Compact digital camera - Astrophotography - prime focus method.

[Tamileniyan M]

hi,

I started with modifying my webcam for prime focus astrophotograpy, i could take nice pic of Moon, but am not happy with that, because long exposure was not possible also low resolution of the sensor.

so, I am trying to modify my compact digital camera (canon ps a1200) for astrophotography... prime focus method to get some deep sky objects captured.

I know, even if i do it, results will not be like DSLR but still wanted to do it.. i wanted to do something with cheapest available equipments.  I already have CHDK working with that cam for RAW, intervelometer, extended exposure and ISO etc..

did anyone give a such attempt to open a compact digital camera to modify it for prime focus astrophotography??? 

Thanks & Regards,

Tamil Eniyan

[pavan uttarkar]

Hi,

Instead of modifying you point and shoot you can use as it is, you can take pictures with A-focal method, I take picture through my point and shoot with the A-focal method and the results are also quite satisfying, I have been carrying out Astrophotography with my point and shoot from a year, but there are also some disadvantage like you can't go for deep sky with point and shoot, but you can try planetary imaging and also can take star trails etc. You can check out a A-focal adapter which you an get from Galileo Telescope Makers or from Tejraj, that can help you with Planetary imaging.

Regards,

Pavan.Uttarkar

[Tamileniyan M]

Hi Pavan,

I have been doing A focal, but its not satisfying. i hope the image will be better than A focal method, if i could rightly do prime focus. (IMO you need a good eyepiece for A focal, I dont have a good one, so planning to use my sensor as digital eyepiece for my 4inch reflector)

Thanks,

Tamil Eniyan

[Harshad RJ]

On Sun, Feb 2, 2014 at 10:55 AM, Tamileniyan M <mtamil...@gmail.com> wrote:

did anyone give a such attempt to open a compact digital camera to modify it for prime focus astrophotography??? 

AFAIK, you might be the first in this group to do so.

Best way might to get friendly with a local camera repair guy, and get tips from them. You might even find an old camera there on which you can experiment.

Just as an anecdote, I found a camera repair chap in my city and explained to him my astronomy interests. He turned out to be very interested too; so I conducted a little observing session for his family. Now I have full access to his shop, tools and camera spare parts ;)

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Harshad RJ

[Tamileniyan M]

 Hi Harshad, 

i have almost experimented the system, i removed the sensor attached with the flexi pcb and pointed it for prime focus during day time... and i could see sharp image though the colours where not natural as there is no filters... 

I have two ways of doing it, remove the sensor and try to attach to eyepiece adapter.

or

Remove the lens part of the camera and attach the eyepiece adapter on the camera itself. inplace of lens (which i want to)

But am sure.. that there is a feedback mechanism in the lens motor drive that detects the position of lens.. and if i remove the lens of the camera, my camera will just show lens error.. and do nothing else

i wanted to know if its still possible that if lens section is remove, still i can use the camera?

Thanks,

Tamileniyan

[keerthi kiran]

Hi Tamil,

I'm just thinking whether it's worth the effort. Some questions.

1. Does your point and shoot support Raw?

2. Does it support loooooong exposures (bulb mode)?

3. What is the size of the ccd/cmos chip does your camera have?

4. How will couple the camera with the telescope?

I'm guessing that the answers to 1 and 2 are NO and for 3, very small. So you will be able to use this modified camera only for planetary imaging.

Regards,
Keerthi

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[Tamileniyan M]

Hi Keerthi,

1. My point n shoot shoots RAW with CHDK
2. I can have exposures up to 60s usable, beyond that its noisy, may be sensor gets heated up a lot. I have intervalometer script running.
3.sensor is significantly smaller compared to DSLR. 6.2x4.6mm. But bigger than web Cam's. 
4. To couple, am planning to break open a eyepiece, remove the lenses, replace this sensor, camera body will be tied along with the focuser. Or planned to remove the lens section of camera body n place the eyepiece adapter, use a universal afocal adapter to mount the camera body coupled to the focussing tube.

Do u feel with this setup I can capture Orion with colour or m31..  ?? from a dark place??

Thanks,
Tamil Eniyan.

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[keerthi kiran]

With the small sensor, your FOV will be very small...

[Tamileniyan M]

oh ya.. thats a big limitation... 

But i still want to continue working on it....(i work only 1-2 hours per week on this)  i guess i will capture my first pic with this setup by march 1st week.

i have some limited expectations with this setup, i will be very happy if it comes out atleast to that level.

Thanks,

Tamil Eniyan.

[Harshad RJ]

On Sun, Feb 2, 2014 at 1:16 PM, Tamileniyan M <mtamil...@gmail.com> wrote:

i wanted to know if its still possible that if lens section is remove, still i can use the camera?

My guess is that these details will be model & firmware specific. Since you are  using CHDK, you might be able to override the lens check (if any) by yourself (if you tinker with the code or ask on their forums).

Why don't you try detaching the lens cables? Is it hard to insert / solder them back?

@Keerthi Small FOV by itself shouldn't be a problem, right? There are small and bright DSOs to go after. But the sensor may not fetch high SNR. I guess the optimum approach would be to take short exposures of bright DSOs. And to add a peltier cooler. (my arm-chair analysis)

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Harshad RJ

[Tamileniyan M]

On Monday, February 3, 2014 9:51:06 AM UTC+5:30, Harshad wrote:

On Sun, Feb 2, 2014 at 1:16 PM, Tamileniyan M <mtamil...@gmail.com> wrote:

i wanted to know if its still possible that if lens section is remove, still i can use the camera?

My guess is that these details will be model & firmware specific. Since you are  using CHDK, you might be able to override the lens check (if any) by yourself (if you tinker with the code or ask on their forums).

i will check on override lens option, thanks.  i personally like to remove the lens, rather removing sensor out of the cam body, so that the sensor will be protected inside the camera body and the pcb, lcd and buttons are also in the proper fitment. 

Why don't you try detaching the lens cables? Is it hard to insert / solder them back?

I wanted to take atleast one pic with this setup before it dies. i am afraid it will be difficult to put them back in place if i remove the lens cables... but i will certainly do it after my first average pic. 

@Keerthi Small FOV by itself shouldn't be a problem, right? There are small and bright DSOs to go after. But the sensor may not fetch high SNR. I guess the optimum approach would be to take short exposures of bright DSOs. And to add a peltier cooler. (my arm-chair analysis)

Having small fov is a limitation, i dont have a tracking mount. i should make sure that object is in fov for every shot. 

I have never used peltier cooler.. does it work efficiently?? i guess i need to have a big power bank to use it.

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Harshad RJ

[keerthi kiran]

Hi Tamil,

How much Zoom do you have in your camera? And, what is the actual (not effective) focal length of the camera lens?

Using CHDK, can you take long exposures with the existing lens itself and stack them? (Or if you share the frames, I can stack them and do some experimentation).

First, lets analyze the limitations of the sensor and the software(CHDK). Then you can do the mod...

Regards,
Keerthi

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[Tamileniyan M]

Hi Keerthi,

Below is the tech spec for Canon A1200

Type  12.1 Megapixel, 1/2.3-inch type Charge Coupled Device (CCD)

Focal Length 5.0 (W) - 20.0 (T) mm (35mm film equivalent: 28-112mm)

Maximum Aperture f/2.8 (W) - f/5.9 (T)

Shutter Speed  15 - 1/1600 sec. (Total shutter speed range)

Sensitivity Auto, ISO 80/100/200/400/800/1600

using chdk i have tried taking long exposures like 30s and tried stacking, it works.. but light frames are too noisy. 

I dont have the sample files right now. but i can try to capture some tonight. 

Thanks, 

Tamil Eniyan.

[Abhilash .P]

Greetings,

as regards to over-riding the lens check, please use extreme caution. So far a similar script has only been written for the Canon Powershot S3-IS.
http://chdk.wikia.com/wiki/UBASIC/Scripts:_Tele-Macro-Mode

 @Keerthi - yes, long exposures and stacking are both possible.

[Tamileniyan M]

finally.. i tried to remove the lens part, i detached the flexible pcb cable of lens section from the main board.

i turned ON,  got the lens error.

i fixed it back... and turned ON, there was some contact problem and the lenses moved in different directions and finally lost its positions. 

Now each time i turn ON my camera, i hear sound like machine gun firing. 

CHDK - Firmware upgrade method doesnt work at this time. i need to try direct method, if it works i have to work on neglecting lens error.. but am not sure if i can do that..

Now searching for some canon  old digi cam, to do it again, more carefully. :)

Thanks,

Tamil Eniyan.

[Saket Pofali]

The machine gun firing its due to the planetary(pun not intended) gears not meshing properly. Take a base position of the lens and then start assembly.