3 sets of exposures.. now what?

[LaVey]

Hi all...

I have 3 different sets of exposures, 10x3min, 35x30sec and 55x30sec, all of M31 - but at different times so are not framed the same...

When I put these into DSS it registers 100 frames (plus my 5 darks (3x30 and 2x3min), 2 flats), but then when its goes to stack them it only does 30 (my first set)...

I have tried in nebulosity to do the same but it fails to align the images correctly... Its been nearly two days of playing with DSS, nebulosity and PS but i still cant get a single image out of all my frames!

Any advice welcome.. am getting frustrated now!

nebulosity 55x30secs

nebulosity 353x30secs

dss 10x3mins

While we at it, is this normal output in DSS as well? I mean the grey film over the image? All my DSS stacks come out like this..

Again any help to a frazzled dude appreciated!!

[Whippy]

In DSS, you can adjust the star detection threshold. Try lowering it so DSS can detect more stars and be able to stack all of the subs.

WRT the 'grey film', are you using a LP filter? If you're not, I reckon that's light pollution.

Tony..

[Ant]

First make sure that (in DSS) all the light frames are checked - for some reason it doesn't seem to check them all as default.

Second, make sure that all the frames are exactly the same size. If they are not DSS won't accept them (but it normally tells you).

Try stacking with just light frames and see what happens.

I am suprised though, with 3 minute subs you should have a pretty good image.

What scope / camera / LPR Filter are you using?

ant

[Psychobilly]

The 3 sets of subs are very differernt in orientation and the framing is also vastly different between the first and 2nd sets.Whether this is apart of the problem or not I am not sure.

I have successfully combined data for M33 when there has been a 30 degree off set between the two nights data but the images were bit fairly well centered.

Billy...

[jcm]

You beat me to it , Billy.

Most stacking programs have a limit to how much "movement" between images they can cope with. They often have a manual mode to get round big differences.

The differences between stars on the above images are so big I don't think any stacking prog. could cope with them.

John

[Psychobilly]

I know one that can ... and does without breaking into a sweat.... not a freebie though....

(click to enlarge)

Registar...

Billy....

[Whippy]

I've done worse in DSS and it didn't break into a sweat either so I'm not sure it's that...

Tony..

[jcm]

I could never get to grips with DSS - perhaps I did not give it long enough.

I use Images Plus which has many stacking options and it works well.

Registar - thought about buying but a bit expensive - $149 - but good if you want to combine images taken with different cameras/scopes etc.

John

[LaVey]

thanks guys... gonna have another go with light frames only in DSS...

My setup is kinda lacking at the mo.. no light pollution filter ... just a 350 strapped to the top of the C6 (have yet to get the t-ring stuff - hopefully this week now hinds is open again tommorow).

might put this down to experience and dump the subs that are way off...