rickwayne

+1 on Stellarium. Since I use KStars/Ekos to drive my scope it would be simpler to just use it to previsualize, but the UI is clunkier -- for example to rotate the FOV symbol, you have to go through a menu entry and type in a number, where with Stellarium it's just a single click to rotate some number of degrees. I also don't run KStars with background imagery on my scope-mounted Pi, that makes it kinda laggy. One advantage to the folks running their scopes with laptops or more high-powered machines.

I'd say it's full-auto these days, unless you want it to turn the AZ and ALT knobs. I mean, yes, you have to choose a star, then click "Next", then click "Refresh". Seems pretty automated to me! I've had very good results with it slewing the scope and shooting its images automatically, even pointing 170 degrees away from Polaris.

Frankly I'd try it unfiltered. Why not collect all the photons you can? Any filter will invariably affect the color balance of your images. Narrowband is something else again.

There may be a category error here. Wim's link is for INDI drivers for the camera from which yours was copied, i.e., the software that mediates between generic camera commands to the INDI platform running on Linux and the specific data to be sent over the USB wire to your camera to make it happen. For example "open the shutter" might be part of the standard INDI command set, but different cameras might expect completely different characters coming over the USB link to make that happen. The camera's firmware is the stuff internal to the camera which actually runs it. It's stored in non-volatile memory on chips inside the camera. Updating that is completely manufacturer-dependent, invariably it is done with a bespoke program from the vendor, often as not only provided for a single platform. I mean no disrespect to your choices, and I get that you're not working with James Webb-size budgets here. But the 120MC -- I own one, as it happens -- is going to be a pretty challenging imaging camera for a beginner. The chip is tiny, so the field of view is too, which exacerbates all kinds of beginner problems such as finding the target in the first place. For planets (and here I am talking well outside my area of experience), a tiny chip is fine because the planet's image is too. For deep sky, not so much -- a tiny field of view is pretty much the same as saying "huge magnification" for visual. Every tiny flaw in your mount's tracking, polar alignment, wind blowing on the rig, trucks driving by...all of that will conspire to make it hard to get sharp images. It's why we so often counsel beginners to start with a small wide-field refractor, they're much more forgiving while you're learning the craft. (It's not as big a deal for planets because they're brilliantly sunlit objects, so long exposure times aren't needed.) Do you have a DSLR or interchangeable-lens compact, by any chance? For deep-sky, that would be a better choice IMO. Not to despair about the T7c, if you ever do get it working it'll make a great little guide camera (that's what I use my 120MC for).

Concur with Vlaiv. At that budget, my (free) advice is don't even think about a telescope, put every penny you can scrape into a mount and put a DSLR+lens on it. Even at 50mm, there are excellent targets that will give you plenty of challenges. In the winter, the Orion Molecular Cloud Complex is bright, colorful, and ranges from stuff you can pick out with the naked eye (M42) to regions that require lots of total exposure time (Barnard's Loop, the Witch Head Nebula). In the summer, there are excellent pickings in the Milky Way, e.g. the Antares/Rho Ophiuchi region. There are also lots of targets in the 100-200mm range, if you don't already have something in that range you can pick up an old manual-everything prime for around a hundred bucks if you look. (Can't use autofocus, prime is better for astro than zoom, camera automation does you no good...heck, a 1970s vintage screw-on Pentax with an adapter would serve you nicely.) Many people starting out think it's all about the optics. For deep-sky photography, that's really not true unless your goal is tiny galaxies. What's vastly more important is a mount that will track well enough to let you consistently obtain anywhere from 30 to 120 seconds in your exposures. (For tiny galaxies, you need long-focal-length optics AND a good mount.) If the mount wobbles, it doesn't matter how great your optical train is, the pictures will be blurry at best and an utter hash at worst. You might be able to get a telescope package for that much, even something with a motorized drive. But there is just no way to make a profit selling a sufficiently high-quality mount for deep-sky astro for a couple hundred bucks. Otherwise the market would be full of them. For my work, at a mere 336mm, the mount has to track within a fraction of an arcsecond, so less than 1/3600 of a degree, for the picture to come out. A quality tracker, DSLR, and decent lens will give you the whole deep-sky experience. There will be a LOT to learn and many challenges along the way, not the least being processing your images.

If you want a complete introduction to deep-sky imaging, from the very basics of how sensors work on up through telescopes and processing, I heartily recommend Charlie Bracken's The Deep-Sky Imaging Primer.

Are you using a computer to run your camera? If so, look into plate solving. Even without goto, it really helps to know the precise coordinates of the center of your field of view.

Ahh, yes, very good point. APP has star reduction/elimination now but I haven't made that work well for me so I just use starnet++ on the command line. And I bought Topaz Denoise for terrestrial work, that's pretty magic if you use it with a light touch. I am hoping that Mabula will build this stuff in before I'm too old to haul my CEM70 around. I've thought about volunteering as a developer for him once I retire. The old mythical man-month thing, adding another programmer doesn't always speed up a project but he could shovel off a lot of the scut work onto me. 🙂

I use Photoshop for all my photography, including terrestrial stuff. So I would miss it if I didn't have it for astro. That said, the pixel editing is the most generic part of astro processing, really any capable photo editor will do. The calibration, stacking, light pollution/gradient removal, color calibration, and stretching are harder to reproduce with generic tools. Both PixInsight and APP offer 30-day trial downloads. APP is a LOT simpler to learn in that time, and although it doesn't have the range of features or quite the power of PI, IMO most folks will get better results sooner. Daf, what features are in StarTools or Affinity that APP lacks? Not trying to start an argument, I promise! I just want to know what I'm missing.

Agree. I wouldn't go any contrastier than that, I have a fatal weakness myself for toppling into "garish". You didn't say what you were using for processing but I'll make my by-now-standard pitch for Astro Pixel Processor here. It is AMAZEBALLS at removing gradients and light pollution, and you needn't have a physics PhD to use it.

Yep. That's even an issue for astro autofocus setups -- if the stars aren't looking like fairly small discs, the system doesn't get any traction on them. Since focus for the Moon is the same as for stars, the Bahtinov mask technique works quite well. It really does make it easier to fine-tune your focus. Then you can slew to your target and go nuts.

Unfortunately the usual deep-sky road really is steep and rocky without a good mount, and good mounts are just expensive by the nature of the beast -- it's extremely difficult to build something with sub-arcsecond mechanical precision that will carry kilograms of load without expensive tooling and expensive materials. Toss in the small production runs, and you've a recipe for high prices. Once you get beyond camera-lens focal lengths, you're invariably talking something heavier, requiring a more robust mount to carry it precisely, and larger, with a higher moment of inertia, requiring more powerful motors to move it precisely, as well as the added magnification which makes any tiny error apparent. Do people manage it? Yes, and they're rock stars. Or they image for 20 hours and throw out 80% of their frames (sort of a lucky-imaging-writ-large strategy). I would not presume to tell you what you want to do. But I would advise you that too much scope for the mount is a hallowed old cliche of new astrophotographers. There are a lot of 300mm targets in the sky; I certainly haven't run out in the three years since I got my Stellarvue. If you're getting consistent two-minute exposures at 300mm, you've got the keys to a great deal of the kingdom. Narrowband read noise would present a challenge, to be sure, but I bet you could pull off even that.

Nice! Single frame, right?

Assuming that the line to the left of the knurled wheel is the back of the flattener, yes.

I can't look at that thing for more than a few seconds without getting dizzy!

Definitely want to look at a single sub. Also this example of incorrect-backfocus artifacts may be helpful: https://cdn.shopify.com/s/files/1/1594/4815/files/Back_Focus_Spacing_Guide_1024x1024.jpg?v=1606528627

I confess that when I saw this thread's title, my first thought was "Well there's your trouble. Always set your dew straps on 'gentle warmth', frankly I don't know why they even include the 'fire' setting".

Thank you. Being a US Midwesterner, I have to respond by pointing out that I haven't fixed my incorrect-backfocus distance so the stars in the corners are terrible (e.g. lower right, where it hasn't been cropped). But I really like it too.

I was thinking about the 45-minute drive out to my favorite dark site...with work in the morning...ugh. Then I realized that the Veil was going to be visible all night within the narrow window of sky provided by my back yard. The CEM70 delivered about 0.6" or better all four hours; processing (Astro Pixel Processor HSO 2, starnet++, Topaz Denoise, Photoshop) was super-easy. As the old Honda commercial said, "Isn't it great when things just...work?"

This is quite possibly my favorite astro fail of all time -- and I speak as someone who has had smoke coming out of their mount. I salute you, sir!

When I did the Soul in Ha/OIII I tried and tried to get the blue OIII but it always came out crappy. So I sat down with the color image and the OIII mono and just hand-tinted it blue where the OIII was brightest. That image always has to come with a disclaimer.

If you don't mind the whole slow-boat-from-China thing, there's an AliExpress vendor called "telescope & accessories" who offers nice metal Bahtinov masks. But you might have to think of a way to hang it on your scope, it's only designed for 100mm diameter lenses/scopes.

This area is pretty shot with stars, it's easy to let them swamp the nebulosity you're trying to show.

Olly, forgive me if you already knew this but he was using the DARV technique, where you slew in RA during an exposure, out and back, to make a deliberate star trail. If the mount is perfectly aligned, there will be no DEC drift during the exposure and so the incoming trail will be the same as the outgoing, leading to just a single line. If there is DEC drift, the two trails will form a "V" shape. D.A.R.V (Drift Alignment by Robert Vice) - Articles - Articles - Articles - Cloudy Nights All that you say about aligning the camera axis and figuring out which direction is which on the sensor applies, of course. Obviously, DARV doesn't give you any information about how your RA axis is doing.

If you're going to try to select with a complex border such as foliage, I can heartily recommend Topaz ReMask. There are probably other tools that do the same thing but this one makes it super-simple. You just paint the border with a fairly wide brush and it computes a mask for you. It also has tools for refining the mask if the algorithm doesn't get it quite right (too greedy or too lazy).