Jewel Box - attempt 364

[PKay]

Well maybe not that many attempts, but I have found this target impossibly difficult.

This image is a result of 100 2sec subs.
Gain way down to 50 (139 = unity).

Carefully stretched and heavy on the saturation.

85mm refractor.

[raymo]

Peter, I know nothing about your methods or camera etc: but The Jewel Box
and the Gem Cluster are two very similar objects that respond well to a darkish background; makes them stand out better, and a neutral sky background colour is essential. I notice your image has an overall blue cast, which makes the image look a little garish.It also seems to be very noisy, did you use an uncooled camera and have a high ambient temperature at the time of capture? I have attached a pic of the JB which has a darkish background as mentioned, and another of the Gem which I deliberately gave an inky black background to make it punchy.
You really need to start from a neutral colour background, and then saturate the colour to taste.
raymo

[jenchris]

Taken with qhy8l last year.
Through a 100ed saxon.

[PKay]

Raymo, Jen

I am so happy you guys kicked in.

It has been a struggle to get this one right.

Both of your images are very good.

I can see amazing detail in this field, but how do we capture it?

There is blue, red, yellow, green and everything in between...

[billdan]

Hi Peter,

I never had any success imaging the jewel box, the resulting image never looks anywhere as good as it does looking through the eyepiece.
Through the eyepiece the jewel box really sparkles and does look like jewels.

Cheers
Bill

[doppler]

I think the hardest thing is getting the exposure right, the stars are getting over exposed because of their inherent brightness and loosing their colour. I have noticed on out of focus stars their colour is more prominent as the light is spread out and not concentrated in a point. Maybe putting an aperture cap on the scope to increase the f ratio (reduce the intensity of the stars at the scope) would work better than reducing the iso and shutter speed on the camera.
A couple of pics, the fist two are with an f15 mack (mimosa aka beta crucis and adjacent red carbon star) and one of the jewelbox a couple of nights ago with the 10" f4.8 .

[Amaranthus]

Ideally you should capture these bright clusters using R, G, B only (no luminance); but if you have a OSC camera, that’s not an option. Peter, why not turn the gain right down to 0? (HDR)

[jenchris]

I used fairly short exposures with the gain at 45 on the one shot colour ccd.
I tried not to overfill the cells. But I did have quite a few subs.
The colour of the stats came through but the actual stars are clunky and a bit unfocussed. I think my house which I was shooting over was a bit warm causing tur ule ce.

[raymo]

Peter, there is no colour in this field outside of the star colours; I'm guessing
that the colours that you are seeing are noise, if you look at Rick's version
you will see that the sky background is almost colour free.
raymo

[speach]

That is very nice!