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.



Advanced Members
  • Content Count

  • Joined

  • Last visited

  • Days Won


moise212 last won the day on September 12

moise212 had the most liked content!

Community Reputation

1,149 Excellent

About moise212

  • Rank
    Proto Star

Profile Information

  • Gender
  • Location
    Romania, 45N
  1. Does the 46p have 2 tails now? I've only seen one until recently. This is just a quick integration, I did not spend too much tweaking the rejection parameters. And the colour calibration is probably way off.
  2. I don't find anything really benefiting from a ~240mm focal length, but too tight in a 200mm. Moneywise, in the same ball park, you can get a second hand Canon 70-200 F4 L. The results I saw at 200mm with the aperture wide opened were good enough. Not to mention the backfocus is much longer and the imaging circle has to cover a full frame sensor.
  3. moise212

    Iris nebula with Skywatcher 72ED

    Around 60mm is not perfect, but quite fine. Thank you! I can't get such results where I live either, but at a dark site... quite impressed too.
  4. moise212

    Iris nebula with Skywatcher 72ED

    Hi and thanks! I haven't had yet the time and drive to process this properly. It's still on the process queue, but with a lower priority. I used the dedicated reducer which is actually a reducer for the 80ED with an adapter. You need to increase the distance between the reducer and the sensor to about 60-62mm in order to get round stars towards the corners. More distance and you end up not reaching focus anymore. I measured the focal distance with the 0.85x reducer/flattener and a backfocus distance of ~60mm and it turned out to be ~375mm. With a non reducing flattener I got ~430mm.
  5. I plate solved an image taken with the ovl non reducing flattener. Focal length turned out at about 431-432mm. I can easily think of at least one other 72mm scope advertised at 432mm focal length.
  6. Can I consider the bad performance as fault? The mount was tracking bad, I sent it for servicing in order to be improved and now it's about the same as before. No sub arcsecond guiding, no minutes long unguided exposures with a short scope and no star trails. Many can expose longer with a Star Adventurer at 135mm focal length. The only felt improvement is at how the RA axis spins with the clutch disengaged and maybe also the backlash, but I don't care much about the backlash as I can always adjust it by myself.
  7. Thank you for the detailed explanation! I'll try to make a deal so I won't end up at a total loss.
  8. Thing is I don't know mostly anything about European legislation, I only know something that applies in Romania. If I send the mount back again, I'm afraid I won't receive any replies anymore and/or have no delivery date set. So I can end-up maybe receiving a bad performing mount again after 3 more months which would be a big waste of time. Moreover, as I received no evidence about how the mount performed at them, they can say that the mount is performing well when they receive it. What then?
  9. I ran another set of tests as the original ones were not really taken into account due to the polar error. So new ones. Same kind of results, of course. The image in the background is a 2 minutes exposure at 135mm focal length with a Canon 550D. According to Dave, if the mount tracks ~70" arcseconds, it's probably worse than an EQ3-2. However, as he doesn't really want to admit and he explains that the sudden deviations from the sidereal tracking are not important, only the mean drift over a long period, I'm not really convinced of either his intentions or of his knowledge. Am I protected by law to ask for a refund if the mount does not perform as claimed? I'm not really interested anymore to send the mount back as the way Dave treats me is kind of insulting. By the way, I asked many times for logs to see how the mount performed at them, but I only received replies that he will send them, of course I didn't receive any.
  10. Same thing with PecPrep. Dave explained me that he does a Jupiter test. If after a long while Jupiter is still in the frame, the mount is good, the RA tracks smooth. Basically, he manages to polar align well the mount and if the motors revolution speed is properly calibrated for the gear ratio, you're good to go, the mechanical error is small enough. Wow, just wow. This is not the kind of reply I wanted, but, unfortunately, is the kind of reply I expect after all the discussions. He tells me that it doesn't matter how much the RA tracking jumps, the drift over a long time running is relevant. If, after 30 minutes of tracking, the drift is 15 arcsec, it means that the drift is 0.5 arcsec/min. What happens meanwhile, if the tracking jumps ahead and beyond, it's completely irrelevant for the final result. So if I have a drift of 30" in less than 40 seconds, it is invisible in an image, because the average drift over a long period is very small if I polar align close to perfection. I don't even know how to argue with this. Does he take me for a fool?
  11. I haven't yet as yesterday it was late and I got angry quickly. Regardless if it's 50" peak to peak or 70", I don't care as long as it guides fine. But it doesn't and you can see the RA speed-up going ahead of the sidereal tracking by ~30" over 40s, in the opposite direction of drifting due to the polar error (you can see on the graphs that the RA line was going down overall). With that drift, with a Canon 550D (4.2um pixel size) and a 30mm focal length lens, I would get ~30"/pixel. That means that over 40s, a star would drift with one pixel. And that is in the opposite direction of my case of polar drift. So basically, with a perfect polar alignment, maybe I would be limited to 30s exposures with a ~24mm focal length lens, unguided. That is if I don't want any visible star trails. At 40mm, I would already see trails. At 400mm? Maybe 2s. I hope I didn't disable the logging recently, it is usually always enabled. I should be able to analyze them this evening.
  12. I will play the game and next time it will be clear, I will spend more time for alignment + drift align a few times, just to eliminate any possible reasons for excuses.
  13. I understand that you cannot measure exactly any error because I have the polar error larger than 14 arcmins, but still... You can see that the RA drift due to polar error moves the graph down (clear from the second picture above), though, the first wave up is at least 32" higher than lowest value, perhaps somewhere at 50". And that happened in less than 2 minutes. Or ~32" in ~40s according to the graph. I platesolved some images taken with the Esprit 80 and its focal length is ~415mm, not 400mm. That means that the reported 32" are actually 30.8". However, the blue line exceeds the boundaries a bit.
  14. Thanks! I already know how to adjust the gears, I stripped the mount several times and adjusted before sending it. The RA tracked erratically before and so it does now. I also balanced a bit east heavy and on DEC it was balanced with no bias in mind, but the DEC is stiffer so I couldn't asses if it was camera heavy or not. I have an EQ6-R and an EQ5 with tracking motors only + enhanced controller and both perform better than the AZ-EQ5. Unless there were some powerful gusts of wind that I did not feel + a big backlash on the RA axis that I also didn't feel, I cannot see how the RA can track now slower, a few moments later much faster then slower again and blame the polar alignment for this. I had the mount for more than 2 years before and this is how it used to perform. I didn't know what good or bad meant until I put tracking motors and guiding on the EQ5. It seems that I have to align and setup to perfection before they take into account any tests, even if the errors are not related to polar misalignment. More time wasted.
  15. The mount rotates with the clutch disengaged much smoother now, indeed, on the RA axis at least. Really. So it made balancing a breeze.

Important Information

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