observing from bed

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jeff.stevens
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Re: observing from bed

Post by jeff.stevens »

michael feist wrote: Sun Sep 27, 2020 7:31 am For more information about 'Astronomy and the Camera Obscura' by Mike Feist, yes me, refer to J.B.A.A 110, 1, 2000. This was also available on the Internet. I do have a copy if you are interested. maf.
I’ll see if I can find this on the Internet, Mike. Thanks for the info.
jeff.stevens
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Re: observing from bed

Post by jeff.stevens »

brian livesey wrote: Sun Sep 27, 2020 7:51 am Thanks Jeff for the concise Mobbereley biography of George, and showing those magnificent binoculars. He must have had a photographic memory, combined with the patience of Job.
His memory must have been incredible. I can’t imagine what it must be like to be that talented an observer. I think the book estimates how many star patterns he knew from memory, but I can’t remember the actual figure so I won’t make a guess. It seemed a staggering feat from my recollection. I’ll have to dig out my copy of the book.

Best wishes, Jeff.
David Frydman
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Re: observing from bed

Post by David Frydman »

George Alcock's large binocular was a Schneider 25x105 with 45 degree inclined eyepieces.
These had triplet, probably uncoated, objectives.

Unfortunately when these objectives were distributed to the U.K. the components got separated. They were bought by different dealers.
Some bright spark commercially sold 4 plus inch Newtonians made with one of the components aluminised.
These were of substandard performance as the were not made for this job, and were approx. spherical not parabolised.

Some of these 25x105 binoculars may also have been made by Zeiss and Emil Busch, or the bodies made by one maker and the optics by another.

I had several Zeiss survey cameras but made by Emil Busch with very high quality 75cm Zeiss Telikon, Zeiss 50cm Aero Tessar and Zeiss 20cm Topogon lenses.
These covered 30cm x 30cm film.
The cameras are enormously heavy despite light weight metal being used. A pressure or vacuum back.

George Alcock also used hand held binoculars, maybe 10x50 and Soviet 20x60 to make discoveries, some from indoors.

Regards,
David
brian livesey
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Re: observing from bed

Post by brian livesey »

Interesting stuff David. I'd forgotten that Alcock was as much a comet-hunter as a novae one. Incidently, he said that when he was North Africa in the army, the desert nights were not as good as the best ones from his home in East Anglia, despite not being far from the South Yorkshire industrial belt. He reckoned that the desert air had very fine sand particles in it and that made a difference.
brian
michael feist
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Re: observing from bed

Post by michael feist »

Jeff . The camera obscura in the film was a mock-up, we decided. Another TV mock-up camera obscura was used in Midsomer Murders when the victim was clubbed to death by a winding handle from the camera obscura set up on the village green for a fete. I assembled a long list of camera obscuras, that I came across in my researches, both historical and recent. From small drawing camera obscuras to large room camera obscuras. No doubt I could pull out a list of ones in your area but of course some may have ceased to operate, and of course none can open at present. mike.
jeff.stevens
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Re: observing from bed

Post by jeff.stevens »

That’s really interesting, Mike. Thanks for the info. Is your guide to the camera obscura available to buy? I’d be interested in reading more.

I’ve found articles on the Internet relating to you and your camera obscura knowledge, but I don’t think they are the full guide.

Best wishes, Jeff.
michael feist
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Re: observing from bed

Post by michael feist »

Jeff, Unfortunately once I retired all my detailed notes in were donated to the Local History Dept of Brighton Reference Library, which was later taken over by THE KEEP. This was when the Foredown Tower was stripped out, but leaving the camera obscura, when taken over. All that I have now is a single copy of a booklet that I wrote "Pocket Guide to Camera Obscuras of Britain and the World" issued by Hove Borough Council in 1995 and Tabulated "Reference List of Camera Obscuras of the World - Part and Present" [an updated list 2016] but really out of date. I will photocopy these and forward with a copy of them somehow to you. Modern technology is not my forte. regards mike
michael feist
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Re: observing from bed

Post by michael feist »

Jeff, did you find BAA article "Astronomy and the Camera Obscura'? That is in harvard.edu/abs page.mike.
jeff.stevens
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Re: observing from bed

Post by jeff.stevens »

Mike, that’s very kind of you to offer to photocopy it. I’m more than happy to cover the costs too. I’ll drop you a private message on here with my address and details.

I’ll have another look for the BAA article.

Best wishes, Jeff.
jeff.stevens
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Re: observing from bed

Post by jeff.stevens »

michael feist wrote: Mon Sep 28, 2020 12:03 pm Jeff, did you find BAA article "Astronomy and the Camera Obscura'? That is in harvard.edu/abs page.mike.
Just found the article, Mike.

http://adsabs.harvard.edu/full/2000JBAA..110...25F

Best wishes, Jeff.
michael feist
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Re: observing from bed

Post by michael feist »

Jeff
You may also like to go to see
www.foredowntowerastronomers.org.uk
Then open 'Archive'
There in you will find yet another article ' A Personal History of Astronomy at the Foredown Tower ' ....by me.
regards mike.
jeff.stevens
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Re: observing from bed

Post by jeff.stevens »

Thanks Mike, I’ll take a look.

Best wishes, Jeff.
Cliff
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Re: observing from bed

Post by Cliff »

re - visually observing & astro-photography through windows. I am inclined to think if done in a dark sky location it might not be too bad. Particularly if fairly square on to the window. However, the fun really starts if the locality is very light polluted.
Best of luck from Cliff
nigeljoslin
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Re: observing from bed

Post by nigeljoslin »

Had a spare twenty minutes yesterday evening and decided to observe low down Jupiter and Saturn. My only option in the time available was the 4 inch short-tube refractor through the landing window, pretty much a straight-on view through the glass.

It was nice to see the two planets again. The view at 58x was nice, but experiment proved that this was the highest usable magnification. Conclusion, the window introduces distortion.

But, better than nothing, as it brought me pleasure! :)

Best wishes, Nigel
Skywatcher 350P f4.65, Skywatcher StarTravel 102 f5, Adler Optik 9x63 binoculars
brian livesey
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Re: observing from bed

Post by brian livesey »

How's your 4-inch/f.5 refractor for chromatism Nigel? I have the same spec, but a Celestron. The chromatism is pretty strong on higher powers. I bought a Baader semi-apo filter to deal with it, but I reckon that it's only about 30 per cent effective. It also reduces some of the incoming light, in contrast to the much more expensive Parracor.
Chromatism doesn't matter much on point sources - stars -, but it's obtrusive on bright extended images like the moon and planets.
brian
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