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Xilman

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Posts posted by Xilman

  1. On 02/06/2022 at 21:10, AstroK said:

    I have an Altair 183C PRO and during this last week appeared what I can only describe as interference patterns.

    Each of my cameras have shown this pattern on (at least one of) flat, dark and bias images. It seems intrinsic to the construction of the camera. Standard pre-processing removes them from the final science images. The image below is a bias from a SBIG-8 in 2x binning mode. It has been heavily stretched to show the fringes and the warm pixels.

    What is curious, to me anyway, is that you have only just noticed them on your kit.

     

     

    bias.png

  2. On 01/06/2022 at 08:11, ollypenrice said:

    Here, even more than in the OP's post, the rings are not only distinguished by brightness but by colour.  Not only that: the colours seem to be organized somewhat like an opened-up white light spectrum. (Or perhaps a sequence of RGB,RGB etc?)

    Some might regard this proposal as heretical but here goes. If it is the only data you have there may be no alternative.

    Three things (at least) are obvious in your image. The rings are coloured, they are wide and they are circular.

    That they are coloured indicates that if you process them, you should treat the R, G and B channels separately: split the image into three, process independently, and recombine at the end.

    That the rings are circular indicates that the two-dimensional Fourier transform of the images will show strong symmetrical structure.

    That the rings are wide indicates that there will be strong structure at low frequencies in the Fourier transform.

    Therefore, try taking the Fourier transform of each image and then zero out all but the strong low-frequency structure. If when you inverse transform the result you end up with broad circles in the same position as the originals, and not much else, you know you have selected the correct Fourier components.  Use that inverse FT image as a flat.

    Completely screws any photometric accuracy and may add other artifacts as well, but it will get rid of the aesthetically displeasing rings.

     

     

  3. 1 minute ago, Astro Noodles said:

    I don't know - you tee it up so a guy can show off his telescope and he tells you to go and look on Wikipedia.

     

    Sigh.  Why should I want to show off a design into which I made no input? The "0.4m" is far more significant than "Dilworth" in my opinion.

    Anyway, if you wish --- www.astropalma.com and http://www.larrosa.ch/astrooptic.htm if you want to find out more about this particular Dilworth.,

  4. An entirely sensible question which deserves a full answer so that others can also observe these sorts of things. For outer satellites of JSUN head over to https://minorplanetcenter.net/iau/NatSats/NaturalSatellites.html

    Select which satellites in which you are interested and enter the date and a range of times around the observation. I used 2021-07-08 00:00 and 10 positions separated by 20 minutes. The site will return the co-ordinates of the satellite at each time.

    Prior to that I plate-solved the image (using a local installation of astrometry.net) and displayed it in an image viewer (ds9 in my case) which indicates the position of the cursor as it moves around.

    Many other ways are possible (rummaging around the JPL web site is valuable, whether or not you want to find satellites, as is using Aladin) but I leave those as an exercise for the reader.

     

    • Like 2
    • Thanks 1
  5. On 02/06/2022 at 11:04, alecras2345 said:

    No i have no setup. it's always cloudy here and there are street lights.    My bedroom window faces south but there are houses all around, i live in a cul de sac.   I don't know what the solution would be to my stargazing problem.   Like i said i want to do it online but i don't know what site to use.     I like reading about the solar system and i was reading the book Planets yesterday and he mentions that Mercury has an elliptical orbit so on one side of the sun it can be very hot but at the other end of its orbit can be very cold.   Brian cox also mentioned that mercury has a spin orbital resinance,  does that mean that mercury spins 3 times for every orbit?   im not sure.     Brian cox also said that venus and mars once had seas and were earth like, but that was when the sun wasn't as hot as it is now .   Something like that.

    Ash 

    I will be amazed if it is ALWAYS cloudy!

    I started out by going into the garden with a pair of binoculars and a pair of eyeballs, sometimes without the binoculars. Naked eye observing can be fun and informative. It is how I became a variable star observer. I estimated the brightness of delta Cephei each clear night and recorded it and the date and time when observed. Some weeks later I plotted the results on graph paper and derived the period of how often it changed. Still have those hand-written observations in a notebook which is pushing fifty years old now.

    • Like 3
  6. On 01/06/2022 at 15:13, alecras2345 said:

    what about the science in books, do i skip it?

    Yup.

    Everyone skips "stuff" they do not understand at first reading. This goes equally for researchers working at the bleeding edge of their field as for complete newbies.

    I have been at both ends of that spectrum and have personal experience of skipping stuff.

    There is always time later to return to stuff you don't understand immediately --- after you have gained experience.

     

     

  7. Who says images of small satellites in the outer solar system can't be artistic?

    This one was taken with my 0.4m Dilworth telescope. A Dilworth uses several relay lenses in the optical train, each of which scatters a very tiny amount of light. Usually the scattered light is completely undetectable but if a very bright object, Saturn in this case, is just outside the field of view effects like this can be produced when contrast is enhanced. Saturn was about a million times brighter than its satellite Phoebe, which is marked with the cross lines. Phoebe was magnitude 16.6 at the time of observation, 2021-07-08.

     

    phoebe.png

    • Like 6
  8. Thanks for providing that RAR. It is indeed identical to the one already on the TCS.  Nonetheless, I ran register.bat in an administrator mode CMD; it successfully installed the DLL. The registry entry was already present from an earlier attempt but I verified that it was as specified in the README.txt file.

    What is NOT in the README is that one must double-click the LazyFocus.reg file to install extra gubbins in the registry. Once I did that, MaximDL could see the driver!  The SkyX had to be set to use an ASCOM Focus driver and then LazyFocus. Again, it works (though not in TheSky X 64-bit, unsurprisingly).

     

    Thank you very much for your assisstance. Much appreciated. AFAIK I can now start doing astronomy again.

     

    Pal

     

  9. 4 hours ago, Dr_Ju_ju said:

    can you connect the hard drive from the old computer to your new one ??  if so it may be possible to copy over the missing dll, register it, then see if it works ....

    BTDT, failed miserably. 8-(

    A chap at the BAA (britastro.org) has told me of an alternative.  I will try it out and report back.

  10. My old Win 7 box has died. It used lazyfocus.dll to drive the motorized focusser.

    The new box has Win 10 Pro and most everything (TheSky, MaximDL, LesveDome, SX cameras, etc) now works after some re-installation and re-configuration.

    The focusser steadfastly refuses to be driven by software. The Moonlite PRO ASCOM driver supposedly works as a LazyFocus driver but doesn't. Everything I have tried so far to install the old DLL has failed.

    Has anyone managed to get LazyFocus to work under Win 10? If so, how?

    Otherwise it looks like new hardware will have to be bought and got working.

    Thanks for any help.

    Paul

     

     

  11. NGC 2340 is the brightest member of a rather nice small cluster of galaxies in Lynx. Most members are either E or S0 with bright condensed nuclei.

    The cluster appears not to be very well known, which is rather a shame in my opinion. It contains  IC 458, 459, 460, 461, 463, 464 and 465 --- the latter also known as NGC 2334. --- as well as a number of fainter members.

    This image was taken 10 minutes before Xmas Day in 2019 with a 810s unfiltered exposure on a 0.4m Dilworth-Relay.

     

     

    IC459.png

    • Like 5
  12. Whereabouts do you live?

    By far the best way of learning about any kind of machinery, in my experience, is to ask someone who knows how to drive one properly to show you how it is done.

    Most everywhere in the UK is within striking distance of a friendly group of amateurs who would be delighted to welcome you into their ranks and to help you out.

  13. Now that JWST is up and on its way to its L2 orbital position, the upper stage of the Ariane launcher that put it there is in a (highly perturbed) solar orbit. We know it will return to the vicinity of the Earth around 2047 but not precisely where and when. Recovering it will be quite tricky without a good prediction from an accurate orbit. This is where amateur astronomers can play a big role.

    All we have to do is image the launcher for as long as possible and measure its position against the background stars as precisely as possible. It is also moving, so you need to record the timing of the images to within a second or so. Finally, because it is so close to the Earth there will be a significant parallax effect so you need to report your geographical position too.

    The object is currently around 16th magnitude. It should remain visible until some time in February, though that depends on scope aperture, sky conditions, exposure length and so on.

    Bill Gray at http://projectpluto.com is coordinating the results. I can likely help out by answering questions you may have.

     

    Paul

     

    • Like 1
  14. Overall suggestion: Science --- the making, measuring, recording and publishing observations of value to future astronomers.

    Topics include:

    1. Photometry: variable stars, asteroids, comets, exoplanets, AGN (i.e. quasars, etc);
    2. Astrometry: asteroids, comets, double stars;
    3. Spectroscopy: solar, variable stars, AGN;
    4. Discovery: deep-sky imaging followed by careful examination  to seek for newcomers.

    Enough there for at least a year solid though of course, it should be spread over several years.

    • Like 2
  15. 19 hours ago, John said:

    I feel this is one of the biggest challenges for newcomers to the hobby who do not wish to invest in GOTO mounts. Once the obvious and easy to find targets have been observed and the enthusiasm fired, quite naturally folks want to progress onto slightly more challenging targets but can find this daunting and frustrating.

    I have wondered if we could start a thread or even a sub-section in the observing part of the forum where more experienced observers can post their favorite "star hops" or similar target finding advice, charts etc which can gradually build into a readily accessible resource for those building their experience and widening there observing "repertoire" :icon_scratch:

    I'd certainly be happy to contribute to that (and borrow some as well !) :smiley: 

     

    I would like to try to help, though I've been using GOTO for the last few years. However, most of my astronomy was done by pushing around a Dob or a simple EQ reflector so I have had lots of practice back in the day. Still have a Dob which doesn't get much use. Perhaps I should start practising again.

    • Like 1
  16. 1) Clean the ash out of the observatory.

    2) Refit the camera and get everything working.

    3) Everything else, including tracking down Earth's quasi-satellite Kamo`oalewa  (which will be very hard if even achievable), start measuring VS in M33 and adding more in M31 to the program, imaging a few asteroids named after colleagues, trying for more and/or better images of outer solar system satellites, a few more extragalactic GCs and the regular program of VS and exoplanets.

    Should keep me busy.

  17. On 24/12/2021 at 10:22, andrew s said:

    Maybe worth a try?

    https://arxiv.org/abs/2112.12673

    Daylight Photometry of Bright Stars -- Observations of Betelgeuse at Solar Conjunction

    Regards Andrew 

    I'm tempted.

    I have managed to image a 12th magnitude star with a 2-second exposure through a Sloan i' filter only 36 minutes after sunset. Not measurable and no comparisons in the FOV, other than Venus and Neptune, the conjunction of which was the point of taking the image.

    Most everything brighter than, perhaps, 10th magnitude, should be measurable in full daylight with a little care.  I can manage 19th after dark.

    • Like 1
  18. 9 hours ago, Rodd said:

    Could be an accident. It might be a blob coincidentally in the right spot

    Given that the other blobs in the image which are of similar intensity can all be matched up with stars and background galaxies visible in the likes of SDSS and POSS2, it would have to be a most remarkable coincidence.

    I went to quite a lot of care with the analysis of that image.

    • Like 1
  19. 3 minutes ago, Xilman said:

    I do not have a 4" scope and so am unable to satisfy your request. Perhaps others here could do so.

    Actually, my guide scope is a 100mm refractor fitted with a SX Lodestar2, so I was lying ---- or, to be charitable, deluded.

    I may give it a try when I return to La Palma in the spring. I see no particular reason why a few hundred 10ms exposures should not show the companion in a few images. The separation should be several pxels (more if I fit a Barlow) and Sirius B is so bright it would be an easy binocular object if it were further from Sirius A.

     

     

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