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Wide angle shot of Milky Way in Cygnus. 10 min total (4 subs of 2.5 min each) at ISO 100. Nikon D3200 with kit lens at 18mm (f/5.6). Tracking on a skywatcher 150p EQ3-2 mount - no guiding.
As a newbie in AP I recently discovered that astro imaging isn't as simple as I imagined, it's not just "pointing and shooting".
The main point is that I need a tracker that will follow the sky's movement. But after seeing the prices at which decent trackers are sold I decided to see if I could build one myself from spare parts at my workshop. Turns out that I can, using two planks of wood a hinge, an arduino, a stepper motor, etc. So I decided to get to it, I have built the connection between both planks of wood with the hinge, but have now discovered a problem. After some investigation, I realized it's quite commonly named the "Tangent Problem" (the rod forms a 90º angle with the bottom plank). So the solutions offered vary from curved rods to involute pieces of plastic and tilting the rod.
I also saw another solution that was adjusting the speed at which the rod moves, and since I'm going to be using an arduino-driven stepper motor, I decided that this was the way to go. The problem is that I don't know in what ratio the speed has to increase over time to compensate the "Tangent problem".
That's why I decided to pose my question here as I'm sure someone must have done it already.
Sorry for my bad english, it isn't my first langnuage.
Thanks in advance and clear skies,
TL;DR: are there any cheap ways, including secondhand, of mounting a 130P-DS for not-completely-terrible results?
I am looking to buy a telescope as a gift for a family member. I had in mind a budget of around £150-£200, and from looking at advice had almost settled on the Sky-Watcher Explorer 130P. But then I realised that there's a good chance that if they get into astronomy there's a good chance that my relative will want to do some photography, and would probably be interested in attaching their micro four thirds camera. I've learnt that the 130P is not great for this as you cannot get prime focus, so you need to look at the Sky-Watcher Explorer 130P-DS instead.
Great, I thought! It's a bit cheaper, but it isn't available in a kit with any form of mount. OK, I'll need to get one of those too...
Then I started looking at mounts. Oh my, those things crash through the top of my budget! Even the EQ2 mount on its own, when you can find it, is about £115.
(Given that you can get the spherical version of the Sky-Watcher 130 on that mount for £155 from FLO, that seems to value the OTA part at somewhere around the £40 mark.)
So, I'm after advice on whether there is an affordable way of doing this.
I've read enough on this forum and other sites around the web to know that the main recommendation is that the heavier duty the better. Something like an EQ3 or upwards. And that for AP a lot of people seem to view an HEQ5 as a starting point. But since I can't stretch to that, I'm OK with leaving it as an upgrade path for my relative if that's the way they want to go (or option for future gifts!).
I know that for next-to-no budget I'm not going to be able to give something that will get the best out of the telescope. I know that getting motors and whatnot to do the guiding that will make DSO photography possible is way out of the realms of possibility. What I'm hoping for is some sort of option that gives acceptable results. Usable rather than unusable. Limiting the results rather than destroying them! Getting this set up so that they can do reasonable observation at first, and maybe give a try at attaching their m4/3 camera to try photographing the moon. If that whets their appetite then mount upgrades can be possible later.
Since I'm planning on a new OTA, I'd be happy with going secondhand for the mount.
I've been trawling ebay, and see the odd thing like this come up:
To my untrained eye, it looks like there's an EQ2 mount on that, so I'm wondering whether that would do the trick. (Working on the, possibly faulty, assumption that if EQ2 is viewed by Sky-Watcher as being sturdy enough to supply as the kit mount for the 130 and 130P, it's probably up to scratch for observing with the 130P-DS too.)
Even that, at another £58 inc postage for the buy it now would be over my budget, but I'm wondering more generally whether trying to grab something like that to essentially discard the tube would even be feasible as an option if I can get one at the right price.
Or, of course, I'm open to any other ideas and suggestions that the forum might have.
Thanks in advance, and clear skies.