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Posts posted by GixerJas

  1. When I look at my subs they seem to lack sharpness, is there something I can do to improve this or I have I reached the limit of my equipment or seeing conditions?

    I know that my C8 SCT isn’t a great choice for imaging, but it’s fine until I can afford something that’s going to be significantly better (I’m not sure what that something is yet, or how much better it could be). My usual FWHM focus values are around 4 +/- 0.1 using an ASI1600MM for the imaging camera, unbinned with a 0.63 reducer.

    The mount and guiding setup seems good, typically total guiding RMS values are around 0.3 px using a ST80 with an ASI120MM.  I built an Ardufocuser and control everything through NINA, including the autofocus, manual focusing doesn’t improve the focus and an out of focus collimation check looks fine.

    I’ve attached a single auto-stretched sub as an example. And also the semi-finished image, I'm attempting to make best use of a Pixinsight trial.

    NGC 281 - Pacman-SHO.jpg

    2020-10-11_23-51-55_Ha_300.00s_0006_Pacman Nebula_1x1_200.jpg

  2. So far I've stuck with the default settings in Deep Sky Stacker, apart from choosing Sigma Clipping for the lights. I'm thinking that my subs are under exposed but as it's going to be cloudy where I am for the next few nights I'll experiment with the vast array of stacking and processing options to see how they affect the final image.

    I'm planning on trying to capture the Bubble Nebula next but I'll need to look into improving the exposure histogram, I'm wondering if it's asking too much of an unmodified DSLR?

  3. Thanks CloudMagnet for the response.

    I had some concerns when I was setting up the subs as the histogram in APT didn't look good. I was worried about either pushing up the ISO or exposure time. so I left it run and tried to stretch it as much much as possible in post processing.

    I can see what you mean about a possible reducer error, I've just switched to an inexpensive setup to allow me to screw the filter into the camera nose piece., I'll check the measurements 




  4. This is my first attempt at processing an image taken with an Optolong L eNhance filter and I'd appreciate some advice on how the image can be improved. I think that the colour balance may be a bit off, but I'm not sure if this is to be expected with a dual narrow band filter?

    My imaging setup is a C8 SCT with a 0.63 reducer and an unmodified Canon 70D. 

    The image was stacked from 35 x 300s frames at ISO 1600, plus darks, flats and bias frames. Post processing was done in Photoshop.

    Any advice will be greatly appreciated as I'm a newbie at post processing and mainly rely of action scripts and basic level adjustments.

    NGC 7380 - Wizard Nebula3.jpg

    • Like 2
  5. Inspired by the Ardufocus project, described in the post linked below from 2017, I built the focuser from the parts that came in an Arduino starter kit, printed a case and fitted it to my C8 SCT.

    I had made a fine focuser years ago so I setup the Ardufocus to turn the fine focus knob. The setup work really well manually using the ASCOM Ardufocus driver but struggles with the auto focus routine in APT and also repeated presses of the negative fast movement button where in both cases it tries to return the step count to zero.

    I've set the large step movement to 100 and the small step movement to 10. I'm wondering I need to make the large step movement bigger so that changes in the FWHM value are more obvious, but as the forecast is rubbish it's not looking likely that I'll be able experiment for a while. I'm hoping that someone else may of experience with the Ardufocus and may be able to offer some advice.

    So far the focuser has cost me almost nothing and it would be great to get it fully functional.




  6. Hello,

    Like many others finding ways to fill enforced time at home I've been inspired to return to astronomy. Unfortunately when I fired up my old ASGT mount it lasted one session and promptly died with no prospect of resurrection, which prompted me to think 'if not now, when?', so I bought a EQ6-R (very impressed). I also sorted out a guide scope and took advantage of the recent clear skies the UK has experienced.

    I've been amazed by the difference a guide scope makes. I compared a photo I took n 2009 with a one shot, unprocessed, image I took last night.

    Both taken with an unmodified DSLR and a C8 OTA, the 2020 image used a guider and EQ6-R mount. I need to add 'learning to process images' to my list of things to do.

    This forum is a great resource that I've been trawling for information to improve my images. There's lots to catch up on how cameras, filters and techniques have moved on in the last decade.


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