theropod

Hey, Car starting batteries are not designed for deep cycling, and will have a very short life in that application. Starting batteries are designed to provide short bursts of high amperage, and to have the power removed to start the engine rapidly replaced. Your mount has internal voltage regulation and should accept direct current voltage up to a specified point, and down to a certain point. Your owners manual should detail these specs. Stepping motors will work with a supply voltage that can vary quite a bit, but whether the driver will accept these voltage swings is another matter. Again, the user instructions should make this clear. I would look for a battery pack designed for the task, reference the user manual and be sure to install an in-line fuse rated about 20% over the expected running load to protect your mount from those “Oh no!” moments. A battery SHOULD provide the smoothest direct current possible for your mount. Just be sure what the mount will accept.

That eyepiece solar filter should be illegal, and no I’m not kidding. They might make good small arms targets.

Is the “sun funnel” design unsafe? How so? I’m talking about something without an eyepiece, just two simple lenses, that projects an image on to a screen/film/substrate, but much larger than done in the following link. Unless someone/something tore at the “funnel” I cannot see how it could be dangerous, and doing so would surely knock a scope off target. https://www.nightwise.org/sun-funnel I’m thinking of something 18” to 24” for screen size inside a soft hood. A big front shield, a hood one would have to use to see the screen and lack of direct viewing access makes the idea seem pretty safe. What am I missing? I wouldn’t leave any scope unattended around kids too small to be careful, and even older kids only if they haven’t demonstrated responsibility. I’m only exposed to my grandkids, and their cohorts, and my expectations from them have been met with flying colors. YMMV. I just think this is a simple solution that can be done safely and cheaply.

Wouldn’t a cheap department store magnifying glass and a low power metal cased loupe work fairly well? I bet 1/4” foam core poster board, in black, could be flex glued using silicone (hot glue might melt) together to make a passing projector. A project I’ve thought about a good deal. Simple square boxing with a detachable huge front shield. Finding some nice projection material (finely frosted/etched glass plate, or maybe a film adhered to clear plexi) has been my hurtle. Yes, I’ve seen the sun cone design, but I want a larger image! Color aberrations aren’t as noticeable, to me, using projection as in normal viewing, like looking at the moon. It might be fun to see what us CN’ers could come up with that is cheap, safe and simple. Very briefly I have used my 32mm Plossl EP behind an old 4” scratched up simple magnifying glass to project the rising sun onto the side of my house. The sun was 4’ across! I was in the Willamette valley of western Oregon during the 2017 eclipse, and I used half of an old pair of very cheap tiny binoculars to project the sun onto some thin paper. Sun spots and rough edge of the moon shadow were clear and crisp, and my iOptron SkyTracker Pro kept the sun on target. Travel restriction forced me leave my tripod at home so I had to zip tie one of those octopus micro tripods to a steel T post on the edge of a field, blind align by phone coords and use the settings on the little mount. Anyway, I gently touched the bino half from time to time, and it was never hot hours either side of totality.

Yep. Us meteor hunters (and other widefield folk) east of the Rockies (and nearly all tropical regions) have had many exposures “polluted” by these bugs. Late spring seems to be the worst, but just one blinking firefly sure can ruin a long exposure. I’ve noticed that bats absolutely refuse to take fireflies, and will actually turn away from them, so they are no help. I’ve had to sit with my remote shutter release in hand and start new exposures over and over because a lightening bug strafed my position. I’ve ended a few sessions early because the darned things were massed in squadrons.

The Easy Driver can drive a unipolar motor (5 wire) in most cases. Isolate two pairs of the 5 as independent coils (phases) by testing for resistance. Infinite resistance means not a pair, and a few ohms means a pair. The usual common wire is not used. Attach these as pairs to the output locations on the Easy Driver. Full control by a Nano of either a unipolar or bipolar stepper is possible using that Easy Driver (within current requirement limitations).

Not knowing if this is the correct sub forum or not I accept admin/mod discretion in replacement to a more appropriate location. It seems spherical aberration has been solved. Does this mean we can get large single glass refractors? https://petapixel.com/2019/07/05/goodbye-aberration-physicist-solves-2000-year-old-optical-problem/

I think you should look into using “unsigned long millis” to control/eliminate your sktech halting delay statements. I am currently rewriting my code for the DIY alt/az I built employing not only this feature but also employing proportional motor speed based on joystick mapping. Since I am not a C expert by any means this is a steep learning curve for me, but the Arduino is capable of great precision if the code is written tightly. Even you simply change your current delay statements to delayMicroseconds you can achieve far greater timing control. Yeah, the same desire to mess with things is part of my makeup too.

I'd love to see a cell phone imaging contest. R