Jump to content



  • Content Count

  • Joined

  • Last visited

  • Days Won


Posts posted by discardedastro

  1. On 11/05/2021 at 17:23, Grant Fribbens said:

    I have had my EQ6-R for a while and started to get issues like you had in PHD2 when I put on my GSO 8" RC. So I have decided to take a look and found that I could feel backlash in both RA and DEC so have tightened this as per the video which was done by Cuiv, The Lazy Geek. Then I also checked the status of the belts and sure enough found that using the hand controller on rate 2 had quite a lot of backlash on the RA belt similar to what this chap, Rosco Bird DEC backlash, had. So I adjusted the belt tension slightly (1/8th of a turn clockwise on the grub screw after loosening the stepper motor screws) and it has made it so much better. 

    That's a great set of videos. Belt tension would make quite a bit of sense and I'll take a look at that for sure - it's about that time of year when I take the whole setup apart and inspect/clean/maintain it all anyway given we're now getting too bright to do anything much with DSOs! I've been doing alright in more recent times - I wonder how much those belts and the whole tensioning setup "walks" with temperature variation.

  2. 22 hours ago, Astro Waves said:

    I hadn't thought about polar alignment helpers but now you mention it I might have a look into that. If it doesn't take much doing then I might see if I can find a tablet to run it on to save weight whilst having to cart everything around each time I need to shoot. 

    If you do the guiding setup right it can also (as @Space Oddities said) act as a polar alignment aid. PHD2 has great tools in this regard - a static polar alignment tool which can get you there or thereabouts, and a drift alignment tool for getting the alt/az set just right. This will actually be more accurate than a Polemaster etc in general though if you're shooting reasonably wide fields you don't need to get that close for long exposures - but if you want to shoot narrowband, it'd definitely be the way to go.

  3. Have you considered tools for polar alignment? Either iPolar if the SGP supports it or a Polemaster.

    You should be able to get better exposure times out of the mount if properly aligned. Guiding won't help much if your PA is spot-on. PHD2 doesn't take much grunt so even a Raspberry Pi would do fine on that front if you wanted to go down that route.

    I'd definitely focus on getting your subframes "good" in terms of duration and stability before considering filters. An Optolong/IDAS LP filter will certainly help somewhat in 7 skies but not as much as longer exposures will!

    • Like 1
  4. Hi,

    Am after a Nexus DSC (ideally Pro version) and/or encoders suitable for same and mounting on a Dobsonian mount.

  5. Hi all,

    So I'm now the proud (and sore - it's heavy!) owner of an OOUK VX16 400mm Dobsonian, and am now learning how to use it and figuring out all the things I need to add on to make it really usable in my environment - but would appreciate some advice from other Dob owners!

    I managed to get a first light tonight - lots of cloud about so it was a bit hit and miss but I managed to collimate fairly well and look at some bright stars. Defocused, tube currents were very, very obvious - I'd kept it outside in a shed for half the day but it was still clearly a bit warm (the back of the mirror measured 5c compared to 0c ground temp on infrared). After about an hour it was down to temperature, but I was struggling with eyepieces dewing up. About half an hour later to warm up the eyepieces, the finderscope was completely dewed over, and both the primary and secondary had a degree of dew on them. The ambient temperature was about 1-2c with humidity around 70-80% by the met office and 50% by my local sensors.

    I also had some issues pointing the scope. I figure a RACI finder and/or Telrad would be worthwhile upgrades - the Explore Scientific RACI finder looks ideal - so will aim to upgrade those. The azimuth bearing seems very tight - it takes a lot of effort to get moving, so fine pointing adjustments are really hard. Thinking I may need to renew some bearing surfaces; I am using a few paving slabs as a base so it's got a fairly flat surface to rest on. Altitude I didn't quite get balanced right so need to shift that around a bit more and then can slacken the brake off.

    I called it a night and put the scope back in the shed - while I can move it around fairly well on the sack truck I bought for it, I'm definitely going to get it a Telegizmos 365 cover so I can leave it set up in situ for longer periods. We're in a fairly damp area - low lying, 25m from a small stream - so suffer quite a bit from dew.


    The mirror cell has a position for a 12V fan which I've now bought from OOUK, which I suspect will help quite a bit with both dewing of the primary and tube currents/cooldown - will fit this once it arrives and see if it helps.


    I'm also thinking that as a beginner in observational astronomy (imaging for a few years now) a digital setting circle is going to help a lot with finding my way around and building up confidence - is the Nexus DSC still the way to go?


    Do I need to consider dew heaters for either the eyepiece/tube, or secondary or primary? What else should I consider for dew control?

    Any tips on things to consider with finderscopes?

    Any other hints and tips for practical accessories for larger Dobs?


    Lots of questions - grateful for any advice!

  6. 5 hours ago, old_eyes said:

    We just need a supercomputer each  - that's all!


    Fugaku 415 PetaFlops

    When I was a young academic, the CDC Cyber 205 could do an amazing 400MFlops. The Intel i3 over 300 GFlops, nearly 1000 times as fast. Ain't progress great?


    It really is 🙂 I came in at the start of the Pentium era, though had a fair bit of time on Amstrad and friends prior, but no coding. i386 was my first chip - we've come a long way!

    If shipping all the image data around wasn't so prohibitive for most people I think there'd be a huge case for a render-farm style service for PixInsight and others; it's bursty, not something all users do all at once, so quite well suited to workload sharing. I did toy with the idea of using an AWS virtual desktop instance for PI (pay by the hour when you need it), but since I did my last PC upgrade I've not needed to consider it. And that's only because I've got a 1Gbps upstream from home, so pushing all the data to the cloud isn't a big deal - easily done in a few minutes for most jobs. Different story for typical rural/semirural ADSL/VDSL/DOCSIS!

  7. 1 minute ago, old_eyes said:

    It's a mix. Calibration and stacking you can leave to computer to get on with it. Noise reduction, even on mono images, is quite time consuming. Building and processing the LRGB image is variable. Some processes are quick, histogram and curves transformation, others take quite some time. With PI it makes the use of Previews to test out what you are going to do very attractive! 'Playing' with the data is a lot harder for big files, and that is the way we seem to be going.

    True. The latest PI release with the quick subframe previewing has helped a lot in my workflow for that sort of thing, particularly noise reduction - but things like TGVDenoise, MureDenoise, and Deconvolution are still very processor intensive with poor previewability (and in the case of deconv particularly a lot of trial and error required on most images).

    • Like 1
  8. Just now, Commanderfish said:

    That hand truck is way cooler than mine!! Looks.like it's extendable too?

    It's actually not quite as good - the platform doesn't extend far enough to fully support the base! It's a 3-in-one so you can lie it down and use it as a platform, and it has some other weird configurations I've not played with yet. 16" is quite a lot to lug around as one person, especially in a very non-flat garden, but I managed to set up a base for it with some spare paving stones and park it in the shed without dropping anything - I think a Telegizmos 365 cover is in this scope's future so it can sit out most of the time.


    28 minutes ago, Neil27 said:

    I was the postman today, collected from a fellow astronomer. Part 2/4 of my imaging rig.

    May I present my beautiful looking Esprit 150, and it definitely is love at first sight!

    Included is the flattener, lakeside focuser, dew heater, flats panel. Aside from a little dust on the front lense it’s perfect.

    That's an absolute beauty. Congratulations - that imaging rig is going to be very sorted!

    • Like 2
  9. 1 minute ago, Dazzyt66 said:

    I'm pretty sure that is the case from watching a couple of tutorials. It doesn't matter to me really as VNC is plenty quick enough even over the wifi - I only want to plate-solve and then start imaging - its not like I'm stacking live or anything - so once the captures are underway I can just leave it going. Its easy enough the next day to move the captures over through wifi even if it does take a bit longer than wired. Suits me fine and I'm loving it all! 😀

    Yep - I normally just have KStars sat on the graph view so I can keep an eye on things. Once I've finished writing this Rust INDI lib I'm hacking away at (or give up and fix some of the pure-Python ones) I do want to hook up a watchdog program that can alert me if imaging or the mount stops - I've had one too many kstars crashes on overnight imaging sessions!

    • Like 1
  10. FWIW, I'd consider myself PixInsight competent/familiar and WBPP confused the hell out of me - it relies on a lot of stuff in filenames etc which is pretty unobvious and the documentation isn't great! I'd strongly recommend starting out with the Inside PixInsight book and/or doing manual processing to get started. It'll be slower and less straightforward but it's a much easier way to learn the software than running straight into WBPP, in my view.

  11. Just now, Dazzyt66 said:

    Yeah, I'm not sure why I'm having a problem, but it occurred to me that even if I save it only on the rpi the FITS image viewer is still gonna get the feed over the connection - which in my case is wifi - so I think having Kstars on the laptop is not going to make any difference (in fact its probably slower) than just using VNC...

    Quite likely, yep. For what it's worth I use KStars on a Pi remotely via VNC and it's plenty quick enough in my experience (I actually run VNC'd into a Pi4 sat in the house which is running KStars, with INDI running on another Pi4 which is strapped to the back of the telescope). This is with everything wired through a good 1Gbps network, though!

    • Like 1
  12. 1 hour ago, old_eyes said:

    I am also using some data from an ASI 6200MM full-frame camera at a remote observatory and those 9576 x 6388 frames are beasts! Start working on a mosaic and you need plenty of coffee breaks.

    Yeah, excellent point - full frame I would argue demands a pretty high-end PC, realistically. Technically so long as you've got a reasonable amount of RAM you can get away with a lot, but practically it's really painful. I've got some images off a Nikon Z6 which is 6048x4024 natively and I think if I were doing an awful lot of that, I'd be looking at something Threadripper based with 64G or more RAM, especially for mosaics! The ASI183MM I'm using today is reasonably high resolution but since it's monochrome the resulting files aren't huge, and once you've got an LRGB master set the processing is generally quick stuff anyway. OSC is a different beast altogether.

  13. 6 minutes ago, Dazzyt66 said:

    Indeed! I am finding it quite easy to use! I easily use Kstars/Ekos using the built in VNC 'Reminna' or via firefox no probs, so its all good there. And its really fast!

    I am struggling to get kstars to work 'locally' on the laptop but with  indi/ekos remotely on the RPI (astroberry) - I can get them to work the mount and navigate fine (so I must've set it up OK), but I want to just capture images only on the rpi  for speed (and then move them later for processing), but for some reason I'm struggling with this - it always wants to find a folder on the laptop not the rpi and wont let me direct to a folder on the rpi - so I guess I'll need to do some youtubing over the next day or so. 👍

    You should be able to set this up on the imaging sequence by selecting upload to remote only and inputting the path there or in the camera settings under the Options tab, at least on recent-ish KStars. If you've got a reasonably fast (wired) network then you'll likely find it doesn't win you that much performance - I think KStars will still pull the image down from the remote end in order to show it and do any analysis (e.g. HFR for automatic focus triggers), so saving it locally isn't a big overhead.

  14. 1 hour ago, JeremyS said:

    Looks brilliant. You’ve got a great scope there.

    Sorry, I have to ask: what’s with the bats and the BBC Club sign? 🤔

    The bats are decorative (we've got pipistrelles living in the outside of the house, so thematically accurate) and the BBC Club sign was rescued from Television Centre before it closed for good 🙂

    Definitely looking forward to first light - which looks like it might be this evening, if I'm lucky!

    • Like 3
    • Thanks 1
  15. Alright, so the postman didn't bring this, I had to go get it myself - but still worth a post I think!

    OOUK VX16 from @Commanderfish now being checked over, tweaked, and roughly collimated after a 2h drive up. Bit of play in the focuser to sort and the mirror cell wants a fan fitting, but otherwise good to go and a superb "little" scope I'm looking forward to trying out!


    • Like 19
  16. If you're on Uist then some friends up the north end of things have good internet - up on Berneray. BT did FTTC to the islands as part of their government-funded builds (though failed to actually connect it up till a few competitors started pointing out they hadn't actually delivered anything to people), but there's also a lot of fixed wireless stuff back to the mainland which is pretty quick!


    Last time I was up there I wasn't really doing astro stuff, but knowing how populous it is (my friend had to go to Lewis to do their driving test because it's the only island with a roundabout) I can believe it's superb! Enjoy while you're there!

    • Like 1
  17. 5 minutes ago, iapa said:

    I have the Logitech Circle cameras - powered of USB and wireless.

    Not particularly cheap - but what is?

    Do they work well in darkness without IR?

    I've got a fair few Reolinks and they're practically useless with their IR switched off, even if the manual exposure is maxed out.

  18. 19 minutes ago, catburglar said:

    Thanks for the suggestion.

    I don't need the GPS, but I can't seem to disable gpsd....if I run 'sudo systemctl stop gpsd.service && sudo systemctl disable gpsd.service' EKOS connects and everything works OK, but after a reboot of the pi I have to do the same thing again- I thought that if I disable gpsd.service it wouldn't come back up after the reboot....

    I'd like to find a way to tell gpsd to ignore /dev/ttyUSB0 - but I can't find a way to do that easily. The only thing I can think of would be to build gpsd from source, but leave out the support for the usb-serial chip (cp210x) that's in cable....but that seems a bit extreme....so I guess I'll just ssh onto the pi and disable it each time I run.

    It's not a massive issue, but it's a bit irritating and I can't seem to find a good way to fix it.


    Try this: sudo systemctl disable gpsd.sock

    To explain a little more - both gpsd.service and gpsd.sock are things provided by gpsd to systemd, which will ensure that all the dependencies for the service/socket are met. That includes, if you just disable the service, bringing it back to ensure the socket is available.

    If it's still booting up then try systemctl list-dependencies --reverse gpsd.service - this will tell you what is dependent on it and bringing it up.

  19. 1 minute ago, old_eyes said:

    I think I am getting the leakage from behind the Atik, when the camera is pointing directly at the security cam. I don't think an IR Cut filter would help.

    But as you say. The way forwards seems to be no IR,

    Ah, around the focuser?

    I did consider that I had some light leakage from a nearby light and packed the gap between tube and focuser base (as mine had some gaps) with Sugru, and the opposing side of the tube is flocked, so maybe that's helping minimise ingress.

  20. Seeing your image there I'm now realising that I'm probably actually seeing the same thing in my imaging. I'd noticed in some geometries - generally lower altitudes - I was picking up a bar across the image. Nowhere near as severe as that, though - it was only when I stacked things I picked it up, and I was able to generally correct it with some careful background correction, but the same basic artifact. I've only had it rarely and it wasn't the end of the world so I hadn't dug into it properly.

    I am using an IR cut filter (mostly just to have a parfocal filter with my RGB) as my L, so all of the filters I'm using are in some way filtering IR, which may explain the reduced intensity.

    I've been toying with the idea of something like the ASI120MM mounted side-on in a box with a Raspberry Pi, though I think these days the Pi high quality camera can also take long exposures and take a variety of fast C-mount lenses. Dropping IR entirely would seem the best approach.

  21. Edit: Interesting, I can't post to this with some content...

    I don't suppose the LX200 will be returning GPS data in a format that gpsd can take advantage of anyway, so I'd disable it.

    If you want a GPS, then USB GPS devices that work with Linux can be had for <£20 on eBay or even Amazon et al. gpsd can be forced to look at a specific serial port and not autodetect with a startup parameter, normally configured in etc default gpsd. Otherwise systemctl disable gpsd would do the trick, so long as you've got an internet connection for time.

    For good time sync, gpsd can do basic clock control but you're much better off configuring ntpd or chrony to treat gpsd as a clock source as they'll do a much better job of regulating your clock. If you get a board-level GPS module or hat you can also configure chrony or ntpd to use the pulse-per-second input from a GPS module to properly discipline the clock, making your Pi a "stratum 1" reference with very good stability for very little money!

    This is probably the easiest solution to achieve that - it's a GPS module hat to drop onto a Pi, but also has an RTC, all the wiring needed for the PPS pin already done, and an external antenna port. The RTC means that even without a GPS fix or internet the Pi can get reasonably-close time quickly.

    Edit: OK, so the forums for some reason block paths like etc default gpsd.conf if you have / in them. Guessing some very overzealous web application firewall...

  22. 55 minutes ago, Hughsie said:

    I recently purchased a Dell Optiplex 790 short form factor (SFF - smaller and more compact) and they are very easy to upgrade. I bought one last year for c£300 via Amazon with an Intel i3 and 8GB of RAM + 500GB spinning hard disk. Now it’s got an i7 installed (£90 off eBay) 16GB Ram and a 500GB SSD (from Crucial UK) plus a 2TB Hybrid SSD hard disk for storage (£50 off eBay). You can get cheaper 790’s on eBay, but sometimes there is no warranty and if something was wrong with the item I would prefer to argue with Amazon to get my £300 back.

    Going second-hand for PC parts can work well but you do need to be very careful - there is an incredible amount of fakes, misrepresentation, and scams on PC parts on eBay. I'd definitely avoid hard disks (SSDs probably fine) on eBay as many will have had a rough life. Even things like RAM are somewhat reliant on people having proper ESD control etc to avoid damage. The scam/fakes side of things is much worse if you're buying relatively new bits, too. GPUs in particular are incredibly sought-after on the second hand market at the moment because of lack of supply (most retailers have waiting lists for the current generation of hardware), so there is a lot of scamming going on.

    Second-hand cases, motherboards, RAM, monitors etc will normally be OK, but for the quiet life I'd always buy new.

    One thing also to consider especially with smaller cases is heat dissipation - higher end parts, particularly CPUs, need large air coolers or water cooling (easily done with all-in-one units which are sealed at the factory) to work fully. They won't die prematurely unless they're really abused, but they'll thermally throttle themselves and slow down if not adequately cooled. AMD recommend a 3-fan watercooling setup as a minimum for a 3950X, for instance.

  23. Very impressive for Bortle 5/6!

    You've got a bit of background which could get cancelled out with some processing, and colours look a bit blueish - suspect this is a side effect of processing to remove sodium glow? You might want to have a play with masks to protect the brighter light sources. But very nicely done. Focus is spot on!

    Hope you don't mind but I had a little play in PI to try and bring out some colour - results attached. The data's really good - I did one which I just did a background subtraction, solved the image, corrected colour balance with PhotometricColorCorrection, and then tweaked saturation with a mask a little. The other I also desaturated and denoised the darker background areas of the image.

    Really good data and lovely framing - got a lot of the little galaxies around M51 in there!



  24. I'll leave the Canon discussion to the experts, but if you're thinking about imaging deep space objects then do consider a dedicated astro camera.

    Secondhand cooled CMOS/CCD cameras can be had for £500 or less sometimes depending on how old a sensor you can tolerate, and will have a much lower noise floor than any DSLR for long exposures. But obviously they're not any use in daytime, so not necessarily the best bang for buck depending on what you want to do! They do also have the advantage of an unfiltered sensor window and easier software control/integration with common software. If you want to do any narrowband imaging then this is pretty key, though you can astro-mod Canons to achieve similar outcomes.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.