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Posted by Naimul Islam Opu at 18:43 on 2011 Jul 12
Hello, for astrophotography i need a tracking device, (equatorial auto tracking) please suggest me any specific model which one is reasonable price… or if any BAA member have any extra one / unused then can i borrow it? or i can buy in a secondhand price… please let me know. –Opu from Bangladesh
Posted by Paul A Brierley at 19:49 on 2011 Jul 12
Do you want to use this with you’re 8" CPC? Or are you after an alternative?Firstly, if you wanted to use it with you’re current set up. Then you can buy an Equatorial wedge. This will then convert you’re existing Alt/Az mounted SCT, into an equatorial, and it will then be suitable for photography.But if you wanted to just use a DSLR then the Astrotrac is easier.http://www.astrotrac.com/Default.aspx?p=how-it-worksThis is an updated version of the tried and tested, barn-door mount and is very simple to set up and use.If have not done any astro-imaging before. Then I would recommend buying one of these first and see how you get on. Have a look at there gallery page and you can see for your self, just how versatile the Astrotrac is.
Posted by Naimul Islam Opu at 04:24 on 2011 Jul 13
Many thanks Paul… no i am not using it with my 8" CPC just planning for wide angel DSLR astrophoto… I saw the link of ‘astrotrac.com’ its quite impressive! 🙂
Posted by Andrea Tasselli at 08:31 on 2011 Jul 13
What telescope or lens are you planning to use? And what imager? BestAndrea T.
Posted by Naimul Islam Opu at 06:36 on 2011 Jul 14
Hello Andrea, my planning to take some wide angel sky photograph, spacially Bangladesh Night sky with long exp.@24mm. so I bought a DSLR sony alpha 200 with some prime lense, I want to shoot from the Himaliyan ground sky (N) to Bay of Bengal (S)… its a very amazing sky beauty, thanks – Opu
Posted by Andrea Tasselli at 09:50 on 2011 Jul 14
Hi Opu,You don’t need any equatorial platform to get deep sky images with a 28mm lens, just a decent tripod (or you can use the one of your SCT adding a bracket for cameras to the tube) and a remote to operate the camera. You can shoot for up to 15s around the celestial equator (and longer toward the poles). You then stack the set of images using the procedure and software described here:http://astrosurf.com/buil/iris/new430/new430_us.htm (scroll toward the bottom)Alternatively, you could use the LX90 in a fashion if you can lower one leg enough for the tube to point to the North Pole and adjust the position in azimuth of the mount. This is a kind of makeshift equatorial that could potential provide up to 1 minute exposure time (that depends on how accurate your tube axis is pointing to the pole). This should be feasible at your latitudes since the tube inclination is moderate.Andrea T.
Posted by Andrea Tasselli at 11:52 on 2011 Jul 14
Sorry, diregard my last suggestion. Obviously you can’t do that. I must had the brain in black-out.Andrea T.
Posted by Naimul Islam Opu at 15:25 on 2011 Jul 14
Andrea… many thanks for the suggestion! I like the software, the link is very useful for me… indeed! ahh the problem with LX90 is the weight I cant move with thats kind of tracking device from up Himaliyan regeion to Bay of Bengal 🙂 I’m trying to find out something easy to carry with backpack, I think a decent tripod will not surve my pourpose coz i want to visualize the backgroud of the sky, Milky Way, other deep sky objects as much i can able to show in to the frame… also i will use 16mm lens, 24mm lens, 28 etc… clear skies! Opu
Posted by Callum Potter at 16:18 on 2011 Jul 14
Hi Opu,you could make yourself a ‘barn door’ or ‘scotch mount’ – it is a very simple device for tracking at the siderial rate, and quite portable. There are many internet sites that explain how to make one, and there is also an article in the latest Sky and Telescope (August 2011) with a very minimal design (but a bit US centric).Also in the August 2011 S&T is announced the Vixen Polarie tracking mount, which looks somewhat more compact than the astrotrac, but is not yet available to buy.Finally there is also the Orion Min-EQ Tabletop Equatorial Telescope Mount for which a drive is an optional extra. I am not sure how good the tracking is (not the best I am sure), but might be adequate for short exposures (up to a minute maybe).Or there is always the option of a small equatorial mount head, like one of the EQ range, or a vixen polaris.I hope this helps.Regards, Callum
Posted by Graham Relf at 16:36 on 2011 Jul 14
On my own site I show how to take non-trailing photos with a simple camera on a fixed tripod, stacking with my own software which you can download. The page is here. On subsequent pages I show how you can go on from there to DSLR, equatorial mount, and so on.Sometimes I don’t have my equatorial mount available, only DSLR and fixed tripod. So here’s an example of a photo I took of Comet Hartley and the Perseus double cluster last year, on fixed tripod: here.I do recommend you experiment with the simplest equipment first. You will be amazed what today’s cameras enable you to do (with a bit of software).
Posted by Naimul Islam Opu at 06:14 on 2011 Jul 15
Thanks Graham, I downloaded you software its working very good! & the article you wrote: ‘Photography – creative & technical’ its increase my mind, I’ll do some experiments & share with you… include GRIP 🙂
Posted by Naimul Islam Opu at 06:39 on 2011 Jul 15
Dear Callum, i’ve tried with ‘barn door’ ‘scotch mount’ or say ‘screw mount’ technique, made it myself some projects but its seems to me sometimes get very good result but not always after several uses occur some errors… i’ve lost many film exposure… first time i was doing astrophotography with film DSLR & ‘screw mount’ is only my tools to do long exposure 🙂 I will try to collect s&t issue as you mentionedMany many thanks for writings Clear Skies! Opu
Posted by Roy Hughes at 16:55 on 2011 Jul 15
Back in the 1960s we all made clockwork equatorial camera mountings out of the elderly (even then) clockwork time switches available on the surplus market.Googling around I found an old page of Maurice Gavin’s version at:home.freeuk.com/m.gavin/tracker.htmI don’t know where you would get the clockwork time switch these days but it might give you some scope for lateral thinking.Roy
Posted by Naimul Islam Opu at 19:41 on 2011 Jul 17
Dear Roy, very interesting suggestion, I am searching for a clockwork motor, already visit several old mechanic shop in my town Dhaka… lets see but i think its not so easy to findout something like that now but I found a Photocopy Machine DC motor with a gear box (made by strong plastic), it is available in nowadays electrics market… just I need to control the motor so i am planning to make a voltage controller circuit to control the motor rpm… its seems to me easy to build an alternative cheep tracking system for anarchic astrophotographer :), i’ll let you know the update, if it is worke then I’ll write an article how to build in our BAA I&I section… thaks for the clockwork idea it helps me to findout the solution. Best wishesOpu
Posted by Roy Hughes at 14:34 on 2011 Jul 18
I got curious that Maurice Gavin’s seems to be the only design of clockwork drive available on the net and decided to dig around in old copies of the BAA journal (both digitised and paper!).In 1974, vol 84, no 3 (April) page 189 D. G. Daniels describes a similar device looking a bit more like the one I built (long since gone to the scrapbox in the sky). If you’ve got a fast connection you can download a copy from the BAA (6.57Mb) a real blast from the past. If you do then rather than spend hours trying to scroll to the right issue do a search for time-switch (the "-" IS important!).Roy
Posted by Nick Atkinson at 14:57 on 2011 Jul 20
Michael Covington had a circuit in his book on Astro Photography. I did construct this buying the chip from Dontronics in Australia for Circa £4. This produced a square wave form that was capable of driving a £240 volt syncronous motor. For the dec control you need a reversible DC motor. I modified the circuit with a half bridge driver and constructed a push button controller. You do need to have some experiance in soldering circuits.
Posted by Roy Hughes at 09:31 on 2011 Jul 21
I re-wrote Michael Covington’s software and built a sucesful drive for my old orange tube celestron. Works very well. I’m still using it.My old, now orphan, web page at http://mizat.club24.co.uk/ has details and links to Micheal’s site.I suspect that this will be overkill for this application. It pulls nearly 1 amp at 12 volts. Unless driven from a car’s battery the total result including a battery pack would be far from portable. I took a similar arrangement cobbled together from bits of my home telescopes to an eclipse in Africa in the 70’s and given that it only had to work for a few minutes a 12v stack of D cells worked OK. They didn’t XRay luggage at the airport in those days otherwise I would probably still be in jail today as the resutant stack looked just like the bundle of dynamite sticks that often featured in the cowboy films of my childhood!Roy
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