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Adam J

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About Adam J

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  1. Ok where to start. The Astronomik OIII filter you purchased belongs to a class of filter know as a narrow band filter. These filters are specifically designed to filter out the very narrow emission wavelength associated with transitional modes (emission lines) within the electron shells of certain elements. So that was the technical version... The Layman version is that the filter you bought only lets through emissions from Oxygen 3 (OIII) so the Oxygen atoms within nebula. The wavelength of that light is green so when you take a picture only green light gets to the sensor and hence the image is green. The bad news is that there is no full color data to retrieve only the green OIII light was let through. I am sorry to say that you have been poorly advised, if you want to take one shot color images with your DSLR. An OIII filter will block light pollution yes but it wont let you take a color image. In moderate light pollution I would have advised a CLS CCD Clip filter. In medium light pollution I would have recommended a UHC Clip filter. In very bad light pollution I would then recommend narrow band filters, H-a would have been a better choice as your first one. Also of note is that narrow band filters only work with nebula really, the UHC too mostly. The only one i would recommend for galaxies at all is the CLS filter. OIII can work with DSLR's for nebula depending on the exact one you have and the ambient temperature which needs to be low to allow very long exposures. However, depending on the rest of your setup you may not be able to get the OIII to work. Here is an example of what you can get with an OIII filter with a DSLR (once stacked converted to mono, originally was green). But this is a cooled DSLR with long (10min) exposures. You will get decent images of brighter nebular but I dont want to oversell it, you are unlikely to get that kind of result with a un-cooled DSLR and short exposures. You can combine several separate images taken with several separate narrow band filters to get color but I am not sure you really want to go down that path. Most likely what you actually want it a mild UHC filter. But I would need to know more about your setup and what you want to image before I would make a definitive recommendation to you. For example to make best use of any filter your DSLR needs to be modified. I can only think that the chap who advised you was thinking about visual filters not imaging with a DSLR.
  2. I chose to insulate the exterior walls of the enclosure as opposed to the interior walls, this allowed the interior to remain uncluttered and made it easier to mount components to the internal surfaces. (I later added additional insulation in select locations on the inside). This leaves the insulation open to the environment and it was necessary to select a durable material, a light weight insulation such as expanded polystyrene would likely become damaged during use. I settled on neoprene foam rubber to insulate the exterior of the enclosure due to it’s excellent thermal properties (its used in wet suits) and ability to absorb impacts. Neoprene can be purchased in sheets of varying thickness and in this case 10mm thick material was selected as the optimal balance between bulk and insulating efficiency. I should also be noted that 10cm was selected to match the thickness of other components and spacers were fabricated for the rear thumb screws to allow them to tighten flush to the surface of the insulation. Neoprene can be easily cut using a sharp craft knife / steel ruler and can even be shaped using 120 grit sand paper in order to achieve an aesthetically pleasing finish (a face mask should be used when sanding). Cut outs were made in the neoprene insulation for the water block, rear interface panel and telescope focusing tube / coma corrector. The neoprene was fixed to the outer surface of the enclosure using super glue gel following preparation with sand paper. To be continued:
  3. Color balance is tricky you can correct it but what is correct....for example is this better or worse no idea lol.
  4. The camera is full spectrum modified. I use the non IR blocked Asrtonomik CLS Clip along with an IR/uv block. I have had it cooled for a long time, but only just getting around to writing it up in this thread in the DIY astronomer section: I am in a yellow zone, i get bad gradients without it. It tends to make things look purple but you can correct in processing, this is only my third galaxy so am no expert. I normally focus on nebula. You can only try with and without.
  5. Thanks guys not sure about it as I have hardly ever done any galaxy shots this is my third ever or something. Difficult to gauge. I have focused on Nebula in the past.
  6. 50 x 300s ISO800, CLS Filter, HEQ5pro, 130PDS, Cooled Canon 550D. I am not sure if its worth continuing at 5min exposures or to add 10min exposures to help bring out the outer spiral arms more and merge in PS? Or will that detail eventually come out at 300s if I increase the total exposures up to about 100? Thanks for looking
  7. M101, 50 x 5mins ISO800, Over Two Nights, 130PDS, HEQ5pro, Orion + QHY5L II Mini Guider, Astronomik CLS Filter. Having trouble with color balance, let me know what you think guys I may add some longer exposures next to bring out the fainter trails of the spiral arms more and then combine them with this image.
  8. With a DSLR F6 or lower as a minimum, preferably F5 or lower mate.
  9. So the consensus is that its not really caused by DSS its PS not being able to balance the background and increase saturation correctly? I have star tools and dont see anything relevant. I have a very very old copy of PixInsight LE, never really use it as I find it lacks the features of the newer full version. Might that have this function available I will have to get an account and upload the stacked TIFF file. This is the stacked needs many many more exposures to be anything good but it was only 5 min exposures, I suspect that was insufficient anyway so will likely triple that to 15mins and try again rather than add more at 5 mins. Update: I have just had a play and now I seem to have some colour at least...not sure about the balance. No idea what I did differently this time, very annoying. Any opinions? I know its not great but my setup is entirely unsuited to imaging this type of target. (highly cropped).
  10. Seems to work fine with nebula...but they have more colour in them to start with. Are there any free alternatives to DSS?
  11. Correct...though I am having an issue in that I seem to have star colour in the subs but non in the stacked image... Increasing saturation in PS is just giving m101 a slightly pink tone... there is a chance, how would I get it to you?
  12. Hi all, Its galaxy season and I am out of my depth again, I am in a reasonably light poluted area and so I use H-a and OIII filters for nebula and a CLS filter for galaxys. Problem is that the colour balance with the CLS filter is so horribe that I generally end up giving up and converting the image into black and white.... So some questions: 1) Would it help to set a custom white balance in the camera (550D) with the CLS filter in place and instruct DSS to use that? 2) Are there any techniques for correcting the white balance and getting some nice colour into my image while using the CLS filter? Perhaps separate out the channels and then process them independently + recombine? 3) Could I perhapse use a two stage approach to taking the image, use the CLS filter with a group of subs and convert to mono for a luminance channel and then remove the CLS to get some colour data? All help appreciated
  13. m44

    Number of exposures? ISO? and exposure length please
  14. In order to create a broader surface to the rear of the box to mount the rear access panel against four strips of 1cm thick acrylic plastic where glued around the outside perimeter to the rear of the box with the aim of providing a wider surface with which to create an air tight seal against the rear access panel. In order to achieve greater rigidity the stand alone rear access panel was fabricated from a Carbon / Glass fiber composite similar to carbon fiber but less expensive in preference to ABS plastic. As the CO2 laser is not able to cut this material the rear panel was produced using the previously described paper template method. A paper drill template was also printed and used to align the screw holes produced in both the back panel and the orange plastic ridge to the rear of the cool box. These holes were then taped with a M4 x 0.75 threads to allow the rear panel to be secured using 8 x nylon thumb screws. A rear interface panel (containing the temperature display, USB and power connectors) was added to the access panel and set proud of the surface by 10mm to accommodate the thickness of the insulation material to be added later. To be continued:-