Night sky images?

[fractonimbus]

Lenses: also worth a look, and usually very good prices: http://www.surplusshed.com I have found them quick and very reliable.

DN

[mcrossley]

Thanks for the links 1.68 mm FL lens and a 0.003-lux B/W camera with 1/3 inch CCD sensor would give 90 degrees coverage by my calculation though not sure the usual calculation applies at very short focal lengths. If you get 140 degrees with 1.9 mm, it looks like my calcs are wrong

The 1.9mm on this page comes out at 132 deg diagonal on a 1/3" format camera according to them.

[Gina]

Thanks Mark

I'm seriously thinking in investing in a high sensitivity camera like the 0.003 lux one. I think that in itself would show quite a lot. My MS Lifecam picks up distant street lights a good mile or so away and I think if it were pointed up at the sky more it might pick up the brightest stars/planets. Here is an image from my current "weathercam" with brightness, contrast and gamma correction to bring the background noise up to the threshold of visibility. This is a single frame captured with Yawcam, uploaded to my web site by my P4 XP machine and downloaded with my AMD 64 with Firefox in Linux. (Should add - it has a polarising filter, so that cuts the light by half)

webcam-night2.jpg

[fractonimbus]

Gina, what model Lifecam are you using?

DN

[Gina]

Gina, what model Lifecam are you using?

Microsoft H5D-00003 Lifecam Cinema Webcam to give it's full title.

[Gina]

The 1.9mm on this page comes out at 132 deg diagonal on a 1/3" format camera according to them.

I've just checked the CCTV cameras we use for security and checking the livestock. The wide angle lenses are 2.1mm focal length, used with "board cameras" - 1/4" CMOS image sensor. This gives something like 90 degrees coverage in practice. Both cameras and lenses were bought from Maplin but they don't do them any more. Pity I didn't buy more wide angle lenses when they were available really - cheaper than I've found elsewhere (but I tend not to buy more than needed).

[hans]

you can also let the (web)cam piggybak on a small telescope with goto-system.
eg the MEADE etx-70 isn't very expensive second hand.
so it would follow the earth rotation and allows longer exposures,without turning the stars into lines.
mods and info: http://www.weasner.com/etx/menu.html
done this a few years ago with a Philips pcvc840k (ToUcam proII)

[LeoLion]

You may find this Danish website of interest http://stjerneskud.info/fireball/webcam.html . The board camera used can be purchased from RF Concepts in Ireland . His initial lens was sourced from Edmund Optics but I believe he has now moved on to a Sunex unit . A web search will pull that one up. The lenses he is using are , I believe threaded M12 ( the fairly standard webcam lens thread http://www.optics-online.com/dsl_fisheye.asp . Hope this is a help

[fractonimbus]

You may find this Danish website of interest ...

Thanks. Very interesting indeed.

DN

[Gina]

This camera looks interesting :- http://www.dinodirect.com/1-3-SONY-B-W- ... y-GBP.html 1/3" Sony Super HAD 0.001 lux CCD sensor. Seems to come with an F1.2 3.6mm FL lens C/CS mount - could be swapped for a fish-eye lens. They have a half price offer on ATM - just 2 days left.

They seem a bit confused about B/W or "color" - a colour camera with a B/W image sensor

[fractonimbus]

Does look interesting but its minimum exposure would need hacking. Also says it doesn't like looking at the Sun

[Gina]

Does look interesting but its minimum exposure would need hacking. Also says it doesn't like looking at the Sun

I don't think any Sony HAD low-lux sensor would like the sun shining directly on it. An image of the sun produces a lot of heat. There is another dome camera, slightly cheaper, which quotes 0.01 lux sensitivity with the same aperture lens. This has the 1/3inch SONY Exview HAD CCD which I think was the one someone modified for long exposure. Link here :- http://www.dinodirect.com/1-3-SONY-Exvi ... P&AFFID=51. I have one of these on order (I hadn't found the Super HAD camera then).

[fractonimbus]

I have one of these on order (I hadn't found the Super HAD camera then).

Another gadget freak Someone after my own heart. I think this forum could be dangerous to my bank balance

I presume you need some sort of frame grabber to acquire the still image (presuming that's what you're after?)

DN

[fractonimbus]

I'm going to find out what sort of camera they're using at the HAT site at Siding Spring. See http://150.203.153.131/~hatuser/wth/cam_d.html The upper image is from a camera that works in colour during the day and B&W at night, but in the near full moon light (now, ~12:00 UT) it looks as bright as day. At times of dark of moon, you can see the brighter stars and the silhouettes of the small telescope enclosures very easily. Obviously has a huge dynamic range.

Really nice animation that shows this at http://www.mso.anu.edu.au/misc/hat/index.php

DN

[Gina]

Another gadget freak Someone after my own heart. I think this forum could be dangerous to my bank balance

Could be

I presume you need some sort of frame grabber to acquire the still image (presuming that's what you're after?)

Yes, you need a TV input device and software. Most will work with XawTV for Unix/Linux systems as well as having their own Windows software.