Mnemovore

Archive for July 2008

A small linux astronomy software review

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UPDATE: Another updated post with some new apps is available here.

Using linux as a main operating system can still be tricky sometimes, especially when you want to combine your job with your hobbies. There are many astronomy programs for unix/linux. A good example is that most of Nasa’s servers run Solaris, so unix had always the upper hand in the exploration of universe and of course in variable astrophysics calculations. Recently i ve read that nasa, runs solely Fedora Core for timing servers and for some other jobs, Mandriva. By reading interviews and such is easy to understand that nasa’s engineers and programmers dont have any os wars to worry about. If it works we stick to it. No updates, only stability. I strongly agree with that philosophy. Im using Slackware for nearly 9 years and i havent changed os because it simply does what im asking to do.

Most of the programs below are open source. I have also included some DOS programs that can be used via dosbox simulation.

Xephem is an ephemeris and planetarium, astronomy software which is a bit difficult to use at the beginning but it becomes a necessity afterwards. Many features icluding a really huge catalogue of stars, deep sky objects and data from AAVSO, SOHO. You can use (after conversion) the tycho2 and hipparchos catalogues, connect it to Guide Star Catalog (with 998,402,801 objects) or view a sky view using Digitized Sky Survey. Eehh not enough words….

Predict rocks my socks.. Its a satellite tracking and orbital prediction program. Very useful for any kind of satellite tracking you wanna do. Just grab a small scope and on to the roof.

SkyChart / Cartes du Ciel. No introductions needed. An astronomy software that is used by many, even though its still in beta (for linux) its very usable and with the addition of extra images and catalogues it can be your celestial encyclopedia.

Stellarium. A very good planetarium program that is used by many amateur astronomers and even in commercial planetarium projectors for educational porpuses. Many claim that its strictly newbie application, but i really believe that thats rubbish. With a default catalogue of over 600.000 stars, scripting, realistic atmosphere, additional catalogues of over 200.000.000 stars, nebulae,etc i dont think that its newbie..

Partiview is not exactly an astronomy only related project. Its an interactive, stereoscopic and 3d viewer. Its pretty fast and has a ton of uses. One of the most famous is Digital Universe. Take some time and check the “Uses of Partiview” section in the main site, believe me, you will be surprised by the uses in astrophysics, global networks or even machine learning.

Just Moon An experimental but highly usable lunar atlas similar to Virtual moon atlas. Very nice and simple program. I hope for some updates in the future.
(Note: if you still want to use Virtual Moon atlas go for the light version (3.5c) with wine)

PP3. Latex finds astronomy. One of the best celestial charts generator with very high graphical quality and uses latex. According to the author, PP3 is used for the maps of all constellations on Wikipedia. A small example is here. Even though the syntax that you may use to generate charts is not latex code its very simple and really fast to learn.

Siril is an image processing linux software (IRIS clone) that is used
by many astrophotographers. Even though you can still use gimp for that, Siril just makes life easier by using the features that we need most.

Skycalc is a small console calculator made for many quantities that observational astronomers need. Its very practical and light.

Newt is a newtonian telescope design program. Many atms(if not all) use it for their projects for its rich features and high data accuracy. You can use it to check for vignetting, optimizations of the diagonal size, calculations of the baffle size and a lot more. I use it with wine and never had a single glitch. 2 thumps up!

If you dont use a computer a lot with your observations be sure to have a calculator with you all the time. Saved me countless times.

If you require more, you may check my links, but i think that most of the above fulfill most of your base needs.
Of course if you cant find nothing that matches your criteria, you may write something on your own and share it with others ๐Ÿ™‚ . A good example is scripting in any language or engine such as GnuOctave, Scilab and Matlab.

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Written by aperturefever

July 20, 2008 at 12:49 pm

DIY 30 cents Binocular tripod adapter – Collimation Mini Guide

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Yesterday i found an old pair of binoculars in the closet. The manufacturer is Soligor, based in Germany. After a small inspection the specs are 10×50 and wide angle field of 7ยฐ. Pretty sweet for a pair of binoculars that came from nowhere!

The bad news were that it was badly collimated and that resulted in double images. First steps were buying a photography tripod. I just got the taller and cheaper heavy duty stand i could find. It costs about 40 euro from Media Markt, end height is at 1,85 meters and its really sturdy. Next stop was outside a paint shop where i asked for a shelf holder and a 5mm screw (Full cost 30 cents). Simple as possible and the only prequisite was having enough durability to hold the bino’s weight, so it’ll keep the bumps unnoticeable. The holder can stand about 60 pounds (30 kgs) of cargo. It had the same price with the others and its just a bit more bulky. Next stop home. I connected one edge in the photo tripod (it has an embedded screw for cameras) and the other with the screw in the adapter hole of the binos. Simple enough eh? Just for the sake of cost efficiency i visited an online astronomy supplies store to check that the binocular holder is about at 20 USD…!!

Next step is collimation. Collimation in binoculars is an easy process but requires many trial and error steps. Firstly try to keep the binoculars stable and at a comfortable height so that you can see through them easily. One of the best advices i have ever heard about binoculars is that when looking through them, you must be calm. No tension in the neck, shoulders or face. It will just ruin your focusing. Close your right eye and adjust focus using the main switch. After that close your left eye and open the right correcting the focus via the right ocular switch. Yes, double images or in general foggy images will still be there. Under the plastic cover as shown in the picture below are 2 screws, one for each ocular. As you suspect these are used for lenses collimation. You can try adjusting them by looking through the binos at the same time, but you might end up with a pretty scratched surface. The best way is to adjust and check, adjust, check etc. You can try collimating your binoculars by looking at a faraway mark but i would suggest doing so by looking at something bright.. Its summer.. Jupiter is a nice target. Some patience and voila! This pair of old binoculars still has life! I ever consider taking them with me on holidays.

Finally a small tip.. When you want to clean the lens never breath/spit/hrrrr/hhuuhhuuu on them. Never. It will ruin the coatings and decrease image quality… A piece of cloth used for cleaning glasses is the safest way..

Written by aperturefever

July 15, 2008 at 12:33 pm

10″ Travel Truss Dobsonian “Lysithea” – Part 1

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A couple of months ago, after a chat with a ATM wizard named Stathis Kafalis i decided that it was a good time to start constructing my own telescopes. Building something with your own hands of course gives you a great learning curve, saves your pocket and exercises the brain. Also is the best way to start observing Deep Sky .. Having all these in mind I started drawing, throwing away papers and checking on line resources. Some books that helped a lot were Richard Berry’s “Build your own Telescope” and David Kriege’s, Richard Berry’s “The Dobsonian Telescope – A Practical Manual for Building Large Aperture Telescopes”.

Well, a 10 inch Dob is not what we call a “Large aperture telescope” but its pretty decent for DSO and is in a safe range to pack it for travel. Travel means pack it up in your backpack and start walking in the desert. No cars and such… No airport problems.. and of course as little hassle as possible (characteristic that derives from minimalism)

Everything has to be very lightweight, sturdy, compact and surely not at the expense of performance. A combination of wood and aluminum in addition with a couple of commercial parts will keep the whole build light.
In this part i will describe the commercial parts i have used ( Note: I have no commercial relationship with any of the vendors or manufacturers mentioned in this article. I just use their products ๐Ÿ™‚ ) The choice of the focuser was pretty easy, and with the addition of the kind comments from cloudynights.com i ended up choosing a 2″ helical type. Why? Its small, light, VERY practical. To be honest i had never used a helical focuser before but since the design would be minimal i had no problem trying new ideas. I fetched the helical from kineoptics.com (Thanks Joe and Della). The package had the HC2 focuser with A kit ( for added stiffness with large eyepieces) and replacements for any kind of screw that the whole system has. The whole idea is very good and with small adjustments you can achieve perfect focusing.

As for the finder I got a Telrad. Its pretty light but needs batteries.. Im thinking of making a DIY Telrad using the system that hand powered flashlight use. Maybe in the future. For now its just perfect though. Its very easy to locate objects and far more easier for star hopping. If you have the batteries its the best solution, but i ll have a simple optical finder with me just in case.. These are the commercial supplies i used.

I also got some extra tools. These iclude an electric jigsaw (Bosch), screws of variable sizes that will be described in the post regarding the main construction, plywood blades (2mm-15mm) for the jigsaw, Jigsaw compass (20cm radius), 2 constrictors to keep the pieces firm and lots of sandpaper. In addition i got four, 40cmx40cm “Multiplex” plywood pieces with 6mm width and two, 40×40 pieces with 9mm width for the rocker box. The trusses and secondary cage materials and photos of the procedures will be described in later postings too. Well, the cost would be higly reduced if i already had the tools but now i have the tools to build as many telescopes i want ! ๐Ÿ˜€

Written by aperturefever

July 14, 2008 at 12:57 pm

Which is the best telescope ? …Dobsonians ? Maybe? …

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A question asked by amateur astronomers all the time, beginners and experienced. Well the best answer finally is the scope that you use all the time. The same goes for bicycles. The same goes for everything. As a species we are nomadic, expansionist and of course garbage collectors. We enjoy having something for every situation. But back to the subject..

There are 2 types of scopes. Reflectors and refractors. Reflectors use mirrors, refractors use lens. Also there are 2 types of mountings. Equatorial and Altazimuth. There are some reflector types..Newtonians, Cassegrains (Maksutov-Cassegrain, Ritchey-Chrรฉtien(Hubble telescope) and Dall-Kirkham).

One type of reflector that uses the altazimuth mounting and the Newtonian type tube is the Dobsonian telescope. Taken its name by John Dobson, a former monk of the Ramakrishna Order and amateur astronomer, this scope is built with simplicity in mind, is constructed by cheap materials and is mainly used for deep sky and planetary observing. Unfortunately we live in a world that money leads the way. But the sky is ours and the dobsonian is a very good way to observe it. Most dobsonians are atm (amateur telescope making) projects and have 3 main parts. The tube, mirror box and rocker box (mount). All parts can be easily made using a hammer and a saw. As for the mirror you can grind one by yourself or buy a readily made one. Of course there are commercially made Dobsonians like the Meade Lightbridge and others..

Yesterday in science.nasa.gov there was an article regarding mirror making using moon dust. Its not hard to think that future generations in moon with no special components will start building dobsonians for their observations..

Of course nothing is perfect and there are some tradebacks. For starters its pretty difficult to motorize this kind of mounting if you want to use it for astrophotography. But there are commercial(expensive) products to make your life easier. Or you can make a DIY project ๐Ÿ˜‰ Also there are issues regarding heavy finderscopes or uncommon eyepieces that will alter balance. There’s a solution to that too by adding counterweight to the rocker box.

This video by truemartian makes a small comparison:

Well.. its not hard to decide which is the most practical enjoyable and easy to transport.

This is considered to be the largest made dobsonian.. A magnification of 1600x has been achieved.. and you can actually make it!!!

Note: There are many good telescopes of any kind type or mounting. The above are just my views of a scope that has some more pros than cons.

Written by aperturefever

July 10, 2008 at 4:09 pm