Bob in Baltimore

Ah! Here is the problem. Moving from a full frame to a crop sensor does not change the effective focal length of the lens, even tho people often speak in those terms. When you move from a full ...

I believe that your EFL is 560 mm, not 840 mm with a 1.4 x Barlow & a 400 mm zoom. Even so, I would expect better detail than you are showing. My guess is that you are loosing IQ by shooting your ...

Astonishingly good image! Nice work.

Amusing. This brought a smile to my face. Thanx.

I have been using the DawnTech GPS with my D850 for several years. It is fantastic! Easy to use, rapid satellite acquisition, accurate, and not a significant drain on the camera battery. See   ...

I'm not sure if the good answers already given are actually answering the question you have. Is your question really about figuring out what the Milky Way will look like from any particular place ...

Your question about Mercury brings to mind the story that the craters on Mercury were actually observed in 1901 by Dr Thomas Jackson Jefferson See, using the 26" telescope of the U. S. Naval ...

Thanx. It helps that the D850 is a very low noise camera, and it helps that the sky is really really dark at Mauna Kea, even at a mere 9,200 feet. I wish that I had spent more time on Orion, but my ...

This composite was made from a stack of 341 1/2 second images processed using PixInsight and Photoshop. I used my Nikon D850 with a rented Nikon 200 mm f/2 lens at f/4 & ISO 1600. It was shot from ...

How can I take a slideshow prepared in Fotomagico 5 and make it suitable for folks with PCs? It seems an obvious question but I cannot find an answer in their documentation or through a general ...

The Question I had: I have just installed RawTherapee on my iMac (late 2014) running OS 10.14 Mojave. It will not run. When I try double clicking it on the disk image the OS says the app can't be ...

Thanx for the great tip. I knew how to open a single preview with the space bar ... but wow! Bob

Thinking strictly in  terms of pixels on the target. this is correct. But the difference is not as large as you might think. The Nikon D500 has a pixel size of 4.2 microns. not a big advantage ...

<snip> I think that the camera/eyepiece analogy can lead you astray. Magnification has no real useful meaning here. The magnification a simple lens is M = f/(f-d(Obj) ) where f is the focal length ...

Stunning!

Duh! Sorry for the dumb response. My brain was not engaged. Good question. I look forward to seeing some good answers.

That looks like bracketing to me.

You need to add to your initial post on the astrophotography forum. Your question was very general and difficult to answer other than by asking more questions of you. There is a lot of expertise ...

Clever! And very nice. It brought to mind a song sung by Perry Como in the fifties  - "Catch a falling star and put it in your pocket". (Bad astronomy I know, but my imagination doesn't know any ...

Really like how you handled the sky in your reponse. What is the " intelligent brush tool" of which you speak.