The Horsehead Nebula - Curtain and puffy bits

[batema (Mark)]

Hi,

Based on the advice of my previous post I have added more hydrogen alpha data to my image. This image consists of 8 hours of Luminance data blended with 13 hours and 20 minutes of Hydrogen Alpha at a blending of 36% Ha to 64% Luminance to form the luminance layer for the combining with 2 hours and 30 minutes of Red and Green data with 3 hours of Blue data. The total amount of data is 29 hours 20 minutes.

I HAVE AN ALIGNMENT PROBLEM I realigned all images in Deep Sky Stacker using a reference frame which I always use and my Orion Nebula shows all stars nicely aligned. However this image adds hydrogen alpha and I get star alignment issues????? I do not know why so any advice on this would be greatly appreciated. I have changed nothing from Orion to this so am at a loss. I am pretty happy with the cutain and puffy bits.

Link to my high resolution so you can see the disgusting stars here: https://www.flickr.com/photos/134809.../in/datetaken/

Imaging Scope: TEC 140mm with flattener
Mount: Astrophysics1100
Camera: SBIG STT 8300m with Self Guiding Filter Wheel

[multiweb (Marc)]

Looks pretty good to me Mark. Great colours and details.

[RickS (Rick)]

Advice well implemented, Mark!

[Rod771 (Rod)]

Very Good, Mark! Nicely done!

[Peter Ward]

Do you re-focus with each filter?

In any event the Focal Length is ever so slightly different with many refractors from the Blue to red ends of the spectrum. (AP 'sopes seem to be immune )

The fix is to re-scale each channel so they are the same size/FL....then do your colour add.

[batema (Mark)]

Thankyou all for the comments. Peter I use the SBIG STT8300 and I do not refocus for each filter. Maybe I should but all images prior to this one seem to align perfecly. Could you tell me how do I rescale the images if that is easy to explain. I really don't understand why they aren't aligning.

[rustigsmed (Russell)]

that's a very nice HH mark, I would be stoked with that the colour the curtains etc look great. the blending seems to have worked a treat too, did you consider also adding some of the Ha to the red channel?
Maybe you could try RegiStar to work the alignment woes out?

cheers

[Atmos (Colin)]

Originally Posted by batema

Thankyou all for the comments. Peter I use the SBIG STT8300 and I do not refocus for each filter. Maybe I should but all images prior to this one seem to align perfecly. Could you tell me how do I rescale the images if that is easy to explain. I really don't understand why they aren't aligning.

I believe it is either running a Deconvolution or covolution on the individual channels depending on whether they need to be made smaller or larger.

[gregbradley]

Looking very nice Mark.

I find occasionally Ha will not register well with LRGB images using CCDstack.

Luckily though there are several registration methods with CCDStack and I pick one of the others until one works. Usually its the one that rotates, scales and magnifies as needed.

You should start using CCDstack as deepskystacker is more for DSLRs I thought.

Greg.

[batema (Mark)]

Thank you again for the suggestions. I will look into it Greg.

Mark

[gregbradley]

Originally Posted by batema

Thank you again for the suggestions. I will look into it Greg.

Mark

Its also the lack of stars in Ha images that throws it. If the Ha master is too far away or reversed compared to the LRGB it may not register easily. In that case I manually reverse it (in CCDstack this is easy) and sometimes I manually move it so its quite close. Then the automated registration usually works. If not I use rotate, scale and magnify to get it to register.

If still no go there is always PixInsight which seems to be a bit more robust.

Greg.

[batema (Mark)]

Thank you Greg. Downloaded the trial version of CCD Stack and will buy it.

[batema (Mark)]

I have looked at each master frame after deep sky and they did not line up as normal. I do set up and pack down eack night but leave my tripod in place. At 44 degrees during the day I have to do this. Maybe that's why. I have looked at tutorials on ccd stack and will have a go at that.

[Shiraz (Ray)]

very nice image Mark - plenty of structure and the colour is great

[astronobob (Bob)]

Wowsers Mark, that is a total Stunner - Love them colours also ! !