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Laurin Dave

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Posts posted by Laurin Dave

  1. The Coma Cluster through Esprit150SX46 for 6hrs Lum and Esprit100ASI1600 for 2 hrs each RGB captured on 14,15 and 16 April....  Quite a few here, PixInsight says 89 NGC/IC and 529 PGC galaxies..

    Coma_Cluster_LRGB_Final_22Apr21.thumb.jpg.4168b5c526d9f0de4aeaf4e979898b07.jpg

    The core inverted and superstretched showing supergiant ellipticals NGC4874 and NGC4889 and some of their enormous 1 million lyr diameter halos

    Coma_Cluster_NGC489_NGC4874_200pc_Annotated.thumb.jpg.cafc98285c851341e4a91002f3341427.jpg

     

    The Coma Cluster (Abell 1656) is a large cluster of galaxies that contains over 1,000 identified galaxies. The cluster's mean distance from Earth is 321 million light years. The central region is dominated by two supergiant elliptical galaxies: NGC 4874 and NGC 4889. The cluster is within a few degrees of the north galactic pole on the sky. Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster.

    NGC 4874 is a supergiant elliptical galaxy. Discovered by William Herschel in 1785. The second-brightest galaxy within the northern Coma Cluster, it is located at a distance of 350 million light-years from Earth. The galaxy is surrounded by an immense stellar halo that extends up to one million light-years in diameter. It is also enveloped by a huge cloud of interstellar medium that is currently being heated by action of infalling material from its central supermassive black hole. A jet of highly energetic plasma extends out to 1,700 light-years from its center. The galaxy has 18 700 ± 2260 globular clusters.

    NGC 4889 is an E4 supergiant elliptical galaxy. It was discovered in 1785 by William Herschel. The brightest galaxy within the northern Coma Cluster, it is located at a median distance of 308 million light year from Earth. At the core of the galaxy is a supermassive black hole that heats the intracluster medium through the action of friction from infalling gases and dust.

    As the largest and the most massive galaxy easily visible to Earth, NGC 4889 has played an important role in both amateur and professional astronomy, and has become a prototype in studying the dynamical evolution of other supergiant elliptical galaxies in the more distant universe.

    NGC 4921 is a barred spiral galaxy in the Coma Cluster, located in the constellation Coma Berenices. It is about 320 million light-years from Earth. The galaxy has a nucleus with a bar structure that is surrounded by a distinct ring of dust that contains recently formed, hot blue stars. The outer part consists of unusually smooth, poorly distinguished spiral arms.

    NGC 4911 is a disturbed, warped spiral galaxy with a bright prominent central starburst NGC 4911 is believed to be interacting with its warped, barred lenticular companion (or any of its many other nearby companions), producing the enhanced star formation and shell-like appearance seen in optical images. The galaxy contains rich lanes of dust and gas near its centre. The existence of clouds of Hydrogen within the galaxy indicates ongoing star formation. This is rare for a spiral galaxy to be situated at the heart of a cluster.

    source Wiki
     

    thanks for looking

    Dave

    • Like 12
  2. Here's another one through an Esprit150 with an SX46 from a couple of years ago...  on the left lightly stretched 9x1200s lum and on the right an even more lightly stretched single sub at 800%..  like others I was surprised to see it..  

    Good luck with 3C-273 Steve!

    Dave

    M87_Jet.thumb.jpg.7801bc5e3ae9c9940abe3b47db29b3bb.jpg

     

    • Like 3
  3. 33 minutes ago, old_eyes said:

    I used the fits header data from affected frames to see where the scope was pointing at the time.  What were the Alt-Az coordinates? Then, on a cloudy night, I moved the scope to the worst position and eliminated sources one by one. That is when I found it was the security camera.

    Clever!

  4. 7 minutes ago, DaveS said:

    I had some light ingress problems which I think might be due to the IR LEDs of my obsy CCTV, after the meridian flip

    Before flip

    1607608150_M106-Luminance-0005Beforefliplinear.thumb.jpg.8220732e0b9a61d174f87a3f530a8056.jpg

    After flip

    1187356019_M106-Luminance-0017afterfliplinear.thumb.jpg.ae1e461e10dfa0dce395e129b2e4a5f5.jpg

    No calibration, just a brutal linear stretch, but the streak is visible in the stacked subs given a more gentle stretch.

    I have a Hoya IR76 on order from EO which I hope will cut off the iR LED emission before the Luminance pass-band.

    Is that with an OAG Dave?  I sometimes get light leaking down gap around the stalk...  insulation tape fixes it..

  5. 38 minutes ago, wimvb said:

    .......    at times, it looks like Chewbacca. I guess I should print the other orientation and hang it on a wall.

    @Laurin Dave: I gather you visit that other forum as well. :D

    Indeed I did Wim...  it was a journey to the Dark Side...  maybe that's where you saw Chewbacca.... :) 

    • Like 1
  6. No idea what the numbers mean but that looks fine to me, good I'd say from Bortle 8 and 400mm.    Here it is, all I've done is cropped all the edges back, re-sampled by 50%, (I expect that drizzling is just adding noise)  removed light pollution and given it a histogram stretch.   Plenty more to give with more processing..  Beware of Pixinsight Screen Transfer function stretch it is highly aggressive.  I'd suggest you re-integrate without drizzle and go from there .

    20_hour_drizzled-lpc-cbg_HT.thumb.jpg.c6800a6907c5604353c3326c9becbd01.jpg

    • Thanks 1
  7. Here's my attempt.... A combination of Pixinsight and Photoshop..... process I followed below image..

    M33_IKI_L_HaRGB_Final_12Mar21.thumb.jpg.ec90ca5365edce8bff68c20466f01c0d.jpg

     

    Firstly RGB in Pixinsight... Linear Fit of Blue and Green to Red channel, RGB channel combination..  a touch of DBE..  run HSVrepair script to repair star core colour, recombine H, S and V channels...   ArcSinh stretch at 7, light touch Histogram Transformation then Masked Stretch, save as 16bit tiff. 

    Luminance in Pixinsight ... a touch of DBE, then Histogram Transformation .. save as 16 bit tiff..   apply Masked Stretch  and again save as a 16 bit tiff.. 

    Hydrogen Alpha..   Histogram Transformation,  remove stars with StarNet.. save as 16 bit tiff .... 

    Photoshop ..  open RGB, convert to Lab colour mode, increase contrast on "a" and "b"  channels by 30%, convert back to RGB mode..  Make two copy layers...  set top to "Soft Light mode" .... merge with middle layer... set merged layer to "Colour" mode" and merge down...   

    Duplicate RGB image and split into RGB channels..   open starless Ha..  increase contrast..  copy and paste Ha onto Red Channel, set Ha to blend mode "Lighten" ...  fiddle about with levels and contrast (applied to the Ha layer only)  so that only the Ha regions change brightness..  Copy the combined Red/Ha image and paste back into the Red channel in the RGB image..   do the same with Green and Blue but lower the opacity of Ha to around 7 for Green and around 15 for Blue (this make the Ha a bit pink)..  Save as HaRGB image ..   

    Open the Histogram stretched Luminance... copy and paste it onto the HaRGB image..  set blend mode to Luminance and 20% opacity..   increase colour saturation in RGB layer by say 10%..  apply Gaussian blur of 0.6 pixels to RGB layer ..  merge down..... repeat 5 times, although maybe skip the colour saturation and blur steps on later ones if it gets too saturated..  save as L_HaRGB image..   

    Apply Noel's actions  "Star Reduction" and "Increase Star Colour" .. save ..  Apply Noel's action Local Contrast Enhancement.....  set as "Layer On Top"..  decide which areas of the LCE enhanced image you like and at what opacities and apply them to the base image using copy layers..  Save image..   

    Open in Pixinsight..  extract Luminance... run StarNet with "Create Star Mask" ticked..  when complete subtract the Star Mask from the Starless image using PixelMath...  apply the resulting image as a Mask ..  apply Multiscale Median Transform sharpening to the Luminance channel of the image with Layer 2 bias set to 0.2 and layer 3 bias set to 0.1...  save image..   

    Open in Photoshop and also open HT and Masked Stretched Luminance image ..  apply Luminance to L_HaRGB at 20% .. save image..  

    Open In Pixinsight...  apply Script "Dark Structure Enhance".... save image ..  Open DSE and non DSE image in Photoshop... merge together to taste..  crop edges rotate 180 degrees and save,

    Dave

     

     

    • Like 3
  8. Captured between 26Feb and 1 March, an end of season Orion Mosaic including part of Barnards' Loop, M78, the Horsehead, Flame, Running Man and Great Orion Nebulae and the three stars of the Belt. Consisting of nine overlapping panels of colour with the Askar200/ASI2600mc totalling 7.5hrs and eleven panels of Ha with the Samyang135/ASI1600mm totalling 9hrs.   I've added high resolution data from Esprit100/X46 and Esprit150/SX46 images to the M78, Horsehead and  M42 areas.  Each panel was calibrated/debayered in Pixinsight and integrated in APP, then cropped and registered in Pixinsight using the Mosaic by co-ordinates script, gradient corrected using Pixinsight's Photometric Mosaic script then each corrected panel was fed back into APP for final integration.  Initial stretching in Pixinsight then into Photoshop for colour enhancement, adding the Ha to the RGB, star size and noise reduction and to blend in the Hi Res Data.  Then back to Pixinsight for a final crop and resample to 50% (7.5arcsec/pp).   Its somewhat noisy and not one for the pixel peepers.

    Thanks for looking

    Dave

    Orion_Mosaic_M42_Horsehead_M78_BarnardLoop_Final_50pc.thumb.jpg.eb41b1e6122c90c3df1dc106d8e728a9.jpg

     

    • Like 40
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