dslr chip size???

[cosmicdonkey]

Hi guys i have been using an orion g3 osc as a starter camera for getting into deep space imaging. It seems to work ok but i tried shooting m42 the other day and was very dissapointed as the nebula barely would fit in the frame:( 

I have been looking at the canon 1100d as an upgrade (would love a big expensive ccd but funds wont allow) Would i be right in thinking that with a larger chip size i would increase my field of view or is my telescope the limiting factor? I use a celestron c9.25 with focal reducer.

Or is there any other camera you think would be better with a £500 budget. thanks in advance for any comments  

[Alveprinsen]

Hi guys i have been using an orion g3 osc as a starter camera for getting into deep space imaging. It seems to work ok but i tried shooting m42 the other day and was very dissapointed as the nebula barely would fit in the frame:( 

I have been looking at the canon 1100d as an upgrade (would love a big expensive ccd but funds wont allow) Would i be right in thinking that with a larger chip size i would increase my field of view or is my telescope the limiting factor? I use a celestron c9.25 with focal reducer.

Or is there any other camera you think would be better with a £500 budget. thanks in advance for any comments

DSLR all the way baby, unless you want to fork out 4000 pounds for an equally sized CCD chip.

The idea thing would be to get a modified one... Like one of these JTW Ultimate Deep Cooled Canon cameras... However, they cost like more than twice your budget. But even an un-modded Canon EOS camera will give you great results. They will have more noise than a CCD picture, but they will be a hell of allot larger... And your FOV will in comparison to your current camera be - for the lack of a better term: clinically insane.

I never went the CCD route, and I havent regretted it. I grew out of my unmodded Nikon D3100 DSLR pretty quick though, so I've ordered the camera I mentioned above, only with the 600D instead of the 1100D. But if I were you, I would totally go for that Canon... Upside is, if you've got nimble fingers - you can mod it yourself. There are plenty of DIY tutorials on YouTube and such. If not - you can allways send it in to some modifying service, and get it done at an extra price. Hell, when economy permits, you could even turn it into a Ultimate Deep Cooled one. I know they provide that service...

Anyhow... DSLR baby... all the way. Although you should expect naysayers telling you to stick to those itsy bitsy teeny tiny CCD chips...

Sincerely, Alveprinsen.

[Quatermass]

Go for a second hand cannon 350d and mod it yourself body only dead cheap and a brilliant camera tool all my images with it see my blog for the pics and what this little gem can do. Modding it by removing the filter is not too hard or pay some one to do it for you i did it myself and im terrible at soldering and electrics

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[ollypenrice]

The C9.25, even reduced, has a long focal length so you do need a biggish chip for many targets. It will maybe not cover the Canon chip perfectly but you should get a large clean area.

DSLRs are noisy so they thrive on fast F ratios and low temperatures. Still, I think you're going down the right road with a Canon.

It will be good to read what Alveprinsen has to say about the highly modified camera when he's had it under the sky. 

Olly

[sharkmelley]

I am a great fan of DSLRs - a Canon 350D (with the internal filter removed )is still my main imager.  If budget is your main limiting issue then a DSLR is no-brainer.

However, from my experience I should point out the following couple of points.

The C9.25 is still a slow optical system even with a focal reducer.  This means that without cooling, you will probably find that thermal noise becomes the limiting factor in your images in the Summer and mild Spring/Autumn evenings.  I think an uncooled DSLR is ideally paired with a fast scope.

I also think you will quickly find you want to mod the camera for H-alpha sensitivity.

Mark

[JohnC64]

I've been using a 1100D now for a couple of years.  I bought it modified and it has been great.  As you say the chip size is APS-C which gives a lot of area.
In terms of noise, i  find that during the winter, it is not a problem.  During the summer, i tend to knock the ISO down  to ISO 400 which seems to help.  Because of its popularity as an astro camera, you will find plenty of add on extras, like clip in filters, TMount adapters etc readily available 

One thing to note is that the DLSR does  do some internal processing on the images so if you look closely you will find some dark halos around stars( only if you zoom into the pixel level do you see them)  I also notice a very slight "red shadow"  on very bright stars(especially on red stars). probably caused in part by having the mod with a shim so that autofocusing still worked.  If this is going to be an Astro camera only then you probably don't need the shim.

I've only used this camera at around the f5  mark and it performs well.  At f10 on the c9.25 then your sub time will have to be longer to gather the same detail - Or an alternative way of looking at it is that your signal to noise level will be lower so noise will become more of a factor.

There are plenty of  adverts for modded canons on astrobuysell  for around about £250 - £300 so you may be able to pick up a bargain on there.

John

[ollypenrice]

I am a great fan of DSLRs - a Canon 350D (with the internal filter removed )is still my main imager.  If budget is your main limiting issue then a DSLR is no-brainer.

However, from my experience I should point out the following couple of points.

The C9.25 is still a slow optical system even with a focal reducer.  This means that without cooling, you will probably find that thermal noise becomes the limiting factor in your images in the Summer and mild Spring/Autumn evenings.  I think an uncooled DSLR is ideally paired with a fast scope.

I also think you will quickly find you want to mod the camera for H-alpha sensitivity.

Mark

You have an Epsilon and, at F2.8, DSLRs really can perform close to CCD levels on many targets. At more mundane F ratios I'm firmly of the CCD persuasion. But they cost.

Olly

Edited November 15, 2013 by ollypenrice

[sharkmelley]

You have an Epsilon and, at F2.8, DSLRs really can perform close to CCD levels on many targets. At more mundane F ratios I'm firmly of the CCD persuasion. But they cost.

Olly

Exactly right.  At fast F-ratios, unless the sky is pristine, the only real difference in quality between a DSLR and a cooled one-shot-colour camera is down to the quantum efficiency of the sensor.  At slower F-ratios the OSC has a clear advantage unless the DSLR sensor is cooled. So it makes me very interested to see how the JTW performs - though I think the cooling has been taken to the extreme!  For narrow band imaging the choice is obvious - it has to be a cooled mono CCD.

Mark

[cosmicdonkey]

Thanks guys for all your comments what would you recommend as a good fast scope to complement the dslr. Just building a picture of future purchases I will go the dslr route thanks to the positive comments.

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[ollypenrice]

Exactly right.  At fast F-ratios, unless the sky is pristine, the only real difference in quality between a DSLR and a cooled one-shot-colour camera is down to the quantum efficiency of the sensor.  At slower F-ratios the OSC has a clear advantage unless the DSLR sensor is cooled. So it makes me very interested to see how the JTW performs - though I think the cooling has been taken to the extreme!  For narrow band imaging the choice is obvious - it has to be a cooled mono CCD.

Mark

There is also the matter of bit depth, which is why decent star colour from DSLRs is rarely seen, though it is sometimes seen. Whatever you do to a DSLR it cannot match a CCD other than on price.

Olly

[old_eyes]

...

One thing to note is that the DLSR does  do some internal processing on the images so if you look closely you will find some dark halos around stars( only if you zoom into the pixel level do you see them)  I also notice a very slight "red shadow"  on very bright stars(especially on red stars). probably caused in part by having the mod with a shim so that autofocusing still worked.  If this is going to be an Astro camera only then you probably don't need the shim...

John

General advice is always to use the RAW file format to avoid the internal processing of the DSLR. I always set my 1000D to maximum resolution JPEG + RAW. This allows me to use the JPEGs for checking how things are going and for selecting out poor frames, and the RAW files for actual processing. Deep Sky Stacker handles Canon RAW format OK as does Astroart. I use APT for camera control and data acquisition, and a little converter that let's me run the Canon off the 12V powertank for increased battery life.

Old_ eyes

[Scott]

I know a bloke who owns a JTW 1100d (serial # 001) and he seems to be getting some pretty fantastic results. having said that, they cost a damn sight more than your standard 1100d   .

It always comes down to money .

Edited November 17, 2013 by auspom

[jambouk]

Old-eyes, do you have any pictures of the power supply for your canon? I'd love to run mine off the 12v supply.

James

[sharkmelley]

There is also the matter of bit depth, which is why decent star colour from DSLRs is rarely seen, though it is sometimes seen.

Bit depth is a valid point.  But in practice it is not too much of a problem.  I will often take a few shorter exposures with no saturation of the brighter stars.  The stack of shorter exposures is then combined with the stack of longer exposures to form an HDR stack before the main post-processing sequence begins.  Thus there is no loss of image quality but it does increase the data acquistion time.

Mark

[ollypenrice]

Thanks guys for all your comments what would you recommend as a good fast scope to complement the dslr. Just building a picture of future purchases I will go the dslr route thanks to the positive comments.

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The problem with good fast scopes is that they're darned expensive. A cheaper scope with a CCD might end up at a similar cost and, in my view, a long way ahead. However, if you aim for F5 to F6 after the FF/FR you would be in affordable territory with the small refractors.

Olly

[old_eyes]

Old-eyes, do you have any pictures of the power supply for your canon? I'd love to run mine off the 12v supply.

James

I use adaptor from www.astronomiser.co.uk. They have one for all types of Canon DSLR that astrophotographers use. Cigar lighter plug, short cable, little grey box of magic, short cable, and battery case with connections. Just plugs into your normal battery space in camera. No problems over two years. Just works every time.

old_eyes

[jambouk]

Thank you.

James

[Science562h]

DSLRs, without 'scope, would still be an upgrade to a G3, just by being able to take widefield exposures. The G3 & G4 are too narrow field & you can't snapshot, with included software. I'm looking into upgrading my Sony CCD DSLR, which I prefer, over the G4. 

[Stu]

17 hours ago, Science562h said:

DSLRs, without 'scope, would still be an upgrade to a G3, just by being able to take widefield exposures. The G3 & G4 are too narrow field & you can't snapshot, with included software. I'm looking into upgrading my Sony CCD DSLR, which I prefer, over the G4. 

Just keep an eye on the age of the threads you are posting on. This one dates from 2013 so I imagine things may have moved on a bit since then.