Grant Privett

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  • in reply to: USB 2 SX camera on USB 3 port? #583079
    Grant Privett
    Participant

    How long is the USB cable?

    in reply to: USB 2 SX camera on USB 3 port? #583054
    Grant Privett
    Participant

    One question: is your camera a USB camera or a serial camera with a USB adaptor? Cannot vouch for those.

    I’ve used: Lodestar, Superstar, Ultrastar, SX H18 and Trius 694s on a USB3 under W7 and W10. No issues. 

    However, if there is a problem, then if your laptop takes Expresscards, you could perhaps install an old USB2 card. 

    in reply to: Couple of Questions about HOPS Software #583026
    Grant Privett
    Participant

    I discovered the Python Wikipedia entry this week. Highly entertaining reading. About the only thing it doesn’t do, apparently, is turn water into wine – well, thats what the zealots appear to think it seems. 

    in reply to: C/2020 F3 (NEOWISE) #582959
    Grant Privett
    Participant

    Could you tell me what sort of circular polariser it was please? Am sort of surprised it was so successful against the linear signal from the comet.

    Is it one that normally fits on a DSLR camera lens?

    in reply to: C/2020 F3 (NEOWISE) #582930
    Grant Privett
    Participant

    Really nice to see this.

    The comet is approx 30 degrees from the sun, so the background should display Rayleigh scattering induced polarisation of a few percent. From memory, the orientation in the first image looks roughly right given the suns position pretty much below the north horizon. The comet should have its own dust response – as the Zodiacal light does – and certainly appears to here. I’m a bit perplexed by the orientation of the background polarisation in the second image though. Was the amplitude the same?

    Your amplitude measure, was that a Stokes parameter or the degree of total linear polarisation or similar?

    I imagine perfect alignment of the 4 polariser images is essential to the values measured when the target has fast changes in brightness. I have always had greatest problems getting good results in parts of the image with steep gradients – subpixel registration is important (I found to my cost).

    I assume you only used linear polarisers.

    in reply to: New Starlight Xpress spectrometer #582923
    Grant Privett
    Participant

    Thanks for the clarification(s) on why you seemed to object to the device. Nice to understand the rationale. I must admit I rather liked the idea of using the PHD slit option. Seemed quite sneaky but can see why a mirror system might work better.

    As you say, it ideally needs someone impartial trying both and seeing what works best in practice.

    in reply to: New Starlight Xpress spectrometer #582914
    Grant Privett
    Participant

    I wondered if any internal reflections made it visible. But and x/y cordinate should be enough really.

    in reply to: New Starlight Xpress spectrometer #582911
    Grant Privett
    Participant

    If the Lodestar x2 is being used for guiding, would it be possible to display that guiding frame in semi real time? Would really need to ask Terry or Michael I imagine.

    Would make sense – the Lodestar x2 isnt a bad imager (SX7 without the cooling). But would you see where the slit was?

    in reply to: New Starlight Xpress spectrometer #582909
    Grant Privett
    Participant

    My take on it was that its self contained and very suitable for those lucky well heeled souls who have scopes at remote dark locations and so want the whole lot easily controllable and adjustable via a GUI. Similarly for university observatories to train up the students.

    Thinking about it, there must be a market out there at some of the ITelescope type sites for a few of these. Look how long we had to wait for a spectrum of the new nova in Reticulum.

    I too would be curious to see how it performed, preferably via a review done by someone not too bought-in to existing technology/manufacturers. People do tend to become tribal and sometimes don’t want to hear that something else is good in case it reflects poorly on their own purchase choices. I imagine we can all think of instances…

    in reply to: New Starlight Xpress spectrometer #582905
    Grant Privett
    Participant

    Morning,

    I’m not really understanding what you don’t like about the new system. Concave grating corrected for astigmatism, on board ref, onboard flat and onboard focusing/guiding. I don’t do spectra, but that would certainly seem to tick some boxes.

    Yep, I am ignorant, but I’m not seeing a lot to dislike beyond the price – but then again I struggle to understand why so many salivate over high end 4″ refractors when the same money would buy a 14″ Newt.

    I don’t imagine the BAA will be subsidising purchase of these like they did for the Shelyak systems a year or two back.

    What am I missing? 🙂

    in reply to: New Starlight Xpress spectrometer #582901
    Grant Privett
    Participant

    Thanks for the headsup. Am watching it now.

    Blue CCDs. Excellent. I can have a camera that matches my eyes! I don’t care what colour it is as long as it still does the business but some people like their kit to be pretty. At least its not red.

    in reply to: C/2020 F3 (NEOWISE) #582884
    Grant Privett
    Participant

    For me the comet is still naked eye and about 5-6 degrees long. It was a bit hazy last night so tougher to see by direct vision but still there: https://britastro.org/node/23435

    No obvious sign of banding in the dust tail but when using Live View the coma was clearly green.

    Its been a real treat to have some tolerable weather and a comet with two bright tails.

    We should start to see some images from Aus in about 10 days time… Hope its stays bright for them.

    in reply to: C/2020 F3 (NEOWISE) #582853
    Grant Privett
    Participant

    Is it just me or is the blue ion tail becoming more prominent, or is it merely that the comet is higher in  the sky now?

    Attached is a stack from the night of 17/8th July. When the comet spent an hour just above a line of clouds on the northern horizon.

    in reply to: Braided structure in F3 NEOWISE dust tail #582823
    Grant Privett
    Participant

    They want fame, notoriety and followers – that way lies a big ego boost and advertising revenue. You see quite a few, er, augmented, pictures these days. Some more subtle than this.

    I’m only surprised its not the Zetans coming in off the shoulder of Orion at last. 🙂

    in reply to: C/2020 F3 (NEOWISE) #582746
    Grant Privett
    Participant

    Morning of the 6th there were tiny gaps in the cloud and drizzle. 

    Morning of the 7th a bank of cloud from N-NW with tiny gaps, but huge clear bits overhead. Stood and hoped for an hour but didnt see it with binoculars nor on the SLR.  🙂

    Perhaps tomorrow.

    Despite that, the stillness of the predawn was wonderful.

    EDIT: Eventually saw it evening of 10th. Worth the wait. Alas I fell asleep in a chair waiting for it to clear some trees for the 2am observation.

    in reply to: Signal to Noise Ratio (SNR) estimates #582671
    Grant Privett
    Participant

    AstroArt7 does too – but obviously you would need a paid upgrade. Though AA7 is impressive and, most importantly, has a nice scripting language which is useful.

    in reply to: A ring around a red star #582669
    Grant Privett
    Participant

    I have a Baader Oxygen filter which seemed to leak. I gave up using it because of it.

    There may have been a faulty batch at some point.

    in reply to: Photometric filters #582611
    Grant Privett
    Participant

    This evening the Farpoint site was still showing them as available – though not always in stock.

    in reply to: Crew Dragon launch #582502
    Grant Privett
    Participant

    As far as I understand it, about 10 mins after launch the second stage separates from the dragon capsule. Presumably, it then lags behind steadily as drag and the capsule thrusters start to do their thing. So, by the time they pass over us it would be quite a big separation. Anyone any ideas how big?

    I’m wondering what lens to use to get both. As I’m only using a tripod, I’m assuming something like a 85-135mm with a short exposure and high ISO to avoid tralling. 

    This is going to be fun. 🙂

    PS I believe that on this variant of the system the solar panels are actually fix mounted on the vehicle and do not deploy.

    in reply to: Crew Dragon Visibility from UK #582500
    Grant Privett
    Participant

    That looks like a rather nice way to spend some time this evening.

    Now we just need good weather here and at Canaveral. 🙂

Viewing 20 posts - 241 through 260 (of 470 total)