Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

  • Announcements

    sgl_imaging_challenge_banner_lunar.thumb.jpg.ef4882eb5fb3610f8a68e5e6913de0e3.jpg

lukebl

Advanced Members
  • Content count

    4,079
  • Joined

  • Last visited

Community Reputation

2,201 Excellent

5 Followers

About lukebl

  • Rank
    Red Dwarf
  • Birthday 25/08/59

Profile Information

  • Gender
    Male
  • Interests
    Norfolk Astronomer, bread-maker, bug and wine enthusiast. Come to Attleborough. At least it's not Watton.
  • Location
    Central Norfolk-ish somewhere, UK, 52°N 1°E ish
  1. Hope this counts as widefield. Venus/Jupiter conjunction captured at 06:40 UT on 13th November 2017, with the spire of Banham Church, Norfolk, silhouetted against the sky. About 1h 45m before closest approach. Canon 700d, Canon 75-300 zoom @ f/8 120mm, 1/2 second exposure, ISO 200. The last frame before the clouds rolled in.
  2. Chilly morning here in Banham, Norfolk. Here's a couple of images of the conjunction over 14th-Century Banham Church. Canon 700d, 0.6 sec., canon 70-300 @ f/6.3 130 mm, ISO 200
  3. Asteroid Florence I just can't get enough of these asteroids! I've got my astro mojo back after finally sorting out how to focus my Off Axis Guider, after two years with it languishing in a drawer. Perfect guiding at last! This is a capture of Asteroid Florence, currently way off the ecliptic, very near the Pole Star. Captured on 6th Nov. It passed very close to the earth in early September, and won't be that close again for 500 years. It's only about 4km across, but still relatively bright at mag 14.6. This is a total of 60 minutes of 1 minute images. No darks or flats. Each frame comprises stacks of 5 x 1 minute images. The faintest stars here are around 18th mag and the bright one is 6.8. Field of view 33 x 25 arcmin. Atik 428ex, 200mm f/5 Newtonian. Closeup
  4. Hi folks, I managed to capture these rough images of asteroid 2017VD last night, which was only discovered 3 days ago, two days after it made a close approach at a distance of 0.03 AU (3.8 million km) from Earth. When I captured these images it was moving at around 8.7" per minute and about mag. 16.8, anticipated to fade to around 21st mag by the end of the month. It's an Apollo-type asteroid with a diameter of up to 400 metres, with a very eccentric orbit that brings it within 0.1 AU from all inner planets Mercury, Venus, Earth and Mars, and within 1 AU from Jupiter. Amazing to think that it's quite big (possibly 20 times bigger than the meteorite which exploded over Chelyabinsk, of which I have a fragment), and was discovered after it had passed close by! 30 second exposures, 2x binning, Atik 428ex, 200mm f/5 Newtonian. The animation is comprised of stacks of 10 consecutive images, stacked in Astrometrica, covering a period of about 30 minutes. Stack of 25 x 30s exposures, field of view 33 x 24.8 arcmin:
  5. What's this gizmo?

    So that's what it is. It's of no use to me, so it's free to anyone who wants it. I don't even know if it works.
  6. Can anyone tell me what this is? It came with a Meade SCT I had a while back, and I've no idea what it's for.
  7. Thanks folks. The light curve was produced with Muniwin software (free) which can prepare light curves for asteroids and variable stars from a series of images.
  8. I had a great session this weekend studying my favourite celestial objects: asteroids. It was sooooo nice to get a clear night at last. Using Astrometrica, I measure the location and magnitude of selected objects and submit them to the Minor Planet Center. It seems to be an area where amateur astronomers can still make a useful contribution to the scientific community. These were all captured with an Atik 428ex cam and my 200mm f/5 Newtonian, tracked and stacked on the asteroid using Astrometrica. It really is amazing how quickly these little blighters move. I make no apologies for the rough-and-ready quality of the images. The measurements are the thing! The field of view of each image is about 29 x 22 arcmins. First up is a relative biggie, 24 Themis, discovered back in 1853. About 200km across and currently at magnitude 11.7. This is the result of 86 x 1 minute exposures: The great thing about asteroids in the main belt is that there are usually others in the same field of view, and you can make astrometric measurements of them too without having to make any more captures. Here are a some of them, also all 86 x 1 minute exposures tracked and stacked with Astrometrica. Asteroid 46965, discovered in 1998, magnitude 17.1, about 1.25 AU distant and with an orbital period of 3.79 years: Asteroid 72421, discovered in 2001, magnitude 16.8, about 0.84 AU distant and with an orbital period of 3.54 years I noticed that nearby there were two asteroids very close to each other, so I had a go at capturing them. They are 4011 Bakharev and 16852 Nuredduna. Here they are. You can see their companion nearby as a streak. These captures are the result of 100 x 2 minute exposures. Asteroid 4011 Bakharev, discovered in 1978, magnitude 16.5, about 1.14 AU distant and with an orbital period of 3.25 years. You can see Nuredduna as a streak just to its upper left: Asteroid 16852 Nuredduna, discovered in 1997, magnitude 15.4, about 0.86 AU distant and with an orbital period of 3.4 years. You can see Bakharev as a streak just to its lower right. An interesting thing I noted was that there doesn't seem to be any data on Nuredduna's rotation period, so I captured several hours' worth of images to enable me to prepare a light curve, and here it is. As you can see, there is a distinct curve, with an amplitude of about 0.4 magnitudes and minima at around 21:10 and 0:30. I assume that indicates a rotation period of around 3h 20m. FINALLY, there were several other asteroids in the field of view. here is the brightest. Asteroid 5221 Fabribudweis, discovered in 1980, magnitude 17.4, about 2.41 AU distant and with an orbital period of 5.77 years.
  9. I had a session capturing images of close-approach asteroid 3122 Florence last night, to see if I could determine any magnitude variations to show its rotation. I captured 320 30-second exposures over a period of about 3 hours, and then ran the images through Muniwin software to produce a light curve. Sure enough, my images clearly show a periodic variation of about 0.15 of a magnitude. A small range, but plenty enough for my cam to pick it up. Florence has a published rotation of 2.3 hours, which corresponds with the minima I captured at about 19:20 and 21:40. As you see, there's also a significant minimum in between the two. I guess double minima like this demonstrates significant changes in albedo or shape, although the Aricebo radar images show that it's roughly spherical. Florence is an interesting object. It's a potentially hazardous asteroid with two moons. After its close approach last month, it's now high in the northern sky in Ursa Minor at a distance of 47 million km. It's officially at mag 13.8, but my astrometric measurements make it somewhat brighter at about 13.1. Here's the light curve: And here's a quick stack of a few of the images. No darks of flats: An here's a lovely animation of the fascinating Aricebo radar images, which shows its two little moons nicely:
  10. 14 October 2017 - A daylight Moon

    Nice. So few images of this phase, compared to a waxing crescent. I guess that's because it means getting up early!
  11. So, did anyone capture the occultation? I had intended to attempt some captures to produce a light curve, but figured that my focal length wasn't sufficient to get sufficient separation between Triton and Neptune for accurate measurements. Anyway, here's a capture about 3 hours before the occultation. Neptune's in the middle, Triton is just above it, and the star UCAC4 410-143659 is just above Triton. This is a stack of just 20 x 3 second exposures, Atik 428ex, 250mm f/4.7 Newtonian. No darks or flats. I was pleased to note that the 12.7 mag star and 13.5 mag Triton were clearly visible in just 0.5 second exposures, even with a nearby full moon. The faintest stars visible in this image are about 16th mag.
  12. Ideas For Challenges

    Asteroids - appulses with DSOs or other asteroids, NEOs, Light curves, animations. I always find them fascinating, as there are countless numbers of them and they are constantly moving
  13. I love Jan/Feb/March, with the dark skies and prospect of Spring not too far away. It's the dismal grey and damp pre-Christmas Oct/Nov/Dec I can't stand. It seems to go on forever!
  14. Hi folks, This is my first attempt at measuring the light curve of an asteroid, and I'm quite pleased with the result. Thanks to Dave Smith for introducing me to Muniwin software, which was used to calculate the curves. I chose a known fast-rotating asteroid for my first attempt, 216 Kleopatra, to make it easier. It turns out that Kleopatra is very interesting. It is bone-shaped (217 × 94 × 81 km) and has two moons. Being bone-shaped, I figured that its magnitude would be pretty variable as it rotated, and I was right. It's currently easy to find in Aquila at around 11th magnitude. I took a series of 30 second exposures over period of about three hours, and then processed it with Muniwin. I haven't yet figured out how to get the actual magnitude with the software, but it does show the magnitude of the asteroid relative to a reference star. As you see, the asteroid's magnitude changed smoothly by about half a magnitude over a period of about 90 minutes. A check with Astrometrica confirmed that at 20:10 its magnitude was about 10.8, falling to 11.3 at 21:40, and rising back to 10.9 at 22:22. There's an interesting little blip at about 20:50. Perhaps an additional irregularity in its shape? Here's one of the 30-second frames
  15. Hi, Just wondered if anyone here picked up this 200mm SCT Celestron at today's auction in Leics. I thought it looked like it might have a bit of a dent (partially hidden by the lens hood!), but thought it might be worth a punt at £90 max. It eventually went for £150. Might be OK. Who knows?
×