DSS weird behaviour

[john2y]

Hey guys, 

I just got my Canon 600D and yesterday when I wanted to test it I made 60x45s subs + 20 darks. Everything went well till I wanted to stack it in DSS, it was making just a narrow image. So after few minutes of googling I found out that I have to get newer version of DSS 3.3.3 and that fixed the problem but here is another one and I don't know what causes this one. When I stack the images it goes exactly like when I was stacking images from my Canon 100D but when it gets to computing final image it starts to count the stars and it detects thousands of stars (80 000) and the final image is plain white and when I stretch the histogram nothing happens. I know I can reduce the star detecting treshold but I tried it and it didn't make any difference. Also when I try the star detection before stacking it detects around 40 stars which is normal. Any idea what could be the cause? 

Thanks, Jan

[happy-kat]

You need to use DSS version 3.3.4 which I think you have now got.

Trying to understand your remaining question.

[john2y]

First of all I'm sorry I just noticed that I've posted this to the wrong section. I wanted it to software disscusion but back to the problem. It doesn't matter if I use DSS 3.3.3 or 3.3.4 it does it on both versions. Picture will probably explain it better than I can since english isn't my native language. It stacks everything in 10 minutes and then it's registering the stars for another 30 minutes.

During this the star detection treshold was set to 17% and it detected 43 stars when I was testing it. When the registering finishes it starts again from 0 and it runs in loop and after about 30 minutes it ends.

[DougM43]

I'm no expert by a long way but in the register settings there's a star detection threshold slider, perhaps lowering the percentage would help, 

Doug

[happy-kat]

To not get a narrow final image you will need to use 3.3.4

Your stars have lots of trailing looking at the FWHM column this might be your problem, noise is being recognised as stars hence the 80,000 is my thought

Your English is very good.

Could you post a png of one of your images so we can look please?

[john2y]

Truth is that yesterday was kinda cloudy and today I was just quickly testing if everything works but it still detects only 50 stars before I stack it. What image do you have in mind? Sub frame or stacked?

[happy-kat]

A light frame to look at star shapes. DSS can be funny with none round stars. Png file type can be seen in a post.

[Thalestris24]

Hi

Can you post a single sub (as jpg or png) so we can see the image quality. What equipment are you using to take your images? I see your exposure time was only 19s which seems a bit short but maybe you have dark skies!

Louise

[john2y]

This is one sub that I used and before you tell me that the stars aren't perfectly round, I know but I stacked much worse without any problem. I'm also attaching the tif file that was made just as a test from three subs. It is completly white and when I open it in photoshop and convert it to 16bit using exposure and gamma I can't stretch histogram. It's really weird as I said. 

 

Autosave.tif

[john2y]

Problem solved! 

turns out that DSS was doing these things because I was using Auto Adaptive Weighten Average. When I switched it to Kappa-Sigma clipping there was no problem with too many stars or the tiff file. Anyway thank you everybody for your help! 

[happy-kat]

Yey well done. Your stars didn't look so bad either on shape. Will you post your final image on m31.

[john2y]

It is actually M81 and M82 on the side.

[happy-kat]

A result. Sorry yes my guess was rather out on the target!