Sharpless 115 is a very large emission nebula in the constellation of Cygnus the Swan, about as far west of Deneb as the North American Nebula is east of it. It is thought to be about 7,500 light years distant and contain enough gas to make 4400 stars the size of our sun. It covers several times the area of sky that I can fit into my field of view. The nebula likely formed the star cluster Berkeley 90 toward the upper left of center in my image. The illuminating star, the one whose ultraviolet light causes the hydrogen gas to glow, is a member of the cluster and one of the brightest and most massive stars known. It is classed as 06. Find the cluster and note there are two brighter stars diagonally across opposite sides of the cluster from 7 O'clock to 1 O'clock. The one at 7 O'clock is the illuminating star. It is known as LS III +46 12. It appears dim compared to other stars in my image because most of its light is emitted as ultra violet light. That is mostly blocked by our atmosphere and what little does get through is blocked by my filters since it is outside the visual range of our eyes. The nebula itself is about 100 light years across. For a star to light up gas 50 light years from it is quite a feat and shows how bright it really is! But for that it will pay dearly. It will live only a couple million years before going supernova while our sun with less than 1/10th the mass will live over 10 billion years.

I've processed this for high contrast. Doing so caused much of theSharpless 115 is a very large emission nebula in the constellation of Cygnus the Swan, about as far west of Deneb as the North American Nebula is east of it. It is thought to be about 7,500 light-years distant and contains enough gas to make 4400 stars the size of our sun. It covers several times the area of sky that I can fit into my field of view. The nebula likely formed the star cluster Berkeley 90 toward the upper left of center in my image. The illuminating star, the one whose ultraviolet light causes the hydrogen gas to glow, is a member of the cluster and one of the brightest and most massive stars known. It is classed as 06. Find the cluster and note there are two brighter stars diagonally across opposite sides of the cluster from 7 O'clock to 1 O'clock. The one at 7 O'clock is the illuminating star. It is known as LS III +46 12. It appears dim compared to other stars in my image because most of its light is emitted as ultraviolet light. That is mostly blocked by our atmosphere and what little does get through is blocked by my filters since it is outside the visual range of our eyes. The nebula itself is about 100 light-years across. For a star to light up gas 50 light years from it is quite a feat and shows how bright it really is! But for that, it will pay dearly. It will live only a couple million years before going supernova while our sun with less than 1/10th the mass will live over 10 billion years.

I've processed this for high contrast. Doing so caused much of the faint nebulosity to be lost. The entire field shows nebulosity in the raw data but if I processed it for that then most of the detail would be lost. Computer monitors can reproduce only 255 brightness levels plus black while the original data has about 4000 different levels. This means I have to pick and choose what to show you and what to leave out or allow to get lost due to low contrast. Just one of many decisions I have to make when processing these images. This is why you will rarely see two images of the same object that look the same. Each imager has to decide what compromises best show the object the way the imager want's it shown.

Processing was made even more difficult because the color data was taken on a much colder night than the L and Ha data. That meant it was taken at a different image scale. Then the Blue was taken several hours after Red and Green during which time the temperature fell even further again changing the image scale. Thank goodness for Registar. It corrected for all this and more.

In the upper left, left of two bright blue stars and in a small hole in the nebulosity between two somewhat bright stars is the open cluster Berkeley 90. Most of its stars appear rather red and faint.

14" LX200R @ f/10, L=3x10+HA3x30', R=2x10'x3+HA3x30'*80%, G=2x10'x3, B=2x10'x3+HA3x30'*20%, HA blended using lighten mode in all cases, STL-11000XM, Paramount ME faint nebulosity to be lost. The entire field shows nebulosity in the raw data but if I processed it for that then most of the detail would be lost. Computer monitors can reproduce only 255 brightness levels plus black while the original data has about 4000 different levels. This means I have to pick and choose what to show you and what to leave out or allow to get lost due to low contrast. Just one of many decisions I have to make when processing these images. This is why you will rarely see two images of the same object that look the same. Each imager has to decide what compromises best show the object the way the imager want's it shown.

14" LX200R @ f/10, L=3x10+HA3x30', R=2x10'x3+HA3x30'*80%, G=2x10'x3, B=2x10'x3+HA3x30'*20%, HA blended using lighten mode in all cases, STL-11000XM, Paramount ME

Processing was made even more difficult because the color data was taken on a much colder night than the L and Ha data. That meant it was taken at a different image scale. Then the Blue was taken several hours after Red and Green during which time the temperature fell even further again changing the image scale. Thank goodness for Registar. It corrected for all this and more.

In the upper left, left of two bright blue stars and in a small hole in the nebulosity between two somewhat bright stars is the open cluster Berkeley 90. Most of its stars appear rather red and faint.