ASCOM driver v1.0.3.18: Bad bias stability

bulrichl

I use a ZWO ASI294MC Pro since January 2018. When I got this camera I installed the (at that time) current drivers (native: v3.0.0.2, ASCOM v1.0.3.12). I am capturing with SGP, using the ASCOM driver.

Eventually I measured gain, readout noise and dark current for my camera. Then I read the thread on CN, https://www.cloudynights.com/topic/628854-zwo-asi-1600-mc-pro-discontinued/ , #12 and #15, where Sam recommended to use the latest ASCOM driver in order to benefit from improvements that result in a lower dark current.

So on 11th of August 2018 I updated drivers to native v3.0.0.4 and ASCOM v1.0.3.18 and repeated the measurement. I got the same gain, readout noise and dark current values as before. However, I experinced that the bias stability (= reproducibility of the bias in separate capture sessions), that was good with the old driver, was very bad now. My conclusion is that there must be a severe bug in the ASCOM driver v1.0.3.18.

Today I realized that again new drivers (native: 3.0.0.5, ASCOM: 1.0.3.21) have been released at 17th of August 2018. Unfortunately, the change log files don't provide detailed information about the changes:

Native driver

v3.0.0.5 2018.08.17


-------------------------------------
- add new cameras

v3.0.0.4  2018.05.04
-------------------------------------
- add 120MM-Mini

v3.0.0.3  2018.01.22
-------------------------------------
- add 1600GT

v3.0.0.2  2017.10.12
-------------------------------------
- add 294MC

- fix driver date

ASCOM driver

v1.0.3.21


-------------------------------------
- Update SDK to V1.13.0821
- Fix some bugs

v1.0.3.18
-------------------------------------
- Add "Advance" option to "Setup" Dialog

v1.0.3.15
-------------------------------------
- UI of pre-defined setting changes

v1.0.3.12
-------------------------------------
- Add unity gain mark to gain label

- Add support of R/W camera ID

Also there was no thread about the new versions in the "SDK & driver" board.

I would like to know:

1) Is the bad bias stability with ASCOM v1.0.3.18 a known issue?

2) Has the bias stability been restored again?

3) Which bugs have been fixed in the ASCOM driver 1.0.3.21?

4) Is the update to SDK 1.13.0821 important for the usage of an ASI294MC Pro?

Please reply to my questions. I will have to decide soon whether to revert to the ASCOM driver v1.0.3.12 or update to v1.0.3.21.

Bernd

chad

Hi Bernd,

Got your message.

For Bias stability, I checked the code from V3.0.0.2(2017/10/12) to V3.0.0.4(2017/5/4), during this time, we changed the code to solve the problems of long exposure. These code should not affect the bias field. So I need more information about this problem.

For the fixed bugs. we tried, but failed. The reason is that it is difficult to describe each problem in detail (in that case, the release note will become uncontrollable), and as a result, many users mistakenly think that their phenomenon has been solved, but it may be a different problem, which leads to a lot of unnecessary misunderstandings. Therefore, it is difficult to meet all the requirements.

For your 294, you can have a try. There are some improvements, but I'm not sure if they work in your use.

Thanks

Chad

bulrichl

Hi Chad,

chad wrote:

For Bias stability, I checked the code from V3.0.0.2(2017/10/12) to V3.0.0.4(2017/5/4), during this time, we changed the code to solve the problems of long exposure. These code should not affect the bias field. So I need more information about this problem.

For the fixed bugs. we tried, but failed. The reason is that it is difficult to describe each problem in detail (in that case, the release note will become uncontrollable), and as a result, many users mistakenly think that their phenomenon has been solved, but it may be a different problem, which leads to a lot of unnecessary misunderstandings. Therefore, it is difficult to meet all the requirements.

Yes, I understand this very well and will contact you per PM. I will explain in detail what I found.

Bernd