NGC 6357&6338 in 3nm NII 16min

[avandonk]

Everything came together last night except for the cloud that spoiled things only managed two eight minute frames of real data. There was too much chance of rain to persist.

Here is a full resolution version 10MB

http://d1355990.i49.quadrahosting.com.au/2012_05/NGC6357&6334_NII_16m.jpg


I have worked out where focus should be slightly offset to make the corners 'better'.

Bert

[cventer]

Bert

Showing good potential, but focus is still looking soft. At such high f ratio, hand focusing with bhatinov is not going to cut it.

I would suggest you install focusmax and get a few calibration runs in with this. With Atlas you will only need 3 or 4 runs because of its accuracy. Will take you 15 min max to calibrate focus max and then you wont have to worry about perfect focus from that point on. just slew to mag 4 or 5 star. Press focus and watch it do its thing. When done slew to target you want to image and start imaging. Get latest version from Focusmax yahoo group files section as its more up to date.

[Mighty_oz]

Lovely image there, have to agree with Chris looks a tad softish ?
Wish i had this gear tho :) Keep'em coming Bert your on the cutting edge.

Marcus.

[avandonk]

I do not think that anyone understands what I am trying to do. My aim is to make deep mosaics of faint stuff using NB and colour. I do not care that my stars are not perfect round orbs so much loved by the people who think that a point object can be represented by a circle of indeterminate radius only depending on it's brightness. Even this representation is a fallacy.


Bert

[avandonk]

Chris I find my major problem is with the primitive program called MaximDL. It is an over rated piece of junk as it can only do one thing at a time. It stops guiding when it is downloading an image. It only seems to be capable of one simple task when all hell is breaking loose with all other parameters.

The guiding is pathetic as is the aquisition of the guiding image.

It is very annoying that it hunts for the guiding when it is so fundamentally slow in working in real time. It is again a piece of junk!

When will they release a version that takes advantage of multiprocessor computers.

Or will that be an other $600!

Bert

[Moon]

Maxim DL fan club to the rescue here.

That statement doesn't make sense unless your guide exposure is very short - like 0.001 sec or something crazy like that. After the guide correction is sent to the mount, what is 'stopped' exactly?
MaximDL uses subframes that are very fast to download (I use USB 1.0 with no issues) and you shouldn't be sending mount corrections very frequently anyway.
James

[avandonk]

Can you then enlighten me why all MaximDL windows show no change while image download is progress. Then the so called guiding slowly walks back to where it should be. Even the guiding pulses seem lethargic to the point of what seems to be overcorrecting in a tub of tar!

I found that a two second exposure was a bit better than something faster. It was still pathetic!

Bert

[Moon]

Bert
What guide exposure are you using? How long can your mount track until a guider correction is **really** needed? I usually go 10 or 15 seconds between corrections. No point moving the mount if it's not needed.
James

[RickS]

Maxim deliberately doesn't guide while downloading an image from the main camera because the USB traffic generated by guiding reportedly caused image artifacts, at least with some equipment combinations. I'd like to have the option to turn this off and see if I can get away with it on my system...

Cheers,
Rick.

[stevous67]

If you are dissatisfied use something else. As usual, opinions differ, as I find Maxim DL extremely productive and functional.

Steve

[dvj]

I can definately tell you are frustrated based on your comments about MaximDL. While no software is perfect, download in a Proline 16803 is minimal, and you are not taking an exposure when the download is happening. And typically image dithering is used before starting the next frame. That get's the guide star "back in the box".

I thought you were using an Atlas focuser on the RH200, so focusing should be extremely precise at f/3 with this device. My minimum increments are 200 steps with the Atas attached to my FSQ. It's amazing what a tiny shift will do even at f/5!

Given the short exposures, the Paramount MX that you are using should be more than up to the task with minimal autoguiding. At least, I think that's the mount you are using.

Lots of variables at play eh?

- polar alignment
- focus
- flatness of field
- filter flatness
- flatness of the ccd array in the camera
- square connections of all addapters betwen the camera and telescope
- autoguider settings
- tracking of the mount
- quantity of beer consumed prior to imaging

Yep, welcome to astrophotography. :welcome:

[dvj]

BTW, by looking at your 10mb image. I would say you have tilt in your system. Upper left corner is soft, while the lower 2 corners are sharper.

Have you tried other filters, or an L channel to see of the image results are reproduceable?

Anyway have fun. It's the journey, not the destination.

j

[RobF]

All too true in AP. It's nice when you get a regular win though (sort of like stopping off at a semi-scenic station during the journey :P).

Bert, Maxim's power is in it's tweakability, and you'll often want to dither anyway as John and others have said, so you'll giving guiding time to settle before next subs most of the time anyway (you don't have to though). Other programs may have slicker interfaces and get you going faster, but there's so much you can adjust in Maxim as you learn more about stengths and weaknesses in your gear (err, perhaps strengths and lesser strengths for the gear you're using now!)

Hope the weather co-operates more in future. Very promising image.
Maybe you need to consult with Fred on nuking "pesky stars" :question: