hha

I have a Jupiter 8 Type 4 50mm f/2 from 1982 with a Leica screw mount, which I mounted on a Nikon Z6. Very compact, but not as good as the Leica 50 mm f/2 Summaron (chrome pullout), but being ...

You got  the idea. You have to experiment where the stray magnetic field is coming from, and stay away from those area. In my case I only needed a 2" spacer made from wood. While the S22 compass ...

Very nice work. How many separate nights did you need for the 16 hours of integration? hha

I have gotten the polar alignment to within 1 degree in Elevation, 2 degree in Azimuth with this method.  The problem with Azimuth is the distortion of the magnetic field by your tracking device. ...

There is a dilemma: Other than for personal satisfaction, the only way amateur/hobby astronomers can make competitive pictures is using wide fields, 10x10 degree or bigger of star-scapes, like the ...

Your D5600a has the extended red response. This probably explains why M57 with your D5600a has a little reddish cast compared to the more blue with my stock D7200. Cheers, hha

Hi: Mario. Thanks for the screenshot. I rotated and scaled it to approximately match my image. Yes. M57 is resolved with your Sigma 105mm at f/2. Very impressive. cropped from 4000x6000 D7200, ...

Mario: Nice lens and lots of stars. Two days ago I took images of the Lyrae constellation with a 135mm lens, but I posted only a small crop (at full resolution with a D7200) of the Vega and ...

When stopped down a little, all lenses show a diffraction pattern (sun star) around bright stars. For some lenses the pattern is ugly, for other it can have an artistically pleasing effect. Shown ...

Thanks for the picture. It appears to cover a 3 degree area. To analyze your "No CA" comment I did some manipulations in PS. On the left is a picture of eps10/20 Lyrae cropped from your picture ...

Maybe a 200 or 300 mm lens would be a good starter for clusters and some of the bigger galaxies.  The longer and bigger lenses on your list require a lot of experience and $$$. hha

David: Interesting writeup. I have accidentally taken and processed series of defocused images. All but the faintest stars  tend to have magenta or cyan haloes, depending on  which side the focus ...

Yes, this 50 year old lens Nikkor 200mm Q f/4 lens, used at f/4. It has only four elements, and was corrected for only two colors, i.e. achromat. The challenge I proposed to the readers is to take ...

Tristimulus: Notice I said "colorful stars" not "star colors". Since we are not doing any science with these pictures, a little color thrown in, even if an artifact of the lens, does not hurt. You ...

I got tired of looking at colorful pictures of emission nebulae, so here is a colorful star pictyre. On the left is a  300x600 crop centered on  eps01/eps02 Lyrae, taken with a 50 year old Nikkor ...

The Earth rotates 360 degree in 24 hours = 15 degree/hour = 15 arcsec/sec.

Obviously, if your polar alignment is not perfect, you will get trails. How long a trail will you accept in your 1 minute exposure? How are you going to process the data afterwards? Here is my ...

Very nice result  of M13. What caused you to limit the exposure to 120 sec per shot? hha

For a 24 Mp camera the rule of 500 is way to slow. The first picture, which shows the moon emerging from the hillside at about 12 degree elevation, was taken from a fixed tripod with the 200mm ...

For those who got clouded out Nikkor 200mmQ f5.6 iso200 10 sec StarTracker. Enjoy. hha