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Showing content with the highest reputation on 25/01/19 in Posts

  1. 13 points
    Hi everyone I saw a cheap 'Russian' -it says USSR on the lens ring- 300mm lens on eBay for €50. Just for curiosity I took this snap, never expecting anything like. I was surprised at the colour and corner correction it gave. It would be a great way to make a start in ap with a dslr; my Canon kit lens comes nowhere close. Interesting... 700d: 90 minutes @ ISO800
  2. 9 points
    This is one of my favorite regions of the moon, every time i keep imaging this region over and over again. This is an old image was taken last year.
  3. 8 points
    Heya, It was raining all morning with total cloud cover. Went to town and ran errands instead. But, to my surprise, around noon, the sky cleared up and seeing was pretty good. Managed to get some data on AR2733, it's starting to calm down and the umbra are fading, but the plage is still large and there's activity going on. There's some rather nice prominences around the limb, but one particularly interesting one making a show. B&W: Color: 150mm F8 Refractor Daystar Quark Chromosphere & PST Etalon ASI174MM + 0.5x Focal Reducer Very best,
  4. 6 points
    Have you ever wondered what a hi-resolution image of a volatile star like the red super-giant star Betelgeuse looks like? Well you don't have to wonder anymore...here you go...> https://www.inverse.com/article/33408-supergiant-star-betelgeuse-is-bulging Your comments are welcome.... P.S. For those who thought Betelgeuse was big...then check this star out...> https://upload.wikimedia.org/wikipedia/commons/f/fe/Sun_and_VY_Canis_Majoris.svg Klitwo
  5. 4 points
    I would class this as transportable. Portable , to me, suggests being able to carry the telescope complete. ?
  6. 3 points
    I suspect related to good transparency as much as anything else perhaps John?
  7. 3 points
    Confirms my thoughts that this must be the best and friendliest forum ever. Well done to all above for their thoughtfulness that is often so lacking in today's society ? Steve
  8. 3 points
    Hi Richard such a kind offer. My sessions are so time limited (usually an hour or so after school) that I'd probably not make best use of it and tend to use star maps with them like road maps. Let someone else benefit from your kindness this time and thank you again ?
  9. 2 points
    At around 7am, the waning crescent Moon will be at 14 degrees above the horizon and between Venus and Jupiter. Given some clear skies, this should make quite a spectacle. The 25 day old moon will be 17.8% illuminated, and about 4 degrees from Jupiter and 4.5 degrees from Venus. Well worth a look in binos or a widefield photo opportunity. View the calendar event
  10. 2 points
    I guess I would be totally out of imaging at the moment if I didn´t have my 3 nm Astrodon Ha-filter. First clear nights in over 2 months and of course that darn evil orb is up there, bright as ever! ? Managed to get a total of 76*5 minutes and I guess this is about as good as I can get it considering the full moon. Really can´t wait to get my hands on some O3 and S2 data for this one now! Oh, if only I could afford Astrodons for those as well... The field of view of my Sigma 500mm lens really fits this target! Thanks for watching, hope you like it ? Gear used: ZWO ASI1600MM-Cool @-20C Astrodon 3nm Ha filter Sigma 500/4,5 EX DG HSM tele lens ZWO EF lens adapter ZWO EFW-8 filter wheel Orion Magnificent Mini Autoguider Skywatcher HEQ5 Pro Synscan
  11. 2 points
    Kronos831 : replied back. Perfectly understandable for you being cautious. Rest assured, only true intentions. It is a part of the hobby to spread the knowledge and equipment. Hope you can do the same in 20 years time Will pack it up and hope you receive it quickly!
  12. 2 points
    I've made 100's using human hair and have the bald patch to prove it. ?
  13. 2 points
    One interesting aspect of observing faint objects is that they are often so easy to detect after you see them the first time. In my experience, the nebulosity around M45 has always proved impossible. That said, the comment from Burnham above is perhaps important as I generally observe from dark skies with my 16" dob. The only time I felt I was 'seeing something' was with a 100mm f7 ED frac from the same site. Maybe I was! I'll certainly return to this object on a regular basis anyway as it's so lovely.
  14. 2 points
    Well done mate, you can't even tell there's a Sun up there here. Dave
  15. 2 points
    I can't remember exactly, but you list does look right - there are three distinct types: small ones that go on worm shaft, large ones that go on main shafts (RA and DEC) and conical one that goes on dec where CW shaft extends. I just took mine with me, went to local shop - showed them to the guy and said "I want the best ones like these" - he gave me bunch of SKFs Further "mods" that you could consider would be better tripod (if not pier mounted) and saddle plate. There is one "trick" you might want to try also - but involves just settings. DEC axis can have different amounts of backlash depending where on "circle" you are checking - and if you remove backlash where there is plenty - you will get stiff motion on opposite side. If you adjust where is little backlash you might still get some backlash on other side. If this happens - you can actually determine range of DEC motion that you are likely to use with your mount - you are likely to go below equator on south side, but you are not likely to hit anything close to horizon on north side, so it is likely that DEC won't do full 360 rotation in use (it might do even less if part of sky is not accessible from your location). Place problematic part of DEC where it will not be used by turning it either by hand (worm wheel when mount motor cover is off) or in EQMod - by slewing to that position and then resetting motor position to home (not parking to home but resetting to home - if you have done PEC, make sure you don't do slew in RA - keep it as is - in home position). Return scope to home by undoing clutches.
  16. 1 point
    Couple of ways to go about it, and I believe it's been discussed before. You can either measure average FWHM in your exposures, or calculate it (approximate would be better term). Approximation of star FWHM would be based on couple of parameters: seeing FWHM that is likely for your location, or if you want to have optimum resolution for those special moments - go with best likely seeing FWHM, take Gaussian approximation to Airy disk for your optics, take guiding RMS and pixel size - and convolve all of that and measure FWHM / sigma of resulting gaussian (or you can approximate each by gaussian and do square root sum squared on corresponding sigma). Either way you get FWHM/sigma of gaussian approximation for PSF (either measured or estimated). Do Fourier transform on it - result will be another Gaussian (take squared value since we want power of it, or conjugate times complex number, or magnitude of complex number), and then you can choose threshold value (let's say 5% but you can choose 1% if you want to try to do frequency restoration) and select frequency that has been attenuated by this threshold value (for which value of frequency on X axis is the Gaussian 0.05 or less?). This frequency will determine your sampling rate via Nyquist - you need twice number of samples corresponding to that frequency (want to capture that frequency and all smaller frequencies than that one). Simple, right?
  17. 1 point
    Have it on my dob as well - made quite of difference.
  18. 1 point
    That’s because it is compatible with the ASI120 Mini The ‘mini’ cameras whilst USB2.0 use the new drivers and chipsets and do work fine on the ASIair, it’s only the older generation of USB2.0 cameras that don’t work with the ASIair - all cameras currently for sale will work just fine.
  19. 1 point
    The versions you link to above, the ota is the same in all cases, the difference being the mount (and a different paint job ) I personally went for an AZ GTI mount and found it a good combination for portability. Similar wifi capability like the Astro-fi. Again the choice really depends what you want to do. The eq mount would be much more suited to long exposure Astro photography the alt-Az good for visual ergonomics and even planetary imaging
  20. 1 point
    HI, sorry for the late reply. I'm using the orion 50mm guidescope with my ZWO 120MC colour camera. Tracking is OK, about 1 to 1.5 arc seconds . Used to be better, my AVX is getting old.
  21. 1 point
    I believe that what you intend to use it for will determine the best choice. The advantage of the C5 over small frac is effective aperture (which for the C5 is 117.5mm). It also has the advantage as you suggest of short length at 30mm and low weight (3kg). Oh and no chromatic abberation For deep sky (both visual and imaging), disadvatages are long focal length. But assuming you use a focal reducer to compensate this your next limits are restricted FOV (vignetting) and spherical aberration. For planetary the disadvantage is having the central obstruction which will reduce the relative peak diffraction intensity - effectively reducing contrast I think its really hard to find a refractor that beats the C5 for all portable needs - if I had unlimited budget I think the Borg 90FL would be a great comparison to make Borg 101ed would be my next choice but length of OTA increases to 55mm, but can be broken up into smaller peices for travel
  22. 1 point
  23. 1 point
    Sounds likely Stu. My skies vary a lot here from the practically opaque to the quite transparent. Sometimes over the course of just a few hours.
  24. 1 point
    A timely reminder. I already had it on my calendar, but it was useful to have the reminder as I don't look at it every day! Thanks for posting
  25. 1 point
    That, and the silver knob, just above it.. The 2 grub screws either side, even out tilt.
  26. 1 point
    The sharpest I've tried have been Zeiss Victory. They were sharper and more contrasty than my Leica Trinovids. However, I'm not sure that I preferred them. I found the view a little stark and less natural than that in the Leicas. I've never tried Swaros but would like to do so. Olly
  27. 1 point
    Well done getting those Charl. Little hope of getting anything here today
  28. 1 point
    Congratulations on grabbing anything Charl, is wall to wall cloud here. I really enjoy your posting, keep them coming.
  29. 1 point
    Hi, If you are guiding using PHD2 you can use this app: https://openphdguiding.org/phd2-dither-app/ That's assuming your mount is capable of being guided. If you tell us what your mount, telescope and camera are we'll be able to offer some suggestions.
  30. 1 point
    So here you have, the PCB and schematic files for Arduheater !
  31. 1 point
  32. 1 point
    I have the SW AZ EQ6 GT and it handles my 10” Meade SCT OTA with ease. Love the fact that I’m seconds you have a solid AZ Goto as well if you’re just doing a quick bit of visual. Pretty bombproof thing and stick on the SW SynScan WiFi adapter and it’s a joy to use.
  33. 1 point
    I've gone for a Celestron 127 Mak Goto package because it comes with a steel tripod and software so I can control things from my tablet. The Sky-Watcher only offers an alloy tripod. I've also ordered a Meade Series 4000 zoom lens and am keeping my fingers crossed that the price will not blow the budget my daughter has set for my birthday. Thanks again to everyone who participated in responding to my plea for help.
  34. 1 point
    Looks about right to me, don't see any problem with rubber sealed bearings. Don't over tighten the taper rollers, they should run smooth with no play when you rock or pull on the shaft. Watch the endfloat on the tiny worm bearings, again run smooth with no pinching and no rock in the shaft. Take your time adjusting the backlash in each worm Some of the old 6006 bearings on mine were really rough from new, glad I did the overhaul. It's a great mount when the bearings are done and the Rowan mod is complete.
  35. 1 point
    You can install Astronomy Linux 18.04 with your name and password.
  36. 1 point
    Yes. ================== Login: astronom Password: 12341234 ================== You can change the default password in menu: Applications -> System Tools -> System Setting -> User Accounts
  37. 1 point
    My friend Gerry! Any of the 3 cameras that you buy will perform well with a C8: ASI 224 + barlow 2X, ASI 290 without barlow or even ASI 174 with a Barlow 2X or 3X will give excellent results. I personally will get rid of this AR 152 to get a C9.25, in fact I bought it with the intention of making solar, but I already realized that this is not my beach, apart from the fact that, to make high resolution solar, I will still need more accessories that are expensive and difficult to get here in Brazil. I want a lot in the near future to get an ASI 174 mono, not to make colored photos using filters wheel, but to make polka dots taking advantage of 100% of the pixel in the IR Pass with C9,25 and C14 as well as to image the planets at specific wavelengths such as UV, IR 742, IR 850 and even in Methano. Note that in a color camera, you never take 100% of the pixels that are working at only a certain wavelength. In the above photo made with that set, I used only 50% of the camera pixel.
  38. 1 point
    Welcome to SGL, Around a decade ago FLO ran a discount scheme for SGL members. It lasted a year or so. Margins are slimmer these days so we focus instead on competitive prices available to all. What he said ^ ? We do still post occasional promos or 'special purchase' offers here at SGL. Also, when we last updated our website we added a Price Match Promise to ensure we remain competitive. HTH, Steve
  39. 1 point
    I compared the 22mm NT4 on the Orion complex against the 17mm ES-92, 24mm APM UFF, 27mm Panoptic, 30mm APM UFF, 35mm Baader Scopos Extreme, and 22mm AT AF70 in my field flattened AT72ED. The biggest surprise was that it was the most difficult to get it to snap to focus of the 7 eyepieces. It was sharply focused when that point was found, but the out of focus stars were spiky rather than fuzzy as in the rest. That, and I had to refocus for the edge indicating field curvature. Despite refocusing, there was really noticeable astigmatism (not subtle at all). I really couldn't take in any more TFOV with the 22mm NT4 than with the 17mm ES-92 due to the lack of usable eye relief. Stars were also much sharper to the edge without no refocusing needed in the ES-92. Win definitely went to the ES-92 in that head to head despite the two costing within $30 of each other new here in the states. The 24mm APM UFF had a much more pleasingly sharp image across the entire field despite having a narrower AFOV. Again, it didn't give up much TFOV to the NT4 due to the latter's lack of usable eye relief. For a 1.25" eyepiece, it held its own surprisingly well. The 27mm Panoptic had almost exactly the same TFOV and for once, it had the better eye relief, so it appeared to show more field than the NT4. I could just take in the entire field without pushing my glasses into my face. Again, the field was sharper edge to edge without refocusing in the Panoptic. The AFOV just feels narrow at 68 degrees. The 30mm APM UFF showed way more TFOV than the NT4 or Panoptic, was sharp to the edge, and easy to take in with eyeglasses. Definitely a growing favorite of mine. The 35mm Scopos is incredibly sharp and constrasty in the center 75% of the field of view, possibly more so than the 30mm APM UFF. It is difficult to see the last 20% without tipping your head to align ones eyeglasses properly to avoid inducing astigmatism into those edge stars. However, it was splitting the Trapezium into 3 bright stars at 12x all the way to the edge once properly aligned. The 30mm APM UFF was close without any contortions. The biggest downfall to this eyepiece is the 64 degree AFOV which feels very narrow in comparison to most of this field of eyepieces. The 22mm AF70 was no worse astigmatism wise relative to the NT4. It seemed just as sharp in focus and had a much flatter field than the NT4. The NT4 was showing more field without pressing my eyeglasses into my face, so it might have the win here. I'm still undecided and will have to try each out in the Dob with the coma corrector. Overall, I was bit underwhelmed by the 22mm NT4. I was expecting to be blown away by TV perfection equaling the ES-92, but was instead treated to difficult focus, astigmatism growing from 70% out to unacceptable levels by the edge, and noticeable field curvature. It was better at controlling edge of field brightening than the AF70, but it also costs 4.5 times as much. However, the ES-92 had near next to no EOFB at all. The Orion nebula was distinct and separated from the background to the edge whereas it faded away in the NT4. I'll hang onto the 22mm NT4 for now and keep comparing it to see if it grows on me.
  40. 1 point
    I have a pair of Vixen (Japan) B type 20 x 80s which are superb and from what i can gather quite rare..... Alan
  41. 1 point
    There's always one.....I'm actually from the UK. Moved to Australia 16 yrs ago. The view of the Milkyway is quite spectacular from the southern hemisphere.
  42. 1 point
    I hardly know where to begin. There's the small and large magellanic clouds, eta Carinae nebula, coal sack, tarantula nebula, omega centauri, 47 Tuc, Jewel Box.
  43. 1 point
    In the absence of any definite answers I'd say as it's designed for F6 it will be fine, might have to do some trial and error on spacing though
  44. 1 point
    Welcome could you rotate your photos they’re upside down ???
  45. 1 point
    A couple weeks back but did have a go at Wirtenan in the fog with Capella. Christmas Eve shrouded in swirling fog oh and Moon was 98%. Still with the weather like it was can't be fussy so setup anyway, this time using the 85mm f1.8 Canon lens at f4 on 1100d with a flocked flower pot shield. Using a Virtuoso mount and Android tablet rattled off 110 lights of 30 seconds ISO 400, 24 flats , 23 dark flats and 23 darks and bias files. Stacked in DSS using the best placed image for the comet rather then the highest scoring light made a stack on the stars and one on the stars and comet, comet only did not work due to the lack of clear sky around the comet. The processing was in StarTools with a mix of layers and masks. I have tried to keep more star data in this process rather then isolate away the background too strongly. The fog did make the data a bit more murky then i had hoped for especially with 110 light frames, took quite a while marking the comet on every frame. I reprocessed having another go again using StarTools I created three images. Stars stack for the stars and then healed out the comet area. Stars and comet stack for the comet and subtracted the stars using layers and then used the life module do subdue the stars and then the heal module to remove Capella area. Then worked on the colour in the comet and lastly combined the files again using layers module. I am currently trying to create a time lapse of 11 images from DSS each stack having 10 images with the reference file starting with the first then advancing 11 frames before the next batch's reference frame ending with the last frame ending as the last reference frame in the last batch. But these batches are hard to process as the fog and cloud are much more evident. Work in progress. Thought to share the effort here as well as the challenge.
  46. 1 point
    Welcome to SGL. Very nice first shots
  47. 1 point
    Persevered and got 5 short subs between the clouds and gusts of wind, no calibration as you can see Dave
  48. 1 point
    Yes you should aim for 0.5" Total RMS for that kind of resolution. If you can't achieve such guiding, then bin your DSLR images. It can't do hardware bin, but in software it is easily done. If you want to go for lower resolution, first thing that you can do is use super pixel mode for debayering - that will be very similar to x2 bin - since you are using OSC camera that is even better than to debayer and then bin x2 in software. Btw, 0.5" RMS is achievable on tuned and belt modded HEQ5, but with such small guide scope, you are lacking star position measurement precision to be certain that you are guiding that good. With only 227mm FL (if I'm right about your guide scope) and 3.75um pixel camera, your guide resolution will be ~3.41"/pixel. About 1/16th - 1/20th of that will be measurement error in star position - and that is 0.17"-0.2". You probably need your guide RMS to be at least 3 times that to be able to measure it correctly - 0.5" is at bottom limit of "precision". This does not mean that you won't be able to guide at 0.5" RMS, it just means that if PHD2 is telling you that you are guiding at 0.5" RMS (or other low value) - that might not be quite correct - it might in fact be a bit less or a bit more than that. I've found that sometimes you can go lower than 0.5" RMS with HEQ5 but such nights require best of conditions - absolutely no wind, and steady atmosphere. Here is my "personal best":
  49. 1 point
    Mmm, yes I see what you mean. I use the Oculus camera and that has an electronic shutter, so nothing covering the chip, and it has been operating perfectly outside for over a year now. So, I conclude that you have absolutely nothing to worry about! Or should I now be worrying...?!
  50. 1 point
    No worries, I tend sometimes to take a while to respond because I receive no notifications from this forum (?), I'm also available @jbrazio. I never really shown my custom take on dew strips.. so here it go, the BOM for it is: 3D printed template Kanthal Resistance Wire 24AWG Kapton tape GX12-4 male & female connectors Wire & heat shrink tubing
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