ONIKKINEN

It depends on the sensor used where the ideal range of ISOs is. Sensors usually have a point where increasing ISO decreases full well capacity significantly but no longer reduces read noise as much. At that point its pointless to increase ISO as it will just saturate stars earlier but offer no benefit of significant value. There is also this misconception that DSLR images should have a specific looking histogram or that the subs themselves should look good and show the target clearly. That is not necessary, the only thing deciding whether a sub is long enough is the amount of electrons in it, not the ADUs or histogram shape and placement. You get a brighter image by increasing ISO past the optimal point but it will still have more or less the same SNR as an exposure of the same length with one setting lower of an ISO.

Without a specific budget its difficult to advice. If you can, get an EQ6 and the best scope you can afford after that. If youre writing a website with scope advice it should also be bracketed into budget categories as no one scope can fit all purposes on all budgets. Beginners reading that article should walk away from reading it with the knowledge of mount 1st, mount 2nd, mount 3rd and then maybe start thinking whats left to buy a scope. You can always upgrade a cheap initial beginner doublet for a better scope but a bad mount will be bad forever and only a waste of time and money in the long run. But my 2 cents on a scope that does a bit of everything would be an 8 inch newtonian on an EQ6. Aperture to cost ratio is very good, unlike apochromat refractors (but there is a catch, of course). Will require plenty of elbow grease and/or further investment into upgrades to bring a factory standard newtonian up to demanding imaging spec, but its not something you necessarily have to do right away. For example i have spent maybe 1800€ on upgrading my VX8 with a carbon tube, focuser, secondary spider, corrector, rings and plate, to bring it to astrograph standard. At this price point its comparable in price to triplet apochromats with half the aperture. You could substitute half of what i spent with DIY if needed so the deal only gets better.

Excellent, love seeing these kinds of images even if they dont have the visual awe of a shiny nebula or a nearby galaxy. Some real sense of scale with the giant galaxy cluster appearing as a small faint grouping of fuzzies, truly unthinkable distances here. Regarding StarX accidentally removing the faint fuzzies, you could manually add them back to the starless layer and include those in a further stretch to lift them up behind the much brighter stars. I tried that with an image of the coma cluster i took last spring, took a couple of hours to sift through the hundreds of galaxies and manually erase them from the star-layer to add that back in to the starless layer (with some subtract and screen etc, you get the idea). "fixed" starless layer of my experiment below: 90% of these are removed with StarX and appear in the stars-only layer. Never processed it fully and just did it as a proof of concept, looks like your faint fuzzies could benefit a little from the same treatment.

You could try stopping down the lens to try and curb the aberrations of your stars, but not much to do about them after they have already been captured. You could also crop a bit inwards to hide the worst effected edges of course, but short of that an aberrated star is an aberrated star.(BlurXterminator, an AI tool just released, which may fix this but its a more advanced topic requiring PixInsight to work). For Photometric Colour Calibration you need to know a few things. Below a screenshot to illustrate a few things. In the search bar you can search the object of your image and it will fill in the Right Ascension and Declination coordinates correctly. You need to have this object be near the center of the image which i think your M31 is not, at least not close enough since its a very wide field image. You may need to manually input the coordinates or choose a star close to the center of the image as the reference (you need to browse Stellarium and find out an HD-something-something number of a star and search that for example). You also need to know the focal length and the pixel size used for capturing. The stated focal lengths and pixel sizes are rarely exact and these values need to be pretty close, so try a bit under and over the focal length you thought you captured at, so for example maybe try 70, 75, 85, 90 and see if those work. Note that if you have resized the image before doing this step these variables have changed and you need to change pixel size/focal length accordingly. Here with this image you may run into a problem, Siril PCC expects a telescope sized image and may not work for very wide fields where it has trouble picking up stars used for the calibration. So it may be possible that it will just not work for your image. If you get an error that it didn't work, try with another Photometric Star Catalogue, if still doesn't work then maybe it just wont work for this image. You might want to try more with this lens before investing into more gear. What you have here is basically a snapshot, a very short peek into what the skies will give you, try gathering at least a few hours on some target and work with that. You may be surprised how much you can get out of a cheap lens if you accept the limitations in sharpness/stop down the lens and accept the limitations that come with that.

Warranty repairs are very much possible and the customer service rep (Eddy if i recall) is active and reachable through AliExpress messages or Whatsapp. Of course you'll have to ship it to China which will cost something and probably take a while to get sorted. That is the obvious downside and why i linked the 2 versions available from TS in Germany where you can assume to have effortless warranty repairs if needed as its much closer to home and a shop many have dealt with dozens of times. Regarding VAT, here is what the site tells to me when i VPN to the UK (or just change the location in the toolbar above) My shown price with VAT included (to Finland): Price shown to me as if i was a UK shopper: Comparing the prices it does look like UK customers will pay VAT when it is imported since it does not mention anything about VAT and the price is cheaper.

You can save an enormous pile of money by getting the Rising Cam branded IMX571 chipped OSC camera: https://www.aliexpress.com/item/4001359313736.html?spm=a2g0o.productlist.0.0.6f047164JGhOx6&algo_pvid=88c7fc7f-59b2-4b58-9bdc-a75b08237944&algo_exp_id=88c7fc7f-59b2-4b58-9bdc-a75b08237944-0 Performance is the same (actually a bit better with lower read noise) than the 2600MC. No Asiair with this camera, but with the price difference between the RisingCam and the ZWO 2600MC you could fit a mini-pc and still be left with pocket change in the end. This camera has many happy users around the world and the paying/shipping process is painless so no need to worry about it being an AliExpress thing. The manufacturer is ToupTek, which makes all Altair cameras for example, but just without the Altair price. You can expect a high quality product and not some knock-off cheap chinese copy. If AliExpress is not your thing, you can find the same camera (with extra price) here: https://www.teleskop-express.de/shop/product_info.php/info/p14967_TS-Optics-Color-Astro-Camera-2600CP-Sony-IMX571-Sensor-D-28-3-mm.html Or here: https://www.teleskop-express.de/shop/product_info.php/info/p13286_Omegon-Camera-veTEC-571-C-Color-cooled--Sensor-D-28-3-mm.html Even if you already had an Asiair (not sure if the case) you would still be saving money with these compared to the 2600MC. 294 is a sensor to avoid in my opinion. Seen too many threads about calibration issues with that one.

Looks like the same mount as the one in an Astromaster 130, so i am afraid completely useless and not much you can do to make the wobbles go away short of mounting the scope on something else.

This is so crazy how much it improved the original that i thought was already pretty good. Not only is the improvement but also i cant see any negatives from the tool. Doesn't look quite as detailed as a planetary image with this aperture in excellent conditions so i wager there is still ways to go before we get into the realm of too much detail for the aperture. Gotta jump on the PI gravy train now.

If you have a multimeter you may want to check the voltage after its been in use in the cold for a while. Its likely it only supplied 11-12v at the end of the night even if it still had most of ita charge left which would affect tracking rates. Cold does that to unregulated batteries, no way around it. Li-ion and other more expensive types are a bit better but still only half a solution. For optimal use you want the voltage to remain between 13-14v, below 12v you run into issues and below 11v your stepper motors will start to slip completely and so it looks like guiding is failing when in reality the guide impulse was never completed by the motors.

Its getting really difficult to resist getting PI based on the results so far. Looks like a TopazAI but built for AP from the ground up so fixes the "Topazed" look of that tool.

Skywatcher uses terrible grease in their mounts that doesnt like sub zero temperatures. Could have taken a while to get sticky and when it did your guiding remained bad for the rest of the night. If youre up to a little DIY you would benefit from cleaning the factory gunk and replacing it with a nice white PTFE grease (super lube is great) that doesnt mind the cold. * Or power supply issues if you run with batteries not suited for cold.

This has happened to me but in -20 or so weather (45 degree difference in adjustment and use temperature). I had just set my mounts backlash to be perfect so that it barely clears all the tight spots all around the DEC worm. Lo and behold couple hours later in the cold it did not move and i had to relieve the backlash setting a bit to make it work.

None of the dust motes you see here are on the scope itself, the optical elements are simply too far away for dust motes on them to cast shadows this small. Dust on the front meniscus lens, primary and secondary will be invisible on the sensor so cleaning them wont fix this. These are almost certainly on the sensor window itself, or at the furthest on a filter (if you have one) within a few centimeters of the sensor based on how small they look. Personally have not bothered to shoot flats when doing lunar or planetary and have just cleaned the sensor window if i see dust spots like this. If you keep getting dust on your sensor you could fit a nosepiece with a threaded in UV/IR or similar wide filter on it to act as another dust protection layer. You would still have to make sure everything between the sensor and the filter is dust free, but once it is you have less of a cleaning operation remaining.

Depends on how much below 0 we are talking how much trouble it will be. 0 to -10 not much will change, it will be a little bit cold and instead of dew you get frost. Frost is better though and easier to prevent than dew so this is a good thing. Dumb batteries are not worth it in these temperatures, but in my opinion they are not worth it at all, you need some kind of regulated smart power solution or just AC power to use the kit any length of time. Basically all equipment survives this and works as intended without much in the way of hiccups. -10 to -20 you start seeing the real problems. Mounts will become sticky and difficult/impossible to balance properly because of that but just knowing before hand where to place the dovetails and counterweights solves this easily. Focusers (even good ones) tend to be sticky too. Dumb batteries are useless and will drop below 12v in minutes, its a complete no-go. Coupled with that there is the issue that your mount draws more power because it is getting sticky so you could completely lose tracking/go-to with a simple battery that does not keep the voltage propped up to 13.6v. Below -20 the same problems continue but every degree more is a chance to develop an additional issue. Mount electronics become unresponsive, like the handcontroller that will take several seconds to change what the LCD display shows you when browsing the menus. The actions themselves do work but the display has a 5 second delay. Computers will likely also have an input delay of a few seconds but they will keep working in the background and complete exposures in a sequence happily. Tablets/smartphones will be slow too, keep them in your pocket/under your jacket to make sure they are operable. In short, british cold is not a real mechanical issue for astrophoto kit. Even decent cold of say -15 is still a minor issue if you prepare for it.

Its not very clear even if one knew where to look, but earlier than last july models of the camera had either an AR coated window at around 300-1000nm or a UV/IR window that cuts off at 650nm (before Ha! Which is why most people have the AR coated version). New options are an AR or a proper UV/IR window that passes Ha and sulfur and ends somewhere around 700nm i believe.

Actually i peeked into the .FITS header some more. You had an 82%!! illuminated moon at the time of shooting the sub. Cant expect anything out of a single sub like that and this one is definitely not the cameras fault.

At bortle 6 skies a single x5 read noise swamped exposure is not really useful as an analysis tool at all. You would need at least a hundred of these to start getting an idea on how the image turns out in the end, and why the 1600MM was better i couldnt tell you. You are comparing a mono camera to an OSC one however, so there is the obvious sensitivity difference there. Even with the higher QE of the IMX571 chip compared to the panasonic something something in the 1600MM the mono one probably still has the edge (if comparing to Lum).

I did some pixel math for your 2 frames here. I subtracted 500, which is the offset in your fits header, from both the light frame and the flat frame and voila, working flat frame. Of course its not perfect since they are not mechanically matched and there is only one flat frame but the conclusion here is that you 100% have some issues in your darks/darkflats/both. Synth calibrated frame without the bright corners (but doesn't work as a flat anyway):

Flat frame looks ok, would expect that to work. Light frame looks terrible, almost as if it was taken under a full Moon or under heavy light pollution. Very low SNR with barely any target visible, but looking at a light pollution map your location should be pretty good. Lightframe looks also exposed long enough with at least 25 electrons of median signal per pixel which is enough to swamp read noise x5 if you used HCG mode. But these 2 alone wont explain why the flats did not work, can you post the 2 most likely culprits - a dark and a darkflat. *Divided the lightframe with the flat frame and looks like these are not matching. From different nights, different orientations and looks like different OAG positions? Anyway, these wouldnt work even if the overcorrection were fixed.

The coatings on most (good quality) filters are incredibly hard and can take a beating so if you have to touch it to clean it you neednt worry much about scratching it. Obviously you have to get rid of any particulates of dust before that, rubbing it in is a great way to grind the coatings off. But for fingerprints, grubby hand marks and so on you can wipe it clean safely.

Inexpensive probably not, APS-C and even Micro 4/3 sensors are on the large side for astrophotography. Since the technical stuff is not important you may want to look at used mirrorless or used CCD cameras. Used CCD can be found for cheap since the market has mostly moved on from these. If platesolving the focal length is the target the sensor doesnt need to be as large as a crop frame one so you could find an old CCD for cheap enough to fit the purpose. Most dedicated astrocams are either 12.5 or 17.5mm backfocal distance so should work. Some mini cameras are like eyepieces and have whatever distance you need. Those ones have small sensors though, but for just focal length measurements should do ok.

The ZWO supreme council has already decided the discussion - feel free to ignore my contribution to it as its a popularity contest at the moment and all there is to say has already been said in this thread.

Looks like a decent product actually, ill have to eat my words from my previous comment where i just bashed the product based on the numbers alone. From Tokyo the image Cuiv got seems pretty good for the price and i cant think of anything that competes in the price category.

Love his sense of humor. This one clicked with me, something with the upbeat music and whats happening on screen makes it so funny:

I think its an agreeable statement to say that firecapture and sharpcap are both superior to the AAP in terms of lucky imaging of solar system objects? It may be a small difference for the typical imager but it is one. I agree that we have a golden situation with options at the moment (AAP one of them of course), but i wanted to point out that in terms of raw specs of what you COULD do the mini-pc option is a little bit better and potentially a lot cheaper.