jimjam11

@blinky interesting. Did you ever do anything about this? I just got a ZS73 and it is super sharp but I noticed the exact same phenomenon in stars...

No, normalised real and scientific notation. They are then directly comparable with the noise evaluation output...

I used this link: https://pixinsight.com/forum/index.php?topic=7388.0 Basically a combination of the Statistics process and Noise Evaluation script...

Whilst we went on a bit of a detour I think we have shown a couple of things: 1. The SNR improvement is measurable and visible. 2. The benefits of binning post acquisition massively outweigh the cons because it gives you choices; I see this in the same way I see RAW vs jpg with a dslr...

Thanks, That was relatively easy to do and produced the following numbers: No binning - SNR: 3.59, FWHM: 2.706px = 3.14" Bin2 before integration - SNR: 6.09, FWHM: 1.599 = 3.69" Bin2 after integration - SNR: 6.18, FWHM: 1.598 = 3.69" SiftBin - SNR: 6.27, FWHM: 1.572 = 3.63" It definitely works, it gave tighter stars and a better SNR! Was this the tool you used to downsize your example image higher up without any resampling?

Never used it before. Would it be simple to run over a set of files and produce the sub-divided subs? Using auto, never even looked that far down the star alignment process before! Specifying Lanczos-3 I get a FWHM in the integrated stack of 1.594px = 3.68"

Original sampling rate was 1.16" pp More research required to see if I can split bin! Is there another tool which does this easily?

Just ran an experiment on some of my IC1396 data. For a stack of 59x300s subs I get: No binning - SNR: 3.59, FWHM: 2.706px = 3.14" Bin2 before integration - SNR: 6.09, FWHM: 1.599 = 3.69" Bin2 after integration - SNR: 6.18, FWHM: 1.598 = 3.69" I got SNR by getting the AvgDev for each image as S, and the noise value from the NoiseEvaluation script as per this link Both of the binned images look cleaner but they are much less sharp bin2.fit NoBin.fit NoBin_int_Bin2.fit

There is an example here which can be easily modified to batch bin: http://pixinsight.com.ar/en/info/articles/23/batch-processing.html The only problem with this approach is if your image has WCS coordinates PI will raise an alert for every file that you need to dismiss! Edit: If you change the xisf file treatment you can get around this as well: https://pixinsight.com/forum/index.php?topic=11616.0

My understanding is that this is not optimal. There is limited benefit to binning cmos at capture time because there is no read noise gain. If you had excellent seeing but captured binned then you are effectively throwing away resolution (especially up at 2.8" pp). You also get more control of the binning by doing it post-capture. (You do of course gain in data volume by software binning but hard disks are cheap)

If that is typical then you are already pretty close? Assuming a guidescope your MnMo looks high, I would expect 0.2 or below with a typical 180mm focal length. Also not sure what a realistic expectation is for a heq5, I suspect around 1”...

Next time you are out, use the guidescope and run a new calibration. Once complete run the guiding assistant for 7+ mins and it will give you a wealth of information you can then act upon...

What is the problem you are trying to solve? It doesn’t matter what phd looks like as long as it is working. If you tell phd to auto select a guide star it will pick the best one so you don’t need to worry about them being too bright. A 50mm guidescope will easily be enough for 550mm with an asi1600...

Had one of these for a couple of days and I think this is the first piece of astro equipment I can use when it is cloudy and raining! I notice the app has a record function whereby it can write the data to a csv which could then be analysed. Has anyone ever done this as a way of measuring the number of clear hours we get per week/month etc? This seems like it could be very useful information???

I do similar, I use 76 for LRGB and 200 for narrowband. I get 30s L, 60s RGB and 300s for Narrowband. I then interleave the frames in SGPro so I capture LRGBL before a dither...

I love Clear Outside but I dont get the seeing predictions at all from this (7 timer) or meteoblue. According to this the seeing on Mauna Kea will be 60 on saturday, so poor- very poor and the same as central Edinburgh. Looking at a weather forecast for Mauna Kea gives a seeing predition of 0.5" for saturday so that seems rather spectacular; i highly doubt Edinburgh will have 0.5" seeing...

I dont think any of this matters. If you have either of these cameras they will not be the limiting factor; a million other things will... The asi1600 exposure tables on CN are a great resource, exposures should be surprisingly short in most conditions... https://www.cloudynights.com/topic/573886-sub-exposure-tables-for-asi-1600-and-maybe-qhy163/#

Agree its a great idea and I have been doing the same since last year, inspired by TAIC messier marathon video from 2018 M7 has a projected altitude of -2deg from my location so I wont be getting that in this lifetime...

If you are having trouble with focus/cooling you should be able to test this in the daytime and eliminate dss from the mix. Follow your normal routine focusing on something obvious in the daytime and take some images of that with/without cooling?

This was my first attempt at an SHO image and I am loving narrowband. SNR is so high compared to broadband in a light polluted area! SII - 6x5m + 23x7m Ha - 35x5m OIII - 27x5m All were gain 200 and -20C. I had hoped to get to 15-20hr and whilst the seeing was good there was lots of high cloud rolling across so I lost approx half of my subs. SGPro behaved impeccably pausing then resuming the sequence over the course of 2 nights whilst I was asleep...

Another update: I was desparate to buy a new OTA believing the mirror was the cause of my bloated FWHM measurements but I resisted and it would appear this was not the case. A few nights ago during some very calm weather I averaged 3.16" over the course of two nights, with a good number of frames < 2.5" and 1 frame at 1.89". Looking back at my original comments I think it was down to 2 things: 1 - Poor Seeing As the subs were downloading I could see the seeing fluctuation and they would vary from my alltime low of 1.89" to 2.5" over the course of 20-30mins. The majority were coming in around 2.4" on one night and 2.8" on the other. 6 - Poor Focus I cheaped out on autofocus for my 150p (using the Skywatcher DC Focus motor) and I think this was hurting my FWHM measurements. Autofocus works (I get nice V curves) but I dont believe it ends up in perfect focus very often (if at all). When I start imaging I therefore allow autofocus to run which gets me a set of HFR measurements (using SGPro) for the target/conditions and after it completes I manually tweak the focus until I beat/equal the best HFR during the autofocus routine. I use filter offsets and manually refocus if I see my HFR measurements drifting. This has significantly improved my FWHM measurements. The CN thread has definitely helped my images; it has made me obsess over focus and really chase the best values I can obtain...

I cheaped out and did the same. It is completely functional and I initially thought it completed autofocus in sgp perfectly with excellent v curves. However when I looked closer i realised it often misses the optimum point when it 'returns' to its calculated optimum. When focussing manually I averaged 4.5" fwhm and after implementing this as autofocus I also averaged 4.5" fwhm. However, during the routine it would dip into the 3" range so there was room for improvement. When I start for the evening I run autofocus to gauge my potential best, and I then manually adjust focus until I am acceptably close to that. It takes a few minutes and is somewhat fiddly but it is quite easy to do sitting in the warm! By following this routine my fwhm have been as low as 2.4"; a massive improvement. Using a filter offset of a few steps in sgp also appears to work well, presumably because the amount of movement is minuscule and its error is therefore tiny as well?

Do any of these units lend themselves to temporary usage, I want to monitor for cloud/rain when everything is outside but be able to pack it up when finished (usually the following morning but potentially a few days later if the weather is more settled)? Dont want to buy the USB version because my long term plan is an automated dome. Ideally I want to get a weather sensor I can use now and then transfer it to the dome once it is built...

You have definitely inspired me to try and improve my b mask focussing, HFR focussing in SGPro is time consuming (but I have found it very accurate). Did you manage to inspect the filter, although I am guessing the difference between 2.1" and 2.75" is large in measurement terms but miniscule in actual terms?

I need to work on my b mask focusing in that case! Sounds like you need to check the ha filter in that case, have you ever tried measuring fwhm in different parts of the frame, such as with the pixinsight fwhmeccentricity script? If it was something on the filter you would expect differences across the frame?