... Hello, On the above mentioned page you can read: 0.67 without any filters in path 0.63 with older filters and seperate 2mm IR Blocker (3mm total glass) ...
Thanks, Bud. It's an easy, photogenic pair of objects- It's nice to do something off the beaten path. The HII regions of the Cocoon Galaxies are surprisingly...
Thanks, Neil. It's an interesting pair of interacting spiral galaxies. A lot is known about it- it would be an even nicer target for a long focal length set...
What type of modification was made? Is it an Ha notch filter, or does it pass everything (including IR)? I believe the gradient is caused by a hot zone in the...
... I opened your image in Photoshop CS and adjusted the color balance to remove the red cast. The adjustments were: Red, -40; Green +15; Blue +15. This was a...
Dave: The modification to the off-the-shelf Canon EOS 10D is the removal of the IR filter. Other that placing a Hutech LPS filter in the imaging chain, there...
Thank you Mike. I have pre-ordered Ron's book and look forward to its delivery. In the mean time I am expecting Photoshop Astronomy by R. Scott Ireland to...
I have been using FWHM for focus for a while but just as a focus aid. I keep reading about it used as a measurement of seeing. I assume you just multiply your...
Tom, Jim, Steve, Wane,Neil, and Mike, Thanks for all the comments and suggestions. I will take them to heart and I plan on doing some "serious" reasoning with...
Bob, Sorry I left you out of my previous post. I appreciate you comments and suggestions as well. This light pollution thing is a real problem, not only to...
My long wait for an AP mount will soon come to a happy ending, which means it's time to start the CCD-camera selection process. This inquiry is about the...
Not entirely impractical...although an ST8 or 10 would give you better results. If you want to primarily do narrowband imaging, then head to the 8 or 10. If...
Warren: You and others are so fantastic - unraveling these CCD mysteries. I am just plunging into the mix of hobby/obsession/science/fun/art... After only 8...
... Sounds good. But you should receive something that lets you download Ron's book NOW, so you can read it right away. Mike -- Mike Dodd Montpelier, VA (37...
Hello Don: No problem. I have learned so much from my association with these astro related newsgroups and saved a lot of money. Maybe I should take that...
Hi, Yes, if you multiply your FWHM reading (in pixels) by your image scale, that will produce an FWHM reading in arcseconds. Does this equate to actual seeing?...
I agree with Neil. Ha/narrowband imaging _can_ be done with an ST2000 or similar "interline" chip camera, but the individual and total exposure times will...
... CS2. CS because it handles 16-bit images in most of the processing steps, and CS2 because it has added a noise-reduction filter. Mike -- Mike Dodd ...
Photoshop CS which is version 8. Bob firebirdthart <thart40@...> wrote: what version of photoshop do you recomend for post processing? ... YAHOO! GROUPS...
Hi firebirdthart (?), At least Version 8. (PS_CS) This version allows 16 bit images in layers. This is a very big advantage of version 7 and earlier. Version...
That's true; anyone who bought the new book, and does not know how to access the online preliminary edition, should contact me privately at support @ newastro2...
Quick focus exposures being less than 0.5 sec? George ... -- George Hall 12" LX200GPS ST-8XME, AO-7 Supercharge # 3777-2012 Dallas, Texas USA george2003 "at"...
Yes, based on my experience this would be more than adequate...frankly, even 1 second exposures on an appropriate star...then averaged out, should do the job. ...
To really capture the seeing accurately, you need: * Exposures 10ms or less (0.01 second) * An aperture of 10" or greater * The star must not be saturating in...
Hi Eric, I would like to offer up some other brands of cameras for your selection. SBIG uses Kodak chip based cameras that are both interline and full. Two...
Ron, Have you ever seen a chart of the minimum seeing that can be accurately measured vs apeture and pixel size? I wonder how many people who complain of poor...
I have seen such information, but don't have it at my finder tips. it is probably related to such things as Dawes' limit. I recall that you need about a 10"...
This is interesting, it seems counter intuitive to me. I would have guessed that measuring a longer exposure would be the way to measure seeing, ie. if the sky...
In order to measure seeing directly, you need exposures of 10ms or shorter. You will find that, typically, the longer the exposure, the greater the FWHM. If a...
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