March Comparison - Crux

[PKay]

After lots of debate and one vote, the constellation of Crux it is.

This thread is an opportunity to compare results from different equipment, techniques and most importantly experience.
And is a great way to learn.

Wide field will show IC2944 (Running Chicken), the ‘Coal Sack’ dark nebula, the Jewel box just to mention a few.

And for those with zoom zoom scopes, pick a spot (I want to shoot the chicken, yes I know it's across the fence).

Icearcher has already dived in (good one Chris) with a great wide field shot.
http://www.iceinspace.com.au/forum/attachment.php?attachmentid=224646

And remember to give as much capture information as you can.

Have fun!

[doppler]

If the weather ever clears here I'm in. Lot's of interesting stuff in this region. Here's a link for some ideas.
http://www.shoalhavenastronomers.asn.au/constellations/crux/

[raymo]

Here's a Jewel Box to get it started. 18x15secs ISO 400 8" f/5.

The other extreme. Single frame 8secs @ ISO800. Best viewed
around 50% screen magnification.
raymo

[PKay]

Good one Raymo

8" f/5: Lots of variety in the star colour and it is always interesting the way spider vane diffraction spikes separate into colours as well.

2nd image has not only brought out the yellow orange star that is so famous but also managed to separate its small orange 'companion'.

Short exposures & low gain rule on this one.

Just reading about the Jewel Box, from the Constellation guide: 'The dominant star in the cluster is Kappa Crucis (HD 111973), a red, M-type supergiant with a visual magnitude of 5.98'.

[rocco57au]

A quick take of the Pearl Cluster NGC 3766 - near the Running Chicken (just a tad across the fence Peter :P )

I was just playing around with some camera/mount settings on that night so not really focused on capturing more images.

A combination of LRGB 1 x 300 sec each. Stacked and processed in Photoshop minor levels and curves adjustment (my processing skills are not the best)

For some reason my images look much better in Photoshop before saving as jpegs. They lose a lot of detail... any suggestions? :shrug:

Rocky

[raymo]

Rocky, If your images need any sharpening, do it after you downsize the
image, not before. I find some images are more affected than others by
the downsizing, and have never tried to find out why.
raymo

[sil]

I'm of the opposite opinion to Raymo on sharpening. Best to try both for yourself and see what you think. Its common for people to oversharpen which introduces artifacts so i've always gone with sharpening before scaling down the image as for me it hides the artifacts and softens the aggressive areas giving the whole image a more consistent and even sharpness across the frame. This is based on my photography (not astrophotography) experience mind you. Experiment for yourself and your software.

Rocky, as for your images looking worse in photoshop after saving to jpeg thats because jpeg is a lossy compression system and in high contrast areas (like the blackness of space around each bright star) the artifact "blocks" are most common. The more you compress the worse the effect. Plus you may be working with 16bit images in photoshop but jpeg only supports 8bit so you lose data there too. I always make sure to convert to 8bit depth first to see how bad the degradation to colour/contrast is. Then maybe make a final adjustment to bring it back to what I wanted before saving to jpeg. The other "gotcha" people encounter is the colourspace. If you have a good colour calibrated monitor try to work in AdobeRGB then convert to sRGB before saving your final jpeg. Again you may need to make some adjusting once in srgb and make sure to select srgb as the colourspace for saving. This way your image has a good chance of looking the same for others when you post it online as it does to your eyes at home.

[rocco57au]

Thanks for the tips guys. I will play around with the suggestions given and see how I go :thanx:
I have been playing around with 16bit images before saving to jpeg, so that's one issue that can be addressed quite quickly and easily. Play around with other suggestions as time permits :juggle:
Still lots more to learn!

Rocky

[PKay]

My first go at the Cross.

Attached the Canon 550D piggyback onto the guided scope...not very well, it fell off :rolleyes:

30 of 60sec. ISO400
10darks, lights & bias

Canon 55-200mm zoom, f5.5. Adjusted zoom to frame.

[xelasnave]

It fell off!
That makes me sick in the stomach. ..it survived I presume.
The times I have nearly dropped the camera I often think to lay a rubber mat under the mout...in fact when I finish the cube observatory I think I will.
I had a focuser and the whole lot and camera fell out???
I caught it but oh that sinking feeling.
Anyways nice capture I can see various objects.
Alex

[PKay]

Thanks for your concern Alex.

It appears the lens was damaged as most of the stars are square :(

Anyway keeping on the theme of failures, I captured the jewel box wide field.

I forgot to release the focuser lock screw so the motor wasn't doing anything.

The result was out of focus and overexposed.

60 of 20 sec. gain = 25

On the upside, the EMU was in full view and absolutely spectacular.
And then the bright orange crescent moon rose over the ocean...

[PKay]

I finally shot the chicken, lots of blood.

And that's it from me, good luck everyone!

[xelasnave]

Great effort Peter.

I am back in Sydney.

I might be able to get the chicken if I set up the heq5 upagainst the balcony rails but even then, if that works, I dont think can get more than 15 minutes. But I will have a go at something tonight if only a random patch of sky to get at least some stars to play with...

I have lined up a spot up on the Hawksberry River< in the car park of the boat shed where I had my old boat, and although there is a big light there at least I can see most of the sky.

Alex

[Icearcher]

Hi All

Managed to get out last night for a few hours, I set up about an hour south in a forest so there was still some light pollution.

Still can not get polar alignment to be anything better than average, time to learn drift alignment. Can you drift align a SW star adventurer? Time to find out :)

Sony RX100m4 @70mm equiv
20 x 120sec
10 darks
stacked in DDS and edited in PS.

I might have overcooked the editing a bit but I managed to get some nice colouring in the nebular.

Regards
Chris

[PKay]

What a cracker!

Try counting all those stars...

You have captured the colours of the sth. cross well.
Gamma Crucis being a red giant (the orange one) and the blurry bit on it's edge is the white/blue companion.

Could you see the whole emu on the night?

Well done Chris.

[xelasnave]

Great effort.
I now have a little scope set up with an illuminated reticle to align, used for nothing else, rather than swapping stuff on the main scope so I would think a similar approach for your rig maybe ...a small scope with cross hair illuminated makes it easy if you have a open view of the sky...but there are ways and ways..I only drift align because I cant see the Celestial South Pole.. if I can see it I do the star trail line up.
Thanks for posting your efforts, I personally find, very encouraging as to what can be done.
alex

[xelasnave]

Looking at your capture I think you did a fair job with alignment.
alex

[ChrisV]

I wasn't sure what to go for in Crux, so why not a Dark Nebula. In the centre is one with the appealing name HMSTG-299+0.
In the left-top corner A-Crux.
Towards the upper/right is the open cluster NGC4349.

This is 40x 60sec subs at unity gain on ASI071pro, with 80mm F5.9 refractor; half moon on the weekend. The mount was an EQ5 that I've motorised by adding some belt driven stepper motors and building the onstep GOTO.
http://www.iceinspace.com.au/forum/showthread.php?t=133677

Really light and portable, and seems to work OK for unguided AP at short focal lengths. Should work better when I get higher resolution steppers and larger gear ratio.

[PKay]

Good one Chris.

Just the slight hint of blue in Acrux, shades of colour in the gazillion other stars. Excellent focus.
And the mount seems to work well.

Very clever!

PS: I have just come inside (10.15PM) after being told off by the neighbours. Was using an angle grinder to modify my now destroyed OAG :(

[ChrisV]

Neighbours - they just don't get it ...

[raymo]

My contribution. Acrux close up.
raymo

[PKay]

Superb shot Raymo.

About perfect I'd say.

Well done!

Capture details??

[ChrisV]

Nicely separated Raymo!

[raymo]

I have added Beta Crucis. Alpha was 8secs @50mm[heavily cropped]
ISO 3200 Canon 1100D. Beta was the same, but 6secs.
raymo

[PKay]

Well done Raymo

Amazing results for such short exposures.

Beta Crucis is a double separated by only 8AU.

I wonder if that second diffraction spike is from the double?

[raymo]

It could be, but if you magnify the Alpha image to about 200% you will see a
slight doubling of the spike. I think it was an artefact of my scope.
raymo

[PKay]

Hey Raymo

'Alpha-1 Crucis is also a spectroscopic double'.

Don't know what that means, but you get my drift.
Might not be an artefact...

[raymo]

A spectroscopic double is when the stars are too close together to be
separated optically, no matter how large the telescope is, and only a
spectroscope can detect such a double. Put simply, its all to do with the wavelength of light.
raymo

[PKay]

Maybe so...

However, nice to imagine that the variation in the spike, is indeed an optical separation of the two stars.

I think it is.

And you may be the first to have done it!!

[kosborn]

Hi all,

I'm new to IceInSpace and new to astrophotography (I have a Skywatcher Esprit 100ED that is only 6 weeks old). I thought the Crux theme was a good way to post a first image. I'm also new to PixInsight so I couldn't get the colours in the Jewel Box to be as bright as I'd like (although that could have been due to the brightness of the moon).

Cheers, Kevin

[xelasnave]

Welcome Kevin.
That is certainly a nice way to start with a very sharp image.
Well done and I hope you can share more in the future.
Alex

[xelasnave]

What camera and settings? Any darks flats etc?
Alex

[kosborn]

Thanks for the encouragement. I'm using an unmodified Canon EOS100D attached to a Skywatcher Esprit 100ED. This was 26x 60 second subs at 800 ISO with about 15 darks together with bias and flats. The camera works well on bright targets but not so well on dimmer targets. I've been trying to get the Horsehead nebula before it disappears over the horizon using 180s subs but have been slowed down by clouds, moon and even neighbourhood blackouts. I've accumulated about 40 subs but the images are still really noisy and I may not finish it until Orion comes back up in the east!

Kevin

[xelasnave]

Dont forget to give Eta Carina some attention☺
Alex

[PKay]

Very good Kevin.

Way better than my first image (mid last year).

You have great focus and there is plenty of good colour in the stars (not an easy thing to do).

Still there is an undending learning curve to climb.

Have fun along the way!

[ChrisV]

Really nice first go Kevin. I think you've got good star colour there and its nicely composed. As Alex says you might be better trying Eta Carina, much better location now. The horsehead is nearly gone (as least for me).

[kosborn]

Funny you should mention Eta Carina. I took this on the 14th March from about 60 subs and didn't post it because there were so many better posted recently and because the nova is just outside my field of view.

Kevin