing me the meaning of that term and the resulting error in my settings; I'll reset Min Mo to 0.25 tomorrow night when the weather improves.

Peter

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