How To Drizzle In DSS

[groberts]

Thought I'd try using drizzle in DSS with a few narrowband frames from a brief M20 last might before the clouds rolled in - again!  I have not used this before but registered the subs and calibration frames as normal, then after checking the x2 Drizzle option went to stack but got the report: The selected drizzle option not compatible with the Bayer drizzle mode.  Not sure what this means / what I have dome wrong, as there seems to be no other options.  Any ideas please?

Thanks, Graham

[Stub Mandrel]

Perhaps you have bayer drizzle mode switch on in RAW/FTIS DDP settings AND are trying to use drizzle stacking.

It won't let you drizzle two different ways at the same time.

[groberts]

Thanks Neil, I think you're right but this appears to be the default if the 'Monochrome 16 bit FITS files created by a DSLR or a color CCD camera' is unchecked  for mono CCD etc subs.  

How can I therefore apply x2 or x3  drizzle etc to CCD subs in DSS or can you not use that function then?  

[red dwalf]

I found that when I tried to drizzle using DSS, it would throw a wobbler saying not enough memory, or something like that, but if I draw a 2 or 3 X box around the area of interest, i.e. click on the image and drag a box around the area, it would use the drizzle mode no problem, does a good job too at rounding stars off.

[Stub Mandrel]

9 hours ago, groberts said:

Thanks Neil, I think you're right but this appears to be the default if the 'Monochrome 16 bit FITS files created by a DSLR or a color CCD camera' is unchecked  for mono CCD etc subs.  

How can I therefore apply x2 or x3  drizzle etc to CCD subs in DSS or can you not use that function then?  

If you have a mono FITS file  it  shouldn't be debayering at all...

[groberts]

OK thanks Neil, this has got me thinking that the FITS settings in DSS are not correct.  I am in the process of transitioning from DSLR RAW files to mono FITS files using a ZWO1600MM-Cool camera and maybe need to make some more changes to the settings?

Below is a screen shot of my current settings for FITS.  When I first started with this the top Mono 16Bit  box was checked and caused havoc! I unchecked it but you'll see below the Use Bayer Drizzle Algorithm box remains checked.  Do I change this to say  Bilinear / what are the correct setting for this page for my mono FITS files?

 

 

[Stub Mandrel]

I've never used mono, but being greyed out suggests those settings are not available/inactive.

I think you need to make sure the 'register' and 'stack' dialogues are set for mono.

[groberts]

OK using some new data on the Witch's Broom taken earlier this week I set the Drizzle x2 in DSS stacking, having changed the FITS Files from "Use Bayer Drizzle....." to "Bilinear Interpolation", which was greyed out anyhow + used relevant Darks + Bias + Flats calibration for the respective Ha and OIII subs.

After Registering the Ha stacked well with drizzle and with a bit a stretching, in my opinion looks better than the non-drizzle version. See below (1 = drizzle 2 = no drizzle):

     

However, when trying to stack the OIII subs in exactly the same way with the OIII data and calibration, I just get a big yellow error message! after running though the initial pre-stacking process (see below); note that without the Drizzle function the OIII stacks OK. Any ideas what's happening or what have I done wrong? 

Thanks.

 

 

[Stub Mandrel]

I've never seen that :-(

[groberts]

Been trying to process again from scratch.  

To recap - the Ha subs stack OK and produce a good image but not the OIII subs.  On running again same result with the OIII subs when stacking after registering:

(i) creates masters OK

(ii) runs through stacking sequence OK (

iii) goes through the final Computing Final Picture sequence and crashes at the very end with the aforementioned yellow triangle and ! mark

Ideas on how to resolve greatfully received + thanks.    

[Stub Mandrel]

Sounds like a memory crash?

If you are using drizzle, did you remember to select a selection and tell it to use it?

[groberts]

2 minutes ago, Stub Mandrel said:

Sounds like a memory crash?

If you are using drizzle, did you remember to select a selection and tell it to use it?

Could be, don't understand the point re. select the selection, please can you explain?

Can anybody direct me to a tutorial on drizzle with FITS files.  I've been using DSS OK for a few years but transitioning to the ZWO1600 mono and Fits files is a whole new ballgame, as usual!  Youtube if possible.

Thanks  

[kens]

32 minutes ago, groberts said:

Could be, don't understand the point re. select the selection, please can you explain?

Can anybody direct me to a tutorial on drizzle with FITS files.  I've been using DSS OK for a few years but transitioning to the ZWO1600 mono and Fits files is a whole new ballgame, as usual!  Youtube if possible.

Thanks  

Drizzling makes the images 4 to 9 times bigger so it is normal to select a part of the image to drizzle and stack to avoid running out of memory. To do this open an image the use the custom rectangle mode over on the right. Once clicked you can rubberband a region of interest on the image. DSS even shows you the boundary that will result in the same amounf of memory at 3x and 2x drizzling.

[groberts]

Thanks, I think I understand the principal outlined but can you help me find the "custom rectangle" - on the right of what & in which location?

[groberts]

Just found a Chinese video tutorial! Can see the rectangle but which image do I apply it to if I have say 20 suns to stack - the best one?

[groberts]

I may have cracked it? Anyhow guided by above comments and Chinese tutorial drizzle now seems to work I think!

 

 

 

[groberts]

The drawback with the method outlined is that it only allows a section of the original sub to be selected using the Custom Rectangle and not the whole image, or is this normal and just an inevitable consequence of using Drizzle?  Did a quick test with just a few subs from NGC 6960 earlier this week and it seem to be OK, will try it on larger number of subs later.    

[red dwalf]

that seems to be normal, if you don`t use the 2x or 3x box it fails to stack stating memory problems or something like that.

[Stub Mandrel]

2 hours ago, groberts said:

is this normal and just an inevitable consequence of using Drizzle?

It seems to be, DSS just runs out of memory otherwise. Sadly there doesn't seem to be any ongoing development as a 64-bit version would probably be able to drizzle a full 12Mb image.