RBI pre-flash does not turn off on SBIG 16803

Sequence Generator Equipment Compatibility
1

I have an SBIG 16803, C14 Edge HD & Paramount MX+. Up until recently, I have done my imaging with The SkyX Camera Add-on. Outside of some star elongation issues which I worked through I did not experience any particular problems.
I bought Sequence Generator Pro with a view to utilising its superior sequencing abilities. I set up the camera and entered some values into the RBI pre-flash exposure and number of flush boxes, frankly not really knowing what it was for. I subsequently got the arcs in my images, which I presumed was some sort of reflection. Unfortunately I had done some maintenance and cleaning work on my OTA coincident with this and presumed I had done something to introduce a reflection. I went back to The SkyX and was still getting these arcs, which made me think the issue lay with the OTA. However a 90 degree rotation of the camera saw the pattern maintain its orientation, proving the issue was with the camera. After some consultation this was diagnosed as the classic RBI pattern, with curving arcs. OK, so now I understand what RBI is all about and it was being generated by an IR pre-flash.
I was advised that unless I had very bright objects in my images, the ghost images that result from RBI would not be a problem and that I should run without it. I set he number of flushes to zero which is supposed to turn the RBI pre-flash off. But after I did this I was still getting the pattern and even when I went across to image with The SkyX Camera Add-on.
After some discussion with Diffraction Limited, noting that I couldn’t get CCDOps working, they suggested I download Maxim DL, which I did….well the 30 day trial anyway. It has an option to capture “Raw” and another for “Raw + pre-flash”. I selected the former and produced darks without the pattern. I then turned the pre-flash on with the default of a 4 sec flash and 3 flushes. This produced the pattern. I then went back to “Raw” and took a series of images over a half an hour watching the pattern fade away.

I then went to The SkyX and took a dark with no pattern.

Next over to SGPRo and again, having selected 0 flushes (i.e. no RBI), I took a dark, with no pattern. I then turned on the pre-flash and got the pattern as expected. I then set the number of flushes to 0 again and this is, as I understand it, supposed to effectively turn pre-flash off. However, as I took images over the next 3/4s of an hour they did not fade, indicating the pre-flash was still being applied.

I then went waited a half hour before going back again to Maxim DL, set it to “Raw” i.e. no pre-flash and took a dark. No pattern. I then turned pre-flash back on to give the pattern.

I then went back to The SkyX and after waiting half an hour I took another dark. The pattern would have faded away in this time, but no, it was there bold as brass.

So in summary, once I turned on the pre-flash in SGPro, it simply stayed on despite my having set the number of flushes to zero, which is supposed to turn it off. The SkyX Camera Add-on, has no RBI pre-flash input and so it seems that when it is used the last RBI pre-flash setting is applied. It wasn’t until I download Maxim DL and set the option on Raw that the pre-flash was finally turned off.

Can you advise whether there is another way that I haven’t understood to turn the pre-flash off, if so the text indicating that setting the number of flushes to zero effectively disabling RBI is misleading. Alternatively there may be a bug in the software.

I haven’t included any logs but can do if you feel they will be of value in this instance.

Sincerely,
Niall MacNeill
Wattle Flat, NSW, Australia

2

Logs would definitely be helpful to see why SGP thinks that it should be running the flash:

Jared

3

Thanks Jared,
Here is a DropBox link to a folder with the images I took with MaxIm DL, The SkyX and SGPro. You can see the times when the images were taken and correlate them to when I turned the pre-flash on and off in the various programs, in the log file.

Here is a link to the log file:

Cheers,
Niall

4

Hi Jared, any joy with this one? I have managed to land up CCDOps on my desktop, so at a pinch I can use that to turn RBI pre-flash off, however, it would be better if the option to select 0 flushes would actually disable it.
Thanks, Niall

5

Hi again Jared,
Firstly, I just want to acknowledge the huge benefit I am accruing in the use of SGPro. Its use is a watershed in my deep sky imaging and it is quite the most useful astronomy software I know of and/ or use. Congratulations on the development of this incredibly useful tool for astro-imagers.
Secondly, did you make any progress on the RBI pre-flash issue that I identified for the SBIG 16803 and in particular the inability to turn it off? I can get by in that I normally don’t use RBI pre-flash, but should I ever need to I would have to bring the camera inside and hook it up to my desktop, then use CCDOps to turn it off. CCDOps doesn’t work on my observatory laptop for some reason. I would just like to understand if you realise the problem and where it sits in your priority list for a fix.
Many thanks, Niall

6

I am having a similar issue with an SBIG STT-8300 camera. SGPro can turn the preflash on but will not turn it off. I can turn preflash off in CCDOps before running SGPro so that it does not come on during my imaging sequence.
I did a test the other night where I took an image in SGPro with the preflash off and then turned it on to take another image where I saw artifacts from the preflash. Finally, I tried to turn preflash off by setting ‘count’ to zero before taking a third image. I still saw artifacts from the preflash in the third image. When I check the log file I can see where I went in to the camera settings to turn preflash off but there is no record in the log file that I did this or of it being turned off.

7

Pretty much the same for me Stuart. I then found CCDOps wouldn’t load on my laptop. There is some .dll file corruption from Windows 10 so it just disappears when I connect the camera, I ended up at Diffraction Limited’s suggestion loading the 30 day trial of MaximDL and from there I was able to turn it off. I have run CCDOps on my desktop, so at a pinch I can bring the camera inside to connect it up and turn it off.
I haven’t need to use the RBI pre-flash, except for initially accidentally turning it on when I was playing around with settings and then not being able to turn it off.