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szymon

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Posts posted by szymon

  1. Oh interesting, I'm surprised to hear that.  Avalon claim that the EQ6 is the root of all evil and that's why they moved away from it to StarGo!  Do ask if he'd be interested in selling (although I've just had to pay a yucky tax bill so money right now just isn't available, but I'd be interested in knowing if it'd be an option..).

  2. 3 minutes ago, ollypenrice said:

    The mount simply stopped responding to slew commands, whether from the PC or from any of 3 handsets. A change of motherboard made no difference.

    It has been sitting in the house for 9 months waiting for me to drum up the will to sort it out and... now it works. I'm trying to feel pleased about this but exasperation is winning so far!

    Crazy.  Is yours the older EQ6 motherboard like mine or the newer StarGo board?  (And if the latter does that mean you have a spare ? 😉).

  3. Update: I've been doing some digging and I now understand things are meant to work with this scope.

    Here is what you will get with the scope without any reducer (it's naturally flat, due to the built-in flattener😞

    image.png.cd33c3cc7c93c7542eb6cd84e2e34a3f.png

    This matches up with my experience -- the stars in the corner at APS-C are nice and round, and it works pretty well for galaxies at f/8.  Yaaay.

    Now, with the reducer I have, 0.7x which gives me f/5.6, the stars in the far corner look pretty odd when you go in close up:

    image.png.9018232e53a0ada52b825071cf00c7f8.png

    and indeed that's been my experience.  However, as evidenced by my soul nebula above, they do round off nicely in stacking (and it's only in the extreme corners).

    Finally, there is another reducer available, 0.77x which gives me f/6.16, which should in theory give better results in the corners for APS-C:

    image.png.7967647ea63548bc2e47f4bb8e347dd7.png

    In fact, this reducer looks like the stars wouldn't be "too bad" in full frame even (based on how my APS-C stars round off with the other reducer).

    For now, I think I can live with the 0.7x and deal with the stars in the extreme corners; as mentioned they do seem to 'round off' in processing.  If the 0.77x turns up for sale inexpensively somewhere in future I might get one, but it's not vital imho.

    -simon

  4. On 10/12/2020 at 09:49, Roberto Coleschi said:

    Well, another Vixen AX103s user. Maybe there aren't many of these telescopes, but I like mine very much. I will tell you that the #37228 reducer does not flat the field perfectly also in the APS-C cameras, also in my QHY 163m (same as your 1600mm) The new VX-37247 0,77 x  works a lot better: perfect stars at the corners due a different optical project.

    Thanks a lot for your experience Simon, clear skies 🙂

     

    Here a  full res test with the new HD reducer:

    https://www.astrobin.com/full/kxnhjy/0/

    So, with my ASI1600 I did manage to get perfect round stars in the  corners using the #37228 0.7x reducer (using a Gerd Neumann CTU to adjust for tilt).  However I have now moved up to an APS-C IMX571 camera (the Altair 26M) and it is indeed impossible to get perfectly round corner stars with it, no matter what distance I have from sensor to reducer.  Without the reducer at f/8 I get a perfectly flat field, so it’s just the reducer which is not capable of properly handling APS-C — which is disappointing, because it’s sold specifically as an APS-C capable imaging scope!

    Do you have any sample images with an IMX571 camera and the new HD reducer by any chance?  It might be worth me investing in it — it’s currently galaxy season and the 825mm f/8 actually works surprisingly well from Light Polluted London (bortle 8, 18.25 SQM on a good day).  However longer term I think I can live with f/6.16 and 635mm if I know for sure that I can get good corner stars 🙂

    It’s actually not *that* bad with the 0.7x — I may just live with it as the stars do round off a little in stacking (a couple of my sample images attached — soul with the reducer, bode’s/cigar without) but it’s going to bug me...

    68730880-9E23-4B85-A042-AF60E6B82B65.png

    56186EF8-6569-4D91-9BA7-6AD3C6AAF112.png

    • Like 1
  5. This has always been one of my favourite nebulae -- I have a thing for dragons (the fighting dragons are my favourite in the southern skies).  Since I image from Bortle 8 LPLondon, I wasn't sure whether I'd be able to do justice to this very faint nebula; there is no signal whatsoever on my individual subs!  Nonetheless I am not displeased with the results.

    This image was taken with a new setup for me, and it does have some obvious defects.  First off, the corner stars are a mess -- I have tilt and spacing issues, and I am waiting on some adapters to arrive so that I can fix them, so this is a "best efforts" spacing only 🙂.  In addition, when taking this image I didn't yet have my DeepSkyDad AF3 set up on the Vixen, so I was focusing by hand with a Bhatinov mask.  The focus seemed to hold pretty well (I had heard horror stories of Vixen focusers but the one on my quad seems to be very good indeed), but I'm sure it could have been tighter (I usually set up an AF run if HFR increases by 10%).

    I do feel that my processing lets me down somewhat.  The final edit I chose brings the Ha and Sii into the Red channel at around the correct frequencies and uses the stars from the RGB frames.  My original idea was to just go with a duo-band Ha/Sii presentation, but it didn't really have the depth that I wanted, so I grabbed some RGB in order to get the star colours.  I will probably go back to the data at some future point and process it again.

    Total of 32 hours exposure:
    • 240 x 300s Ha
    • 90 x 300s Sii
    • 18 x 300s R,G,B

    Hardware:
    • ZWO ASI1600MM-Cool
    • Vixen AX103S Quad
    • Vixen 0.7x Reducer
    • ZWO EFW3 Filter Wheel
    • Antlia 36mm 3.5nm SHO Filters
    • Baader 36mm LRGB Filters
    • SkyWatcher HEQ5 Mount
    • SkyWatcher Evoguide 50ED
    • Altair 290C as Guide Camera

    Software:
    • N.I.N.A. -- Capturing
    • PHD2 -- Guiding
    • ASTAP -- Plate Solving
    • EzSuite — LiveStacking and Processing
    • PixInsight — Final Processing Tweaks

    Red_Final.thumb.png.575b176cb67ea690e49102ee10615cc7.png

    • Like 7
  6. 52 minutes ago, vlaiv said:

    While it goes against what I like about astro imaging - first image of Andromeda galaxy is both technically very demanding and very very nice idea.

    It represents image of M31 with "depth of field" feature - like it was right here on a table and shot in a macro mode.

    Artistically image is very good - as it tells a story about a galaxy in your palm - it shows how a galaxy can be viewed as very small object (needing macro lens to shoot it) - compared to vastness of space.

    This sums up almost exactly my thoughts on the matter.  Perfectly encapsulated.  Yes it's not an 'astrophoto' in the way that we usually understand it, but it really makes it stand out.  I look to the skies to spur my imagination; I am not a scientist, I am an imager; I see the future and the past, civilisation and void, the possibilities of life and the unknown.  That is why I keep my eyes (and cameras) to the sky, and I very much appreciate the winning image.

    • Like 1
  7. 2 hours ago, Adam J said:

    It is interesting isn't it. But for now the Evo FF is not proven, while as I have seen good correction from the Starizona one. I would be inclined to hold off myself. 

    When I saw this I did initially think that I could have saved money and gone with this solution instead of my ASKAR FMA180 but on closer inspection this would not work with my ASI1600MM pro without serious vignetting. 

    Also you cant fit a filter wheel into a 17.5mm backfocus so its dedicated OSC cameras only on that basis. 

    Adam  

    I am thinking future plans for my guide scope and ASI1600MM, along with a TS Optics filter drawer.  The filter drawer is 10mm, and it fits direct to the camera's 6.5mm male M42.  I'm thinking it will work as a very portable light-weight setup, and I don't think it will vignette more than can be handled by flats (28mm imaging circle, 13x10mm sensor).  I will give it a try at some point and if the flats correct the vignetting enough then I'll consider the flattener for megaportable...

  8. Wow, that's nothing at all.  Considering the quality of your gear (although I know very little about CCDs but I assume those are sensitive) perhaps there just really isn't anything, and the HOO images that are out there are just the Ha against background and stars.

  9. 23 minutes ago, Kinch said:

    I have not seen it on the subs that I have so far but 'szymon' reports above that it is there. It must be weaker than the SII....so looks like more than the token few hours of OIII that I had planned is going to be a necessity.

    What I saw in a couple of hours integration was ridiculously faint, to the extent that I wasn't sure that there was anything there at all, but I have seen others post HOO images so I'm basing my assumption on that.  If not then I'll be trying various Sii and Ha combinations (HSS vs SHS vs SSH should give the three main dragon types from DnD, for the other geeks out there ;-)).

  10. I dug out a screenshot of the Ha when I last tried this.  Bear in mind that this was with a fan cooled (not set point, so effectively uncooled) 183M (so tiny little pixels) via an 80mm Celestron 80ED (f/6 with reducer) from Bortle 8 LPLondon, going through an inexpensive 7nm Ha filter.  I think this was two hours, so it's ridiculously faint.

    Definitely going to be my first 'proper' target for the new scope 🙂

    image.thumb.png.1d303d8b5ac8176eaeb750e3cb0d3f94.png

    • Like 2
  11. Very nice indeed -- one of my favourites (I love dragons in the sky -- this and the Southern Hemisphere fighting dragons are the two I like best!).  I took some Ha a while back and intend to go back to it at some point (I am in Bortle 8 so RGB is difficulter).  Your data and framing are wonderful.

    • Thanks 1
  12. I am certain that you have a lot more in that data than the picture you produced shows.  You need to learn to tease it out.  The best advice here is for you to spend some time learning to process your data.  This is where a lot of the skill of astrophotography actually lies.  Anyone can follow instructions to polar align a mount, point a scope at the sky and take images.  But in this day and age of digital imaging, it's what you do with the data you get that matters!

    I'm attaching a photo to encourage you.  The attached image is not great in any way.  There is very little actual exposure time, less than half of what you have.  Worse, this was taken from my back garden, in Light Polluted London -- Bortle 8 on a good day, but there was also a full moon (this was on Saturday).  There were clouds all around, I only had the scope out to work on getting my spacing and tilt correct and then when I gave up on that (you can still see how off it is from the photo) I decided to use M31 as a test image.  I pointed the scope and managed to get 31 minutes of exposure, 7 x 60s L and 4 * 120s each of R, G, B (I am using a ZWO ASI1600-MM Pro with Baader LRGB filters), through thin high clouds before the thicker clouds really came in and made it impossible.  This is way way less data than your image, and I guarantee that the quality of the data is lower, but processing it correctly managed to pull out the following:

    andromeda.thumb.png.6c1ec9aff204b449b214cd0449928fca.png

    Once stacked, my processing steps here in PixInsight were (from memory):

    • On L: DBE, deconvolution, tgvdenoise, mmt for NR, arcsin stretch
    • On each of R, G, B: Multiple levels of DBE (more interested in getting rid of the gradients than preserving detail), arcsin stretch
    • LRGBCombination, histogram stretch, Photometric Colour Calibration, curves for saturation hue and contrast, local histogram equalisation, mmt, mlt

    That's what worked on my data.  It will be different for your OSC data.  You might use different tools, you might stack in a different program, etc -- but whatever you use, I encourage you to keep going, because the data is there, you just need to pull it out!  If there is this much in half an hour in bortle 8, I am absolutely certain that you can get more from over an hour of the same target in bortle 3/4 🙂

    -simon

    • Like 2
  13. If you're getting a good price I would go for it.  The CEM25P is as you say discontinued, but I am sure that it will be supported for a good while yet.  It has a good reputation and it is very lightweight compared to other options.  Also, if you find you want a different mount in future it will be trivial to sell on.  If you're not going to get it please DM me a link so that I can do so 😉

    • Like 2
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