ASI220MM mini and camera drivers

bulrichl

Can I still hope for an answer from ZWO?

Bernd

Skolgi

i Think i have a Problem that fits in the same direction with you.
I USe the 220mm mini with ASiair for guiding. And when i activate looping the 220mm i get a milky white background even if the cap is on the scope. Thats in different kinds until i set "High Gain 350" and 1 sec exposure - Here is the background dark as it should be.
If i set the220mmas a main camera - it work as should.
Activate / re-create Dark Lib ect did not help.
My opinionis that there is a issue with the cam so the automatic stretch sets on a wrong point!

After all the cam is working. On Day i can focus on far away trees but its hard as the cam is realy sensitive.... and in the night i have guiding stars, but its hard to see as there is no contrast between the stars and the background.
Ticket is open and wait for feedback.

Greetings

Kai

bulrichl

Skolgi On Day i can focus on far away trees but its hard as the cam is realy sensitive.... and in the night i have guiding stars, but its hard to see as there is no contrast between the stars and the background.

Thank you for posting your experience with this camera. In my view, the fixed offset value of 200 is causing the low contrast that we both observe.

As of now I am using the ASI220MM mini with an exposure time of 2 s and a gain value of 192 (i.e. in PHD: 32 %). The effective offset value is 200, no matter which offset value was set in the driver, -> item 1 in post #8. With this setting, guiding is possible with my guide scope (aperture = 60 mm, focal length = 355 mm), but it is not ideal because of the high offset value that cannot be changed. This clearly is an issue of the camera driver.

I am using the direct camera driver v3.24 for the guiding camera, the ASCOM camera driver v6.5.26 for the main camera, and PHD2 v2.6.13 dev5.

I would like to get an answer from ZWO: Why is the offset value immutible?
Please update the camera driver in order to allow setting different offset values.

Bernd

Skolgi

In Asiair i have no option to change things - just the Gain and exposure time.
At least i want to be on a 1 sec exposure as my harmonic drive need faster ewxposure for better outguiding the graphs - thats why i updatet from a 120mm to a 220mm.

Kevin_A

The 220mm mini is the worst contrast camera I have ever used for guiding. I have been asking ZWO for awhile why this camera image is so milky white instead of dark like all my other guide cameras. Darks have no effect either. Is it an offset issue or just because it is not a quality Sony sensor. I only use it in Asiair and not in phd2 but do notice a bit of an improvement when used as an imaging camera in asiair but not when used as a guide camera.

ZWO, can you please take a look at this and see why the ASI220mm mini camera image is so greyed out and lacking contrast. Thanks

Tech@ZWO

Kevin_A What is the version of ASIAIR APP and firmware? i remember we have optimized something on guide earlier, please try the newest. thanks.

Kevin_A

Tech@ZWO I am using the latest beta Testflight. It has been washed out and grey ever since I purchased the 220mm mini and I have updated my Asiair Plus at every firmware update. I use 120, 290, 220mm minis and even a 678mm and they are all dark and black and the only one that has no contrast and is very grey is the 220mm mini. It is like the offset for this camera is very high.

bulrichl

Kevin_A It is like the offset for this camera is very high.

Yes. In post #8 of this thread I gave a detailed description of the issue. Summary:
The offset value is not settable in the camera driver. The default value is way to high.

There are two other issues:
The sampling is only 11 bit for gain values > 99.
The documentation says: that the switch from LCG to HCG occurs at gain = 106, but in fact the switching point is gain = 107.

Bernd

Skolgi

I used the 220mm mini for testing with asistudio, as the zwo support ordert me to do that. So the problem is the same bit not in a factor that sould be a problem.... so as i just was connectet to my Laptop i install phd2 and the cam work good. With 68 gain and 0.5 / 1.0 sec .... fine contrast.
Again today on my Asiair i have the "old problem" but with same settings connectef as main camera i get good contrast as i should.
"M" GAIN 68 and 0.5 or 1.0 sec.
So i think the Problem is not the driver as it work with phd2 and asistudio. Maybe the V2.3 version of Asiair have a problem in the Guiding Section.

Still connected via Email with ZWO Support.

Greetings Kai

Skolgi

Here are 2 screenshots. Same settings: Gain 68. 1 sec exposure. One in the Guiding section, one as main camera in "preview"

Greetings Kai

Gatsu87

Skolgi have you resolved the problem? I just bought asi 220 mini and i have same problem in guide screen in asiair. It's been 5 months and zwo forgot to fix the issue with updates.

Tech@ZWO

Gatsu87 The histogram stretch on the guiding interface is fixed and doesn’t adjust automatically based on the image. As a result, the image may appear low-contrast if the fixed stretch isn’t suitable. However, this does not affect guiding performance — it’s only a visual difference. We’ll also look into possible ways to optimize this in the future.

Gatsu87

Tech@ZWO I understand that it is only a visual difference but you can't even distinguish the stars because there is no contrast between stars and background. Since it is a known problem since January it would be nice to be able to solve it after 5 months. There is a post in your official Zwo profile on Facebook where Zwo says that it will be solved in the next version of Asiair, is it true? I attach a screen of the post and your answer.

Thanks for the support

Tech@ZWO

Gatsu87 For sure we will continue to optimize this in the future. please look forward to the next version. thank you.