Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 04/07/2020 - 15:58
My LY Lib images, mentioned in another thread, fainter stars are surrounded by halos. Max ADU of brighter stars is over 18000 ADU. I am not sure what the full well capacity of the camera might be and puzzle over the halos. Is there anyone familiar with BSM NM2's configurationwith whom I can share some images for evaluation?
Thanks, Ed
Ed,
I'm seeing the same faint halos. I assume these are chromatic aberration artifacts from the field corrector optics. i think the measuring aperture/gap/sky background settings can be arranged to leave most of this in the gap, so I don't think this would be a significant photometry problem.
My first images from NM2 (of R CrB) were over exposed, at least for the target. No surprises there. It may take a couple of interations to get the exposures right for your star with the new telescope. (BTW, the linearity limit is set at 62K ADU's in the telescope profile in VPhot.)
Based on the SNR's and ADU's in the first set of NM2 images, I guessed at new settings. George put them into the system, and they worked out fine. Thanks again, George.
I think these new telescopes will be a tremendous improvement (if we ever get the transforms). I have hundreds of images (before stacking) of R CrB from NM2 waiting to be reduced. ...just need the transforms.
Phil