Thank you very much Samir!!!!
OK, now we are off to a good analysis. 25 sec (=0.42 minutes) to mid BoC Histogram at f4 and ISO 800. That means that your skyfog is at Visual Limiting Magnitude 3.5 (you can just about make out the head of Orion and you cannot make out the Milky Way at all). That is the same as roughly Mag 17.5 /sq arc-sec, suburb of a large city. A dark site is at Mag 21.5/sq arc-sec. Your site has a sky that has 4 Stellar Magnitudes brighter sky fog. Each Stellar Mag = 2.512x so your sky is 2.512^4 or 40x brighter than at a dark site. I.e. 40 Hours Integration Time at your site will give similar SNR (Signal to Noise Ratio) as one hour at a dark site. Note that typically you need 3+ hours at a dark site IT to get a very nice DSO image, so you have a major battle ahead! 120 hours IT ! The good news is that you can use reasonably short sub exposures, even at f5.9 and your skyfog will still be well detached from the origin. I suggest that you set ISO to 200 and use the longest subs you can track unguided. With so much skyfog it's hardly worth the bother of autoguiding. 2-minute subs at ISO 200 should show some detachment from the origin. If 2-minutes is too long to track well, just use one minute at ISO 400. As long as you can see a gap between the origin and the skyfog peak your subs will stack satisfactorily and you can skip autoguiding. The main headache is to shoot an awful of of subs! Each night you can get a max of around 3 hours IT before the target gets low near the horizon, but 180x1 min or 90x2 min is a good start.
What can you do to improve your situation? Get the camera modded and then you can use Ha narrowband filters. Frankly, your skyfog is too much even for the usual broadband light pollution filters like the CLS. Read this. Go for 7 or 8nm Ha and the narrowest OIII filters (12nm?) that are still reasonably priced. People are often scared to mod their cameras. No need. Get somebody commercial to mod it for you (with a rectangular bandpass UV-IR Blocker) and your camera will still work very well for daytime pics of Grandma. You just use Custom White Balance instead of Auto WB. If you go full-spectrum you will have the headache of sourcing a clip-in UV-IR Blocker for your camera model. Sort this out first, before choosing full-spectrum or you may later find out that you cannot use all your camera lenses with that camera. There are plenty of clip-in filters for APS-C cameras but more limited availability for full 35mm format.
Very interesting and useful.
Translation - I picked the worst possible place on earth for this hobby -
Yes, I am in the suburbs of a large city. Location is here ---
Seriously, I am still having fun, and learning, so that when I do move somewhere dark, I will know what I'm doing. If I start to get more serious, I think I can see the value in spending enough money to get into a dedicated camera and narrow band.
I hoping to try some AP with clear skies the next couple of nights, and with the ZS61 I can do a couple of minutes unguided so I will try some things you suggested if the clear sky forecast isn't wrong. I've had zero chance to try anything this Winter due to cold, snow, wind, clouds, other things going on, etc. so just getting out and trying on something will be fun.
Samir's advice is good, but do not despair. I have a good deal of experience imaging in light pollution. Look at my astrobin, mostly done in skies only a bit better than yours. Red Zone, Bortle 7, mag per arc sec squared low 18s.
There's some narrowband, especially more recently, but some broadband also, it's not impossible. I'm not a big fan of broadband light pollution filters, some use them, some don't.
Good gradient reduction in processing is essential is those skies. There are good tools in PixInsight, Star Tools, Astro Pixel Processor. The Gradient xTerminator addon for Photoshop. More total imaging time is also essential. My rule of thumb is that one hour is minimal, two better, four is good. Serious folks do ten or more, imaging over multiple nights.
A couple of things, less important. LRGB works better than One Shot Color in light pollution. It gathers data faster, and more data is key. The filters have a notch where sodium vapor lights emit, that's useful.
One darn good idea is to go halfway. Get just an H alpha filter (O(III) is substantially more difficult). Either mod the camera or get one of the new CMOS (mono). Shoot H alpha in black and white, which can be really nice. You'll see some of that on my astrobin. I do have a good mount (CEM60), I do 10-15 minute exposures. You either need a low read noise CMOS camera or, a good mount to do longish exposures.
Edited by bobzeq25, 02 March 2018 - 11:25 AM.