Pillars of Creation

[peter_4059]

Last night was unusually good up here. Here's 60x2mins using the DSI II through the Newt. The guiding is still playing up but apart from the eggy stars I'm quite pleased with this image.

Comments welcomed

[Bassnut]

Nice one Peter, smooth image for the exposure times, and nice detail.

Eggy stars are easy to fix ;).

[peter_4059]

Thanks Fred - what did you use to fix up the stars?

[Bassnut]

In PS, resize the image size times 4 (well, possibly less if the original was larger, say 2) to allow finer control.

Then Control A (to select it), contol C to (to copy it), contol V (to paste it). Now you have 2 layers of the same image. Set the upper layer to "darken" blend mode, then make sure the upper layer is active, and click on the "move" tool. Then click on the image again and use the arrow keypad keys to move the top layer left/right/up/down to make round stars. When smick, click on "layers" tab and merge, to get back to one corrected image. Then make "image size" back down to the original size.

This only works if there is slight egging, too much moving will induce artifacts.

[troypiggo]

Ripper one mate. Great detail and focus.

[peter_4059]

Thanks Troy and thanks for the PS tip Fred.

[multiweb]

Great pic Peter. Real nice details! :thumbsup:

[Dennis]

A stunning image Peter; great image scale and a large field too – well done! I hear ya about the elongated stars – I’m still ironing out my set up too!

Cheers

Dennis

[Peter Ward]

Interesting...but I'd strongly suggest getting the data capture right in the first place ;)

[Bassnut]

Yeah right, duh. Its an emergency fiddle :P:D

[jjjnettie]

That is beautiful Peter.
Lovely work.

Have you tried the Star Rounder plugin for Photo Shop and Paint Shop?
Works a treat, so long as you don't overdo it.

[Gama]

Good deal of data from the DSI II, come up prety good regardless of tracking issues.

Theo.

[peter_4059]

Thanks for the words of encouragement and tips.

I've been working on improving the guiding so I can have longer subs and don't need to correct the imperfections in post processing as per Peter's recommendation.

I spent some time on the weekend improving the balance in both RA and Dec however this seems to have made my guiding worse - especially in RA where I can see the guiding rocking back and forward. Last night I deliberately imbalanced the rig a bit in RA but not quite back to how it was but it still wasn't enough I guess. Are there any guidelines on how much imbalance I need or how to measure this apart from trial and error?

I've also encountered some issues in DEC where I've had to increase the guiding (rate?) from 0.3 to 0.6 in EQMOD to get Guidemaster to complete the calibration - it was complaining there wasn't enough movement in the star during calibration. I'm guessing this is a backlash issue however this seems to have got worse (since I changed the balance) for some reason. I'm wondering if something has become loose within the gear train? Is there a way to measure backlash in DEC - I know Guidemaster reports if it detects backlash but doesn't really quantify it. I assume the fix is to adjust the gear mesh?

I've also failed to get rid of my flexure issue despite removing my long collimation bolts. Anyone have any tips on how to track this down? I suspect it might be in the guidescope focuser - guess I could switch to the ED80 as guidescope and see if it improves.

Apart from these minor issues things are going well. I'm hoping for some help at Astrofest to resolve all these issues if anyone has any ideas.

Peter

[Tamtarn]

Nice and sharp with a good amount of detail Peter.

We are using a DSI PRO as a guide camera and have found that when the scope is in certain positions the screws on the focuser seem to back off slightly. Am looking at making a bracket in order to bolt down the camera to a sturdy part of the mount. Fred ( Bassnut) did advise he had done this some time back.

David

[peter_4059]

Thanks David. I think I've got the DSI mounted pretty firmly - changed to three locking screws on the focuser already although there is some weight in the camera and filter wheel so I should have a look at that.

[jase]

Great image scale Peter. Very nice. Once you get your set up tuned so you obtain round stars, the results will be awesome. Data could do with a little more stretching IMO, but its all there with good details present. Looking forward to seeing more. Well done.

[Ric]

A great image Peter, you have really captured some lovely detail in the pillars.

A fine job.

[peter_4059]

Cheers Jase and Ric. I'm quite please with how the longer subs turned out but the guiding errors and flexure are really driving me nuts. I wish there was an easy way to eliminate some of the variables. I'm toying with getting the mount overhauled next week in time for Astrofest.

[strongmanmike]

Man Fred, you the egg patrol or something?:scared: Not much difference if you ask me..? :shrug:...:screwy:? :rofl:

That's a nice image Peter and some great detail, well done :thumbsup:

Mike

[peter_4059]

Thanks Mike

[RobF]

I find I have to increase my pulse guide rate up to between 0.4 to 0.6 to keep Guidemaster happy too Peter. I seem to be able to get consistently get much nicer stars out of GM though, even though it says I've got quite a bit of DEC backlash. One day I'll work up enough guts to dig around in there....:whistle:

Fantastic pic! Have enjoyed seeing what's coming out of that newt lately.

[Hagar]

Well captured Peter, The detail you have managed to capture with the DSI is outstanding. Again you have nailled the focusextremely well. I wish I could do half as well.

Keep at it Mate.

[peter_4059]

Interesting that you've encountered a similar guiding issue Rob. I can't understand why it's become an issue after so long? I agree with you re GM - I seem to get a better result from it too however I get the same message re dec backlash - perhaps everyone gets this message - might be worth a poll as it might just be a bug.

Doug - the focus is easy given I have a very basic setup - my secret is
Orion motor focuser fitted to a GSO Crayford
Shoestring FCUSB
FocusPal software
Bahtinov mask

I overlay Magnifier software over the DSI live view with exposure set at 0.5 secs and focus on a bright star.

Peter

[RobF]

I'm pretty sure I do have backlash - can see it takes a while for the mount to reverse in DEC when I have the slew rate turned right down to absoute min in EQMOD (gets lower than hand paddle).

What's the Magnifier software Peter? Sounds like a clever addition to the focusing routine.

[peter_4059]

Rob,

Here's a link:

http://www.iconico.com/magnifier/

Enjoy.

Peter

[Rastas]

Peter
You have to have egg'y stars in that photo. It is the Eagle nebula afterall.

[Prickly]

Absolute ripper Peter.

What focal length are you guiding at? I wonder whether adding a barlow/OCR would help with the stars. Usually I guide with the C90 at 1m focal length and the stars are pretty sharp with the imaging at 800mm.

Have heard it said you should guide at 2x your focal length, in the days when it was all done by hand. Mind you, ccds are a lot better at correcting than the human eye so maybe it wouldnt make a lot of difference.

Cheers
David

[peter_4059]

Thanks David. I'm imaging at 1250 mm and guiding at 500 mm. I've also heard the 2x rule but thought the CCD guiding system was capable of sub-pixel accuracy such that this wasn't an issue.

After reading another thread on guiding I'm wondering if my guide star wasn't bright enough for accurate centroid determination. I've been using the star brightness chart in Guidemaster to adjust the number of stacked frames to ensure the chart doesn't max out. There is no reference to the chart in the instructions but I guess it is possible that it needs to be at the top of the chart to be bright enough.

Peter.

[Prickly]

Brighter guide star is well worth a try Peter. I know for a fact that balance issues caused eggy stars for me in my second last image - might be worth checking the balance of the scope in various positions too just to make sure, although I think you mentioned this was ok.

Like Jase said - there is more detail in your image if you stretch it. Also I regularly do an artificial darkframe in Pixinsight LE which helps too. Pixinsight is great for stretching because you can zoom in to 10x (more if needed) with the histogram to make sure you are not clipping it.

Im really amazed with this image how sharp the stars are. It would have me thinking twice about an RC scope. Can see Im going to need one of these GSO 10 inches.

Cheers
David

[RobF]

Thanks for this link Peter.
Have had my first opportunity to play tonight, and certainly a nice help with Bhat mask and Liveview on the canon.

Rob