New Omega Nebula shot

tornado33 · #1 06-08-2005, 11:26 AM

Hi
Conditions were better then they have been for a long time in Newcastle, dry, slight breeze to keep fireplace smoke down and rather cold. Took advantage of it to get this.
http://www.users.on.net/~josiah/baad...teredsmall.jpg
2 x 17 mins ISO 800 with baader UHCS filter.
10 inch F5.6 newtonian, unmod. EOS 300D
Off axis, manually, hand dec control guided.
I did a DF immediately after the 2 shots of same length (17 mins ISO 800). Manually subtracted this from the 2 shots separetly using Photoshop CS, then stacked them in CS as well. Used Gradient Xterminator photoshop plugin (no flat field done), levels stretching then default setting on Noiseware to finish off, then downsized image to show here.
Doing a DF immediately after a set of images gives better result than doing one some hours later on at the end of the nights imaging, I find.
Scott

Robby · #2 06-08-2005, 11:35 AM

Hells Bells that's a good shot Scott...!!

Stunning!!
I really should try the longer exposures! I have never really gone longer than 4mins. But's that's mainly due to the high level of light pollution here.
Was this shot done from a drak site??
Top stuff mate.

Cheers

tornado33 · #3 06-08-2005, 11:46 AM

Thanks

Actually no it was done at my back yard at Wallsend, Newcastle, quite light pollouted. It was good when i took the pic though, I could actually JUST see the S.M.C., and could see a little more then just the brightest parts of the Milky Way.
A combo of the Nebula filter and longer exposures really makes the difference.
Scott

Robby · #4 06-08-2005, 11:49 AM

The filter could be the key, as it allows you to expose for longer!! I might have to look into them. I have never really though of using filters on my DS shots, but your result certainly gives me some food for thought... Always something new to learn. Thanks.

gaa_ian (Ian) · #5 06-08-2005, 11:49 AM

Great shot Scott

I liked it so much I have set it as my wallpaper on my laptop
A shot worthy of submission to the Mag's I would think

Robby · #6 06-08-2005, 11:50 AM

PS.. How do you fit the filter to you setup? Is it 2" or 1.25", or something else?

Robby · #7 06-08-2005, 12:04 PM

Hi Scott,
What other filters do you use for astro-photography? Considering that your sky pollution sounds similar to mine, do you have any suggestions for galaxy filters?
Cheers

tornado33 · #8 06-08-2005, 12:51 PM

Thanks.
I use a standard size 2 inch filter, it fits into my 2 inch to T thread adaptor (one end screws into my standard Canon EOS T adaptor, the other end is like the barrel of a 2 inch eyepiece and goes straight into my 2 inch focusser, theres also a standard 2 incg filter thread, so I can screw the filter into the 2 inch to T thread adaptor, then attach it and camera to the focusser. I have some older Lumicon Deep sky and O3 filters 1.25 inch, when I used those for imaging, I made a cardboard ring that was tight enough on the filter to hold it securely, and would press fit it into the T adaptor. Some vignetting resulted but wasnt too bad. No such vignetting with the 2 inch.
The Baader UHCS I use isnt suited well for galaxies, as its for emission nebulas that emit light at specific wavelengths, whereas galaxies emit broad spectrum light from their stars.
At the last Ice in Space night at Kulnura I got to use a CLS filter (by Astromink I think). It was a lot less severe in cutting off starlight and showed the reflection nebula of the Triffid well, Im thinking that may be of benefit for galaxies. The old Lumicon Deep Sky filter may be as well. Also the Baader Skyglow filter http://www.baader-planetarium.de/dow...eodymium_e.pdf
This looks like it may work quite well for galaxies due to low light loss involved.
Sadly if all councils used Low Pressure Sodium streetlights, light pollution wouldnt be a problem as the 2 yellow emission lines are effectively blocked by most nebula filters, rendering what would be a pitch black sky through them.
Clear skies.
Scott