Annehouw

Here's an oldy from my side (and Bortle 5 site). Originally from an OSC camera, but converted to grayscale and inverted to see the very faint stuff a bit clearer. Quite real if you ask me, but also very faint indeed.

For rentals look here: http://www.athos.org/ I have been there a number of times. Wind can be strong on top of the Roque de los Muchachos, so bring warm clothes. You might try the parking lot of the visitor centre to find some shelter from the wind.

My mount is controlled by an ageing FS2 and I have been thinking of the "what if it dies" question for a few years. It turns out that I am not the only one. I found a group that is developing a successor to the FS2, based on the OnStep project designs. You can find a discussion (in German) here: https://forum.astronomie.de/threads/teenastro-ein-onstep-projekt.259256/ More information in the user group, which has a Wiki: https://groups.io/g/TeenAstro/wiki/Home The only catch is (and that is the reason I have not migrated yet) that it is a build project: All the electronics and software development has been done by the team, but you have to 1) have the PCB printed (using the design drawing that is provided) 2) order the electronics (there is a parts list) and 3) assemble the hardware. According to the discussion group, total cost will be around €200,- but of course you will have to put in the effort to do the soldering.

Yes, indeed. The more I read about it, the more I get the feeling that this could work for LRGB. The electrochromic materials are available as coatings, so a thin layer on flat glass would give the optical quality probably: https://www.european-coatings.com/articles/archiv/electrochromic-polymers-create-coatings-that-change-colour Now, a lot of things need to come together. Bandpasses that are fit for our purposes so that a complete visual spectrum is rendered. Very low or non existent hysteresis so that the fidelity does not diminish. Enough color density by the thin coating. Narrowband is another interesting challenge. But how nice it would be to tune the filter to a specific wavelength electronically (instead of tilting as currently in test at the dragonfly array). I have my doubts whether the amount of research needed is warrented by this part of the amateur astro market, but who knows.

Search for "astrobiscuit the big amateur telescope". You are not alone.

Here, there and everywhere, there are long threads on mono vs OSC. Ignoring the intricacies (and (non-)validity) of the arguments pro or contra, there is a lot to be said for mono in astrophotography. The practical side is that some (a lot?) of us are using a camera that is placed in the light beam. RASA, hyperstar and in my case hypergraph. Putting an unwieldy filter wheel in the lightbeam is a big no-no. Changing filters in a filterslider manually can be done (and that is how I started) , but is rather tedious. Thinking of solutions, I have thought of various mechanical alternatives for a filterwheel, but none of these solutions are real, practical, repeatable or stable. So a mechanical solution seems to be a dead end. So what if it could be done non-mechanicaly....and indeed, this could be done in theory. There is a class of "electrochromic" materials that can change color under the influence of an applied voltage. I found a recent mention of "smart glass" that can change color (and very rapidly as well). The researchers also claim that they can isolate small parts of the visible spectrum. If this would be narrowband enough is not clear from the description. These kinds of materials are commercially being used, but mostly as a means to darken glass (e.g. in glass windows). This is just a bit of fun in thinking of "our" problem and I have no idea on the practicality or affordability for our hobby, so it goes here into the science forum. Here is the link New electrochromic material can rapidly change color through electricity and there is a more elaborate pdf if you click through to te website of the Journal of the American Chemical Society.

@ollypenrice and others. You are quite right about the nature of the question, but color or mono was only part of it. As y'all know, a problem is easier to solve if there are clear boundary conditions. In this case there are a few and there are a few missing. Missing is the location of the op. Bortle 9? Then mono with narrowband would be something to prefer. Fast system? Slow system? That influences the cost of the filters required. And that brings me to what is in my opinion an important element: budget. GBP 1500,- is a sizable amount of money but in this hobby, it is spent before you know it. In view of a blanket statement from my side that with the current crop of sensors it is hard to go wrong, OSC of mono, what can you buy for GBP 1500? OSC: A good camera would be an ASI 533MC (or qhy equivalent). That is GBP 900,- GBP 600 to spare for a 1.25" filter drawer and, a UV/IR blocking filter and a good duo narrow band filter. Maybe even some money to invest in software and / or training. Downside is that the sensor is a bit smallish. Total investment expenditure would be a bit below GBP 1300. Kudos from the Chancellor of the Exchequer. For a bit more stretch in budget, the ASI 071 MC gives an APS-C size sensor and is GBP 1400,- IDAS NBZ (48mm) is GBP 250,- and then a GBP 110 simple filter drawer with extra holder and again a UV/IR blocking filter (GBP 50). Totalling GBP 1800 Mono: All APS-C / LRGB/NB filter options are way out of budget. The upcoming 533mono cameras would be a good quality choice. No prices yet, but let's assume GBP 1000,- ZWO mini electronic filter wheel GBP 180. ZWO LRGB filterset (1.25"): GBP 125 Optolong 6.5nm OIII filter (1.25"): GBP 115 Optolong 7nm Ha filter (1.25"): GBP 130. Optional a SII filter, but because I did not put it in the OSC calculation, I'll leave it out here. So, in total GBP 1550. Not too bad. That is if you can live with the smallish sensor. Some can, some can't. Note that I have budgetted relatively affordable filters. Especially on the NB side , one can spend a lot more (chroma, anyone?). Any of the equipment choices above can give the OP excellent results. Anne

Let me throw in a bit of a grumpy statement. You can argue forever about the pros and cons of gear. However, what matters most is mastery of the equipment. Any equipment that you have. And dedicate the hours in actually capturing light and getting results. Better to start with "simple" equipment that you like to use and that gives you gratification than struggle with equipment that is too far into the learning curve (cameras and scopes). Perfect is the enemy of good. Also in this hobby. Too much energy (and frankly said emotion) is dedicated to gearangst. Just go out. Do it. Learn and grow. CS. Anne

Reading this: "I’m prepared to spend up to £1500(ish) and ideally would like something that I can do planetary, solar and dso", my vote would be (like already noted) on a modern OSC camera with a duo narrowband filter. That is a versatile setup. I am very happy with my IDAS NBZ (at f/3). I am fairly convinced that for the ultimate quality mono with high quality filters is king, but that takes a lot more money. Personally, I cannot use a filter wheel in my setup, making mono imaging a cumbersome process. I started with mono but switched to OSC because of the hassle. Results are fine.

@vlaiv "Extraordinary resolution by the way - and better than anything possible with long exposure and amateur equipment, but again - not near to what 12" scope can resolve without influence of atmosphere." Agreed. There is room for growth in this technique. And that is the point I am trying to make. That with the current and upcoming sensors with small pixels, high sensitivity and low read noise there is a new frontier in high resolution imaging beyond the air turbulence barrier. How much beyond that barrier? I do not know but, like in the old days, not being afraid to fall off the flat earth opens whole new worlds. 😉 And for those still with us in this thread, a nice write up on the post processing side of this technique: Traitement des images en mode courtes poses It is in french, but with a lot of pictures and "astro-franglais" words. P.S: As to your questions on image scale/mosaic-non mosaic..I do not know. There is a bit more of behind the scenes here: http://astrophoto17.eklablog.com/recent/5 but not enough to answer your questions. CS Anne

Hi @vlaiv "Care to share some of your high resolution work?" I am afraid that will have to wait for a while. I am still in the early experimentation stage with no results to share for now. As an alternative, I can direct you to a person who I see as the current Grand Master in this genre: Stephane Gonzales aka exaxe on astrobin: Exaxe: NGC 7027 There is a lot to his skills. From this image you can see in the description section that he used an imaging scale of 0.17 arcsecond per pixel; the original reason I joined this conversation. Also note that his shortest exposures are 0.15s. So in terms of freezing of turbulence still room for growth. Even so, his results are spectacular (in my eyes at least). He has been perfecting his techniques for years and this image, as you can see from the description section, is quite elaborate in the way it was captured. My takeaway from this is that DSO Lucky Imaging has a lot of yet to be explored potential for amateurs as well. P.S. Stephane has a dedicated website with a bit more on his techniques: Astrophotographie avec la technique du lucky imaging Enjoy! Sorry to the @iapa for going off-topic on this thread C.S. Anne

Lucky DSO imaging has a lot of challenges. That's why it is fun 🙂 Let me address a few of the ones you mentioned. In popular parlance, lucky imaging is sometimes used for exposure times below 5s or so. That does little to battle the turbulence, but it does do a bit in the way of lucky guiding. Fot beating the turbulence, we need to be somewhere between 0.1s and 0.01s. I'll link some interesting papers below. - Alignment is not a problem in my experience. As with planetary images (where there is not a single star in sight to align on), modern software for this purpose does a fine job in quality selecting and stacking. I used SIRIL in my own experiments and that works well. - What is a problem with increasingly shorter exposures is read noise. For normal DSO imaging read noise in modern camera's is now so low that it has not a lot of influence. But when stacking thousands of very short exposures, this becomes an issue. This in practice limits the shortest usable exposure time. There are very expensive sensors like emCCD with very low read noise, but these are prohibitively expensive. Having said that, technology marches on and we will see lower read noise camera's for mere mortals in the future. One more thing: Inherently in Lucky Imaging, you throw away data. And, depending on one's criterion for sharpness, this can be a lot. So this is not a technique for faint fuzzies. Now some links for some interesting read work: Thesis: Lucky Imaging - beyond binary stars This is from 2013 and a bit dated by now, but it is a nice read. Lucky Imaging: High Angular Resolution Imaging in the Visible from the Ground This one is more recent. and a lot shorter than the thesis above. They report their findings at 12Hz

Haha, you got me there. 🙂 Said otherwise: with lucky imaging you sample for the resolving power of the telescope instead of sampling for local seeing.

A lot of sensible things have already been said. Resolution wise getting the resolution per pixel as afforded by your local seeing. Within that resolution, aperture gets you more light, so always good. A lot of galaxies are easy to image with not too much exposure time to get a pretty picture. It needs a lot more exposure time to image things like stellar streams from galaxies. A bit off topic, but one area where long focal lengths / oversampling can be rewarding is in the realm of lucky imaging. This is an intriguing line of imaging with a lot to be discovered. As exposure times are really short (equal or less than 0.1 second or so), one needs a lot of light gathering capability and / or very bright objects to make this work. There are very impressive examples (e.g. exaxe on astrobin).

Hi Richard, What a nice field of view! It is very nice to see some wider compositions of relatively well-known objects. Great image! CS, Anne