When do you need a guide camera and scope?

[Gumph242]

I understand that to get really long exposure shots you need this extra kit. How long an exposure can you realistically get without them?

This is with a sw ed80 on a heq5 mount.

Ta

G

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[Amra]

Well I manage 1 minute subs at 1000mm FL, without a perfect polar alignment (but close), the ED80 has less FL so you should be able to track a bit longer without trailing provided that your polar alignment is decent. Also it's a smaller scope than mine so it will be more stable and less of a wind sail.

Someone reported doing 3-5 minute subs on these forums some time back if I recall, without guiding, don't remember what gear though... But I've certainly never managed that long with my 200P.

I did do a 5 minute sub with my camera on the HEQ5, but this was at just 50mm with the nifty fifty, can probably do 10 minutes with a ultra wide lens. 

Either way, good luck!

[nmoushon]

It depends on if your using a reducer or not too. I've managed 2min subs with just a basic polar alignment. I've seen 5min on an HEQ5 or EQ6 forget which one. But they did an extensive polar alignment with drift aligning and everything. But that would be a pain to do every night if you have to take down and setup every night, which is what I have to do so thats why I just stuck with my 2min subs.

[ollypenrice]

It isn't just a matter of 'How long at what FL.' It's also a matter of how many subs you throw away. I'd suggest that around 1min to 2min depending on your luck of the draw with the mount would be a starting point.

Olly

[laser_jock99]

If the polar alignment is spot on that's a good start. Then it's down to how good your mount is. Skywatchers are known to vary considerably in tracking quality- some need nothing doing others have to be stripped down and re-built to get the best out of them. Most are somewhere in between. I suggest you check/overhaul your EQ5 as necessary:

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

Then practice nailing down your polar alignment procedure. In my view a 'tuned' EQ5/ED80 combo should be able to do 120s or even 180s easily.

I had an imaging session recently when my guiding camera was removed and I was getting usable subs @ 180s 800mm FL without guiding on an EQ6. Ultimately you should think about the guiding route as it opens a whole load of imaging possibilities.

M33 stack of 4 x 180s unguided.

[Amra]

Nice image!

[peroni]

I've had my HEQ5 and ED80 for a year now and once I'd managed to accurately polar align with a level mount I could achieve 3-5 mins unguided.

But as Olly mentioned above, the longer the exposure, the more chance there is of something causing the exposure to be binned (e.g. planes, satellites in the shot, wind movement, mechanical errors in tracking) 

At 3-5 mins I can easily bin 50% of the shots but I have had my scope tripod on grass recently which probably doesn't help.

[johnrt]

The figures quoted above of 3-5 minutes with great care are pretty accurate, but even with excellent polar aligning via drift align method and precise balancing you will lose as many subs as you keep.

Go out and buy a cheap guiding set-up, you'll be able to do 10-20 minutes without issue on an HEQ5 and you won't lose a single sub, which is a precious thing living in a climate like this.

[stelios_t]

<snip>Go out and buy a cheap guiding set-up, you'll be able to do 10-20 minutes without issue on an HEQ5 and you won't lose a single sub, which is a precious thing living in a climate like this.

Besides, the hobby is too simple without auto-guiding. Who doesn't need to spend some more money and have a few more cables trailing around?       

[dph1nm]

30sec max at dec=0 on my HEQ5 with 0.9" pixels (1200mm FL + Canon 1000D). Still throw away quite a few of those. That is with  about +/- 15" periodic error (over 10mins worm period), which works out about right.

NigelM