Amp glow

@mannymo63

Hi Manuel, what camera do you use? Normally amp glow can be processed out by using the correct darks. What exposure time, gain and temperature were the lights and darks taken at?

Thanks, Wouter

ZWOASI294 PRO, 120g/300s subs/-10*

Yes that camera is notorious for its problematic amp glow. I have read reports of many users on several forums who were struggling with the amp glow produced by this camera. I am not sure how to solve it unfortunately. Maybe the ZWO forum can help you? In any case, this is not an APP thing but really related to the camera. 

Wouter

And how does your masterdark look like @mannymo63 ?

@wvreeven

I’m currently redoing all my calibration files and will also make masters according to Sara Wager tutorial video. I will follow up afterwards. Yes, I’m aware of ZWOASI294 PRO reputation with amp glow, but my main issue is trying to process it out. I will also visit the ZWO forum. Thanks😊👌🏾

@mannymo63

Good idea to redo your calibration files. It is very hard to process it out once it slips into your image integrations. I hope the new calibration files solve your issue.

Wouter

After processing a picture this is the results. I have a huge spike in the upper right corner. I dont want to crop it due to cutting out the subject. The other picture is straight off of ASI AIR (non-processed). I've redone my master calibration files using Sara Wager's video tutorial and do not believe I've done anything out of order. This is killing me

So can you show a screenshot of what your masterdark looks like? And also check if the adaptive pedestal is on in tab 2, normally this is the case already.

I have the same camera and yes it has bad amp glow I would say but its easily calibrated out with proper dark frames. Just make sure your darks are the same temperature, gain, offset and time. APP does a great job of calibrating out this amp glow.

EDIT: Even if your exposure time is not the same, APP can scale the dark and still do a good job of calibration.

Yes, APP is indeed able to correct severe amp-glow as well, so I'm also wondering if the calibration data is correct.

Thanks Manuel, I'll have to look tomorrow (or maybe Wouter still is up 🙂 ). We'll try to get this sorted.

@mannymo63 Ok, to be able to investigate further, could you also share a single dark frame and a single light frame?

I believe I have solved the issue. My dark flat and flat files were in the wrong folders. I produced 2 subs that displayed with no amp glow so far. Thanks for your assistance. 
Manuel

You mean you loaded them in with the wrong buttons in app?

Hi everyone,

This is about the best thread for me to post to.  I have a ZWO ASI183mm pro cooled mono and am just getting to know it, and APP.   I just downloaded the program last week.  As everyone here and elsewhere have noted, the 183 sensor produces quite a bit of glow.  I was stunned to see how pronounced it was but confident I could weed it out with APP settings suggested.  I moved specifically from DSS to APP to be able to make that happen.  I had very little luck with my first session and just ended up using the healing brush in photoshop to brush it out just to get a decent pic of the Rosette Neb.  It was taken in LRGB at Unity gain (111) and 180 sec exposures (I understand that was likely a bit much :-).  So I read a bit more and thought that maybe cutting back the gain to about 50 and the subs to 30sec, I might have better luck...

Last night, my plan was to take 60 subs of 30sec each at a gain of 50 (ended up at 51.  I couldn't move the slider in small enough increments) in each channel (LRGB) of the Cone/Christmas Tree Nebula.  Unfortunately some high cirrus snuck in and ruined the light subs from about halfway through red all the way through the G/B.  I did however capture 60 nice Luminance subs that I integrated via APP.  Here is a snapshot.  Note the amp glow along the right side.

I also took 30 Dark frames same gain and exposure and temp (10.4 deg). Note the same area of glow.

I have tried to get the glow out by integrating all the single darks and all the single luminance shots.  I have tried integrating all the Luminance with a single master dark.  I have tried all the darks with a single integrated luminance, and I've tried integrating two integrated master luminance and master dark.  In the 2) Calibrate tab, I have the Adaptive pedestal reduce amp/glow box checked.  Still no luck.

I've read in numerous places that having that box checked in APP should get rid of the amp glow.  I obviously have some other box checked or not checked that is causing this not to work.  Anyone have any pointers or a work flow I can go to?

Also, maybe I'm not cold enough on the camera???

Thanks,

Jeff

That glow shouldn't be a problem at all. So my guess is that there is an issue with your dark frames. Do you take them at the same temperature and everything as the light? Offset is positive as well etc?

Thanks for replying Vincent.  I truly appreciate it.  I will go back and make sure I look at everything. 

All I do is take the lights, then move my equipment indoors to a dark room in my home and then shoot the darks.  I don't touch the camera "settings" in APT.  I put the lens cover on in the dark room, confirm APT settings are the same for the exposure, binning and number of frames (I shot 30), cool the camera to the same setting I had when outside (10.4 deg F), and press start.  I don't mess with camera "settings" for gain and offset, leaving them as they were when I shot the subs.  I have never actually opened the "settings" tab to confirm the settings stay the same prior to shooting the darks but am assuming it doesn't change if I don't change them.

I'll take a look at that and the other settings later today when I get home from work to confirm.

Thanks again,

Jeff

Yeah just to confirm that would be nice, just carefully check all parameters. If those remain the same I'll ask for some data to check myself.

Hi Vincent,

Here is a screenshot of the properties of one light and one dark from the file loading/select section in APP.  Hopefully its not to small to read when you open it.

Everything matches across the board.  Binning 1x1 on both light and dark.  51 gain, 30 sec exposure, 10deg F on both and color space 16b Gray.  I went back and looked at my ZWO settings on camera in APT and the gain is 51, bit depth is 10 USB limit is 40 (unchanged from darks to lights).  Don't know if it matters but for Image Type I have Raw16 selected.

Any clues from this data?

Jeff

No, unfortunately not. Can you share some of the data, just upload a subset (like 10 lights), your masterbias, masterdark and masterflat (if you have that).

Go to https://upload.astropixelprocessor.com and use upload1 as username and upload1 as password.

Create a directory named “jazzy1839-ampGlowIssue” and upload in there. Thank you!

Done.  For that particular session, all I have is the master dark and the luminance lights.  I uploaded the MD and 10 lights into the file.  I have a full compliment of darks, bias, flats (LRGB) and lights (LRGB) for the Rosette Nebula taken the same way two nights before.  If what I uploaded isn't enough, just let me know and I'll upload the Rosette MD/MF/MB and some lights.

Thanks Vincent.  I really appreciate the help.  Hope all is well in Western Europe these days.

Jeff

So strangely, that data doesn't show amp glow in my integration, this is the stretched luminance result (stretched to 30%BG even);

I left APP at default settings, the only thing I checked was LNC and MBB in the integration tab. I used APP 1.083 beta1

Hi Vincent,

So I downloaded the same beta1 Version, used your settings for LNC and MBB (I used LNC 1 and 1 iteration), and then loaded the same files I gave you.  Success!  Then I took all 60x Luminance and 30x Darks and integrated those.  Again, success!  Even got the Hubble Variable Neb showing up too.  I plan to take the other channels (RGB) tonight and then add flats and bias as well.  I'll iterate the process to add each individually to make sure I don't muck things up. 

As an aside, I tried the above on my Rosette shots and had the amp glow really bad...I don't get that???  But, success a little at a time 🙂  My integrated 60xL/30xD jpeg below.  Thanks for the help.  Hopefully I'm getting past this hurdle...

Jeff 

Excellent! For the other data, that would be a different question again, it all depends on type of data, quality of the calibration data etc. But yes, you should be able to handle this amp-glow easily, so that would point to something in the data maybe.

Hi Vincent,

One last issue that I hope is not APP related.  I took 240 subs with the 183mm pro mentioned above.  51 gain, 30 sec exposures, 60 each LRGB, binned 1x 1 at bit depth of 10 and 10 degrees.  I stacked with 20x darks and there was no amp glow...yay!  However, there was also little to zero color in those images.  And when I say little, I felt like I was imagining a slight bit of red tint.  No matter what I did, I could not get any color.  I integrated all channels one time and tried it, no color.  Then integrated separate channels and tried it, no color.  I moved to the processing side and stretched and twisted my way through every slider.  Still no color.  Am I just taking too short of exposures at too low of a gain setting?  I can't think of any other settings I may not have checked correctly in APP.  I am using all default settings except for what we talk about above.  I thought that after I integrated and the image came out there would be some color.  I even saved the integrated files as a tiff and moved to photoshop.  Still nothing.

I downloaded the integrated file in the above directory.  If you have a moment, can you give it a look and see if you get any results?  Any pointers before I move on would be great.

Thanks,

Jeff 

30 seconds is indeed very short, so that doesn't surprise me a lot. I think you'd get way better data if you go for as long as you can, with fewer subs. Try 5 min next time. Also, adding Luminance will suppress color, so make sure you don't add 100% to the luminance channel. Mabula is going to have a look in a later version to see if he can make that work a bit better.