Starry starry night...

[nytecam]

Great clear, calm and frosty last night in the suburbs for deepsky picture taking via my wide cam lens [Orion neb m42] and longer lens [350mm f5 fl = similar to what birders use] on some neaby galaxies in/near the Great Bear [Ursa Major] eg M81 @ 12 million lightyears [MLY] range and M51 Whirlpool Galaxy at double that distance or 23MLY range which means the light took 23 million years crossing space to arrive at my cam Exposure range from 20sec for M42 to 10min for the faint distant galaxies.

The Orion neb is a local minnow by comparison only 1300LYs by 24LY across. Hope pics of interest

[snowdrop]

Fab pics nytecam. Thanks.

Hard frost overnight here, (I hope had you woolies on), at 3am the moon was perfect providing me with an interesting hour or so studying the craters.

[Tringa]

Great photos, Nytecam, especially M51, which I feel is one of the most photogenic stellar objects.

You mentioned "my wide cam lens". Is this a particular lens or did you piggy back a "normal" camera on your astro set up?

Dave

[nytecam]

Originally Posted by Tringa

Great photos, Nytecam, especially M51, which I feel is one of the most photogenic stellar objects. You mentioned "my wide cam lens". Is this a particular lens or did you piggy back a "normal" camera on your astro set up? Dave

Hi Dave - thanks for your interest. I don't use film or DSLR cams for night stuff but a 'normal lens' [old Russian 85mm fl f/2 Jupiter] coupled to a Starlight Xpress 'Lodestar' monochrome CCD camera.

This unfiltered camera [eg no Bayer RGB or IR block filters] is >x4 'faster' than a regular colour camera and this equates to shorter exposures to record fainter stars in a given exposure - typically in the 20s - 100s max before my bright suburban sky [light pollution] completely washes out the picture.

To go 'deeper' I take a series of images of the same object exposed just short of the sky saturation point and later remove the bright sky background via camera software and 'stack' the images together - the galaxy pic taken this way eg 3 stacked 200s exposures = 600s = 10min total exposure. The 200s exposure broken down in 10x20s 'sub' exposures 'in camera' to minimise telescope tracking errors to keep the stars pin sharp.

Below a raw 60s exposure of dark Horsehead Nebula B33 beneath Orion Belt stars and with sky background removed - taken via wide angle lens covering 4 x 3 degree chunk of sky.

[Rexer]

Amazing pics nytecam as a beginner looking at your shots always gives me more motivation and information

[nytecam]

Thanks Snowdrop, Dave and Rexer for your interest Last night was even colder so didn't stay out too long but got a shot of my favourite 'distant' object eg a quasar in Lynx the Cat - a faint constellation above Gemini the Twins.

The quasar is so distant that galaxies between us and the quasar bend its light gravitationally and boost its light x20 so as to be much brighter than 'normal'. It's still exceptionally faint at magnitude 15.5 but pic just shows fainter nearby stars down to ~mag 16.

Now the awesome bit - the quasar is 12,000,000,000 light years [12BLY] away only some 1.6BLY away from the Universe creation 13.6B years ago.

If you prefer Km then multiple 12,000,000,000 x 300,000 [velocity of light per second] x 86,400 [sec in day] x 365 [days in year] to get the BIG number

[posie]

No, light year measurements will do Super pics Nytecam, I do not know anything about the subject, but do appreciate the pics, and the numbers/maths fascinate me, and I think the almost 'unbelieveability' of it all ,it's absolutely mind-blowing, so thanks for the info on the thread, and the pics...Posie..

[artdemole]

must have a look at Wonders of The Solar System bbc2 9.00 this evening..

[foxy mars]

What is a light year.

[posie]

As Nytecam explained above....
It is the distance that light can travel in a year. In other words it is a linear measurement. Light travels at 300 km per second. so a light year presented in kms is 300kms x 86,400 (seconds in a day) x365 (days in a year) = 9,460,800,000 kms per year. (I think ).......Posie,,,