pipnina

I do have a mischievous cat however even his powers of destruction haven't affected my telescope yet. No kids to speak of. I have only assumed so far that the mount or EKOS simply loses track of where the mount should be pointed... But why now after years of it working fine? Perhaps i need to look into mechanical issues as a struggling stepper motor or slippery clutch could maybe cause it to wig out? I don't know enough about the finder details of the skywatcher mounts under-the-hood operation, do the handsets act as the whole brain while the board inside the mount simply works as a stepper motor controller? If so It could be EKOS making alignment issues. If the brains are inside the mount then maybe I could plug my handset in and give it a factory wipe of some sort? I always power up my setup pointed at the pole star with the counterweight pointing as close to straight down as possible. Usually the first goto slew will be off by some ten thousand arcseconds or so but the first platesolve will bring it within a few hundred, and by 4-5 platesolves it's normally in the 20 second tolerance I have set in EKOS. I feel like I should have a security cam pointed at it (for multiple reasons) as I think many issues with controlling it from indoors would be solved if I could see it while controlling it!

Imaging was going well on M101 a few nights ago, but when it crossed the meridian EKOS/Indi or the mount itself had a wobbly performing the flip and it kept pointing in the wrong direction. I went outside a few times to right it back to home position after hitting park in EKOS. It messed up each time. Eventually i hit park for the final time and gave up. When I looked at it the next day I saw it like THIS! I had to perform a lot of careful maneuvers to get it out of there between the tripod legs! I have no idea how it managed it or how mount positioning could go so wrong... Could this be something to do with EKOS's alignment settings? I cleared them a few times when it was parked and also let it "sync" in the park position so it knew it was pointed at 88 degrees on DEC etc. It still refused to point properly.

First of all, my condolences! Rest assured you aren't the only one who did something stupid today... I will be making an "oops" post myself tomorrow. It's possible you could buy a replacement optic from TS themselves, as they have a selection of telescope-building supplies including lenses: https://www.teleskop-express.de/en/telescope-accessories-5/telescope-diy-improvement-299/telescope-making-optical-parts-91 Maybe there's even a triplet that fits your telescope OTA? Who knows.

For a small sensor I'd agree with the samyang. No direct experience but people's results with it that I've seen have been terrific. I own a 135mm f3.5 canon FD lens for my AE1-Program. Even wide open it has incredible full frame coverage but just a bit of blue fringing that could probably be taken out with a UV-IR cut filter:

Might explain why my hammerite application went so badly... It was 5c at the time!

I've used hammerite at work, sadly they bought it in paint pots and we were painting onto paint (valve handles needed to show what the valve carried by colour) Brushing it on wasn't most effective... They looked a bit like a red tar monster when we were done haha. Bare mild steel will corrode very rapidly in wet environments. Rust is also supposedly self-perpetuating and a small amount of rust formation will crack or bubble paint allowing more oxygen access to the metal. I suggest completing rust removal, preferably by wire wheel (you can buy them for home electric drill chucks, flapper wheel may also work). If you want to ensure it's moisture free in the cracks or pits you could always stick the metal in an oven at a skin safe temperature for a few minutes. I need to think about all this myself, as my HEQ5 is starting to look a bit shabby with some parts of it rusting up and the counterweights losing their paintwork... Eventually it just catches rust and there's nothing you can do about it I guess. I suspect modern cars can avoid rusting on bodywork much more easily since they can control the conditions and state of the bare metal much more easily in the factory before applying multiple layers of rust protection below the paint.

Same here. I look in mine and see rust and during operation it sometimes stops and needs to be off-on cycled so I fear repair could be in its future... Or the crashes are purely software based...

The film cost was that high!?!? Was Kodak tech pan that dear or are we talking about some sort of scientific glass plate that's hypered, high speed but fine grain, and comes in sizes of 4x5 inches at the smallest and requires cooling and gases to store? A normal colour roll of 35mm or 120 was quite affordable until only very recently when the costs rocketed up.

The sky at my home has an Exposure Value (EV) of about -5.5 or so, and it's already dark enough that the ground is very hard to see even once I'm adjusted. However a place near me is much darker, dark enough to see the MW core and even sometimes the outer spirals, which means it's probably closer to EV-7 or even EV-8, I can see the ground at this level but not clearly. I would guess if it were just the MW core in the sky and no sky glow at all, I'd struggle to see any ground at all as you say. The milky way just isn't that bright!

It may be different up north where you are, but in devon I can manage about 1.5-2 hours of imaging during the astro dark holiday if weather permits, and with narrowband imaging I can get away with a bit more. The brightest sky I see from that period here is when the moon is out, which means a moonless night in that time window is still better than normal full moon conditions, under which I'd either image a target at opposite sides of the sky to the moon, or use narrowband, and my results are usually somewhat decent as the last few years the summer period has had a good number of clear nights so I can make one target a multi-night project (relative to UK average...)

Wait noise adds with the square root?? How does this work?

I want to improve the speed of my setup. I worked out that if shooting only RGB then the ASI 2400MC would afford me effectively the same resolution image as my RisingCam 571 (6000x4000) but with a wider FOV due to the larger pixels, since I am speeding up my imaging with a normal camera lens I expect that would be best for star shapes anyway, while affording me a 1 stop boost to my speed (so 6.2x faster than my RisingCam+ f5 scope) However it means narrowband (My main interest turned out to be Halpha only really, not worried about the loss of SII and OIII) becomes much less efficient as only one subpixel gathers data for it. If I got the ASI 6200MM I can keep my narrowband capacity but with the 3.76 micron pixel size, the same as my RisingCam, I won't gain the speed increase as I would with the 2400MC. Unless, I binned. A 3200x4800 image might be a little small for me but could be servicable. However this increases the effective read noise by a factor of four even though in theory is gives me a 2 stop light sampling boost right? So am I worse off with the 6200MM and should stick to RGB imaging with the 2400MC if I want speed, and simply forgoe narrowband for now? Interested to hear thoughts. Thanks

I only have a cursory knowledge of electrics in motors in general, but I think as a motor spins faster the magnetic back force increases which means you need yet higher voltage to move the motor. I'd guess if voltage correlates to max speed it's because of that. Holding torque I'd guess would be current based as the strength of the magnetic field is proportional to current and not voltage.

The number of bars on the rotor shows you the step angle. A 1.8 degree motor will have 100 bars on the stator and 98(IIRC) on the rotor. A 0.9 deg motor will have twice as many. Yours certainly looks like an 1.8 to me

I bought one of these and it seems to be quite good Of course it will be most effective once the sun goes down. You can position it some distance away while your camera is on a tripod, focus on it and the picture will show you the sharpness you can expect from stars. Just adjust the camera's orientation to position the fake star at different parts of the frame: https://www.firstlightoptics.com/other-collimation-tools/hubble-optics-5-star-artificial-star.html For smaller camera lenses (nifty fifties?) I'd guess the larger holes will be suitable and nice and bright once more than 10m away. For bigger lenses ideally you want as much distance as possible. Most lenses will decrease in quality as you focus closer.

This lens does have a built in motor, and given it was designed in 1987 that's definitely way ahead of its time as Nikon would use the in-camera motor until I think the 2000s. I suspect the need for the motor to be insanely fast to track sports and wildlife led to this design choice. The lens from reviews I've seen almost literally snaps into position on subjects, and this lens is big, so moving it (and quickly too) would put a lot of strain on a wimpy in-camera motor I think. Regardless, all manufacturers use in-lens motors now and only pro tier nikon DSLRs have the built in motor for legacy lens support (Nikon D850, D7500 and similar). The bit that irks me is not being able to manually focus the lens AT ALL without it being powered. But then the lens wasn't designed for people who would care about that I assume...

Ah yes you're right there is only the original lens (the one I got, from 1987 https://global.canon/en/c-museum/product/ef270.html) Which is not IS but does have the ultrasonic motor. Then the subsequent 2 versions are simply IS USM and IS USM II. I just re-checked the ebay listing and they don't mention broken motors. I suspect I got it uncontested because of the very minor damage to the front element (two small chips, noticable but I suspect not ruinous to the image, won't know for sure until I can test it though!) I still have my fingers crossed (now that I've been re-injected with hope due to this adapter) that it'll prove a very suitable replacement for my telescope.

Sergey from Astromechanics replied to me earlier, managed to work out a way for me to pay and that the UK does not impose the same restrictions as the EU so they can deliver it to me directly. They suggested 12-20 days on average until it should arrive, I await it patiently and thank you guys for letting me know of its existence! Feels a bit wrong to buy from russia at this time but alas it seems they are the only ones who have made the exact part I need.

My goodness! If I can get my hands on one of those it'd be just the ticket! It would solve the challenge of autofocusing as well which requires some jury rigging on manual focus lenses. I've sent them an email as their website seems to suggest the UK doesn't impose the same level of sanctions as the EU... I await their response. I'll hold onto the lens for a bit to see if I can get hold of the adapter. If I can it might just push me over the edge to buying an asi full frame camera haha. It's been my plan to downsize from my big scope to something faster and more portable so if this lens and adapter work... I'll be over the moon! Thanks for the links both of you!

I thought I scored a real deal when I won the bid for a Canon 300mm f2.8 L (non is non usm) for only £600. Given the lens was originally over 4000 I felt pretty good about it. Until I got my hands on it today. And learned that it WILL NOT manually focus and cannot be focused AT ALL unless a canon DSLR is attached to it. So it may as well be a brick as far as my astrocam is concerned! I am beyond disappointed and to make matters worse, my normal DSLR is a Nikon so I can't even use it on that. I guess I can only hope that I can return the lens to the ebay seller and find another set of optics to try for compact and fast astro imaging unless anyone knows a way to hack it lol

Captured back in January on my 130mm f5 triplet. Forgot to post here at the time but quite pleased with the result- just wish I got another night or two to add data to it.

I have tried to do astro with my Pixel 6 in a similar way with the same app. I also ran into the same flat calibration issue. I suspect the lens suffers too greatly from internal reflections. I also noted that despite the images supposedly being RAW, it appeared as though the camera was still imparting a white balance into the image which may affect matters. I also struggled a LOT with hot pixels. Did you succeed at removing or handling them in your phone? In my case I was shooting in summer so it was 15c outside. I also did not have BlurX or NoiseX. Certainly however many differences in technique (or hardware from P6 to P7) your result is miles ahead of what I achieved!

I think Alan has created a more pleasing level of contrast and balance of colour than the photo editors of the hubble project. However one cannot deny how impossibly detailed and sharp the hubble image is (and always will be) in comparison to our meak sub-meter telescopes! Hubble images often have an almost greeny tint to them and sometimes squander the red colours. Alan has captured a beautiful blue hue in the galaxy with maybe a slight magenta lean and has produced incredibly vibrantly scarlet hydrogen. That's my take at least.

I think if this image were any better it might make Hubble blush!

Just got my first roll of Kodak Ektar developed in 35mm format. I took some astro shots and while i can't get them quite right I feel they're still worth sharing! First is this star trail shot from a local beach. 24mm lens so pretty wide angle. I can't get the shadows to stop looking red though. I don't have a proper negative scanning software so I am just trying to fix it manually. All I did here was colour balance and some contrast enhance. Was about a 40-50m exposure. This was a tracked shot of orion with my 50mm lens. My scanning job again seems less than perfect with it being a bit out of focus. Nonetheless barnard's loop, M42, flame, horsehead, rosette, and SH2-264. I dare say either my brain is wishfully thinking or the witch head is in there too! I provide it here both with only contrast and colour balance improvements and with a pixinsight gradient removal, to show how the film natively recorded the scene as well as what I was able to extract from it easily. Even the new pix gradient tool didn't tackle this image perfectly, I am not experienced enough with it yet to get perfect results. Finally I have one with the very nice 135mm f3.5 canon FD lens. Aside from a bit of blue fringing this lens handles astro very nicely. Nice detail starting to show up in M42 and the horse's head itself becomes visible as well as some veins in the flame. I couldn't get the image to look neutral in pix so I had to settle for it either looking blue or orange... Not sure why! I intend to try shots like this again but with my medium format kit. Ektar proves to be a very capable film stock for astro and the raw sensitivity to h-alpha puts any unmodified DSLR or mirrorless to shame. My RisingCam 571 is still the much more sensible choice of course. But I am having a lot of fun with film anyway!