Tom OD

I ve had this same issue and it’s ended in a re shoot in a few occasions. It’s worth going through each of your 30 subs and checking the background values. Maybe sone passing thin cloud in a few frames has messed up the overall stack. Certainly shooting with a moon about won’t help, but it might be a rogue frame or two. I can’t remember if I found an issue when I had this problem. I can think of three times it occurred, so as I said I m afraid I reshot the panel in question. Tom

Bloody hell that’s a lot of dust. Great capture. 4 pane mosaic and barely a whiff of dark background space in there. T.

Olly put the light panel on the scope, and at its lowest brightest setting. When I started taking pics, it was giving white pixels on the lower part of the chip through a gradient to black pixels at the top of the chip. After adding in the paper sheets, I was able to take exp to 1.3s, and the gradient started to disappear and become uniform. The dust bunnies then wold show. It took a few sheets of paper to get it to the point where the LRGB were a few seconds long,which gave a good gradient across the flat. Ha flat then become about 20s With these settings, the ADU was approx 20,000 of the full well depth, which I m happy with as 55k is the stated full max. Tom

Hi Alan I just started imaging leaving the camera on power Save, and Low as the settings. Sorry I still have to mail Atik, I got very side tracked, and started on a new mosaic. I m not sure how to write a review of the camera, but I can say that the FITs are very clean. My old 11 meg had a lot of pixels, and bad columns, so each file of the camera is a joy from that point of view. I have been taking 2hrs worth of Lum frames, where normally I would have taken 4hrs of Lum for each Lum pane. In my new 2hr frames the data is clean (so far without flats) and the data of the dim background dust is very evident. I have not taken Ha or RGB frames yet, I ve been just running it for the Lum frames. In short I m very impressed with the camera. The system still has tilt, so I cant give a proper account just yet, but in a mosaic the end downsized frames will not show the tilt issues, especially after the overlaps are blended. The chip is o sensitive that taking flats is tricky. The Ha flat at 6 secs show s agoo even light frame. The lower 0.1s flats for the other filters, are giving bright to dark gradients across the chip that are unusable. So you need a dim flat field box I think to get flats with this chip. Tom.

Try SCNR on the full image, it might only adjust the middle section. T.

Great shot given the latitude. It might be a bit green on my screen in the centre, but you nailed the contrast I think in the dark nebula areas. Tom

Jeez, thats a lot of signal for 2.5hrs per panel approx. Small stars too! super job. Tom

Yes the low gain value is 0 as per Astroart header data. I haven’t written to atik yet as I wanted to get the tests done first so that I can word my mail correctly. I ll send it this weekend. Tom.

Good thinking and yes the values are there. So even though the manual says the Gain goes from 0-35 the Medium and High have much higher values.

Thanks Alan. I was looking at the main gain setting in SGP, but I was not aware of the Cog wheel second option, so thanks for that. I'll add in the meta data to the files too, its good info to have. I'll let the Ascom driver start with the Power save and Low, and go from there for starters. Tom

So a few things must be happening here. Either the Atik amp works differently to ZWO, the most likely I would think, or the software is controlling it differently. Given the chips are all from Sony, I would think that any specific silicon P/N gate signal or what ever it the correct term, will be the same. So any cliff in voltage signal should be the same for all further cameras manufacturers. My data is not showing a cliff anywhere in the Std Dev. (We are taking the Std Dev in ADUs as the Read Noise here in Bias frames) Now the Atik manual is very vague about settings that "PowerSave – This mode allows the camera to shut down non-essential circuits during exposures" Who knows what this means. Maybe Atik are reading this thread and enjoying our struggle here Tom

Yes its fun taking and plotting the data and seeing what the cameras does. Is HCG normal in all other CMOS chips? I dont know, or is it only dependant on how the software reads the chips, sets the gain etc... Tom

Yes a full frame planetary camera seems counter intuitive. Increasing the offset to stop clipping makes sense as I read it. Thanks for all your inputs here. I think its lead me to the Low setting, and Power save. That suggests that it'll also keep the full well depth high. Unless I m chasing super dim nebula, I wont change those settings. Tom

No there is no mention of what the gain and offset values are actually running at in the preset modes Low Medium High. However given the Background values that match the closely the ADU, it looks like they run at 200, 400, 1050. So maybe as the manual says, the Power save, Normal and Fast which show very little differences are like the USB speed in your ZWO menu. I can see how Fast would allow lots of frames to downloading to beat the seeing. I m at a loss to explain the Medium and High Presets though. Looking at the Medium and High frames though, the 0 ADU seems to correspond to the lower x axis, yet the offset appears to be at the 400 / 1000 mark. I guess either the gain is maxed out, and / or internally the s/w is doing something to the chip causing the data to get clipped on the Min values. Very confusing. See attached Stats FOV from the Medium Preset setting on Normal Mode. Tom.

Here are some more results from todays tests. Taken at room temp, and an offset at 400 for the table of varying Gain values. Then I tried different "Power" modes. The Power Save is not the lowest noise / SD value as the manual states. All in all I think it might be best to just go with the Power Save mode, and Low settings that Atik set. There is no obvious HCG cliff in the data as in the ZWO settings. Tom

Yes I should that with all the settings and see. I'll wait for Atik to reply first I think. The fridge is now full of food

Maybe this is the HCG equivalent? I had it set in the capture program for the test shots.

Thanks for your reply Alan. I'll mail Atik and see what they say. It would be good to know exactly what their presets do to the camera. Its hardly an Intellectual Property thing?! I certainly didnt get anywhere near your 12 SD values, so as you say maybe it was always On, or On from my "Power Save" selection. Yes my 1000 is way to high on offset I think. I'll drop that by at least half. Tom

I managed to borrow a 12v mains power supply that gave 2.5A Not quite the 5A needed to use the full cooler. So instead I put the camera in the fridge, where the sensor thought it was 11C. It was in there for over an hour and cold to the touch. I would have thought it would have been 5C approx. Anyway here are the Bias results using Noise Evaluation script in PixInsight and Statistics in AstroArt6 So first thing to note is the difference in both programs seeing the noise at different Gain settings. If you assume Standard Dev = Noise from the two programs. Once you increase the Offset, which I guess gives a better result on the data, as no black clipped data is rejected then the 30 / 35 Gain seems to show the lowest Noise in PI (One cell is incorrectly marked Blue as the lowest in the image offset 1000 gain 30), but 0 Gain is the best in AstroArt6 So very confusing, I m none the wiser which would be best. Especially given that the Atik manual suggests dont go over 30 on the gain. From the data the AstroArt6 Standard Deviation is a straight increase line. The Noise script gives an "M" shape for all 3 offset data sets.. So I dont know about HCG on this camera. Anyone want to give an input to the data? Thanks Tom

I had the cooler running to -15c from the car cigarette lighter port. It did download a few 300s the very first time I tried the camera. so can’t say for sure what hung the software on this second attempt. I d rather test with the cooler running to get done graphs so I just may have to go get a 5amp rated 12v mains power supply as it could be a while before I get out to the observatory. I d like to be a little bit familiar so I can run it remotely once I get home. Tom.

Ok well attempt one has sort of failed. I did manage to get the camera to connect in SGP, but it failed to save any Bias frames. So I went to Dusk which I downloaded, and it wouldnt connect to the camera. Third go was getting Artemis to connect, and it did. In the exposure settings there are the settings that match what SPG and the download manual sees. However it hung flushing a frame and I had to quit the program. So no bias frames were downloaded. At that point sitting in the idling car the battery on the laptop started to fail. Very odd behaviour all around. I really need a 220v AC adapter that can give 5amps to test this properly. Disappointing that this was not supplied with the camera really. Anyway at least the Artemis and SGP has the settings visible and changes can be made to them. Tom

Thanks for all these great ideas. I'll do these tetss and post my results. Thanks Again Tom

I don’t even think there ever was one. It used to be a firmware change that you installed and you could set the power by setting the percentage I think. It was so long ago I can’t remember. However I don’t think it ever showed up as on anywhere in the software.

Ahh thats great thanks. Good to see the explanations of gain and offsets. I imagine thats the most asked question from newbie CMOS imagers. I think I'll be taking lots of test shots to figure out what suits what objects. I didnt get the allen keys or the desicant tool in the box though. Luckily I have plenty of tools at hand. Tom

It might I use SGP as the sequencer, so maybe its buried in there somewhere under the camera settings / mode.