Uses of a DSLR for astrophotography

Started Nov 3, 2012 | Discussions thread
DuncanDovovan
Senior MemberPosts: 1,277
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Re: Uses of a DSLR for astrophotography
In reply to eyeport, Nov 22, 2012

eyeport wrote:

Astrophotographer 10 wrote:

I am deeply into astrophotography and have been for about 8 years. Generally speaking if you get deeper into astrophotography you will find dedicated astro CCD cameras that are very expensive, expensive telescopes, mounts, filters, filter wheels etc etc.

But DSLRs play a role in this field that dedicated astro cameras have trouble filling and also are very good for getting great images early on.

DSLRs are great for:

1. Widefield nightscapes.

2. Night sky time lapses.

3. Imaging of brighter objects like globular clusters of stars.

They are not well suited to long exposure deep sky objects without being modified but still can do quite well up to a point.

14mm lenses are great for nightscape images of Milky Way, etc. Also for time lapses up to 35mm.

Vixen makes a very clever portable small tracking device called Polarie. It enables you to take longer than 30 second 14mm widefield images at night or use it to create a panning effect for time lapses. It costs about $500.

Most telescope manufacturers have adapters to make various DSLRs fit onto their telescopes (usually called t-thread adapters).

For urban imagers faced with light pollution you'll need a light pollution filter. Hutech sells a range of these and they are reasonably effective.

Deep sky imaging with DSLR usually requires a modified DSLR. Canon 350D modified was popular and a good 2nd hand one can be picked up for around $350. astromart.com is a place to find these things.

The usual UV/IR block filter blocks H alpha light emissions (a pink/red band of light). Nebula unfortunately emit in this band so your standard DSLR will not pick that up so well. Modified cameras (usually Canon EOS's) are very sensitive to that band and improve about 4 or 5X with a different filter installed - often a Baader, now there is an Astrodon replacement filter.

The original Canon 20Da was a model that worked in both daylight and astro imaging. Recently Canon released a 60Da model that is still current.

The mount is one of the most important parts of the setup as you will discover the stars whilst appearing motionless are moving rather fast as the earth rotates. Also being dark they require long exposures. So now we are imaging a dim object that is moving fairly quickly (15 degrees per hour).

Hence a highly accurate mount is going to be the main ingredient to happy imaging. Never skimp on the mount as elongated stars will be your constant battle. Getting round stars is step one. The rest is easy.

Feel free to ask me any question. I have been doing this a long time and know a lot about it and am happy to share my expertise.

Greg

Hi Greg,

I am a newbie for astrophotography and wondering about what equipments (lens/telescope, tracking amount, tripod) to get to get started. Besides doing wide sky galaxy shots I am strongly interested in deep sky. But first to get a quality sword of orion shot will make me really happy. I really appreciate your advice.

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Regards,
Felix Wu
Creationheart Photography
www.creationheart.com
Canon 1Dx, Canon 5D Mk3, 16-35L II, 35L, 85L, 100L, 135L, 70-200L IS II, 580EXII x2, PWplus3 x3, ThinkTank Airport Takeoff, Thinktank Retrospective LC3, Shootsac

I'm also a beginner. I want to learn the process of long exposing and noise reduction via stacking first using tripod wide angle shots.

I've also bought a Polarie tracker, that should enable me to make longer exposures or more towards tele.

As a next step I'm considering a Celestron 11" SC telescope, that would allow me to make photos at the view piece and, but also use Hyperstar to mount the camera in front of the telescope to do wide aperture wide photos. My NEX-7 is so small, that I think it will not block the view dramatically.

But at the moment I'm trying without a telescope first. When I see the pictures here in this forum that are being made with 50mm for example, I think there is a whole landscape of things to discover.

Deep Space does not always mean telescope, it can also mean long exposure without a telescope to make faint details visible.

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I'm a peaceful person looking for clarity and harmony and willing to help. If you believe my post had the intention to harm you in some way, you are probably wrong. =;-) Please verify first before assuming something bad happened to you. I can be a bit too brief at times. =;-)

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