M20 Triffid - slowly gettn there...[repro]

[leinad]

VC200L; 350D UV/IR
F/9, darks, bias, no flats.

5x ISO400 6min
5x ISO800 6min
5x ISO800 8min
5x ISO1600 6min

This week the focal reducer should arrive which hopefully will improve my shots. F/9 can be a pain.

I thought I would have got more data out of these shots, though the moon was around, scope was imaging at F/9, havnt got around to getting good flats as yet.

I still need better SNR shots :shrug:

[Bassnut]

Looks promisng Ieinad, wouldnt bother with so many exposure options though, 4 sets of darks is a bit too much work.

[gregbradley]

F9 is a bit harder. Which of the ISOs you used gave the best result? The ISO1600 or the ISO800? ISO 400 coupled with F9 is probably way slow.

Greg.

[Tandum]

Very square stars .. looks like a typical VC200L shot to me :)

What was someone saying about lack of colours in DSLR star shots, plenty of colour here :)

I've found shorter exposures reveal just as much detail as longer ones with the Vixen. ie: 10 minute subs give me as much data as 20minute subs with the reducer. It could be I was just swamping the camera :shrug: but I found the same thing the other week with the starlight camera. 10 minute subs showed as much detail as 15 minute subs? suck it and see I guess :)

[leinad]

Yeah. I'll process them all int their respective ISO runs, and see what difference is noticable between them. didnt think of doing that inititally :P



ISO800 seemed to provide the best results. i'll have to process them all individually, to get an idea of the adv/dis-adv of each.



Interesting. Soon as the FR arrives, I'll do a few tests and let you know how it goes.

[AlexN]

Looks pretty nice to me Daniel.

As Fred said, pick one exposure setup and stick with that...

I think either the 8min ISO 800 or 6min ISO 1600 would be the way to go...

If you stack 5min ISO 400 subs with 8min ISO800 subs and 6min ISO1600 subs, your longer exposures extra detail can be rejected by certain stacking modes, doing an average combine of these exposures will remove some of the deeper detail from the longer sub, as it will use the average pixel value... the 5 min ISO400 shots will have much lower pixel values than the 8min ISO800 subs, and hence, precious data is lost...

For MOST targets, just run the longest exposures you can at the ISO level that produces good results without too much noise (noise shouldn't really been an issue if you're taking a decent amount of darks.)

Good going, looks like you're coming along nicely, I look forward to seeing how you go with your reducer!

[Hagar]

Nice image Daniel, Yes you can tell it's a VC200 but you do get use to the diamond shaped stars. Small tweaks on the collimation sometimes helps to round the stars a bit but believe me it is a tiny adjustment.
The images overall are very good but I wouldn't muck around too much with multiple exposure or ISO exposures for an image of Trifid, definitely for something like Orion Nebula where yu have a reason to do it.
You could darken the background a little using levels but otherwise an image to be very happy with. Full calibration is the real key to getting the best from your images and it is a lot easier with one set of exposures. Longer subs will increased the signal to noise ratio and make processing the fine detail a whole lot easier so don't discount longer subs but there is a point where the thermal characteristics of an uncooled camera equate to a diminished return on time spent. EXPERIMENT and have fun.
Great image. Keep them coming.

[jjjnettie]

I love this.:D

[gregbradley]

I'm also curious whilst you are checking out the different ISO results which ISO preserved the star colours the best.

I predict the lower ISOs will.he ISO is simply the amplifier gain so higher ISOs amp everything up. Another reason why ISO800 is a good allround choice.

Greg.

[multiweb]

Great shot. Very sharp in focus. :thumbsup:

[leinad]

Thanks all for the comments. The focal reducer arrived yesterday and various adaptors, I hope to hit this target again and test further(get more data)

I managed to work out CCD Inspector last night; from the number of shots I'd taken previously the curvature and viewer maps showed collimation to be reasonably Ok. Perhaps just a tiny tiny adjustment is needed, also to correct the focuser tilt.

[leinad]

I tried to get a little more data out of this which was a mission in itself.
Im thinkn a lost a little in the process also.

funny enough I processed the diff ISO groups and couldnt get a better stack comapred to the group stack. May have been doin something wrong(trying to many options and forget which was best).

anyway here they are. :shrug:

[multiweb]

Defintely got as better color balance and more details on the repro. You should do a star mask and use the stars from the first version then blend them back in and you'll have a superb shot. :thumbsup:

[Tamtarn]

Better colour balance in the repro Leinad. Nice job :thumbsup: