rotatux

Maybe try a 2D "fluid" head (the kind used by video makers) ? Mine handles up to 4-5kg, but there are some more robust ones which can handle 10kg and even more, and you usually don't pay the "astro tax" on them, so you may get a very good one for the price of your SW/Bresser/iOptron/Omegon wedge. I'm using mine with a Minitrack LX3 plus camera and lens (~3kg total) and it's a breeze to setup and lock the altitude, with no shift while locking, and no play once locked. YMMV. PS : of course you would need a good tripod and photo plate to fit, if you don't have them already.

I'm not a user of DSS, but it definitely has outlier rejection available. From some screenshot I found it seems "Average" is the default, so as a start try one of the two options outlined below :

Hello... what is this showing exactly ? If I assume this is the result of stacking, then these tracks may be from hot pixels moving with sub-frame registration. Then yes dark frames and/or bias should help, but not only... I also suspect something else : as these hot pixels move with the result of registration, they should be eliminated by the stacking algorithm rather then leaving a trace. That is, if you used the correct stacking algorithm => You should activate and use some form of outlier rejection, which is often an option in stacking programs, they are called differently so I will just cite "sigma clipping" or "winsorized sigma clipping" but there are others. If you tell which program you use, maybe others using the same will be able to complement this answer.

Certainly. As said it has already been done. AFAIK this kind of deformation gives a "chainette" curve, which is a hyperbolic-cosine, which in turn is near hyperbolic and parabolic. Other deformation based telescope mirrors about which I read/views in the past 40 years : using vacuum behind a spheric mirror to turn it to nearly parabolic using mechanical traction with a screw behind a spheric mirror to turn it to nearly parabolic (I think it was in old S&T)

Yes it looks like some HTML somewhere has eaten end-of-lines. The source HTML shows the same, so no way to recover it, apart by breaking the lines yourself. Don't know what was used - TL;DR. If you want to use the stepper with ULN2003 you have no choice but to use as unipolar (4 energy + 1 ground = 5 wires). Of course you could cut the wires, let the ground alone, and connect the coil ones to a bipolar controller, but I don't see the point (destructive mod, same stepping, double coil inductance to fight).

Having tried a 44M-6 myself I could have predicted this result and can tell you have to close at least 5.6 to improve a bit (far from perfect) on this lens. Its renowned swirling bokeh is due to severe astigmatism so not much can be done. However don't ditch all old glass, as most are much better than that. e.g. a 50mm/1.7-1.8 from Asahi/Takumar, Pentacon or Minolta will be perfect or nearly from F4 on.

Gives me another idea. ESP32 has touch sensors. You could also use capacitive pads to check alignment : I mean, 2 facing conductive pads, one on each side of the rotating parts, and the touch would trigger when the pads are aligned enough (only one side needs to be connected to a pin).

+1 Vlaiv is mainly right and here is why : on embedded devices the duration-based sleep is approximate, in nominal situation it's usually a minimum but in case of hardware interrupts some devices can exit the sleep prematurely and return control to your program. So usually this kind of loop will drift from its target period, so much that it will be useless for sky tracking. Rather than turning to power consuming "active" loops, you can get the best of both worlds by using time monitoring in the loop, which is called a fixed-rate passive loop (vs your fixed-delay passive loop). The code to use is basically the one shown by Vlaiv, completed with : as calculate_time_of_next_event function : time_of_next_event = time_of_next_event + target_rate_average_period (can even be a float) use as microsleep : sleep(time_of_next_event - current_time()) This kind of loop will automatically compensate for both early and late sleep exits on the scale of several steps, to achieve a very precise average rate (depending on the precision of your embedded device's clock). EDIT : crossed with other answers but nothing contradictory

Hello, nice project. Just like a motorized barn door tracker, you need to count steps of each part of your mechanism, and join them (multiply / divide depending on input/output situation) to write an analytic equation. Parts include gears (number of teeth per full revolution) of mount and intermediate transmission, stepper motor (steps per revolution), and sky (360° / ~23h56mn). The base equation is mainly : 1 main mount gear revolution = 1 day. Develop the left part with gear ratios, down to stepper total steps and period, then you will be able to extract the period = seconds or milliseconds in 1 day / some number of steps. HTH

I can see double spikes on some, but none clearly offset from centre ; I read this can be caused by twisted spider vanes.

Very nice already (esp. star colors around Crab Neb.), shows if needed that AP is possible with Alt-Az. I hope you will add more subs to those, they deserve to gain more depth and detail.

I already understand the enough repeated principle of the primary baffle, But that's not what I want, because I believe (can't re-check at the moment) to have a quality-chamfered mirror variant described by alacant. My problem is now *only* the shadows from the clips -- as I already fixed the protruding focuser ; I find the remaining (uniform) diffraction from the bevel acceptable or even nice I'm also not very comfortable with the silicon solution to remove the clips, as I typically transport the OTA upside down in a photo suitcase.

Yes my first reaction seeing your shot was about pinched mirror. The clips, if you keep them, must *not* be tight but just screwed enough to secure the mirror and avoid any play and vibrations. Of course other answers (astigmastism, CC spacing) are also valid. BTW about an aperture mask, to avoid reducing the aperture I'm thinking about masking just the clips with half-circles of cardboard or hard paper, which would be sandwiched in the head of the clips. Would it have a chance to work ?

That's because USB cable length is limited depending on standard : AFAIK 3-5m for USB2 and 2-3m for USB3, as there's a drop in voltage with length the SnR for high frequencies is too low and doesn't allow high bandwidth of USB3. Hence the behaviour you observed. But that's only the case with dumb cables such as the one you point. With active cables you can reach longer length as the signal is repeated and stronger (at the price of power usage, and a bit of latency and bandwidth). So if you really want to try 5m with USB3 you need to buy an active cable.

Hi, I'm in a setup process for a recently bought Altair 224C on a Linux netbook. Having driver problems with the cam, so I'm not yet operational enough to be sure. Indigo seams richer (more drivers) and more polished than Indi, with a similar or mostly compatible protocol. AIN Imager looked very nice when I tried it, probably better than CCD Ciel which seems the nearest alternative. Same problem as you for training in-house without a starry sky. Asking myself if a sky print in front of a lens would trick it 😄