Perferred Off Axis Guider?Posted By Andrew Riehl |
what sort of scope(s) will you be using it on?
Posts Made By: Andrew Riehl
January 17, 2003 12:13 AM
Forum:
Film Astrophotography - Imaging and Processing
January 17, 2003 12:21 AM
Forum:
Film Astrophotography - Imaging and Processing
Auto GuidersPosted By Andrew Riehl |
well, it would depend on the exact design of your controller to go into specifics. I would track down Norbert Tackman, He's recomended by sbig for modifying controllers and is a wealth of info on the subject. Try the link below:
http://home.earthlink.net/~ntack/
http://home.earthlink.net/~ntack/
January 17, 2003 04:39 PM
Forum:
Film Astrophotography - Imaging and Processing
Pro help needed on this worst case senario!Posted By Andrew Riehl |
you're trying to image at the worst possible time (twilight) with the worst possible situation-out of an open window looking over other houses in the winter. set the scope on the ground outside, let it cool, then try again.
January 19, 2003 04:55 PM
Forum:
Equipment Talk
Can I add "goto" to a Polaris (Vixen) Mount?Posted By Andrew Riehl |
Goto is not a cheap add-on...Not sure if a sky sensor will work with the old polaris mounts or not (there are some older 'pre-skysensor 2000' units out there that do go for a good bit cheaper than the ss2k's do). Another option--have you considered a set of digital setting circles? these would be a less pricy alternative (although I don't know much about them).
January 19, 2003 05:22 PM
Forum:
Film Astrophotography - Imaging and Processing
What is the advantage/disadvantage of 3...Posted By Andrew Riehl |
prime focus-- only uses the quality optics of your telescope with no other glass to mess up the image. Using a quality barlow or focal reducer (without eyepieces) to extend/shorten the focal length can also be considered prime focus. f/ratio's remain considerably faster than using eyepiece projection alowing for shorter exposure times.
Eyepiece Projection--greatly extends focal length (and increases image scale/magnification) at the expense of adding more glass to skew colors and scatter light. simple designs such as ortho's are best for eyepiece projection. With the higher magnification, seeing becomes much more of a problem, and the added exposure time also increases the negative effects of seeing.
A-focal--adds the cameras built in lens to the path. Most of these lenses are very low quality and mush up an image considerably. The only possible advantage of a-focal imaging is that it can be done without modifying the camera at all.
As for the programs you're looking for, many, many different ones can be found on the web by doing a search for 'convert avi to bmp', etc.
Eyepiece Projection--greatly extends focal length (and increases image scale/magnification) at the expense of adding more glass to skew colors and scatter light. simple designs such as ortho's are best for eyepiece projection. With the higher magnification, seeing becomes much more of a problem, and the added exposure time also increases the negative effects of seeing.
A-focal--adds the cameras built in lens to the path. Most of these lenses are very low quality and mush up an image considerably. The only possible advantage of a-focal imaging is that it can be done without modifying the camera at all.
As for the programs you're looking for, many, many different ones can be found on the web by doing a search for 'convert avi to bmp', etc.
January 19, 2003 11:58 PM
Forum:
Equipment Talk
Opinions pleasePosted By Andrew Riehl |
Hi Tim. I could think of a couple points to your video idea. Video is limited by the short exposure times required by a frame rate. Most frame rates are too short to pick up much detail at all in deep sky objects in anything sort of resembling real time. Now there are a few 'integrating' video cameras out there...these cameras can add several frames together to make one frame, or are adjustable to allow as long of an exposure for each frame as you like. You get a slower, 'choppier' video appearance, but a lot more detail can be shown. I'm not too familiar with the actual ease of use of such cameras (the front runner of which would have to be IMHO the SBIG STV), but I imagine its rather simple compared to the dedicated imaging ccd's. You wouldn't need to replace the secondary with the camera, just have a good focuser setup to allow the chip to come to focus (a fair bit more infocus than a normal eyepiece). A low f/ratio will give a lot more detail for the same frame rate.
I personally think you would be happier with a decent binoscope over such a video setup, but then again, I can't see through your eyes. Best of Luck to you (and by the way thanks for the Tak
)
Andy Riehl
I personally think you would be happier with a decent binoscope over such a video setup, but then again, I can't see through your eyes. Best of Luck to you (and by the way thanks for the Tak
)Andy Riehl
January 21, 2003 06:31 PM
Forum:
Equipment Talk
Star collimation question.Posted By Andrew Riehl |
I would guess your focuser is not square to the optical axis. (or, your collimators are not being held squarely in the focuser). Just a thought
January 23, 2003 10:19 PM
Forum:
CCD Imaging and Processing/Solar System
What is a flat?Posted By Andrew Riehl |
a 'flat' (flat field image) is an image taken to calibrate a digital picture. An image is taken of an evenly illuminated featureless object (such as a t-shirt, a wall, a sheet, a white card, a specially constructed box, etc.). This image records variations in sensitivity over the ccd frame--i.e. pixels that lie in the shadow of a dust particle will not record as much light as others; pixels on the edge of the frame will be dimmer due to vignetting. The flat field image records where all the various shadows and bright spots in the optical system are. Dividing an image by this 'flat field image' will brighten the dim parts, and dim the bright parts to even out the illumination and 'flatten' the backround. Here is a sample flat field image with vignetting and dust shadows (I'm past due for a good cleaning):
January 26, 2003 03:12 AM
Forum:
CCD Imaging and Processing/Solar System
Beginner's Equipment ChoicePosted By Andrew Riehl |
A color filter wheel for the stv has been available for some time. Just so you know. If you want the best autoguider money can buy, get the stv.
January 27, 2003 08:04 PM
Forum:
Film Astrophotography - Imaging and Processing
Stacking vs LayeringPosted By Andrew Riehl |
stacking is a term that refers to aligning images, then co-adding them, or median combining them. It is not the same as layering in photoshop. they are different tools used for entirely different things. stacking (adding/averaging/median combining) is one of the few things photoshop does poorly. I don't have any specific resources offhand, but look around on the web, you'll find lots.
Funding Member
