I'm new to the CCD forum, and have posted a couple of times in the epuipment section, and noticed many users of the SPC900NC in the group.  I've looked through the list of old posts, and have a couple of questions that I'm sure have been asked many times, but I couldn't find the answers.  I'm new to CCD imaging, and want to make sure I get the right setup before I continue.  I appreciate any and all helpers!  I have an 8" Newtonian Reflector (F/4, 800mm focal length,SPC9000NC)

1.  Is it necessary to get around 4000mm focal length and .25 arcseconds per pixel.  If so I would need about a 5X barlow (unfortunately a shorty).  Would this be pushing it with moderate seeing conditions?  Also, what books or reading material can I find with the formulas,or am I making it too complicated? 

2.  Which Resolution setting is best- some say 640 X 480, some 355 X 288?  I noticed much less noise in the 355 X 288.  Any suggestions?

3.  Is it necessary to capture in .AVI format? Mine seems only to have .mpg in video format. I've looked everywhere on the program, but can't seem to find where to change it.  It seems someone posted this issue before, but I can't find it.  I thought there was an additional download from Philips, and I thought it was for this issue.  Help!

4.  I've noticed some say no IR/UV filter for the webcam, others say yes.  I was looking at the Baader IR-Pass 670nm, and was wondering what everyone's experienced. 

to uncomplicate it somewhat- heres a basic guide- i assume you mean planetary?

1-  you shouldnt image in 'moderate' seeing, for good seeing figure f/15-f20, for excellant seeing go for f/20-f/25

2- 640X480 is what you want

3- you can probably capture and process many formats- id use the AVI though, just use another capture program

4- get the filter

NutoAP:

Is it necessary to get around 4000mm focal length and .25 arcseconds per pixel.

As noted above f/20 or so is a good place to start, but you'll want to go to f/30 or f/40 once you get some practice. Once you've practiced at a coarser imaging scale for a while, move to a finer scale. Specifically, choose a focal length that yields an image scale of 1/2 to 1/3 of your scope's Airy disc. The focal length multiplier calculation requires that you determine the size of the Airy disc for your scope, the pixel size of your camera, then determine the focal length required to achieve the desired image scale, and given the native focal length, you arrive at the desired multiplier. The focal length multiplier will be high if you're using a "fast" newt (I use a FLe of 9000-10000mm w/ a250mm scope, others using 250-350mm scopes go out to 12000-15000mm).

NutoAP:

Which Resolution setting is best- some say 640 X 480, some 355 X 288?  I noticed much less noise in the 355 X 288.  Any suggestions?

Do not bin pixels, or you will need some really long focal lengths (see image scale comments above). Whether, or not you use a subframe, or ROI, is dependent upon the "size" of your subject in the camera frame. I typically use a 1/4 frame ROI when working with small subjects, like Mars, so that I can run higher frame rates (my camera allows up to 112fps on 1/4 frame, but only 60fps on 640X480, though the pixel size is the same for both).

You are dependent on high frame rate captures to catch momentary still air. The longer the sequence, the better the chance of catching a few good frames (up to the point were planetary rotation interferes, different rotation rates and distances dictate differing sequence limits).

NutoAP:

I've noticed some say no IR/UV filter for the webcam, others say yes.  I was looking at the Baader IR-Pass 670nm, and was wondering what everyone's experienced. 

I use IR cut lum and RGB filters on my monochrome camera, unless I'm specifically imaging NIR, When I used a OSC for chrome, I also used an IR block. Whether you want the potentially color corrupting influence of IR is entirely up to you (It helps on Mars sometimes).

Robert

       Thanks for the response, I really appreciate it!

      I do want to make sure I understand correctly, so I apologize if I sound a little stupid.  Yes, this is for planetary work.  With my setup, do I go with a 5X Barlow, or can I count on the camera for some magnification(if so, how much)?

2.  So, niether 640 X 480 or 355 X 288 are binning?  Everything I've been reading tells me to go with the lower resolution and as low a fps as I can get (5-10 fps).  Is this misleading info? 

3.  Will the Baader IR-Pass 670nm be beneficial at all?  Will it suffer color loss, since it's not a monochromatic camera? 

As noted earlier, use 640 X 480 (if that is the native "full frame" for your camera).

NutoAP:

Everything I've been reading tells me to go with the lower resolution and as low a fps as I can get (5-10 fps).  Is this misleading info? 

I'd call that info misleading! The idea behind webcam (planetary) imaging is achieve the highest final resolution by capturing as many frames as rapidly as possible, then select the best and stack. The only limitations to frame rate, for a set image scale, are your camera's sensitivity, the communication port/computer (typically the HD), and  the capture program you use. If you can get enough light in to achieve a decent exposure, run as fast as possible.

When I was using a usb1 camera, I was limited to 5-10 fps for uncompressed capture (faster than that, and compression reduces resolution for usb 1). Using a usb 2 camera, I command lum exposures at 112fps for Mars (ROI subframe), 60fps for Jupiter, and 30fps for Saturn (very low frame rates to achieve exposure for Uranus and Neptune). The RGB exposures are about 1/2 these rates.

If you are using a usb 2 cam, use as high a rate as you can while getting a good histogram fill (good exposure), if using a usb 1 cam, keep the frame rate to 10, or below.

If you have an IR cut filter (~400 to 700nm passband), put it on the cam. If you have an IR pass, save it for bringing out details on Mars, otherwise set it aside for now (I use NIR for Mars, Jupiter and moons of Neptune, but only when combining with other filters).

Robert  

 Thanks Robert,

              I can at least have as much info with me before going out into the field.  Last question:  If (eventually) I look to get a focul length longer than with a 5X Barlow, how would I do that, or would it take another scope?

             I appreciate your time,

                                              Mike

I have the SPC camera myself. You should use a different program than what comes with the webcam to make your AVI's. There are several freeware ones available. I use QCFocus. It's very easy to use, has a simple clean interface. I don't have a link, just google for it.

The SPC has some strange behavior when using different frame rates. Some of the higher frame rates produce noisy horizontal bands in the image. I think there could be some electrical interference from the higher frame rates affecting the video signal. I find the best images and noise-free dark frames are at 10-15 fps on my camera. It also affects the exposure time. You get the longest possible exposure time at the lowest frame rate.

About the barlows, especially the cheaper shorties they don't always give you a good image. You might get field curvature. That means you can focus near the middle of the field, but it gets worse toward the edges, or vice versa, focus at the edges but not the middle.

If you want to try going higher than 5X you can stack barlows. A 5X stacked with a 2X gives you 10X. But you can't keep going up forever. You'll run into the law of diminishing returns. you won't be able to reach focus. Or if you do it will be blurry at best. Also the image gets dimmer each time you go up in magnification, since you're spreading the light over a larger area.

     Thanks for the help, I appreciate everyone helping out, and I expect to return the favor for someone else someday.  I just wanted as much knowledge as possible before trying it.  Otherwise, I'd be going in blind and not know what mistakes were made. 

        How do you treat the gain, brightness, gamma, and saturation?  I know to turn the auto-focus off, but I've also heard some leave the white balance alone, and others turn it to outdoor.  Sorry for all the questions, but I haven't been able to test it due to weather over here!

                           Thanks again!

leave the brightness alone- should be centered, adjust it with the shutter speed, gamma is usually off, gain is best lower (adjusted with the shutter speed)- increase the saturation, wx Astrocapture might be better for you

NutoAP:

Thanks for the help, I appreciate everyone helping out, and I expect to return the favor for someone else someday.  I just wanted as much knowledge as possible before trying it.  Otherwise, I'd be going in blind and not know what mistakes were made.

No problem. I have learned much from the good people here, and by experimentation. It's ok to make mistakes, try things out. You will soon learn what works and what doesn't. Keep a good record of your results,

Clear skies (I wish... haven't seen it in weeks)

About frame rates ...

1. This depends to a large extent on the software and camera you're using. The camera and/or software compresses the data as it's saving the file. This adds noise. In all but one of the camera/software combinations I've used, the amount of noise added increases as you increase the frame rate. So, generally, with a standard webcam and its supplied software, you want to use a high frame rate for focusing and adjusting, then a lower frame rate for capture. But read on.
2. The target is another factor. If you're capturing images of colorful stars (double stars of greatly different colors, for example) then use a low frame rate as there is no great advantage to having 1,000 frames for stacking over having just 100. Experiment with different rates to get the best result. But for planets, you're limited by the target's rotation. For Jupiter and Saturn, use higher frame rates to avoid blurring of details. With Mars you can use lower frame rates.
3. Seeing also determines which frame rate is best. However, if seeing limits my frame rate, I generally bag it for the night.

In general you want to use as high a frame rate as possible, while avoiding compression noise as much as possible. And this depends on your camera, software, and target.

I do a fair amount of the above types of imaging. For Jupiter and Saturn, I normally use 15 to 30 fps. For Mars I generally use 3.5 to 15 fps, depending on camera and software. For lunar imaging I am now using a DSLR mostly, but for webcam imaging of the Moon I typically use 5 fps. For h-alpha solar imaging, in good seeing you will get so much granulation and other continuum detail that it will hide the compression noise, so any frame rate will work as long as it's fast enough that you don't lose detail to seeing or target detail movement.

chipdatajeffB:

For Mars I generally use 3.5 to 15 fps

Jeff, what kind of camera are you using???

High frame rate, given sufficient exposure, always beats low frame rates on planetary work, if the camera, codex, and computer can keep up.

Mars is bright. I've never run less than 60fps for lum, 30fps for RGB on Mars (250mm cass @ f/35 to f/40 since going to the usb2 Lumenera). Since Mars is small, I typically select a 1/4 frame ROI and command 112fps for lum(actually get 80-90 fps depending on HD fragmentation), 1/2 that rate through RGB filters. Many more short, turbulence beating exposures, more frames to select from in stacking, and better overall photos.

Doesn't apply to older usb1 cameras!

Robert

galacticphoto_1234:

chipdatajeffB:

For Mars I generally use 3.5 to 15 fps

Jeff, what kind of camera are you using???

I haven't had a good enough night to shoot Mars yet this year. But mostly I've been using an SPC900NC, a ToUCam Pro 840K, and both DMK and DBK mono and one-shot color 640x480 firewirecams/usbcams. With the cameras from The Imaging Source, I use their Icapture software.

For the webcams, I have been using the standard Philips camera software, but just a couple months ago I switched to K3CCD as I found it's been MUCH improved since I last used it about 3 years ago.

For solar, I have used the Philips cameras but now use the DMK camera exclusively as it outperfoms all my other cameras in h-alpha capture.

I now mostly use a DSLR for lunar, but have done quite a bit of it with the Philips and DMK cameras. It's kind of a toss-up as to resolution and dynamic range, but I give the DSLR a slight edge and it's MUCH easier to use. With the DSLR, I only need 25 to 50 frames to deal with noise buildup.

I do plan to switch to a Lumenera camera, however, as I want more resolution. If I can make one higher-res camera do the work of my former menagerie of cameras, then I'll do that. I now need a fairly bulky and heavy case to carry all my cameras, cables, barlows, filters, etc. ... and I'd like to simplify that if possible.

High frame rate, given sufficient exposure, always beats low frame rates on planetary work, if the camera, codex, and computer can keep up.

I'm generally pretty careful about using words like always ... it has given me no end of trouble in the past. I think you're generally correct, however, given the rest of your statement. The importance of the codec can't be minized -- that largely determines your noise level. If you have good exposure and the camera is decent, then the codec's compression factor will add noise/limit resolution of the finer details, so you must be careful. It also is a determining factor in the available frame rates. Not all camera software will go above 30 fps or below 5 fps. One of the things I REALLY like about the DMK/DBK cameras is they have a wide variety of frame rates from very low to very fast.

Mars is bright. I've never run less than 60fps for lum, 30fps for RGB on Mars (250mm cass @ f/35 to f/40 since going to the usb2 Lumenera). Since Mars is small, I typically select a 1/4 frame ROI and command 112fps for lum(actually get 80-90 fps depending on HD fragmentation), 1/2 that rate through RGB filters. Many more short, turbulence beating exposures, more frames to select from in stacking, and better overall photos.

You needn't use high frame rates to beat seeing -- you can use short exposures. They sort of work together, but primarily when you go to lower rates and longer exposures. One disadvantage of using high frame rates is that in order to produce AVI files of reasonable size (smaller is generally more reasonable than larger) you need to produce shorter overall AVIs. While that's not a huge problem, I find it troublesome to deal with many gigabytes of files, with thousands of frames, during processing. In the first place it eats up disc space / requires a larger interim drive (thumbdrive or whatever) to transfer files. In the second place a larger AVI file greatly bogs down post-processing software once you get above about 2 gigabytes. And some OS versions limit you to about 2 gig. What CAN be done is not always what Should be done.

And remember there is a HUGE difference between the Lumenera cameras and good software versus the typical webcam, which is where this thread started out ...

chipdatajeffB:

remember there is a HUGE difference between the Lumenera cameras and good software versus the typical webcam, which is where this thread started out ...

That's why I've continually noted that usb1 cams (implying cams and associated process control SW) don't necessarily use the same settings, or get the same results that I've referenced!

(several short exposures are nice, but 1000 short exposures, under decent seeing can be better)

Robert

Hi guys, is there a good codec that you could recommend? So far I have just used the spc900 with its own drivers, and QCFocus as the "front end" to make avi's. And how would you install it and ensure that your program is making use of that particular one?

Thanks for any info.

Thomas

It might be helpful to talk about the number of frames in a stack rather than the frame rate.

I find that with webcams and firewire cams my lunar images need no more than about 400 good frames, and these typically come from AVI files of around 900 to 1200 frames.

My best Mars images are about 1,000 frames of perhaps 10 times that many, requiring multiple AVIs in a short period. I've processed as many as 5 at a time to get the best results.

My best Saturn images are about 500 to 1,500 of about 3,000 frames from a single AVI

My best Jupiter images are about the same as my Saturn images, fewer than 1,000 frames from about three times that many.

My best solar images are about 250 of 1,500 frames.

Now, I've had a few nights where I can use about 75% of the frames in an AVI, but that requires excellent seeing throughout the AVI. Most of us image from urban or suburban skies, where it's rare to get photometric nights -- probably only a handful of nights per year of really good seeing. There are exceptional locations, of course.

My point here is that you don't need 10,000 frames to get a good image. Now, having said that, most of my imaging has been done with a 6-inch APO and a webcam (or webcam-frame-size firewirecam). So, your mileage may vary.

But a good many of my imaging buddies who do planetary work have similar numbers.

You need enough frames to get a good signal to noise ratio, but not so many as to court rotation blur. If the target is not bright enough, then using too much focal length enhancement will be a bad thing, inducing noise in the image if you must overcorrect with camera settings. If you make your exposures longer to accommodate a dimmer target, then there is a maximum frame rate imposed by the length of each frame (you can't shoot 1/15th-second exposures at 30 fps, for example).

Of the above targets, Mars is atypical: it is quite bright, but quite small, and the detail is very fine (there is little gross detail), and it has a slow rotation rate compared to Jupiter or Saturn. So, you can take the results from several AVI files instead of just one very long one.

Also, please notice that my color imaging is one-shot. If you use RGB imaging and must make separate passes through filters, then your overall AVI time must be held to just a few minutes with Saturn or Jupiter (to avoid rotation blur). In such a case you may be better off with a high frame rate since you get more frames to choose from for your final stack.

It's important to note there is no one-size-fits-all answer here: these parameters are a trade-off and you must often balance them against one another to get the best result.

TeleNoob:

Hi guys, is there a good codec that you could recommend? So far I have just used the spc900 with its own drivers, and QCFocus as the "front end" to make avi's.

With the SPC900 and Win XP I use the standard Philips VRecord software, but with Vista I use K3CCD. In either case I don't mess with different codecs.

With the DMK and DBK cameras I have 5 different codecs to choose from, depending on the video mode. I have experimented with several of them but find the standard ICCapture installation produces the best results on planets.

My experience has been that the ICCapture drivers allow me to range from 1.75 fps to 60 fps on lunar and planetary targets, but I generally stay between 5 fps and 15 fps for the most noise-free unprocessed images. When the seeing is softer and I just "must" image (e.g., to catch a Jupiter satellite transit), then I use up to 30 fps.

For solar imaging, I've gone as high as 60 fps to help with avoiding seeing turbulence. No matter which codec I choose from the ICCapture menu, I get a good deal of noise at that frame rate, but with solar it matters less because the noise gets lost in the continuum detail in the h-alpha image.

     Thanks everyone,

                  What is the best focusing method?  I've heard polaris, I've heard using a mask.  Is it best to focus under high magnification?  I'm using the SPC 900NC webcam.

          Also, those who use the SPC900, and use VLounge software, how do you change the file to an avi file.  So far, mine captures in .mpg format.  Do you change the white balance to outdoor, or leave it on auto.

                                                          Mike               

With Jupiter, I focus on one of its satellites, then adjust my camera settings for the planet (otherwise it'll overexpose) without readjusting focus.

With Saturn, I focus on the Cassini division.

With Mars, I focus on a conveniently-located double star, then adjust camera settings for Mars without readjusting focus.

If you have sufficient aperture (6 to 8 inches), you don't need to use a mask, although some people find it easier. A Hartmann mask or similar can be a big help with focusing on stars, but it doesn't help as much with planets because what you're after is fine detail and what you'd be focusing on instead is an overexposed image of the planet.

Your mileage may vary, but that's what I've found.

chipdatajeffB:

If you have sufficient aperture (6 to 8 inches), you don't need to use a mask,

I'll second that. I started with an 8" f/5 newt and Celestron NexImage webcam, using multipliers (barlows), before moving to the 10" cass (still using multipliers) with the two usb1 webcams (one mono, one RGB), followed by the usb2 Lumenera mono. I occasionally moved off to a nearby star for focus, but found it to be to time consuming, except for the first sequence. I also tried various masks.

Planetary features on Mars, features or moons for Jupiter, and Saturn allows for good focus. The planetary ball, or phase point allows for good focus on Venus (were, by the way, narrowband UV keeps operation down to 15fps). Stars help on Uranus and Neptune.

Spend a few sessions, and you'll personally experience what we have been discussing. You'll also arrive at the process that works best for you.

Robert