M101- Request for help

[Zakalwe]

There about 3.5 hours of subs in here, taken over 3 nights. All on a Equinox80 and un-modified 50D

All related subs/darks/flats were stacked in DSS. Each nights data was placed in it's own group. There was no data in the Main group.

Two questions, if I may:

1) What has cause the weird "dimple" in the image? Was that as a result of using flats with 2 out of the 3 nights (one night's data only has lights and darks)

2) My post-processing skills remain poor....I just do not seem to be able to extract much detail from this. Does anyone fancy having a bash to see what can be extracted?

Thanks in advance

Dropbox file here

[Deneb]

That dimple looks like a bit of dirt/dust, have you checked to see if it appears on your subs.

Nadeem.

[Zakalwe]

That dimple looks like a bit of dirt/dust, have you checked to see if it appears on your subs.

Nadeem.

Yeah, I can't seem to see it in the subs. yet in the flats I can see it as a diffuse "blob"...probably a bit of dust on the sensor. I wonder why stacking the flats didn't remove it?

[Deneb]

well check out what you was using for your flats.

Nadeem.

[themos]

That's too big to be near the sensor, I think. It's probably on the optics and it probably developed some time during the 3 nights, so that some subs are affected and others are not. Stack the 3 nights separately and see when it appears.

[Zakalwe]

That's too big to be near the sensor, I think. It's probably on the optics and it probably developed some time during the 3 nights, so that some subs are affected and others are not. Stack the 3 nights separately and see when it appears.

I thought that by separating the data into different groups in DSS that it would only apply the darks/flats from each night only to that night's subs?

[dmahon]

You're right. Bias/dark/flats are applied in each subgroup only to the lights in each subgroup, then all calibrated lights are stacked together. Great - except when you want to use the same flats for more than one night but not for all nights (for all you can stick them in the main group).

[Zakalwe]

OK, I have gone through the subs and flats:

Night 1- no flats used (only lights and darks)- no "dimple"

Night 2- flats used. No "dimple"

Night 3- flats used. The "dimple" is there. I can see the dust/artefact in the flats <edit> and the subs. I thought that stacking the flats would remove this???

[themos]

There you go, the dimple developed when you were shooting flats.

[Cloudwatcher]

...I just do not seem to be able to extract much detail from this. Does anyone fancy having a bash to see what can be extracted?

Thanks in advance

Dropbox file here

Heres my attempt.............. Given more time there is more detail to be extracted,better seen at full scale...... this has been reduced to fit.

[Zakalwe]

Cloudwatcher...thats pretty impressive. What was your workflow?