Keyhole Nebula - C11 at f/10 - Page 2

bluescope · #21 17-03-2009, 07:45 PM

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 !

AlexN · #22 17-03-2009, 08:03 PM

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!!

gregbradley · #23 17-03-2009, 08:27 PM

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 (Fred) · #24 17-03-2009, 08:33 PM

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 · #25 18-03-2009, 08:57 PM

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 (Andrew) · #26 19-03-2009, 01:48 AM

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 (Marc) · #27 19-03-2009, 09:40 AM

Quote:

Originally Posted by 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?

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

. 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 (Marc) · #28 07-04-2009, 08:30 PM

Well I just got my NB filters delivered today after 4 weeks waiting and obviously the weather is not playing nice.

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

and realised that I've been using the "wrong" alignment method with my subs

. So I have A LOT of data that I've butchered over the past year or so

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

and another go at it with a collimated scope this time.

Bassnut (Fred) · #29 07-04-2009, 09:01 PM

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 · #30 08-04-2009, 01:36 AM

I think it's a beaut pic!

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

Baz.

multiweb (Marc) · #31 08-04-2009, 07:30 AM

Quote:

Originally Posted by bloodhound31

I think it's a beaut pic!

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

Baz.

Thanks Baz.

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 (Doug) · #32 08-04-2009, 09:11 AM

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 (Marc) · #33 08-04-2009, 11:06 AM

Quote:

Originally Posted by 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.

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 · #34 08-04-2009, 06:19 PM

Quote:

Originally Posted by multiweb

Goto and finding objects is a bit of a challenge too.

I'm used to image at 650mm FL maximum so that was a bit of a shock.

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

so I gave up after an hour or so and went back to my normal 770mm ... so this is good work mate !

multiweb (Marc) · #35 08-04-2009, 08:37 PM

Quote:

Originally Posted by 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

so I gave up after an hour or so and went back to my normal 770mm ... so this is good work mate !

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.

I'm trying to maximise my imaging time and minimise the "stuffing around", especially when I'm running on batteries.

AlexN · #36 09-04-2009, 05:11 PM

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...