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About Peje

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    Proto Star

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  • Location
    Lisburn, UK.
  1. Peje

    Strange Flats

    The ND Film arrived and works well with two sheets, my slight issue is the times for my LRGB are wildly different to my NB. I'd imagine this is because my LED panel favours the Blue and Green LED's. *** 1x1 *** Ha 33 Sii over 1min (too long to do) Oiii 9.2 L 0.4 R 3.1 G 0.85 B 0.75 *** 2x2 *** R 0.8 G 0.22 B 0.195 After things about it in work, anything longer than about 0.01 (1/100s) will not be able to capture LED flicker. I think my only option, other than to replace the panel, is to fit only one sheet permanently and add either one or two sheets when I need LRGB flats. Now back to some more testing!
  2. I gave in to temptation and stacked 11x600s with the Baader CC then 9x600s with the Skywatcher. The image below is just a stack of calibrated lights, no processing. I was surprised that the detail increase is a little more subtle than I expected, but the star size reducion has been really impressive. Also, the star shape seems to have dramatically improved. Bloated stars were the main thing that displeased me in my images so I'm really happy that this very simple change has made such a difference. Now I just need some clear sky to start capturing some nice data
  3. Peje

    Strange Flats

    Yes, both captured with same software (SG Pro) and using same PC. All my gear is permanently mounted in a shed of it's own.
  4. Peje

    Strange Flats

    Had to take my time over this one Q: Is the gradient seen in the flats aligned perfectly left-to-right as seen at the camera when the long axis of the sensor is aligned exactly with the long axis of the OTA A: No, I am seeing a slope, perhaps about 30degrees. I am using laser collimators so it is quite possible this is introducing a gradient as you suggest. Q: When you did the ‘tee-shirt’ flats where these sky flats or were you still working in the shed with the LED panel? A: Both; I firstly used the sky, then used my flats panel sitting on the far wall so as not to create shadows. I didn't notice any difference between the two. Q: this may be due to relections caused by insufficient blackening of the focuser port, focuser draw tube and all the mechanical couplers etc used to attach the camera to the focuser. {OK, this is not a question but I like uniformity!} A: This is proably going to be more of an issue for me now as I've noticed my new CC is pushing my LP filter down into the main tube. I'm hesitant to paint it but I don't think I'll have much choice. Q: Some of the Skywatcher models I have seen don’t seem to use a ‘black’ baffling paint, more like ‘dark grey’ {Again, not a question} A: Yes, the inside of the tube is dark grey, I do have matt black paint that I used for the Moonlite focuser bolts as they came silver. I like your idea of testing using flocking, I think I still have a few A4 sheets lying around. Ultimately, if my flats are representative and effective then I'm happy with that. My main other concern is what effects my LP filter protruding into my tube may cause.
  5. I spend some time trying to do starless images but never found a method / result I was happy with.
  6. Thanks William. These images are the raw 600s ha subs in SG Pro given a low stretch. The difference blew me away. Initially I thought it might have been a focus mismatch but I remember spending quite a while getting good focus on Tuesday night.
  7. Finally got the SKywatcher f/4 CC. The difference is extremely noticeable. I'm comparing images from Tuesday with old CC to one from tonight with the new one.
  8. Peje

    Strange Flats

    T-shirt flats yielded same results. Interestingly I rotated the imaging train in the focuser and the dust stayed where it was (as expected) but the shadow pattern moved. So this is coming from inside my scope and somehow it's not affecting my Ha & Sii
  9. Peje

    Strange Flats

    Excellent. I'll have to wait until it gets dark again to do my flats as the daylight is pretty variable due to clouds at the minute. At least it means I can fit my new coma corrector tomorrow. Thanks for your help.
  10. Peje

    Strange Flats

    I did some daylight flats this morning and the gradient is also there. I've attached the image. The gradient doesnt seem to be there with 1-2k flats which may explain why it's not there in my lights. That being said, I guess it could be present in an uncalibrated stack of lights if the ADU came up enough
  11. Peje

    Strange Flats

    So you think the bright top corner and dark lower corner is acceptable?
  12. Peje

    Strange Flats

    Sorry, should have uploaded JPEGs
  13. Peje

    Strange Flats

    Another piece of information, when I shoot 1k ADU to replicate the level of my lights I don't get the strange gradient so perhaps these flats are actually reasonable.
  14. Peje

    Strange Flats

    Here are the complete set of flats, I've put the times in the file names Blue 2sec.fit Green 1.8sec.fit Ha 20sec.fit Lum 0.7sec.fit Oiii 12sec.fit Red 2.2sec.fit Sii 35sec.fit
  15. Peje

    Strange Flats

    Even more confused now... I moved the LED panel and dimmed it with paper, now it just casts a light around the walls of my shed. I adjusted the paper so that the Oiii exposure needed 12 secs. I've attached the image, the flat is exactly the same as before. I can't figure out what's causing this, it's also the same for my LRGB but not my Ha or Sii. Tomorrow I'm going to try using some daylight to make the flats (inside the shed) so that will rule out the LED panel completely. Really open to any advice, my new coma corrector arrived so I need to get my flats done before I remove the current imaging train.

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