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Dom543

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Everything posted by Dom543

  1. Rob, From here everything will be only easier. Martin uses a filter wheel with his Newtonian and a photo of his setup is on the last post of the first age of this same thread. I use a manual filter drawer from TS that requires only 15mm back focus. If you attach a T-threaded 1.25mm eyepiece holder (also available from TS) on the camera side, then you can push the Lodestar very close to the filter. I am sure that you will be able to reach focus. Good luck! --Dom
  2. Rob, Thank you, you are right. In my particular case, I had three telephoto lenses on a cross bar aiming at the same object and I was also swapping three filters between the three cameras in the dark. So there were many things to pay attention to at the same time. Initially I tried to use the same file names for the same objects. Then later, as you see on the posted images, I did prefix each file name with the respective sensor's ICX number. I am not very good at paying attention to different things at the same time and I thought that it would have been nice to have some obvious visual cue to distinguish the windows. Even just different colored text in the title bar would have been sufficient. But this may not be a typical case. I don't know how many people use several cameras at the same time. Even, if there is just one new night light skin, I could use that with one of the cameras and the old day time skin with my AstroRed windows theme for the other. Three cameras is probably more than what I would want to manage simultaneously with the short ~1 minute exposure times anyway. Clear Skies! --Dom
  3. We were taught that kids, who wish fewer gifts from Santa receive more. But since Paul himself said that he is working on night mode skins, I wish that there were at least two different such skins. Or one of their components could be user selectable. The other night I was running three separate versions of StarlightLive simultanously with three different cameras. It would have been nice to have some visual cue to indicate which camera's window I saw in the foreground. Even just a colored dot in the title bar would be sufficient. Anything simpler than going to the Exposure tab and trying to remember which camera corresponds to PID 0189. Thanks, --Dom
  4. Western and Central Veil Triple NB, no binning This is again a capture made at the full 6Mp resolution of the SX-964, but to fit posting file size, the image has beed reduced to 50% (linearly). The resolution of the reduced image is 1.5Mp, about the same as full resolution with the Ultrastar/SX-825/Infinity. 2x90sec exposures per channel mean stacked. Red is H-alpha, green is S-II and blue is O-III. I use the Baader 6 (Ha) and 8.5 (O-III and S-II) nanometer NB filter set. The same Nikkor 400mm f/2.8 ED teleobjective was used as optics. This Western part of the Veil has extensive Sulphur coverage but the S-II signal is much weaker than in the Eastern part. More spread out but weaker. I tried to stack 60 sec exposures and it went well for the O-III and H-alpha. But when the S-II was added, the entire image got very noisy. Since Sulfur is all over, noise was also all over. Then I switched to 90 sec exposures and got what you see. If signal is weak, then there is a floor on exposure times, one cannot go below that. For comparison, here is a capture of the same area with the SX-825/Ultraster Sr made last summer https://stargazerslounge.com/topic/269747-multispectral-captures-with-lodestar-and-ultrastar-mono-cameras/?do=findComment&comment=3036938. It uses a different palette but al;so 90 sec exposures. On these web postings there doesn't appear to be much difference between the full resolution Ultrastar image and the 50% reduced 694 image. Comparing them on a 32" Ultra HD 4K monitor, the two are clearly in different categories. The best I can do here again is to cut out an area from the full resolution image that still fits within the posting file size. Here it is. To see any of these images in their highest possible posted resolution, you have to click on the image and than click the "Full Size" button in the lower left corner. Clear Skies! --Dom
  5. Thanks Paul, I agree that there is still a lot of fun, and more fun, ahead for us in EAA. But when we are enjoying the rosy outlook ahead, we should also remember that the recent EAA revolution, that lead to the current live software supported use of still USB cameras, has been the result of two key developments. One was Nytecam's discovery of the potential of the Lodestar and the other was your development of LodestarLive. To answer your question, I didn't notice any processing time bottleneck. I use a very old and outdated laptop. I keep it because it has a very nice large and fine resolution screen that they don't make any longer. But its processor is geriatric so my processing times would not be relevance to anybody using current generation computers. But even so, there is no stacking backup or anything that would interfere with enjoying the views. Download times are noticable longer with the 6Mp sensor. But that's due to USB2 bandwidth. Nothing we can do about. For alignment and focusing with short 1 second exposures I use 2x2 binning. Thanks again for all the effors that you have put into StarlighLive. This time I particularly appreciated the fact that the software is absolutely future proof, keeps the door to upgrading cameras wide open. --Dom
  6. Eastern Veil Triple NB with SX-694 and no binning Here red is Hydrogen, green is Sulfur and blue is Oxygen. Yellow is the mix of Ha and Sii. Magenta is the mix of Ha and Oiii. This is at the full resolution of the camera but I had to reduce the capture to 50% to fit the posting file size limits. At this reduced size the pixel count is about the same as that of the Ultrastar/SX-825. Even to see the image at this reduced resolution, you will probably have to click on what you see on the web page. These are 3x60sec exposures mean stacked with each of the three filters. I was totally surprised that I got this image with just 60sec exposures. I could have obviously gotten more detail and smoother texture by stacking more frames. But I use a rather stict definition of "near real-time" when it comes to my own work. (Don't worry, I am more tolerant to others.) The optics used was an old manual focus Nikkor 400mm f/2.8 teleobjective. I aimed at the Veil because it has both colors and fine detail. And also, because earlier this summer I spent some time exploring the potential of the Veil using the SX-825. This post has two captures from that venture for comparison https://stargazerslounge.com/topic/269747-multispectral-captures-with-lodestar-and-ultrastar-mono-cameras/?do=findComment&comment=3036103. The screen appearance of the captures with the 825 and the 694 are quite similar on these internet postings. Due to the fact that both are reduced to the same size and to similar pixel counts. The lesson is, if the sole purpose is to post on these forums, then there is no point in using a higher resolution camera. To show a close-up of the texture and detail at full resolution, I cropped out a part the original unreduced image that fits the file size limit. I believe that this is the part called NGC6995. Again, you will have to click on what you see to get the full resolution image. This is a stack of three 60sec frames per channel and no binning. Clear Skies! --Dom
  7. I saw a used SX-694 monochrome Trius on Astromart for an affordable price. I bought it as a reward and compensation for all the work that has been keeping me away from astronomy in the past year. The logic: If you don't have time for astronomy, have at least a new camera. Makes complete sense, doesn't it? Given the limited time I can spend under the stars, I wanted a camera that I could use immediately. Without a long learning curve, without waiting for adapters from Precision Parts, without waiting for software to be written etc. I wanted a camera that I could use for near-real time EAA today and that would also have potential for something over my existing cameras (SX-825 and Lodestars). The SX-694 fit the parameters, as it has the exact form factor of the SX-825 and thanks to StarlightLive being vertically universal for all SX cameras. The SX-694 has a 6Mp (2750 x 2200) 16mm diagonal ("1 inch format") Exview CCD sensor with 4.54 micron square pixels. For comparison, the SX-825/Ultrastar has 1.5Mp (1392 x 1040) 11mm diagonal (2/3" format) sensor with 6.45 micron pixels. The Lodestar has a 0.44Mp (752 x 582) 8mm diagonal (1/2" format) sensor with 8.2x8.4 micron pixels. More detailed specifications of the camera can be found here https://www.sxccd.com/trius-sx694 or even more detailed here http://www.highpointscientific.com/telescope-accessories/astro-photography/ccd-cameras/starlight-xpress-trius-sx-694-mono-ccd-camera-usb-hub. My calculation was that, if I bin the SX-694 2x2, then I should get Lodestar sensitivity (9 micron pixels) and Ultrastar/SX-825 resolution (1.5Mp). Those combined would satisfy my requirement for "something over my existing cameras". What follows below is a "first light" thread and first light is about looking for fun. Not about writing an evaluation for scientific publications. To me real fun must involve colors. And as the 694 is a higher resolution camera, looking for details is also essential part of a first light fun. Let the action begin. The mailman with the Priority mail box pulled up, while I was loading my van for an astro outing. It was urgent to leave to get through traffic and to set up before dark. The computer was already in the van so I didn't have time to download any drivers. I just threw the box in the van and hit the road. The plan was to screw the new camera in the place of the SX-825, connect the same cables and see what happens. What happened was the best of all possible scenarios. StarlightLive opened, connected to the camera and recognized it. The only thing it failed do was congratulating me to my new camera. That will be my new feature request for v.3.3. I see that there is already a thread for that. Clear Skies! --Dom
  8. Can someone please explain me what FWHM, Mean FWHM and Max FWHM mean and do? Thanks, --Dom
  9. Hi Rob, If you already have a stack and want to see what the individual color channels contain, then go to the Channel Selection" area on the Display Processing tab and check the rightmost "Display Selected" checkbox. Then only the contents of the one channel will be displayed, whose radio button is checked in the second row of the "Channel Selection" area. It will be displayed in monochrome B&W. This feature can also be used to see what you are currently adding to an already existing stack, provided you are allocating the current capture to a single channel. (This trick is complementary to what Brandon said and for a different situation.) The ultimate best triple channel NB target for this time of the year is M1, the Crab ( see my avatar also made with a LSx2m). Clear Skies! --Dom
  10. Hi Martin, Very interesting study ! Since we are all on new territory here, I am spelling out aloud here what and how I am thinking. Stars are the brightest objects in astronomy, so we are dealing here at the bright end of the tone scale. (I entirely ignore the faint end of the scale for the purpose of this post.) Non-linear options re-map the brightest tones to fainter ones. They do this to reduce blowout and to enable the user to increase overall brightness without excessive blowout. In other words, applying a non-linear tone map is only one step in the process towards getting a more pleasing image. It is not the only or the final step. It dims down certain elements of the image to make it possible to increase brightness, through increased exposure time, without getting too large areas to reach maximum saturation. In light of this, your captures displayed with the non-linear options have accomplished the first step. The brightness of the brightest elements of the images, which are the stars, have been reduced. But as I see it, the purpose of this is to enable longer exposures. And hence more bit depth and color depth. In line with this thinking, I believe that the image that would be a fair comparison to the linear option would be not one that is merely dimmed down by the use of one of the non-linear tone maps. But one, that has then be brightened back up to the same level as the liner map, by an extended exposure. This is how I see it. I would be curious to hear your and others' opinion on this. Unfortunately, I will be travelling in the next couple of days and will probably not be able to log in to the forums. Clear Skies! --Dom
  11. Jim, If you have saved the FIT files, you can reload them with the "<path>\StarlightLive.exe - args -load-image-rggb <path>\<filename>.fit" command line. And try out the non-linear options on them during daytime. It takes a bit of experimenting to get used to the non-linear settings. It's better done during daytime than wasting precious time under the night sky. Martin, I believe that in AP, people essentially take and process separate images of nebulae and of the surrounding stars. Then they merge the two layers in the last step. I have seen many images that they call Ha-RGB or NB-RGB. The RGB is the get white, or naturally colored, stars. I am also adding some times very short extra frames to my NB multi-spectral captures to make stars white. E.g. this is how I got a white Sagittarius Star Cloud in front of the red H-alpha nebulosity. Since stars are so much brighter, a 5 second frame is often sufficient to straighten out their colors. And the 5 seconds do not affect at all the nebula, that may have been captures with 60sec exposures. Clear Skies! --Dom
  12. Jim, You are getting very nice star colors ! Try to use the arsinh option. That helps to prevent, or at least delay, saturation and allow longer exposures. Fully saturated pixels are white, no matter what. That kills the nice subtle yellowish hues. When you switch over to arsinh, you may see an almost entirely white screen and no histogram. The contrast slider needs to be pushed down to very close to zero for a nicely shaped histogram to reappear. Then the black level slider needs to be placed just below the histogram to make the background dark. One can also try the x^0.25 option. But in my experience this results in more washed out stars that look as if they were out of focus. Clear Skies! --Dom
  13. Brandon, The camera is at the straight end of the flip mirror. So the mirror is flipped out of the way and has no effect when the light is directed to the camera. I use the flip mirror on a daily basis with my SCT's, this is my diagonal. I always use it to align the mount. All my posted captures that use an SCT and don't use the 3.3x reducer are through this flip mirror. It is also very convenient for making darks. One can even make darks, while one is centering the object in the eyepiece. Clear Skies! --Dom
  14. Eric, If you don't find any such cells and are still interested, drop me a PM in December. Years ago, when I saw them, I bought a couple and had a few spares left. I sent one to MagnaMan in 2014 and I probably still have one somewhere that I could send you. The only problem is that I work at various places around the country and right now I am 3000 miles away from home. I should be back home around December 10 or so. BTW the Vixen flip mirror has an odd M49 thread in its nosepiece. Not the M48 commonly used for 2" filters and other astro accessories. So I needed to add a few set screws to keep the M48 cell firm and straight in there. Clear Skies! --Dom
  15. Hi Eric, Thank you for digging up the old thread about the flip mirror. Since then I have switched to using a Lodestar, that has a larger sensor than what the LN300 had. Correspondingly, I also modified my setup and reduction factor. I still have the same flip mirror with the Meade 0.63x reducer but on the camera I now have only a 0.7x reducer. This change was needed due to the larger 9mm diameter sensor of the Lodestar. (As opposed to the 6mm diameter sensor of the LN300.) The original more aggressive setup would strongly vignette the larger sensor and also cause ugly distortions in the outer regions of the field. I am not sure, if the 120mm achro could be focal reduced down to f/2.5-f/3. Chromatic aberration of refracting optics is getting worse with more bending of the light. And f/2.5-f/3 requires a LOT of bending. Also, you needed to cut a LOT from all tubes. A 120mm f/2.5 refractor is about 1 foot long. I am not saying that it is not possible to achieve focal ratios below f/3 with refractors. But I am not sure if an ad hoc home made three stage optics would achieve satisfactory optical quality. I do have a 300mm focal length f/2.8 Nikkor camera lens that works very well. But this lens contains ED glass element and photo equipment guru Ken Rockwell lists it among the "10 best lenses Nikon has ever made". We are not the Nikon optics design team here... If you are hungry for fast optics, then, rather than starting to cut your OTA, I would recommend to consider used manual focus camera lenses. They are very affordable up to 300 mm focal length. This is exactly what your 120mm achro would yield at f/2.5. I recommend to look at the Pentax M42 scew mount lenses. They are very easy to adapt to astro use requiring only a thread adapter. I have a 300mm f/4 Asahi Takumar lens and I believe that I paid less then $100 for it. (Asahi Optics later renamed itself to Pentax.) In summary, while my flip mirror focal reducer works well with SCT's, I wouldn't recommend to cannibalize a nice refractor to work with it. A lot needed to be cut from the tube and the resulting optics would probably have lots of aberrations. Clear Skies! --Dom P.s. By the way, the spacing between the two reducers is about 100mm in my setup.
  16. Thank you Paul! Thanks to your continued efforts, StarlightLive has been the model for near real-time astronomy applications. Other software makers follow your leadership and users of their cameras envy the features and ease of use of StarlightLive. One of the very useful new features is to run multiple instances of StalightLive simultaneously on the same computer, each connected to a different camera. Since I am a very poor typist, especially in the dark, I made Windows shortcuts for each of my cameras to launch StarlightLive and connect to one or the other specific camera. For those, who want to use this feature, here are the command lines for three most commonly used cameras. Lodestar: <path>\StarlightLive.exe -exclusive-sx-pid 0x0507 Ultrastar: <path>\StarlightLive.exe -exclusive-sx-pid 0x0505 SX-825: <path>\StarlightLive.exe -exclusive-sx-pid 0x0189 When using multiple cameras simultaneously, the cameras have to be different models. As far as I know, mono and color versions of the same type of camera have the same product ID's and hence cannot be launched simultaneously using this method. Clear Skies! --Dom
  17. Hi Jim, Very interesting and useful study. You are doing a great service to the EAA community. I just have one minor comment, or rather question. Does StarlightLive indeed run on the scaled-down iOS? Or does it require the full-fledged MacOS? I am not an Apple user but I thought that imaging applications would not run on iPhones and other iOS devices. Based on the images included in your study, and the ones posted by Martin, it seems clear that the Infinity applies a software smoothing. This makes its unstacked images look smoother and this is why the quality of their captures don't seem to improve proportionally with stacking. Whether to apply or not to apply smoothing is a design decision. And, in a sense, a design compromise. In contrary to stacking, smoothing in software doesn't improve the data on which the images are based. It alters the data by putting it through a low-pass filter. This cuts out changes on the fine scale that may be noise but may just as well be be fine detail. Smoothing, sometimes also called "noise reduction", produces a smoother looking image at the cost of losing fine detail. This is the reason why the double stars are not split on the Infinity image in Martin's post and this is probably also part of the reason, why Atik made sure that the Infinity software cannot be used with their astrophotograpy cameras. They wanted to make sure that people are not using the Infinity software to collect data meant for post-processing. Astrophotographers need to be in full control of what details they want to retain and what they are willing to discard. Thanks again for the interesting and useful comparison study. Clear Skies! --Dom
  18. Hi Rob, It is very interesting what you are doing. I would also be interested to be able to have some plate solving done during my real time observing sessions. The other night I spent over a precious hour of aimlessly looking around in the Southern Cygnus - Vulpecula - Sagitta area without finding my orientation. Next day, when I got to the internet and checked with Astrometry.net, it turned out that I mistook the double star Alpha-Vulpeculae for Albireo and that threw me off. Late at night and in the cold brain just doesn't work that well... If I download Astrotorilla, will that also include the Astrometrics server and data files? And does Astrotortilla work on Windows computers? This far the only option to use Astrometrics without an internet connection was to recompile and/or reassemble the entire package on my computer. And I believe that it was only for Linux and Mac-OS. Anyway, keep us informed of your efforts. It would be nice to be able to connect Astrotortilla to StarlightLive. But even if it works only with APT, it's better than wasting time on not knowing what we are looking at. If I remember it correctly, APT is ridiculously inexpensive. Clear Skies! --Dom
  19. Cocoon Nebula For a change from the many wide field Hubble palettte Veil captures, here is the little Cocoon IC 5146 (Caldwell 19) in its natural colors and taken with a Lodestar mono camera. It is a favorite SCT H-alpha target but it is quite challenging to also get its blue reflection component. Much more difficult than M20. The unsharp appearance of the stars that are imbedded in the nebula is, actually, an effect of the scattering of their light by the reflecting dust. 3x45sec H-alpha (red) + 3x45sec blue + 1x2sec luminance exposures mean stacked in StarlightLive. The short exposure with the luminance filter was assigned to the green channel only to make stars white (rather than purple). Meade 10" SCT was used at f/4.0. The capture was taken from the Wenas wild life area East of Seattle still in May. On the same weekend as the first images of this thread. It somehow never got posted. Clear Skies! --Dom Looking at the post a day alter it just looks too out of focus. As said before, the cause is the scattering of the light of the stars on the blue dust and it affects only the stars immersed in the dust. But since these Lodestar files are so small, I also include another version that appears less "out of focus". This was made from the same stack a few minutes later but without the x^0.25 option. So the white core of the stars is bigger, covering most of their blues scatter halos. Clear Skies! --Dom
  20. Milky Way Petroglyphs LDN772 in Vulpecula B138 in Aquila Single 5 second exposures with Samyang 135mm lens at f/2.0 and Ultrastar Sr. Both open for interpretation. Clear Skies! --Dom
  21. Here is my latest and definitely the last attempt at the Small Sagittarius Star Cloud for the year. It is taken with a monochrome Ultrastar Sr. (SX-825 with cooling not turned on.) I don't know, if it is better than the earlier versions but at least I tried to do what I wanted. Despite of the gloomy forecasts, the night started out clear. Unfortunately, by the time I set up and polar aligned, clouds moved in and didn't depart before the entire object sunk below the horizon. The grayish stuff on the left side of the image is the effect of these high clouds. Unfortunately they are not just obscuring haze but they are also reflecting the light pollution of the urban area (Seattle). Anyway, this capture is of a narrower FOV taken with a 135mm focal length lens (as opposed to the 85mm of the earlier captures). This is a good sharp lens. The image consist of a mean stack of three 60 second frames taken with a 7nm H-alpha filter and then three 1 second frames taken with a luminance filter added to the stack using sum stacking. This technique makes use of the new capability of the current version of StarlightLive to switch between different stacking modes. The H-alpha exposures are assigned to the red channel and the luminance frames are assigned to all channels. Without switching between the stacking modes this would not be possible. My goal was to show M24 in its full physical complexity. This is a very interesting and unique object. The star cloud is essentially an enormous open cluster of young O and B type stars that are still embedded in the cloud of Hydrogen gas that they were born of. They ionize the gas that then glows red. I wanted to display both the red glow of the ionized Hydrogen and the white light of the stars in the same image. Aesthetically the plain black and white simple H-alpha capture of Post #2 may look more elegant and pleasing. But in my opinion, the three color red, white and black image better conveys the physical structure of the object. That we see its two different physical layers, we see it in two stages of its cosmic evolution, gaseous and stellar, that are still simultaneously present. Anyway, this is it for M24 for now. We should revisit it next year, when it is higher in the sky and there are no clouds interfering. Clear Skies! --Dom
  22. Chris, I don't know how short of focal length you plan to use and I don't know your taste regarding chunkiness. So instead of giving recommendations or advice based on theory, I offer some examples. Then you can decide what is acceptable to you and what isn't. Here is a capture with 14mm focal length optics and Lodestar. This is the shortest focal length I have personal experience with. (This is a rarely seen view of Barnard's Loop and friends, so I include the outlines of Orion for orientation.) You can find examples of captures with the Lodestar and optics with focal lengths of 24mm, 85mm and 135mm on this thread https://stargazerslounge.com/topic/265965-from-winter-towards-the-summer-along-the-milky-way/?page=1. There are further examples of captures with focal lengths between 85mm and 1000mm in this album https://stargazerslounge.com/gallery/album/3729-widefield-lodestar/. The titles of the images in the album always start with the focal lengths of the optics used. So if you sort the album by the image titles, you get them in the order of increasing focal lengths. The focal lengths are also always included in the annotations on the images themselves. Most of the short focal length optics that I own are camera lenses. They are essentially achromats. A few of them, like the Nikkor 180mm, Nikkor 300mm and Samyang 135mm have an ED element. The others don't. This doesn't give you advice on which camera to buy. But at least shows you in examples how chunky things get with the Lodestar in real life scenarios. Clear Skies! --Dom
  23. Thank you Rob! As I said in the post, I am still experimenting with this technique. That's why I didn't get into explaining it in more detail. Things will probably still change. If you look at the subscript of the first posted image, you see that it was made of two frames. The two frames were merged using the stacking routine of StarlightLive. I said that it wasn't a stacked image because, in my mind, I reserve the word "stacking" for the action, when exposures of the same object are merged with the purpose of reducing noise and improving image quality. In the current case the two frames that were merged were very different. They were captures of two different physical layers of the object. The first one was a black and white image of a star field. The second one was a capture of a red extended gaseous nebula. Due to their very different nature, no noise reduction or image quality improvement occurred, when the two frames were merged. I hope that this clarifies my usage of words. At least somewhat. Clear Skies! --Dom
  24. For comparison, here is a black and white capture of the Small Sagittarius Star Cloud from last summer. It is rotated to have North up and was taken with a better lens. This is a pure H-alpha capture. It also shows the Hydrogen gas but it doesn't jump out as obviously because of the lack of color. The stars are so tiny and pin point, because this is just their H-alpha component. In H-alpha stars are always nice and tiny. Clear Skies! --Dom
  25. What Does a Starfield Hide? I am experimenting with using the multi-spectral feature of StarlightLive to capture wide field images of the sky and also display the H-II regions of the same areas. I would have liked to continue with this thread, where I left an earlier thread near the Pipe nebula area in Southern Ophiuchus https://stargazerslounge.com/topic/265965-from-winter-towards-the-summer-along-the-milky-way/?do=findComment&comment=2912530. But as work didn't allow me to have any astronomy outings during the summer, there will be a gap. To start as South as I can from latitude 47 at the end of September, I aimed at the Small Sagittarius Star Cloud M24. I am not very knowledgeable about celestial objects and didn't know what to expect. I was surprised by the amount of H-alpha that I saw, in particular behind the star cloud. Here it is. (BTW North is towards the left of the image.) I checked with Astrometry.net and it identified only two Hydrogen nebulae, the well known and obvious IC 1283/84 and IC4701. As I am only in the early stages of experimenting with this real-time RGB+Ha overlap technique, I seriously thought that all the red that seems to protrude from below the star field is just some false positive. A dense area of the Milky Way that the H-alpha filter picks up as a continuum. But then I read more about the Sharpless objects and found a statement that "Sh 2-38, Sh 2-40, Sh 2-41 and Sh 2-42 all appear to be embedded in the Sagittarius OB4 association." So it seems that the entire M24 star cloud is an enormous group of young stars still swimming in the cloud of Hydrogen from which they were born and ionizing it with their UV radiation. According this, the red mat, that we see to extend over the edges of the star cloud, especially in the corner near the black nebulae, is just that gas cloud and has the Sharpless numbers mentioned in the quote. Here is a version annotated as well as I could. Except that I didn't label Sh 2-38, Sh 2-40, Sh 2-41 and Sh 2-42 as I didn't know which number refers to which part of the Hydrogen cloud and too many numbers would have just over-crowded the image. As said, the technique of making these overlap captures is still in an experimental state. For these captures I didn't stack at all, I just added up the components. I was planning to continue with this same object today using a better lens and stack more frames. But clouds moved in, rain started and I am not likely to be able to return to this object any more times this year. It was already very low with the horizon cutting into the image after 9 pm. The trick that needs more practicing is to prevent the H-alpha exposures from tripping up the natural neutral color balance of the stars. As you see, I was more successful with this on the second capture. The images were captured with an 85mm camera lens and an SX-825 mono camera. They have been cropped to about 85% size to fit within the posting file size limit and to cut out the obnoxiously bright and blown out Omega Nebula M17. I apologize for my lack of in-depth knowledge about the objects and the tentative experiemental nature of the captures. But the curtain has just rolled down on this object for the year. I can post whatever I have or wait until next summer. I plan to continue this thread, as time permits, with hopefully better captures of other objects from along the Northern arch of the Milky Way. Clear Skies! --Dom
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