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Imaging - what am I getting myself into? Couple Q's


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So I've looked at the IMAGING forum on this website and I am -AMAZED- by what I've seen.

The question is.. how in the world are you guys getting photo's like that?

I have a Canon Rebel T3i, a lowly DSLR compared with the $'s I've seen on the camera's over there.

Will this camera get me any type of results as far as astrophotography, or do I need something more expensive? 

I was planning on getting something like this as a telescope:

http://www.amazon.com/Sky-Watcher-ProED-Doublet-Refractor-Telescope/dp/B004Q76Z5M/ref=sr_1_4?ie=UTF8&qid=1424991629&sr=8-4&keywords=apochromatic

I assume I also need a nice EQ base to go with this?

I'm just 'fishing' for info right now, I'll do a lot more research before I buy anything, but I already have the T3i.

Also, I keep reading about 'subs', etc. Can anyone explain 'briefly' how astro-imaging works, or point me in the direction? I didn't notice a FAQ in this forum. 

Thanks SGL!

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The short answer for getting really nice images is lots of money and dedication!

There are lots of people who image with a dslr and I have used one myself. They can produce nice images but don't like light pollution to much and can be quite noisy.

The first question you need to ask yourself is what do you want to image? Galaxies, nebulae, planets, widefield etc, they all use slightly different setups so having an aim will help you decide on future kit.

Deep space imaging uses the subs. You take an image of say 2 minutes exposure and this is a sub. You then take lots of subs of the same target Aiming for a few hours of total subs. These are then combined and processed into a single image.

Planetary imaging uses video. Most people start out with a modified webcam on a scope. The aim of this is you get 50 frames a second on the planet. You do this for a few minutes to get lots of frames. You use software to pick the best frames and then stack and process them into a single image.

Widefield imaging uses a camera and lens usually mounted on a telescope mount.

I'd recommend the book every photon counts as an excellent introduction as my post is quite basic in term of explanation. Have you any ideas what you would like to image?

It's also worth noting that most astrophotography relies on the quality of the mount. get a quality mount and work from the ground up!

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What's the reason for using subs? Is it because a single hour long exposure or something is impractical/impossible?

I'll definitely grab that book, right now I have the Backyard Astronomer's Guide (incoming in the mail) to get me started. 

As far as WHAT I want to imagine I think galaxies / cluster's  / nebulae would be what I want. I've noticed nebula's require filters, are the 'principles' the same for all of these objects (when compared to shooting planets or something?).

I noticed you said DSLR's don't like light pollution. I live in LA, but drive to a semi dark-sky site (can see everything in the little dipper with naked eye) to stargaze. 

Would my DSLR work out there under those conditions? What comes 'next' after a DSLR? I thought those were the big daddies?

Thanks!  

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MONEY, and several phases of trial and error that incorporate the spending of more money.

Also lots of time sat at a PC processing the data you have collected.

As you are in the US then you are looking, as you say, at a good mount, something to match the NEW6 here - I think that the Skywatcher AZ-EQ6 is available to you over there as well, bolt onto that a nice apo refractor try the WO GTF-81 or GTF-102 if still available, then the camera, that is a cooled ccd (not a DSLR you take those on holiday). Guessing that makes $7000. Then you will need a guide scope and guide camera - another $1000 say maybe $1200.

The good images are mono, that means a filter ring, not too bad $200 and a set of narrow band filters, say $1800 to round out the filter wheel.

Processing software, some is free but you will still need to buy some, Photo Shop seems one of the necessary for "good" results. Not sure what else but it is not uncommon to read of 6 different processing packages being used.

There is also the laptop to control all this and load the mono images to.

Imaging seems to come in sort of steps, you can have a budget setup for say $1200-$1500 with a DSLR but the next step is sort of 4x that, becaue in general you have to upgrade all items and each item is a fair increase in cost.

When it comes to AP it is a good idea to sit down and decide how far in to it you wish or intend to go.

A reasonable EQ mount with goto, small scope adn DSLR and a few other bits will allow you to get say 60 second exposures maybe 90 seconds with care on polar alignment and by stacking you can get reasonable images. But the really good ones it is a significant increase in the items/equipment required.

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The reason for using multiple shorter exposures is usually down to guiding and light pollution. As the stars move across the sky the scope has to track that. Even minute errors in the tracking and your round stars will looks like American football's, or even lines! it's better to get 4 15 minute subs than a throwaway 1 hour sub . A dslr will usually be limited by light pollution before the image is saturated beyond recovery. I'm in quite a light polluted area, my subs with a dslr were about 2 minutes each. My mono ccd I take 15 minute subs with a ha filter no problem.

Filters are used mainly for mono cameras. Mono sensors are more sensitive than colour sensors, you use rgb filters and/or narrowband filters to process a colour image.

The 'Daddy' cameras for dso work are mono Cooled ccd cameras. These won't have the chip size of a dslr but the noise they produce is minimal and the quality of image better. That's not to say you can't produce nice images with a dslr.

Under light pollution you can still image with a dslr but mono narrowband imaging will be lots better . You could get a light pollution filter for a dslr but they also cut out signal and it depends on what light pollution you have.

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MONEY, and several phases of trial and error that incorporate the spending of more money.

Also lots of time sat at a PC processing the data you have collected.

As you are in the US then you are looking, as you say, at a good mount, something to match the NEW6 here - I think that the Skywatcher AZ-EQ6 is available to you over there as well, bolt onto that a nice apo refractor try the WO GTF-81 or GTF-102 if still available, then the camera, that is a cooled ccd (not a DSLR you take those on holiday). Guessing that makes $7000. Then you will need a guide scope and guide camera - another $1000 say maybe $1200.

The good images are mono, that means a filter ring, not too bad $200 and a set of narrow band filters, say $1800 to round out the filter wheel.

Processing software, some is free but you will still need to buy some, Photo Shop seems one of the necessary for "good" results. Not sure what else but it is not uncommon to read of 6 different processing packages being used.

There is also the laptop to control all this and load the mono images to.

Imaging seems to come in sort of steps, you can have a budget setup for say $1200-$1500 with a DSLR but the next step is sort of 4x that, becaue in general you have to upgrade all items and each item is a fair increase in cost.

When it comes to AP it is a good idea to sit down and decide how far in to it you wish or intend to go.

A reasonable EQ mount with goto, small scope adn DSLR and a few other bits will allow you to get say 60 second exposures maybe 90 seconds with care on polar alignment and by stacking you can get reasonable images. But the really good ones it is a significant increase in the items/equipment required.

So if I sell my house and put my unborn children into slave labor I might be able to start taking pictures of the sky? 

Good info, I think my first 'goal' obviously is to start with what I got, $1200-2000 is probably my price range, I have no intent on taking $10,000 pictures, I just want to be able to see some galaxies in color. 

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The reason for using multiple shorter exposures is usually down to guiding and light pollution. As the stars move across the sky the scope has to track that. Even minute errors in the tracking and your round stars will looks like American football's, or even lines! it's better to get 4 15 minute subs than a throwaway 1 hour sub . A dslr will usually be limited by light pollution before the image is saturated beyond recovery. I'm in quite a light polluted area, my subs with a dslr were about 2 minutes each. My mono ccd I take 15 minute subs with a ha filter no problem.

Filters are used mainly for mono cameras. Mono sensors are more sensitive than colour sensors, you use rgb filters and/or narrowband filters to process a colour image.

The 'Daddy' cameras for dso work are mono Cooled ccd cameras. These won't have the chip size of a dslr but the noise they produce is minimal and the quality of image better. That's not to say you can't produce nice images with a dslr.

Under light pollution you can still image with a dslr but mono narrowband imaging will be lots better . You could get a light pollution filter for a dslr but they also cut out signal and it depends on what light pollution you have.

I suppose you can still get some cool stuff with 2 minute subs using a DSLR even with moderate light pollution? I take it the jump from price range is about $1500 with basic DSLR set-up to $5000+ as the other poster mentioned (with CCD?). 

The fact that CCD's are mono and that's why filters are so effective makes a lot more sense now, thanks. 

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Your camera on a camera tripod is capable of taking some nice pics. widefield and startrails are fine for this setup.

8560823914_7d966946b3_c.jpgMilky Way by Scott Prideaux 1961, on Flickr

And that's just the camera hooked up to a tri-pod? Still pretty cool, and I think I can get started on that right away.

So my take-away here is I can get decent stuff with a DSLR, assuming I find a great base and a decent apo scope? 

Thanks everyone. 

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I'd recommend getting the 80mm version of the Skywatcher scope you like plus also a matching focal reducer. You need to put it on a good tracking mount such as the heq5. Unfortunately that isn't sufficient. You also need a guide camera (which can be attached to the finder) plus cables plus a laptop to control it all plus various other bits and pieces. Of course, you also need something to power everything e.g. a 12v leisure battery.

You can see already how the $$$ soon add up... Fortunately, most of the software you need to start is free or low cost.

It's worth doing lots of research and studying before you jump in. Clear, dark skies are your friend!

Louise

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I'd recommend getting the 80mm version of the Skywatcher scope you like plus also a matching focal reducer. You need to put it on a good tracking mount such as the heq5. Unfortunately that isn't sufficient. You also need a guide camera (which can be attached to the finder) plus cables plus a laptop to control it all plus various other bits and pieces. Of course, you also need something to power everything e.g. a 12v leisure battery.

You can see already how the $$$ soon add up... Fortunately, most of the software you need to start is free or low cost.

It's worth doing lots of research and studying before you jump in. Clear, dark skies are your friend!

Louise

Thanks. It appears the only suitable thing I have so far is the laptop (Macbook Pro). 

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Camera on a tripod with a wide angle "fast " lens is great for wide field and Milky way. You can then get a 300-400mm telephoto with an EQ mount and do quite a lot if you are careful with setup and mount "tuning"

Taken with 12-28 lens at 12mm 30 x 10 secs

post-37593-0-62431800-1424997409_thumb.j

The rest are all taken with DSLR on an EQ tripod with a "soft" 400mm telephoto. Subs up to 300 seconds, none are guided.

M31

post-37593-0-52862000-1424997616_thumb.j

M33

post-37593-0-84659300-1424997566_thumb.j

M42

post-37593-0-99123900-1424997930_thumb.j

Sorry if I over-posted here. I want to encourage you to take one step at a time.

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Camera on a tripod with a wide angle "fast " lens is great for wide field and Milky way. You can then get a 300-400mm telephoto with an EQ mount and do quite a lot if you are careful with setup and mount "tuning"

Taken with 12-28 lens at 12mm 30 x 10 secs

attachicon.gifMW wide redo.jpg

The rest are all taken with DSLR on an EQ tripod with a "soft" 400mm telephoto. Subs up to 300 seconds, none are guided.

M31

attachicon.gifm31-drizzle-lr.jpg

M33

attachicon.gifm33-lr-pi-lr.jpg

M42

attachicon.gifm45-good stretch-cb-LR-2.jpg

Sorry if I over-posted here. I want to encourage you to take one step at a time.

Those are actually pretty spectacular, and honestly THAT'S the kind of stuff I would be satisfied with. 

So you're not using a telescope at all? Just a 400mm lens? I've noticed the big lenses (400mm) are about the same price as a good apo, think I'd go with the apo in the end. 

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I picked up my admittedly "soft" 400 mm Tokina on Ebay delivered $100. The older Tokinas are soft, the 12-28 I used for the first shot is a new Tokina and is sharp, as is the 100mm macro lens from Tokina I also use for semi-wide field.  There is something to be said for having the right tool for the job. Lenses can also be used for daytime photos.

The size of many common targets in the sky is surprisingly large. M31 is 3 times the width of the full moon. With targets like M42 and M45, either a tele lens or wide scope will do nicely.

Whether it's a tele lens or the refractors, lenses all suffer to a degree from CA. That's why I chose a Newtonian as my scope. Mirrors don't have CA. Reflectors have their own issues, it's a personal choice.

If you want to take truly wide field you can't do that with an APO, have to have a very wide angle lens, no more than 50mm. My 12-28 has a 90 degree FOV, my 100mm about 14 degrees. Lower f number the faster you'll get an exposure, thus avoiding trails.

I just bought a 6" reflector. It's a bit long to do unguided, IMO, so I bought a guiding kit too.

Getting that sorted is taking longer than anticipated.

Seems to be common.

Oh well, stars will wait for me.

An example of 14 degree FOV, with identity of items.

post-37593-0-94424400-1425006544_thumb.j

post-37593-0-16990400-1425006561.jpg

M6, M7, M8

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The very first one on a tripod was 30 x 10 seconds.

The 100mm shot was 60 x 2.5 seconds.

I used a $45 tripod, and be sure to have some sort of remote for shutter, or cable release at least.

Get Stellarium, or something like it. A great tool.

For lens photos, stop down at least one stop from open to reduce CA.

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The very first one on a tripod was 30 x 10 seconds.

The 100mm shot was 60 x 2.5 seconds.

I used a $45 tripod, and be sure to have some sort of remote for shutter, or cable release at least.

Get Stellarium, or something like it. A great tool.

For lens photos, stop down at least one stop from open to reduce CA.

Just for raw curiosity, what ISO are you using for say the 100mm shot? Aperture? 

I have a good tri-pod and Stellarium. Just need to read more about how to combine subs and all that, I haven't read much thus far (obviously) but this thread has intrigued me. Found some nice 400mm lenses on eBay for cheap as well, thanks for the heads up. 

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You have a dslr use that to start with.

The most important item will be a decent mount.

You don't even need a telescope as some camera lenses do a good job.

A dark site is preferable but don't let LP stop you, a decent LP filter will help.

Stacking subs increases signal to noise.

If your really interested in using a dslr spend a few bucks on this dvd by Jerry Lodriguss.

This dvd will give you all the info, with no hearsay, about using dslrs for AP.

http://www.astropix.com/GADC/GADC.HTM

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You have a dslr use that to start with.

The most important item will be a decent mount.

You don't even need a telescope as some camera lenses do a good job.

A dark site is preferable but don't let LP stop you, a decent LP filter will help.

Stacking subs increases signal to noise.

If your really interested in using a dslr spend a few bucks on this dvd by Jerry Lodriguss.

This dvd will give you all the info, with no hearsay, about using dslrs for AP.

http://www.astropix.com/GADC/GADC.HTM

Very cool, thanks. Only lens I have right now is the 18-55mm that comes with Rebel t3i; not sure how much I can get done with that. Guess I'll start looking for mounts. 

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Start with where you are. The zoom isn't as good as....fill in the blanks, but what's the harm with trying it? For avoiding star trails on a tripod, divide400 by the FL of lens. Some say 500, but I find 400 is usually good. So 20 secs and stop down one. ISO 3200 for a try, and use dark frames to help with the noise you will get.

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