Another go at NGC 6946

[Sam]

I added some data to NGC 6946 last night and managed to push the guiding out to 7 minutes - had to do some emergency soldering though :x . The emergency soldering meant I got started an hour later than intended which resulted in the bottom of the telescope hitting the tripod legs sooner than I anticipated - luckily though that was coinciding with the moon getting higher and illuminating some high cloud.

So here it is with last night's data and the data from last, I'm hoping to get about another hour (might even go to ten minute subs!!):

2 X 7mins

17 X 5mins

1hr 39mins total, canon 400D through an Orion XT8, autoguided by a SPC900NC(SC1 modded) on a ST80.

(click to enlarge)

Sam

[Tim]

Wow! It's really coming on Sam, that's great!

I notice you have those same drag marks though that I got recently, do you have any idea what causes them? It's SOMETHING in the stacking, but I'm not sure what, RGB Aligning maybe?????? Did you check the option to RGB align in final image in DSS?

Great pic anyway, really good.

TJ

[Sam]

Thanks TJ, I don't know what is causing those but it took ages to try and get rid of them. I have only got them when I use offset frames - which I did for this one, so I must be taking the offsets wrong. Any ideas?

[Roy Batty]

It has definately benefited from the extra data, not an easy subject with the moon affecting any galaxy targets.

RB

[steppenwolf]

This is a very attractive image indeed - well done.

[centroid]

Building up to be a very nice image Sam.

Dave

[narrowbandpaul]

could it be fixed pattern noise from the sensor itself. I noticed FPN on my Canon 300D. It can be removed by subtraction (using dark frames, and bias frames). Did u add the frames or average them. A median combine may work better if your frames are slightly offset.

Best Wishes

Paul

[Sam]

I've managed to narrow it down to two subs I took last week when the moon was out. For some reason they ended up with the diagonal pattern when DSS had to rotate them a little and this came out during processing. Paul, I don't think it's noise from the camera as all of the other frames were fine.

Sam

[narrowbandpaul]

problem solved then