Telescopes

On Aug 3, 3:36 am, amirs....RemoveThis@gmail.com wrote:
> I bought a Nikon D80 and I want to take pictures of the moon, planets
> and stars. Does anyone have any idea how I can use a telescope to take
> such pics? What do I need to use a telescope instead of the lens (the
> mount...etc)?

In addition to the T-Mount mentioned by someone else, there is
"eyepiece projection." In this method the camera is held by a bracket
so that it is exactly aligned to the center line of the telescope
optics. There are a number of folks selling these systems, some ads
in photo vendors catalogs, others in telescope catalogs.

To use eyepiece projection use a low power eyepiece on the telescope.
The higher the power of the eyepiece the smaller the diameter of the
exit pupil (the cone of light leaving the eyepiece). It is VERY hard
to align camera with a small exit pupil. You will get excessive
vignetting if the alignment is not almost perfect.
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On Aug 3, 3:36 am, amirs... RemoveThis @gmail.com wrote:
> I bought a Nikon D80 and I want to take pictures of the moon, planets
> and stars. Does anyone have any idea how I can use a telescope to take
> such pics? What do I need to use a telescope instead of the lens (the
> mount...etc)?

Exposure times for the moon will be fairly short, but for planets and
stars you'll need a telescope with an equatorial mount and motor drive
to track the image. Exposures for deep space objects could be pretty
long: several minutes or even hours for some things. With the D80,
you're limited to 30 second exposures, I think, but you can take
multiple images and combine them in post processing to get longer
exposures.

This website looks like it has all the information you'll ever need:
http://www.astropix.com/

(I'm not affiliated with the website in any way; I just did a Google
search for "astrophotography" and this was the first thing that popped
up. Still, it looks like a good place.)
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On Aug 3, 4:36 am, amirs....DeleteThis@gmail.com wrote:
> I bought a Nikon D80 and I want to take pictures of the moon, planets
> and stars. Does anyone have any idea how I can use a telescope to take
> such pics? What do I need to use a telescope instead of the lens (the
> mount...etc)?

I would strongly suggest picking up a good book on astrophotography,
otherwise you will end up with
mediocre results.
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<amirsamy RemoveThis @gmail.com> wrote in message
news:1186130167.718168.93560@22g2000hsm.googlegroups.com...
>I bought a Nikon D80 and I want to take pictures of the moon, planets
> and stars. Does anyone have any idea how I can use a telescope to take
> such pics? What do I need to use a telescope instead of the lens (the
> mount...etc)?
>
You should find Michael Covington's book "Astrophotograpy for Amateurs". He
describes 6 ways to get images from a telescope into a camera.

The simplest way just uses the telescope as a very long focal length lens.
For that, you need a tube and a T-mount. Both Celestron and Meade (just to
name a few) sell such gear.

I, however, use my 300mm f4 with a 2x converter to take shots of the moon.
I have found that, with iso of 200, 1/60 second with the lens wide open is
satisfactory. The resulting image is not quite big enough for my taste.

The image size of the moon is f/110. Hence, I only get a moon which is
about 6mm diameter. It needs to be bigger, but getting it bigger would
require spending money.

I mount the camera and lens on a Bogen 3021 tripod (not quite solid enough)
with a Bogen 3029 head. I use the self timer to eliminate as many
vibrations as possible.

Jim
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Mark Sieving wrote:
> Exposures for deep space objects could be pretty
> long: several minutes or even hours for some things. With the D80,
> you're limited to 30 second exposures, I think, but you can take
> multiple images and combine them in post processing to get longer
> exposures.

Or you just use BULB and time the exposure with your wrist watch.

Of course a remote control will help reduce camera movement.

jue
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As others have said, there are various ways of doing this a T-adapter,
eyepiece projection, Telephoto lens.

If you use a telescope, you will need a good solid mount that tracks.

You should be able to shoot the moon with a telephoto lens and tripod.
Most shots will be in 1/60 - 1/125 range depending on the moon's phase.

I wopuld suggest picking up the following books. they will help you
understand all that is involved with the hobby.

Digital SLR Astrophotography: by Michael A. Covington.

"Introduction to Digital Astrophotography: Imaging the Universe with a
Digital Camera" by Robert Reeves. He covers a ton of info from choosing
equipment to image processing.
http://www.optcorp.com/product.aspx?pid=105-258-259-261-7018


http://www.optcorp.com/product.aspx?pid=105-258-259-261-9231
How to Photograph the Moon and Planets with Your Digital Camera by Tony
Buick - OPT Telescopes

http://www.astropix.com/GADC/INTRO.HTM
A Guide to Astrophotography with Digital SLR Cameras


Then there is the post processing area which is a whole 'nother topic.

--
Remove My_Skin to E-mail me.


amirsamy.RemoveThis@gmail.com wrote:

> I bought a Nikon D80 and I want to take pictures of the moon, planets
> and stars. Does anyone have any idea how I can use a telescope to take
> such pics? What do I need to use a telescope instead of the lens (the
> mount...etc)?
 >> Stay informed about: Telescopes 

thanks to all. I really appreciate your help. I have the Nikon
18-200mm VR and i used it to take pictures of the moon in different
phases and the results were actually pretty good.. not great but good
enough.. and handheld believe it or not.. the VR helped for sure.. I
am sure if i use a tripod i would get way better results as i would be
able to lower the ISO and use a lower shutter speed. which would get
more details and lower noise.

>From what I've read I'm guessing the T mount would be the simplest,
easiest and most efficient solution. I looked up T mount for Nikon on
adorama and I found 2 of them. But now my question is would the T
mount that I buy work with any telescope? Or do I also have to match
the size of the eyepiece...etc. (I'm sorry I don't know much about
telescopes) .. also what do u mean by "a telescope with an equatorial
mount and motor drive".. links to actual products on adorama would me
help a lot to understand the difference thanks.
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On Aug 4, 10:06 am, amirs....TakeThisOut@gmail.com wrote:
> thanks to all. I really appreciate your help. I have the Nikon 18-200mm VR and i used it to take pictures of the moon in different
> phases and the results were actually pretty good.. not great but good enough.. and handheld believe it or not.. the VR helped for sure.. I
> am sure if i use a tripod i would get way better results as i would be able to lower the ISO and use a lower shutter speed. which would get
> more details and lower noise.
> From what I've read I'm guessing the T mount would be the simplest, easiest and most efficient solution. I looked up T mount for Nikon on
> adorama and I found 2 of them. But now my question is would the T mount that I buy work with any telescope? Or do I also have to match
> the size of the eyepiece...etc. (I'm sorry I don't know much about telescopes) ..
> also what do u mean by "a telescope with an equatorial mount and motor drive".. links to actual products on adorama would me
> help a lot to understand the difference thanks.

Telescopes commonly have one of two differrent tube sizes for fitting
eyepieces and accessories : 1.25 inch and 2 inch diameter. Depending
on which your chosen telescope has will determine which version of T-
mount to buy for best fit, although I'm sure you can actually get
adaptors for fitting 1.25 " accessories into the 2" tube.

Although one of the books mentioned in others' posts would go a long
way to illustrating in better detail, an equatorial mount is one of
the more common ways the telescope tube mounts onto the tripod /
support. Its main benefit is that you can track and follow the
movement of objects in the sky as the earth rotates more effectively.
>From the side view you have a cradle holding the actual telescope ;
the cradle is at the top of almost 'vertical' shaft which in turn is
fitted at right-angle onto a more 'horizontal' shaft, which rises from
the base part of the mount on the tripod. Actually, the vertical and
horizontal shafts are at a bit of angle from true upright and level.
Properly set up, they should relate to the latitude (degrees north /
south) of your viewing location .
Anyhow, the 'horizontal' shaft rotates about an axis called 'right
ascension' which is a bit like the longitude (east / west) of space
and the cradle on top of the 'vertical' shaft rotates about another
axis called 'declination' which is sort of like the latitude of
space
There are other variants of the equatorial such as the 'fork'
equatorial which are becoming more numerous and are generally used
with larger size telescopes, paricularly those in major astronomical
observatories .
Usually, a good equatorial mount will have measuring ('setting')
circles on each axis for you to accurately measure the exact right
ascension and declination positions of the star objects you're looking
at.

The motor drive is often a recommended option for the sake of
automatically driving the rotation of the equatorial mount to follow
the stars - as opposed to you having to stand there and manually move
the scope yourself ,which could be tiresome and inconsistent. Some of
the better telescopes such as Meade and Celestron are supplied with a
drive as part of the bundle.

Sugeest you look for a specialised telescope and astronomical
equipment supplier in addition to Adorama to view some examples of
scopes and equatorial mounts to get a better idea of what they're
like.
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<amirsamy RemoveThis @gmail.com> wrote:
>I bought a Nikon D80 and I want to take pictures of the moon, planets
>and stars. Does anyone have any idea how I can use a telescope to take
>such pics? What do I need to use a telescope instead of the lens (the
>mount...etc)?

Most people's advice has not been very good. Here's my version.

1) Yes you need a T-mount. They're cheap ($30) and you buy it for the
camera, not the telescope, since once you get one it'll work with most
decent telescopes. It basically just attaches a 1 1/4" tube to your
camera and most telescopes have either a 1 1/4" or 2" hole in which to
insert the tube. Fancier versions of this tube allow you to put an
eyepiece inside for higher magnification. They're only a little more
expensive.

2) The weight of the camera will be an issue with a small scope. Make
sure that any telescope you get has amount capable of supporting the
weight or that the scope can take counterweights.

3) Planets and the moon are fairly easy. You won't get anything like
what you've seen in magazines, but you'll be able to get decent photos
of Saturn's rings and Jupiters bands, and the like.

4) The hardest (imo) job of astrophotography is focus. Few SLR
focusing screens can handle really dim objects like stars and nebulae
and trying to see if a dim star is in focus is next to impossible.
There are gadgets avaible which make accurate focusing possible but
they're not cheap ($200+).

5) No, you don't _need_ an equatorial mount. Certainly not to start
and maybe not ever. For exposures up to 2-3 minutes a common
alt-azimuth mount will suffice, assuming that it's computer controlled
and can track. You can stack images for fainter objects.

6) Serious guys not only use a good equatorial mount, they also spend
money on autoguiders which do the job of keeping the scope pointed at
a star. No mount, no matter how good, will keep the scope pointed
at a sky object for a half hour or more needed for really dim objects.
But a good equatorial mount and a basic autoguider is a $1000
investment.

7) If you live in the city you will have to limit you photographs to
brighter objects. For some nebulae you can get a filter which blocks
most light except for the emissions of glowing nebulae.

This is a hobby which can produce great images, but it's pretty hard
and pretty expensive to do really well.

--
Ray Fischer
rfischer RemoveThis @sonic.net
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