Stub Mandrel

Ditto, I don't expect a hard-and-fast rule, but presumably anything that, as a minimum, encompasses an extended group of DSOs or a constellation (rather than a compact group of DSOs like the deer leap or the area around M42)

... behind the space heater

Just goes to prove that using a PIC needn't spoil your whole day

I found this (I usually use AVR Assembler) http://www.hobbytronics.co.uk/arduino-timer-interrupts Just change the code to give the correct interval for your stepper and pulse the stepper instead of an LED: /* Example Timer1 Interrupt Flash LED every second */ #define ledPin 13 int timer1_counter; void setup() { pinMode(ledPin, OUTPUT); // initialize timer1 noInterrupts(); // disable all interrupts TCCR1A = 0; TCCR1B = 0; // Set timer1_counter to the correct value for our interrupt interval //timer1_counter = 64911; // preload timer 65536-16MHz/256/100Hz //timer1_counter = 64286; // preload timer 65536-16MHz/256/50Hz timer1_counter = 34286; // preload timer 65536-16MHz/256/2Hz TCNT1 = timer1_counter; // preload timer TCCR1B |= (1 << CS12); // 256 prescaler TIMSK1 |= (1 << TOIE1); // enable timer overflow interrupt interrupts(); // enable all interrupts } ISR(TIMER1_OVF_vect) // interrupt service routine { TCNT1 = timer1_counter; // preload timer digitalWrite(ledPin, digitalRead(ledPin) ^ 1); } void loop() { // your program here... }

If you need accurate timing (which you do) you need to use a timer interrupt. just use it to reset the timer and set a flag. Outside the interrupt another loop can watch teh flag and when it sees it set, step teh stepper and reset the flag.

That bad eh? It's just OSC RGB :-(

I use my moon and skyglow, which is quite a cheap one but works well. Good point though, it may have killed all the yellow in the flame. If it'[s clear tomorrow I will have another shot. Tonight was a bit of a write off for reasons far to complex to explain :-( My previous M1 just looked like cotton wool, this one has some 'cobweb' texture so quite pleased. I will have a go with the 150PL which will double the image scale.

To be honest I gave up trying to get the flame to be a different colour from the other nebulosity :-( In contrast, I just went to my M1 data and that almost processed itself:

Far from happy with the colour in this one. An hour and ten minutes of 2 minute subs is far from enough here. The cooled subs show more detail than last years efforts, but colour is p*** poor and sadly mixing them wasn't very successful. I shall come back to this data and try other permutations - and add more cooled data, skies willing!

Possibly, I use a cheap (£10) moon+skyglow filter and it helps a lot. I still had a big yellow tint on the top edge, which I think was caused by my workshop lights

Go for the longer exposures Galen, 5-minute exposures turned out OK for me on the Pleiades last night:

See if you can get one of the new reticle polarscopes.

That's with guiding... Pleiades, 13 five-minute subs:

Here's my Andromeda galaxy from last night. 20 5-minute subs. Long exposures seem to give much better star colours.

Looks like an 'F' to me A show us your guitar thread might make some people's scope collections look restrained. Where do they all come from?

Nice to see it in the context of the two stars at the bottom of lyra.

Nice and crisp Stu.

Do you use a field flattener with it?

Mirach and Mirach's Ghost using the 150PL and the ASI 120MC.

Last night was amazing after the moon went down. I could see traces of the blue nebulosity through my 50mm finderscope! Orion was coming into view around the house at about 12:30, but my tracking battery was down to 11.4V after six hours running so I packed up :-(

This picture won't win any prizes, but i will haul it out when people say you can't track DSOs with an EQ3. M15, 21.9 second unguided subs at an effective focal length of 3600mm. 150PL + x3 barlow. ASI120MC, which seems to have produced mono PNGs. Not sure how... I admit I did dump about a third of the subs.

Importing my subs! I know I have reasonable data for Uranus. I woke up screaming in the middle of the night when I realised I had misjudged the FOV of my finder and the star I was trying to hop to Neptune to from was Neptune :-( All I needed to do was drop the exposure...

Ha! Currently capturing 20-second subs of M15 with my ZWO ASI120MC with 3x barlow. That's 3,600mm focal length! This will be interesting!

That's how I started doing planets, but DSOs? that's dedication!

Be warned, M74 'has the lowest surface brightness of any messier objects'!