Mandy D

What a wonderful night, for you! Then to cap it off, the aurora. Sometimes, I forget what I am mising by not doing so much visual. I also have a 300 mm Newt and the 50ED which I was using as a finder on it. I agree that it is a wonderful little scope and for relatively so little money. I've now repurposed it for deep-sky astrophotography with my my ASI 178MM.

The UK "smart" motorways programme has been put on hold due to increased incidences of accidents. I wonder how LA is doing it differently that they get a positive result whilst Britain is failing. Would you mind explaining to us Brits what exactly your computerised highways look like in technology terms. What is the purpose of the computerisation and how does it work from a user perspective?

So, by your percentage figure, only a single person in 10,000 billion has any interest in the exploration of other planets? So, basically, 1/1000 of a person! More than half the people I willingly associate with in real life have an interest in seeing the exploration of other planets and everyone in developed countries in the world along with most developing countries benefit indirectly from space exploration, whether that be LEO, planetary or other. I'm sorry, but there is no way I can agree with your statement on any level.

@Chrb1985 Think about it like this: Concave is like a "cave": goes inwards. Now look at a magnifying glass: this converges light and brings it to a focus and it's two surfaces are convex (opposite of concave). The job of a barlow lens is to diverge the light rays to create a larger image, therefore you need the opposite situation of a magnifying glass, hence both outer surfaces must be concave.

So? Split them into smaller sections and send the m one at a time.

Try https://wetransfer.com/ You can send files up to 2 GB. Just mesage the link to whoever you want to access the download. Just use your own email address as recipient when uploading the files to WeTransfer.

LEDs are monochromatic light sources. They do not produce broad band spectra, which is why we see the big spike at around 430 nm ( blue). To get white light from LEDs there are two common methods, one is tri-colour, with red, green and blue emitters which, when the light is mixed in the correct ratio, produces an approximation to white light. The second method, is the most common and certainly being used in street lights and most other "white" light sources. The blue photons carry high energy (remember E = hν, h is Planck's constant and ν is the frequency associated with the photon), which exceed the level needed to excite fluorescent materials which then release visible photons in a broader band which can be seen rising to the right of the main spike and then tails off at longer wavelengths. The fact that 430 nm LEDs are used, explains the high blue content in the spectrum of "white LEDs".

Walking home a few night ago from a friends house after we'd been drinking, so left the car behind, we noticed that the leaves on trees were acting as pinhole cameras and producing muliple images of the light array on the pavement, just like we get images of the Sun on the pavement in daytime. As a migraine sufferer, I find it very uncomfortable. Not enough research effort is being put into lighting systems and schemes and the same can be said of car lighting. Apparently, it is only epileptics who are considered in the government research with regard to lamp flicker. The pulse width modulation flashing on car tail ights is particularly irritating to migraine sufferers, but is OK according to the government because we don't count. Apologies if I have rambled off topic, here.

I can certainly notice a difference between my 200P and my 250PX. The latter gives me a noticeably brighter image and shorter exposure times on the Moon. I've never felt the desire to stop down with the 200P, but I recall being dazzled by the full Moon and deciding to use the 50 mm aperture in the cover to reduce brightness. In terms of handling these two scopes, I don't struggle measurably more with the 250PX and it takes up exactly the same floor space and height in my hallway as the 200P - the bases are both 520 mm in diameter. The 300PDS is another thing altogether and it is honestly a struggle to carry it, but that is as much down to diameter as it is weight, which is 26 kg. The other downside with it is tube flexure, something I have never noticed on the smaller ones, but this beast is almost floppy. I am going to add two more tube rings to it and some long Losmandy dovetails in an attempt to stiffen it up. I don't notice the benefit of the larger mirror as far as light gathering goes, as I mostly use these telescopes at native FL and the 250PX and the 300PDS are of similar focal ratio, due to the longer FL of the latter.

Hi and welcome to the forum.

@BrendanC Curved spider vanes might remove or lessen the diffraction effect.

@Breakintheclouds you can always build your own. I'm considering making one for my 300PDS, using a pair of tube rings and two Losmandy dovetails to carry the pivots on with a "lazy Susan" bearing for the Az. Have a look at the stunning Dobsonian mount that @PeterStudz has built. I'm sure he'd be happy to share some info.

@PeterStudz it's an interesting phenomonon. I've never seen it and it looks like I got up too late, anyway, but I did grab a couple of images that has the moons in a nice arrangement. https://stargazerslounge.com/topic/413587-jupiter-europa-io-callisto-ganymede/ It must have been realy cool to see.

I was imaging the Moon this morning, but decided to turn the scope onto Jupiter and grabbed a couple of images of the planet and four moons. There is no fifth moon, here, it's just a background star, although nicely aligned!

This morning provided good enough skies to get some pretty reasonable images of the Moon at 2400 mm FL with the 200P. The images were acquired around 05:00 against a bright sky.

The usual starting point for most astro gear offered for sale in here seems to be about 2/3 of the current retail price. If it does not sell at that, you can always reduce the price. Or, if you are looking for a quick sale, start slightly lower.

@astrolulu I have an i7 quad core laptop, but Windows has given up the ghost. Maybe the best way forward would be to put Windows 11 on it, or even Linux if we are only using it for image acquisition. I can always process on another PC.

@astrolulu I've had the ASi 178MM since the last Mercury transit, but not used it since. I do not currently have a laptop that is working, so I am going to have to buy some longer cables to view it's output from my living room. I have a tablet that, apparently, I can use for focusing, then I'll switch to the PC and do the image acquisition from my living room using ASI Studio or similar. So, until the cables arrive, I'm stuck with the DSLRs. Everything you say makes sense, but is not technically feasible just yet. My list of equipment appears in my signature.

@astrolulu Thank you. Yes, indeed, there is a mismatch for maximal results and I really need to get set up with the 178MM. I'm in the process of obtaining the bits I need in order to do this. Perhaps, I should have used the D3200 with it's slightly smaller pixels (compared to D800), but I had no idea the seeing was going to turn out as good as it did. If tonight is similar, I'll go with the D3200 - closer but not there. I guess I could have stacked my 2x Barlow with the focal extender and gone for 4.8 metres. I was just too concerned with grabbing images whilst the conditions persisted. That link looks very useful. Thanks again. I'm learning lots, here.

Nice result, again! Here is my effort from 04:30 this morning. I went outside at about 04:00 to check on the sky and Moon and, although the Moon was looking a little hazy, the stars were rock steady with not even a hint of twinkle, so bad back or not I had to grab the 200P and set up. The Moon was still quite low in the sky and I was shooting over rooftops, but nothing could be done about that. I pointed the scope and camera at the Moon and it was blurred and hazy. A quick twist of the focuser and it literally snapped into focus just like with an excellent refractor - such is the power of good collimation! I zoomed in on live view and there was no wobble or shimmer, whatsoever! I have never seen things so still, so I ran a few frames off and could see that the scope was still cooling. I then grabbed a load of images at native focal length before deciding I had to try the telecentric focal extender under these conditions. I still need a spacer for that! I grabbed a couple of hundred frames and shot a couple of videos of the Moon drifting through the frame. Looking at the videos when I got in, it was obvious how perfect the conditions had been, with no shimmering or wobble that I could discern. The attached photo is at 2.4 m FL with the D800 doing the imaging, best 25% stacked in AS3., then processed in GIMP. My result does not match yours, but I am slowly improving.

100% right, high altitude for this baby! Before we get to high quality imaging of the Moon with this, I need to stiffen the tube as it flexes far too much, so I reckon on adding another set of tube rings and fitting two long Losmandy dovetails 180° apart with shorter ones 90° round from them. Then, I just need to build a mount to carry it, as it will be well over 30 kg with everything on it. First impressions are that the mirror looks good and it is now close to collimation. The last part of the equation is getting my skills up to scratch!

@Mr Spock sorry to hear this. It is not nice to lose any sight for any reason. Mine was forcibly taken in my observing eye about a year ago and I had to swap. It took months to get used to it and I am still not happy with the switch, but no longer try the wrong eye, so it is possible to adapt and get used to it. I am now waiting on the surgeon to decide when I can have the next stage of treatment, which may restore some more vision. I hope you don't have to give up on something you love. Good luck at the doctor's.

The Moon has been horribly low, especially when near full. Now that it is climbing again, I'm going to up my game. I've just started planning my deepsky rig, but intend to keep going at the Moon as it is my favorite target. I now have a 300PDS and will eventually drop the ASI178MM in it and point it at the Moon. I'm learning a lot about collimation and, like you, finding out how much improvement it makes for so little effort.

@GreatAttractor Nice work, wonderful images.

So, I connect the camera to the tablet with an OTG cable? This sounds like it might be a solution.