A couple of quick clusters

[cometcatcher (Kevin)]

Finished up my shooting session last night after the comet with a couple of southern open clusters as the moon was rising. NGC2516 in Carina and IC2391 in Vela, both near the false cross. Each have a different camera orientation, IC2391 with north up and NGC2516 with north left. Both with the same setup, IC2391 was 16 x 30 secs and NGC2516 23 x 30 seconds.

Common details: Bintel 8" F4 Newtonian, Baader UV/IR cut filter, Baader MPCC MKIII coma corrector, HEQ5 pro unguided, ISO3200, Pentax K-5. Stacked in DSS and processed in photoshop.

Bigger at Astrobin.

http://astrob.in/147062/0/

http://astrob.in/147069/0/

[raymo]

Very pretty Kevin, I bet your ED 100 is sulking in the cupboard.
raymo

[cometcatcher (Kevin)]

Originally Posted by raymo

I bet your ED 100 is sulking in the cupboard.
raymo

Heheh. You win bet. Actually it is better for luna and solar so that's it's job now.

[strongmanmike (Michael)]

They're great Kevin, nice work.

We don't see enough open clusters imaged.

Mike

[cometcatcher (Kevin)]

Thanks Mike. The ones with nebula in them are more popular I think, but the plain ones are good summer objects up here in the hot cloudy north. Don't have to strain so hard with them lol.

[Regulus (Trevor)]

Nice results Kevin and I particularly like the 2nd image (IC2391). A sparse and attractive little group of stars.
Well doe,

Trev

[LightningNZ (Cam)]

Two very pleasant and accurate renditions Kevin. I always enjoy open star cluster images, but they don't often get much love.

[cometcatcher (Kevin)]

Thanks Trevor and Cam. The sparse ones are like little constellations in their own right.

Here is what I have learned about imaging open clusters. It's nice if they stand out from the background stars. They look nicer with diffraction spikes than just blobs from a refractor (really liking my Newt). They look good with a bit of colour.

[raymo]

Spot on Kevin. My favourite pic of 4755 is a short exposure single frame
I took with hardly another star to be seen.
raymo

[LightningNZ (Cam)]

Originally Posted by cometcatcher

Thanks Trevor and Cam. The sparse ones are like little constellations in their own right.

Here is what I have learned about imaging open clusters. It's nice if they stand out from the background stars. They look nicer with diffraction spikes than just blobs from a refractor (really liking my Newt). They look good with a bit of colour.

The diffraction spikes and the secondary help to shift more light into the 2nd Airy ring, so this area gets enough light to show up clearly but not enough to burn out white. That's my take anyway and I'm sticking to it.

As Raymo just said too (in a way), very deep exposures drown out the brighter stars. Keeping that relationship closer to what you see through a telescope makes the clusters stand out and enhances the visual impact.

You and I must go after the Coathanger Cluster when it's back in the sky.

[cometcatcher (Kevin)]

Originally Posted by LightningNZ

You and I must go after the Coathanger Cluster when it's back in the sky.

Sounds like a plan. I haven't heard of that one before. I looked it up, looks nice.