wimvb

This was a first test, so default settings only. For the very first test, I used BXT on the L master only, but that didn't correct star colours and star halos. Using BXT on the RGB master as well, fixed this.

Very nice, despite the planet's appearance. I guess you could always crop the image before processing.

To isolate true Ha from broadband red, Vicent Periz recommends red continuum subtraction. If this is not used for galaxy images, the core, which consists of old red srars but no Ha clouds, will also become red. This is actually a common mistake in galaxy image processing.

And a lot cheaper. I remember an article you wrote a few years ago, where you compared results from large telescopes to those obtained with smaller refractors. Now, the difference gets blurred even more. (Pun intended)

One more comparison that got me thinking. Here's a crop of Stephan's Quintet. Quite an improvement. All the details in my BXT version are visible in the SDSS plates, so no introduction of invented details. BUT: would it even be possible for me, with a 7.5" telescope, to capture such detail, even accounting for imperfect collimation, focusing, guiding and seeing? In other words, Can we now get images that are better than the theoretical telescope specs? And if that's so, and ok, why would one even bother investing in a large CDK and putting it in Chile or New Mexico? (top is conventional processing, bottom is BXT)

The game changer isn't just in what BXT does to the main target, but just as much in what it does to the background. With ordinary deconvolution, the background is never sharpened, because the noise gets in the way. I just downloaded an evaluation copy and used it on my version of ngc 7331, where I had previously tried to enhance the ifn and satellite galaxies. This is a crop of a small background area. BXT pulls out background galaxies, that also show up, but are unidentified in Aladin (SDSS) (UG = Unidentified Galaxy) Here's the same area from Aladin

Remember that Ha filters don't discriminate between Ha and white light at the same wavelength. A broadband target such as the witch head will also emit light at Ha wavelength. What you would really need to do is broadband subtraction: Ha - k•Red, where k is a normalisation parameter.

Thanks, Alan. Much appreciated. I'm sure many don't have a catalogue number yet. In my image of And XXX, there were several that didn't. And besides, those that do, often have "2MASX" + ra and dec coordinates. In the best of circumstances, those that do will have an entry in the NASA Extragalactic Database.

Thank you. Glad you like it. I certainly hope I can show more. But that will most likely be a project for galaxy season.

Thanks, Alan. Glad you like it. I think you should definitely start collecting photons with your 190MN.

We had quite unexpectedly a few hours relatively cloud free this night and I pointed my scope at a small group of galaxies in Lynx. I found this group by accident on Aladin, where it looked like there was a bridge between two of them. 90 minutes imaging time confirmed this bridge. This image consists of 31 3 minutes exposures with an L filter in front of my ASI294MM. As usual mounted on my SW 190MN. The central pair of galaxies is UGC 3816 and MCG+10-11-033. Both are leniticular galaxies about 170 MLy distant in the constellation Lynx. Both galaxies are also smaller than the Milky Way; they each have a diameter of approximately 35 000 - 55 000 ly. To the lower left of the connected pair is UGC 3828, a barred spiral galaxy which belongs to the same group of galaxies. This galaxy is at about the same distance and about the same size as the others Below and in line with UGC 3816 / MCG+11-10-033 is the edge on galaxy MCG+11-10-036, which is about 600 - 700 MLy distant. This galaxy is also much larger than the others, approximately the same size as the Andromeda galaxy. I haven't been able to find any amateur images of this group, and only one or two images from professional telescopes. UGC 3816 was the subject of a study about globular clusters, a year ago. https://arxiv.org/pdf/2104.00672.pdf Coming galaxy season I will collect more data (including colour), and try to show the bridge better. Inverted image showing the bridge between UGC 3816 and MCG+11-10-033

Thank you for that resource, Alan. Now there's a challenge... 😁 In the mean time, I'm enjoying a very unexpected gap in the clouds towards the East. Opened the roof of my observatory a few hours ago and have pointed my scope at a very interesting galaxy pair, which I can't find much information on. Not a dwarf galaxy, though. Those will have to wait untill the weather is stable for a longer period.

Why not a tube or a sleeve that you slide over the chimney?

Thanks. The trick is to have a camera with a high dynamic range, as this will allow you to expose above the read noise floor without overexposing stars. I use my camera at 0 gain, where dynamic range is largest, and an expose time such that only the brightest stars are blown out.

To paraphrase Mick Jagger: "I see a bright tube And I want it painted black. No r'flections anymore I want them to turn black."

Cold weather with thin clouds and a full moon makes for poor dso imaging, but very nice wide field lunar imaging. I guess tomorrow Mars will be obscured by the moon. this is truly a one shot colour image. Taken with and cooked in my iPhone

Only certain versions https://research.aalto.fi/files/91023117/Hoon_Miniature_science.pdf

Would it? You’d have all the interesting photons anyway.

Btw, Alan, if you want to go for the really faint stuff, and pixel scale isn't your first concern, you could experiment with bin 2x2 at 0 gain. Full well is four times higher, while read noise is only two times higher. In this mode, you may be able to capture faint signal while keeping the stars under control. Mind you, the pixel scale will be 2.5"/pixel (now 1.25"/pixel), and the fainter stars may look a bit blocky. But the file size will only be 1/4 and downloading will be faster. Definitely something to consider if you need long integration times.

& @Paul M, Strasbourg, the Vizier catalogues. It takes a bit of detective work, and clouds help 😁

Here's your galaxy, @symmetal All stars accounted for

Unlike Cass II (And XXX), UMa I dSph consists only of individual stars, no dust or fuzzy patch. The scattered stars give it the absurdly low surface brightness of 28.8 Mag/arcsec2. Even with a RASA you will need many hours to drown the sky brightness if it is at 21.4 Mag/arcsec2. But fortunately, the stars that make up the dwarf satellite are easier to image. https://www.astrobin.com/0gvm5z/B/ My guess is that they are in your image. I'll have a look.

This turned up in my news feed https://scitechdaily.com/advanced-lab-on-a-chip-scientists-have-created-a-powerful-ultra-tiny-spectrometer/ Products will take several years to develope, but this looks like it could radically change amateur spectrometry. “If you’re into astronomy, you might be interested in measuring the spectrum of light that you collect with your telescope and having that information identify a star or planet,” he said. ("He" is professor Ethan Minot of Oregon State University)

Very nice image, despite the conditions. This target is definitely worth revisiting under more favourable conditions. Especially if you also collect Ha. Here's data from the NASA database on the small red galaxy http://ned.ipac.caltech.edu/byname?objname=LEDA+2674762&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1

Found this through FB https://www.skywatcherusa.com/products/cq350-pro-mount-head-only-with-counterweights The mount looks suspiciously identical to iOptron CEM mounts, with their compact design. On paper, it fits between the EQ6R and EQ8, but its model number is confusing, reminds me of the much smaller EQ35. As the other large SW mounts, it has a belt drive in stead of gears, so lower backlash. Anyway, this mount falls in the same price range as the "new" JTW P75 Trident mount, which has a friction drive. And which in turn looks very much like a Mesu mount, which also has friction drive. But is double the price ... These are certainly interesting times we live in, astrowise.