Redid data with 8x15min subs better focusing, more tweaking and added coloured version with 4x15min subs of SII and OII, a first for me
Eta done with SW120 mm achro, only basic curves and levels in CS4 as i don't know any more
Taken on 18th Jan 11x10 min 7nm ha baader filter in QHY 2"filter wheel with ST8300M , manual focusing at the start, aligned and combined in ImagesPlus then CS4
Images are old data, new ones
Any hints etc would be most welcome. Thanks for looking.
Marcus
Last edited by Mighty_oz; 26-01-2011 at 07:31 PM.
Reason: forgot the camera details
Looks ok Marcus but the black level is clipped.
Did you do any DDP in images plus to make the histogram better?
Else you have to go for 15 Minute exposures.
Yeah was thinking 15 min might give me more room to manouver with, as was just align and combine, it looked clipped ( to even my inexperienced eyes ) when i did ddp so i left it out.
Looks nice, love Ha images, I didn't realise you could do it with an Achro though.. Is there any real benefit for using an APO over an Achro if only doing Narrow band? Learning new things every day..
Looks nice, love Ha images, I didn't realise you could do it with an Achro though.. Is there any real benefit for using an APO over an Achro if only doing Narrow band? Learning new things every day..
That's interesting. I was thinking then that the benefit of an APO with color correction against a doublet would only really be if you used a filter wheel with parfocal filters? Or use an OSC? If you use a mono that wouldn't matter then as you take and focus each channel separately? Or is there more to it? I know I had (minor) problems with an ED80 doublet with an OSC and blue focusing way out but never shooting Ha which falls in red.
Very nice image. I can see no reason why an Achro shouldn't do as well as an APO with very narrow band Mono imaging as colour correction shouldn't be of any concern.
Marcus, it's amazing what can be done with an achro scope.
And this has come out quite nicely apart from what already has been commented on.
Since you have CS4, go into 'image- adjustments- shadows/ highlights' and see the difference with just the default setting will make. It will bring a whole lot more background detail out and improve the histogram so you're using all the data you have, not just a small portion.
Have a mess with the sliders and see what you can come up with.
Just watch your stars and don't make them look harsh- weird.
Here's a quick example using Shadows/ highlights... gives you lots of control.
Thanks all for the comments, focus was just done once at the beginning, i know i need to do it more often This was just a trail run to see what i could actually get as i'm in very light polluted skies and hence narrowband is the way to go.
Looked at the shadows setting in cs4, sure makes a diff. Thanks for that will play with it, but i'm going to try for better data longer and better focused if i can and at the same time try not to spend a fortune to get it.
Or is there more to it? I know I had (minor) problems with an ED80 doublet with an OSC and blue focusing way out but never shooting Ha which falls in red.
