The Astronomy hobby thread

[Eric Hahl]

Two screw secondary collimation?...hows that work?

[Pazuzu]

Originally Posted by Eric Hahl

Two screw secondary collimation?...hows that work?

Center screw holds the assembly in place, 2 screws 90 degrees apart for collimation, with a spring across from each screw to compensate. So, tip-tilt correction instead of 3 point triangle correction.

[Eric Hahl]

Kinda figured something like that.

[Eric Hahl]

Captures from the last two nights...

[masraum]

Very nice! I always love looking at AP photos. It's amazing to see a galaxy, but then whats even more amazing (besides the central subject) is when there are other galaxies in the background of the photo.

[masraum]

Some cool stuff from the Hubble









One of the really amazing things about Hubble images is how almost everyone has anywhere from a few to a bunch of galaxies in the distant background. So while the main subjects are galaxies that we "know" of, in the background there may be another 5, 10, or 50 other distant galaxies that we've likely never seen before.

[flatbutt]

The physical scale of that reality just makes my head hurt.

[Eric Hahl]

More like 10s of thousands. The longer the exposure the more galaxies start to show up.

[masraum]

Yes, the deep field was amazing.

[flatbutt]

I expect that Webb will truly blow our minds.

[Eric Hahl]

Originally Posted by flatbutt

I expect that Webb will truly blow our minds.

Indeed!

[Scott Douglas]

It really begs the question of how big is BIG, doesn't it.

[Eric Hahl]

100s of billions of galaxies with 100s of billions of stars in each one and probably each containing billions of planets. Mind bending.

[flatbutt]

Have you ever tried to imagine what lies beyond the beginning of space? What if Webb can see back to the "Big Bang"? What would lie beyond that? Oh my aching head.

[Eric Hahl]

Woohoo! I added another scope to the mix. This is a William Optics FLT-120. Should be great for general purpose Astro Photos.

Aperture: 120mm
Focal length 780
F/R: F6.5

I picked this size for its portability factor. Didn't want to lug around a 130 and wanted a bit more resolution than a 100 could give. Can't wait to try it out.

[masraum]

Originally Posted by Eric Hahl

Woohoo! I added another scope to the mix. This is a William Optics FLT-120. Should be great for general purpose Astro Photos.

Aperture: 120mm
Focal length 780
F/R: F6.5

I picked this size for its portability factor. Didn't want to lug around a 130 and wanted a bit more resolution than a 100 could give. Can't wait to try it out.

Super nice scope!

What's the size difference between the 120 and 130 (besides 10mm on the objective)?

I know that when you increase diameter, the area/volume increases exponentially, but I still wouldn't have thought that there'd be that much difference between a 120 and 130 (assuming similar focal ratio).

[Eric Hahl]

Thanks, yes, seems 10mm isn't so much but it more the weight of the objective and the overall focal length. A 130F7 scope has a native fl of 910mm. You can add a reducer to make it an 728mm f5.6 but that's just adding more glass to the mix.

This one is where I want to be without adding a reducer at 780mm.

Guess I should clarify. I will be adding a field flattener to this setup so in essence I'll be adding more glass. However, the field flattener is sharper than the focal reducer/flattener combo.

Also, this scope is 15.8 lbs, a similar 130 is about 20. The less weight on the mount the better.

[masraum]

Originally Posted by Eric Hahl

Thanks, yes, seems 10mm isn't so much but it more the weight of the objective and the overall focal length. A 130F7 scope has a native fl of 910mm. You can add a reducer to make it an 728mm f5.6 but that's just adding more glass to the mix.

This one is where I want to be without adding a reducer at 780mm.

Guess I should clarify. I will be adding a field flattener to this setup so in essence I'll be adding more glass. However, the field flattener is sharper than the focal reducer/flattener combo.

Also, this scope is 15.8 lbs, a similar 130 is about 20. The less weight on the mount the better.

Ok, so not a huge size difference, but sure different focal length (I can see that shorter is probably better for AP as a rough generalization), and weight, but not tons of weight. It sounds like it's more about functionality and the mount handling the weight than size and you having to lug it around. Got it.

[Eric Hahl]

Of course, Astro-Physics makes 130mm @ F6 (my dream scope) so that would equal the same 780mm focal length as my 120. However, its over twice the price and has about a 10 year waiting list.

[flatbutt]

Originally Posted by Eric Hahl

Woohoo! I added another scope to the mix. This is a William Optics FLT-120. Should be great for general purpose Astro Photos.

Aperture: 120mm
Focal length 780
F/R: F6.5

I picked this size for its portability factor. Didn't want to lug around a 130 and wanted a bit more resolution than a 100 could give. Can't wait to try it out.

IDK how much experience you have with WO but I think you're going to be very pleased.

I bought the GTF 102 for its' portability and was very happy that the quality of the optics lived up to the reviews.