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You don’t need to wait for a fast moving NEO to pass by. I regularly check my timing accuracy by doing astrometry of GPS satellites as explained by Bill Gray here:
I’ve put a speeded up version of my eclipse video here:
https://www.nickdjames.com/Eclipses/20221025/eclipse_20221025_ndj.mp4
The entire eclipse in 35 seconds.
Someone on Youtube yesterday said that watching a partial eclipse was like watching paint dry. As a public service this video is short enough that it should not stress the attention span of most social media users.
Clear here at the moment and the livestream is running. Under 30 mins to go.
https://www.youtube.com/watch?v=1nUMDx8PiF4
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My livestream on Tuesday morning will be here:
The forecast for Tuesday here is light cloud all morning so it may not be a very interesting livestream! At least it is not likely to be raining…
Much better conditions tonight but the spacecraft is now around mag 19.
https://britastro.org/observations/observation.php?id=20221018_013758_7e01f580c6581403A few tiny gaps between the rain clouds in Chelmsford. The fact that it is very close to the Moon doesn’t help but it is around 16.5 at the moment on the one out-of-focus image that I’ve managed to get.
Here’s the badly out of focus image:
https://britastro.org/observations/observation.php?id=20221017_033930_ce425b3fe9fb12a2I got the spacecraft and Centaur upper stage a day after launch in 2021 October and so will certainly be having a go for this flyby. Closest Earth approach is 11:02 UTC on 2022 October 16 when it should be visible with the naked eye from Australia. Our best opportunity is the morning of October 17 when it will be in Gemini. It was mag 17 when I imaged it on the way out in 2021 and the SWRI web page below suggests it will be 12-16 the day after flyby then fading at around 2 mags/day.
https://britastro.org/observations/observation.php?id=20211017_203152_36007e488544b44e
http://lucy.swri.edu/SpotTheSpacecraft-EGA1.htmlIt is interesting that the velocity change is larger than would be expected and it appears that much of the momentum change came from ejecta rather than the spacecraft. That is something specific to rubble-pile objects I guess. A solid object would produce far less ejecta.
That was fun to watch last night and the last image few images showed a huge amount of detail on Dimorphos. It looks like quite a few people, including some using small telescopes, detected the impact flash and subsequent dust cloud. I’m quite surprised how prominent the impact was from Earth although a quick calculation shows that the spacecraft kinetic energy was around 12GJ, so approx. the equivalent of 3t of TNT.
Hi David,
I had a great view of that comet and NLC too on the night of Friday/Saturday, 2020 July 10/11. That night was one of the best observing experiences of my life. A stunning naked-eye comet and really dynamic and bright NLC.
Sadly we don’t have anything like that at the moment. The brightest comet around in the northern sky is probably C/2022 E3 (ZTF). It is around 13th mag at the moment so probably too faint for a small telescope but we hope that it will reach 6th magnitude in late January next year when it will be moving rapidly across the sky under the pole.
The best places to go to get an idea of the current state of comets in the sky is Jonathan Shanklin’s site here:
https://people.ast.cam.ac.uk/~jds/
and our Comet Section image archive here:
https://britastro.org/cometobs/
For the latest images of C/2022 E3 scroll down to near the bottom of the list and then click on the “gallery” link.
We’re always happy to receive observations of comets so please let me know how you get on.
Thanks for posting the videos. It was a great meeting, very enjoyable and well attended. My thanks to everyone involved, particularly Hazel, the Sigma crew and Lorna and Helen at UHIM.
After giving my talk on monitoring the sky with video cameras I headed north to install one of these low-cost cameras at Denis Buczynski’s observatory at Portmahomack. This has a fantastic northern horizon and the camera is intended to capture NLC and aurora. A couple of live clips from last night show a very nice, active aurora with the foreground illuminated by moonlight:
http://nickdjames.com/TarbatnessN/TarbatnessN_20220914_2153.mp4
http://nickdjames.com/TarbatnessN/TarbatnessN_20220914_2322.mp4A still made from stacking 128 video frames is attached. It shows how well these little cameras work.
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This document has some useful background information on SLS. In particular it has a timeline including the ICPS disposal burn on page 55:
https://www.nasa.gov/sites/default/files/atoms/files/sls_reference_guide_2022_print_0.pdf
Nick.
An updated ephemeris for the rescheduled Artemis launch time (window opens on Sept 3 at 18:17 UTC) is on JPL Horizons. This has much better visibility for us on the evening of the launch. The spacecraft rises around 20:00 UTC and gets above 40 deg altitude by 21:00. The upper stage separation burn is at T + 2hr 7min so may well be visible from the UK if the sky is clear.
Let’s hope that they now fully understand the LH2 bleed and the RS-25 cryogenic conditioning problems that scrubbed the last launch and that the weather cooperates on both sides of the Atlantic.
Ted Molczan has provided a table of expected magnitudes for the spacecraft (Orion) and the SLS upper stage and spacecraft adaptor (the Interim Cryogenic Propulsion Stage) on seesat:
http://satobs.org/seesat/Aug-2022/0236.html
They indicate that Orion will be 13th mag on the night of launch fading to 17th mag at lunar distances with the ICPS around 1 mag fainter.
The ICPS will be deflected from the spacecraft trajectory by a disposal burn shortly after trans-lunar injection (TLI). This will target a lunar flyby which will put the stage into a heliocentric orbit. The stage will probably do a propellant dump shortly after the disposal burn as part of its passivation procedure. Sadly we are not going to see that from here but it could be an interesting sight for people in the right place. Have a look at Chris Taylor’s description of the equivalent from the Apollo 8 S-IV-B upper stage:
https://www.hanwellobservatory.org.uk/news/apollo-8-from-the-other-side-of-the-pond
JPL Horizons has an ephemeris for Orion but not the ICPS. It is likely that an ICPS ephemeris will appear here:
https://projectpluto.com/sat_eph.htm
Good hunting. Please post any images you get on this website.
Yes, it’s going to be a challenge. The attached plots show the visibility from my observatory in Chelmsford to give some idea. These show the altitude of the Orion spacecraft, the Sun and the Moon at the date shown along the bottom. On the night of the launch Orion is around 12 deg up at nautical twilight and descending. I don’t know how bright it will be but at 20h on the day of launch it will only be 10 deg up from here and it is already 79000 km away. The ISS at this distance would be around 4th mag and Orion is a lot smaller than the ISS.
By the time the circumstances get better it is far away and close to the Moon as you can see from the second plot.
I would love to be proven wrong and would be very impressed if anyone gets this from the UK!
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It doesn’t look good for us in the UK.
Assuming that the launch goes ahead at the start of the 2 hour window (12:33 UTC on Monday Aug 29) the geometry for the UK is poor with the spacecraft below the horizon at night for the first week. It is above the horizon in a dark sky on Sept 5/6 when it is at declination -27 and due south around 2100 UTC but, by then, it will be a long way away and close to the Moon in the sky (not a surprise really) low in Sgr.
It gets to high northern declinations on the way back but by then it is heading for solar conjunction.
All in all I doubt if anyone will image it from here. A good opportunity to use a remote telescope I think.
The seeing seemed quite stable here tonight so I thought I’d have a go tonight at doing a set of very short exposures of V482 Cyg and selecting the best ones to stack. This gives very high resolution and allows a clear separation between the variable and the 15th mag star to the NW. The variable has certainly brightened relative to that star since the image I posted on Aug 13. This image is only 3 arcmin square with a pixel resolution of 0.14 arcsec. Given that I’m not on a mountain this is probably as good as I can get.
The FWHM is around 1.5 arcsec and the circles are apertures of 1.7 arcsec radius centred on the Gaia catalogue position. This is unfiltered so the variable is likely to be quite a bit brighter than V would give.
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Hi Gianni,
Here’s an example from the top of a mountain showing its shadow at sunset. This was taken from the peak of La Palma.
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PSF photometry works well in crowded fields but the separation of these stars is only 2.9 arcsec so getting good enough focus and tracking to ensure that the PSF of each object is not too blended needs a bit of work with an amateur telescope from sea level in the UK. My image was at a scale of 0.28 arcsec/pix and had a star FWHM of 2.2 arcsec so the stars are reasonably well separated but that was on a night of good seeing. CMOS cameras allow selective stacking a lot of short exposures so a strategy similar to that used by planetary imagers is probably worth trying.
I ran source extractor on this image and it showed that V482 Cyg was about 0.2 mag fainter than the companion so probably about 15.2 unfiltered at the moment. The star is likely to be very red though.
This star has now faded to around mag 15. Gary prompted me to look at my images since my magnitude estimates of this star were too bright as it faded. One of the problems with automating everything is that I don’t often look at images or the data derived from them and there is a fairly bright star only 7 arcsec to the SW which was within my photometric aperture. The AAVSO VSX does warn about this. Looking in detail at my unbinned images tonight there is also a 15th mag star only 3 arcsec to the NW of the variable and this will generate significant errors at the current level. This is not mentioned anywhere and I haven’t seen it on other images since it is normally swamped by the bright variable. It is in Gaia EDR3 (a demonstration of how good the optics in that spacecraft are). It is worth considering if you are doing photometry of this star at the moment.
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