Rodd

Thanks Olly. Regarding the alignment, the software says it can’t find enough putative star matches. So even if I use a broadband filter as a master to align all subs, the Ha subs fail because PI can’t “see” enough stars. I managed to get them to align, but I had to use settings that may compromise the accuracy. It didn’t seem to. But the PI alignment tool doesn’t seem to be designed for data that is less than optimal. I have had this trouble before with Ha.

I would very much like to get a large pixel sensor for the C11Edge....12 um. A pixel size that would put the pixel scale around 1.6 or so. With my sky, I can't really see a difference between .4"/px and 1.5"/pix , hence the reason I can bin 3 and not see a resolution reduction. I guess there is an argument to be made that there is no difference between a large pixel and a bin 3 smaller pixel. Others would no doubt be much better able to disect this question

That is interesting. At similar focal ratios the larger aperture should provide faster signal building for sure. Smaller pixels are less sensitive. I don’t realize they impacted signal that much

Interesting. I guess the aperture difference between my refractors and the 11” Edge overcomes the optical design differences because my fwhm in the C11 is always smaller than the refractors. Thank you for the info!

I am not sure if my Ha data is "normal". 5 sec subs reveal no stars to use for framing and alignment. Nor do 10 sec subs. I have to take 30 sec subs to achieve this. This seems odd to me. Does anyone else have this issue (I am shooting at 1960 mm. I do not notice this when using refractors and a smaller focal length). This leads to trouble registering the subs. I had to adjust PIs star alignment parameters very aggressively to register the subs--even when at least 20-30 stars are visible in each sub. This is a 72 300 sec subs stack. 6 hours. I plan on collecting a bunch more to bring out the faint Ha knots along the outer rim of the galactic disc, which are just faintly visible on my processing computer, which tends to be a bit lighter than most screens. So the other question is, can you see the faint outer band of Ha regions? Much of the Ha haze between definite Ha structures in the core will be removed when I clean the stack of unwanted red signal. But that can't be done until I have an RGB image from which to extract a red channel (not sure if it can be done using a red stack alone. That is a question I have been pondering for some time)--so the third question. C11Edge with .7x reducer and ASI 1600: 72 300 sec - Bin 1 Bin-2

Well, I couldn't resist. I reprocessed the image to what I believe to be better effect. There are still issues with the background, but I think the faint extensions are better defined and have more color (I did not bump saturation in the extensions).

Sounds interesting. I think it would still be better to get good luminance data. It sounds like there is lots of opportunity to screw up with processing. I tell you though, with RC Astro blur exterminator, small stars are not as critical.

Your right. At the time I had not integrated the data and I was not very familiar with the target. I probably should have kept going. However, It would be tricky to only use the luminance in the extensions—at least for me…using PI. I do think the rest of the image will benefit from a good luminance. I hope to be able to confirm this!

I agree. I did collect a few lum subs--with the FSQ luminance blows out the sensor pretty fast--I can never use the same exposure time as the other filters. But I was able to take 120 sec lum subs and they looked good--the FWHM was too high for my liking though, so I packed it in for the night. Seeing degraded. For the other filters and 1/2 the blue FWHM was around 2.2. Not bad. But it climbed to over 3.5 by the time I got to Lum. Shame. But at least I know it will be possible

Yeah, maybe the first version is better

Thanks Olly.

Thanks Guys--here is a reprocessed image--Bin 2. More attention to color balance in background.

Thanks Alan. I am happy with the resolution--seeing was unusually decent. Transparency was the issue I think. You know those nights where you struggle to make out the constellation?

Thanks Wim. I am underwhelmed. I had an exceedingly rare 4 nights of clear sky with decent seeing (except for the second half of the blue channel). I had high hopes. I guess transparency was its usual poor self. If I didn't know better I would think I picked up a bunch of IFN (NOT!). Its funny, but the stacks look good. I couldn't wait to process the data. I have noticed this before, however--combined data can look worse than the associated stacks. Maybe a proper luminance will help. two nights--8-10 hours. I am in for a week of rain now.

RGB version with synthetic luminance. Seeing dropped off a cliff during the blue channel. The strangest think about LP is that even when the background is clipped, it is still visible. If I take this one any further it will be clipped. I badly need a good luminance - a real luminance C11Edge with .7x reducer and SI 1600. About 13.5 hours. Bin2

I t has taken me a long time to get back to it. I finally decided to go with the C11Edge for galaxies over the TOA 130. It is, after all, the reason I bought it. I am glad I was able to quell refractor fever. Normally, it is a decent countermeasure to aperture fever, but in this case, I think it was the right decision to go with aperture. It has been cloudy almost perpetually, with clear nights that are forecasted deteriorating into cloud banks with the coming of darkness. Fortunately, I used the OAG from the FSQ to the C11 instead of the Celestron AOG. This meant that the guide cam was perfectly focused immediately. I didn't have to touch the guide cam focus. Another benefit in using the ASKR OAG is it is much thinner, so my sensor is actually very close to 146.5 mm from the objective--which is the design spec. I decided to start with NGC 3218, which is one of my favorite galaxies. I had shot this same target, same filter same camera same scope last year but could not complete it due to seasonal progression. I tried combining the data from last year and noticed something I had not seen before--the stars had spike artifacts. I am not sure if this was because of faulty distance, or wind, but the image is much better over all without the old data. Shame to, because instead of 7.8 hours, I now only have 2.8 hours. The FWHM was slightly better in the old data (2.2 vs 2.6), but I attribute that to 1/5 seeing and windy conditions. This time, I inspected all subs and found that about 20% had wind artifacts. I did not inspect last years data the same way and suspect it has wind artifacts as well. I only have the stack, so it is what it is. Anyway--here is my first data from the C11Edge with the sensor at the right distance. Its only 84 120 sec red subs, but it shows promise. Considering this image is bin 3, resolution was pretty decent. With bad seeing and wind, I think a FWHM of 2.6" is not too bad. My sky is poor--lots of LP and low transparency, so its hard to achieve a nice background without clipping. This stack has 2.8 hours. maybe I will collect more red for a 5 hour stack. 5/5/5/7 for 22 hours. I don't think this galaxy has appreciable Ha. If anybody knows otherwise, let me know and I will happily collect some C11Edge with .7x reducer and ASI 1600. Red: 84 120 sec, Bin3

Ic443 is the jellyfish. Are you referring to that? I think it’s the previous image on smugmug.

Wow--Love the framing and processing. You mention IC-443--is that close off the top border? I kind of expected more details in and around the Fox Fur due to the aperture. I am comparing to a 318 mm FL and pixel scale of 2.46"/pix. Maybe its due to broadband vs narrowband. That kind of makes sense.

Thanks Olly. The background always gives me trouble. I try to keep the numbers at .6 or .7, but due to LP, it is very hard to get it even. So it’s probably closer to .3-.4. I think RCs noise exterminator helps. I am getting a feel for it. How about this one. I lifted the black point slightly

I see. A matter of position. Yeah, .3-.5 is more like it. I have had pretty low factors. Probably depends on the signal strengths.

What is c. I use Ha-(r-Med (r))*.05..........I fiddle with the multiplier as needed. .05 may be the right number but it could be off by a factor of 10. What is the correction factor? Is this a new revision? I have not seen it before.

A bit of fine scale sharpening--maybe nearing the theoretical limit. Its quite noticeable.

The middle image looks almost like a SHO. Very nice. While I do like "natural palettes"--meaning RGB or NB that are made to mimic RGB (such as HOO), I am always thankful I captured SII when I decide to do it. Your middle image looks like SHO. Very nice. I just read a thread where it was opined that blue is unnecessary, because Lum. Using that logic, I suppose contains all of RGB and to get blue, one just has to subtract G and R from lum. I suppose this is true for each color. Not sure I am convinced. It makes sense, and certainly saves a night (or 2 or 3) of imaging if true.

Thanks S. In my sky, allot of integration is needed. Not so much for bright targets like galaxies--but for the background--and noise.

Wow--now that is a FOV! Nice orientation. What is the OIII emission near top? That looks like a potential decent target for longer focal lengths