Possible to eliminate Newton Rings?
Posted 06 March 2013 - 11:17 AM
Oddly enough, I don't see any sort of artifacts when not using the powermate.
Posted 06 March 2013 - 11:42 AM
In certain cases with imagers that use certain Micron or Aptina sensors, the rings are produced within the sensor itself (as I understand it). I have this problem when attempting to use the orion SSAG for imaging h-alpha. Unfortunately no amount of axial tilt can fix that.
Posted 06 March 2013 - 03:01 PM
Posted 06 March 2013 - 03:13 PM
Posted 06 March 2013 - 03:19 PM
Posted 06 March 2013 - 06:06 PM
Posted 06 March 2013 - 09:59 PM
I would think if it were the sensor, that I would see them when using native focal lengths, no? As far as the issue with the 2.5X powermate, that was in internal reflection and I'm not seeing that issue with mine. I've tried a normal 2X barlow and still got the rings.
Correct, my rings are present with or without barlow. They are certainly annoying.
Posted 07 March 2013 - 06:44 AM
I worry about using the Teleskop tilt adapter. It seems like with all the adapters that are needed to make it work might take up too much focal range to allow focus when using the powermate. That'd kind of defeat the purpose.
Posted 07 March 2013 - 02:32 PM
Posted 07 March 2013 - 10:49 PM
Posted 07 March 2013 - 10:52 PM
Posted 08 March 2013 - 06:56 PM
Any pictures? At various focal lengths... That will help us diagnose you the best course of action...
Finally got out today for a bit, although the seeing was lousy.
Here is a detail that was taken with the Powermate:
And, here is a two panel full disk mosaic:
Posted 08 March 2013 - 06:58 PM
Try a lens cap, works every time. But seriously, the problem may be in the camera, I'm sorry to say. This sort of fringing occurs in CCDs and is more pronounced with longer (red and IR) wavelengths. Some chip designs are worse than others and even with the same design there is variation from one chip to the next. If that's the case then tilting the camera is your best option.
I know that CMOS sensors tend to be worse for issues like this. The e2v sensor in the Flea was supposed to be not as susceptible. I guess that's not quite right. I may start looking for a different cam with a CCD, at least for solar. The Flea should still be good for lunar and planetary.
Posted 09 March 2013 - 11:06 AM
Posted 10 March 2013 - 07:40 AM
How fast should the movement be? I have a CGEM, so are we talking Rate 1 speed?
Posted 10 March 2013 - 08:12 AM
Posted 10 March 2013 - 11:01 AM
No, registax should automatically compensate for it. Often the best way to get the drift you need is just to do a poor polar alignment, it will naturally drift for you then...
Being as I'm just plopping the thing on the patio and letting it rip, that shouldn't be difficult.