alan4908 Posted July 23, 2017 Share Posted July 23, 2017 Looking at CCDNavigator for new imaging targets, I was quite taken by the appearance of SH2-140, which is not often seen within this forum. So, a few button clicks later, I was on my way to gathering an LRGB +Ha image. In terms of the result, which represents 16.5 hours of imaging integration, I went for a Ha blend in both the Lum and Red channels since I thought this would maximise detail and colour. I decided I quite liked the very bright blue stars, so whilst some might think them a distraction from the nebula, I decided to keep them and not to shrink them excessively. Near the "mountain" part of the nebula, I presume this is a reflection nebula created by the bright stars within the emission nebula (?) Comments and criticism welcome. Alan LIGHTS: L:12,R:10,G:6,B:8 x 600s. Ha:21 x 1800s. DARKS:30, FLATS:40, BIAS:100 all at -20C. Imaged with an Esprit 150 on a 10micron GM1000HPS. Link to comment Share on other sites More sharing options...
Dave In Vermont Posted July 23, 2017 Share Posted July 23, 2017 Very nice interplay of light & dark! Thankk you, Dave Link to comment Share on other sites More sharing options...
Rodd Posted July 24, 2017 Share Posted July 24, 2017 That is impressive--the perception of depth is amazing. It really does look like a mountain in the distance. I don't mind bright, big stars, though I would probably want to do something about the blue halos (and I wouldn't be able to). But I notice your star color is not really RGB. Did you add the Ha to the r and L in the stars as well as the rest of the image? Rodd Link to comment Share on other sites More sharing options...
alan4908 Posted July 24, 2017 Author Share Posted July 24, 2017 19 hours ago, Dave In Vermont said: Very nice interplay of light & dark! Thankk you, Dave Thanks for the comment Dave. 1 hour ago, Rodd said: That is impressive--the perception of depth is amazing. It really does look like a mountain in the distance. I don't mind bright, big stars, though I would probably want to do something about the blue halos (and I wouldn't be able to). But I notice your star color is not really RGB. Did you add the Ha to the r and L in the stars as well as the rest of the image? Rodd Thanks Rod - Yes, I also really like the "mountain" part of the image and the way the stars seem to fall onto it. Personally, I think it would have been better if I had rotated my camera 45 degrees so that the mountain was upright ! - Perhaps the crop below is presentation improvement The starfield is actually a mixture (PS Screen blending mode) of RGB with Ha+ RGB with the Ha mixed into the L and R channels. I normally do this to correct any colour imbalance created by the Ha addition. The halo's of the bright blue stars are also in the stretched RGB image, again I could have eliminated these but to me that wouldn't have looked natural. Alan Link to comment Share on other sites More sharing options...
Rodd Posted July 24, 2017 Share Posted July 24, 2017 8 minutes ago, alan4908 said: Thanks for the comment Dave. Thanks Rod - Yes, I also really like the "mountain" part of the image and the way the stars seem to fall onto it. Personally, I think it would have been better if I had rotated my camera 45 degrees so that the mountain was upright ! - Perhaps the crop below is presentation improvement The starfield is actually a mixture (PS Screen blending mode) of RGB with Ha+ RGB with the Ha mixed into the L and R channels. I normally do this to correct any colour imbalance created by the Ha addition. The halo's of the bright blue stars are also in the stretched RGB image, again I could have eliminated these but to me that wouldn't have looked natural. Alan But did you include the Ha addition in the stellar cores? I am thinking that straight RGB cores may have more color Rodd Link to comment Share on other sites More sharing options...
alan4908 Posted July 24, 2017 Author Share Posted July 24, 2017 3 minutes ago, Rodd said: But did you include the Ha addition in the stellar cores? I am thinking that straight RGB cores may have more color Rodd Hi Rodd - yes, the Ha addition is in the steller cores but not in the background. The Ha was also black clipped before PS Screening into the RGB to avoid a colour cast across the background. To guarantee smaller halos and more colour in steller cores then I've found that all you need to do is to ensure that the Lum values are below 200 in PS prior to blending the colour layer. However, this can create an unnatural look since it obviously dims very bright stars relative to their neighbours. Alan Link to comment Share on other sites More sharing options...
ollypenrice Posted July 25, 2017 Share Posted July 25, 2017 Great to see something new! This is a fine result. Olly Link to comment Share on other sites More sharing options...
alan4908 Posted July 25, 2017 Author Share Posted July 25, 2017 41 minutes ago, ollypenrice said: Great to see something new! This is a fine result. Olly Thanks Olly Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.