Petergoodhew Posted July 12, 2016 Share Posted July 12, 2016 What do people do about taking flats when using remotely-operated gear? Sky flats,? or a $450 flip-flat?! Link to comment Share on other sites More sharing options...
ChrisLX200 Posted July 12, 2016 Share Posted July 12, 2016 Have a panel on the Obs wall, point the scope at that (use the co-ordinates to 'goto' it). You can set the Home position to be pointing at the panel, but you do need a remote relay to switch the panel on. ChrisH Link to comment Share on other sites More sharing options...
steppenwolf Posted July 12, 2016 Share Posted July 12, 2016 I have a fully automated observatory that I often just use remotely and I have built my own automated 'flat-flap'. This works very well indeed and cost around £50.00 UK Pounds to make using a servo and a Pulse Width Modulation generator designed for use with electric train set layouts! It also acts as my telescope's dust cap. Link to comment Share on other sites More sharing options...
sloz1664 Posted July 12, 2016 Share Posted July 12, 2016 Hi Steve, I've followed your fully automated observatory thread with great interest and, in particular, your DIY automated 'flat-flap'. Any pointers on the build Steve Link to comment Share on other sites More sharing options...
steppenwolf Posted July 12, 2016 Share Posted July 12, 2016 Hi Steve, I'd be happy to give you any information you need. Inside the box that you see in the YouTube video, there are the following components:- 1. Single channel servo controller with adjustable start and end stops - this controller is normally used in electric train layouts to control a servo to open a locomotive workshop door, change points or action a mechanical signal 2. A digital servo 3. Power supply for the electroluminescent panel 4. A 12v DPDT relay that trips the servo controller and turns on the 12v DC power supply for the electroluminescent panel Items 1 and 2 are available from here - see the first three items under 'Servo Motor' Item 3 is available with the EL panel from here The plastic box, relay, flyback diode, Veroboard, power plugs and sockets came from Maplin. The 90 degree bellcrank and other servo mechanical connections to operate the flap came from a local model shop. I use a homebuilt 8 port USB switch using Velleman control/relay cards for several functions within the observatory and I use one of the ports to trip the flap. 1 Link to comment Share on other sites More sharing options...
Petergoodhew Posted July 12, 2016 Author Share Posted July 12, 2016 Thanks Steve. I will have a go at making one too based on your suggestions. Link to comment Share on other sites More sharing options...
msh1 Posted July 12, 2016 Share Posted July 12, 2016 steve any chance of a schematic or a pic of inside of the flip flat box please im setting up my obsy to be automated dont want to spend a fortune on a commercial one thanks mark Link to comment Share on other sites More sharing options...
sloz1664 Posted July 13, 2016 Share Posted July 13, 2016 Brilliant. Thanks Steve. Link to comment Share on other sites More sharing options...
ollypenrice Posted July 13, 2016 Share Posted July 13, 2016 The folks using the remote Observatoire Per Frejvall at my place have sky flats handled automatically via ACP. It points the scope at the appropriate part of the sky, dithers and sets the exposure, as I understand it. Nobody has reported any issues to me. I think the only painful part is paying for ACP! Olly Link to comment Share on other sites More sharing options...
steppenwolf Posted July 13, 2016 Share Posted July 13, 2016 Quote It points the scope at the appropriate part of the sky, dithers and sets the exposure, as I understand it. Nobody has reported any issues to me. This is a method that can be used too but it doesn't solve the dust cap issue which is why I decided against having a larger EL panel to aim at on the observatory wall, whereas my flat-flap serves both functions. It is, however, an added complication but once built and installed it can just be forgotten apart from an occasional wipe down with a wet cloth! What do you do about dust control at Observatoire Per Frejvall, Olly? Link to comment Share on other sites More sharing options...
steppenwolf Posted July 13, 2016 Share Posted July 13, 2016 Quote steve any chance of a schematic or a pic of inside of the flip flat box please im setting up my obsy to be automated dont want to spend a fortune on a commercial one thanks I'll sort something out for you. Link to comment Share on other sites More sharing options...
graemlourens Posted July 13, 2016 Share Posted July 13, 2016 Hi. I was also facing this challenge when completing my obsy. My solution surprised myself that it worked, but probably only worked by a good amount of luck. I had mounted a strip of led going a good length inside the dome based obsy. Just for fun i then tested shooting against a wall-part that had a even illumination and no structure to it. To my surprise i got perfect flats, and as the led's are not terribly bright, exposure times even for LRGB filters are not too short. I have been using these since. But i also have to say: If you're obsy is not totally remote (like 10'000km away) and you do not have a rotator on your camera, i don't see a problem to travel to the obsy once in a while to re-take a master flat set? Its takes my around 1-2 hours, and flats for 7 filters are automatically taken with SGP. I only re-take flats every half a year or so. As i do not rotate the camera, and small changes in focus in my refractor do not require retaking flats, i do not take flats after every session. But as i said, it really depends on your setup. I doubt my approach would work for OSC... Just my few cents Kind regards, Graem Link to comment Share on other sites More sharing options...
steppenwolf Posted July 13, 2016 Share Posted July 13, 2016 That's a fortuitous solution, Graem. As promised, a circuit diagram and some photographs of my solution. Please note that this servo is close to the limit of its operational envelope so an A5 panel is probably the maximum it can cope with. This would be usable on a telescope with an aperture up to about 130mm:- Circuit Diagram of Control Relay Internal Layout Servo Linkage Front Control Panel 1 Link to comment Share on other sites More sharing options...
sloz1664 Posted July 13, 2016 Share Posted July 13, 2016 Steve that's something of an engineering feat, in it's simplicity. Well designed and if I may say "finely assembled." I have to ask this question? Did you have a Mechano set when you were younger. Steve Link to comment Share on other sites More sharing options...
msh1 Posted July 13, 2016 Share Posted July 13, 2016 3 hours ago, steppenwolf said: That's a fortuitous solution, Graem. As promised, a circuit diagram and some photographs of my solution. Please note that this servo is close to the limit of its operational envelope so an A5 panel is probably the maximum it can cope with. This would be usable on a telescope with an aperture up to about 130mm:- Circuit Diagram of Control Relay Internal Layout Servo Linkage Front Control Panel that is brilliant thanks steve Link to comment Share on other sites More sharing options...
steppenwolf Posted July 13, 2016 Share Posted July 13, 2016 Quote Did you have a Mechano set when you were younger. I did and I loved it - I really wanted a Mamod Steam engine though but apparently the box wasn't very big and my dad assumed I'd be disappointed ...... Quote that is brilliant thanks steve Thanks, I hope the information is useful. 1 Link to comment Share on other sites More sharing options...
steppenwolf Posted July 13, 2016 Share Posted July 13, 2016 If you look at the circuit diagram, you'll see that closing the actuation switch turns the EL panel off (and opens the flap away from the telescope) - this is intentional although one would normally think of 'turning it on' on command! The reason for this is that at power-on, the servo will throw to the open switch position which it does at full speed which I don't feel is mechanically sympathetic so I arranged for the servo to be at the 'closed' position when fired up to obviate this. Now it is all calm and smooth and the controller has four speeds, manoeuvring (the one I use), slow, cruise and ramming speed .......... Link to comment Share on other sites More sharing options...
ollypenrice Posted July 13, 2016 Share Posted July 13, 2016 (edited) 9 hours ago, steppenwolf said: What do you do about dust control at Observatoire Per Frejvall, Olly? Very little, Steve. The occasional wipe, as the owners request. Dust on the objective has, in my view, no effect on flats. It is way too far out of focus. Flats seem to me to be affected primarily by dust very close to the sensor. Even filters are rarely affected, though sometimes they are. I don't know if you agree? Olly Edited July 13, 2016 by ollypenrice Link to comment Share on other sites More sharing options...
steppenwolf Posted July 13, 2016 Share Posted July 13, 2016 I agree that dust isn't a direct issue for Flats, Olly, it was more a question about just having dust on the optics which is something I try really hard to avoid but not for any 'technical' reason! I also have a fear of insects getting onto the lens surface and dying there - I check regularly especially when the pesky ladybirds are in residence ....... Link to comment Share on other sites More sharing options...
ollypenrice Posted July 23, 2016 Share Posted July 23, 2016 Of course I also run a protection racket: Pay an extra hundred euros a month or blackbirds may nest in your tube... Olly Link to comment Share on other sites More sharing options...
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