pipnina

There's Trouble with Triplets? Might explain my frustration then as I'm using a triplet apo (SET Optics 130 f6, can't find much about it, got it 2nd hand) It has a rather large number of little screws around the lens cell, but I haven't touched them as I assume they adjust the three lenses individually. I have touched the screws around the edge that seem like they're for tilting the whole lens cell in one go however. Maybe I'll have a look and see if I can get someone to look at it 😕

Just come in after about 2 hours of staring at slightly defocused stars and twiddling with the front lens cell. I have either made things a lot worse, or have managed to change nothing! I tried only adjusting one of the 3 collimation points (loosen main screw, tighten grub screws) which was the one roughly in the direction of the offset bright dot in the middle of a defocused capella. I could see in my 10mm EP (80x on a 130mm scope), a large outer ring, some blurriness in the middle (a bit of atmospheric turbulence tonight) and a bright spot to the right of center. But no matter how much I adjusted the front lens cell, the bright spot would not move. Do I need to put the lens cell in a certain orientation for it to be adjustable? Like loosen all the grubscrews and just do up all the main screws just barely, then start loosening them off to adjust tilt? I also noticed that when I turned to jupiter, the dot appeared on the left side instead? And I could only see through a small part of the EP, but maybe that was a reflection... I dunno. It seemed very odd. It seemed like getting closer I never got to see the whole 50 degrees of afov, only a small off-center circle of it, but then, jupiter was in the field and very bright around that area too... Are there any tips for doing this by eye? I seem to be making a mess of it : ( Considering sending it away for someone professional to work on it haha. Do @FLO offer that service maybe?

And from what I hear about radio hams, they'll probably manage to collude to work out where the noise is coming from and come have a chat if it bothers them lol. I've heard they are a very knowledgeable set of people, as to be allowed to use the equipment at all you have to go through a lot of training and courses. One lived opposite me for a while and had a big antenna going from house, to garage, to fence to house, and apparently talked to people around the world using it. Didn't speak to him much however.

The big problem with adapters like these is they consume a lot of backfocus. This one starts at 20+mm, which is as thick as my filter wheel! They could be suitable for some of the fancy refractor, or typical cassegraine correctors, but where most correctors ask for a 55mm~ spacing, you'd likely have to give up an important bit of kit to accomodate one of those. I think that adaptor also would rotate the camera as you perform an adjustment? I can't quite tell. It's an option I've considered but they don't seem like they'd be helpful for anyone using a 55mm spaced corrector, unless they only need the camera and an OAG perhaps. It also moves the camera so definitely affects focal position, I don't know how much moving the corrector only affects the focal plane position but it could cause less motion and allow easier "real time" view of the corner star shapes changing.

Having seen many posts about the troubles of achieving proper backfocus spacing, and having my own issues with the topic myself, I have begun wondering if equipment manufacturers, as well as ourselves, are thinking about the business of corrector spacing all backwards. It seems pretty expected that we buy a corrector, and then add things between it and the camera, be they female-male spacers, shims, off axis guiders, tilt adapters etc etc. But because of how accurate we need to be for most correctors to the ideal spacing, we end up outside in the cold constantly unscrewing our cameras or opening our filter wheels to add and remove and change our camera train to get that spacing just right, needing an autofocus routine every time we make any changes. It's slow, tedious, and exposes our kit to the elements and increases the risk of dropping things. My filters were nearly pristine when I first sealed them in the filter wheel, but I have had to spend so much time fiddling with backfocus this year they are starting to get a bit coated with the sticky kind of dust that doesn't just blow off! I am not keen to try and clean them but the dirt I see in my subs does annoy me. And so I wonder, why don't we move the corrector instead? If correctors were fitted with a kind of helical focuser, that could move the lenses inside up/down the barrel, we could add our bits together in the camera train to achieve a rough spacing from the corrector lenses to the camera, but when it comes to fine-tuning it in the field, we'd just need to undo the locking knob on the corrector and shift the corrector lenses up-down a bit until we get to perfect spacing that way. No finnicky disassembly, no dirty filters or camera sensor windows, no ice cold fingers trying to handle and tell apart 0.5mm shims from 0.8mm shins. Just turn the helical focuser of the corrector by 1/8th a turn and take another photo... How has this not been done yet?! Do we suffer all of this because of the upfront cost of building the correctors into their own mini-focuser, only to spend that cost on shims and spacing rings (and our sanity) instead?

I tested most of the kit last night: So far everything is still working. Pleasantly surprised! Laptop, cam, Guide cam, Filter wheel, focuser etc all seem to be working. Only haven't tested the mount yet, as it is in the shed. Hopefully when I run some power down there that turns up all clear as well. Feeling somewhat relieved.

Some laptops support creating their own WiFi acces point. A Google might help you work out if you can do this and get the NUC to connect to the laptop that way. After that, VNC is a good suggestion as mentioned above.

My dad has a few bags of that stuff for the car. Seems to work ok but sadly I don't have an airing cupboard or similar to put things, and the house tends to be rather damp as previous owners made very dodgy building choices. My room is a garage for example, and the back room is a patio that they put two extra walls and a ceiling on top of... Not exactly "to code". I'm going my best to dry everything out at the moment. Telescope itself seems fine, no sign of water between the triplet lenses and it all looks very clean. Just a matter of if the ZWO EAF+EFW + 120MM mini, and the laptop and camera are ok... Fingers crossed... Thanks to those who recommended removing the laptop battery, thankfully it was easy on mine (only 2 screws and it pops out by hand). And the laptop is now sat half open near a radiator for its second night.

I think it depends on the program used to view the image. Editing programs seem to prefer NN interpolation, like RawTherapee (image 1) and PixInsight (image 2). viewing programs like windows media player and chromium browser prefer bicubic or similar smooth interpolation algorithms.

So I went to bed at about 3am last night, and woke up to my dad coming into my room at about 11am saying it was raining. The telescope, laptop, etc were all dripping wet. I've taken everything besides my mount indoors, and the mount back into the shed. I've tried drying everything off as best I can but I don't want to risk testing it yet and give it more time to dry out, as I don't want to risk it being OK but getting damaged by power-on and shorting. I could have sworn the forecast last night said rain wouldn't start until some time in the mid afternoon, and with less than 40% probability. I suppose it served me right for not wanting to go back outside and spend 20 more minutes in -2 weather when I just wanted to go to sleep. Been saying for ages that I should buy a weather cover, should have done it I guess 😕

I just took a picture with a bahtinov mask on. Looks normal in the middle, but in the top right and bottom left corners, the diffraction spikes seem to CURVE!? In the top left and bottom right however, the diffraction spikes seem compressed on one side and stretched on the other? Is this indicative of a specific problem? I've also noticed that the focuser is shifting again, when pointing east... I need to look at my cables and grub screw tightness again I suppose...

The 5mm spacer arrived! I have it out now. But despite best efforts things still aren't right! I added two 1mm shims and there still seems to be astigmatism... and something else in the bottom left?double cluster test.fits I include the fits since the jpeg edit I made might not be the best for seeing the problem...

If your stacking program has an averaging mode called "sigma clipping" or similar, try that with a sigma of 2 or less, I found it very good at removing these hot pixel trails. Good luck!

Indeed I bought it from a fellow SGL user recently! I think you may have dodged a bullet however, I had to get a machinist involved to get the 3" focuser installed. The 2" crayford that came with it was absolutely not fit for purpose. It was wonky (more than 2mm deflection, produced poorly collimated stars and tilt as a result) and the grub screws that held it onto the circular dovetail flange were not sufficient either, and they also showed signs of a previous owner having frustrations, as the flat head cut in them were burred over and stretched as I tried to tighten them. I ended up spending about £500 on top of the cost of the scope, to get a working focuser, plus weeks of stress worrying that I was out £2k before I worked things out with a machinist at work. I may as well have bought an equivalent scope new...

I looked that model up just now, the only sad thing about most astro cams at affordable price ranges (i.e. below 1k) is the micro-sized sensors 😕 Someone used to an APS-C camera switching to that Atik 460 will have images with only 1/4 the "surface area". So in some ways it seems a bit wasteful, as 75% of the light being collected by the telescope isn't being recorded vs the APS-C DSLR. I can't argue about the quality of images it would produce though in comparison... But the loss of so much light and FOV is bound to make those gains a painful compromise.

Hi! It's a "SET Optics 130mm f6.6 APO" According to the previous owner the company went bust, I am the third owner of this scope so I am a bit distant from the original product page. I havent found anything about it online besides mentions of it being the same triplet lens cell as used in the now discontinued TS Photoline 130 f6.6. That said, without the corrector (unflattened/unreduced) platesolving claimed the scope only had about 800mm of focal length, which is closer to f6.1-6.2 than f6.6... I've done a check on the focuser, by adjusting the tilt plate again. This time I used the laser and the crosshairs-paper on the front of the telescope, but instead of just aiming for the center of the paper, I noticed the laser got a reflection back from the lens cell. No chance to test this but I did adjust the focuser tilt a little to get that back reflection from just off center to bang on. I also tried to tighten the grubscrews on it a little. The weird thing between the image where the focuser looks fine, and the second one where tilt is evident, is it was on the same night's imaging! I think a meridian flip had occurred... I realised why I was adding so many spacers trying to achieve backfocus too the other day when I was at work, it was because my previous newtonian scope also had a 55mm backfocus corrector, but had an m48 connection camera side. I hence used a 6.5mm thick M48-M42 step-down adapter, which is now missing as the corrector for this scope is already M42 like the rest of my camera end equipment. I found an M42 extension ring of 5mm on ebay, due to arrive in a week or so. Hopefully that lets me solve the issue as I have run out of threads to add spacer rings too for now! I hope to test it again when the bits arrive, thanks for your response!

I think a prime example of this effect is seen with the HST and JWST. They might take a half hour integration and have a nice clean result, while being f22! Meanwhile my f5 130mm telescope on the ground would take several hours to approach that level of SNR. Difference being that those scopes have 85mm square (not diagonal) sensors onboard, whereas I only have a 24mm width sensor. Maybe at that size aperture has something to do with it, and for sure they have the whole being in space advantage which probably works in their favour rather strongly, but I was shocked to discover that both of those space telescopes were above f20, which is often considered unusably slow for many normal photographers as that aperture reduction tends to soften the image and usually lets in too little light.

This is quite unfortunate to hear. I have two WEGA printed mounts for my ZWO EAF (for the TS 2" crayford, and the TS3" R&P) both of which cost more than 40 quid each! I have to say I had an easier time with them than you, though far from perfect In my case, the crayford bracket was a rather clever design using a friction fit, as the focuser has a gentle taper on it, so the circular smoothed-out plastic could grip the focuser quite snugly and the connection to the focusing shaft kept it in place. Even then however, I found I had to file the inside gently to get it to go over the focuser at all! Which wasn't great, and there was a useless little wing that was meant to go under the focus motor area, held on by a tiny little M2 or M3 sized screw, which promptly stripped the threads in the PLA material with barely any effort. Thankfully that wasn't a functional piece! The one for the TS3" R&P was better, although it was a single piece and didn't rely on friction anywhere. I feel like us amateur astronomers have more use cause than most people to own our own 3D printing equipment, a lot of us would probably save money on the 200 quid investment after a few months or years!

Just looking at youtube shorts and this pops up, I am not sure exactly what he was seeing but I have a hard time believing it's anything but a satellite of some sort. What do you think?

Wait, so should I have been flipping my newtonian's images horizontally? (assuming camera's sensor's wide length points to the front and back of the tube, if that makes sense?) I never considered that I was looking at everything backwards in only one direction!

Looks like a nice little instrument! As for the wega stuff, indeed it is metal-machined prices for 3D print quality- but I suppose 3D printing has allowed the product to simply exist on the market at all, which can only be a good thing. I'm getting my own 3D printer (in the post atm) so hopefully when I next get the need for something printed, I can just smash something out in a CAD program and make it myself. When I first got a wega adapter for my EAF and TS crayford, I over-did the little M3 bolt that held a little clip on and sheered the thread clean off. Thankfully it wasn't important but it let me know just how flimsy this PLA stuff is! Out of interest, would it be possible to remove the plate joining the guidescope's rings together, and then use the bolts holding the guidescope assembly to the lens rings, to hold the guide scope AND lens in one go? Might improve rigidity, make it a bit lighter/compact, and look a little tidier? I'm looking forward to the results!

I have a 130mm f6.6 triplet and so far have struggled with the current Photoline ED 0.79x corrector i'm using, as regardless of the spacing I use some astigmatism and curvature seems to remain. I have seen the riccardi m63 0.75x as one option as a flattener-reducer upgrade, but the explore scientific looks like it could be a good alternative at a similar price. The ES can screw directly into my TS 3" R&P focuser I think, as it has an m68 "zeiss" (?) thread. It also has a slightly stronger reduction which could be good for my setup as my guiding isn't great, the backfocus is also a bit longer than the riccardi, so I might be able to fit in an OAG and a backfocus-adjuster. Meanwhile, the riccardi looks good because it still has more backfocus than my current flattener, and also shows me the spot diagram and vignette I can expect (very tight stars even on full frame, and no vignette until the very corner of a full frame sensor, and even then it's only supposed to be 3%). If the ES is better, it sure doesn't, advertise it... Does anyone know which one might be better? At the moment I am leaning toward the riccardi. Cheers!

Having been able to test my 3" focuser upgrade, and using my laser to adjust the focuser tilt to be as square as possible (as best as I can get it! maybe in a tolerance of 1-2mm at the objective lens), I have found I still have some issues with the images produced by my frac. I think some of it might be sensor tilt, or possibly collimation (I had to cut the tube and re-install the flange, so some movement could be expected). I think in the images shown the spikes coming from the stars might be the heat packs I stuffed next to the lens cell to stop it dewing up (heater straps still WIP) but I can't tell until I next take the scope out 😕 I did notice that when adding and removing shims from my backfocus total, the astigmatism level didn't seem to change much. I'm finding the point at which it goes over from saggital to tangental tobe very hard to pin down. I am wondering if this corrector maybe isn't able to correct an APS-C sensor, as the previous owner used I believe a 1" format. I can't see any obvious coma in the center, so maybe the issues I have left are purely to do with the corrector and a little bit of sensor tilt? I did try and check the camera for tilt when I got it and couldn't SEE any movement of the central laser dot, but that doesn't mean it isn't there... On the other hand, maybe the tilt could come from the various threads joining the camera to the focuser, such as the thread from corrector to filter wheel, to tilt plate, to male-to-male, to camera?w I did notice that between the two images above, I had a meridian flip, and after the flip it seemed to make things worse, what do you think? Here's some whole images to go with it: Processes I should run through prior to and during the next session with the scope are greatly appreciated! I was hoping the world of fracs would be a bit easier to navigate but alas I am still struggling haha. EDIT: The flattener is a TS-Optics 2” Photoline ED 0.79x specifically.

Adaptive optics mirrors can intentionally create astigmatism, coma etc. So I imagine they could adapt to the prescription of an observer, or that filter thread lenses could be used as a more practical solution. But I think normal eyeglasses won't work due to, as you say, the shape of the light being an exit pupil instead of a cone. I think it would need some alternative shape to traditional prescription lenses.

I imagine any adaptive optics system that works for imaging will work for visual observing too. However the cost of such systems is still very high, far out of the reach of us mortals. I think I have seen telescopes with adaptive secondaries before, but they were "ask for quote" price!