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About alan4908

  • Rank
    Proto Star

Contact Methods

  • Yahoo

Profile Information

  • Gender
  • Interests
    Astrophotography ! ....at the moment I'm concentrating on deep space imaging
  • Location
    East Sussex
  1. An LRGB image of two spiral galaxies that have collided and are now moving apart. Whilst the devastation of the impact was immense, you can still see a faint spiral structure in the smaller (NGC4485) galaxy. The larger galaxy (NGC4490), which is also known as the Cocoon galaxy, also shows a large Ha region. Collision debris can also be seen between the two galaxies. The image represents about 12 hours integration time and was taken with a SW Esprit 150 and a Trius 814 camera and was previously posted in the Deep Sky imaging section. Alan LIGHTS: L:13, R:19, G:20, B:21 x 600s, BIAS:100, DARKS:30, FLATS:40 all at -20C.
  2. Interacting galaxies

    Thanks Barry. My imaging scale is 0.7 arc seconds/pixel. The image is definitely cropped ! - Since I'm not entirely sure how you quantify a cropped image wrt to the original size.... PS informs me that the original image, including stacking alignment errors, in TIFF format is 3388 x 2712 pixels at 72 pixels per inch = 9188256 pixels. The cropped TIFF is 1113 x 1392 pixels at 72 pixels per inch = 1549296 pixels. So the area cropping factor is 9188256/1549296 = 5.93, which means the cropped image represents c17% of the initial image area. If you take a digital zoom perspective, then the cropped image represents a digital zoom equipment of Square Root (5.93) = 2.4x Alan
  3. Interacting galaxies

    Thanks Richard
  4. Interacting galaxies

    Thanks Olly, I'm glad that you like the image processing. Yes, I have found that my Esprit 150 is delivering the goods particularly well on galaxy images. Combined with the fact that it is virtually maintenance free, it does make a compelling proposition ! Alan
  5. Sunflower galaxy

    Thanks Galen ! Alan
  6. Interacting galaxies

    Thanks - yes, it doesn't often appear here - maybe because it appears quite small in the sky. Indeed. Yes, quite interesting to see all those star forming regions after the collision. Thanks for the comment DP. Thanks. Considering it's angular size I was pleased to capture some detail, I also like the variety of the colours ! Alan
  7. Interacting galaxies

    The image below illustrates what happens when two spiral galaxies crash into one another..... They are now somewhat less spiral shaped than before the crunch and you can also see the debris trail between them. Apparently, they are now heading away from each other. The larger galaxy is NGC4490 (aka the Cocoon Galaxy) and the smaller one NGC4485. Whilst this is an LRGB image, I was quite pleased to see some Ha regions clearly visible. The image represents just over 12 hours integration time and was taken with my Esprit 150. Alan LIGHTS: L:13, R:19, G:20, B:21 x 600s, BIAS:100, DARKS:30, FLATS:40 all at -20C.
  8. An LRGB image of the Sunflower galaxy. The image was taken with my SW Esprit 150 and SX Trius 814 camera and represents just over 10 hours integration time. I gave the very bright stars near the galaxy a very modest stretch and then blended this result with the result of the more highly stretched galaxy image. This approach generated some star colour and also reduced their distraction effect, in addition, it also allowed some faint nebulosity that surrounds the galaxy to be displayed. The image was processed with my normal workflow which uses three software packages: CCDstack: calibration, stacking & error rejection, Lum deconvolution and DDP stretch, RGB combination Photoshop: mask generation(s), High Pass Filter, colour enhancements, noise reduction Pixinsight: gradient reduction (DBE), Photometric colour calibration, green reduction (SCNR), noise reduction (TGVDenoise), sharpening (MLT). The image was previously posted in the Deep Sky imaging section. Alan LIGHTS: L:11, R:19, G:15. B:17 x 600s, DARKS:30, FLATS:40, BIAS:100 all at -20C.
  9. help with elongated stars please

    Glad to be of assistance. The CCDInspector results do not indicate if you are too close or too near. I suspect that you are close to the optimum FF/FR distance and I'd suggest that you remeasure the result after you have corrected the tilt. Personally, I suspect that you will get quite a good result once you have corrected the tilt. Alan
  10. help with elongated stars please

    The CCDInspector results are indicating that your camera is slightly tilted with respect to the objective in the direction indicted by the arrow. The amount of curvature (20%) is an estimate of how effective the field flattener is performing. If I compare this to some images taken with my ED 80 with the matched 0.85 FF/FR using a Trius 814 camera then I was typically getting a curvature of about 15% and a slightly lower tilt. To me, this indicates that you are slightly out in terms of your optimum FF to camera spacing in addition to your camera tilt. I'd suggest that you concentrate on fixing the camera tilt and if you are still not happy with the image result, then vary the FF to camera spacing until the field curvature is minimized as a separate process. On the camera tilt front, I'd suggest taking some shots with the scope pointed vertically since this should reduce the impact of focuser droop - if you still see the tilt then you need to correct if by slightly tilting the orientation of the camera with respect the objective. Certain camera's and focuser's have the ability to make slight tilt adjustments, if yours do not then you could buy one of these https://www.firstlightoptics.com/adapters/flo-m48-t-tilt-adjuster.html (check that these threads are OK for your setup). On the other hand, if the tilt disappears then it suggests you have focuser droop. As an aside, if you want to obtain the most accurate image results with CCDInspector - feed it the calibrated but unstreatched FITS files and average over a number of images. Never run the analysis on jpeg images or images that have been processed since you'll get misleading results. Alan
  11. M97

    Thanks for the comment - I agree it does look a little strange !
  12. Deep Sky III

    Images taken with a Trius 814 and a Esprit 150
  13. Galactic grouping

    Thanks Paul Glad to be of service John ! Alan
  14. Galactic grouping

    Sure - firstly, open an image that you want to annotate. You first need to plate solve the image so go to SCRIPT->Image Analysis->Image Solver. Use the search option to get the RA/DEC coordinate of your object your plate solving. Select the solved image and then go SCRIPT->Render->Annotateimage - when you do this - various options will appear that allow you to customize your output. Alan
  15. Galactic grouping

    Thanks Ady Thanks - yes, I was happy to capture a little detail on these guys. Hi John - the annotated image was generated with Pixinsight - it gives various options that allows you to customize the output eg font size, stars on/off etc, so that you can tune it to generate a non-cluttered result. Alan