wimvb

A few remarks. 1. You have odd star shapes with a pronounced halo. How do you focus the guide scope? For good guiding, you need good focus. There used to be a recommendation to slightly defocus the guide scope, but imo, in an era of cmos cameras with small pixels, this is no longer needed. Good focus gives a better signal to noise ratio. 2. Your guide graph is all over the place. It needs to be calmed down. Start by increasing the exposure to 2 - 3 seconds to reduce the effect of seeing. Next, reduce aggression to 50 %. Make sure that your guide rate in ascom and in phd is set to 0.5. A high rate and aggression will give larger guide corrections. If most of the star movement is due to seeing, you're chasing tracking errors that don't exist, and over correct them. 3. If you have a smooth running mount and good polar alignment, then theoretically, you shouldn't need to guide in DEC. So, DEC tracking deviations can be a good indicator of seeing. On nights with poor seeing, you'd increase MinMo, which is the minimum a star needs to move before a correction is sent to the mount. On nights with good seeing, you can decrease MinMo, to benefit from the sky conditions. 4. Finally, while it is possible to reuse guide calibrations, I wouldn't do that while dialing in the best settings. It's better to calibrate too often than not often enough.

Quite a good read. So is "making every photon count", which has better quality images.

Do you use flats? If not, you really should start using them. The background pattern is ordinary vignetting. The circular dark area is the shadow of a speck of dust on probably a filter. Both are taken care of by flat calibration. The vignetting is best corrected in PI by using division as the correction method. But since gradients are a combined effect of vignetting (multiplicative) and sky glow (additive), removing them with DBE is less likely to succeed than using flats for vignetting and DBE for sky glow.

The real blast would of course be if they manage to nudge an asteroid out of its orbit, just fo find out that it will smash into earth next time around. Oops.

Looks good in ascom. But as I wrote before, if you increase alt a little, you’ll have less disturbance from the atmosphere, and neighbours’ houses.

If you point the scope south, the counterweight bar on an eq mount will point due east or west. 0 dec means that you are looking at the celestial equator (which is earth’s equator extended). From the horizon, look as many degrees up as 90 - your observing’s location latitude. For me at 60 deg latitude that would be 90-60=30 deg up. When you do the calibration, you shouldn’t point lower than 40 degrees though, so you avoid atmospheric disturbances.

Nice! I like the details you've captured. I think though that the right hand side is a bit blue. If you decrease the blue in this image, the red clouds will benefit and become more saturated. Thanks for sharing.

That's a very nice set of images. The newest generations of cmos camera are a game changer, aren't they? Enjoy yours.

What gear did you use besides a canon camera? The dust mote seems small, so should be close to the sensor. While Raw Therapee is a very handy tool for editing single images, I wouldn't use it to process stacked images. Use DSS and The GIMP instead, or invest in a dedicated astro image processing application.

I know more about physics than dinosaur anatomy. And to get this thread back on track, I know that gravity is pulling those dark clouds in my image together, and will eventually give rise to new stars and new planets. Planets that, in time, may harbour their own dinosaurs.

What workflow do you use? For me the following works. Preprocessing of L, R, G, B to create 4 masters. I use one and the same sub during image registration of all subs. This means that the 4 master images are aligned identically. Dynamic crop of 4 masters RGB channel combination DBE on the RGB image Background neutralization Photometric Colour Calibration Chroma noise reduction Arcsinh stretch of the RGB image. (This is the best colour preserving stretch method by far. Usually SCNR Green is needed to suppress a green cast.) Then I process the L master and combine it with LRGB combination. There's really no need to do DBE before channel combination unless you have complicated and persistent gradients.

Each pixel contains 16 bit data = 2 byte 2 x 11.7 = 23.4 MegaByte The bad pixel map is only 1 byte per pixel, because it only needs to be 0 or 1, and the smallest datanumber is 1 byte (not 1 bit) in size.

Ankylosaurus probably?

If you have a few million to spare. Quantum dots like these are hard to make. You need a state of the art semiconductor fabrication facility to make them on a large scale on a flat surface. The curved surface of a lense makes it even harder. The article talks about laser light which is very narrow band, similar to a narrow Ha filter. So how will it work with white light? (I haven't read the original article yet. Maybe some of these questions are answered there.)

Thanks for the link, it is an interesting article. But I won't change the title of my post for it. 😉

Jurassic park was hardly a documentary. Pretty impressive CG effects though, at the time. So this diving Bronto would be more accurate? Or didn't they swim at all? At least the image has correct orientation.

This dark cloud in the sky reminds me of the brontosaurus scene in Jurassic Park, where one of the big dinosaurs stands on its hind legs to reach for leaves in the high canopy of a tree. The image shows part of Lynds' bright nebula complex LBN 603; LDN 1295, LDN1296 and Tokyo Gakugei University catalogue index H809. Data for this image was collected during three unexpectedly clear nights in early November, and consists of 15 hours of RGB data. Clear nights in this case meant that there were high clouds and on one occasion ground fog. Fortunately my observatory is on a slope above the local fields. But the moisture resulted in soft halos around the brightest stars. As usual, captured with my 190MN on an AZ-EQ6 mount and a ZWO ASI294MM camera with Optolong RGB filters. On average 5 hours per channel. Processed in PixInsight.

Very nice, Rodd. What gain do you use? 60 s with a C11 seems very short. I use 120 s with an f/5.3 scope at 0 gain.

I've seen that too. In Sweden, where roundabouts/traffic circles are all too common.

This depends very much on your scope’s f-number and focuser. For my f/5.3 scope with Pegasus Astro focus cube, I use a step size of 50. If you use a reflector, the auto focus routine will have difficulties handling donut shaped stars, so keep the maximum travel in the region where this shape isn’t pronounced. Do a coarse focusing with a B-mask or by ”guesstimation”

Not even the short end?

A "bunch" clearly is 8: QED

And even if you had, it would likely not be large enough to hold this shark. @goranngreat image. The RASA/ZWO combination keeps on delivering.

It's a cgs unit. (Just adding another dimension to the discussion )

Mainly, only up to a certain age, or in passports.