Gina

I have a weather station project but not really done anything to it for some time. I had an Arduino based logger working a few years ago before the RPi came out. Not sure whether to use that or start again with the RPi. My main problem is having too many projects!!

This is indeed a problem and I'm looking again at my structure. Torrential rain can be blown upwards by storm force winds and I am on an exposed hillside. Previous versions worked because they only used sealed reed switches with a multicore cable down the mast and into the observatory. Unfortunately, the anemometer disintegrated - it was a commercial one, and I decided to make my own. I'm considering a new design combined with my ASC but not sure about the windage affecting the ASC. May be better on a separate mast.

Thanks Wim. Yes, I know it all depends on total integration time. What I really want to know is whether there's any benefit from using 2m exposures rather than 4m in view of the greater disk space required.

I'm sure this has already been discussed but please bear with me. I know that in general a CMOS sensor wants many short subs whereas CCD wants fewer but longer subs. The question is how far to go with this. Also, CMOS sensors have a gain setting. What I want to know is whether I would capture as much very faint nebulosity with say 100 2m subs as 50 4m subs, other things being equal? Also, what gain setting for the ASI1600MM-Cool for imaging DSOs, particularly nebulae.

Would I get as much very faint nebulosity with say 100 2m subs as 50 4m subs, other things being equal? I know that a lot of my experience with CCD sensors doesn't apply to CMOS.

I presume you mean an external aperture ring as stopping down with the iris causes diffraction spikes. The 200mm lenses are probably about the same quality being the same make and similar vintage.

I was considering a 200mm lens for more resolution but these are f4 - almost 2 stops slower. That would mean at least 6-8 hours total imaging time.

Went back and checked - gain was 360 which I think is too high. Not sure about 240s exposure but I don't want to lose the faint stuff. Maybe reduce gain to the next "step" down of 240 (I know you can set any value up to 600) but keep to the same exposure. Advice from ASI1600 (or other CMOS) experts always very welcome.

Thank you Wim. The lens is a vintage SLR film camera lens. Asahi Super Takumar as used with the Pentax cameras. 42mm x 1mm thread. There was a smear on the front of the lens which I have removed - the insides look clean. Alnitak would probably be improved by shorter exposures and/or lower gain. I'm still experimenting to get the best settings for this camera.

Very pleased with mine.

Watching it. Seen it before but worth watching again. Missed 20m of it as I was out.

Nothing like that in the FOV.

Just been out and checked the lens iris and it's wide open - nothing I can see that would cause a diffraction pattern.

I don't think that circuit is suitable for the sort of batteries you would use for astronomy. You'd probably want to charge around 5A as with a car battery charger. Some years ago I designed and built a 5/10A battery charger for our tractor battery. I guess solar panels may only be capable of trickle charging though unless big. Have to say I'm not very familiar with solar panels.

Where multi-strand wires are too big for crimp connectors, I too have removed some strands to slim them down but not used solder as that defeats one advantage of crimp connectors - that of not being affect by heating with high currents.

Next dry day I'll pop out and check the lens.

Than you Dave. The lens wasn't supposed to be stopped down but I noticed the diffraction pattern and wondered I I managed to turn the iris ring by mistake. Yes, nice to be back. Makes a change to have something I think worth posting!

I do the same.

Amazing - great image. Not see this before either.

Captured on Friday night last week (3rd January) with 3nm Ha filter, 135mm f2.5 lens and ASI 1600MM-Cool camera on EQ8 mount without guiding. 55 subs of 4m each giving a total of 3h 40m. Captured with RPi 3 running INDI firmware and saved in Linux Mint desktop indoors running KStars/Ekos. Simple processing in PixInsight for star alignment, stacking and curves, followed by cropping and scaling for posting here. No calibration frames were used. Here are three different fields of view, obtained by cropping the image. First is about a third of the captured frame and third is full resolution (4656x3520 pixels cropped to about 1200).

I wasn't totally clear what we were supposed to do either but thought make a pattern of your own.

What are you calling that, Helen? I've been trying hard to see some sort of pattern. Wonder what others see in it.

I've used Mini-DIN connectors in the past but found them dreadful. Standard DIN connectors are also dreadful. Rarely see them these days so I guess that proves my point! Cheap and nasty is not the way to go for astro! Don't "spoil the ship for a hap'orth of tar"!! I use GX12 "aviation" connectors and find them very good. Better than XLR though they aren't bad.

They didn't say but it looked like plastic.

I make my own as you probably know.