First Light - Atik 314L Mono - Eagle Nebula

[DJScotty (Scott)]

Hi all,

looking for some constructive criticism for acquiring and processing narrowband images.

This is my very first foray into this branch.

Attached is a Ha and OIII processed in PSCS6.

10 minute subs, about 3 hours of each, taken on the Atik 314L Monochrome camera cooled to 0 degrees
No darks or anything like that
Image acquisition done through Nebulosity trial version, hence the dark lines
Guided with PHD
8" f5 newtonian on HEQ5 Pro (1000mm)

Given all the things that are wrong with the image which can be improved with more data, how can I improve this ?

Thanks everyone.

[LewisM]

I'd be having that Atik checked over by Atik or theirapproved technicians - that seems to be a LOT of read/output eror in that image. No amount of extra data will fix that.

It COULD be a stacking error, but it looks very much more like a progressive readout error, either in the camera, or the USB connection or...

Are the diagonal lines present in each individual sub frame?

[alocky (Andrew lockwood)]

Is there any reason the camera is running at 0 degrees? That's not actually very cold. Why not run it as cold as it can go and check the noise again?
Cheers,
Andrew.

[DJScotty (Scott)]

Hi Lewis,

the lines are there because I have not yet purchased Nebulosity. It places the lines on the image until you enter a registration key. Still trying to decide whether or not I want to fork out $80 for it.

Or are you referring to the wiggly blue lines in the image attached?

Andrew, I just chose that temperature arbitrarily. I will push the temp down further tonight. Maybe try -10 degrees...

Thanks for your speedy reply gentlemen...

[Merlin66 (Ken)]

I regularly use the ATiK314L for spectroscopy.
Push the temperature down as low as you can go...(-25 below ambient...)
take some darks....
I generally do my darks/ lights at -10deg.
Using and recommend AstroArtV5

[gregbradley]

A great start. You have some guiding problems as the stars are elongated.

Make sure:

1. The Polar Alignment of the mount is as accurate as possible.
2. Your mount is well balanced.
3. No cable drag is occuring.
4. Try shorter exposures if needed to get round stars.

If you are using a guide scope make sure everything is tight and no slop or wiggle.

Greg.

[LewisM]

Ah, Nebulosity's "Can't save till you buy" protection. Got you.

Do as mentioned - go cold, with lots of darks

[DJScotty (Scott)]

Everyone,

thanks very much for your help and advice.

Weather in Brisbane is absolutely perfect at the moment. Will try all of your suggestions tonight.

Once again, your help is greatly appreciated!

[DJScotty (Scott)]

Actually, while I think about it, Ken, you suggested Astroart. Does it "talk" to PHD Guiding to enable dithering? If not, are there any other programs that have that capability?

[Screwdriverone (Chris)]

Nice Start Scott

As for the wiggly line, it is a dead or hot pixel that is stacked and due to any polar alignment errors between subs, will "track" like you see there if you dont have darks to remove them.

Trust me, I see them ALL the time in my images stacked in Nebulosity if I don't make a bad pixel map.

I have quite a few on my Atik 314L+ and even half a bad column which both completely disappear with calibration frames.

Alternatively, use Deep Sky Stacker which seems to do a better and easier job of stacking and de-rotating for bad alignment or guiding as well as eliminating these pixel tracks across your image.

Before you get upset by the camera having a dead or hot pixel, it is pretty normal on this sensor, I noticed some on mine pretty much out of the box when new.

Hope this helps

Cheers

Chris

[DJScotty (Scott)]

Alright everyone,

I have to say once again thanks for all of your helpful advice.

Put everything in place and now see the results.

34 x 5minute subs
Cooled to -15 degrees
Only 2 darks (am acquiring them as we speak)

Also, I bit the bullet and purchased Nebulosity, so bye bye dark lines.

Overall a drastic improvement

So once again

[Andy01 (Andy)]

+1 Nebulosity and it will dither with PHD.

[DJScotty (Scott)]

Hi everyone,

As I said in my previous post I am acquiring the darks at the moment. I just noticed that the temp of the darks is hovering at about -8. The lights were -15.

How critical is it that the darks and lights temp matches exactly? Is a 7 degree difference going to have earth shattering consequences?

Thanks for your help