Posts Made By: Maurizio Di Sciullo

Hi again Friends,

Same data as with the Saturn image; RV-6, excellent seeing, clueless operator. I didn't like the way Registax sharpened the image, so I went to MaxIm, which helped a lot. I was amazed to see how many tuly poor shots the program had selected for processing, so I had to go back and re-select them manually. A bit of a pain, but certainly nothing like the old days, where you had to do *every single thing* by hand! I think this is the crater Aristillus, but I could very easily be wrong.

Maurizio

Hi Folks,

Last night I tried to shoot M-51 with my E-155 (6" f/5), HX-916, and TT filters. I tried to use my "SkySensor" goto mount to center the galaxy, as I couldn't see it in the eyepiece at any power (light pollution). After having gotten close enough, I got the galaxy approximately centered, and started shooting. After about 30 frames, I stacked about 20 of the best 15-second exposures to see how I was doing. Not bad, I thought, but still a bit noisy when I went to heavy non-linear stretching. I finally accumulated about 100 frames, and 10 each of R-G-B for color.

Upon processing, I was greeted by a nasty surprise; no matter how many frames I stacked, I couldn't get the "noise" out of the frame. It was in all the data; the color as well as the "L" data, and it was practically ruining the shot. Frustrated, I was about to hit the "Flush" button on my keyboard, when something struck me; the "noise" was confined to a roughly circular pattern in the center of the FOV, while the corners were free of it. With my jaw slack, I realized what I was looking at; the "noise" was actually light pollution, and the dark area was vignetting caused by my smallish secondary (the 'scope was originally intended for planetary observing, not wide-field imaging). If I had been imaging from a dark sky, I would have probably captured a beautiful shot of the galaxy, but instead, got one that looked like it was being viewed through static from an old t.v. set. I was wondering why a camera as clean as the HX-916 would still be showing noise after combining about 75 frames, and I got my answer; it wasn't noise from the camera, it was noise from society.


Maurizio

Hi All,

I discovered last night that my old SkySensor has a severe error in RA tracking rate. While trying to image M-51, I expected to have to make dec adjustments for polar alignment errors, but to my surprise, I was very close - just two adjustments all night. However, RA was another story. I was amazed at how over-tracking the mount was. It was out-running the Earth's rotation to the tune of about 6 arc-seconds per minute! What's worse, is the fact that it wasn't constant. Sometimes, it would hold it's position for as long as 7-8 minutes, and sometimes, it would over-track almost an arc-minute in barely 2-3 minutes.

Therefore, if I wish to have any hope of getting some imaging done, I need a new mount. Goto is not important to me. I just need a mount that will be reasonably cost effective, hold nothing bigger than my 6" f/5, and preferably, have an input for a guiding camera. Money is always an issue, as I know exactly what I would buy if I were financially independent. It must have some semblance of transportability, as it must fit, along with my 'scope, in my 2002 Corvette Coupe (which is a hatchback with surprisingly good cargo space). I thank you all in advance for your thoughts, and please don't be shy about your recommendations. I have already had one person suggest Orion's Atlas mount, as he said he has good luck with it, and it was a bargain at about $800. Anyone have any supporting/contradictory info?

Thank you all,

Maurizio

Folks,

If there's anyone here who could give me a pointer with Registax, I would really appreciate it. Specifically, no matter where I set the the quality value, it just goes through and selects *ALL* the frames anyway! Obviously, the results are far from optimal unless I go through and maunally look at them all. When you have over a thousand frames, needless to say, it can be a real pain in the rear. Can anyone offer any suggestions, or vector me to a site that has some kind of tutorial on how to use the program?

Thanks,

Maurizio

You're right, today is my first day of posting.

Maurizio

Thank you for your input, Eric, and you've touched on the subject I'm most concerned about; the software's accuracy when it comes to separating good frames from bad. I know when I was shooting with my CCDs, I would have hundreds, sometimes a couple thousand frames, and it was a Herculean task to go through them all to identify the best ones - especially when it was 7:00 a.m., I had just been up all night fighting off mosquitoes the size of chickens, dodging the occasional drive-by bullet, and just finished dragging my 250 lb. telescope back into my garage. If we now go to the webcam's ability to produce fifty times as many frames as the CCD for a given time frame, the ability to efficiently sort the good from the bad becomes imperative.

Again, thank you Eric.


Maurizio

Beautiful picture, Tyler.

I live in Coconut Creek, where there are no coconuts, and there are no creeks, and on Osprey Terrace, where, believe it or not, one can occasionally spot a mated pair of Osprey lazily gliding about....


Maurizio

Tom,

Ringing is a complex phenomenon caused by the right combination of mask radius, patterns of light and dark in your frame, the physical dimensions and separations of those patterns, and pixel grain. Change any of those variables, and the ringing will be affected, especially if you shorten the mask radius you've sharpened with, or the strength with which it was applied. Try sharpening with a shorter radius, for starters, and see if that helps. I will upload a few files later for your inspection.


Maurizio

Mike Wirths said:
. Is it just me or is the trend to process Saturn with a greenish tinge? I know in my 30" Starmaster which will pick up subtle colour like crazy I never notice anything but a creamy yellow with maybe a hint of red on the globe. Guess thats down to personal preference.

thanks

Mike Wirths

Mike,

First of all, congratulations on an excellent image - it is very hard to find fault in such an accomplished effort.

I am interested in your observation with your 30" telescope, especially your thoughts that the color is fairly uniform, a somewhat creamy yellow tinge. In my telescope, I observe the same thing. Further, the next chance you get, have a look at Titan. In my E-258, the disk has the color of a catcher's mit; the orangy tan color of heavily cured and tanned leather. let me know what you think. I include my perception of Saturn in CMY, and I'm curious as to how it compares to the view in your big 'scope. Just a caveat, I have a rep for very subdued processing in my images. I look forward to your thoughts on the matter.

Maurizio

Folks,

I have read the various texts by many, and I think it is excellent that we have a good discussion about these things. A few things;

First, I understand why Roland and Damian think the way they do. Specifically, the reason we think differently is not because *I* haven't imaged under poor skies, but rather, because *they* don't have night after night of laminar flow experience to draw from. Once the atmosphere starts quieting down, it then falls on the optics, operator, camera, and processing technique to make the image a success. I have had the luxury of many sub-arc second nights to compare instruments, and I assure you all - the optics absolutely positively make a difference. I regret that some of this discourse was precipitated by a mis-quote of sorts by Roland; anyone who read my original post knows that I never dismissed the importance of atmospherics to imaging. But I, for one, know for a fact that the atmosphere isn't everything.

Secondly, the entire effort of high-resolution imaging is a statistical trial; sooner or later, all points on Earth will fall under laminar flow. The question is how often, and will one be able to catch it. The reason webcams have been so useful in planetary imaging, is because they allow more frequent, and swifter sampling of the atmosphere. Look at it this way; the probability of catching laminar flow is far greater if you are sampling 10x per second (i.e.; 10 frames per second), for only 1/30th second, than if you are sampling once every SIX seconds, for .4 seconds (my sampling rate and exposure time when shooting Jupiter at f/33.). The probability of a .033 second window of laminar flow occuring, is an order of magnitude greater than a window lasting .4 seconds. The burden then falls on the camera, and the optics to make the best use of this greater sampling power. A perfect example of this is Wes's recent shot of Plato. Using his excellent 18" with Zambuto optics, Wes was able to record exceptional detail on the crater floor, and to my recollection, he doesn't live in Florida, but right smack in the middle of the country, in Oklahoma. Note, however, that he does have excellent optics. The webcam allowed him to sufficiently sample the atmosphere to catch enough instances of laminar flow, to overcome its low s/n and make a hi-res image. The result is an image with well below arc-second resolution, which I doubt could have been done with a 60mm Tasco in Florida, as Roland and Damian seem to suggest. In fact, practically *ALL* of his images shot with Carl's mirrors carry the mark and air of exceptional quality, and I, for one, don't think it's an atmospheric fluke. You guys with Carl's mirrors have real potential in your hands, so don't let *ANYONE* tell you that the great level of quality you posess won't amount to anything in imaging.

As webcams become better, and better, they will require fewer, and fewer frames to realize the current level of resolution. Eventually, it will be possible to utilize a single frame to achieve maximum resolution, owing to improvements in s/n ratio, and full detector well depth. Combined with even faster downloads, more accurate selection software, and larger hard drives, imagers will be able to literally sample an entire night's seeing at their leisure, picking that one frame that happened to be shot just when the atmosphere went *PERFECT*. Under such circumstances, there will be practically no limit with regard to useful optical quality, and aperture. The bigger the better, and unlike my previous philosophy that a 10" - 12" is about the practical limit, I believe that guys running around with 30"s will have a truly realistic chance of seeing the full potential of their optics realized....and that will be a glorious day (or night) indeed.

Maurizio