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Main
Date: 25 May 2007 01:57:10
From: bv
Subject: beginner questions on equipments
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Hello,
I need some advice on getting started with astronomy and astro-
photography. What sort of telescopes/equipments should I buy to start
this journey? I have a canon eos-20d digital slr and would like to
put it to use to take some night sky pictures: moon, constellations,
etc. and some day eventually, deep sky objects...
thanks a lot in advance,
bala
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Date: 25 May 2007 16:34:27
From: Steve Paul
Subject: Re: beginner questions on equipments
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"bv" <bala.variyam@gmail.com > wrote in message
news:1180083430.770461.268460@q19g2000prn.googlegroups.com...
> Hello,
>
> I need some advice on getting started with astronomy and astro-
> photography. What sort of telescopes/equipments should I buy to start
> this journey? I have a canon eos-20d digital slr and would like to
> put it to use to take some night sky pictures: moon, constellations,
> etc. and some day eventually, deep sky objects...
>
> thanks a lot in advance,
> bala
>
Constellation and "night sky" imaging can be accompished with a simple low
cost eq mount with a battery operated single axis drive. Nothing fancy, or
expensive is needed.
A remote exposure control (use bulb mode on your 20d) is a plus, but one of
the nice things about digital photography is that you can easily take
multiple short exposures and stack them in software. Multiple exposure
stacking has the benefit of helping cancel out camera sensor noise, and with
practice, stacking short exposures can work in your favor against light
pollution.
I don't know the 20d well, but the 300d allowed up to 30 seconds _without_ a
remote shutter release. 30 seconds grabs a lot of light with a standard
camera "kit" lens, which is very wide field when it comes to the sky. You
can take advantage of the camera's exposure timer delay, setting it to 10
seconds so you can press the button and get your hand off the camera,
letting it settle before opening the shutter.
All that said, the first thing anyone needs to learn about imaging the sky,
is how the sky moves, and around what point it rotates (the polar axis). An
equatorial mount has a polar axis which you align to the axis of rotation
around which all the sky moves. With the mount aligned to that axis, you now
only have to concern yourself with "clocking" and tracking the object as it
crosses the sky from east to west. (For a rudimentary method, Google on Barn
Door Tracker.)
Start there. Do not buy a telescope. Do not buy a fancy camera lens. Do the
barn door tracker thingy, or buy an inexpensive equatorial mount with clock
drive and learn how to set it up to track the sky.
Planet imaging at high resolution is best done with a long focal length
telescope (for increased image scale) and a (good quality CCD sensor) web
cam. Good tracking helps keep the planet on the camera's imaging sensor, but
it is not a critical issue because you are generally snapping frames in
movie format using a webcam at sub-second exposures, and then using software
to split the movie file into individual frames, sorting out the bad ones,
and stacking the good ones. You can manually re-align the planet on the
imaging sensor using the mount's clock drive controls before each capture
without too negative an effect, so even the alignment procedure can be
minimalist.
That said, long focal length telescopes are generally too heavy for the
inexpensive eq mount you're gonna use for constellation imaging. You'll need
to upgrade appropriately, which can start to get expensive.
Deep sky imaging is a WHOLE 'NOTHER BEAST at high resolution. Imaging of
small, dim, distant objects not only requires long focal lengths to increase
the image scale, but it requires exposure times up into minutes to collect
photons, which in turn means that tracking is now critical. Any variation
in object position on the sensor as a result of misalignment of the polar
axis, or as a result of clock drive tracking error, will cause elongation of
the stars (or any other of the brighter features) in the image.
The primary expense in deep sky imaging is in the necessary precision of the
mount's gearing, and motorization to keep the image dead nuts in the middle
of a set of pixels on the imaging sensor for long exposures.
When it comes to deep sky, there are lots of examples of bad tracking and
alignment, and failed attempts to image with cheap mounts, although few are
published. :-)
Enjoy!
-Steve Paul
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Date: 25 May 2007 08:29:41
From: laura halliday
Subject: Re: beginner questions on equipments
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On May 25, 1:57 am, bv <bala.vari...@gmail.com > wrote:
> Hello,
>
> I need some advice on getting started with astronomy and astro-
> photography. What sort of telescopes/equipments should I buy to start
> this journey? I have a canon eos-20d digital slr and would like to
> put it to use to take some night sky pictures: moon, constellations,
> etc. and some day eventually, deep sky objects...
>
> thanks a lot in advance,
> bala
Ditch the photography and learn to observe the sky first.
Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte
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Date: 25 May 2007 17:00:37
From: Chris L Peterson
Subject: Re: beginner questions on equipments
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On 25 May 2007 08:29:41 -0700, laura halliday <marsgal42@hotmail.com >
wrote:
>Ditch the photography and learn to observe the sky first.
Nonsense. We're talking about two different hobbies here, observing and
astroimaging. A person can be interested in either or both. There's
certainly no requirement that an astroimager have any interest at all in
visual observation.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 25 May 2007 14:40:08
From: Dennis Woos
Subject: Re: beginner questions on equipments
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>
>>Ditch the photography and learn to observe the sky first.
>
> Nonsense. We're talking about two different hobbies here, observing and
> astroimaging. A person can be interested in either or both. There's
> certainly no requirement that an astroimager have any interest at all in
> visual observation.
>
I agree with you - they are different hobbies. This is why I cringe when
someone posts that they would like some advice on a first scope, and that
they someday may want to get into astrophotograpy. For a lot of folks this
"someday" probably turns out to be "never", and can lead to either doing
nothing or some conbination of investing a lot of money and giving up in
disgust. I maintain that the best advice always includes seeking out a
local astro club, attending meetings and star parites, and seeing what each
activity entails.
Dennis
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Date: 25 May 2007 09:45:48
From: Brian Tung
Subject: Re: beginner questions on equipments
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laura halliday wrote:
> Ditch the photography and learn to observe the sky first.
Astrophotography is often an unrealistic goal for beginners, but I think
this is unnecessarily absolute (and it might sound a bit dismissive,
too). Lunar and constellation photography isn't that difficult, and
it can be done in conjunction with, rather than instead of, learning to
observe the sky. In fact, constellation photography may very well help
in learning the sky.
The Moon can be imaged afocally, basically by holding the camera up to
the eyepiece of the scope. In this case, any kind of scope will do.
Connecting the camera directly to the telescope, without any eyepiece
there, would eliminate most off-the-shelf Newtonians. Sine this kind
of telescope gives you the most bang for the buck for visual use, you
may want to defer this kind of photography.
Either of these kinds of photography is too magnified for most of the
constellation work; for this, you want to image with the camera by
itself, but to attach it to some kind of clock-driven mount, in order
to compensate for the Earth's rotation for any exposure longer than
maybe half a minute. This does *not* need to be a computerized
scope--you may want to call a reputable dealer to explain more about
this.
I have some information about this buried in MOPFAQ (link below), but
you can and should look at other FAQs that people post links to. Good
luck!
--
Brian Tung <brian@isi.edu >
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html
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Date: 25 May 2007 17:52:42
From: Mij Adyaw
Subject: Re: beginner questions on equipments
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"Brian Tung" <brian@isi.edu > wrote in message
news:f373rs$ufr$1@praesepe.isi.edu...
> laura halliday wrote:
>> Ditch the photography and learn to observe the sky first.
>
> Astrophotography is often an unrealistic goal for beginners, but I think
> this is unnecessarily absolute (and it might sound a bit dismissive,
> too). Lunar and constellation photography isn't that difficult, and
> it can be done in conjunction with, rather than instead of, learning to
> observe the sky. In fact, constellation photography may very well help
> in learning the sky.
>
I am not sure that astrophotography is such as unrealistic goal as long as
you have realistic expectations as a beginner. For example, Meade provides a
solution called the DSO that integrates a low-cost ccd device with simple
software and a telescope. This may be a good starting point for a beginner
that wants to do rudimentary imaging. You can also image planets. My images
of Saturn and Mars during opposition are excellent.
-mij
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Date: 25 May 2007 19:33:36
From: Brian Tung
Subject: Re: beginner questions on equipments
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Mij Adyaw wrote:
> I am not sure that astrophotography is such as unrealistic goal as long as
> you have realistic expectations as a beginner.
That was my point. Some beginners want to take breathtaking pictures
of the Rosette right of the bat--that's relatively unrealistic. But
lunar and constellation photography are *very* reasonable objectives,
even for a beginner. The right equipment--not expensive--is all the
original poster would need. Some of that equipment (non-Newtonians for
"prime"-focus work) is somewhat at odds with visual requirements, so I
think it's worth discussing that.
--
Brian Tung <brian@isi.edu >
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html
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Date: 26 May 2007 01:10:03
From: Chris L Peterson
Subject: Re: beginner questions on equipments
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On Fri, 25 May 2007 17:52:42 -0700, "Mij Adyaw" <mij@SpamBucket.com >
wrote:
>I am not sure that astrophotography is such as unrealistic goal as long as
>you have realistic expectations as a beginner...
I agree completely. Improvements in equipment and software the last few
years have made it possible for anybody to produce nice images without a
steep learning curve. Of course, there's room for vast development of
skills, but that's no reason somebody should be discouraged at the
outset. The same is true for many hobbies.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 25 May 2007 09:17:36
From: Shawn
Subject: Re: beginner questions on equipments
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bv wrote:
> Hello,
>
> I need some advice on getting started with astronomy and astro-
> photography. What sort of telescopes/equipments should I buy to start
> this journey? I have a canon eos-20d digital slr and would like to
> put it to use to take some night sky pictures: moon, constellations,
> etc. and some day eventually, deep sky objects...
>
> thanks a lot in advance,
> bala
Astromart has an active digital SLR astrophotography forum.
Start here: http://www.astromart.com/forums/
Shawn
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Date: 25 May 2007 06:50:01
From: Starlord
Subject: Re: beginner questions on equipments
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Telescope Buyers FAQ
http://home.inreach.com/starlord
--
The Lone Sidewalk Astronomer of Rosamond
Telescope Buyers FAQ
http://home.inreach.com/starlord
Sidewalk Astronomy
www.sidewalkastronomy.info
AD World
http://www.adworld.netfirms.com/
"bv" <bala.variyam@gmail.com > wrote in message
news:1180083430.770461.268460@q19g2000prn.googlegroups.com...
> Hello,
>
> I need some advice on getting started with astronomy and astro-
> photography. What sort of telescopes/equipments should I buy to start
> this journey? I have a canon eos-20d digital slr and would like to
> put it to use to take some night sky pictures: moon, constellations,
> etc. and some day eventually, deep sky objects...
>
> thanks a lot in advance,
> bala
>
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