So You Wanna Buy a Telescope: Advice for Beginners (2015) • Hacker News Board

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#91

Post by aortega » Tue, May 24, 2016, 1:56 AM UTC

dr_zoidberg wrote: post #77

madaxe_again wrote: post #64

Earlier quoted context omitted.

There's astrophotography and then there's astrophotography, however - and you get drawn deeper and deeper into it. I have a few scopes, but mostly use an 8" celestron schmidt-cassegrain - it's a decent all-rounder for astrophotography, particularly as I mostly do deep sky stuff. I started with a simple T-adapter and a DSLR, and of course, you start as you describe playing with the exposure, the iso - but then you wan…

About capturing a bit more fo that dim halo, I always wondered... Wouldn't a secondary scope (with similar characteristics) result in an increased light gathering potential? I've also tried to look into visible-light interferometry, but there aren't many accessible resources on the subject. My feeling is that there is a point in equipment in which you are simply better off getting a new rig (to work in paralell) than…

But you also need another camera and probably another mount too. The scope is actually the cheapest component in a astrophotography setup. Probably the 80% of the cost is the mount+the camera.

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#92

Post by [deleted] » Tue, May 24, 2016, 1:56 AM UTC

dr_zoidberg wrote: post #77

madaxe_again wrote: post #64

Earlier quoted context omitted.

There's astrophotography and then there's astrophotography, however - and you get drawn deeper and deeper into it. I have a few scopes, but mostly use an 8" celestron schmidt-cassegrain - it's a decent all-rounder for astrophotography, particularly as I mostly do deep sky stuff. I started with a simple T-adapter and a DSLR, and of course, you start as you describe playing with the exposure, the iso - but then you wan…

About capturing a bit more fo that dim halo, I always wondered... Wouldn't a secondary scope (with similar characteristics) result in an increased light gathering potential? I've also tried to look into visible-light interferometry, but there aren't many accessible resources on the subject. My feeling is that there is a point in equipment in which you are simply better off getting a new rig (to work in paralell) than…

[deleted]

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#93

Post by aortega » Tue, May 24, 2016, 1:57 AM UTC

vvanders wrote: post #70

madaxe_again wrote: post #64

Earlier quoted context omitted.

There's astrophotography and then there's astrophotography, however - and you get drawn deeper and deeper into it. I have a few scopes, but mostly use an 8" celestron schmidt-cassegrain - it's a decent all-rounder for astrophotography, particularly as I mostly do deep sky stuff. I started with a simple T-adapter and a DSLR, and of course, you start as you describe playing with the exposure, the iso - but then you wan…

Yup, no idea what GP is talking about, most dobs aren't really great for AP since the focal plane isn't in the right location. I'm a huge photo-nerd but I took one look at AP and was like "nope!" for the exact above reasons + extremely long capture times. We're talking hours of frames to see some things.

It's mostly automated.

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#94

Post by [deleted] » Tue, May 24, 2016, 1:57 AM UTC

vvanders wrote: post #70

madaxe_again wrote: post #64

Earlier quoted context omitted.

There's astrophotography and then there's astrophotography, however - and you get drawn deeper and deeper into it. I have a few scopes, but mostly use an 8" celestron schmidt-cassegrain - it's a decent all-rounder for astrophotography, particularly as I mostly do deep sky stuff. I started with a simple T-adapter and a DSLR, and of course, you start as you describe playing with the exposure, the iso - but then you wan…

Yup, no idea what GP is talking about, most dobs aren't really great for AP since the focal plane isn't in the right location. I'm a huge photo-nerd but I took one look at AP and was like "nope!" for the exact above reasons + extremely long capture times. We're talking hours of frames to see some things.

[deleted]

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#95

Post by aortega » Tue, May 24, 2016, 1:58 AM UTC

CydeWeys wrote: post #58

aortega wrote: post #29

I disagree with the astrophotography thing. Even with a telescope your human eyes are limited to planets and the moon, that's it. Forget about seeing galaxies with the naked eye, unless you have a 1-meter diameter telescope. All other objects are basically points of light. Artificial satellites are really fun to see, but also points of light. But a 2006 DSLR (EOS400) that I found in the garbage, connected to a cheap…

You are severely hurting your argument by making false statements about what is possible to see with the naked eye and what kind of diameter telescope is required. An 20cm reflector is a very reasonable telescope that won't break the bank, will fit into most cars, and will enable you to see a large number of galaxies and nebulae with the naked eye. The claim that you need a 100cm telescope to do so is ludicrous and c…

Which galaxies? Andromeda maybe. I'm talking of a city or suburban environment. Of course if you go really far into the forest, you can see a galaxy. But it's a hassle, how many times a year you can do that?

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#96

Post by aortega » Tue, May 24, 2016, 2:01 AM UTC

cosmeen wrote: post #68

aortega wrote: post #29

I disagree with the astrophotography thing. Even with a telescope your human eyes are limited to planets and the moon, that's it. Forget about seeing galaxies with the naked eye, unless you have a 1-meter diameter telescope. All other objects are basically points of light. Artificial satellites are really fun to see, but also points of light. But a 2006 DSLR (EOS400) that I found in the garbage, connected to a cheap…

Do you have any photos uploaded somewhere public?

yes, https://www.astrobin.com/users/aortega/

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#97

Post by aortega » Tue, May 24, 2016, 2:04 AM UTC

LoSboccacc wrote: post #46

aortega wrote: post #29

I disagree with the astrophotography thing. Even with a telescope your human eyes are limited to planets and the moon, that's it. Forget about seeing galaxies with the naked eye, unless you have a 1-meter diameter telescope. All other objects are basically points of light. Artificial satellites are really fun to see, but also points of light. But a 2006 DSLR (EOS400) that I found in the garbage, connected to a cheap…

sure a robot mount and photo stacking changes everything, but makes the entry price jump from 500$ top to 2k$, which would just turn down any beginner

Photo stacking software is free.

A very good robot mount plus telescope can be had for 800 us$ (Nexstar 6SE)

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#98

Post by acqq » Tue, May 24, 2016, 8:16 AM UTC

spdustin wrote: post #82

acqq wrote: post #48

Earlier quoted context omitted.

For those who don't know, this is what's possible without the telescope and the camera you can use for the other photos too: https://www.flickr.com/photos/119551085@N06/15418169222/in/a... Just Sony NEX-6, a tripod and 30 seconds on the (carefully selected) convenient place. Using image stacking software is also a fantastic tip, big thanks to the sibling comments.

Just that camera, stacking software, and the driest, darkest place on Earth (slight exaggeration) the Atacama Desert. Excellent photo, though. I'd love to visit a site with such dark skies and good seeing.

Would stacking work for that photo at all? Wouldn't the features on the ground be blurred if you align the stars?

I could believe it's just ISO 1600 and 30 seconds, as the EXIF says?

And you don't need to travel to Chile, just be away from the light pollution and be prepared to make the photos during the moonless night. Use the shooting timer and then you can even have a video of the stars moving, the Milky Way is always impressive:

https://www.youtube.com/watch?v=ZwzY1o_hB5Y

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#99

Post by dr_zoidberg » Tue, May 24, 2016, 2:29 PM UTC

aortega wrote: post #91

dr_zoidberg wrote: post #77

Earlier quoted context omitted.

About capturing a bit more fo that dim halo, I always wondered... Wouldn't a secondary scope (with similar characteristics) result in an increased light gathering potential? I've also tried to look into visible-light interferometry, but there aren't many accessible resources on the subject. My feeling is that there is a point in equipment in which you are simply better off getting a new rig (to work in paralell) than…

But you also need another camera and probably another mount too. The scope is actually the cheapest component in a astrophotography setup. Probably the 80% of the cost is the mount+the camera.

Absolutely. Then again, there are limits. I remember an old Meade model (no longer available) that was a 20", $36k monster. I was beautiful, and they sold it as an observatory-grade instrument. But the 16" models were priced close to $10k, so it sort of made sense (in that particular case) to duplicate the rig. My "napkin analysis" was:

20" diameter, ~315 squared inches of area[0], $36k

2x 16 inches diameter, ~402 squared inches of area, $20k

This prices did include mounts, but back then (more than 10 years ago) I wasn't very knowledgeable and I honestly don't know if they were good mounts. So there was margin to increase the light gathering and having spare money for the new camera.

Still, the most interesting use for multiple telescopes would be building and interferometer. I'll keep looking into that, with the procesing power available in todays machines it should be doable.

[0] I know the secondary mirror obstructs the light gathering, but I don't have precise figures, so let's go with it the area of the main mirror.

Re: So You Wanna Buy a Telescope: Advice for Beginners (2015)

#100

Post by OpenDrapery » Tue, May 24, 2016, 5:29 PM UTC

I am looking at buying a telescope that I can mount to my son's playhouse, and leave it outside year around. We live in the midwest, so there is weather.

I was thinking of something like the coin operated ones that you see at tourist spots. They are pretty expensive. Anyone have any info or done something like this before?