LBN 558, LDN 1243 & LDN 1251 in Cepheus

[gorann]

LBN and LDN means Lynd's Bright Nebulae and Lynd's Dark Nebulae from his catalogues. These particular ones are quite faint molecular clouds / dark nebulae, about 1,000 light-years away, and they make up part of a complex of dark and bright nebulae in the Cepheus region. The image is based on data I collected about a year ago and now processed using the new Star Xterminator filter in PS to stretch the nebulosity before I brought the starfield back. Interestingly, with a light bucket like the RASA 8 at f/2 many of Lynd's dark nebulae are revealed to be quite bright, lit up by neighboruring stars, except for their darker brownish cores.

Collected with a RASA 8 and ASI2600MC (Gain 100, offset 30. -15°C). 67 x 5 min, so about 5.5 hours. No filter.

Cheers, Göran

Edited November 16, 2021 by gorann

[vineyard]

On my laptop screen that looks 3D, wow.

[gorann]

Thanks a lot! The universe is 4D at least so the aim should be to at least capturing some 3D😊

[GalaxyGael]

That really does have depth. Interesting region and a very nice image. Your dark nebula is brighter than some emission targets 😉. 

 

 

 

 

[gorann]

1 hour ago, GalaxyGael said:

That really does have depth. Interesting region and a very nice image. Your dark nebula is brighter than some emission targets 😉. 

 

 

 

 

Thanks a lot Colm! Dark is in the eyes of the rig! So, with a photon bucket, there is no darkness anymore😉

[The Lazy Astronomer]

I do very much enjoy your images Göran - you always go after such interesting and different targets.

l have a processing question for you (if you don't mind sharing your secrets 😉): what's your technique for bringing forward these very faint nebulous regions and maintaining that nice dark grey background?

[gorann]

Thanks a lot!

There is no special secrets. I mainly use PS (but calibrate and stack in PI) and start by stretching the image in many iterations, at least 7 - 10 times (I attach a typical curve), so the bright parts slowly emerges from the dark sky. I have the idea that many minor stretches preserves the dynamic range better than a few large ones (maybe someone knows if that is true but it works for me). Then after those initial stretches I have recently started using the Star Xterminator filter (in PS but you can also get it for PI). The starless image produced allows me to give the faint nebulosity an extra stretch without being overwhelmed by the star field. Then I bring the stars back using a layer in PS (blend mode lighten) and control the stars size with a curve (takes some trial and error to avoid dark ringed stars).

I hope that helped. There are a lot video tutorials, many of which I believe use similar approaches, that once got me going but it was a long time since I watched one.

CS, Göran

[Stuf1978]

Wow, you really have these dusty images nailed.... great work  

[gorann]

13 hours ago, Stuf1978 said:

Wow, you really have these dusty images nailed.... great work  

Thanks, much appreciated!