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Posts posted by bendavidson

  1. Re: light panel, tried morning twilight for flats and it was fine.  Must be the light panel, although it's been suggested it's the power source rather than the panel as such - will check that out before getting a different one.

    Re: image controls - thanks; kicking myself!  Don't know where I got the from that they made no difference, but glad I know now and won't [removed word] up more captures by playing around mid-sequence!

  2. On 9/23/2016 at 08:39, rwg said:

    Try using minimum gain and a longer exposure for your flats -  that effect looks awfully like the banding you get on some webcams under 50/60hz electric light, so I'm suspecting that your light panel varies in brightness over a short time period and maybe a longer exposure would help average that out.



    I thought that too, but until just now was under the misapprehension from the guide notes I've been using here that I needed to ensure the gain on flats was the same as on darks.  

    I'll try lower gain, longer exposure and see if that works.



  3. On 9/18/2016 at 21:16, rwg said:

    Definitly looks like a processing issue as there is no sign of the stripes in the stack with no flats. Also the 3d look in the region of the dust donuts is very odd.

    I think you might get more help in a processing thread as I haven't really got as much expertise to add in this field. What happens if you use your flat frame as both flat and light frame? In theory that should give you an even gray output I believe.



    Thanks Robin,

    Looking at the screen grab and capture below, I think the issue is likely to be the type of light panel I'm using.

    Would value any views but I don't think it's a SC issue...




    Flat screen grab.jpg

  4. One more question for now...

    This stacked pic  was from a series of captures of the pinwheel galaxy - gain was too low and the moon was full, so poor quality pic generally, but there's something seriously wrong with the flats - any idea what is causing the banding?  I'm worried I've just got the wrong sort of light panel but hoping there's something in the SC settings I can adjust.  Flats were 1/500th of a second.

    (Stacked pic without flats also attached)





  5. 2 minutes ago, rwg said:

    The histogram button is in the toolbar - just to the right of the zoom control and to the left of the focus tools.


    Thanks - I did try that but was not the format I expected - showing a separate line graph for each RGB colour instead of a single block.  Will try again shortly.

    Any chance you could please show me a screen grab of what it looks like for an optimum flat capture?  Thanks as ever in anticipation...

    PS I tried to use the focus tools, but SC crashed - did I read somewhere this is a bug you're working on?

  6. On ‎10‎/‎09‎/‎2016 at 18:34, rwg said:


    If you are seeing the frames on the screen then the USB cable is fine - the failure to save is likely just a bug. Can you  let me know the exact setup the next time it happens (capture settings file, how you were trying to capture and if possible the SharpCap log too).



    Will do.  Thanks Robin.

    Just out of interest, what does the Turbo USB control do?

  7. Hi all,

    I'm periodically getting the same problem reported a while back where frames aren't saving when I try to do a series of captures - the 'camera settings' files saves but not the image files.  I assume it's because I need a USB cable direct to the PC rather than via a powered hub.

    Just wondering though what the Turbo USB control does and whether it might make a difference?

    Thanks in advance.

  8. On ‎04‎/‎09‎/‎2016 at 17:59, rwg said:

    Yes, what Neil says is the best trick to finding the right bayer pattern. Two will still look blocky, two will have smooth colours, but only one of those will have the red and blue the right way round.

    Another trick is to use a red laser pen - don't shine it straight at the sensor as I have no idea if it could cause damage, but at a sheet of paper over the sensor maybe. You'll know you've got the right pattern when it comes out red :)


    Thanks Robin.  Yes, was straightforward once I had that advice.  Appreciated.

  9. On ‎04‎/‎09‎/‎2016 at 14:02, Stub Mandrel said:

    Take a short sample image of some everyday colourful object.

    One of the settings will render the image more or less right, all others will be way out (none will be spot on as an astro camera doesn't have auto white balance). You might find using a red, green and blue target makes it easiest.

    Thanks Neil.  On that basis it's GRBG for me.  Is that some hardwired setting in the ASI1600?  Just interested as Robin suggested BGGR...

  10. 49 minutes ago, rwg said:

    Your capture file is only 8 bit, so DSS isn't debayering it for you. You could go for RAW16 and re-capture, or you could work with the data you have by using PIPP.

    I got your FITS file to debayer in PIPP with the following.

    * Add it to the source files (you can add multiple files here)

    * Go to the input options tab, Tick the Debayer Monochrome Frames option and choose BGGR.

    * Go to output options tab, select fits output.

    * Go to the do processing tab, click start processing

    That creates a colour FITS file you can open in DSS.




    Thanks Robin.

    I've got SharpCap saving in Raw16 and I think DSS can now use that data.  I'll check again once I've got clear skies, but I can see colouration on the hot pixels coming through.  I'll use PIPP with those settings above if something goes wrong though.

    Really appreciate all your help.  

    While I think of it, why BGGR  rather than the other options?

    Thanks Robin.

  11. Thanks Neil.

    I'm pretty sure I understand what you're saying - I have been stacking and using curves in CS2 for a couple of years so know that's what should happen - but the final image DSS saves from the SharpCap subs appears to have no colour.  The SharpCap subs themselves seem to have no colour.  Seems like for some reason the debayering is not working.  Here's an example of a single subframe and the image settings from SharpCap.  I expect there's something obvious and daft I'm doing wrong, but I can't spot it!



  12. 2 hours ago, rwg said:

    Those are the right settings for forcing Debayer in DSS, but I do wonder - it does say '16 bit FITS files' - are you capturing at 16 bit depth? If not it might be that DSS is ignoring the settings?

    Thanks Robin - 

    I'm not sure - I've used the settings you suggested in this post:

    On 8/21/2016 at 19:49, rwg said:


    Ok, let's check a few things .... Are you using RGB24 mode or RAW8 mode (RAW8 recommended).



    I think there was also a Raw16 mode - would that be better?


  13. On ‎23‎/‎08‎/‎2016 at 23:06, rwg said:


    You need to tell your stacking software (DeepSkyStacker?) to debayer the frames to turn the mono image with the grid effect into a proper colour image. DeepSkyStacker can be told to do this with FITS input images (look in the Raw/FITS settings). With PNG frames you might need to pre-process them in PIPP into colour frames.


    Thanks Robin.  I couldn't get PIPP to work so started again - saved subs as FITS files from SharpCap, then told DSS to debayer them -  No improvement though - still getting just greyscale final results.  Does this setting look right?



  14. 17 hours ago, rwg said:


    RAW8 is only one byte per pixel, RGB24 is 3 bytes per pixel - this is particularly important for the high resolution of these cameras - a RAW8 frame is about 16 megabytes, an RGB one is 48. The RGB frame doesn't actually store any more data, it's just in a less efficient format.

    Glad to hear that you are in business though!




    Hi Robin,

    Tryng to stack last night's images today, I find there's no colour data and when zooming in there's a criss-cross pattern of squares.  Is this because the subs saved in png format?  I have tried to set the default as FITS but it seems to switch back to png...

    Any ideas?


  15. 23 hours ago, rwg said:



    Ok, let's check a few things - are you using a USB2 or USB3 connection? Do you see correct images if you are not capturing (ie if you are just watching the camera output on screen)? How long a USB cable are you using? (USB3 gets sulky when the length gets past about 3.5m or so). Are you using the camera via the direct SDK support in SharpCap or via the ASCOM or Webcam driver (last two not recommended). Are you using RGB24 mode or RAW8 mode (RAW8 recommended).



    I'm using USB3 connection from the camera to the hub, and USB3 from the hub to the PC.

    The camera output on the screen looks ok - it refreshes at the interval set (or at least it does now that I'm using SharpCap 2.9), and the hot pixels change from image to image and there are more of them the longer the exposure.  (Cloudless night tonight so will test against the sky later!)

    USB cables are both 2m.

    I'm using the top menu option (Manufacturers sdk I think).

    Using RGB24 mode, the default.



  16. 17 hours ago, rwg said:

    Hi Ben,

    are you really using 2.8? 2.9 would be a better bet for the 1600 cameras as it has an updated version of the ZWO SDK which should give better support for those cameras.



    I've downloaded and installed the latest 2.9 version.

    The bug is still there - if I use a USB powered hub nothing is captured (or at least nothing is saved); if I plug the USB cable straight from my camera to the PC, Windows freezes as it appears to be saving the captured image and I have to do a hard reboot.

    Any ideas?


  17. Hi Robin, thanks for the programme and support.

    I've installed Sharpcap 2.8 and managed to get it to connect to my ASI1600MC.  I can change settings and switch on and off the cooler from Sharpcap, but when trying to capture stills the computer freezes.  Earlier when connecting via a USB hub the status bar looked like it was capturing, but  only the capture settings file saved and not the actual image.  The freezing issue occurs when I plug the AZI1600 direct into my Windows 7 PC.  After several tries the PC is now freezing as soon as I try to select the camera.

    Anything obvious I can try to fix this?



  18. Thanks - yes, marginal difference in the end, but good to understand how you made the numbers work. With a 9.25" SCT and 60mm Altair guidescope and cam, I end up with a ratio of 8. I'll see how well it does and maybe add a Barlow lens. Adding a 6.3 focal reducer takes the ratio down to about 6...

    Once again thanks - really good article. The setting up walk through was excellent and I'm sure you're right it made more sense to do it indoors rather than outside in the cold, even if there weren't hitches...

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