No picture showing in DSS

[Johnboy]

Hi folks,

I am very new to imaging and have a problem which isn't helping the learning curve!

I know my set up isn't the best for imaging yet, but will be adding bits as money allows. Currently I am using a CPC 1100 (fork mounted - no wedge), a 6.3 FR and a one shot colour CCD camera

Last night I thought I'd have a go at M1. With my telescope being Alt Az mounted I know I am limited to exposure times so I thought I'd try 120 x 26 second exposures. Everything looked OK on the laptop screen whilst doing the imaging run and the resultant images look fine individually, (by fine mean quite a faint grey smudge but with some shape and detail) but when I come to stack them in DSS (using the default settings), I end up with the RGB levels window showing but no picture. If I try and save it I get a message saying that there is no picture to save. DSS goes through all the motions of stacking but I end up with nothing.

I know more data would help but surely I should get something. Or am I doing something wrong? Any help would be greatly appreciated.

Thank you,

John

[Jannis]

When it's done processing, it shuold say how many frames have been stacked over the image. It sounds almost like it haven't stacked any frames at all?

How many stars are detected in the frames? If you ahve any startrails DSS won't detect the stars, and won't stack the frames.

[Johnboy]

Hi Jannis,

Thanks for your reply. In the Star Detection Threshold window it detects 23 stars. (I have it set to 2%.) When it stacks it says it is stacking 78 out of the 120. When the stacking is done I get the RGB/Luminance/Saturation window but no picture. Also I am unable to use any of the sliders and it says there isn't a picture if I try and save it.

Regards

John

[Jannis]

In the processing window, over where the image is supposed to be, to the left, it's supposed to say how many frames were actually stacked.

I'm guessing none were actually stacked in your case, because;

2% is extremly high. I rarly have mine set to anything higher then 10% (lower % is higher detection). So high in fact that it's more likely DSS is detecting random noise as stars at this level, instead of actual stars.

Usually there is 2 reasons for this problem:

1. stars have trails so DSS don't detect them

2. out of focus, and DSS therefor won't detect them.

Can you upload a single frame so we can have a look at it? And preferably a 100% crop to see how the stars look.

[Johnboy]

Hi,

I tried changing the star detection threshold to 20% which found 6 stars. I then changed it to 5% which found 23. Both times DSS went through the registering and stacking routines but still with the same result. It says it is stacking 50+ pictures but there is nothing at the end of it. I'm not sure how to upload pictures here. There doesn't seem to be the option umless I'm missing something!

Thanks again.

John

[Ewan]

It could be the RGB Align option in the stacking options, i had the same problem when i first used DSS then i remember changing some of the stacking options but cannot remember which 1, worth a try though, try stacking 5 images as a test to save time while testing options, i assume you DSS didn't even save a file called Autosave.tif ?

[Jannis]

Odd. It sill sounds to me DSS isn't really stacking anything. If it detects noise as stars it will attempt to stack them based on teh frames score, but will end up with 0 stacked inages as the "stars" (noise) obviously won't align.

I've ended up with useless pictures from DSS, and completly while pictures, but other then that teh only time it have failed to stack any is when i've had startrails or out of focus stars.

What stacking options do you use in DSS? I'd still love to see an example frame to confirm if this is the cause or not before messing too much with the recommended settings (as they usually, while not giving you a perfect result, at least give you a stacked image).

When you click on reply, click on "more reply options", then you come to the full reply page where you can attach a file (it's a button right under the window where you type in teh text)

[Johnboy]

Hi ,

Thanks for taking the time to help me. I have attached one of the 26 second exposures. Hope this helps. At 26 secs. should there be a hint of colour at this stage or does that come in after a successful stack? Nothing was saved anywhere. I just get a white screen and if I try and save it, DSS says there is no picture to save.

Thanks again,

John

[Jannis]

At first look it looks a bit out of focus, so your stars are very soft and covering many pixels. Did you use a focusing mask to take these frames? I strongly recommend to use one, as you then get perfect focus within a few sec.

DSS is expecting to see stars covering only from 1 to a coupple of pixels, while the stars in your frames are soft and covers several pixels.

DSS therefor thinks your actual stars are sky-background/nebula, and don't detect them as stars.

I do however see a whole lot of what appears to be hot pixels in your frame, wich is what i'm thinking DSS is picking up as stars and are trying to stack (a rought count of them matches the number of stars you said DSS detected).

This obviously won't work very well.

I think your only way to stack frames looking like that, if you can't make DSS recognise your true stars, is to manually select some stars for it to stack. I think the minimum needed is 8 stars, but i'm not 100% sure about that?

In some cases when i've had slightly out of focus stars (just enough for DSS not to detect them) i've resized the imaged to a point where DSS detects my actual stars - but while this can work as a very last option on a high res DSLR, it's not realyl ideal on a low-res CCD.

Edit: as for your color, i can't really give any answer as i've never used anything but a DSLR.

[Johnboy]

Hi Jannis,

I do use a focus mask. I focused on Aldebaran then slewed to M1. I wonder if there was some mirror shift as I slewed. I will try and take more care over the focusing. Everything you say is very interesting and helpful - thanks very much. I'll have a go at manually selecting some stars and see how I go. I'll let you know!

Thanks again,

John

[Jannis]

If you used a focusing mask it's very unusual that it changed focus a lot while slewing to a different part of the sky.

It could be many otehr things too though. Like, if you had dew on your lens/mirror/sensor that could also cause it.

I'm not very familiar with low-res CCD images, like i said - but personally i have to say that it does look slightly odd out of focus to me. But I could be wrong though.

There is a way to quickly see in DSS what it have detected as stars i think.

When you click on the "select comet" button after clicking on a light frame, all the detected stars (as i understood it at least) will show up with a green circle around it after a coupple of sec for you to be able to quickly choose what "star" is the comet.

If you do that, and see only the hot pixels have a green ring around them, you know for a fact your problem is that DSS isn't detecting your actual stars.

[billhinge]

Here is your frame stretched in pixinsight, you can see it is showing what looks like the bayer pattern (sorry I don't use DSS so not familiar with its options)

[Johnboy]

Here is your frame stretched in pixinsight, you can see it is showing what looks like the bayer pattern (sorry I don't use DSS so not familiar with its options)

Hi billhinge,

Thanks for your message. Sorry for the daft question, but is having the bayer pattern showing a good thing? I still can't get any colour showing. Would it be the fact that M1 is so faint and I haven't much data possibly the cause? Maybe more data would allow more detail.

Thanks

John

[billhinge]

Hi John

I don't use DSS but use Pixinsight instead and normally calibrate and debayer before doing alignment and stacking. As far as I recall you will only have a monochrome image before debayering but someone else may confirm that?

Also I have noticed when experimenting with debayer settings that if I used the wrong matrix settings (eg RGGB, BGGR, GBRG, GRBG) then although I can I can still register and stack but I get an image that has the matrix pattern still visible. Only the correct option produces the correct result

Can you post a RAW file instead and I'll chuck it in PI

[Johnboy]

Hi,

I can't seem to find the RAW files for some reason. It looks like DSS had converted everything to Fit files. (Could be me though, but all the RAW files have become Fit's) I have attached the best image I have managed so far - it is rubbish I know - but this was got by stacking and processing just 3 of the images I did of M1 in a program called 'Nightwatch' which came with my camera. This was saved as a TIFF. I used 3 images just for speed whilst learning. No other processing has been done.

Does this help you to help me? I hope so!

That is interesting about the bayer pattern I shall check that out.

Thanks again for taking the time to help.

John

m1 from nightwatch 2.tiff

[billhinge]

It looks like the tiff is in colour. Unfortunately I don't know what else to suggest since I'm not familiar with your workflow method

Personally if it were me, I would round up all your good camera data and stick it in a new folder then either try processing it either in a different tool, or using a different workflow with DSS, or posting the zip of the folder on dropbox and seeing if someone else here can process it for you (don't be shy ;-) )

[Johnboy]

Hi,

I have found that my camera uses a CMY deBayer pattern rather than a RGB. I have downloaded trial versions of Nebulosity and Pixinsight but it looks like only Nebulosity has something listed for CMY (although this is greyed out for some reason.) Are their any other programs that might be able to handle CMY?

Also something rather more serious. I tried to upgrade the firmware for my camera but my capture program now cannot see the camera. It says it might be stuck in 'Programming Mode' but won't allow me to do anything. Has anyone got any suggestions as to how to unlock it from programming mode please?

Thanks once again.

John

[Ewan]

John, here's a run down that works for me every time.

Do not change anything in the Lower Left pane : Options, Settings, Raw/ FITS DDP Settings.

Load your images (dont bother with darks etc as we just want any image)

Click Register Checked Pictures

Select best 80% (depends on the quality of the data), Tick ALL 3 boxes.

Click ADVANCED tab, tick Reduce the noise using a Median filter, move the slider & check the quality until you get at least 12 stars.

Click Recommended Settings, Scroll to the bottom & select Use RGB Background Calibration, click OK

Click Stacking Parameters, These work for me : RESULT Mosaic, Align RGB Channels In Final Image TICKED

LIGHT Median OR Kappa Sigma Clipping

ALIGNMENT Automatic

INTERMEDIATE FILES Leave as is

COSMETIC I have the top setting @ 70 Bottome @ 50 Both Ticked.

OUTPUT Tick Create Output, check other options.

Give it a shot & post back, like i said before i have also had a white screen shot once stacked but when i first started messing with DSS so i didn't take much notice but i am pretty sure it's to do with RGB alinment options.

12 stars is enough to get stacking btw.

[Johnboy]

John, here's a run down that works for me every time.

Do not change anything in the Lower Left pane : Options, Settings, Raw/ FITS DDP Settings.

Load your images (dont bother with darks etc as we just want any image)

Click Register Checked Pictures

Select best 80% (depends on the quality of the data), Tick ALL 3 boxes.

Click ADVANCED tab, tick Reduce the noise using a Median filter, move the slider & check the quality until you get at least 12 stars.

Click Recommended Settings, Scroll to the bottom & select Use RGB Background Calibration, click OK

Click Stacking Parameters, These work for me : RESULT Mosaic, Align RGB Channels In Final Image TICKED

LIGHT Median OR Kappa Sigma Clipping

ALIGNMENT Automatic

INTERMEDIATE FILES Leave as is

COSMETIC I have the top setting @ 70 Bottome @ 50 Both Ticked.

OUTPUT Tick Create Output, check other options.

Give it a shot & post back, like i said before i have also had a white screen shot once stacked but when i first started messing with DSS so i didn't take much notice but i am pretty sure it's to do with RGB alinment options.

12 stars is enough to get stacking btw.

Hi Ewan,

Thanks very much for taking the time to set out your step by step system for me. Sadly I still have the same result. A completely blank screen at the end of the process. The window that has 'RGB/K levels' etc. doesn't do anything (i.e the sliders don't work so I can't even play around there to try and get an image.) I have also noticed that DSS crashes every time I use a setting other than 'Standard Mode' and 'Average' in the 'Stacking Parameters' area, so weather it is my PC that is conflicting somehow I don't know. My camera has a Bayer matrix of CMYG rather than RGB. Would this make a difference in the 'RGB Background Calibration' setting? I have tried different combinations of setting but I just get the same result. Frustrating!

Thanks again for your kind help, it is very much appreciated.

Best regards

John

[billhinge]

Hi John

Since you said you tried Pixinsight, did you find the CMYG debayer script?

Under Script> Batch Processing on the toolbar

[Johnboy]

Hi billhinge,

Thanks for the pointer. I will try the CMYG debayer script and let you know how I go on. The data I have at the moment is minimal but hopefully enough to help me find my way around the different aspects of imaging until I get the chance to get out under the stars again!

Have you tried 'Nebulosity'? That seems a good piece of software and more within my price range.

Thanks again,

John

[billhinge]

I think I may have missed it, I evaluated pixinsight and Maxim and ended up buying PI

Anyway, having spent the money I figure I have enough editing programs :-)