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Posts posted by robindurant

  1. 13 minutes ago, michael8554 said:

    If it's not on your Flats, it is on the lens or sensor.

    Is your mod Ha or Full Spectrum ?

    If Ha, then the #LPF-1  I.R. and Sensor Cleaning filter remains, so you can't clean the sensor, only the filter.

    Did you clean with a puffer, or with the Sensor cleaning function ?

    As Peter suggested a daytime AV image of a plain background with the stock 18-55mm should eliminate the Samyung.



    The Mod was just to remove the i/r filter not full spectrum I believe. Ive had this done with other Canons twith no problems . I cleaned with a Sensor Cleaning Swab and after a air blower. I have tested the Samyang on another DSLR and it works fine so its a camera problem

  2. 2 hours ago, PeterCPC said:

    Have you tried to repeat the problem by taking daylight images against a plain background?

    Here are 3 images - single shot - 10 second single frame and 10 second stretched on levels and curves trying to detect a problem

    image 1 single.jpg

    image 2 single 10 sec stretches .jpg

    image 2 stretched 10 sec.jpg

  3. 1 hour ago, gajjer said:

    Just a thought, but might it be on one of your flats? What happens when you stretch without either darks or flats?



    Have tried stacking with and without flats and darks, just the same

  4. Can anyone help me, I have a Canon 5dMk2 which is assto modded but cannot obtain a good image using my Samyang 14mm 2.8 lens, I have attached two images which I have processed to accentuate the problem , one stacked DSS and one Sequator , both show the same probem. I have cleaned the Sensor so dont know what that bottom right artefact is. Both images were stacked with Darks and Flats and captured at - 20 x 15 secs iso 3200 f2.8

    image 1.jpg

    imag 2.jpg

  5. 19 hours ago, jambouk said:

    Are you using a 2” or 1.25” nose piece? If the latter use the former; if the former a focal reducer may help, though may introduce other issues. It is a massive sensor so I think you are always going to get some vignetting. Flats will help.

    I’m using a 2”




  6. 13 hours ago, happy-kat said:

    If you take an exposure on a static mount of say 5 seconds can you see the same elongation bias on one side, take the same again but no filter, do they compare in elongation bias. I guess aim true east or west 30• to give a control position.

    How do you know it's not the optics?

    Just thinking of what I'd do to see what was contributing.

    Hi single shots even at 30 secs are OK and Ive checked and cleaned all the optics

  7. I have attached 2 images from last night using an H-Apha filter due to the Moon being up, however the target was well away from it and should according to the Filter specifacation not effect Ha imaging.

    I reduced the exposure to 60 seconds as suggested by many and set iso at 3200 ( grainy but a good setting for accenting  the problem) 10 and 5 exposures, stacked them with Deepskystacker, part processed on PS .  As you will see it has made no difference whatsoever to the rotating marking or smearing effect

    I have checked the optics in the Scope and the DSLR

    Could this be a camera sensor fault or dodgy DSS software, although it stacks with no effort.

    I have tried every settng on "Preference" on DSS inclusing the ones for Ha images, makes no difference

    Im now at a loss as to what to try next

    ROTATION 1.jpg

    ROTATIon 2.jpg

  8. On 06/01/2020 at 09:59, carastro said:

    I presume you are not in a position to get an Equatorial mount.  I am afraid you are going to be stuck with these problems all the time you have an Alt/Az mount making your imaging life far more difficult than it need be.  


    No Im in a situation where I can only veiw from SE - SW  but have produced reasonable images, this is new

  9. 15 hours ago, steppenwolf said:

    You *could* do this manually but it must be done in between exposures. Set the handset slew speed to minimum and just ‘brush’ the control pad direction keys in a random pattern.

    What you are aiming for is a random position of the object that you are imaging with a minimal offset between each image.

    Many thanks Steve, I will try that

    14 hours ago, ollypenrice said:

    In this image I think you've black clipped it so much that none of the rotating noise of the first one would be visible anyway. Some field rotation remains visible in the stars, though. The only defence against field rotation with an alt-az mount is to shoot short subs. (Actually no, you do have the option of relocating to either the north or south pole... 😁

    If you're feeling diligent and have Photoshop there is a simple software dodge for making stars round. Saved as an action it can work quickly but only on one star at once. Your action, saved to a function key, should record the following once the magic wand has been used to select a star:

    -Select, modify, expand (try 5),

    -Select, modify, feather (try 3). The chosen values depend on camera-scope specifics.

    -Filter, blur, radial blur set to best quality and spin. Run the filter twice.

    -Deselect. (Don't forget to record this.)

    Once done you magic wand a star and hit the function key. Voila, round star.



    Thanks Olly


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