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Gina

Removing all unwanted parts of a DSLR to make a minimal weight and volume astro camera

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Found this thread today and was some very interesting reading. And some great ideas for the future :)

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HI all,  I know it's an old thread, but I'm in the middle of stripping my 550D of its mirror and ran into a bit of trouble with the shutter, and hoping someone here can help.  

While removing the shutter, its plastic backplate came off and one of the two tiny shutter leaf return springs popped off.  I have the spring, but I have no idea where it goes.  I was hoping someone happens to know, or has a shutter assembly lying around and could take a look. 

Here's the spring and shutter assembly:

 

 

IMG_1301.jpg

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This was very interesting to read. Maybe I also will disassemble my camera when it's old enough. My big problem is that the camerahouse give strong vignetting when I use my 5" f5.3 telescope. Most because of the mirror block the lightray on the upper side of the sensor (downside of image), but also the walls down to the sensor is too close to the sensor to let the lightray cone get to the edges and corners of the sensor without vignetting.

You can see here in the middle of my homepage how my masterflat looks, all edges are clipped because off this:

Sorry, the first link was wrong, this is the right one:

http://astrofriend.eu/astronomy/tutorials/tutorial-astroimagej/tutorial-aij-01-introduction.html

Or see the included image, it shows how much extra vignetting there is at top and bottom because of the camerahouse, but even left and right edges show traces of some unwanted vignetting that don't belong to the optic. The colors represent the level from 50% to 100% of the masterflat and my camera is a Canon 6D fullframe. Normally I crop my images when the signal is lower than 30% compare to center. That's out to the green area in the included image. But in this case the camera house's walls also give some reflexions that is hard to flat calibrate, upper side of this image.

Now my questions:

How does it look, is there material enough around the schakt down to the sensor so that I can widen the entrance without the camera fall apart?

I also read here that it's impossible to remove the shutter and its motor, couldn't the motor just be replaced by a resistor that simulate the motors electric load?

Another question, but maybe wrong place here, if I remove the IR and all the other filters above camera sensor then I also remove the dustremover, what I know the camera will give an err code and block the camera when the dustremover isn't there. Is there some way around this?

 

Thank you for sharing this information!

Best regards

Lars

 

masterFlatRed_cal_corr TS130 reducer0_75x_analyze.jpg

Edited by Astrofriend
wrong link

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On 08/05/2016 at 23:35, LarryC said:

HI all,  I know it's an old thread, but I'm in the middle of stripping my 550D of its mirror and ran into a bit of trouble with the shutter, and hoping someone here can help.  

While removing the shutter, its plastic backplate came off and one of the two tiny shutter leaf return springs popped off.  I have the spring, but I have no idea where it goes.  I was hoping someone happens to know, or has a shutter assembly lying around and could take a look. 

Here's the spring and shutter assembly:

 

 

IMG_1301.jpg

How about this? It's only a guess as I don't have one to check.

Image1.jpg

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Thanks for the suggestion.  I think you might be right, but I ended up assembling the camera without the spring and it works perfectly (I think).  I suspect the spring may be more important for the fastest shutter speeds so it may not be absolutely necessary for AP work. 

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Gina - thanks for the comprehensive instructions. I've got a spare 1100d or two, and high time I took the next step beyond filter removal. Getting nervous now!

 

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Glad if I can help :)  Good luck :)

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update - I've followed all your guide - thank you.  Really clear and easy to follow.  Had a slight mishap fitting a cold finger though - I think i've knocked off a couple of the pins - doesn't look like they are connected though, so I might be ok.  Have ordered another sensor (£30) from german ebay, so I have a spare if needed.

I'm now working on the enclosure, and trying to sort the peltier control with an arduino.

 

pics to follow.

Jim

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All the weight i took off my camera promptly went straight back on (plus a bit) with the peltier cooler...

Seems that my camera is suffering from the same expanding waistline that i am :D

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17 hours ago, Dave_D said:

All the weight i took off my camera promptly went straight back on (plus a bit) with the peltier cooler...

Seems that my camera is suffering from the same expanding waistline that i am :D

i know what you mean! I've got a whacking great heatsink hanging off it now, but at least it serves a purpose unlike all the extraneous parts of the camera that are now sat in a box.

 

I've never used arduino before, so enjoying the learning curve.  Just wish I'd paid more attention in my Electronic Engineering degree 15 years ago - I'm sure I did some work with microprocessor control... I've grabbed a copy of Njal's sketch from here https://ragnablade.myon.no/?page_id=84, just trying to get my head around it.

 

A combination of his guide, and Gina's, has been invaluable to me - if it doesn't work, I have to look closer to home for the guilty party!

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If you have a question about using an Arduino there's a fair chance I may be able to help - which I will be happy to do :)

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13 minutes ago, Gina said:

If you have a question about using an Arduino there's a fair chance I may be able to help - which I will be happy to do :)

thianks Gina - much appreciated!  If I can get the twins to sleep, I'll be trying to rig up a test circuit to connect an op amp to the PWM out, which will drive a jerry rigged DC/DC converter to power the pelter.  If I can get that bit working, I'm not too worried about the other side of it - even I can probably manage to work a one wire and a DHT11 :)

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