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DaveS

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Posts posted by DaveS

  1. I had a look at the M13 that I did last year, and realised that, although I had captured 15 subs each of RGB in G2v calibration, I only had 8 subs Luminance. With a brief clear slot I decided to collect another 4 hours Luminance, but in 300 sec subs instead of the 600 sec that I did previously. 

    Unfortunately I had odd trailing in some of the subs (Not sure why) so only 3 hours worth made it into the stack. Still, I combined what I had and made a new LRGB. I also restacked the RGB and combined them before doing a DDP and deconvolution. The Luminance also had a deconvolution applied. A slight histogram adjustment was performed to bring up the background a little, and hold back the brightest star cores, and a modest saturation boost to bring out the star colours.

    227766314_LRGBfromcombinedRGBSHSB.thumb.jpg.6cdf3606c11dd9731a8ea35c323480e0.jpg

    If I should revisit this I will pull the subs down further, probably 180 sec Lum, and 300 / 300 / 525 sec G2v RGB subs.

     

    • Like 8
  2. 21.65 is pretty dark. I have supposedly 21.66 and have seen M33 naked eye, and my eyes are pretty rubbish. My summer milky way is bright and structured down to the horizon (Helps that the nearest town to the south is in France, 350 km away).

  3. HCG 68, NGC 5371, and fuzzies.

    And a gert light streak, gah!

    Yet another Hickson Compact Group, this time HCG 68 which is at lower right, NGC 5731 is the pretty little spiral top right. The framing was chosen so as to include a lot of faint fuzzies to the left. North is to the right. The light streak is from a bright star just out of frame.

    I'm going to post this now as I can't see any clear night before the Devil's Searchlight ruins the sky again. This is 32 x 10 min bin 1 Luminance, 11 x 10 min Bin 2 Red, 12 x 10 min Bin 2 Green, and 11 x 17.5 min Bin 2 Blue (G2v calibration). I actually captured 42 Lum and 14 each RGB, but a lot of subs were rejected.

    The individual stacks were cropped to remove alignment edges and given gradient reductions. The Luminance was given a DDP with high-pass filter, and Richardson-Lucy deconvolution. The individual RGB stacks were combined into a RGB image which was given a DDP without high-pass (To preserve star cores), but with a modest saturation boost. After another crop it was upscaled to match the Lum. The LRGB was then synthesised and a light unsharp mask applied to bring out the spiral arms.

    1099932284_32101211LRGBSBUM.thumb.jpg.0c2c009f59763339d302b3b4bd85c06a.jpg

    The cropping for edge removal has resulted in NGC 5371 almost being cropped., unfortunately.

    • Like 7
  4. This is the result of stacking 31 x 10 min bin 1 Luminance, 10 x 10 min Red, 12 x 10 min Green, and 8 x 17.5 min Blue, all bin 2 with the ODK rig.

    The odd figures are due to having subs that were rejected by the AstroArt stacking routine, and by G2v calibration giving longer blue subs. I actually captured 36 x Luminance, and 12 each RGB.

    After stacking with Flat, Dark Flat and Dark frames, the stacks were cropped to remove alignment edges and given a gradient reduction. The Luminance was given a DDP with high pass filter and Richardson-Lucy deconvolution. The RGB stacks were aligned, and combined in Trichromy before DDP without high pass, but given a saturation boost. The RGB was upscaled to match the bin 1 Luminance before the Luminance was coregisterd and the LRGB synthesised. Finally a light unsharp mask was applied.

    549372971_3110128LRGBUM.thumb.jpg.70a2ecd48a1ad01d4c04c3404832e2c9.jpg

    The streak on the right is from a star off frame to the north. I'm posting now as the clear sky slots that had been forecast have disappeared, and I have no idea whether or when I will be able to get data to fill in the blanks.

    • Like 10
  5. Although not an observer as such, so can't advise on specific eyepieces, I do just enough visual with bins to have my optician provide me with a set of non-varifocal distance glasses, since everything I want to look at is at infinity. I have quite a complex prescription and find that even for casual "just looking around" they provide a sharper view than my varifocals.

    • Like 2
  6. 37 minutes ago, bottletopburly said:

    I suppose you’d have to have an independent report done to nail down the issues and cause and remedy for each issue , which on a Newtonian breaks down to the secondary mirror, holder and spider vane , and primary mirror and primary holder , 14” is big and heavy which makes you wonder if the engineering is up to the job to hold the weight, I suppose you’d have to compare to another large newt manufacturer that you know has good engineering to seek out any weak spots on your scope maybe @Peter Drew may be able to give his thoughts , but certainly for 6k your expecting the best engineering which obviously you haven’t got and customer service seems to be below what you’d expect, but I would expect you will need to spend some more money to modify the primary holder and maybe change the secondary holder and spider vanes , I wish you luck in getting your scope to a better condition maybe talking to other 14odk and see if any of them have managed to correct issues with their scope .

    The ODK isn't a newt, it's a Dall-Kirkham derivative with a three element corrector, and is at a whole different level as regarding complexity, and with opportunities for things to be stuffed up.

    TBH this story is giving me cause for concern, although so far (Touch wood, fingers crossed) my ODK 12 has been giving me good images. I will though check defocused stars for roundness, though what I've seen so far looks OK. Maybe I've just been lucky, though being lucky isn't something I'm familiar with.

    Maybe I should have gone with my first thought of a 12" GSO RC and focal reducer.

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