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PostPosted: Thu Sep 06, 2007 1:02 am 
Thanks Bob for the link to your 'huge investment'

I must say that it looks incredible.
I had earlier imagined the camera attached to the eye-piece.

Now I know i am totally lost :oops:

Its a wonderful area of photography - makes us looks so minute in the world of the universe.

May give this (astro photography) a try in the future when my wallet is beefed up. :)

Hope to see your gear soon , Gordon.

David


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PostPosted: Thu Sep 06, 2007 1:38 am 
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DavidL wrote:
Thanks Bob for the link to your 'huge investment'

No problem. I've had the telescope for about ten years but I only got around to getting a decent mounting last year.

As mentioned before, for this thread I was holding the camera by hand while pointing it at the eyepiece. For my latest effort at "big sky" astrophotography have a look at this post.

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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PostPosted: Thu Sep 06, 2007 9:56 am 
I share David L's perspective on this subject - just when I thought I was mastering the 30D and 24-105mm set up I recently purchased I realise another whole new sphere of use for digital cameras/photography opens up. This looks like a fascinating subject - but as ever and as David pointed out one that is heavy on the wallet !
What would the two of you recommend as a "starter kit" as it were for astrophotography, as Bob looks to have gone the way of expensive telescopes whilst Gordon seems to favour attaching the camera and using prime focus methods ? I have used this format for slide copying using my old 350D coupled to a slide copier purchased from Jessops - but it cut off the outer of the slide - presumably the slide copiers work best with full frame cameras ?


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 Post subject: New hobby?
PostPosted: Thu Sep 06, 2007 11:02 am 
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Hi Simon,

I agree: it is a fascinating subject and it doesn't have to be mega-expensive to get started.

There may be some confusion about what I mean when I talk about the camera being at the "prime focus". When I use that term I mean that the camera is attached to the telescope in such a way that the image from the telescope's objective (main) lens is falling directly onto the camera's sensor. This is illustration (1) on the TeleVue™ Imaging Methods page. In fact, all the methods described on that page concern various ways to use a telescope to produce an image on a camera's sensor but then TeleVue™ are telescope manufacturers!

The cheapest way to start is to use the kit you already have. Have a look at Gordon's article Easy Astrophotography with normal DSLR equipment to see what is possible together with some excellent advice on how to achieve good results. Even here in the Northern Hemisphere the Milky Way is putting on a reasonable show if you can find a location with dark skies. Use the fastest aperture you have and a high ISO. As the camera is unguided use the widest field of view to minimise the appearance of star trails. Be patient because, unless you are very lucky, it will take a few practice shots to get the manual focus right.

I mentioned "star trails". You don't always have to avoid them. To see what I mean have a look at some of the images from this Google Images search.

If you want to take the next step up you still don't have to spend a fortune. I will quote one example from one UK retailer - N.B. I cannot vouch for the telescope. You can buy a small telescope on a motor driven mounting for £180/€270/$360 here in the UK. For product details have a look at this page. You would need to source (or make) a suitable adaptor to fix your camera on top of the 'scope and then you are set to go.

If you want to buy even a small telescope I seriously recommend using a specialist company owned and/or staffed by knowledgeable amateur astronomers who will make sure that what you buy is suitable for your needs. A good company knows that you are likely to come back in a few years for an upgrade!

Finally, don't get bogged down by the detail of all this. It is also fun just to get outside during a crisp clear night. Forget the camera, find a location with no nearby street lighting, take a good pair of binoculars and a comfy chair and lay back and wonder. Oh, and make sure the neighbours know what you are up to!

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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 Post subject: Shooting the Moon
PostPosted: Sat Sep 22, 2007 10:43 pm 
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Hi folks,

The first clear night for quite a few days here so I took my first opportunity to shoot the Moon with my EOS 40D at the telescope's prime focus.

Natively, the telescope has a focal length of 480mm at f/6.8 but I used a Powermate™ 4x "extender" to achieve an effective focal length of 1920mm at f/27.2. I had the 40D hooked up via an USB link so that I could control various shooting parameters from the notebook and also view each shot on a big screen as it was taken. In contrast to the technique described in my post First Light with the Canon EOS 40D this time I found it easier to focus using the camera's viewfinder.

The following shot is uncropped and was taken at ISO 800 with an exposure of 1/40th of a second. Mirror lock-up was enabled to reduce vibration and the shots were triggered using a remote release for the same reason. Post-processing was done using Canon's DPP program. The image is clickable if you want to download the 5.4MB full size picture.

Image

Yet again the 40D has shown how flexible a tool it can be. Though I chose to focus conventionally using the viewfinder I checked out the result using the EOS Utility's Live View Preview mode. That graphically illustrated how poor my choice of location was as with the Moon fairly low to the horizon and between two buildings it was dancing around all over the place. At least using ISO 800 allowed a reasonably short exposure time of 1/40th of a second in the hope of capturing an image during a brief moment of steady seeing. Ideally a bigger telescope objective than my Pronto's 70mm would solve a number of issues but as prime focus astrophotography isn't my main interest I will be content with what I have.

It was an interesting first effort but I need to wait for a couple of months before trying to improve. Then, here in the Northern Hemisphere, the Moon will be a lot higher in the sky and I can avoid the thermals surrounding the buildings and the generally poor seeing associated with any object fairly close to the horizon. Then I can hopefully reduce to ISO 400 and maybe get away with 1/30th of a second exposure. Then it will just be a matter of taking a long sequence of identical shots in the hope that one may capture the Moon during a brief moment of clear seeing. Then maybe I'll find out if the slightly soft image above was down to poor focussing and/or poor seeing or a more fundamental optical problem with my set up.

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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PostPosted: Sat Sep 22, 2007 10:48 pm 
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Hi Bob, impressive shot! I'll be posting some Lunar shots with the 40D soon, but I didn't achieve anywhere near the same focal length! The Powermate 4x - is it a 1.25in or 2in design? If the former, were there any vignetting issues?


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PostPosted: Sat Sep 22, 2007 11:12 pm 
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Gordon Laing wrote:
Hi Bob, impressive shot! I'll be posting some Lunar shots with the 40D soon, but I didn't achieve anywhere near the same focal length! The Powermate 4x - is it a 1.25in or 2in design? If the former, were there any vignetting issues?

Thanks for the kind words. My Powermate is a 2" diameter unit. On the Pronto the "gotcha" was that the focussing rack didn't extend out far enough so a 3" long spacer was needed (at extra cost) to put the Powermate at the right distance. Then, as usual with my prime photography, the camera had to be behind a 2" spacer to achieve focus. Having the camera on such a long lever can't be good for the telescope's focussing rack and a few trial shots without Mirror Lockup enabled set the whole thing vibrating nicely. :(

The 40D was the class act of the optical train. With hindsight the 4x Powermate is pushing the envelope a bit far with my little Pronto. It might have been better to go for the 2x unit and accepted a smaller but brighter image of the Moon.

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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PostPosted: Sun Sep 23, 2007 12:42 pm 
Hi Bob

Regardless what you mentioned about poor focusing or seeing..
I still think it was a very nice picture..impressive as Gordon put it.

and you got your notebook and pc linked working ! ( i assume)

Gordon
Hope to 'see' your gear soon.

DavidL


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PostPosted: Sun Sep 23, 2007 1:07 pm 
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DavidL wrote:
I still think it was a very nice picture..impressive as Gordon put it.

and you got your notebook and pc linked working !

Thank you for your kind words. As far as the USB link from the 40D is concerned, on the hardware level it has always worked. My only issue was trying to get the utility software to run on a notebook with 132MB of RAM, not to mention a 366MHz Pentium II processor. It looks like upgrading the notebook to its maximum :!: 256MB of memory has done the trick as the Live View Preview mode on the notebook's screen now refreshes a bit faster and downloading a RAW file plus Large Fine JPEG file each time the shutter is clicked, not to mention simultaneously displaying the thumbnails in the DPP utility, no longer results in so much disk thrashing that the notebook ends up crashing.

As the total cost of renovating the notebook was under £100 it turned out to be worthwhile but given you can buy a new Core 2 Duo notebook with 2GB of RAM and a 160GB hard disk with an OS installed for around £500 (€750/$1000) I wouldn't recommend taking the chance on buying a low specification used notebook for use with the 40D in the way I have described.

Bob.

P.S. Are you tempted you to rearrange the characters in your camera model number and drop the X. :wink:

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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 Post subject:
PostPosted: Mon Sep 24, 2007 1:12 am 
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Hi David, I've just posted a new video demonstrating Live View with my Televue Genesis scope... hope you enjoy it!

Gordon


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PostPosted: Mon Sep 24, 2007 8:11 am 
Thanks Gordon for that splendid video on Astro-photography.
Sure looks simple the way you showed it and put many things into prespective.

Some quick questions since I remember Bob mentioned that because the earth rotates , the picture must be taken in less than 20s unless you need to have those telescope with GPS which will auto adjust itself to prevent blurring.

a) how is it that you are able to take such a clean shot and where's the aperture control ? I think I read somewhere its a 'rated fixed aperture' which is not exactly same as camera f-numbers.
Maybe I am confused :oops:

b) When you increase the focal length and F-aperture without change to the diameter of the telescope - shouldnt there be less light and you need a longer time shot to capture the shot ?

Bob

Sorry for the confusion but I thought you wanted to linked your 40d mounted on the telescope to your notebook via USB and then have the notebook connected to the house pc to view and capture the stars from within the comforts of house and free of mosquitoes.

and Yes :D - tempted to drop my X as you put it. :P
But the wife will kill me first :!: :cry: :(

DavidL


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 Post subject: Great work
PostPosted: Mon Sep 24, 2007 9:06 am 
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Hi Gordon,

Great work on the videos and related still photography. It just shows what can be done when the "professionals" get to work. I look forward to trying to improve my own efforts.

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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PostPosted: Mon Sep 24, 2007 9:06 am 
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Hi David, since light gathering power is paramount for telescopes, none of them have an adjustable aperture setting - it's always wide open! So that's why you saw no aperture setting - you have to do this in manual mode and just adjust the shutter speed and ISO until you get the desired result.

My Televue has an aperture of f5.4, and a focal length of 540mm, so it's main objective measures 100mm in diameter. I had a 2x teleconverter on it for those Moon shots, so the working aperture was actually f10.8.

As for the Earth's rotation, my scope is on an equatorial mounting which can counteract it - but it wasn't setup 100% accurately that evening, so the objects still drifted a little...

Gordon


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 Post subject: Earth rotation
PostPosted: Mon Sep 24, 2007 9:24 am 
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DavidL wrote:
... I remember Bob mentioned that because the earth rotates , the picture must be taken in less than 20s unless you need to have those telescope with GPS which will auto adjust itself to prevent blurring.

Sorry for the confusion but I thought you wanted to linked your 40d mounted on the telescope to your notebook via USB and then have the notebook connected to the house pc...

I must have been having a bad hair day if I was talking about GPS and blurring. Certainly for long exposures using regular camera lenses you need to put the camera on a motorised mounting aligned with the Earth's axis to take away the effect of the Earth's rotation. For a relatively wide angle lens having the camera on a fixed tripod you should be able to get away with exposures as long as the 20 seconds mentioned without star trails becoming noticeable.

As for operating from within the house, I was just fantasising. With a fully remote controlled observatory (big bucks!) it would be useful but for us mere mortals having the notebook close to the telescope is the sweet spot as it allows optimal interaction at the tripartite telescope/PC/operator interface. Good grief, what have I just written - it must be time for breakfast! :roll:

Bob.

_________________
Olympus OM-D E-M1 + M.Zuiko Digital ED 12-40mm f/2.8, Lumix 7-14mm f/4, Leica DG Summilux 15mm f/1.7 ASPH, M.Zuiko Digital 45mm 1:1.8, M.Zuiko Digital ED 75mm 1:1.8.
Leica D Vario-Elmar 14mm-150mm f/3.5 - f/5.6 ASPH.
OM-D E-M5, H-PS14042E, Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.


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 Post subject:
PostPosted: Mon Sep 24, 2007 10:45 am 
Thanks Gordon for enlightening me :idea:

Sorry Bob if i mis-quote you on the GPS and blurring :oops:
Hope your hair day is back to nice clean and slick.. :lol:

Dinner time here Bob :wink:

DavidL


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