AP baby steps - M42

[Squagnut]

I just got a C9.25 SGT with AP in mind - I'll upgrade the mount eventually, but it'll have to do for now, while I accumulate other kit. But for a taster/experiment, I took a 15" exposure of M42, knowing that the mount wasn't perfectly aligned (indeed, it wasn't even level) so not expecting much - really I was trying to resolve the (usually overexposed) Trapezium rather than capture the nebula. No live view on a dSLR makes for tricky viewfinder focusing - I can say this with authority. Taken with a Nikon D3000 on a Celestron T-adapter. I'm encouraged.

Un-resized and cropped:

[1981suede]

You should post this in the deep space imaging section. Still, nice detail for a 15" effort. Not bad focus either. You should get a bahtinov mask though. Makes life so easy!

[NickK]

The mount AP alignment will (a) allow better separation of the trap stars and ( will give the objects a higher signal to noise ratio.

[ollypenrice]

You're on your way! Well done. It looks to me as if the scope is trying hard to reslove the 5th star but is being beaten by the tracking.

For imaging at these long FLs the mount is the key. It has to be good. It does not have to be level, something which causes a lot of confusion. It can be easier, though, to drift align successfully if it is level because there will be less interaction between altiude and azimuth adjustments. However, it would be better to spend 10 mins extra on drift aligning than ten minutes extra on getting the bubble level centred.

Bahtinov mask - yes, essential. Looking at stellar images will not allow you to find crtical focus other than by good luck, which I wouldn't bank on!

Probably an off axis guider would be best for your setup because of the FL and because the mount is already working very hard with the weight.

Olly

[Squagnut]

Thanks for feedback all!

Yes, I'm looking at an OAG to keep weight down, but I'll upgrade to an EQ6 as and when - but I'd also like to keep weight/bulk down for transport, as I don't have a permanent setup just yet, and lots of northward LP issues (read: a streetlamp) from my garden.

A Bahtinov mask is on the 'to make/buy' list, along with a host of other things. But thanks for positive feedback - I have lots to learn and lots of mistakes to make yet, but I'm getting on the right track.

[ollypenrice]

In the DIY sectoion there's a thread on the simpler 'Y' mask.

Olly