M33

[vincentnm]

Hi All,

Captured this last night with M33 just comng out of the murk.

Scope: C8 hyperstar 3

Mount: EQ6

Camera: SXV M8C

Guiding: ST80 with DFK

Exposure: 3 minutes X 57 subs

Anyone knows what these horizontal lines are. They suddendly started appearing in my subs midway through the session.

Cheers,

Vincent.

[SteveL]

which application are you using to take the images with?

[Aza]

The data you have does look very good.

Not sure about the lines.

For a fix of this data though, Noels Actions may work.

Looks like flats might be a good idea too

EDIT:

Just tried Noels Actions. It fixed the background, but it still had the lines within the galaxy itself.

[vincentnm]

which application are you using to take the images with?

I used Maxim DL 5. Never seen these horizontal lines before. Around 30 initial subs did not have them, and then suddenly started appearing in all subsequent subs

[SteveL]

Have you set Maxim to update the progress bar while actually downloading the image from the camera? I have seen this cause stutter lines in images before (including mine) until I turned that option off.

[vincentnm]

Thanks Steve. Found the setting. Should work next time. Also found instructions at Starlight Xpress Universal

Arran, you are right about the flats. Vignetting is quite visible.

I tried another process with twilight flats. It caused the reverse effect, more dim in the centre than at the sides. Maybe my flats were too strong. Should tried a lower ADU next time.

I tried Noel's actions for horizontal banding, no effect. I guess these lines are too sharp. Pity cant fix this, was decent data except for the streaks.

Thanks,

Vincent.

[SteveL]

I tried another process with twilight flats. It caused the reverse effect, more dim in the centre than at the sides. Maybe my flats were too strong. Should tried a lower ADU next time.

If you are using flats, you need to be using bias/offset frames as well, or you will start to see a dark centre and lighter corners...