Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.


  • Content Count

  • Joined

  • Last visited

Community Reputation

3 Neutral

About shamantanthew

  • Rank
  1. Hi @StuartJPP, what 12v battery are you using to power the mount and hub? I take it it's the silver square on the ground... lithium ion? What size and many hours do you get out of it (powering mount, guide cam, USB hub, DSLR too(?))? Thanks!
  2. @StuartJPP Will the miniguidescope screw on to the PoleMaster camera? I already have the PoleMaster, but am wondering if I could pick up the miniguidescope like you have and use the two together--first to polar align with SharpCap, then to autoguide. Edit: nevermind, just clicked that the PoleMaster can't send the autoguide message to the mount
  3. Reviving this thread as I just had a thought... I've always been bothered how the TH3010 head clutches introduce some play/wobble into the system when released to swing the arm the 15-30 degrees required for the PoleMaster routine. It looks like it comes back right where it was, but pixels matter! An alternative for those of us not mounting the PoleMaster in the polar scope holder would be to have the Astrotrac wind itself along the length of its screw to do the swinging for the PoleMaster routine; however, the Astrotrac's too slow to do this in a reasonable amount of time, the fastest it can go is 1.5x sidereal rate (using a switch via RJ45-RJ12 at the autoguide port). But it must be capable of faster speeds (forward and reverse) because it's quite fast to spool through those first 10 seconds after starting the Astrotrac or when it comes time to rewind it. Anyone know if it's possible to make the Astrotrac speed forward the entire way through the length of the screw, not just the first little part?
  4. @StuartJPP, you use the QHY miniguidescope, correct? Have you run into any driver problems with using the QHY-5LII and the Polemaster at the same time (e.g., disconnects within PHD?). That is, assuming your use both at the same time. Someone on the Astrotrac yahoo group mentioned this was a problem for them but I couldn't find more reports of this on Google.
  5. I'm reporting back with bad news... I think I had the best beginner's luck in the world when I posted those screenshots from my first time out using the Polemaster and the Astrotrac because I have not been able to replicate that success. The last 3 times I've set up I've been limited to about 3 minute subs at 400mm with my 6D. I'm pretty confident the problem is the polar alignment. My guess would be too much flexure in the RA axis when the clutch is loosened to move the arm 30*, although when I return it to the "home" position the star I chose is typically on or very close to the circle that's drawn. Another theory is a balance issue, although I take care to balance every time I set up.
  6. I also used the PoleMaster on my Astrotrac and it worked great. I managed a 6 minute exposure at 400mm on my Canon 6D without significant trailing after my very first time using the PoleMaster... that's twice as long as I managed prior to the PoleMaster and using the polar scope (fairly well collimated polar scope but not collimated polar scope arm). I did start to see trailing at 7 minutes. This is an image from the handle of the Big Dipper at 54.8 degrees of DEC. Here's 100% crops from the center and the very corners: 400mm 6 min Astrotrac Polemaster by Shaman Tanthew, on Flickr Here's my homemade adapter at the end of the counterweight bar using approximately $5 worth of hardware store goodies: Astrotrac Polemaster Adapter by Shaman Tanthew, on Flickr As Stuart mentions, yes, loosening the RA clutch induces some tilt/instability while swinging the camera, but fortunately the TH3010 head seems machined well enough that tightening it back down brings it back to where it started.
  7. Thanks Themos, you are correct with regard to my resolution, and that's a good idea to shoot at a reduced resolution. As long as I don't forget to put it back!
  8. Very cool! I'd love to figure out a way to fashion an adapter to mount the Polemaster to the counterweight bar or at the end of the counterweight bar... I'm not looking to modify my TH3010 head yet! With the Polemaster I've been reading that you need to rotate along the RA axis and then eventually return it to where you started... how precise do you have to be when you return it? Does it have to go exactly back to where you started or just somewhere in the neighborhood?
  9. And quick update: I have Nova solves working again for PPA (on my laptop now, not just my desktop)... had to google for the Visual C++ 9.0 and Microsoft's site had a download for it for Anaconda 2.7 installations... installed ujson and now it's working great!
  10. I had a moderately productive and successful test run last night (finally). I use PPA with my Astrotrac and the astrotrac wedge, head, and pier (the whole getup). I aligned it with the polar scope as best I could then took my vertical and horizontal shots. Unfortunately my local solves were not working quite as well as they had been with my previous data. I had to fiddle with the sigma value quite a bit... my default of 20 that had worked with my old data was sometimes too much and sometimes too little, but it always fairly close. If the solve failed with sigma 20 then I found I could get it to work at 15, and other times at 25. Unfortunately I think this part just requires trial and error as exposures are always going to be a little different (I had half the moon to contend with last night compared to last time when it was a new moon). BUT sometimes it would solve in 20 seconds, I'd check for improvement, move the axis literally just a smidge in one direction, take another shot, and then it would fail to solve despite using the same exposure settings! The field barely changed and it failed to solve when it had no problem on the shot before! Regardless, I was able to make multiple iterations to get it dialed in closer and closer, which is exactly what I needed. In the future I'm going to try to keep the histogram in the same spot as what has worked for previous sigma values. Plus, my Nova solves weren't working because of ujson!!! I thought I had fixed that earlier but now I'm thinking maybe I only fixed it on my desktop during my testing and not my laptop. I even updated pip while out in the field last night (yay for cellphones and tethering) and tried updating ujson but it still didn't work! It errors out saying Microsoft Visual C++ 9.0 is required... I'll look into figuring that out later. The best I could get was about 4 arcminutes. If my local solves were working faster without requiring me to adjust sigma every now and then I would have dialed it in further, but things were taking too long (my field laptop is ancient, it turns 10 years old this June but typically plate solves these for me within 30 seconds). Still, if it fails to solve then that means adjusting sigma up, adjusting sigma down, and sometimes still not getting a solve. With this polar alignment I was able to take the following 4 minute exposure of M101 (very faint) from my red/white zone neighborhood with the Canon 6D and 400mm f/5.6. This is a 100% crop from the upper left 1/3 of the full frame: A little trailing, but not bad, and certainly the best I've ever been able to achieve at 400mm and 4 minutes.
  11. Forecast calls for a clear but breezy night... Looking forward to giving PPA another shot now that I have local solves working!
  12. Hey Daz, I ran into the same problem with Nova and the ujson error. This occurred despite me installing the Anaconda 2.7 version (I think I installed x64 and not x86, not sure if it matters though). I fixed this by following Themos' instructions on page 4 of this thread: open a cmd window, change your directory to your python installation, e.g. "cd c:\users\mathe\anaconda2" in my case, then use the command "pip install ujson"... In my case it said I had to update pip so I followed the commands to do that, then I re-entered the command pip install ujson and it installed ujson at that point. Restarted ppa.py and now Nova works.
  13. I may have stumbled across the "golden setting," so to speak... downscaling. I set downsclaing to 2 instead of 0 and now it solves in 15 seconds. Gonna keep playing with this.
  14. Thanks Themos! I wonder if you using the smaller resolution files is what's causing our different results. Here's a link to the full-size files: vertical: https://onedrive.live.com/redir?resid=2ECF5A87B0942D0D!14831&authkey=!AFDpiv7s9DvGKbc&v=3&ithint=photo%2cJPG horizontal: https://onedrive.live.com/redir?resid=2ECF5A87B0942D0D!14832&authkey=!AJ6-B4kkii2EkgU&v=3&ithint=photo%2cJPG And PPA gives me the following polar alignment error (using the full size files and Nova to solve):
  15. This software is great! I had a chance to test it out last week in the field but my local solves weren't working fast enough. I need help getting AstroTortilla to do local solves faster! The Nova website is fairly fast, around 10 seconds each, but I won't always have internet access out in the field. Sometimes AstroTortilla won't solve at all depending on my settings. Vertical: http://img.photobucket.com/albums/v245/Nathan49456/IMG_3891.jpg Horizontal: http://img.photobucket.com/albums/v245/Nathan49456/IMG_3890.jpg I'm using a Canon 6D with a 400 mm f/5.6 lens which makes for 3.45 arcsec per pixel. I'm using the following AstroTortilla settings and indices: Astrometry.net uses the 4112 and 4113 indices to solve these two images, so I when I move all the others out of the folder and force AT to just use these two indices it still fails to solve!
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.