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lukebl

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Posts posted by lukebl

  1. Here's my entry. Full Moon rising over Thessaloniki on 13th July this week.

    Had a short break to this lovely city (well worth a visit) to celebrate my son's completion of his A-Levels. Viewing from our apartment balcony, I'd noticed on previous nights that the full moon was likely to rise behind the distant hill (Λάναρης λόφος, which Google tells me translates to Lanari Hill), and so it did.

    Canon 700d, Canon 70-300mm zoom @ 300mm

    52217969016_a9ee2c61cc_k.jpg

    A late flight last night meant that we didn't arrive home till 4.30 this morning, but during the flight and on the drive home were treated to the most magnificent display of Noctilicent Clouds I've ever seen. If my companions weren't so tired and grumpy, I'd have stopped to try and capture them!

    • Like 9
  2. It bothers me that the diffraction patterns from JWST images form a rather flattened six-pointed star, rather than a neat symmetrical hexagon, if you get my drift.

    …but I guess that’s a me problem, as my son constantly tells me.

    • Like 1
  3. Here's a slightly better ISS solar transit than the one I posted a couple of days ago. They are usually bang on time, but this one was about 7 seconds late. I guess it must be something to do with orbital corrections. ISS angular size: 50.03″; distance: 552.29 km. Transit duration: 0.76 s

    As you can see, seeing was very wobbly in the heat and it was a bit breezy, with the result that the image is boiling somewhat and the ISS path appears to have a bit of a curve.

    Coronado PST, TAL 2x barlow, ZWO ASI290MM cam. c0.65ms exposure, c 35fps. Captured with Fircapture.

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    • Like 19
  4. I set out today to capture a solar transit of the International Space Station with my Coronado PST. It was a close pass, with the station only 485km distant and with an angular size of 57".

    I thought I'd aimed it correctly, but clearly not. The ISS just appeared in two frames, clipping the bottom left-hand corner. Better luck next time. I find it really difficult to orientate yourself with the sun and predict where the ISS will go, even with the information on transit-finder.

    Coronado PST, TAL 2x barlow, ZWO ASI290MM cam. c0.6ms exposure, c 50fps.

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    • Like 7
  5. Here's a capture of the Kuiper belt object Makemake as it passed by the nice little 12th Magnitude spiral galaxy NGC 5012 in Coma Berenices. Captured on Friday evening (27/28th May 2022). Makemake is the second furthest dwarf planet from the Sun and, so far, is the third largest dwarf planet in the solar system, discovered on March 31st 2005.

    Despite relatively bright twilight and the lack of astronomical darkness, 17th magnitude Makemake was distinct even with short exposures. I tried to capture it again last night to show its movement over two days, but an as-yet unresolved failure in guiding meant I didn't have any useful exposures. However, you can clearly see its movement in the first and last captures from Friday night, about 3 hours apart. Amazing that something so far away can show such discernible movement in such a short time.

    250mm f/4.8 Newtonian, Atik383L+ cam, binned 2x, 45 x 180 second exposures. Stacked in Astap, Processed in Photoshop.

    Field of view 51.7 x 39 arcmin.

    52109584294_5811f75e46_h.jpg

    Here's the animation:

    52109345488_f1783204a7_o.gif

    Here it is with the galaxies labelled in Astap.

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    • Like 16
  6. This is a magnificent sweep of galaxies in Boötes. Zoom in and you'll see literally hundreds of galaxies here of all types. In the centre is the face-on spiral NGC5435 with its companion edge-on spiral NGC5434B or UGC08967. The brighter members of this group are apparently 250 million light years distant. There are some quasars here over 11 mly distant. The bright star at the bottom is 6th magnitude HD122563, 773 light years distant.

    I captured the luminance on 26th April, and was despairing of getting any colour due to moon,  clouds and the oncoming permanent twilight, but managed to capture enough R & B last night to give it a flush of colour.

    Captured using an Atik 383L+, 250mm f/4.8 Newt. 45 x 300s exposures luminance, 15 x 180s R & B binned 2x, synthetic green channel. Stacked in ASTAP, processed in Photoshop. Field of view 51.6 x 38.9 arcmins. 0.924 arcsec/pixel. According to ASTAP, I've captured objects down to about mag 21 here.

    52061422285_b8cacf9b04_k.jpg

    Labelled:

    52060934356_e17c4c76de_k.jpg

    • Like 6
  7. On 01/05/2022 at 16:22, Grant93 said:

    Had to choose a target which also didnt reach meridian during the night, so I wouldn't have to wake up to do any flips

    It’s worth noting that you can go well beyond the meridian without needing a flip. In fact, I have never bothered with the hassle of doing a flip. I often image a subject until it’s, say, 2 or even 3 hours beyond the meridian and it’s usually fine.

    Recently I’ve been choosing objects which transit at about midnight UT, and stop imaging (automatically, as I’m not naturally a night owl!) at around 3. This’ll give me potentially 4-5 hours of capturing time at this time of year.

  8. 9 hours ago, JOC said:

    That's lovely.  You've got the focus spot on too - I've taken some shots of stars with my camera and know how difficult it can be to get the stars as sharp as that.  The foreground trees and slight pinkness in the sky all make it quite atmospheric.

    Many thanks! There was some inevitable star trailing with 4 sec exposure on a fixed tripod, but I think it worked out quite well. I thought that the Pleiades would be lost in the horizon haze and high cloud, so was pleased that they were bright and clearly visible.

  9. Here's an interesting little string of galaxies in Virgo, viewed from a different perspective.

    Sometimes the reverse image can appear to show better detail. To my eyes, the lovely barred spiral NGC 5850 (c. 130 Mly distant) at the top looks more pleasing in reverse (it looks like the eye of a frog to me!). The others here are the elliptical galaxy NGC 5846 and 5846A below it, NGC5845 below them and 5839 at the bottom. Near the right edge is the spiral galaxy NGC5848, with many fainter distant galaxies around.

    60 x 300s exposures, ATIL 383L+, 250PDS Newtonian. Stacked in ASTAP. Field of view 51.5 x 38.7 arcmin. 0.924 arcsec/pixel.

    52023940751_509fe48e1b_k.jpg

    Labelled:

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    • Like 2
  10. Here is a lovely group of galaxies in Virgo, the jewel being the lovely spiral NGC5364 at upper left, discovered by William Herschel on February 2 1786. To its lower right is NGC5363, a lenticular galaxy, c 60 million light-years distant. Near the bottom is the spiral galaxy NGC5356. The bright star to the right of NGC5363 is 8th magnitude HD121605.

    Captured using an Atik 383L+, 250mm f/4.8 Newt. 67 x 300s exposures luminance, 20 x 120s R & B binned 2x, synthetic green channel. Stacked in ASTAP, processed in Photoshop. Field of view 50.6 x 37.7 arcmins. 0.922 arcsec/pixel

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    51979430925_1cdc80fbc4_k.jpg

    • Like 12
  11. Herewith my offering of Messier 100 (NGC4321) and friends, a 'grand design' intermediate spiral galaxy Coma Berenices, one of the brightest and largest galaxies in the Virgo Cluster and is approximately 55 million light-years distant.

    Atik 383L+, 250mm f/4.8 Newt. 58 x 300s exposures luminance, 20 x 120s R & B binned 2x, synthetic green channel. Captured over the nights of 24/25, 27/28 March and 1/2 April 2022.

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    • Like 7
  12. On 25/03/2022 at 19:25, StuartT said:

    Let me give you a tip - Astro Flats Pro. It's a truly amazing Photoshop plugin. I always use it as my final step https://www.prodigitalsoftware.com/AstroFlatPro1_News.html 

    WAY better than Gradient Exterminator

    Thanks for that tip. Never heard of that Plugin before. I've just given it a try and it's a complete game-changer!

    As you say, WAAAAY better than GradientXterminator. It's particularly good at uneven and blotchy gradients, which GradientXterminator can't deal with.

    • Thanks 1
  13. I’ll probably wind everyone up with this question, but it is a genuine puzzle to me. 

    Why is it that when folk buy an 8 or 10” SCT, with a focal ratio of say f/8 or f/10, they immediately slap on a focal reducer to bring down the focal ratio and focal length for imaging? I know that it’s partly to reduce aberrations when imaging, but if the focal length is too much, why not just get something with a native lower focal ratio and length in the first place, like a Newtonian? Cheaper, too. I’ve owned SCTs myself, mainly to capture smaller DSOs and planetary detail so I’m not anti-SCT, but it always struck me that adding a focal reducer defeats the whole advantage of havIng the longer FL. Which is why I went back to Newtonians. Much simpler and more logical.

    Now strike me down…
     

    • Like 1
  14. The Twin Quasar Q0957+651 is an amazing object in Ursa Major, and surprisingly easy to capture. The first discovered example of gravitational lensing as theorised by Einstein.

    It's apparently 8.7 Billion Light Years away (174 times more distant than the galaxy NGC3079 in this pic), and the gravitational lensing effect caused by an intervening (unseen) galaxy results in the light taking two paths either side. The single quasar thus appears as two separate points of light, separated by 6 arcseconds. The A component has a magnitude of 16.7 and the B component 16.5. There is a 417 time lag between the two images as one of them has a longer light path!

    Captured over three nights with an Atik 383L+, 250mm f/4.8 Newt. 52 x 300s exposures luminance, 18 x 300s R & B binned 2x, synthetic green channel, 12 x 600s HA binned 2x

    51959718461_77223343c5_k.jpg

    • Like 14
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