Graeme Coates

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  • in reply to: Accommodation at dark sky locations for astronomy(?) #620004
    Graeme Coates
    Participant

    There is accommodation at E-EYE in Spain. It’s not too bad a drive from Seville.

    (Disclaimer: I have a jointly run rig hosted by them – but, as a customer, I have stayed there when setting up and found it very comfortable).

    in reply to: Bias Frames for CMOS #619891
    Graeme Coates
    Participant

    As Ian says above, taking matching darks, flats and matching flat darks with the same temp, gain and offset is all that’s required (in my experience, taking and trying to apply bias frames makes everything *much* worse – I fell into this trap when first starting with a CMOS camera…).

    On a practical point of view, it’s useful to pick two gain/offset combinations – one for broadband imaging with low gain, and one for narrowband with high gain (you need a bit of work to determine offset to ensure you don’t clip the pixel values at the lower end through insufficient offset) – then stick with them, and a few exposure times – these again should be determined to ensure the sky background noise swamps read noise. This makes taking calibration frames much less onerous, and with set point cooling, (the darks at least) can be reused for some time if you have set point cooling.

    in reply to: 2023 Quadrantids #614976
    Graeme Coates
    Participant

    The item about the Quadrantrids on the 10pm BBC News with Reeta Chakrabarti was illustrated with three polar region images “from Northern China last year”. Two of these, including the one she held her hand up to to demonstrate the meteors, had (despite some nice star trails) not a single meteor captured…

    At least they tried I suppose…

    in reply to: Help in identifying galaxy in image #614612
    Graeme Coates
    Participant

    The galaxy is present on DSS2 and PanStarrs plates (see Aladin screenshot) – I don’t think it is IFN – it’s a UV source, which seems unlikely for cold dust/gas.

    There’s quite a lot of galaxies that don’t appear in “standard” catalogues (and you do sometimes wonder how it was missed when others weren’t) – I think the GALEXASC reference is as good as you’re going to get here. It does look like a small, but interesting galaxy – possibly irregular or interacting? – the PanStarrs data (attached) is maybe clearest, but even then, it’s not enough to get a clear view as it were.

    in reply to: Spiders #613212
    Graeme Coates
    Participant

    Already have a large cover on it when not in use, in addition to Scopeshroud covers round the truss portions, but this doesn’t seem to deter them…

    The cover may well encourage the spiders to take up residence I guess, but it’s the lesser of two evils perhaps versus protection against snail poo and any potential water ingress. I’ve used a truss newt before with a tarp over the top when not in use and don’t recall such an issue.

    No geckos to deal with in Oxfordshire however!

    in reply to: Spiders #613210
    Graeme Coates
    Participant

    That’s a good idea, thanks – I fully expect that the snails enter through the gap between dome and base looking for a cool place to hide with plenty of condensation on the inside, so potentially (after a good eviction session…) that may prevent re-entry… Certainly beats having to waste beer on a trap in the dome!

    in reply to: U Sco possible eruption #610939
    Graeme Coates
    Participant

    Here’s a single 60s exposure with Green filter – U Sco is marked centre of frame. North is left.

    Star A is HD 147473 (Mag 6.87V)
    Star B is HD 146592 (Mag 7.06V)

    in reply to: U Sco possible eruption #610926
    Graeme Coates
    Participant

    Managed to capture from Spain (EEYE) this evening (80mm f5, STF8300M):

    07/06/2022 22:14:12UT TG 9.126 (0.024)
    07/06/2022 22:14:59UT TG 9.158 (0.015)
    07/06/2022 22:15:30UT TG 9.129 (0.016)

    • This reply was modified 1 year, 10 months ago by Graeme Coates.
    in reply to: ER Uma and RZ Lmi: Observations requested. #584387
    Graeme Coates
    Participant

    ER UMa appears in outburst this evening:

    Jun 23.907UT – 12.83CV

    in reply to: CG Dra: a VSS campaign #584385
    Graeme Coates
    Participant

    Looks like this is a “long” type outburst – appeared to be still brighter than mag 16 this morning from Spain:

    Jun 23.131UT  15.84CV (+/-0.04)

    in reply to: CG Dra: a VSS campaign #584228
    Graeme Coates
    Participant

    Looks like it’s on the fade after the peak on the 13th/14th – back at about 16.7CV early this morning (17-May-21 03:18-03:56UT).

    in reply to: ER Uma and RZ Lmi: Observations requested. #584183
    Graeme Coates
    Participant

    Appears to show superhumps with period similar to the published 91.67min (going from the minima). Data in BAA VSS database for analysis. Got hindered by next door’s greengage tree, and software hang at the end…

    (Clear filter with V comparison stars used. 40sec each, ST2000XM+350mm Newt @ f4.52)

    in reply to: ER Uma and RZ Lmi: Observations requested. #584182
    Graeme Coates
    Participant

    Currently 13.0-13.1CV (21:40-22:20UT on 6th May 2021). Answers on a postcard for this intruder…

    in reply to: ER Uma and RZ Lmi: Observations requested. #584179
    Graeme Coates
    Participant

    Forecast looks OK for me this evening – I’ll have a go if OK. 

    in reply to: ASASSN-21gk – spectra urgently required #584178
    Graeme Coates
    Participant

    This appears to be a strange object – at first sight of the AAVSO light curve, it almost looks like a poorly sampled eclipsing variable with a period of about a day and a bit: but it makes little sense that it has suddenly started to vary having apparently been non-variable up to this point – and with at least half a magnitude of variation as well now! Odd! 

    in reply to: Pic du Midi #583851
    Graeme Coates
    Participant

    Well, yep – touristy; if you’re not into the religious aspects, which is the main reason why so many people visit each year, there’s so many better places to go nearby.

    in reply to: Pic du Midi #583845
    Graeme Coates
    Participant

    No problem – I should have said, the TGV may also work if you don’t want the overnight. I would probably look to do Paris -> Lourdes/Tarbes direct rather than going via Toulouse – the former is about 5hr, the latter 4h something plus the 2hr back…

    Really like the Pyrenees – it’s a great part of the world – super food, mountains, cycling, walking, places to visit etc (though personally I’d get in and out of Lourdes as quickly as I could…)   

    in reply to: Pic du Midi #583843
    Graeme Coates
    Participant

    I have visited Pic du Midi, but I took the hard route and went up there by bike! (The Col du Tourmalet is a classic Tour and Vuelta climb :-).

    You’ll need to get the bus to La Mongie to visit, as this is where the cable car goes from. I think (in normal times) there is a bus from Lourdes or Tarbes to La Mongie, which may suit you as both have SNCF stations. There was talk in summer 2020 about the French Government reintroducing the Paris-Tarbes sleeper service, but this might not happen quite yet, and there is (again in normal times) still the Paris-Toulouse sleeper, and Toulouse-Tarbes/Lourdes via train is a couple of hours.

    There is also the Cité de l’Espace in Toulouse which I can recommend as well. 

    in reply to: Timings of minima of eclipsing binaries #583704
    Graeme Coates
    Participant

    On the occasion that I do some EB ToM work, I tend to submit the timing to Gerry at the AAVSO – he collates the timings and publishes them in the JAAVSO on a 6 monthly basis – it does tend to be driven by a small number of dedicated observers from the names in the articles. I’m not sure how frequently they may their way into the Krakow/Lichtenknecker DBs of course, but at least thay are in the literature…

    (I presume the BAA doesn’t publish observations of binary ToMs in this way – or at least, I’ve not seen them published in this way, hence why I go down theJAAVSO route to do it…?)

    in reply to: IX Dra: observations requested #583668
    Graeme Coates
    Participant

    I think there were some observations at 15.5 on the evening of the 4th (in the BAA dB) so probably just after peak for my one.

Viewing 20 posts - 1 through 20 (of 30 total)