M51-again! - New experiment in manual guiding (& pain...)

[Alestrom]

M51 again, but a different experiment in manual guiding.

This is the genesis of an idea that has been knocking around in my head for a while now - I cannot mount a proper guidscope on my Skywatcher 150 and EQ3-2 as the weight would be too much. So I have bodged a guidescope out of a National Geographic 50mm toy refractor, the lens from a barlow and some other bits. I mounted this on the empty declination motor lug using a ball-and-socket joint, gave it a go last Sunday. Balances with some to spare, I may post the details of the modification on the DIY Astronomer section if anyone's interested? I also may review the scope as it's kind of cool in a really naff way

I was able to guide sitting on the ground in a kind of lotus position, R.A. control in one hand and the shutter release in the other. I timed the exposures with the stopwatch on my phone.

The prof of the pudding is of course in the eating - this is the result of 6 x 4 minute exposures (ISO800) and 7 darks frames. I would have gone for more, but the clouds had other ideas (my back would probably have allowed me ten frames which was my target). This is my fourth attempt at processing the stack (in PixInsight LE), still not right it but the best so far.

I have also attached a test frame which was unguided as a comparison. The guiding is certainly not perfect, but definately an improvement... The question is, now do I attempt to modify the hand controller to accept an webcam guider input, or just wait til I can afford a 'proper' setup

I hope you like and find this of interest - clear skies.

[samtheeagle]

Alestrom, myself, and a few others here on the forum are using 50mm finder scopes for guiding, and they work a bloomin' treat I also looked at the Nat Geo scope you mentioned, but as I already have a 50mm finder...

And as far as the hand controller mod goes it's very easy. If you can drill a hole, and perform the most basic of soldering operations you'll have no trouble with it. There's only one note of caution I'd mention, and that's inside the hand controller there's a ribbon cable that connects the two circuit boards. I found that this was VERY delicate, and one of the connections broke It wasn't easy to fix... If you've got a hot glue gun I'd highly recommend dumping some of that in there to protect things.

And great pic btw! I can't imagine trying to do it all manually!

[Alestrom]

Cheers Sam

I saw you post with the write-up of the hand controller mod, looks well worth a go. One thing springs to mid which is that I only have the single axis rather than the double one, would the process be more or less the same?

I considered using a finder, but for manual the focal length isn't long enough and the NG scope has a focuser which works surprisingly well.

[samtheeagle]

Yes it should be very similar, but it's hard to say without knowning the layout of the circuit board. But essentially it should be a case of soldering 3 wires to the appropriate places.

I think I'm correct in saying that if you only have the RA drive then you need to get your polar alignment as spot on as possible, as the DEC wont be getting corrected for any errors.

[Alestrom]

That is right, some of the drift in the picture is actually from that rather than R.A. I think, I drift aligned to allow for 2 minute exposures but then I got carried away...

Cheers for the advice