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MCinAZ

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About MCinAZ

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    Northern Arizona
  1. MCinAZ

    Securing Obs roof from inside

    That building had a small roof, so I needed only four wheels to support it. Each had its own lift mechanism. I chose that approach because the observatory was in the Sonoran Desert where we get a lot of dust storms in the summer. It all worked quite well in the end -- the lift mechanism proved to be entirely reliable and I had no worries about rain or dust intrusion regardless of weather conditions. I bought a small (15 l) compressor to operate the pneumatic cylinders. Provided that I remembered to close the valve on the tank immediately after opening or closing the week, it stored sufficient air for three to five nights of use before needed to be repressurized. I helped a friend build a similar observatory, also in the desert, but we took the more conventional approach and used fixed tracks, relatively small gaps and baffles built into the trim to minimize dust intrusion. While that building doesn't stay as clean through the summer as mine did, the owner finds the level of protection to be adequate. If I eventually build on my present property, I won't go with the lifts. There is much less airborne dust here in northern Arizona and I'm convinced that careful design and construction are sufficient. Apologies for straying from the thread topic.
  2. MCinAZ

    Securing Obs roof from inside

    Though somewhat manual, I agree that turnbuckles are a good solution. I've used these on the two conventional roll-off observatories I've built. I recommend installing them at a about a 30 degree angle to horizontal. If you add stop nuts to the pair at one end of the roof, you can adjust then fix the close position, then use the other pair to pull the roof securely into place at the end of the night. Avoid light duty alumin(i)um parts you might find at a mass merchandiser. Though not on an observatory roof, a friend of mine had one of these fail when the threads pulled out of the Al block. The turnbuckle was used to set polar axis elevation on his German equatorial mount and the failure nearly resulted in his custom 0.35 m astrograph going all the way to the ground.
  3. MCinAZ

    Securing Obs roof from inside

    My decidedly low-tech yet effective approach. I should note that the building incorporated pneumatic lifts so that when closed the perimeter of the roof rested on a foam seal. The C-clamps, one on each side, were only needed to keep the roof from lifting as it could not roll when lowered. We saw winds one night in excess of 110 kph and everything stayed where it belonged. It was my intention to find something similar to the latches Gina suggested but the C-clamps worked so well that I never pursued the notion. And now that the observatory has been decommissioned, I have a nice set of clamps for my workshop. If I still had a workshop. :-(
  4. MCinAZ

    JamesF's observatory build

    How do you attach the OSB to the roof frame? Will you be using self-tapping screws driven in from the top, screws coming through holes in the framing from the bottom, or something else entirely?
  5. MCinAZ

    Software for mount exercises...

    There's no need to go through the ASCOM interface at all. You can simply send serial commands directly to the mount. I've done this many times with both Gemini and A-P mount controllers as well as my Optec focuser using only a modem control program. I've also got scripts linked to buttons on my desktop which will send Park Home and Park CWD commands to my G11. An open-loop sequence script would be a trivial exercise in the Linux environment that I use, while closing the loop by reading status back from the mount would add only a bit more complexity. I presume that should be the case in Windows as well, though I wouldn't have the smallest idea as to how to go about writing one.
  6. MCinAZ

    Astrometry.net local (SGP) doesnt solve ??

    While I have no experience with SGP, I have solved a lot of images using both Nova (astrometry.net web based tool) and PlateSolve 3. PlateSolve is usually somewhat better at blind solving fields (no user-supplied detail regarding coordinates or image scale) and can often solve fields which Nova cannot even when very specific detail is provided. Unless things have changed recently with Nova, Dave Rowe's plate solution algorithm is clearly better. That said, there are some circumstances where PlateSolve fails to solve a field even given the exact center coordinates and image scale. This typically occurs only when a very small (< 1 arcmin) field of view is involved or very few stars are present in the image. I haven't used PlateSolve 2 so I don't know how it compares to PlateSolve 3. If you're using a planetary camera in long focal length optical path, plate solution may not be reliable, particularly where sparse fields are involved. There also seems to be a point where taking longer exposures to bring out fainter stars does little to improve the odds of a successful solution. I suspect this is due to the limiting magnitude of reference catalog data, which appears to be somewhere are 11 or 12 for both Nova and PlateSolve 3.
  7. MCinAZ

    ITMA - oacapture 1.2.0

    As it happens, I've spent the past two nights in the observatory now that it's cool enough to use it again for a few months. The new release of oaCapture came at a very opportune time, as I have used 1.1.0 extensively the past two nights. After installing the Ubuntu 14.04 Debian package on my Mint 17.3 machine, I had to take if for a spin since the sky is again clear here in the Sonoran Desert tonight. The ROI controls are much more straightforward (even if the "Use ROI" button appears now to be extraneous :-) and it's good to see the EXPTIME record in FITS headers, as this saves me a post-processing step. Having corresponded with James extensively over the past couple of years, I know that he has put a tremendous amount of time and effort into oaCapture. All of us who use his software owe him a debt of gratitude for taking on a very substantial task and staying with it over a long period of time. -- Mike --
  8. You can certainly use PS2 stand-alone. I would think in most cases it is more useful to use it as part of a tool chain, and that appears to be possible as well. Another alternative is the astrometry.net tools, either on-line or installed locally. Most of the time, the results are essentially identical, however I've found some particular cases (very small or very crowded fields) in which PS3 could determine a solution where astrometry.net could not. I haven't performed tests to see how well PS2 does in such situations.
  9. MCinAZ

    Free CAD Software recommendations

    I've found QCad to be a good option for 2D work. It takes a bit of time to become proficient, however once you learn how to use it, it offers a lot of capabilities.
  10. MCinAZ

    SGP and PlateSolve2

    After installing catalog data, I found that the M81+M82 and pacman images solved using PlateSolve-3.48 without issue. The other two solved after I manually entered approximate image dimensions. Curiously, when the pacman image is loaded, the image size dialog boxes are populated with approximately correct values. This is not the case with any of the other three files. Looking at your FITS headers, I don't see any obvious reason why the program behaves as it does.
  11. MCinAZ

    SGP and PlateSolve2

    Sky coverage should not be an issue. I've downloaded your files, however I've learned that my current installation of PS3 does not include catalog data. I have those files at home, but won't be able to install them until Monday. I note a slight discrepancy between the center coordinates in your FITS headers and those reported by Astrometry.net. This may be enough to confuse PS2. You might attempt a solution after clearing the coordinates loaded from the FITS headers. Don't know if that will remedy the issue, but its worth a try.
  12. MCinAZ

    SGP and PlateSolve2

    How much sky area do your images cover? If you could post an image at each scale, I could try solving them with a later revision of PlateSolve, so see if perhaps the algorithm has been improved.
  13. MCinAZ

    Capturing software

    As a couple of previous posters have noted, an intervalometer may be all that you need given your description. The model referenced in laser_jock99's message allows you to specify an initial delay, exposure duration, interval and number of frames. There are different models for different classes of cameras, though for the Canon line the only difference is the connector which attaches to the camera body. Exposure duration has a timing resolution of one second and matters only if you set the camera for bulb mode. Otherwise, the camera's exposure setting is used. You will probably want to operate the camera in program or manual mode for astronomical work. One point to note is that the interval is from start of one exposure to the next, so you need to make it slightly longer than the total time required to capture an image. This includes dark frame subtraction if enabled plus time to store the image to flash. Too short and the camera will not be ready to start the next exposure, so your frame rate will drop in half. For my Canon cameras, I generally make the interval about 2x + 3 seconds longer than the exposure time at minimum. Also, you will probably want to disable auto focus in almost all instances. -- Mike --
  14. MCinAZ

    Autoguiding on Linux with Opticstar PX125C

    There doesn't appear to be any Linux support for this camera listed on the website. Unless the manufacturer either provides a driver or releases sufficient information for the open source community to develop one independently, it's unlikely that you will be able to use it with any existing software. You may be able to guide using Windows software in a virtual machine if you have an available license. I found good success running PHD Guiding in Windows 7 under VirtualBox, however I was completely frustrated in all attempts to communicate with an SBIG camera in the same environment.
  15. MCinAZ

    oacapture 1.0.0

    And it does, however there are a few additional record types that could be added. More on that later, except to note that including EXPTIME would be a simple, obvious enhancement. It might even help prevent someone from inadvertently deleting all of the DATE-OBS records from a series of FITS images showing an asteroidal occultation because he had a bug in his post-processing script. Not that I've done such a thing. This week.
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