Nick James

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  • in reply to: Observatory computer setup #581168
    Nick James
    Participant

    The VPN I currently use is Softether (https://www.softether.org/). I have it running on a hardened Linux box which acts as my border firewall but it will run under pretty much any OS. It is a VPN that operates at the ethernet frame (data-link) layer. It allows you to connect a remote computer to your internal network via the insecure Internet. I have one hardened machine that runs the VPN server and I can then connect through that to the target machine using any protocol that the rules permit (RDP for instance). The observatory PCs are completely isolated from the Internet. I don’t generally allow my observatory or meteor camera PCs to do updates but, as long as I keep my internal network clean, that shouldn’t be a problem.

    in reply to: Observatory computer setup #581164
    Nick James
    Participant

    When something works I don’t like changing it. My main observatory computer is running Win 7 (and CCDSoft and TheSky 6!) but I have one old machine that is still running legacy software on an XP box. All of these machines are firewalled off from the Internet (both inbound and outbound) by my router and even the Win 7 machine no longer auto-updates since MS updates have a horrible habit of breaking things (they broke remote desktop a few months ago on one of the Win 7 machines I do allow to update). I can remote onto the observatory from outside my home network using a VPN. In the vast majority of cases of these “embedded” applications there is no need for internet access. Updates you want, such as orbital elements etc. can be done manually under your control. Even Win 10 doesn’t reboot randomly if it is firewalled off from the MS mother ship.

    in reply to: CMOS Camera for Photometry #581161
    Nick James
    Participant

    The 12-bit quantization and corresponding well-depth isn’t really a problem since CMOS sensors have very low read noise so the normal way of using them is to externally co-add multiple short exposures. This has many advantages over a single long exposure.

    in reply to: Comet Section Meeting on Saturday, May 18 #581137
    Nick James
    Participant

    Finally, around about lunchtime, the processing script finished and the videos are all available here.

    in reply to: Remote observing opportunity? #581136
    Nick James
    Participant

    I’ve been to LP many times and I wouldn’t say that it was that easy to get to. Sites around southern Spain are much better served by frequent easyJet (other low cost airlines are available) flights. This is a consideration when you need to go out to repair something.

    in reply to: Remote observing opportunity? #581135
    Nick James
    Participant

    Kevin’s talk on setting up his remote observatory at your place on LP is here. It’s worth watching to see how much commitment is required to keep things working. I think this is something that the BAA should certainly consider but I’d be interested on thoughts about whether to do it this way or use a fully supported PAYG system such as iTelescope.

    in reply to: Comet Section Meeting on Saturday, May 18 #581128
    Nick James
    Participant

    They are being processed on the website at the moment but it has taken all day to get to talk number 4 and there are 10 of them. It will probably be tomorrow before they are online. You’ll find them on the meetings page here when they are done. Coincidentally I am currently requesting that the BAA WebOps team remove the very slow video transcode that causes the delay.

    in reply to: Videos from the May 29 meeting #581119
    Nick James
    Participant

    I don’t think so. The flashes along the trail look like navigation lights to me. Sputnik 1 was a shiny sphere and so wouldn’t flash in that way. This is the picture I showed in the talk.

    in reply to: Videos from the May 29 meeting #581116
    Nick James
    Participant

    All the videos are now available here. Apologies again for the poor sound quality.

    in reply to: Starlink Satellites #581099
    Nick James
    Participant

    Yes, very variable brightness and separation. I’ve posted a frame from my video here. I’ll put the full video up shortly.

    in reply to: Starlink Satellites #581097
    Nick James
    Participant

    Thanks Paul. I’ll have a look when I get a dull moment.

    in reply to: Starlink Satellites #581096
    Nick James
    Participant

    Had a video running for this evening’s 2130 UTC pass. The sky was bright and cloudy but I recorded 14 of the Starlink spacecraft. I was using a Sony A7s with an 85mm lens at f/1.4, 1/25s, ISO20000 pointed just left of Spica. The first one came along at the time predicted but the rest were strung out over around 3.5 mins. Limiting mag of the video was around 7.5. The spacecraft were all around mag 5.5.

    in reply to: Starlink Satellites #581082
    Nick James
    Participant

    I’m suprised by that. I use winsorized sigma clipping with dithering for all my stacks since I have planes, helicopters etc. to deal with in addition to satellites and dark frames are never perfect. I’ve never noticed any degradation in the photometric accuracy of my stacks using sigma clip compared to a simple mean. In fact I would have thought that it would be better since you are removing residual hot pixel outliers. As Grant says, it would be interesting to see a reference that discusses this.

    in reply to: Starlink Satellites #581079
    Nick James
    Participant

    Not good from our latitudes in the summer but another reason for imagers to use short subs and sigma clip stacking I guess. Not sure of the effect on surveys like LSST. It will be imaging only after the end of astro twilight and it is at latitude 30S so twilight will be much shorter. I guess someone could calculate the period of time during astro night when 500km high LEOs are illuminated from that site.

    in reply to: Starlink Satellites #581076
    Nick James
    Participant

    Calsky has an amateur generated TLE for the train and will do predictions. Use Spacecom ID 99201. The TLEs are currently over a day old and the orbits will be evolving quite rapidly as each spacecraft uses its ion thruster to move to its operational configuration. The prospect of 12,000 of these things in LEO is indeed a concern for astronomers although there will be long periods when they are not illuminated.

    It was cloudy in Essex last night but John Mason had clear skies for the low pass at 22:16 UTC and didn’t see anything.

    Epoch is 24. May 2019 Starlink Trail

    1 99201U 19894A 19144.95562291 .00000000 00000-0 50000-4 0 02

    2 99201 53.0084 171.3414 0001000 0.0000 72.1720 15.40507866 06

    in reply to: Comet Section Meeting on Saturday, May 18 #581064
    Nick James
    Participant

    I’m pleased to say that video and audio from all of the talks on Saturday appear to have recorded correctly. I should be able to post the videos in the next week or so.

    in reply to: Comet Section Meeting on Saturday, May 18 #581060
    Nick James
    Participant

    If you are coming to the meeting on Saturday by car please see the directions attached. There is limited parking in the school carpark near the venue. Alternatively there is paid parking in Nunnery Lane. York has a number of Park and Rides which may also be an option.

    Hoping to see you there.

    in reply to: Comet Section Meeting on Saturday, May 18 #581059
    Nick James
    Participant

    I hope to have video. I’ll let you know after the event.

    Nick James
    Participant

    That’s a really interesting report. Prentice and Alcock would be amazed at so many high quality meteoroid orbits in such a short time.

    in reply to: Something interesting by M88 #581019
    Nick James
    Participant

    I get 14.11 G tonight using a 90mm refractor from Chelmsford and the green pixels from an RGB detector. There are lots of galaxies in the field although the conditions here are very hazy.

Viewing 20 posts - 521 through 540 (of 864 total)