Keyhole Nebula - C11 at f/10

[multiweb]

27x120s on a G11 with QHY8 on C11 at prime focus, autoguided with PHD and QHY5 with meade OAG adaptor and capture in Nebulosity 2. Stacked in CCD Stack and processed in PS3.

Took this last night before the moon rise to test all my "bits and pieces" on a C11 I have on loan. Imaging at that FL is a bit scary at first. Everything is magnified and seems to "jump" all over the place. Goto and finding objects is a bit of a challenge too. :P I'm used to image at 650mm FL maximum so that was a bit of a shock. The processing part is great though coz there are so many pixels in the stars to play with :)

Full frame at: http://www.multiweb.com.au/astro/eta_f10_f.jpg

Focus is soft. No mask yet so I eyeballed it :whistle:... and the camera is not exactly square either (see right of the frame) but the tracking is sorted out.

So overall I was happy with a pretty picture and having heard a few rumors about imaging with SCTs I can now see some real potential in the scope once working around a few things.

Hope you like it. :thumbsup:

[AlexN]

Focus looks good to me, collimation could do with some work though... it reminds me of my first C11 image where I thought focus was off, but inspected the collimation the following night and realised that it was out quite a bit...

Other than that, your guiding looks good, field of view is stunning! The OAG is the only way to go, otherwise you'll be struggling with mirror flop issues and all sorts of flexture problems.. I know I did! :D

Good work mate, Give that collimation a touch up and you'll be producing some fantastic work..

[AlexN]

Oh, the fickle finger is making a nice appearance too!

[multiweb]

Yep... must be the collimation stearing me in the face :lol:

[jase]

Geez Marc! You weren't kidding when you indicated you wanted to get into a little more longer focal length work. Grit your teeth and go for it. Alex has nailed the collimation issue. Can see that in the full frame, but I really admire the details you've obtained. A good sign of things to come when you get the rig dialled in. Well done.

[multiweb]

Thanks Jase. Yeah I'm doing a bit of reading and looking into locking this mirror into the "sweet spot".

[Quark]

Hi Marc,

Your rig definitely shows some potential ounce you sort out the collimation and maybe make a Bahatinov Mask.

Looking good
Regards
Trevor

[multiweb]

Yeah I need help on the focus side of things :lol: I bought Alex's Bathinov so it's shipping - until then be prepared for more horror shots :whistle:

[strongmanmike]

Well not bad at all Marc!

Nice everything, the collimation may be a problem, yes, but it's still very pleasing so imagine what it could look like with perfect colimation ;)

As far as focusing goes, can you zoom in on a star in the FOV and just focus manually on it on the screen? If so, that is all I have ever done, no masks, no focusing routines nothing...? I seem to nail the focus every time with this very boring method? :shrug:

Mike

[multiweb]

Thanks Mike... That's because you're a natural. After a couple of glass of wines I need BIG focusing knobs.

[Bassnut]

Nice Marc, welcome to decent FL imaging :thumbsup:.

Manual focusing Mike?, yep, its boring alright :P. Autofocus makes that time consuming stuff sooo twee :whistle:.

[AlexN]

Yeah Marc, I strongly recommend getting yourself a motorized crayford and getting some form of autofocus setup... Definitely the way to go... Focusing is SO much faster, not to mention, you click a button and wait for it to say its done...

[jase]

Hear! Hear!

(anything the maximises data acquisition time is a good thing)

[multiweb]

Actually I looked into focusmax a while ago but is it real worth it?:confuse3: I mean for remote imaging, yeah, you've got no choice but when you're next to the scope? Involving a program into the focus routine is another computer involved. :rolleyes: Another potential point of crash. I like to keep things simple. :shrug:

[multiweb]

Thanks Fred. Nah.... I tend to be old school with things like focusing. If I could do without a laptop on the field I'd gladly do so. I don't like to rely on too many programs. Only tracking and data acquisition for me. That's it. No more no less. Being in the IT industry I hate bloody computers and servers. :bashcomp: I do astrophoto for relaxation . I remember those two blokes in Crago one night pulling their hair over a Meade LX200 autofocus set-up for over two hours and I couldn't help thinking WTF!? :doh:

[strongmanmike]

LOL now we have a stoush over whether to manually focus (with a moto focus that is) or use an auto focus routine :lol:

I think in the end it comes down to what you have at hand I guess?

Having said that I do waste a bit of time sometimes going in and out juuuust in case the focus wasn't peeeeeerfect when I was about to start imaging, sometimes I do this a few times too :doh:....? I think I generally get pretty sharp images in the end though so I must be doing something right :P..ok price to pay for a few minutes less imaging time me thinks :whistle:

Mike

[Bassnut]

Oh, yeah, im with you there. If you can do without a lappy going mobile, then autofocus is a small sacrifice. I ment permanent. I have wasted whole nights fighting with a lappy in the field.

[spearo]

Looks good Mark,
I went straight to the full frame and looked at the Fickle Finger!
well done
I have a Event Horizon 10 to 1 motorised but now that I use a (home-made) Bahtinov mask, I focus it by hand not even using the motorised option)
keep up the great work
frank

[multiweb]

Thanks very much for the feedback and comment Frank. :thumbsup:
Yeah I love my Bathinovs too. I've got one in every size but not for the C11 yet.

[AlexN]

when i bought my focuser for the C11 I figured, the motor is only $100 extra, may as well... I used it with the hand controller for a while, then figured the FCUSB was only $70, so I got that... that did away with the hand controller which was nice, then Fred put me onto focusmax after my first use of CCDSoft's @focus... Now I wouldnt be without that setup..

[bluescope]

It seems this thread has turned into a debate about auto focusing so while we're on the topic what auto focuser would be good for a WO FLT110 ? Although I have to add that once I have got the focus set manually ... as long as I am careful ... the scope doesn't budge even with my dismounting and remounting etc.

Nice image btw Marc !

:thumbsup:

[AlexN]

Steve, I had a moonlite on my WO 102mm for the majority of the time I had it, it was good... If I had my time again I would have gone a feathertouch... Robofocus is apparently very good also... or step it right up and find some way to adapt TCF-S to it!! :D

[gregbradley]

Nice image there.

I haven't used autofocus yet but have used electronic focusers a few times.

Its more convenient than manual as I can stay at the computer to do it.

I use CCDsoft and its graph to determine when I have optimum focus.

I wonder if there is a weakness with autofocus as I have seen the graph method sometimes falter when it registers a bit of poor seeing as though focus was off. But that's only when your focus is really close.

Greg.

[Bassnut]

Greg

With focusmax, you just once run a calibrate routine that characterises your image train, after that, autofocus is insanely fast and always spot on, much better than possible visually. If the seeing is really bad, yes, it can give up. Then it just reverts to the previous setting.

[gregbradley]

Robofocus is really good and it only takes about 15 minutes to install. Really very easy. Extra motors to put on your other scopes aren't that expensive.

Greg.

[RB]

Marc that's a great image of the Keyhole, I love the image scale on this.
Well done mate !

Just curious, did you take flats on this?

[multiweb]

Thanks Andrew. The image scale is approx 0.5 arcsec per pixel.
Yes I did take darks and flats. They didn't work too good - well spotted :whistle:. My A4 EL sheet is too small to illuminate the whole aperture. I made it for my 5" newt so I'll have to upscale that too. :)

[multiweb]

Well I just got my NB filters delivered today after 4 weeks waiting and obviously the weather is not playing nice. :windy: I'm stuck indoors going through old data. After having a shot at processing M81 for fun and checking how sharp Jase's version was from the same data I had a quick chat with him :confuse3:and realised that I've been using the "wrong" alignment method with my subs :doh:. So I have A LOT of data that I've butchered over the past year or so :whistle: that I'm going to go back to. As big kev would say "I'm excited!" :)

Here's a first repro of the keyhole that shows much more details and better color balance than my first shot at it with the same source data.

The full field is here: http://www.multiweb.com.au/astro/eta_f10_nf.jpg [4.4MB]

I think it is noticeably better in details in the nebulosity. All I need now is clear skies :prey: and another go at it with a collimated scope this time.

[Bassnut]

Ive got them both side by side here, somethings gone wrong with the background on the repro Marc, I like the 1st one better, but I must say lots of detail on both, nice work.

[bloodhound31]

I think it's a beaut pic!

Love this one. Always a favorite. Good FOV and nice colours.

Baz.

[multiweb]

Thanks Baz. :thumbsup: Considering that was my first autoguided shot on the C11 meant as a test only from my backyard which suffers from heavy LP I was very surprised with the result. That's why I posted it. I would never have been able to image this with the 5" because of street lights/M7 sky glow and that's the reason I do only narrow bandfrom home. Now I know f/10 is much more forgiving with stray light, it opens a whole new bunch of interesting targets I can play with from home :) .

[Hagar]

More focal length is an understatement Marc. There does seem to be some variation between the right and left side stars so I would think and tend to agree with you that your camera is not quite square on to the scope.
Nice image just the same.

[multiweb]

Thanks Doug. Yes. New scope. It's going to take a bit of shimming and testing. Now it's better collimated, focuser is square... so I'm just waiting for clear skies to test. Looks like tonight might be the night here in Sydney. :) Btw I like what you're doing with the QHY9. Pretty crisp.

[bluescope]

I know what you mean about finding objects with longer FL ... I tried a Big Barlow just on my FLT110 and couldn't find a thing :whistle: so I gave up after an hour or so and went back to my normal 770mm ... so this is good work mate !

:thumbsup:

[multiweb]

Unless you have a pier and a "semi permanent" setup I think GOTO is always going to be of a challenge at long FL unless you spend a fair bit of time into polar aligning and building a model. I'm for ever moving around on my tripod so my alignment is not the best. :whistle: I'm trying to maximise my imaging time and minimise the "stuffing around", especially when I'm running on batteries. :lol:

[AlexN]

Too true Marc,

To get good go-to's with my C11, I had the tripod permanently set up in the back yard, and using EQMOD, I built a 30 star pointing model and could land objects on the ST9 @ 2800mm... however that was one whole night building an alignment model.. Very time consuming, not to mention that every time my mount goes to a dark site, the alignment model has to be re-done... Usually a sync will sort it out, but sometimes it requires a full re-do...