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I took the plunge and replaced the stock focuser on my Mak-Newt. I wasn't pleased with the low profile Crayford focuser because of the floppy extension tube. While I was able to fix it in place by locking the thumb screw, I almost had to use pliers to do so. Imo, this is a poor design for an imaging rig. On the other hand, replacing the focuser on the 190MN is a bit of a gamble as people have failed before, and messed up collimation beyond all hope. There are two focusers that are "drop in" replacements for the stock focuser, that I'm aware of, MoonLite and Feather Touch. Both can be mounted on the stock base plate without modifications, although they both do need adapters. I went for the more expensive of the two: Feather Touch FTF2020BCR with 2" barrel and 2" travel. I ordered the focuser in August of last year from Astroshop. The delivery date for the focuser was pushed further and furher into the future, and after reading on CN that the founder had passed away, and that the second person was no longer with the company, I decided to cancel my order and go for another focuser alltogether. The Omegon Steeltrail 2" is a very low profile focuser that fits in the baseplate of the 190MN without any modifications. Or so I thought. The diameter of the dovetail is 78 mm, the same as that of the stock focuser. No problem there. But the Omegon has such a low build height (46 mm), that the focuser knob's edge is below the edge of the housing. This means that when the draw tube is all the way out, the focuser can't stand flat on a surface. It will rest on the knobs and the edge of the base that is furthest away from the knobs. Since the focuser will be mounted on a tube, that may not be much of a problem, but unfortunately, the dual speed knob is closer to the focuser housing than the singel speed knob, and it doesn't clear the stock focuser's base plate. In order to be able to mount it, I had to cut a ring from gasket paper to get the clearance I needed (2 x 0.8 mm gave me just shy of a mm clearance). Because the Omegon is a lot (!!) cheaper than a Feather Touch (290 € vs 900 €), I could afford a focus motor and a Pegasus Powerbox Focuser with shim between housing and base plate. Note the clearance of the focus cube over the tube. Phew! Focuser orientation needed to get clearance. (Btw, the pads on the camera are vibration dampeners. The camera fan on some ZWO cameras is known to be a source of vibration). Never mind the cables, I will clean that up before the start of astro season in late August. To get the focus cube bracket where I wanted it, I had to use washers. Without the washers, I'd have to use the last slot in the bracket to attach the focus cube to the focuser. But then the axle of the motor wouldn't fit all the way into the coupler. Thumb screw clearance. When the focuser is all the way in, this screw pushes against the bracket. I may have to replace it at some point, but for now, I have set the zero position of the focuser to this distance. Pegasus Powerbox Advanced The old "power boxes" and usb hub. To the right, the 12V distribution box, and in the middle, the 5V distribution box. The powered usb hub is also no longer needed. When I used a Rock64 SBC with Ekos, I had to connect my imaging camera through this usb hub, or it would crash the system. With the RPi 4, this hub was no longer neede, but I kept it so as not to alter balance.

Nine months ago I ordered a replacement focuser for my Mak-Newt (190MN) from astroshop. The stock focuser (low profile dual speed crayford) has a built in extension tube which I wasn’t pleased with, as it introduces play in the imaging train. AfaIk, there are only two replacement focusers for this scope, MoonLite and FeatherTouch. I went for the FeatherTouch focuser with adapter ring. The focuser was not in stock and the lead time a few months. A few months became a few months more. And more. And more. About two weeks ago, astroshop informed me that the earliest possible delivery date had been pushed forward to no earlier than 1 August. In the mean time I had read on CN that the owner of Starlight Instruments (manufacturer of FeatherTouch) had past away in 2021, and the second most experienced person was no longer with the company. I decided to cancel my order and order the Omegon Steeltrail 2” instead. The balance I had with astroshop allowed me to also buy a Pegasus Astro focuscube and a powerbox advance. Such is the cost of a FeatherTouch. (I had to pay an extra 65 € for the new order.) Last wednesday the postman delivered this I just posted a write up of the installation

Can you redo the polar alignment routine where both axes worked? If that still works, I’d say a software issue is the more likely cause. You can also check under the hood if cable connectors etc are ok.

@Rodd which program do you use for stacking? If PI, consider usong the autocrop function of wbpp. As @The Lazy Astronomer noted, there is a soft edge in your images that may be caused by stacking. Autocrop in wbpp will deal with that. That can explain it. I always blink subs before stacking and remove those that are too "thin", ie when I see a loss in contrast between the object and the background. I've at several occasions, thrown away whole nights worth of data because of lack of contrast. Such is AP in temperate climates.

Btw, the background of the L400 image is (after DBE) very flat. here is the superstretched inverted image.

Not necessarily strange at all. With a slower scope, dust bunnies that are further away from the sensor can still be picked up. Dust on the camera front glass is picked up by most telescopes, but dust on filters only by slow ones. Btw, I processed your image in PI and find it quite a pleasure to work with. The L has great detail. The colour data was a bit "thinner". I don't know if you should adjust the exposure time or camera gain for RGB. Anyway, here's my result. On my screen, the background is still uneven, but otoh, it seems that my screen is very unforgiving in that respect. I've seen a lot worse in images processed by professionals. All in all, great data to work with.

Very nice image. Adding more data would of course allow for a better definition of the galaxies. But remember that to get a significant improvement from what you already have, you need to roughly double the integration time.

If you can get the same result in much shorter time, isn’t that an indication of improvement?

Yes, more than I expected. Go for it! It's not a difficult target as far as data capture is concerned. Just process it with a gentle touch.

Thank you, all. Much appreciated.

From the ESA flicker page: "Many of the best-loved galaxies in the cosmos are remarkably large, close, massive, bright, or beautiful, often with an unusual or intriguing structure or history. However, it takes all kinds to make a Universe [...]. Messier 110 may not look like much, but it is a fascinating near neighbour of our home galaxy, and an unusual example of its type. It is a member of the Local Group, a gathering of galaxies comprising the Milky Way and a number of the galaxies closest to it. Specifically, Messier 110 is one of the many satellite galaxies encircling the Andromeda Galaxy, the nearest major galaxy to our own, and is classified as a dwarf elliptical galaxy, meaning that it has a smooth and almost featureless structure. Elliptical galaxies lack arms and notable pockets of star formation — both characteristic features of spiral galaxies. Dwarf ellipticals are quite common in groups and clusters of galaxies, and are often satellites of larger galaxies. Because they lack stellar nurseries and contain mostly old stars, elliptical galaxies are often considered ‘dead’ when compared to their spiral relatives. However, astronomers have spotted signs of a population of young, blue stars at the centre of Messier 110 — hinting that it may not be so dead after all." https://www.flickr.com/photos/europeanspaceagency/48763200193/ I collected the data for this image back in 2018. New processing skills and new procedures in PixInsight, allowed me to reveal the blue core of M110. Particularly, the use of SPCC colour calibration uses the surrounding Milky Way stars for white reference, rather than the main target of the image. Luminance detail was enhanced with Multiscale Median Transformation in PI Gear used: SkyWatcher 150PDS on a SkyWatcher AZ-EQ6 mount ZWO ASI174MM-Cool (yes, they did sell a cooled version of this camera. It's a shame they don't sell a cooled version of the ASI482) Total integration time: 5 hrs 44 mins (3 x 20 x 3 mins RGB, 82 x 2 mins L)

If I were you, I'd look into the ASI 432MM, 482MC, or 294MM/MC. Of these, only the 294 has a cooled version. The 432MM and 294MM come in monochrome versions, and the 482MC and 294MC are osc cameras. Osc cameras can be deBayered in super pixelmode. The 432 has 9 um pixels, the 482 5.8 um, and the 294 has 4.63 um pixels. Actually, the latter has 2.315 um pixels, but, the osc version has them binned already to 4.63 um size, and the MM version is recommended to be binned. If you go for a non cooled camera (cheaper), a model that doesn't have amp glow is always better. Cameras that have amp glow need matching darks, which is more difficult to achieve with non cooled cameras. If you want a mono camera, you will also need to invest in a filter wheel, and filters. Any cooled mono camera will break your budget, with maybe one exception. ZWO used to have a cooled version of the ASI174MM, but it is now discontinued. QHY still markets their model, I believe, and so may other manufacturers. Cameras such as the 174 or 482 have pixel sizes that put them in your "sweet spot" at 1000 mm fl. Both the 174 and 294 have amp glow that needs careful calibration, and I'm not sure if the non cooled versions will work for dso imaging, because of that.

A friend who runs his setup remotely from my observatory, uses SGP. I use Ekos/Kstars. I find his user interface the most counterintuitive and unstructured I've ever seen. I guess it's all in the eyes of the beholder. Once you get to know a/any software package, it seems simple and straight forward. But for an outsider it may be anything but that. Btw, this is not meant as any criticism of SGP, but rather an observation on user interfaces and how we perceive them.

I stand corrected. I don’t have the eq5, but I had a vague memory of reading somewhere that it had. Good thing you corrected that.

Astroberry is a single installation package, where all the dependencies for Kstars are provided. Also, the hardware is stable. I have used Rock64 sbc's with Ekos/Kstars, but sooner or later I have always had some issues. For example, with a Rock64 I need to connect my ZWO camera through a powered usb-hub, despite having a Meanwell 75 W power supply. There have been intermittent problems with character sets in the software, etc. RPi is just more mature and stable, imo. What drew me to other sbc's was, at that time, that they provided a usb3 port, and usb was not shared with wifi. The emmc memory is also more stable and faster than a sd card.

Ekos/Kstars for me. This season, I’ve had only one session where it had stopped working unexpectedly. And I had to reset the pointing model once, because of meridian flip errors. Other than those two mishaps, it just worked.

With 3.76 um pixel size and a 430 mm focal length, you need good seeing to benefit from drizzle. The downside is the much larger file size, as well as some loss in snr.

August 2021 I bought a small "APO" refractor with built in field flattener. I never really got on with it, and after a few tries I've only used it for capturing spectra (star analyser 100) and star clusters in order to create colour-magnitude diagrams. In september or october 2021 I collected the data for this image of M31. Maybe I didn't refocus between filters, but the stars had terrible blue halos, and I wasn't too pleased with the star profiles either. Now, with the help of Russel Croman's XTerminator tools, I can finally get an image that is presentable. This is 4 hours of RGB data with the TSED70Q and ASI294MM camera. Processed in PixInsight with most of the XT's

I've had a closer look at the objects in this image, and found a few interesting facts. I edited the original post and added references

Thank you, Steve. That small galaxy isn't even catalogued, but guessing from its size in the image, and information on similar galaxies, I'd say that it's between 300 and 500 Mly distant. That is not as far away as the galaxy tagged as J0150+2725. That galaxy is more than 4 billion light years distant. Four billion years ago, the solar system was in its infancy. The galaxies that are furthest away and still identifiable in my image, are near the top edge. A small galaxy cluster that is just visible as red diffuse patches is 6.8 billion light years distant. When the light that is recorded in the image left that cluster, what would eventually become the sun was still a cloud of hydrogen. The cloud slowly increased in density and temperature, until a star was born. Truly mind boggling.

Finding the right parameters takes most of the time. For conventional deconvolution you also need to create a psf, a star mask and a strong luminance mask. BXT only needs a psf, after which it can sharpen detail much closer to the background/noise floor.

Yesterday I reprocessed an image from november 2021. It features ngc 672, ic 1727, some smaller galaxies, and an asterism. With the new Xterminator tools, I was able to pull out more detail. Afterwards I researched the objects in the image, and found an article describing a gravitational lens which was in the field of view. The galaxy tagged as J0150+2725 is the lensing galaxy. The galaxy itself is approximately 4.5 billion light years distant. It acts as a gravitational lens for one or several galaxies that are three times as far away. A study with the Hubble Telescope has shown that the lensed galaxy has a red shift of 1.08. The lensed galaxy is of course not visible in this image. Or is it? Some of the red fuzzy patches around J0150+2725 are indicated in the mentioned study. But it's not clear to me if these are in fact lensed galaxies. https://iopscience.iop.org/article/10.3847/1538-4365/ab5f13/pdf Near the top of the image is the faintest and most distant galaxy cluster I have ever captured. In the yellow circle is galaxy cluster RM J014914.9+273706.1. The galaxies in this cluster have a red shift of 0.506, which puts them at 6.8 billion light years distant. The light that was captured for this image, left those galaxies when what would become our sun, was still a cloud of hydrogen atoms, slowly growing denser and hotter. There are several quasars in this image, I have only tagged the ones with a red shift of approximately 2 and higher. Several others with red shifts between 1.2 - 1.6 are strewn across the field of view. J014947.9+271728 is a candidate subdwarf star. Subdwarf stars are hot, blue stars that are less luminous than main sequence blue stars. These stars are burning Helium. "To end up on the EHB, stars have to lose almost their entire hydrogen envelopes in the red-giant phase, most likely via binary mass transfer. Consequently, hot subdwarfs have turned out to be important objects to study close binary interactions and their companions can be substellar objects such as brown dwarfs, all kinds of main sequence stars, white dwarfs, and maybe even neutron stars or black holes." https://www.aanda.org/articles/aa/full_html/2019/01/aa34236-18/aa34236-18.html Here's the annotated version Technical details: 145 x 4 minutes RGB exposures (580 minutes total), taken with my 190MN and ASI294MM Processed in PixInsight. Next season I'll revisit this area and collect more data, including H-alpha. i think that both the larger galaxies have H-alpha knots that would really make this image even more interesting.

Very nice. You even got the H-alpha arc (shock bow?)

This image shows the Ha regions a little better. https://www.astrobin.com/89774/B/

I only apply deconvolution in areas that have a high SNR, ie bright parts. So the exact noise distribution should be of minor concern. While it is possible to use deconvolution without a mask, and use the regularisation parameters to control the process in low SNR areas, I take the easy way out and mask off low SNR areas.