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otismetzler
2011-Mar-17, 07:08 AM
I'm looking into Astrophotography as a hobby, and I am looking into buying an entry level dslr for it. What dslr would you suggest I get, and what other accessories are needed?

Hornblower
2011-Mar-17, 12:10 PM
I'm looking into Astrophotography as a hobby, and I am looking into buying an entry level dslr for it. What dslr would you suggest I get, and what other accessories are needed?

I would start by finding a nearby astronomy club and picking their brains.

Do you have a telescope with a tracking mount that is robust enough to carry the weight of a camera? That is critical for anything beyond snapshots of the Moon or time exposures of star trails.

RickJ
2011-Mar-18, 01:46 AM
What's your visual astronomy experience and equipment you now own? What type of imaging? If planetary a video camera is far preferable to a DSLR as it takes 900 images a minute freezing seeing, sometimes when it is very good. Software finds, aligns and stacks those into one low noise image for further processing. DSLR can take only a dozen or so, all of which are likely not optimum. Then there's the mirror vibration issue.

DSLR does work for deep sky imaging. IR filter modified Canon models preferred as emission nebula emit mostly Hydrogen alpha light which is blocked by stock IR filters in these cameras. Hornblower's advice of finding a club with imagers to consult with is right on. They know your situation and what can be and can not be done in your area with a DSLR.

If you have no or visual astronomy knowledge that is vital. Spend a good hard year learning the sky, what can and can't be seen in it and how to find what you are looking for. Amateur astronomy has a steep learning curve, astrophotography an even steeper one. Together they make a vertical climb look easy. Over the years I've seen some try, all failed.

A useful book that should help, not anywhere near as much a club, is A Beginner's Guide to DSLR Astrophotography by Jerry Lodriguss.

For deep sky imaging, as Hornblower says, the mount is by far the most important item. More by far than the camera or telescope. I can take a good image with a cheap scope and camera but even the best camera and scope will take lousy images on a poor mount. Expect to spend a major portion of the budget here. A great mount for visual work can be nearly useless for deep sky imaging through a telescope. Also for anything more than using the camera and lens atop an equatorially mounted scope you will need a second camera and way to guide. Only very pricey mounts ($10,000 and up) can track for more than a minute or so without guiding. Far cheaper to guide! Many mounts fine for a small scope visually can't do this task as they don't have guider inputs.

Rick

otakenji
2011-Mar-20, 05:11 PM
Basically, you will need lots of money, too. Astrophotography is not cheap.

RickJ
2011-Mar-20, 06:31 PM
Not necessarily. I started using a home made barn door drive platform and simple SLR camera. Worked well for wide field images. I got great shots of several comets as well. Later I improved it adding a wind up alarm clock mechanism to turn the drive screw relieving me of that tedious task. Camera cost me $25, the rest came from junk I found around the house.

Now 60 years later I've got about the same as a good car cost in my system and the knowledge to use it. Start slow and grow your gear as you gain the knowledge to use it. Many years ago then editor of the US Astronomy Magazine, Richard Berry coined the term for those who jump in the deep end buying all the expensive gear without the knowledge to use it; "Ninty Day Wonder". Saw a few too many of those over the years. Slow and steady gets you there and allows the bank account time to breathe.

Rick

Barabino
2011-Jun-13, 05:34 AM
Ok, I'm a beginner and I've just started tinkering with a celestron refractor (NexStar 102 slt)...

http://images.pricerunner.com/product/image/419482/celestron-Nexstar-102-SLT.jpg

I'd like to take some shoots of the Moon...

Just to start, I've bought a cheap USB eyepiece...

But... !

1) I know that USB is unreliable: a device may work now, but it will not next time I install MS Windows again :-( (not to mention linux, Mac...)

2) usb cables are just 5 metres long (I would like to put the telescope in my backyard and to use my desktop computer indoor -- NOT a portable computer standing by the telescope)

do you know any eyepiece with an RCA analog video connector or S-VHS connection?

http://upload.wikimedia.org/wikipedia/commons/9/91/Composite-cables.jpg

http://upload.wikimedia.org/wikipedia/commons/thumb/5/55/S-video-connection.jpg/800px-S-video-connection.jpg

If I had a s-vhs eyepiece, I would not need any special software driver -- just a good video acquisition card... :-)

RickJ
2011-Jun-13, 06:07 AM
USB is quite reliable if it has decent drivers and hardware. Nearly all top CCD cameras costing into the 5 figure range use it. Video has very low resolution by comparison to a good web cam. Such cameras are available but give poor results compared to what you have. Though your scope is your biggest limiting factor. For high quality video imaging you need as much light as possible for fast frame rates. Moon is forgiving due to its slow motions and you can integrate images over several minutes time. Idea is to get a thousand or so then use software like Registax to sort and give you the best 100 or so which are combined into a low noise image software can process further to bring out fine detail. This isn't possible with RCA video. Well it is but the results are very poor by comparison.

USB is limited to 5 meter cables unless amps are used in line. Then it can reach 15 meters or so with good results. Beyond that you have to convert the signal to something that carries further. I use Class five wiring and a USB converter at each end. For USB 2 these cost over $300 so aren't cheap. Nor is a good camera for this such as the Flea and a few others. Most work at the telescope. Remote operation is fine for far more expensive systems than yours but not for this system.

Rick

Barabino
2011-Jun-14, 10:58 AM
Ok -- I do have a laptop, but I fear to pollute it with crappy USB drivers...

but if this is the way everybody does it, sigh!, I'll comply...

Thanks a lot! :-)

TonyE
2011-Jun-14, 01:34 PM
I think the easiest way to get started is with a webcam. I use the SPC900NC with a telescope adapter (including an IR filter). I use Registax to stack and process the video. Quite reasonable results are possible with the Moon and brighter planets.

Barabino
2011-Jun-21, 05:14 AM
yes, an USB eyepiece

is just a webcam without optics, just the sensor (ccd? cmos?)


and it seems I've been lucky...

the usb drivers and app look decent enough! :-)

(although not astronomy-specific)

Arcsoft webcam Companion