Hi everyone, I haven't done any imaging in quite some time. Life seems to find ways of getting in the way of our hobbies. I am coming into a period of having some spare time, (hopefully), so was looking around for a new astrophotography scope to add to my set up. I was looking at the GSO 8" f/4, but found this skywatcher locally, and the build quality is much better. I have only just managed to process this photo, (still 4 others to do yet), and thought I would post it for comment and hopefully some C&C so that I can get better. My processing skills have a long way to go, which I think is evident in the photo but that's part of the fun, and as they say practice makes perfect. Hope you guys like it and thanks for looking.
On a side note there seems to be double diffraction spikes in this image, not sure if it's a focus issue, (hadn't made a baht mask at this stage), or maybe collimation. I collimated with my chesire that I have been using for years on my f/5 dob, but I realise that f/4 is a whole new game. I will order a Cats eye in the next month or so, but until then if someone has any ideas about what's causing it would be great to hear. Any tips on processing would also be welcome.
Image details:
Object: M42 Orion Nebula and NGC1977 Running Man
Location: North of Townsville NQLD
Camera: Unmodded Canon 1100D Astronomic CLS-CCD clip filter
Scope: Newly aquired carbon fibre Skywatcher 8" f/4 astrograph, MPCC
Exposure: Combination of 10 x 300sec & 10 x 60sec @ ISO800
Guiding: QHY5 4" f/5 newt and PHD
Stacked in DSS and processed in Photoshop CS2
I did a reprocess of this as I felt I way over-smoothed the original. I also incorporated Carl's suggestion when combining. I really liked the saturation of the second but lost some of the extended nebulosity so I also did a combine of the original and the reprocessed image which hopefully captured the best of both. Let me know which you prefer, and please tell me if you see something wrong as I really don't know what I am doing, and I am hoping to improve. thanks for looking.
Last edited by Rex; 20-10-2013 at 01:28 PM.
Reason: Added reprocessed pics
Congrats on the new setup!
You won't regret the 8" f/4, they are a powerful tool in AP.
Most of the double diffraction spikes is from slight twisting in the veins.
You can straighten them out easily with your fingers, slight pressure is all that's needed.
It's usually easy to see which are twisted just by eye.
Other double diffraction spikes can be from very close doubles.
Nice image, keep up the good work. Good job on preserving the core (not that out of practice), don't forget to blend the colour of the core image to back ground image so it does not look as washed out.
Mine are usually all little more purple than the main image with my modded camera so I have to take a little saturation out, you may have to add a little to bring a little more colour to it before flattening the layers.
Congrats on the new setup!
You won't regret the 8" f/4, they are a powerful tool in AP.
Most of the double diffraction spikes is from slight twisting in the veins.
You can straighten them out easily with your fingers, slight pressure is all that's needed.
It's usually easy to see which are twisted just by eye.
Other double diffraction spikes can be from very close doubles.
Cheers,
Justin.
Thanks Justin. It will be a learning curve with the new rig for sure, but I am pretty happy with the outcome for a first light. Thanks for the tip about the spider veins. I will check it out and hopefully fix it.
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Nice image, silky smooth looking.
Thanks Chris, my processing skills were never really up to scratch and its been a while so to be honest, I wasn't sure if the smoothness was good or bad. I figured the only way to get better was to post it and get some pointers.
Quote:
Nice image, keep up the good work. Good job on preserving the core (not that out of practice), don't forget to blend the colour of the core image to back ground image so it does not look as washed out.
Mine are usually all little more purple than the main image with my modded camera so I have to take a little saturation out, you may have to add a little to bring a little more colour to it before flattening the layers.
Thanks Carl. I will try what you have suggested. This is the first time I have tried to blend different exposures so any help is appreciated.
A twisted vane will just make a fairly thick vane optically - thus increasing the density of the spikes. Vanes that meet at the optical axis are closely double - the only 4 vane spider that will produce single spikes join as pairs on opposite sides of the spider hub which is a much stronger design anyway.
A twisted vane will just make a fairly thick vane optically - thus increasing the density of the spikes. Vanes that meet at the optical axis are closely double - the only 4 vane spider that will produce single spikes join as pairs on opposite sides of the spider hub which is a much stronger design anyway.
Thanks for the insite Mark. I had never noticed double spikes before so was wondering what the cause was. Not being 100% confident that collimation was spot on also put doubts in my mind I guess. Good to know its nothing to worry about. I will try to adjust things so as not to get them if I can coz I am not sure that I like them.
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Nice image. I like the subtle colours.
I kinda like the double diffraction spikes too, but you only see them when zoomed in.
Must be pretty warm in Townsville, any idea of the temperature when you were imaging?
Thanks Tel, yes its very warm. Had a lot of noise in the image which took a bit of cleaning up. I just had a look at the raws and exif temp ranged from 30degrees when I started and the lowest was 26 for this run. Need to cool my camera lol. Just another thing to add to the list. I wonder if I will ever have an empty list? Maybe if I ever win lotto.
That core is looking much like the main now certainly not washed out. Careful not to go to far I think the stars in the core have a slight ring around them. Learning how for to push is all part of the fun, you are doing great keep it going.
The third image wins my vote for the core as the second has more purple in it, but the second image is nicer on the main image for not over stretching. I agree taking away some of that smoothness has worked a treat.
I like the repro a lot. Saturated colors and details are very nice. re:diffraction spikes I find that the spikes will separate if the opposite vanes are not inline. I they are then they'll overlap perfectly.
Thanks Lewis. I will hopefully continue to improve.
Quote:
Originally Posted by carlstronomy
Rex,
That core is looking much like the main now certainly not washed out. Careful not to go to far I think the stars in the core have a slight ring around them. Learning how for to push is all part of the fun, you are doing great keep it going.
The third image wins my vote for the core as the second has more purple in it, but the second image is nicer on the main image for not over stretching. I agree taking away some of that smoothness has worked a treat.
Carl
Thanks Carl. I don't know what happened when I did the original. I think I got a little overexcited about the result and didn't know when to stop. Then when I looked at it after a couple of days, the plastic look hit me fair in the gob, and I knew I had stuffed it up. We live and learn.
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Originally Posted by 5ash
Hi Rex,
Love the reds in the second image , lovely detail .
Regards philip
Thanks Phillip. I was reasonably confident that the data was ok, my weakness is definitely my processing skills. Weather permitting hopefully I will be getting lots of practice in and I can only get better at it the more I do.
Quote:
Originally Posted by multiweb
I like the repro a lot. Saturated colors and details are very nice. re:diffraction spikes I find that the spikes will separate if the opposite vanes are not inline. I they are then they'll overlap perfectly.
Thanks Marc. I will have another look at the spider vanes, and see if the secondary is centre or not. Is it possible to have ok collimation when the secondary isn't central though? I'll check it out.
Quote:
Originally Posted by Meru
Very nice rex and I like the last one the most. Perhaps a bit more saturation? Your tracking and collimation looks great by the way!
Thanks Meru. As I said in my post I have no idea what I am doing lol. Just winging it and hoping for the best when it comes to processing. The capture side of things I'm much more confident with. Can I ask how you can tell by looking at a photo if the collimation is good? I've heard similar comments before about other members photo's on here, and I am not sure what to look for in a photo to tell.
Thanks Marc. I will have another look at the spider vanes, and see if the secondary is centre or not. Is it possible to have ok collimation when the secondary isn't central though? I'll check it out.
Yes you can. But if you get your vanes exactly square you'll get nice neat thin lines. But both ways work. I like mine tight but I've had plenty of shots in the past where I had 8 instead of 4. Just personal preference. No biggie.
Yes you can. But if you get your vanes exactly square you'll get nice neat thin lines. But both ways work. I like mine tight but I've had plenty of shots in the past where I had 8 instead of 4. Just personal preference. No biggie.
Thanks again for your insight Marc. I realise personal choice has a lot to do with how we portray our images, but on this one I'm with you. I like thin straight diffraction spikes. By the way your image at the link in your post is stunning. I modded my 1100D on the weekend so can't wait to try it out.
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Originally Posted by kosh
Beautiful images
Thanks Kosh.
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Originally Posted by rcheshire
Nice job Rex. Not that eas, so very well done.:thumbsup
re:diffraction spikes I find that the spikes will separate if the opposite vanes are not inline. I they are then they'll overlap perfectly.
