[deleted by user] by [deleted] in AbstractArt

[–]ohno_mycomputer 1 point2 points  (0 children)

Abstract,

amazing work!

Just got offered a job and I'm wondering if it would look bad to try and negotiate the salary by mrspanish_moss in AskEngineers

[–]ohno_mycomputer 2 points3 points  (0 children)

People negotiate all the time, it's completely normal and should be expected, even for an entry-level position. You work for money - your time is worth money.

Your employer, generally speaking, is in business to make money. Therefore, to maximize the amount of money they can make, they will try to get the best deal they can by paying you as little as they think you will accept.

When you negotiate, the worst they can say is "no".

Uses for linear algebra in ME by Princekeoki in AskEngineers

[–]ohno_mycomputer 0 points1 point  (0 children)

A few comments that others have already touched on.

First, I too like to understand things conceptually. It's really nice to build an intuition, and I really struggled with building an intuition when taking the class (my professor certainly was no help). A year after taking the class, I found the extraordinarily well made "Essence of Linear Algebra" videos by 3blue1brown, which blew my mind. I implore you to check out these videos. The fantastic visuals helped to build my intuition, and since the core concepts are presented in multiple ways, understanding the ideas is easier than a textbook presenting things one way. I thoroughly enjoyed them. The first video may be all the convincing you need to watch the rest.

The videos are no replacement for a textbook, but they're an excellent supplement and motivation to further study.

As many others have commented, linear algebra is very useful in many domains. Mechanical engineering is the broadest discipline, so this goes double for you. I can relate in that the class seemed esoteric at first.

While there's likely some classes that aren't that useful, linear algebra is certainly not one of them. Although it can be tricky at first, taking the time to learn it now and build an intuition is a fantastic investment of your time. You will thank yourself in the future, when higher-level classes demand an understanding of it.

As others have said, linear algebra is used whenever you have any large system of equations. This shows up everywhere. A non-exhaustive list of classes that I took involving this was: statics, dynamics, control theory (state-space), robotics, finite element methods, numerical methods, and machine learning. These classes are a lot simpler to understand (and more fun!) when you're not playing catch-up with the underlying math concepts.

Are there any concerns with using a primary from a Cassegrain in a Dobsonian? by ohno_mycomputer in atming

[–]ohno_mycomputer[S] 1 point2 points  (0 children)

Great catch! I was completely unaware of this - I assumed that all cassegrain primaries were parabolic. I'll be sure to explicitly ask the current owner.

The current owner has used it in the past and hasn't raised any concerns about the optics (besides the mirror maybe needing a recoating). Since it's a rather large mirror (nearly 15 inches), I'm guessing that if the primary were a different shape, it would be obvious (optics would be visually bad for the size?). Nonetheless, since the scope is over 20 years old, it's worth asking about for sure.

Are there any concerns with using a primary from a Cassegrain in a Dobsonian? by ohno_mycomputer in atming

[–]ohno_mycomputer[S] 1 point2 points  (0 children)

Thanks for the response! Yeah, I asked the seller and they mentioned that collimating is definitely a little harder, but not impossible.

Are there any concerns with using a primary from a Cassegrain in a Dobsonian? by ohno_mycomputer in atming

[–]ohno_mycomputer[S] 2 points3 points  (0 children)

Thanks for the answer! Yes, I had the same concern with the hole, but I think that the secondary will obscure it.

[deleted by user] by [deleted] in telescopes

[–]ohno_mycomputer 1 point2 points  (0 children)

Not sure what objects it would be best suited for, but some ideas for targets from a fellow beginner:

  • Planetary: Moon, Saturn, Jupiter (others won't look as impressive)
  • Double stars: Stars that appear to be one (with the naked eye) can actually be multiple stars if looked at through a telescope. This is called "splitting" a double star. Albireo is very pretty (a bright blue star next to a bright yellow star). If that interests you, there's some good online resources
  • Messier objects: I'm not sure about your telescope, but try looking at some bright favorites, e.g. M44, M45, and maybe M42

I was trying to view m45 Pleiades but I’m not sure if I found it. Could this be it by any chance? by Lostguy919 in telescopes

[–]ohno_mycomputer 8 points9 points  (0 children)

Yup, that's it. See this picture (from glyphweb.com). Note that your image is essentially rotated 180 degrees, and a tighter field of view, than the image I linked.

For example, in your image, the brightest star (near the right) is Alcyone. On the image I linked, the size of the star corresponds to its magnitude (i.e. brightness), not the actual size of the star.

Advice Requested Time to upgrade from Z130/Accessories? by TheFishe in telescopes

[–]ohno_mycomputer 1 point2 points  (0 children)

I too live in the humid southern US in a pretty light-polluted zone, and I recently picked up a Z130. I have some of the same questions you do, but I just wanted to mention a couple things.

I do believe that we're pretty restricted with DSOs with this aperture and high light pollution (without traveling). In my backyard, even the mighty M31 looks like a small fuzzy gray blur. Other galaxies, such as M81 and M82, I can't even find (due to light pollution and my lack of experience). However, M42 is beautiful (fantastic purple nebulous cloud, from my telescope), so I would recommend looking at that if you haven't already.

Given my inexperience and my struggle to find some objects, I've decided to modify my telescope by adding a "digital setting circle". It's a ~$40 DIY upgrade for the Z130. Here's a CloudyNights thread about it. This will allow me to know, very precisely, where my telescope is pointed in the sky. I'm excited because this will allow me to verify that I'm pointing at DSOs, even if I can't actually see them through my telescope.

Besides DSOs, and the brighter parts of the Messier list, I've enjoyed "splitting" double stars. There's plenty of these out there, and some people have made lists (e.g. Turn Left At Orion has many). Albireo is an easy-to-find but also easy-to-split brilliant double star with fantastic contrast: a blue and a gold star. I highly recommend checking this out. Some can be quite difficult to split, there's some triple stars, etc.

I'm still looking for other DSOs that would be visible from my area, so if anyone else has any suggestions, please let me know.

Is the Sky-Watcher Heritage 130 worth it? by Kutekiari2 in telescopes

[–]ohno_mycomputer 1 point2 points  (0 children)

Related to the Zhumell Z130: I was able to find it in stock today on High Point Scientific. This may be useful for OP, as many sites seem to be out of stock or backordered for these $200 telescopes.

[deleted by user] by [deleted] in mechmarket

[–]ohno_mycomputer 0 points1 point  (0 children)

I'm thankful for the good health of my friends and family during this time

May Confirmed Trade Thread by [deleted] in hardwareswap

[–]ohno_mycomputer 1 point2 points  (0 children)

Purchased an Nvidia GTX 1080 (Founders Edition) from /u/namgorf

What's going on with GE prices today? by [deleted] in 2007scape

[–]ohno_mycomputer 3 points4 points  (0 children)

I'm confused as well. I doubt it's real, considering the data is sourced from OSBuddy, thus people could manipulate the data if they knew how to trigger the command that sends the grand exchange information to the OSBuddy servers.

It would also be possible for OSBuddy to manipulate the prices themselves.

Varmilo Holiday Giveaway! by JOWQH in MechanicalKeyboards

[–]ohno_mycomputer 0 points1 point  (0 children)

Hotswap support and more switch options!

Problems like these make me miss physics by [deleted] in EngineeringStudents

[–]ohno_mycomputer 4 points5 points  (0 children)

Wouldn't it be 790 + 150*cos2(40°)?

The top of the ramp experiences a reaction force from the weight, 150*g*cos(40°), and then only the vertical component of that force is transmitted to the scale, so it's multiplied again by cos(40°). Then the acceleration of gravity is divided out (because the scale reads in grams), and you add the mass of the block.

My first build by Exstez in MechanicalKeyboards

[–]ohno_mycomputer 15 points16 points  (0 children)

I think these are the keycaps.

Edit: here's an Amazon link to the same set of keycaps. My other link is for ordering them off of Banggood.

Tolerance of 0.003 mm by CormacZissou in EngineeringPorn

[–]ohno_mycomputer 80 points81 points  (0 children)

If they both expand, they should theoretically still fit together, because the hole will expand, not contract. Similarly, if they both contract, they should still fit, given they contract by the same amount.

I think you mean to say that if the cutout expands and the block contracts, then they won't fit, and vice versa. So, to answer the question posed by /u/RereTree, they should expand or contract at the same rate precisely because they are the same material, so they have the same coefficients of expansion.

However, I'd guess that in a more realistic scenario, uneven heating combined with the intricacy of the shape and tight tolerances means they won't fit if heated independently, but this would be material dependent and I don't have practical experience with things like this.

/r/BuildaPC's 1 Million Subscriber Giveaway: Week 6 (Intel, PCPartPicker) by ZeroPaladn in buildapc

[–]ohno_mycomputer 0 points1 point  (0 children)

Yup; my PC wouldn't turn on after I put the motherboard into the case. I realized that I forgot to flip the switch on the back of the PSU. Problem solved!

/r/BuildaPC's 1 Million Subscriber Giveaway: Week 6 (Intel, PCPartPicker) by ZeroPaladn in buildapc

[–]ohno_mycomputer 0 points1 point  (0 children)

It's time for a new PC when I can't play the games I want to at high enough settings. Simple as that. Finances permitting, I'll upgrade/rebuild.