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My Desktop Telescope calculator


AlexB67

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Hello,

some people like to play with telescopes and equipment while the clouds pass over. This little pet project has kept me busy in the last few weeks on and off, the idea to write myself a basic telescope calculator started a few weeks ago to learn about various things, the main aim to have some fun first and foremost, and so it is has been. :)

The tool is mainly aimed at beginners, to see what does what with a specified telescope/eyepiece combination when certain parameters are varied, but it may even help the slightly more experienced to consider what to buy next, crunching some numbers to help in the decision process.

TCalc is currently mainly configured for Newtonians and DObs,, that being said, a lot of the formulae used are universal anyway for a lot of the features. TCalc has been inspired by various online calculators that do similar things already floating around the web, the aim with this one to pull it together in one neat little app. When done It should run on most types of devices, apple, Linux, windows, iPads as it is written in C++/Qt.

I attach some screenshots showing it in operation on both windows and Linux on the KDE desktop, at least this is how it looks currently in development, that is not to say certain extra features will not be added. In particular a graphical view to see how an object fits in the field for view for various objects would be a nice feature to add ( I have it in mind as the next development phase ), or the icing on the cake, to animate the entire transit across the field of view in real-time in the long run.

I wondered if it would attract any interest in the community at all, seeing I went this far with it, so thought to throw out my efforts so far to the lounge with this post. If there is sufficient interest I would hope to release it to the public at some stage, and in the mean time keep you posted every once in while of new developments, when there are interesting new features to show.

If there is no interest no big deal :) it has proved a handy little tool on my desktop already that has made me appreciate and learn some things about telescopes and eyepieces since I started.

That said and done. I wonder if I can ask some assistance. I've already found two sites that got extensive collections of data on eyepieces and telescopes, and I would be very grateful if they would be willing to export such data for me to use In my application, in particular field stop data seems scarce. If they catch this post, they are probably members here feel free to message me, of course I appreciate and understand if they are not willing to share it. I can mail them in any case and try to strike up a conversation and see where it goes :)

Either way, all the data can be entered in custom mode in the tool, but to have the list of extensive pre-sets would be nice bonus, especially for beginners.

Many thanks in advance.

btw I don't know if this is the best place to post this, but it is software after all, not sure how often this part of the forum is read however. Admins feel free to move it if you think of a better place.

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Having a lot of fun with is, the ocular viewer has been added, well it is in development is a better way to put it. I Hope to have a good list of them in there to select from, if not the complete list of Messier objects if I can help it when done.

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Yes, very interesting and nice presentation :) I'll be watching this with interest. Could I suggest you might add an imaging view later? (if you can find a database of cameras). As an imager this would be extremely interesting as I have yet to find the perfect (or anywhere near) software for this. Most are limited in their list of deep sky objects. Of course, I realise that this is a very difficult job and I salute you in tackling it :):icon_salut:

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Excellent work my only comment would be if it's aimed at beginners then showing them glorious colour views of Galaxies etc may lead to disappointment when all they actually see feint grey smudges...

Peter...

It is on the list of TODOs , it is part of what I am trying to do and working on at the moment. What is displayed in the development screenshot is the raw unprocessed imaged as it is, but I am working on adding grayscale factors and blurring techniques, the final image will be post processed down ( inside the software ) before it is displayed on the screen. So I am keen to make it a bit more realistic in looks, though it will always be an approximation.

Scanned sketches would also be an option, though they would have to be good quality and in realistic proportions, otherwise that will raise some other issues, anyway, I have not ruled that out as an additional option.

In any case. I'll write a help/support document with it, pointing out what the tool does, what to expect from it. Already each input and output field has build in help information in the form of tooltips.

@Gina. I'll bear those options in mind, but that would definitely be further down the line, notwithstanding there is a bit of a learning curve as I know 0 about imaging in astronomy. I'll keep an open mind as to what could be added in the future in terms of features, who knows, the sky is the limit :)

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After a bit more coding what is still rather crude blurring and grey scaling, my first stab at what m13 could look like in a smaller scope under not so good skies, how I remember it anyway roughly. The back of my mind says the inverse of a wavelet transform may be able to do something in this also. Something to read up on I guess. Lots to do. This is the calculator loading in the image in my previous screenshot and what it currently spews out. Certainly not so Hubble like anymore, at least a bit more what I am aiming towards :)

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  • 2 weeks later...

Latest progress.

Development has been taking place, added a few features and also a logging utility to warn user against bad eyepiece telescope combinations as well as other problems that may arise such as bad exit pupil sizes, it is being refined all the time with more stuff being added :)

The main focus has been on the FOV calculation and improving this part. I have come to my senses whilst doing some research, and along the way realised the errors of my ways to some degree. That is what 10 - 15 years of IT does to you of hammering in crude solutions and putting plasters on things :D, but this should be free time to do what I want, and that means getting back to getting a bit more scientific, getting the research hat back on, and carefully consider what is worth doing/including and what is not :) Simple blurring is certainly not the answer, thought it may be useful along the way with other image processing techniques under certain conditions for some objects. That being said I do believe I can improve on what is currently available on the web as shown on a site like this for example http://www.skyatnigh...view-calculator

I don't know when all is said and done how it will compare to any commercial offerings that do a similar thing, but in the end of the day this will be free software.

See some screens attached where I am going with the calculator, and the FOV viewer showing what M81 could look like more realistically compared to other FOV calculators out there. ( Ignore the surrounding the stars that are too dark, which I hope to isolate using some other techniques, such image cluster analysis at some point, and also ignore the FOV figure quoted in the viewer, it is not actually representative of the data used right now .).

Hope to have a first release ready in the coming weeks depending on whatever else is going on :)

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  • 1 month later...

Thought it was time to update with latest progress. Things are still happening and working on it ( on and off while the clouds are over or not doing something else ). Added some new features

  • eyepiece editor, add you own eyepiece data
  • telescope editor, add your own telescope data
  • Report generator giving detailed results and other interesting parameters and .. stuff about the scope, i.e additional stuff besides what is put on the main window.
  • Interactive graphs, zoom in and out, very any parameter such as focal length, aperture, and get instant realtime feedback via plots using various controllers to changing a parameter, we all like a bit of instant gratification with mimimum effort :)

It took some time to write the graphing functionality, as I did not want to depend on any other third party libraries outside of Qt, so I wrote my own to make things hard for rmyself . I would like to offer something a bit diffent to what is already out there on the web and the various other offerings that already exist. It will hopefully will turn out to be a quite handy educational tool for beginners, and perhaps even for some of the more experienced observers that want to learn what happens in a telescope when you change a parameter. With the plotting utility you get instant feedback via the plots to see that graphically, as shown in the example plots, change anything, aperture or something else, and the graph immeditely updates to display that and you see the effect of that change. Screens are all on the linux version but the windows version is working too. Sorry, screens got rather badly degraded in the conversion to jpeg and size reduction uploading, but just about enough to see it I think.

I can see light at the end of the tunnel for a first release some time, but it is more fun working on it, adding to it and thinking about a release when it is the right time, whenever that will be, it is a hobby after all :)

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  • 2 weeks later...

Thanks, no not as yet. It is very much alpha or pre alpha I would say right now :), but I'll be uploading something in time no doubt, there is light at the end of the tunnel for something useful I hope in the near future. My own problem is the more I learn, the more I want to add/change improve and it becomes a vicious circle, though that is the nice thing about a hobby, no deadlines, though I will draw a line under it at some stage for a first release when I have the enough of the features working in the way I like it to be.

Working on the ocular viewer again now, and adding features to that, like zooming in an out at the touch of a button, change other parameters such as aperture focal length on the fly and see the changes instantly in the viewer, instead of the approach of select eyepiece, select scope and a fixed magnification output ( as it was till now ).

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Had some time today to work on it further and work on the ocular viewer before I go away on my holiday.

I added optional support for sketches too. I had some interesting result with Qualia's artworks but will not show them here before asking permission to use whatever sources I can use. Anyhoo, new features include.

  • Ability to adjust parameters such as aperture, focal length etc and see the results instantly in the viewer ( zoom :)).
  • Each image gets pushed through some image processing and some crude rules applied, this is still very much being worked on, but to give a rough idea what it could look like in a scope. When you select a scope and eyepiece, or customise any of the parameters like focal length or aperture, the calculations update the resulting image in the viewer.

Right now not as yet very scientific more than a computer based sketching technique fi you'd like to call it that, this is something I'd like to tie in more with limiting magnitudes in future, but for non-stellar targets, not so easy and learning to be done. I doubt I'll be putting that in the first release, but in a future release and improve it in time.

Screens show the windows version this time and show what happens in two different scopes, my own beloved heritage, and at a similar mag in a bigger scope. Image compression seem to ruin it to some degree in the uploaded images, but looks better on a real PC screen, but hopefully just enough to get a rough idea.

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  • 2 weeks later...
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Time for another update.  I've not been working on it lately that much with other things interfering,  but slowly getting back into it and building momentum.  I added support for other telescopes. To begin with the calculator was mainly setup for reflectors, but now refractors are in there too with SCTs coming, as all these scope types need slightly different treatments for some part of the calculations.  

For the ocular (FOV ) viewer  I added a night mode and full screen ability, so when sitting in a dark room with the FOV viewer maximised full screen it can be better appreciated what is seen. 

Tying in with magnitudes for extended objects is still on the list, though some things are already simulated, but for this I am awaiting some books on inter library loan to decide how much of that I will build in for a first release. The ultimate aim to drive towards something Qualia wrote in his great post on what can be seen in a telescope,

http://stargazerslounge.com/topic/196278-what-can-i-expect-to-see/

but to make a visual interactive version with this app. 

Sketches and images are both supported. Certainly the FOV viewer is a WIP but you get an idea with more buttons and what not to add to that do additional things.  Screens show the ocular viewer both in standard mode as a window, or in night mode. In both cases images are used that are pretty much Hubble quality, but by the time the app has eaten them up it looks a lot more representative taking into account the scope used. 

Also added some other features not mentioned here like an interactive calculation mode for the main calculator window so results are shown instantly .. to become clear at some stage   :)

As always portability is checked across Linux and windows, rest assured both versions are working.

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