What do you think of background of my Ha and Sii master frames? Are the blotches actually Ha and Sii? I can't say I've seen similar in other images of M76. Or is my Aluma 47-10 just that much more sensitive? My Oiii filter background is very even.
The 47-10 is the most sensitive "affordable" CCD on the planet; The QE curve is insanely good. e.g. between about 87 and 94% in the wavelengths of interest. Almost single photon counting. Do you have any original raw FITS frames from MaxIm? I can't do much with these as PixInsight trashed the science data. Here's a NOIR lab image that doesnt cover as wide a field. https://noirlab.edu/public/images/noao-m76-kpno-0-9-meter/ You can see stuff off the sides of the "butterfly wings". There a lot of detail in this Ha image from the Canaries: https://www.astrobin.com/391294/?q=m76 In these samples, you can see a lot of extra stuff in Halpha that does not show up on other folks images. Stuff shot with a 16803 or most Sony sensors just won't show it unless you have a huge scope - the QE is just not there. You can always check: - compare/subtract other images taken to see if the blotches are positional - eg specific to the filter, and then they'd be in the same place. - if you have a bad frame in data set - go hunt for internal reflections - residual image effects - ghost images from charge remaining from pixels that got saturated @Doug may have some additional comments
Hi Colin, here are single fits files of my Oiii and Ha data. I actually have two sets of narrowband filters, when I originally shot M76 a couple weeks ago I was suspicious so this past weekend I swapped the filters out but to my surprise the data looked the same so it would seem to verify the data is good. Just getting my feet wet with the new chip trying to get an idea of how long to my my exposures.
To draw any conclusions I'd really need a full set of images, plus calibration frames, in one of the filter bands.
https://www.dropbox.com/scl/fo/mq1uy5jipovrbrkjsrfpw/h?dl=0&rlkey=lmqfuklhh4h580ousl66kj1ol https://www.dropbox.com/scl/fo/2qblbwlr4vi6svf1ya1h1/h?dl=0&rlkey=wfty7yjtk1ihopsgk73663b1r https://www.dropbox.com/scl/fo/xknqfhbxodyob1e8forjg/h?dl=0&rlkey=8dz9bkvkvfris1osjhsz27a0d https://www.dropbox.com/scl/fo/ker692h3w680zf9d9uph0/h?dl=0&rlkey=9ggihp642v0ut2ghbvai98dh5 Doug here is a link to a set of Ha Lights/Flats and 120s darks and bias frames.
The flat folder is full of .xisf files; I think that is some kind of proprietary Pixinsight format? I need FITS.
Sorry Doug, those were my calibrated flats. Yes, Pixinsight just to be different converts Fits files to their own format. Here's the link to the uncalibrated flats. https://www.dropbox.com/scl/fo/f6y98s8and4b70ew55na4/h?dl=0&rlkey=ck6soqg9vdshek8pvd8vytkf7
Here's what I got from processing your images in MaxIm DL. You can see that there is some faint nebulosity in the background. Blinking the individual images after calibration I can see that there's some stuff there... so I'm pretty sure it's real. On the other hand, your image has a lot of extra blobs. Most of "my" blobs show up in "your" image... but there's a whole bunch of them in your image that are NOT in mine. This makes me think something went wrong with your image processing. Maybe there were some misaligned images that got added in??? My image: Your image:
Doug, mystery solved. It looks like my data late January is suspect (Antlia 3nm) I stacked each session individually and the first set has all the extra blobs and the second set of data from last weekend using the Baader 3.5nm looks exactly the same as your stack. I'd say it's pretty impressive for all of 24 minutes of data!
