DeepSkyStacker - advice for a beginner

[Brushman]

Just starting to play with stacking in DSS and I'm  looking for some advice for a beginner...

I inputted 60+ seconds of light frames but after I 'check all' and 'register checked pictures' it is supposed to display the total exposure time - as seen in tutorials I've watched - but mine just displays a '-'. No figure at all. 

I inputted 82 lights (0.77s exposure for each) however the final stacked image data shows at: 10s exposure (14 frames). Why is this? Is it disqualifying the majority of my shots? If so, is there a breakdown I get to see anywhere? 

Full disclosure - the images aren't great so this is most likely the issue, but I can't seem to find an answer through research so I'm turning to the community for clarification! 

(And I know I should be aiming for much more data, both quality and quantity - but my setup is very basic for imaging so I'm just playing and learning before upgrading.)

Edited January 12, 2020 by Brushman

[wxsatuser]

Think you may have answered your own question.

Such short exposures may not be recording much, just a guess mind.

[CloudMagnet]

DSS stacks images by looking for stars and matching them up in each picture to layer them over each other. So if the exposure is low you wont have enough stars in the picture for this to work. Also, I assume that you are not using tracking given the low exposure you are using? If the stars are not round then DSS won't be able to detect them.

When you have checked all your pictures, use the advanced setting "star detection threshold". Clicking on compute will show you how many stars DSS is finding. You want at least a few dozen to make sure there is enough stars.

[happy-kat]

Only 14 of your 80 frames are being used. Run register again and change the star threshold level. Out of focus stars won't be easily detected.

[Brushman]

2 hours ago, CloudMagnet said:

Also, I assume that you are not using tracking given the low exposure you are using?

No tracking unfortunately - my go-to mount is knackered (thread for that here) so I'm manually tracking and shooting short exposures for now.

I really just wanted to collect something to trial stacking. Perhaps nightscapes would be a better way for me to trial stacking as I can capture longer exposures from a static tripod? 

 

[happy-kat]

If your nightscape includes a static foreground then Sequator is better to use as you can define your foreground area.

[Brushman]

Sequater looks great - thanks for the tip 👍

[philhilo]

From experience another reason DSS can baulk at a set of subs is having one that is radically different to the others - it has happened to me more than once when I have shot multiple targets and got an image into the wrong batch. DSS then only processed a few of the subs, got to the different one and didn't do the rest. Very baffling till I went through the subs when more awake!