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AltAzAstro

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Posts posted by AltAzAstro

  1. Excellent image, can't help but praise and congratulate.

    Do you know what is the magnitude of the small galaxy that can be barely perceived as an elongated disk on the right of M81 and a bit to the bottom?

    I could not find it of any of my planetarium apps ... hence I guess it is pretty dim ... 15-16?

     

    ADD-ON

    By the way, I now notice there is another one, even slightly fainter on the other side of M81, almost symmetrical to the first.

    • Like 1
  2. Hi all,

    as it can be derived from my nickname, I am a fan and supporter of altazimuth DSO imaging. I take pictures from the balcony of my flat in downtown Turin, Italy.

    Turin is the fourth biggest city in Italy and of course IL is an issue. According to Clear Outside mine is a Bortle 9, 17.6-17.8 sqm sky.

    I also have to deal with the "proximity IL" of the illumination of the internal court of my building.

    So the border conditions, to use a mathematical expression, are far from optimal, quite the opposite.

    Nevertheless I am quite satisfied of the results I was able to obtain so far with my AZ-GTi and my small scopes and camera lens.

    I have created my own site advocating for altazimuth DSO imaging, where I described all of my equipment.

    Basically so far my scopes are two short refractors, the ubiquitous 80/400 and a rarer Bresser 102/460, and two catadioptric ones, a mainstream SW MAK-90 and a less known Meade 2045D.

    Recently I have realized than, when paired with a cheap 0.5x focal reducer (mine is branded Telescope Service, but I reckon they are all based on the same design), produces surprisingly good results.

    The two pictures I'm showing here, which are my latest so far, have been indeed realized with the MAK-90 and the aforementioned focal reducer, even if the effective reduction is rather like 0.56-0.57, for a focal length around 710 mm and an overall focal ratio of about 7.8 .

    M81 is a stack of 126 20s exposures, and M51 a stack of 140 20s exposures, all taken with a ZWO ASI 178MM.

    The images were acquired with Nebulosity 4.2, stacked with Astro Pixel Processor and post-processed with StarTools.

     

    M81-20190523-126x20s-720mm.thumb.jpg.bb8f18039e4c6741c854dbb196860f4a.jpg

     

    M51-20190524-140x20s-720mm.thumb.jpg.03510e84846f63579d19986a92dd4754.jpg

     

    • Like 5
  3. Thanks again for the kind words 🙂

    @Marvin

    Yes tourist place can be very expensive, particularly bars, restaurant and the like around them ... sometimes bordering on swindle ...

  4. A stack of 101x30s lights taken with a SW MAK 90 plus TS 0.5x focal reducer and a ZWO ASI 178 MM mounted on a SW AZ-GTi in altaz mode.

    The real reduction factor of the focal reducer on this setup is indeed 0.57x, for a focal length of about 712 mm, with some tolerance.

    Taken from the balcony of a flat in downtown Turin, Italy (17.8 sqm).

    NGC4565-20190510-MAK90.thumb.jpg.5dbeef003a51831e94e66445c2ae726d.jpg

     

     

    • Like 11
  5. I got this with StarTools:

    M51-SGL.jpg.3bcae0988db2683631cf04e34df7ec22.jpg

     

    In black and white is even better (residual gradient can be reduced even more):

     

    M51-SGL-BW.jpg.c9722edb2f019b2e1f138e4b069c75d7.jpg

    My workflow was:

    Autodev -> Wipe -> Autodev -> Crop ->Deconvolution -> Color -> Life (Less=More 75%) -> Life (Isolate 75%) ->Bin 50% -> Contrast 75% -> Stop Tracking Final Noise Reduction -> Sharp (Large 25%) -> Contrast 75%.

    BTW, very heavy gradient: I image from the balcony in downtown Turin, which is a 900K inhabitants city, and I never got such a nasty one. Maybe you could try to shield the scope with some cardboard divider or something like that.

    • Like 2
  6. Moon on May 13th 2019, approximately at 10 PM UTC.

    This image was taken with a Bresser AR 102-XS short achro mounted on a SW AZ-GTi, using a "semi-narrow" bandwith filter about 35 nm wide (642-677nm) obtained by cascading a Baader Fringe-Killer and an Astronomik ProPlanet IR 642 filter in front of a ZWO ASI 178 MM camera.

    The focal length is the native one of the scope, namely 460 mm, and the image is the sum of 431 frames processed by Autostakkert 2, wavelet filtering with Registax 6 and deconvolution with StarTools.

    I think it proves that, when working with a limited range of light frequencies, the fast achromat can nevertheless produce decent lunar images.

    Moon-20190513-431f-460.jpg

    • Like 4
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