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pixueto

Veil Nebula Canon 350D, 200P on EQ5 mod

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On the subject of sub length, see this thread for a very clever use of a range of sub lengths:

http://stargazerslou...t/#entry1659365

Thank you agnes. Very interesting thread. Anyone else there doing narrowband dslr astrophotography? The impression that I'm having is that in a light polluted area it's better to use an Ha filter with longer subs. Then short 3 min subs to add the colour and maybe no LP filter needed for those short exposures?

Edited by pixueto

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It seems to me that whenever you image an emission nebula you are doing narrowband imaging - the sensor might be broadband but the emissions aren't. So why not use a narrowband filter?

Saamir Kharusi, in addition to promoting short subs, also suggests the use of UHC filters to get both OIII and Ha simultaneously. The only drawback is the OIII is polluted with Hb light.

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Anyone else there doing narrowband dslr astrophotography?
Yes, I am - but not getting much chance to do any imaging due to the weather!

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Pix, I removed my IR filter tonight, it's not as bad as I thought it would be. I did need a large drink afterwards though.

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Interesting... So if you can get to 5 mins, you may as well carry on to 10, assuming you can take enough subs to smooth out the result. I've certainly learnt something.

Regarding 6x5min or 3x10min, I would think that both are not enough :-) but on a bright target, 6x5 has to be better, and on faint targets 3x10!

Are no, your wrong here! This is a classical mistake bases upon how we experience light in the day time. We receive so many Photon's per second that the real nature of light and Photon's is never perceived. Light (Photon's) arrive RANDOMLY in what is known as a POISSON distribution, so it doesn't matter; 3x10min is the same as 10x3min, expect for the additional READ-NOISE which is normally tiny compared to the other noise contributions. Therefore; 6x5min might be the idea compromise!

Finally, be careful with DSS; I moved away from it because it performs a deconvolution on the images before aligning them, this can work against you to emphasis noisy areas of your image. Not sure whether or not the current version still does this? And I use dedicated mono cameras now!

CCD Stack has a very interesting way of handling DSLR data; it converts it in to RED, GREEN & BLUE channels by debayering the sensor. This allows the data to be treated as though it came from a monochrome ccd camera, using all the advanced techniques etc...

http://www.stark-labs.com/craig/articles/assets/Debayering_API.pdf

Here is an article on the subject. Imaging with a DSLR has come along way since I started using one and you can get excellent results with a little care and attention.

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Pix, I removed my IR filter tonight, it's not as bad as I thought it would be. I did need a large drink afterwards though.

What camera are you using? I tried a couple of times with my Canon 350D but I can't manage to desolder the metallic panel protecting the filter!!!

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What camera are you using? I tried a couple of times with my Canon 350D but I can't manage to desolder the metallic panel protecting the filter!!!

Same as you a 350d. Sorry forgot, I used to have it in my signature.

I'm no good with a soldering iron and It didn't want to come out, but I got there in the end. One of the solder connections was very stubborn. Have you got a decent soldering iron, that gets hot enough? I used a solder pump too.

A couple of tips -

You'll need tweezers and a needle or pin for the ribbon cables.

I was very careful but still got a bit of dust on the sensor, some kind of blower or puffer would be usweful to blow off the dust.

Cutting out the filter with a stanley knife was one of the easier tasks.

Good luck.

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Same as you a 350d. Sorry forgot, I used to have it in my signature.

I'm no good with a soldering iron and It didn't want to come out, but I got there in the end. One of the solder connections was very stubborn. Have you got a decent soldering iron, that gets hot enough? I used a solder pump too.

A couple of tips -

You'll need tweezers and a needle or pin for the ribbon cables.

I was very careful but still got a bit of dust on the sensor, some kind of blower or puffer would be usweful to blow off the dust.

Cutting out the filter with a stanley knife was one of the easier tasks.

Good luck.

I think my iron was faulty and now have a decent one but, i got a feeling that those connections are really strong. I used wick but might need to go for a pump. I am terrified about damaging the circuit as last time I tried I was applying heat for quite a while. It's good to know that it can be done and that the connections can be stubborn as nobody mentions this in the tutorials and I was wondering what I was doing wrong.

The ribbon cables didn't give me much trouble up to the soldring step but I'd imagine that the next stage is quite tricky.

So, if you get some dust in the sensor you can just use a blower even thought there isn't any surface covering the chip? That's another load off my mind as I thought the sensor would be damaged permanently!

Thanks

Edited by pixueto

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I think my iron was faulty and now have a decent one but, i got a feeling that those connections are really strong. I used wick but might need to go for a pump. I am terrified about damaging the circuit as last time I tried I was applying heat for quite a while. It's good to know that it can be done and that the connections can be stubborn as nobody mentions this in the tutorials and I was wondering what I was doing wrong.

The ribbon cables didn't give me much trouble up to the soldring step but I'd imagine that the next stage is quite tricky.

So, if you get some dust in the sensor you can just use a blower even thought there isn't any surface covering the chip? That's another load off my mind as I thought the sensor would be damaged permanently!

Thanks

The connection on the last one was pretty strong, I did yank it a bit :-) I was worried about damaging the circuit too as I had the iron on there a long while. I don't think every part of the iron tip gets hot enough on my iron.

I'm normally a bit gun-ho with this sort of thing and it helped me this time. I had a worse time doing the hand controller, I think I read that you didn't find that too bad.

I'll put the link at the bottom of the page of the tutorial I used. I think it's the one Mark (QM) used.

The ribbons are just very fiddly when you have to put the circuit board back on, there are about 9 ribbon cables that need to go back in a certain order.

After the filter comes off, there is nothing covering it, I'll stick a URL on the bottom showing what it looks like. I used a blower, I'll see how well the camera works when the cloud goes :-)

Go on give it another go Pix :-)

Perry.

http://www.12dstring.me.uk/350dmod.htm

http://www.2mcctv.com/blog/2012_07_25-ccd-vs-cmos-image-sensor-technology/

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Yes, even though I'm very clumsy, I found the hand controller mod was easy and that gave me courage to try to remove the filter. Everything was going fine until I had to contend with the de-soldering bit. I was putting so much heat to the connections that I really worried about the circuit. I'll get a de-soldering pump and try again when my 5 year old son is not around in the house for... a good few hours!!!!

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Finally, be careful with DSS; I moved away from it because it performs a deconvolution on the images before aligning them, this can work against you to emphasis noisy areas of your image. Not sure whether or not the current version still does this? And I use dedicated mono cameras now!

CCD Stack has a very interesting way of handling DSLR data; it converts it in to RED, GREEN & BLUE channels by debayering the sensor. This allows the data to be treated as though it came from a monochrome ccd camera, using all the advanced techniques etc...

It appears I don't know much about DSS! I haven't heard this about DSS and deconvolution before. It does it before aligning? Are you sure? I can see how applying deconvolution on stretched data could lead to undesired results, but I didn't realise DSS applied any kind of pre-processing to the image files before stacking, does it...? There are various debayering options in the RAW settings of DSS, e.g. super pixel mode sounds like what you're describing.

Are no, your wrong here! This is a classical mistake bases upon how we experience light in the day time. We receive so many Photon's per second that the real nature of light and Photon's is never perceived. Light (Photon's) arrive RANDOMLY in what is known as a POISSON distribution, so it doesn't matter; 3x10min is the same as 10x3min, expect for the additional READ-NOISE which is normally tiny compared to the other noise contributions. Therefore; 6x5min might be the idea compromise!

Don't forget also that the SNR is higher with long exposures, so for faint nebulae longer exposures are desirable so long as the photon noise from your sky isn't swamping out the signal. (i.e. significantly higher than all other noise contributions)

Edited by Shibby
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Yes, even though I'm very clumsy, I found the hand controller mod was easy and that gave me courage to try to remove the filter. Everything was going fine until I had to contend with the de-soldering bit. I was putting so much heat to the connections that I really worried about the circuit. I'll get a de-soldering pump and try again when my 5 year old son is not around in the house for... a good few hours!!!!

My 2 and 4 year old were in the house when I was trying to do the Hand controller mod, I think that's why I had so much trouble with it. They were banging on the door of my office :-)

I had one dodgy soldered joint, hopefully most of your's will be ok.

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Well, I did try again last night. It took me two hors to desolder the metal shield but I didi it!!!. Everything seemed alright, didn't see any damage. Got to the filter, and I can't detache it from the camera body because I can't unscrew two of the screws. They are getting stripped and I don't want to make things worse. Anybody has been there before?

Oh Dear! What a nightmare this is becoming.

I've read somewhere that the screws are actually Japanese JIS and the philips screwdrivers are not good enough for this but, again, I haven't read about anyone encountering problems in this stage.

Edited by pixueto

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This is the screwdriver I've been using on the 1100D and I would think all the EOS cameras use the same screw heads :- http://www.amazon.co...ils_o02_s00_i00

I've been advised that this is the wrong size but I find it fits perfectly and the swivel top enables me to apply pressure while turning the screws. Although a bit pricey I've found it to be very high quality. I have used it probably hundreds of times to strip down and rebuild these cameras. I did get a set of Philips screwdrivers containing one that was supposed to be the right size but it wasn't quite as perfect a fit.

EDIT :- Looks likie this item is no longer available. :(

post-13131-0-12137500-1350162919_thumb.p

Edited by Gina

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Bl00dy hell Pix I think your 350d is cursed. You've been very unlucky.

Well done removing the soldered panel though.

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Surely it can't be the camera! It must be me being hopeless! Well, I ordered the JIS Japanese Industry Standard screwdrivers from amazon (another £20 - maybe I should've paid for the mod!) and I don't have much hope that this will work as the screws are already a bit stripped. I took the camera to mapplin todat to see if they had a screw extractor small enough for those screws but no luck. This is so frustrating!!!!

If that doesn't work, I've seem in the web precission screw stractors for £40. That would be the last resort abd if I get to that point, I would have spent:

-£20 solder iron

-£10 philips screwdrivers

-£20 Japanese JIS screwdrivers

-£40 precission screw estractors

-£3 dust mask

-£5 solder and wick

-£2 antistatic bags

So £100 (if I end up buying the screw extractors). I think that's what they charge you for the mod!!!

Well, I could say that I'm learning from the process and there is the satisfaction of doing it yourself but... it isn't clear at all that I'm going to succeed and I might end up damaging the camera.

Edited by pixueto

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I think most charge £150 for the mod but I may have mised one or two.

One idea might be to keep your 350D for normal terrestrial photography and buy a used 1100D for AP. The 1100D uses the Digic 4 image processor with lower noise, higher max ISO and 4x the luminosity range as the Digic 3. There is nothing to unsolder, just the usual dozen or so screws, ribbon connectors and filters to contend with. A Canon refurbished Rebel T3/1100D is available on ebay for just over £200 inc carriage from a UK seller and quick delivery.

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I think most charge £150 for the mod but I may have mised one or two.

One idea might be to keep your 350D for normal terrestrial photography and buy a used 1100D for AP. The 1100D uses the Digic 4 image processor with lower noise, higher max ISO and 4x the luminosity range as the Digic 3. There is nothing to unsolder, just the usual dozen or so screws, ribbon connectors and filters to contend with. A Canon refurbished Rebel T3/1100D is available on ebay for just over £200 inc carriage from a UK seller and quick delivery.

Gina, I've read somewhere that the 1100D is an entry level camera whereas the 450D is of higher quality. After reading this, I sort of assumed that the 350D is preferable over the 1100 D for astrophotography. Is this wrong then?

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The 1100D doesn't have some of the extras that are beneficial for terrestrial photography but of no benefit for AP, but still retains the important features used for AP.

I've just looked up the 350D and I find this is an old model and only uses a Digic II processor. This has been superseded by two newer image processors. These upgrades include Live View, shutter control and other functions via USB, reading the internal temperature, reduced noise level, increased max ISO, increased image data bits from 12 (4,096 levels) to 14 (32,768 levels).

I think the image filter also changed from one to two. The later cameras have two filters. One is a clear IR/UV cut filter and the other a colour filter which reduces red response. Earlier models combined these and removing this combined filter means you need to add an IR/UV filter for normal AP with any telescope or lens with glass in the light path. With the later models you can put the IR/UV filter back, just discarding the colour filter (which reduces the red from nebulae by 4 times).

The 350D has an 8Mpixels sensor whereas the 1100D is 12Mpixels.

Edited by Gina

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10 minute subs used to be fine for me in the winter months, especially with a bit of dither.

For reading out temperatures on RAW shots, you might want to try out Exiftool: http://owl.phy.queensu.ca/~phil/exiftool/

It'll pull out the temperatures for Canon CR2 images.

Once mine went above 18degrees the noise became an issue.

Anton

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You'll naturally get some if your polar alignment is really bad :)

Actually, now that I'm better at polar alignment, it's become more important.

I think most of the major capture tools can talk directly to PHD and send it dither requests (e.g. APT and nebulosity and backyard EOS), you only want to shift a tiny amount, a pixel or two.

I use MaximDL but can't seem to get it to ask PHD to dither.

Anton

Edited by badgers

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I think my polar alignment has improved lately. I've been using alignmaster and according to it I had a precision of arcseconds. How does it work the dithering? I would imagine that this will affect your focus or star shape? After all, you are sending commands to move the scope.

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Sorry Pix, I should have said. The dither commands come in between shots. Shoot an image, move a tiny amount, let PHD settle, Shoot next image.

With temperature matched darks it shouldn't make a huge difference, but on my DSLR it did really help as it was hard to have consistent darks temperature wise each night.

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