I'm noticing what seems to be a Proline 16803 hallmark: a 2-8 o'clock spike (that I doubt is coming from the CDK) Trivial really, but I'm curious to know what causes it...(Mike's seems to do something similar )
Man there is some detail in the billowing clouds there huh?
Niiice
Mike
Yes. I'm loving the aperture. You can get up close and personal.
Quote:
Originally Posted by peter_4059
Great M42 Greg. I don't think I've seen any other image of it with that much detail. The core takes on quite a different look in B&W.
Thanks Peter. Its the most I have gotten that's for sure. B & W shows the detail well.
Quote:
Originally Posted by multiweb
We had M42 wired, unplugged but this one is a definite reloaded!
Thanks marc.
Quote:
Originally Posted by mill
Wow!!! that looks very good with some very nice detail
Thanks for that.
Quote:
Originally Posted by SkyViking
Some stunning details in those clouds, great work!
M42 is always an interesting target.
Quote:
Originally Posted by Bigcrunch
A wonderful picture Greg, a lot of details in the heart of M42.I love this object in B&W.
bravo
Livier
Thank you for that.
Quote:
Originally Posted by Stevec35
You can't beat the large aperture Greg. Very nice M42.
Cheers
Steve
Too true.
Quote:
Originally Posted by Peter Ward
I'm noticing what seems to be a Proline 16803 hallmark: a 2-8 o'clock spike (that I doubt is coming from the CDK) Trivial really, but I'm curious to know what causes it...(Mike's seems to do something similar )
Nice. Some very fine structure there
When the Proline and Apogee U16M were in the hands of customers and little bugs were showing up with the 16803 cameras a common complaint was reflections.
This was usually from refractors that of course always had to have a flattener with a chip this large. Apogee brought out a mask for their camera that was quite effective so stray light did not hit shiny parts in the CCD chamber and bounce back and forth from the flattener to the chip. FLI did something similar although I do not see any evidence of a mask in mine like I had in my Apogee (I installed it myself). This issue became so heated it resulted in a whole new series of filters that were more advanced with antireflection coatings. That largely handled it along with the mask. So I would say the similarity between Mike's scope and the CDK is the corrector/flattener. My Proline has dew heaters installed as well. They are 2 bright orange strips on either side of the chip window. A bit crude perhaps and a little project I have is to blacken them. Perhaps the Proline also needs an aperture mask like the Apogee has which was a thin black metal cutout the same size as the CCD window. I think I will post with the FLI group to see if the Proline has one. If not it needs one. Also blackening the edges of my filters can be improved with another coat of matt black paint instead of the black permanent marker I have used which is still a tad shiny. So I think a mask if not already there, blackening the dew heater strips (there for the Florida guys anyway), further blackening of the edges of the filters should improve it. Beyond that I don't know. Different CCD chambers have different shiny bits that could be bouncing light around. The chip has no cover slip so its not that. I have seen some small halo problems associated with those. Beyond that a more advanced multilayer antireflection coated CCD cahmber window would no doubt help but how far do you take it? I know FLI switched to a better CCD window on the Microlines because of 2 guys having trouble with small halos around even only medium bright stars. I have seen some shockers of reflections on some sites with different filters. Something to know for the STX series if that aspect of the large chip has been provided for as it was a big issue there about 2 years ago now. I haven't noticed any reflection issues with STX images I have seen so far so it seems to be on the money there.
Greg.
Last edited by gregbradley; 29-11-2010 at 06:28 PM.
I had a check of other images I have done with different scopes and the Proline and the Microline and I can those spikes subtley on some brighter stars even with refractors.
So as you say a minor thing with the FLI cameras. I would put it down to the choice of CCD chamber window glass type (they do have different types as options), antireflection coatings they use or something in the CCD chamber that could be darker and is shiny. I don't see them with the Apogee U16M images.
It doesn't worry me either way but answers a question I had about why they were there.
An aperture mask may handle it then again if its the window it won't.
I'm noticing what seems to be a Proline 16803 hallmark: a 2-8 o'clock spike (that I doubt is coming from the CDK) Trivial really, but I'm curious to know what causes it...(Mike's seems to do something similar )
Nice. Some very fine structure there
Not from the Proline, Peter. It is caused by a shiny screwhead used for retaining filters that should have been painted flat black. The screwhead is on the carousel that is in the filter wheel. Paint it black and it goes away. You ought to see the Apogee filter wheel: they had big slots between the filters in the old version. Thought they would save some weight but forgot about:
1) light sneak paths around the slots
2) dust ingress around these slots that wind up putting motes in different places on the camera window at different points in time. Makes for a "delight" when shooting flats.
At least in the case of the FLI filter wheel you can paint the screwheads. Sort of are in a boat with a hole in it for the Apogee design error.
Lest ye think that SBIG is immune: don't forget about their NIR LED that they turn on inside of their filter wheel that is used for indexing of the older types. Not sure if they repeated that silly error on the STX "Boatanchor": not enough have shipped to get a reasonable sample size for assessment yet.
The cool thing about that NIR LED is that it is perfect for creating RBI artifacts since RBI is greatly aggravated by NIR light. And since it will involve "sneak paths" inside the filter wheel and shutter, it is variable and not so easy to calibrate out. I suspect some of the flat fielding problems people have reported from time to time is related to RBI and the presence of an NIR LED *INSIDE* the filter wheel but *WITHOUT* an RBI mitigation mechanism built in.
Obviously those fine scientists in Santa Barbara weren't thinking about RBI when that design mistake was made. Not clear to me that they understood what RBI actually was. Have they got a handle on it now in the ST8300 or the STX? I think QSI (the new "SBIG" as I see it) has taken the position of "wait a while before shooting the next image" as an RBI mitigation strategy with their formerly grossly overpriced QSI583: others may call that the "ostrich" approch of sticking one's head in the sand and hoping for the best.... good work when you can get it and can convince your advocates/sophosits that it is a viable strategy... got to love it: all the Einsteins these companies have as customers.... brilliant, every one of them!
And you thought mine was in your face!
Great to see the weather giving you just a peek of what this lovely scope can do.
Some very nicely resolved detail to the cloud filaments, with better weather, this'll be a lovely image.
I'm noticing what seems to be a Proline 16803 hallmark: a 2-8 o'clock spike (that I doubt is coming from the CDK) Trivial really, but I'm curious to know what causes it...(Mike's seems to do something similar )
I'm not sure where they are in my images
Although I have seen such features in other images, I recall Richardo saw them in his 10" F4 astrograph too and he wasn't using anything FLI. Certainly haven't noticed this effect in my images though. I get some unexplained flare like diffraction spikes around my bright stars - the origin of which baffles me but obviosuly something in my imaging train and I have just grown used to them - but not these distinct diagonal lines..?
[QUOTE=ptc;661391]Not from the Proline, Peter. It is caused by a shiny screwhead used for retaining filters that should have been painted flat black. The screwhead is on the carousel that is in the filter wheel. Paint it black and it goes away.
Thanks for that Richard. I would never have suspected something so simple. I'ff fix that.
Cheers,
Greg.
Last edited by gregbradley; 30-11-2010 at 07:05 PM.
Greg
I had this artefact in the first Proline camera FLI sold me which was a complete disaster in so many other ways, but that's another story. See the attached JPG.
While you have the cover off, you might also want to check the slop in the filter carousel, another trade-mark FLI design flaw. There was about 3mm slack in mine, and this causes visibile tilt and optical aberrations, particularly when your CFZ is measured in microns (about 60microns for a red filter I think). The unbelievable and utterly ridiculous advice from FLI was "take a link out of the chain"!!!!! The SBIG implementation is fantastic - you simply adjust the tension on the central spindle to the point where the carousel rotates smoothly, but there is no rock in it. Then there is the superb implementation of how they clamp the filters in position - no utterly stupid miniature screws (all of which are shiny in nature in the Proline, and all the source of reflections).
Woa... that is scary to hear that even the top gear has its flaws. I'll never complain about my stuff ever again. Didn't spend a fortune on it which helps.
Livier
