wimvb

I’ve read somewhere that the standard 120MM works better if you update the firmware. But I’m not at all sure that this is needed with the newer models. Initially, the 120MM used too large data packets, and didn’t follow the usb standard. Updating the firmware fixed this.

Typo 120 of course

If you go for the non-mini version, make sure you buy the ASI220MM-S ASI120MM-S, which has usb3, and not the (older) ASI120MM. The latter has/had usb compatibility issues. The mini version is ok, though.

Taken with my iPhone, no processing.

Before I built a ror observatory, I used a tool shed as a roll away obsy. Have a look at the first post in this thread. You could do something similar, and use the shed to house you and your computer, while imaging. It would be easy to install a fold down table in such a shed. Just a thought.

Here's my attempt with PixInsight. In a wide field such as this, with a lot of stars and weak nebulosity, it's difficult to remove gradients. A few tips: use flats to remove dust bunnies take more (and longer?) exposures in order to reduce the noise. In this image, it's dificult to see what's noise and what's stars. if you want to concentrate on this type of imaging, you should look into astro-modding your camera, so that it will pick up more Ha signal.

Yes. LP, especially in wide field images, shows a gradient as well as a general increase in brightness.

After reading old threads about this scope, I got the impression that it's easy to mess upp collimation if you replace the focuser. The critical distance in this scope is between the corrector plate and the secondary mirror. If you can't mount the replacement focuser in exactly the same position as the original, you may be in trouble. This may be of interest: http://www.iceinspace.com.au/forum/showthread.php?t=140193 (Mind you, that discussion is 5 years old)

Go for it while you can. Yesterday @gorann notified me of this: http://www.iceinspace.com.au/forum/showthread.php?t=183924 It's a great scope. Skywatcher have upgraded parts of it over time. The low profile focuser works well with my asi camera + filter wheel and oag. But I had to correct the wobble in the built in extension tube to get it where it is now. A strip of aluminium tape on the tube fixed it in place.

Well, here's a glitch. I planned to leave the JST connectors in the anemometer, and order some sockets for my new circuit (with AVR). But it appears that the connectors have a pitch of 1.3 mm, while the only ones I can get here either have 1.0, 1.5 or 2.0 mm pitch. I want to avoid cutting the leads in the anomemeter. So far, i haven't made any modifications yet. Otoh, i tested the anemometer with a home brewn python program with RS485 communication, on my Windows laptop: # -*- coding: utf-8 -*- """ Created on Tue Jul 7 00:00:52 2020 @author: Wim """ import serial, time import serial.rs485 mySer = serial.rs485.RS485('COM9', 9600) mySer.rs485_mode=serial.rs485.RS485Settings(True, False) cntr = 0 while cntr<10: mySer.write(b'\x01\x03\x00\x16\x00\x01\x65\xce') mySer.flush() data = mySer.read(size=7) myNumber = (int(data[3])*256 + int(data[4]))/10 cntr += 1 print(cntr, 'wind speed:', myNumber, 'm/s') time.sleep(3) mySer.close() This works like a charm in the Anaconda/Spyder IDE. There is a response delay in the measurements, but it's within specs. Tomorrow (or rather, later today), I will try to program this on an old Raspberry Pi. (And yes, I know that using 'time.sleep()' is bad programming. But this is just a Q&D test.)

You're not the first. 😉

I'll measure my anemometer, and do the calculations. Then remove the mcu that's in there now, and replace it with an attiny/avr. I'll (try to) program this as an i2c device. As I wrote earlier, my wind meter has 8 magnets, and will give a higher frequency per m/s wind speed. It's still too bad that I can't keep the original calibration. But I can always hook up the current mcu in an experimental setup, and test it. Then put it back in if I can get it to work. I just need to order a few jst connectors, so I don't have to cut any cables.

Just unscrew the az pin from your tripod, and do a dry run. The single larger hole at the top should be the one.

Just different units for Rrc. mm in one, and m in the other.

That should depend on the diameter of the anemometer head (more than the cups). I’ll read that article you referred to. Thanks.

Did you do any calibration to get wind speed in m/s, or does your anemometer just report revolutions/minute?

I opened my anemometer just the other day. It contains 1 reed switch in the static, bottom part, and 8 (!) neodyme magnets in the rotating top. Three wires lead to/from the reed switch: Red, Black, Yellow. The whole sensor part is covered with silicone, so i can't see how it's connected. My guess is that the red wire (which supplies 3.3 V to the sensor) is connected to a resistor which is in series with the switch. From the resistor/switch, the yellow wire gets the signal out. And the other side of the switch is connected to ground (black). I verified that the voltage on the yellow wire goes low whenever a magnet passes the reed switch. The pulses are fed into a microcontroller for processing, and then into a MAX485 type chip for RS-485 signal conversion. The MCU is this one (overkill if you ask me) https://www.st.com/en/microcontrollers-microprocessors/stm32f030f4.html I still haven't got the anemometer to work with either an Arduino or an ESP32. But it does work with a Windows based Modbus test tool. And my Arduino/ESP32 software works with a windows based modbus slave emulator. I'm leaning more and more towards butchering the anemometer and just get the pulse output of the reed switch. If I remove the mcu, I will also lose the calibration. Hacking the anemometer isn't much of an issue, but I would need another wind speed meter to calibrate the hacked device. Otoh, I could then turn the anemometer into an I2C device, as are all the other sensors in my weather station.

PixInsight for dso. It’s available for ms windows, mac os and linux. It has all you need built in, and is imo, not more dificult than any other software.

Just remember that astronomy started as astrology. The great Tycho Brahe was employed by the Danish king as an astrologer. As such he could study the night sky and create accurate catalogues of the planets’ position, which Kepler later used to formulate his ”laws”. As for the original question, I use astrobin, sgl and the Swedish astronomy forum to publish my images, but am considering flickr as well. There are also several astronomy groups on FB.

Thanks for that great write up, and very nice results. With your dslr, you don’t need a computer outdoors. Just make sure you have enough fresh batteries when it gets cold, or invest in a mains adapter for your camera. You can also add an intervalometer, to allow more exposures in a series.

For nb or lrgb imaging, you can correct for this by adjusting the exposure time. You can’t do this with osc, where it will cause a colour cast. Unless you use a colour light source, that colour cast is about all that will happen.

I can relate to that. Before I moved to my current location, I lived in the suburbs. Across from my observing location, some 20 m away, there was a street light to the South East. Unlike in some other countries, Swedish street lights are not turned off at midnight, but are on all night long. And right across the street, to the South, neighbours could leave their bathroom lights on all night.

We are compensated during winter with 12 hours of darkness. Very nice image. Is that a single exposure of 1200 s?

I just took a picture that shows the sky, looking West, at abt 23.30 (11.30 pm) local time. South is to the left, North to the right. It's bright enough to read, if it wasn't for all those ... mosquitoes. The foreground looks brighter irl, but the sky matches about what I see. And this is how sky darkness is for me throughout the year. As I 've said before, no astronomy up here during the months that don't have an "r" in their name.

Yesterday I was enjoying the beautiful night after a very hot day. Just before midnight (daylight saving time), the only star I could see was Vega. Just past 1 am, the supposedly darkest time of night, I could only see the summer triangle, Vega, Altair, and Deneb. With binoculars (see my signature for details), I could see a few more stars in that area of the sky. To the north, I had the skyglow from the sun, just below the horizon. I live away from the light dome of Stockholm, and my winter sky darkness is about 20.7 mag/arcsecs2. I'm curious, just how dark is the sky where you live, this time of year?