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Arp 217, aka ngc 3310, is a galaxy in the constellation of Ursa Major. It has a very active nucleus with a small ring structure which is only 6" x 9" in angular size. This ring is most likely the result of galactic cannibalism, in which ngc 3310 has devoured a smaller galaxy. ( https://ui.adsabs.harvard.edu/abs/1981A%26A....96..271B/abstract ) The galaxy also has a one sided jet emanating from its centre. This jet is possibly caused by a recoiling black hole sending out radiation and matter. Where the jet passes, it triggers violent star formation. ( https://ui.adsabs.harvard.edu/abs/1984MNRAS.207...47B/abstract ) In this image, the jet is the straight but irregular feature going from the centre of the galaxy towards the upper right corner. Ngc 3310 has several tidal streams, which are just barely visible in this image. (One loop stretches towards the upper left corner, about the same diameter as the central, bright region of the galaxy.) Technical data: 11.4 hours of integation time in Ha, L, R, G, and B, of which 4 hrs L, and 4 hrs Ha I collected the data back in 2019. Telescope: SW MN190 Camera: ZWO ASI174MM-Cool Processed in PixInsight

Should be ok. Do you have a focusmotor or do you focus by hand? If the latter, it's probably easier to use live view on the camera.

I use a bahtinov mask for focusing. Just get a bright star in the fov of your guide camera. If you have an off axis guider, first focus the main camera, then the guide camera.

Not me. Although I do have my own little observatory.

I don't do much visual astronomy. But my guess is that a small refractor (80 mm) at a dark site will give you more joy than a larger (150 mm/6") reflector at a light polluted site. The best telescope is not necessarily the largest, but the one you enjoy using, and use more.

You won't regret it. On my handheld screen the background looks a bit green. Try scnr (processes >> noise reduction) with standard settings.

If you don’t have a car and need to walk or use public transport, I’d strongly recommend to start with a refractor and an alt-az mount with tripod that fit in a back pack. But do visit a local club to see what can work for you.

Indeed. I ordered a FT focuser for my MakNewt last August. After months of delays and email correspondence with the retailer (astroshop), I canceled that order a few weeks ago, and ordered the Omegon 2" Steeltrail instead. By adding just € 65 to the original order I now have a stable, working focuser with a Pegasus Astro FocusCube and a Pegasus Astro Powerbox Advance. I read on CN about the hard times that Starlight Instruments is experiencing, plus that their patents are about to expire (not sure if that's true). Asian focuser manufacturers are catching up quick, giving SI serious competition.

What you write about here are more likely collimators or collimator caps. Those are needed to align the optical elements in your telescope (tube, primary and secondary mirror, and focuser). Collimation is what you do once every season (unless you move your scope around a lot). A coma corrector is a permanent part of your imaging train. What I mean is this https://www.firstlightoptics.com/coma-correctors.html Your telescope may need collimation, which can correct (some of) the tilt. You can easily check if it does in the following way. Centre your scope on a fairly bright star (Polaris will do). Focus the telescope and make sure that the star is properly centred. Defocus the star untill you see the doughnut shape. Take an image that is not over exposed, ie the star should not be blown out. Move the focuser past best focus and defocus an equal amount "on the other side" of best focus. Take a new image. If the doughnut ring is even and symmetric in both images, the optics are aligned. If the dark centre of the doughnut is more on one side, alignment is off, and you will need to collimate. Collimating an f/5 Newtonian is a bit fiddly first time you do it, but it's not too difficult. There are many guides online. You only need a few tools.

yes Here are sections from your image, taken from each corner, the middle of each side, and the centre of the image. You can see the distorted stars in the corners, especially the right hand side. The stars are a lot smaller in the centre part of the image. Also, the bright star in the lower right corner (main image in my previous reply) has double diffraction spikes. This is caused by either it being a double star (which it isn't) or poor focus. This is a clear indication of tilt.

Here's my result, using PixInsight. Most of the process steps that I used are available in PS - cropping to get rid of stacking edges - Gradient removal (DBE in PixInsight), two passes - Background neutralisation. Use the eyedrop colour picker in PS? - Photometric colour calibration - BlurXterminator - Histogram transformation, equivalent to levels in PS - Colour saturation. Increase overal colour saturation. Then with a lightness mask, protecting the galaxy and stars, decrease saturation in the background - Noise reduction (NoiseXterminator) A cropped version less compressed, with colour punch

I also downloaded your stacked image. Imo, the data is good, but as said before, you really need to take flats. What's more, you should invest in a good coma corrector. As it is, you have very strong coma, especially on the right hand side. The uneven distribution of coma hints at tilt in the imaging train. There is some "walking noise" in your image, which you can avoid by dithering. This is a setting you can activate in PHD guiding. Try to dither 10 - 15 pixels on your imaging camera (about 10 arc seconds)

That would make it equivalent to a star adventurer or similar star tracker. So yes, it's a viable budget solution. You won't have goto capabilities, and you need to make sure you have good polar alignment for astrophotography.

Thanks. I'm sure you'll find it. @gorann found it in his data.

You need averted vision ( 🙃 😉 ) or a computer screen to see it. Handheld devices just have too little dynamic range. A dwarf galaxy 20 Mly distant and almost eclipsed by a star, is faint by any measure. On my computer screen it's clearly visible, but on my Samsung Galaxy Tab, I can only just about see it because I know it's there. I'll post an inverted luminance image.

It really is. Here's a slightly enhanced version. I want to avoid at all cost "painting" in the structure, or use elaborate masks to selectively lighten areas. In this version, I used a simple mask to protect the stars and M31, and applied Multiscale processing to enhance the galaxy

Andromeda IV must be the most imaged but at the same time least seen galaxy out there. It is right next to the Andromeda galaxy, but being a dwarf, and being very faint, it is rarely noticed. Here it gets centre stage, flanked by another dwarf galaxy (but this one with its own Messier number), and a star cluster. I believe it was an image or video by Adam Block that brought this dwarf galaxy to my attention. You would think that this galaxy is part of the Andromeda system, but in fact, the dwarf is about 20 million light years distant, well beyond, and not at all tied to M31. So, it shouldn't even have an "And" number. The galaxy was discovered by Sydney van den Bergh in 1972. Data for this image was collected back in January, and consists of 6 x 5 minutes for G and B, and 11 x 5 minutes for R, as well as 21 x 3 minutes L, a total of about 3 hours of integration time. Gear: SW 190MN telescope and ZWO ASI294MM camera An inverted L version showing the very faint dwarf.

Välkommen till SGL.

The c8 is a slow scope, so you need long exposures. For that to work, you need good guiding (ideally a guide error less than half your imaging "/pixel). That's going to be a big step up from a star adventurer and a 50 mm lens. As @Albir phil wrote, you may get more out of a small refractor, 70 - 90 mm at f/6 or so. Then when you've learned the basics, you can always put your c8 on the mount. Either way, what do you intend to photograph? Nebulae or galaxies? Galaxies require a longer focal length and lower "/pixel than nebulae.

Tell me about it! It's especially noticable May through August, when Göran keeps his observatories closed. During the same period, the sky is a lot brighter here.

Excellent. As a bonus, you also got the small Ha region in the galaxy near the bottom right corner.

Very nice images, both. I like the overall cooler colour in the new version, with more blue in the arms. That Ha knot on the left side is distinctly different. Also, the new version lacks the Ha-"jets" coming out of the galaxy. I'm a bit surprised that that doesn't show in the new version.

I always believed that Seeing affects FWHM (you know you've been doing astrophotography for too long, when the first that comes to mind is ...) 😉

Thanks for the tip.I had already thought of replacing the one that is in the way with a hex bolt. I just have to check the size/pitch.

I did a bit of testing this night. Collimation is as good as it will ever get. Slightly defocused stars look very symmetric. Also, the background is more even before any image calibration than it was before. No more dodgy stars in one corner. A FWHM/Eccentricity map still shows a very small amount of tilt, but I can address that tomorrow, and it isn't noticable in an image. The focuser and power box do their job. Next step is to dial in the best settings for the autofocus routine in Ekos.