M27 - Tal2

[brendant]

Had a wonderful clear night last Monday night, great for imaging, took 10 x 120sec images of M27 but cannot get them to stack, just takes so long in DSS that I gave up.

Below single 120sec image with the 6" Newt and 400D, it has come out not bad for such a short exposure.

Brendan

[gary1968]

Very good Brendan, nice colours and great detail.

Gary

[lunator]

Brendan

for a single image that is very good

Cheers

Ian

[steppenwolf]

Like it - good image, Brendan, some great colour too.

[rawhead]

Stacks of detail. Great shot

Was the Tal mounted on the EQ5?

Cheers

Jon

[brendant]

Jon, yes Tal was on EQ5, have managed 3min ungided subs when I can get a good polar alignment, normally go for 2min subs.

Brendan

[RobH]

Great detail and colour. The Ha is showing through very well.

Cheers

Rob

[rawhead]

Do you ever image with the GEM mount Brendan? If so, what's the max sub time you've managed?

[SteelRat]

Nice single shot Dumbbell that Brendan 8) Good to see stuff from the T2

[Whippy]

For two mins that's nice . Good one!

Tony..

[brendant]

Thanks again guys for the feedback.

Rawhead - Yes I do image with the GEM (EQ5) and the Tal2 at prime focus and with eyepiece projection with a Hyperion eyepiece. With a good polar alignment and no wind, 3 Min's is possible with a stretch but 2 Min's is more realistic and yields a higher percentage of good subs. The Tal2 is quite heavy and pushes the EQ5 hard - a HEQ5 would be more ideal. I have no means of autoguiding so all my images are unguided.

I am attaching a stacked 14 min (6x 120sec 2x 60sec) image from the same session that the single sub above was captured, reset the star detection threshold in DSS and the images stacked no problem.

As an aside - how do you edit your original posts, I cannot seem to find the edit button, am I missing something or has the option changed.

Brendan

[Psychobilly]

Nice images Brendan both the single 2 minute and the Stack.

Have you used bias frames? There soem horzontal banding in the image which it would probably knock back.. Another great way of getting rid of it (if you have some of the PS family software) is to use the Horizontal noise reduction action in Noel Carbonis excellent Astro Actions...

I use DSS then Noel's tools and GradientXTerminator to process images

I have found a solution to DSS being slow... A quad core processor and 4 GB of ram ... last run I did on a NA Nebula image produced nearly 3GB of temp files...

Billy...

P.S. whats forum "ettiquette" on tweaking other peoples images to show the effects off various thrid party software add-ons?

[brendant]

Hi Billy,

Do not see the horizontal banding on my machine, ran Noels Action but don't know if it made any difference.

I don't use bias frames, maybe I should, what is the correct way of taking them ??

There is no problem tweaking anyones image to demonstrate or enhance it. It is a great way to explain a technique or show how a particular piece of software can be used to improve a problem on an image. just do your stuff.

Brendan

[Psychobilly]

Bias Frames are taken at the shortest shutter speed you can achieve at any given ISO setting with the lens covered.

If you look carefully in the single exposure image you can see horizontal bands of faint red lines.

These should be knocked back using the horizontal band noise reuction action in Noels tools..

Here's a quick play with the jpeg you posted ...

(click to enlarge)

Billy...

[Psychobilly]

Bias Frames are taken at the shortest shutter speed you can achieve at any given ISO setting with the lens covered.

If you look carefully in the single exposure image you can see horizontal bands of faint red lines.

These should be knocked back using the horizontal band noise reuction action in Noels tools..

Here's a quick play with the single frame jpeg you originally posted ...

(click to enlarge)

Billy...

[brendant]

Billy, see what you mean in the single image, certainly your version has improved things, thanks for the advice.

Brendan

[Psychobilly]

No Problem..

Thanks for letting me "tweak" your image...

Also noticed soemthing else today...

If you have the photoshop CS3 and shoot in raws then its possible to have a marked effect on vignetting by working on the raw image in the lens tab of Camera Raw 4.5...

Before importing into CS itself and best of all its non destructive...doesn't effect the original data

Billy...

[brendant]

All the images were actually captured as JPEG's, forgot to switch to RAW mode and don't have CS3, use Elements with the various plug-ins (Noels tools, Smartcurve etc...) for processing. With the DSLR vignetting is always going to be a problem on both scopes ED80 and the TAL-2, must start taking flats.

Brendan

[Psychobilly]

I'm working on something to make flats easier at the moment

It's early days but exploiting my contacts in the optics and light source field ... there are some interesting materials and sources becoming available....

My background is medical lasers and intense pulsed light devices (R&D)...and more recently custom LED's

Billy...

[rawhead]

As an aside - how do you edit your original posts, I cannot seem to find the edit button, am I missing something or has the option changed.

Brendan

I think the mods have restricted the ability to change posts. Seems to be patchy though? Click the modify icon top right (if it's there...)