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.



New Members
  • Content Count

  • Joined

  • Last visited

Community Reputation

5 Neutral

About 1DegreeN

  • Rank

Profile Information

  • Gender
  • Location
  1. I and others have used Sharpcap polar alignment with Polemaster as the camera - that's something like a 12 degree FOV. But to use Sharpcap with a very small FOV such as you would have on the imaging camera it may need more, fainter, stars in its database in order to plate solve. Since it can currently plate solve (the brighter stars) within 7 degrees of NCP that could be a lot of stars to add.
  2. The resolution of the PM is 30 arc seconds per pixel so you would have to be lucky to get a more accurate PA than that. By contrast, if you were using e.g. a typical 50mm or 60mm guidescope with a QHY5 guidecam (same camera that is used in the PM), the resolution is around 3 to 4 arcsecs per pixel and so using Sharpcap with this combination is potentially 10 times more accurate. You can work out how exact your PA needs to be for your imaging camera and longest sub length. E.g. for your Esprit 100 with ASI1600, a PA error of 30 arcsecs and 10 minute subs gives a drift of around just 1 pixel.
  3. Hi Shawn I have a very similar setup to yours - an AZ EQ6-GT mount (belt driven, like your EQ6R Pro and possibly the same motors etc.), a 60/280 guidescope with a qhy5L camera giving a scale of 2.8 arcsec per pixel. Is your quoted RMS in arcsecs or pixels? If it is in arcsecs then I have no advice for you because that is as good as anything I've achieved. If its in pixels then maybe I am doing better and getting rms around 0.3 to 0.4 pixels which is around 1 arcsec. The PHD2 developers have recommendations for EQASCOM (EQMOD) settings to use with PHD2 - here: https://github.com/OpenPHDGuiding/phd2/wiki/EQASCOM-Settings I've followed those and use a guide speed of 0.9x I'm using short exposures for guiding - just 1s, or even 0.5s. I set minmo on both axes up to 0.25 (the guiding assistant usually recommends around 0.21) and did that after monitoring with guide output disabled and reckoning the amplitude of seeing was around 1.5 arcsec i.e. 0.5 pixel. Settings for aggression and hysteresis are the defaults. My mount, the AZ EQ6-GT, had an issue with the initial firmware release for the motor controllers and this caused frequent spikes in RA guiding. A firmware update resolved that. Your EQ6R Pro is a newer model but it may be using the same motor controllers. If it is, hopefully it already has the latest motor controller firmware but it is worth checking (via the handset) that this is the case. The biggest improvement to my guiding performance came from cable management. It took a few iterations but I'm reasonably confident that I have that under control now. cheers John
  4. Hi David Are you sure that you have the backfocus correct? The Flat6AII's backfocus of 54.8mm is from the wide rear flange where a T-mount would be up against, but you are connecting via the internal M48 thread and by my measurement the flange for that threaded connection sticks out by 5mm so the backfocus becomes 49.8mm. Also, you have to add (not subtract) 1/3rd of the filter width so the backfocus you want to achieve is then around 50.8mm. The components you list come to 53.8mm so you could be 3mm over. I've got the Flat6A II on my Zenithstar 103 and am very happy with the results. I haven't used CCD Inspector but visually the images are good with just very slight coma remaining at the corners of my APC-C size frame and PixInsight's FWHMEccentricity script confirms this. cheers John
  5. I have a problem with the RA belt on my AZ-EQ6GT where the teeth are coming off the belt. I opened the housing to find a fine yellow/green dust coating the bottom - this being material from the belt. One tooth was completely gone and others were on their way. I've never done any adjustments on the mount before and have no idea what caused this. I guess I may have had the RA clutch tightened too much at one point, that's the only thing I can think of. Anyway, thanks to the very helpful info in this thread I have a replacement belt on its way.
  6. I have the Canon 400 f5.6L and it is a sharp lens; if you have any interest in e.g. nature photography then it is a good dual purpose option. I have used mine for astrophotography with both DSLR and cooled CMOS. However if your interest is purely astrophotography then I would recommend the scope instead primarily because a) it will be easier to achieve optimum focus, b) you can attach a motorized focuser later and c) you can avoid a T-mount connection when attaching the scope to your ASI1600. I've just got a WO ZS103 and will be using that instead of the 400 for astrophotography from now on. I'm keeping the 400 for birding although I would much prefer a 100-400 Mk2! Don't forget to budget for the Flat61 flattener - you may need that to get a flat image over your ASI1600 and 550D sensors.
  7. Cyclops Optics have custom adapters to connect Nikon lenses to the 163c - https://www.cyclopsoptics.com/cyclops-adapter/cyclops-optics-blade-n-camera-lens-adapter-nikon/ I have their adapter for mounting Canon lenses on the 163M and the quality is very good. I use step down rings to reduce the effective aperture of my Canon lenses and avoid the diffraction spikes that the lens' iris blades introduce.
  8. As you've probably discovered, you can leave the Polemaster app running and it will continue to monitor the accuracy of your polar alignment. I think that's useful for a lightweight mount such as the SA, its very easy to shift the alignment when your acquiring your target, framing and focusing. I use the Polemaster with an Astrotrac and even though I think my setup is relatively sturdy and well balanced I still sometimes see a small shift out of alignment after moving the camera on to the target.
  9. It is possible to wind out the Astrotrac quickly, at its rewind speed. I can't remember where I got this from, probably from SGL, but according to Richard Taylor (Astrotrac founder): "If you hold down the track button whilst powering up, the TT320 will give 3 beeps in quick sucession BEEP, BEEP-BEEP. If you press track the drive arms will open about an inch, as normal, and stop in the ready to track position. Press track again, and the drive arms will open all the way out at rewind speed with the LED flashing blue. When you have finished cleaning, press the rewind button to close the drive arms"
  10. I have the HiTecAstro EQDIR cable and installed the PL2303 version of the Prolific driver (from the HiTecAstro website) back in September 2015, on my Windows 10 laptop. Still working OK and I have applied all Windows updates.
  11. Hi Peter I have the newer Astrotrac model, the TT320X-AG with the ST4 port for guiding, and I use their TW3100 wedge and the TH3010 equatorial head. I usually image with a Canon 700D and 400mm lens - similar in weight and size to the small refractor set up you are considering. Is your Astrotrac accurate enough? It should be, if it is still in spec. If it is not tracking accurately I believe you can return it to Astrotrac for servicing and re-calibration at a quite reasonable cost. Will you need to guide? Maybe. If your polar alignment is poor or there is any flex in your setup or if the Astrotrac's tracking is inaccurate then guiding can compensate for these up to a point. Polar alignment errors and flex will cause declination drift and guiding will not help with that. I use guiding myself but only because I want to dither between subs. What I would suggest is that you first get yourself a QHY Polemaster and perfect your polar alignment. You will soon find out whether your existing wedge is good enough to achieve an accurate PA - if its not then you could get the Astrotrac wedge which has fine alt and az adjustment controls. Once you have nailed the polar alignment you could do some long test shots with your SLR to determine if your Astrotrac is still tracking accurately.
  12. Yes I am guiding the Astrotrac but only because I want to dither my frames. I'm imaging with a DSLR (modified 700D) and frequently suffered from the dreaded "rain noise" or "walking noise" and dithering is the only way I've found to avoid it. Of course the Astrotrac can only be guided in RA so PHD cannot correct any drift in the declination, and unless your polar alignment error is zero there will always be declination drift. I use BYEOS to manage the imaging session and control the dithering; in PHD I have to periodically reselect the guide star to reset the declination drift to zero which prevents the dither interval extending to BYEOS's 90 second timeout.
  13. I have the Polemaster mounted in the Astrotrac's polarscope arm, using the adapter from Cyclops Optics. In the setup phase of the PM's procedure, when you rotate the PM (i.e. the polarscope arm) back to the origin and check that your chosen star follows the green circle, the star clearly deviates from the circle between detents but at the detents it is bang on the circle. I use PHD to guide (and dither) my imaging camera so I can judge the accuracy of the polar alignment from the amount of drift in the declination. On Tuesday night and again on Wednesday I was getting approx 4 arc seconds of dec drift in 10 minutes which is about 2 pixels on my imaging camera. If your polarscope arm is not sufficiently accurately aligned with the RA axis, this should become apparent after you do your alignment and then continue monitoring the pole via the PM application.
  14. +1 for plate solving. I have an Astrotrac and use an RDF to get roughly on target and then Astrotortilla (via BYEOS) to plate solve and iterate towards the final RA and Dec. This eliminates the guesswork, most of the frustration and the crick in the neck from using the RDF. You need to be able to make quite fine adjustments in RA and Dec so make sure everything is balanced carefully.
  15. I have an example that I think demonstrates the benefits of dithering. Back in January I took this image of the Orion nebula, using 30x2minute frames. This was the first time I had tried guiding (I was using an Astrotrac mount). M42, Horsehead and Flame by John Sim, on Flickr Two nights later I tried again, with dithering. I only managed 24 frames this time. All the gear was the same on both nights, sky conditions were similar and the only differences were 6 fewer frames and dithering between frames. I was pleasantly surprised, gobsmacked in fact, at the extra detail revealed: M42, Horsehead and Flame - with dithering by John Sim, on Flickr
  • Create New...

Important Information

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