Night sky images?

[mcrossley]

For anyone else who fancies a try at webcamming with a telescope, Morgan Computers are doing bundles on the Philips web cams (which have the very sensitive Sony EX-HAD CCD sensor)

Basic web cam £15

Web cam plus 1.25" adapter and IR blocking filter £36

Adapter on its own £10

IR blocking filter £13

They will also perform a firmware upgrade on the web cam for you (though it is easy to do yourself) to remove the in-camera image processing, which leaves a better image (less artefacts) for later processing after stacking.

[steve]

Mark, could you recommend a not-too-expensive adapter to connect a DSLR (EOS 300D) to a telescope (Meade 114/900 EQ1-B)? It's something we keep meaning to have a play with but haven't got around to it yet.

[mcrossley]

Steve, I think you will have to do it in two stages.

First you need an EOS to T-Thread adapter, these can be picked up on eBay for a few pounds now - usually from China!
Expensive version
eBay version
Make sure you get a T2 T-thread adapter though, not a Pentax. They are both M42, but the thread pitch is different.

Then you will need a T-Thread to 1.25" push fit - I don't think the Meade 114 has a 2" focuser?
Like this one but I would google it to find the best deal

[mcrossley]

With a 1.25" adapter you are going to a fair amount of vignetting on an APS sized chip, so be prepared to crop your images a bit! With dSLRs a remote release is a godsend, as is mirror lock as it reduces the vibrations - just wait until you try doing this stuff!

[Gina]

For anyone else who fancies a try at webcamming with a telescope, Morgan Computers are doing bundles on the Philips web cams (which have the very sensitive Sony EX-HAD CCD sensor)

Basic web cam £15

Web cam plus 1.25" adapter and IR blocking filter £36

Adapter on its own £10

IR blocking filter £13

They will also perform a firmware upgrade on the web cam for you (though it is easy to do yourself) to remove the in-camera image processing, which leaves a better image (less artefacts) for later processing after stacking.

Thanks for the info Mark I have a Philips Vesta webcam on order (from Amazon) which several people have adapted for long exposures. I also have a CCTV camera with a Sony Super HAD 1/3" sensor which is very sensitive (0.001 lux). I haven't got that one set up for the telescope as yet but do have it set up for my old Pentax film SLR camera lenses. Works beautifully with the 55mm, f1.8 standard lens. I've been using the MS Lifecam HD sensor for moon shots (last time the moon was visible). Not enough magnification for the planets and I imaging not sensitive enough for deep sky objects.

Not had any clear skies for several days nor are we likely to have for several days more, so night sky viewing and experimenting is on hold

[steve]

Steve, I think you will have to do it in two stages.

Thanks, I'll see if I can get it sorted at last.

[Gina]

Mark, could you recommend a not-too-expensive adapter to connect a DSLR (EOS 300D) to a telescope (Meade 114/900 EQ1-B)? It's something we keep meaning to have a play with but haven't got around to it yet.

I've recently bought a Sony A200K DSLR camera second hand, but good as new, for under half the new price. If I'd had plenty of money I'd have bought a new Canon DSLR. I'm hoping to use the Sony for astrophotography and have bought T-adapter (1.25" to fit the telescope) and Sony adapter ring (to connect Sony camera body to T-adapter), so we'll see. I also have a digital camera mounting bracket (to mount any camera with tripod bush onto the telescope focus tube) which I tried with my old Canon PowerShot S40 and the telescope lenses, but had considerable vignetting. Using a DSLR without lens with the sensor at prime focus is considered to be much better, I've read - hence the T-adapter and adapter ring to fit the body lens mount.

Since I got the camera second hand it was missing the battery charger and cables, so I've got those (plus a spare battery and bigger CF card) on order, so I haven't been able to try it yet. Hoping they come today.

[Gina]

Just arrived in the post :- Philips Vesta webcam, Sony compatible battery, charger and video cable So I shall now be able to charge the battery and try out the camera. It's not just for astrophotography but general photography too. I've wanted a DSLR for some time but not been able to afford it so been using a point-n-shoot digital camera. I used a Pentax Spotmatic film SLR for many years but got tired of spending umpteen hours in the darkroom developing film and printing photos. Digital is so much easier and more flexible! But I've missed the versatility of an SLR - I had several lenses for the Pentax and various adapters.

[Gina]

Tried my Sony A200 camera with adapter ring + T-adapter on my telescope (Celestron Astromaster EQ 130 MD) but it's no good - the focal plane of the telescope is, in fact, actually inside the T-adapter I should have checked that. In fact I've already made a holder for my MS Lifecam sensor and, yes, it had to go right inside the T-adapter. So I should have known, if I'd thought about it! I tried putting the camera body sans adapters close up against the focus tube and tried to focus - using distant trees about a mile away and found I couldn't get the focus tube in enough to focus the trees I don't know if any other DSLRs and thinner in the body - front to image plane is about 2" with the Sony.

Conclusion - you can't use a Sony A200 DSLR with a Celestron EQ 130 for focal plane astrophotography! A different camera and/or a different telescope may well work. Now I'm wondering about possibly using a diverging lens to increase the focal length of the telescope.

[mcrossley]

Gina, Newtonian scopes with the focal plane inside the focuser are a problem for astro imagers. One solution is to move the primary mirror 'up' the tube a bit, either by moving the whole mounting, or sometimes there is enough adjustment in the collimation screws to push the mirror further up. Either way you have to make sure that there is enough travel in the focuser to still bring eye pieces to focus for visual use!

[Gina]

Thanks for your reply Mark Moving the primary mirror seems a bit drastic and I don't think there would be enough adjustment, looking at it. However, I've got a book on "Digital SLR Astrophotography" and they suggest a Barlow lens which I have. Result - with T-adapter fitted to Barlow, camera focussed fine Of course a Barlow is a diverging lens.

Then I tried to take a photo - WHOA!! Camera refused to take a photo without a known lens attached!!!! What now?! OK... read the book, see if they cover that. Must be an answer - SLRs are supposed to be able to take any lens or adapter - surely that's the idea??? I have the Sony alpha DSLR-A200 Digital Field Guide too, which I haven't read right through yet. The answer could be in there.

This is a lot more involved than I suspected! DSLR seemed a good idea for astrophotography but I'm beginning to wonder. I still want a DSLR for traditional photography so that's alright. And I've ordered a Sony 75-300mm telephoto zoom which should be alright. But I'll think twice about buying a 3rd party Sony/Minolta A mount lens - they'll fit but will they work, I wonder! Maybe I'd be better pursuing the webcam/CCTV sensor approach. I have several CCDs and a CMOS sensor to use, including the Philips Vesta PCVC675K webcam that can be modified for long exposures. (Only 640x480 pixels though.)

I'm beginning to think I shouldn't buy anything over say £20 without being 101% sure it'll work with what I've got. Seems to be a bit of a minefield!

[mcrossley]

Oh dear, I know you can EOS T2 adapters with a chip in them that fools the body into thinking there is a lens attached. They still work without, but the auto exposure is disabled without the chip. Sounds like the Sony is a bit picky, I know the Canons and Nikons work OK without a lens.

[Gina]

Oh dear, I know you can EOS T2 adapters with a chip in them that fools the body into thinking there is a lens attached. They still work without, but the auto exposure is disabled without the chip. Sounds like the Sony is a bit picky, I know the Canons and Nikons work OK without a lens.

Looks like you're right! I know the auto functions wouldn't work without the right lens but I expected to be able to use manual focus, aperture and shutter.

The DSLR Astrophotography book I've got only covers Canon and Nikon cameras. The Sony A200 book only covers particular lenses and nothing on using other lenses, older film SLR lenses with adapters or any sort of adapter that goes between camera body and lens that isn't Sony and then they say only certain combinations of adapter and lens work, even if all are Sony.

After I'd bought the second hand Sony, I had a tax refund of over a grand and could then have afforded a Canon camera! Now, having bought the Sony plus extras for it I don't feel very inclined to buy yet another DSLR.

These Sony alpha series cameras have been out for quite some time and I'm wondering is some enterprising company has produced a similar camera fooling adapter for the Sony as for the EOS. Must do a google I think. Guess I should join a photography bulletin board too. I've evidently lagged a long way behind the times

[Gina]

I've found one on eBay - http://cgi.ebay.co.uk/AF-Confirm-Adapte ... 53e137aeea

I'll have to return the dummy I got from Amazon, for a refund.

[Gina]

I've found the answer! The camera has to be set to full Manual mode and then it will allow photos to be taken.

No chance of astrophotography lately but I did try it with terrestrial views. We live on the side of a hill and can see several miles across the valley when it's not too misty. Here is a photo of houses in a village well over a mile away. Light was poor and there was some mist (it's no better today). Shutter 1/60 and ISO 400. 10sec self-timer used to allow telescope time to stop shaking. Image size reduced by 4x for posting.

Rawridge.JPG

Equipment details :-
Telescope - Celestron Astromaster 130 EQ (MD ) - 130mm aperture Newtonian reflector - 650mm focal length
Barlow lens - Celestron Omni x2 giving a total focal length of 1300mm and f10
T-adapter and Sony T-ring
Camera - Sony A200K