lukebl

My wretched iPad just updated itself to iPadOS 14.6, and now says 'SkySafari Pro Needs to be updated. The developer of this app needs to update it to work with this version of iOS'. Has anyone else had this problem, and can I re-install an earlier iOS? How dare Apple do this to my most expensive app and leave me in the lurch! 🤬🤬🤬

That looks identical to the one I had in the 1970s. That was all we could afford, but it got me an O-Level in astronomy! Very fond memories. (I a got Grade A, by the way!)

The view of mid-eclipse from Banham, Norfolk. The clouds add a sense of drama, I think.

Some quick captures of the full supermoon rising over my local church in Banham, Norfolk, last night. Canon 700d, Canon 75-300mm zoom @ 300mm, cropped.

No I didn't take any bias frames. They've never seemed to make any difference before, but perhaps I'll give it a go.

As I've mentioned on another thread, I'm struggling a bit with my Atik383L+ which is a bit of a disappointment after my old 428ex and even my vintage SVHF-H9. Can anyone exlpain what these black lines are on this stacked image? This is about 50 frames with darks and flats stacked in DeepSkyStacker. I can't see anything untoward on any of the individual flats, darks or lights.

Thanks! I’ve long realised that I’m not capable of showpiece images, so I concentrate more on nerdy stuff that I find interesting!

Had a very interesting session doing some photometry on asteroids last night. You can usually observe their rotation by a dip in the magnitude over a period of time. The more irregular ones show the greatest fluctuation. I noticed that asteroid 1727 Mette is well-placed in Serpens and has a fast rotation of about 3 hours, and I managed to capture 5 hours-worth of images. It's just a small object about 5-8 km in diameter and is a Mars-crosser asteroid, orbiting every 2.52 years. Here is a light curve I prepared using data from the photometry program Muniwin. It's derived from 100 x 3 minute exposures, binned 2x captured with an Atik383L+, Omegon RC cam. Once Muniwin had processed the data it came up with this strikingly obvious rotation curve, with its magnitude ranging by about 0.35 magnitudes over a period of 3 hours, matching the official rotational data with a peak at around 23:37 and another at 2:32. As usual with asteroid magnitude curves, there are two peaks and troughs per rotation. There are a few binary asteroids, like Antiope, which behave like eclipsing binaries when lined up correctly, so I hope to capture that some time. Here's a capture of the whole field, with the position of Mette at 22:24 and 2:57 highlighted. Based on two 5 x 3 minute exposures. The brightest star here is magnitude 7.8 and the field of view is 38.5 x 29 arc minutes. And here's an animation of 9 clipped frames over the session, 15 minutes apart

Thanks for all the reassurance, folks. However, I think I'll always regret selling the 428ex. I'll have to sort out my dithering. People tell me I'm very good at dithering!

I recently acquired a used mono Atik 383L+ to replace my Atik 428ex, as it seems to have rave reviews and I needed a bigger sensor than my 428ex. However I really miss the awesome 428ex. It was incredibly sensitive, able to pick up really faint objects with relatively short exposures, and had virtually no noise or hot/dead pixels. I didn't even need to take darks. On the other hand the 383 has thousands of hot pixels and is nowhere near as sensitive as the 428. Is it faulty? Here's a 2x binned dark frame, heavily stretched to show all the hot pixels. Is this normal? I can live with the column of hot pixels on the right, but DSS can't seem to get rid of the the blizzard of hot pixels.

I've had a go at capturing some interesting distant trans-Neptunian objects. These three are well-placed at the moment. The second two are quite easy to capture, but the first was tricky, being pretty dim (mag 19.5) and at a relatively low altitude. All positions were confirmed by Astrometrica. The field of view of the images is 38.6 x 29.1 arcmin. This is 90482 Orcus. Until this week I'd never heard of it. It's similar, but smaller than, Puto with a diameter of 910km. It occupies a similar 247 year orbit but at a different orbital inclination, and even has a similarly large moon. Apparently regarded as the 'anti-Pluto'. Discovered in 2004. Named after the Roman god Orcus, punisher of the condemned in the Roman underworld. Nice job. 17 x 5 minute exposures, binned 2x, Omegon RC8 (1624mm FL, f/8). Atik 383L+. Very tricky to make out, but distinct on the original images. I was plagued with satellite trails, which can still be seen. This is 136472 Makemake, the brightest trans-Neptunian object after Pluto with a 306 year orbit. Makemake was one of the objects whose discovery prompted the International Astronomical Union to reconsider the definition of a planet and to create the new group of dwarf planets. Effectively demoting poor Pluto, which as we all know turns out to be awesome. 12 x 2 minute exposures. Here's an animation showing its position on 5th and 10th April Finally, this is 136108 Haumea. It has a very fast rotation for a big object, about 4 hours, which is apparently why it has an ellipsoid shape. There was some controversy about its discovery in 2004. After the discovery was announced by an observatory in Hawaii, a Spanish team claimed that they discovered it first. It turned out that the Spanish team used early leaked data and found it on some earlier images. I think there's some bitterness there! Both Haumea and Makemake are near Arcturus right now. Here's an animation showing its position on 5th and 10th April

I’m afraid that you won’t be able to see them. Their surface magnitude (as opposed to their total magnitude) is so low (barely brighter, possibly even lower, than the daytime sky magnitude) that you won’t see them. I’ve viewed them both before sunset, but opposite the sun and with a darkening sky, and even then they were so faint and diffuse you could barely see them. I’ve seen Sirius in broad daylight, but that’s an intense point source. Now, with them being close to the sun in a bright sky you don’t stand much of a chance. However, feel free to prove me wrong!

Here's a couple of animations of passes of the International Space Station over my garden, on the 22nd and 23rd March. I captured it by hand-tracking the scope using the viewfinder whist simultaneously clicking the shutter. At least with the size of the sensor on the DSLR, there's a fair chance that the target hits the sensor somewhere These are comprised of around 56 frames over a period of about 2 minutes. Omegon RC8 (fl 1624mm), Canon 700d, 1/1000 sec exposures @ ISO 800. Gif manually stacked and created in Photoshop (very time-consuming). At closest approach, the ISS was 467km distant on the 22nd, and 522km on the 23rd. 22nd March 2021: 23rd March 2021: Well, that's that last bit of astronomy (or gardening, or driving) for a few weeks for me, as I had surgery on my hand yesterday to treat Dupuytren's contracture, and won't be able to properly use my left hand for a few weeks. I was meant to go in last year to have it done, but it was postponed due to Covid, but they suddenly found an immediate vacancy. I naïvely thought it would be a quick half-hour procedure. However, it was 2 hours with painful tubes in my arteries to paralyse my arm, then 2 more hours fully conscious in the operating theatre whilst they cut open and then sewed up my hand. All just to straighten a couple of wonky fingers! Currently intensely painful even with strong opiates and a dead arm. Ah well, all praise to our awesome NHS!

Here's a fun animation of tonight's pass of the International Space Station over my garden. I captured it by hand-tracking the scope using the viewfinder (no mean feat, particularly when near the zenith) whist simultaneously clicking the shutter. It's a bit blurry and grainy, but it's quite small, the seeing was bad and my hand's not very steady! This is comprised of 56 frames over a period of about 2 minutes. Omegon RC8 (fl 1624mm), Canon 700d, 1/1000 sec exposures @ ISO 800. Gif created in Photoshop At the end of the clip the ISS passes fairly rapidly into the earth's shadow.

I was going to suggest Uranus too, but then I thought that twice during its 84 year orbit, the planet would be ‘side-on’ (can’t remember the terminology) to the sun and its moons could potentially cast a shadow.

I bought mine a couple of years ago, in anticipation of prices going through the roof post-Brexit. I think I'll be proved correct. I'd better shut up now before I stray into dangerous territory!

I started that thread about my struggles with Ritchey Cretien collimation, which vlaiv referred to earlier. I would point out that one significant positive thing about them is that they hold their collimation extremely well, so I’m not sure where you got the idea that they need constant collimation. Despite my trials and tribulations, I have now mastered RC collimation, which is easy once you get the hang of it! I take it on and off the mount frequently when swapping with other scopes, and it never needs re-collimation.

That's interesting. I didn't think anything could deal with LEDs, as they emit light across the spectrum. I thought that any filter which cut out LED light would also cut out starlight.

You are correct. Regrettably, LP filters don't work with LED lights.

I think you can forget about viewing this from northern latitudes. According to the JPL Horizons website, which calculates ephemerides for all solar system objects, on the 21st it’ll be around magnitude 12, but at a declination of 40 deg S, so not visible from Northern Europe. It then rapidly swings north at closest approach, but plummets to around magnitude 20 by the following night.

Great capture. And thank you so much for not putting a music soundtrack on it, as seems to be the trend!

Hi folks. Here's a capture from last night of this earth-crossing asteroid, scheduled to have a very close pass again in 2029. Firstly, apologies for the horrendous gradient on the images. There was some stray light coming from somewhere, and I was sumultaneously enjoying a party via Zoom, and the jovial ambience and wine meant I didn't take it seriously enough! Anyway, as you may know, Apophis was discovered in 2004 and it was briefly thought that it might collide with earth in 2029. It's 370 metres across, so would do a fair bit of damage, but latest calculations show that it'll miss by a few thousand kilometres. Close enough to get to magnitude 3 though, and maybe knock out a few satellites. Last night it was at its closest on the current approach, at around 44 times the distance to the moon, and around mag 15.5 200mm f/5 Newtonian, Atik 383L+ cam, binned 2x, 15 second exposures. No darks or flats. This is 50 x 15 second exposures, stacked on the asteroid using Astrometrica. Heres an animation, made from 10 x 15 second stacked frames, with intervals of 6 minutes between images. Note the visitation by some of Musk's Starlinks on the left-hand side. And here's another animation centred on the asteroid (the asteroid's the stationary dot in the centre).

Hi. It’s definitely a geostationary satellite. True, they are stationary relative to the observer, but moving relative to the stars and a guided mount and camera. There are thousands of them, a few degrees south of the celestial equator when seen from the northern hemisphere. Bit of a pest when imaging, say, the Orion or Horsehead Nebulae.

Well, whatever to do, I'd like to book my place with you! I was lucky enough to be able to travel to Casper, Wyoming, for the 2017 eclipse. The weather was perfect, and I can't wait to see another one. Hopefully the covid crisis will be over, and I'm still alive!

What with the latest successful landing on Mars, I was thinking about the excitement about the discovery of Methane in the Martian atmosphere and it being a possible indicator of organic life. Could someone explain why that’s so exciting when the outer planets are full of the stuff and no-one’s suggesting that, say, Neptune’s methane is a sign of life. And even on earth, methane can apparently be created by chemical or geological processes. What makes Mars’s methane so special? I was probably asleep during that particular lecture....