NGC6914

[don4l]

During the summer I took a few shots around Cygnus.  They all look a little bit "red".  In fact, they almost looked like a tinted monochrome image.  This afternoon I looked for some other colours, and I found this.  The blue bit at the top is called NGC6914.  I've had a go at giving a bit of colour to the stars.  Any advice would be appreciated.

Sadr is just to the right of the middle, and Deneb is a bit further off to the left.  As far as I can see, nothing else has a name.

 

This is 70m Ha, 21m Green and 18m blue (Total 109m).  It was taken on the night of the 7th July.  It was taken as just a bit of practice for mosaic construction.

Calibrated in CCDStack, and tweaked (including false flats) in Picture Window Pro.

 

 

[wimvb]

Nice image. Did you use Ha for red? That would explain the colour. The sadr region of Cygnus is full of Ha clouds.

[don4l]

2 hours ago, wimvb said:

Nice image. Did you use Ha for red? That would explain the colour. The sadr region of Cygnus is full of Ha clouds.

Thanks.

Yes, it is a Ha, G, B image.  I didn't use the red filter at all.

The colour is much better than my previous attempts, which were a pasty brownish-red.

 

[edit]  I realise that you were referring to my "red" comment.  What I meant was that I had processed them without giving any thought to the green and blue.  It was only when I put a few images together in a mosaic that I realised that something was missing.  I reprocessed the above today, and  now, in my eyes, it looks quite OK.  I now have to look at the rest of the set and see what I can do.

[john2y]

Nice image, I noticed that some of the stars have some weird halo around them, did you capture it like this or did this show up during processing?

[don4l]

58 minutes ago, john2y said:

Nice image, I noticed that some of the stars have some weird halo around them, did you capture it like this or did this show up during processing?

The halos are due to reflections on my Astronomik Ha filter. Light bounces off the CCD surface, and is reflected back by the filter.  They are there in the individual subs.  I usually try to reduce them during processing, but I forgot this time.

My filters date from 2007.  I believe that they fixed the problem a year or two later.

I recently got a Chroma Ha filter, and it doesn't have the problem at all.  I'll be also replacing my SII and OIII filters soon.

[john2y]

12 minutes ago, don4l said:

The halos are due to reflections on my Astronomik Ha filter. Light bounces off the CCD surface, and is reflected back by the filter.  They are there in the individual subs.  I usually try to reduce them during processing, but I forgot this time.

My filters date from 2007.  I believe that they fixed the problem a year or two later.

I recently got a Chroma Ha filter, and it doesn't have the problem at all.  I'll be also replacing my SII and OIII filters soon.

Ahh makes sense, it didn't occur to me since I'm in astrophotography just couple of years and only filters that make reflections I know are Oiiis.