Josh Meyers

Hacking on this at DESC2017. I've got a Hopkins-basis aberrations generator built. Here's an image showing how it generates a field-dependent PSF (highly defocused LSST donuts in this case): ![hopkins...

Hopkins basis = double Zernike basis. So, for example, the way that the wavefront spherical aberration coefficient (Z11) varies over the field of view is itself described as a linear...

Applying extinction to an SED should be as simple as multiplying it by a function of wavelength, I think, which is already supported. I'd be happy to see some methods...

> As Josh said, this is already possible by multiplying the object by a function: > > ``` > gal_raw = chromatic_disk + chromatic_bulge > gal_obs = gal_raw * extinction_function...

Hi @rmandelb, I think multiplying a `ChromaticObject` by a function of wavelength probably will accomplish what a user expects, it's just inconsistent with `__div__`, and the multiplier gets stored in...

I figured :), but thought it was worth raising the question: should we actively try to catch and raise an exception if you try to multiply a `ChromaticObject` by an...

I'd vote for option 2 for two related reasons: 1. Dimensionally consistent. Although `SED` can accept input proportional to any of erg/nm, erg/Hz, or photons/nm, it always keeps an internal...

I thought about that. The only awkward part is that then `UniformDeviate` will have an inherited method `.poisson` and so on. Maybe that's fine though.

> How relevant are the analytic ones, considering that they ignore pixel convolution? I think we can leave the pixel convolution up to the user: ``` python gal = galsim.Gaussian(half_light_radius=1)...

Err. Just noticed that the `Piff.Star` objects we attached here are exactly 21x21 pixel stamps. So it's not unreasonable for Piff to fail to extrapolate to 25x25 (though maybe that'd...