Gain and Offset changing during sequence

I’m running version 2.1.7a, executing a sequence started from the on the fly tab.

I have a one line sequence with gain set to 200 and offset set to 50 (using ZWO Native driver). I noticed that some of my subs had a lower ADU than expected. When I looked at the FITS header I saw that the first sub captured had the correct gain but subsequence subs had a gain of 75. When I aborted the sequence and restarted it, the first sub had the right gain but the rest again had the gain set back to 75.

This is also seen in the filenames:
First file: sh2-157_LIGHT_Ha_180s_BIN1_-10C_001_20190812_004806_721_GA_200_OF_50_W
Second file: sh2-157_LIGHT_Ha_180s_BIN1_-10C_002_20190812_005137_401_W

Is there a setting somewhere that is causing this?

Is there any data I can provide to help figure this out?

Thank you,

Here is a screenshot of the sequence.

Screen Shot 2019-08-12 at 12.20.21 AM.png

There is not setting can do this, if you choose native voyager drive gain and offset must work. Please send to support mail the sequence file and the log files.

All the best

I sent the files. Thank you for the fast response.


Leo responded to me via email very quickly. Great support!

This issue only affects Cyclic Round sequences. It does not affect Group By Slot. And it only happens when the gain and offset in the sequence differ from the gain and offset in the setup tab.

This is a minor issue for me as I can use Group By Slot. I captured some frames last night successfully.


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Hello Nathan,

i’m in a short holiday with my family … i solved the bug but i’m finishing to add the colorblind management that a user asked to me … i’m in the middle i cant pubblish without finish this special things. I hope to finish this night.

The release will be a daily build … so you can test for me if all is ok … i dont have an ASI camera with me.

All the best and thanks

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I tested the new build 2.1.7c with an ASI1600.

I can confirm that the gain and offset specified in the sequence are used to take images for both “Cyclic Round” and “Group by slot” for all images and that the value are different from the preset. I checked the gain and offset in the filename and FIT header. I also verified that the image used the specified gain by checking the median value of each image.

In short - it works.

Thank you for the fast fix. Enjoy your holiday.


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Thank you so much for feedback