Knight of Clear Skies

Excellent thanks, added to basket. Always good to have a recommendation rather than taking a punt.

Yes, it's not the most readable page, I think you're looking at raw photometry data and calibration parameters. There appear to be coordinates and various magnitudes (different wavelengths, but I can't see the key). Simbad might be a bit more useful to you as it has an object type designation (often with a ? next to objects when their nature isn't confirmed). I've used Simbad a bit but it's not easy to get it to do what I want (e.g. search for a type of object around a given coordinate to identify, say, satellite galaxies or quasars). If anyone knows of a guide to using it I'd be grateful. (Failing that, a do know a professional astronomer I could ask.)

Good article here about finding quasars, there are a few above mag 14 which are suitable for visual observation.

They are point sources (well, apart from a few gravitationally lensed ones) but it's really surprising how many can be captured with amateur equipment, and at what ridiculous distances. Pretty Deep Maps is a good reference for Quasar hunting, authored by forum member Martin Meredith. I did find a link to a quasar challenge page but unfortunately it seems to have gone dead. I'm pretty sure I captured a mag 18.5 quasar in the background of this image, with a DSLR and camera lens. It's 11.6 billion light years away (lookback time, so the photons have been travelling for most of the history of the universe). But it's just a faint dot, I'd never have identified it if it wasn't in existing catalogues. A good-sized telescope should be able to take a spectrum of one and measure its redshift.

Well worth posting, shows its structure very well.

Had a quick go at a colour version, was some way into the processing before I realised I wasn't using the full resolution version but never mind.

Good to hear you'll find it useful. Yes, there are times I wonder if I've nixed or manufactured data while processing out gradients or vignetting (especially when I've had problems with flats and had to stack without them). Looking on MDW there are a number of arcs in the area. My new theory: A concentrated region of molecular cloud is stretched out by tidal forces, and radiation pressure and stellar winds from a bright star 'bend' it. (The denser and more shaded area in the middle isn't moved as far). Plausible? I think so. Accurate? Goodness knows.

Here's my latest effort, NGC 1499 in Ha. The mysterious arc feature is showing at lower-right, my goal was to capture it. Field of view is 7.84 x 5.93 deg, North is to the right. I like it in this orientation as it gives it a squid-like appearance. Although it was only shot at 135mm focal length I think it's showing enough detail for the Deep Sky Imaging forum, due to the small pixels of the 1600MM cool. This is 48 minutes of data at f2, fully calibrated. My Ha filter is designed to work at f2 but I don't know how wide it is as that information isn't published. Some people have suggested it's at least 12nm. Here's a quick go at a colour version, blending the Ha into a image taken with a 200mm lens and modded 100D. Had a go at a starless version using StarNet (it's free and very easy to use, just a case of putting the image in the right folder and then dragging it onto either the mono or colour executable file). An inverted version shows a little more detail. And finally, here's an inverted version with a very heavy stretch of the background. There is a curious angled feature at lower-left (possibly two unrelated fronts or filaments). Here's the deepest image I can find of the region, from the MDW survey. I still don't know what to make of that arc but even in a very deep image it doesn't show up as a circle. One theory is that it's a foreground faint planetary nebula in front of NGC 1499, but perhaps that's not the case. Hope you like it, would welcome any feedback. I have a colour image on disc somewhere shot with a DSLR and 200mm lens so I'll have a go at blending in the Ha using Registar.

Nice catch, I've never seen that target before, but the Draco Dwarf isn't my image.

Thanks, much appreciated. I went a bit cross-eyed on this one, my processing workflow is a bit erratic and probably could use an overhaul.

Which image is that please?

It's not obvious, that's a background galaxy. The Draco Dwarf itself has the appearance of a star cluster in centre frame, it's close enough to resolve the brighter individual stars. It has a large angular size, being about Moon sized, but the total luminosity of all its stars is less than that of some of the brightest stars in the Milky Way.

You're conflating two separate things I'm afraid. For measured criticism of the state of fundamental physics I'd recommend reading Sabine Hossenfelder. She talks here about the problems in the physics community, and has some suggestions on what problems should be investigated. But Dark Matter is a very strong theory without any direct detection of particles, in much the same way the Higg's Field was before the Higg's Bosun was detected. Similarly, neutrinos were first proposed in 1930 but not detected until 1956. String theory and super-symmetry may well turn out to be follies but Dark Matter is a fully scientific theory. (It's actual nature could be quite different from the weakly-interacting particles we imagine, but its effects a large scales are well understood.) It's not mud slinging, it's a observation that MOND theories struggle to explain. Why would gravity work radically differently in a nearby dwarf galaxy compared to others?

You're looking at images from the Digitised Sky Survey (DSS) which ran between 1983 and 2006. I think that image is from the first release which was taken with photographic plates. My favoured method for browsing various sky surveys is to use World Wide Telescope. Other interesting datasets include the WISE all sky IR survey, the SFD dust map and an all-sky ha map. For example, here's Orion in Ha and WISE IR. In IR it's much clearer that the Angelfish nebula is a supernova remnant, dust has been swept into a circular feature by the explosion. Another good trick is, if you upload one of your images to http://nova.astrometry.net/upload it gives you a link to view it in WWT, if it plate solves successfully. You can then adjust the crossfade slider to see how well different features line up across wavelengths. Hope that's of some interest.

Thanks for putting together the video and some good ideas for further ones there. A word of caution here. Dark matter is is a very strong hypothesis with multiple lines of evidence pointing to its existence, such as the rotation curves of galaxies, distribution of mass in galaxy clusters and oscillations in the Cosmic Microwave Background. We also know of one barely-interacting particle, the neutrino, which can pass through a light year of lead. Competing theories, such as modified Newtonian dynamics, utterly fail to explain the motion in dark-matter dominated galaxies such as the Draco Dwarf. It's the simplest hypothesis that explains the evidence, it's certainly no folly. There is a careful balance to be struck between open-mindedness, there are unsolved problems in cosmology and we certainly don't understand the full picture, and credulousness.

It has good pedigree. After all, the Apollo lander was wrapped in bacofoil.

Interesting. A shame this doesn't seem to be available as a clip-in filter.

If someone had a cheap telescope and plenty of time they could, for example, use blue and red filters and focus them separately. (And then create a synthetic green channel if they didn't want to lose too much imaging time.)

And thus world's newest and most ineffective super-hero team was born. My super power is that I can tell when I've forgotten to boil the kettle just by the sound the water makes as it splashes in the mug.

Glad you're doing OK. 'Minor planets' is another term for small solar system bodies including asteroids. A bit archaic maybe, but the IAU still have a Minor Planets Centre which hands out the designations. I was hoping here might be something that would take and image and time, plate solve it, and tell me what's in the field of view.

Thanks for the write-up. The jet is showing nicely, don't often see it in long exposure images.

Welcome to the forum from Bodmin Moor and thanks for your contributions to the EQ3 thread.

Yes, fingers crossed, we'll just have to see.

Maybe if we all go out and shine laser pointers at them we can knock them out of orbit. (Bonus points for crashing one on Elon Musk's truck or ego.)

Looking at the timestamps that's just shy of a couple minutes? If so, much too slow for a meteor which have a minimum speed due to Earth's gravity. Best guess it's a bit of satellite or rocket debris burning up. Does anyone know if there has been a recent launch please?