The Astronomy hobby thread

[MBAtarga]

Originally Posted by Eric Hahl

I got out last night and captured more data on the Heart Nebula. 10.5 hours worth.

That is just incredible!

[Eric Hahl]

Thanks Mark!

[dad911]

Eric, I'm at a loss for words, other than "WOW".

[Eric Hahl]

Originally Posted by dad911

Eric, I'm at a loss for words, other than "WOW".

Thank you!

[masraum]

Good stuff, thanks for posting and keeping this thread going.

[Pazuzu]

Originally Posted by RNajarian

but I was wondering, is it possible to have my setup locate and real-time track (larger) Earth satellites in orbit with my computerized mount?

Technically, yes, the mount is 100% capable of tracking satellites.
2 problems:

1) The software isn't designed to run at speed like that. The 5SE (and nearly anything else out there) is limited to about 3 degrees per second at fast slew, which is an unstable speed. Fastest stable speed (fully controlled by encoder feedback) is generally 2 degrees per second. That means it would take 90 seconds to go horizon to horizon.

2) The software is designed to override the Earth's rotation, which is a simple calculation. Satellites travel in complex 2 dimensional directions, and the software inside the telescope really isn't up to the task. There is external software that can interact with or override the mount, but I'm not sure if there's any Sky Portal compatible stuff. For sure there's programs on the PC that can run via Nexremote or Stellarium or something.

You'll need for sure the 2 line ephemeris/ephemerides for any satellite, this is a series of numbers in a defined order that software uses to calculate the projection of the orbital parameters. With that, the software knows how to point and move to track a satellite, but it remains to be seen if something like the 5SE is stable enough to pull it off.

Here's an example for the ISS:
TWO LINE MEAN ELEMENT SET

ISS
1 25544U 98067A 19298.54632874 .00016717 00000-0 10270-3 0 9005
2 25544 51.6402 74.8919 0006900 187.3660 172.7390 15.50181118 35473

These number CHANGE and sometimes are not correct. Generally, satellite data is not publicly available, so the 2-line data is calculated from observations and the orbital parameters are then estimated. If a satellite makes a tiny course correction, the parameters might be significantly off afterwards.

The same 2-line data is used for comets and asteroids (and actually, for planets and the Moon...) so the Celestron technically can read them, but the software doesn't run at a high enough resolution or sample rate for satellites.

Finally, you won't see anything but a bright dot, even with the camera and tracking. The ISS is HUGE and it's only about the same apparent angular size as Jupiter under the best of conditions, most satellites would be un-resolved even with a telescope.
The other problem is that unlike planets and such, a satellite changes distance dramatically as it goes from the horizon to overhead to horizon. here's an example for the ISS on a particularly good overhead view:
Event Time Altitude Azimuth Distance (km) Brightness Sun altitude
Rises 18:48:10 0° 221° (SW) 2,344 1.1 -15.1°
Reaches altitude 10° 18:50:16 10° 224° (SW) 1,481 0.0 -15.6°
Maximum altitude 18:53:33 61° 305° (NW) 471 -3.4 -16.4°
Enters shadow 18:55:04 28° 17° (NNE) 802 -2.7 -16.7°

So, it changes between 470 kilometers at it's closes to 2300 kilometers away. At's 100 meters across at the largest measurement, so that is:
arctan (100/470,000)=44 acrseconds to arctan(100/2300000)=9 arcseconds.

All of this is why it's hard to find info on tracking satellites online. Most people who get into it build purpose built mounts with high speed steppers and homemade control systems.


Oh...you better have that that telescope alignment dead nuts on as well, everything is dependent on the software calculating the orbital parameters on the fly as referenced by the true position of the scope...

[Rusty Heap]

Whats this?

My Green circle marked in this compressed jpg. zoom in on Eric's original post for much better resolution.


What is this blue oval disk surrounding a white sphere ? a whole spiral galaxy?

[Eric Hahl]

I actually think it's just an artifact. That's right near a pulsating double, V482 CAS.

[Pazuzu]

It appears strongly in h-alpha on other images I've found, it appears to be a torus shape around that star. Probably unrelated, possibly a blob that becomes toroidal when imaged with the bright star in front of it, due to camera or processing effects.

You can see it here:
https://upload.wikimedia.org/wikipedia/commons/e/e3/Heart_Nebula.jpg
and here:
https://apod.nasa.gov/apod/image/1909/HeartNebula_Falls_2378.jpg

[masraum]

Originally Posted by Pazuzu

Finally, you won't see anything but a bright dot, even with the camera and tracking. The ISS is HUGE and it's only about the same apparent angular size as Jupiter under the best of conditions, most satellites would be un-resolved even with a telescope.

Mike, I will concede that you have probably forgotten far more about astronomy and telescopes than I know or probably ever will.

But....

You can absolutely see the shape and structure of ISS through a telescope. I have some 20x60 binoculars through which ISS is just a bright spot in the sky, but my old Zhummel 8" Newt/dob with a 25mm EP (48x) absolutely allowed me to see structure and form of ISS (it was really, REALLY hard to hand track that even when I probably had 120-140* of sky to track through).

Every other satellite that I've seen (more than a few, except Iridium flares) are nothing more than a tiny dot. It's always fun to have one scoot through your view when observing something else. I've also, since I now live in the heart of Houston, used Stellarium to specifically watch some satellites. Other than ISS, they look the same through a 20x60 binocular as they do through an 8" telescope at 200x.

[masraum]

Originally Posted by Rusty Heap

Whats this?

My Green circle marked in this compressed jpg. zoom in on Eric's original post for much better resolution.


What is this blue oval disk surrounding a white sphere ? a whole spiral galaxy?

I'm pretty sure that's "their" force field.

[Pazuzu]

Originally Posted by masraum

Mike, I will concede that you have probably forgotten far more about astronomy and telescopes than I know or probably ever will.

But....

You can absolutely see the shape and structure of ISS through a telescope. I have some 20x60 binoculars through which ISS is just a bright spot in the sky, but my old Zhummel 8" Newt/dob with a 25mm EP (48x) absolutely allowed me to see structure and form of ISS (it was really, REALLY hard to hand track that even when I probably had 120-140* of sky to track through).

I guess I meant than *other* than the ISS (which we've all seen photos of, transiting the sun, etc) every other satellite is tiny and will be unresolved. Even the ISS is only big enough to see something under somewhat idea situations (high overhead). Once you get something like his 5SE scope cranking away at a degree a second in two axis, the mount will be shaking enough that it might not even be able to resolve the ISS...

[masraum]

Originally Posted by Pazuzu

I guess I meant than *other* than the ISS (which we've all seen photos of, transiting the sun, etc) every other satellite is tiny and will be unresolved. Even the ISS is only big enough to see something under somewhat idea situations (high overhead). Once you get something like his 5SE scope cranking away at a degree a second in two axis, the mount will be shaking enough that it might not even be able to resolve the ISS...

Ah, ok, I assumed it was something that I wasn't understanding about what you were trying to say. I was pretty sure that would be the kind of thing that you would know.

I assume the best bet for something like this is a decent web cam where the EP would normally go, then track however you can.

The way that I did it that one time was cool for a 1 time thing, but otherwise not something to do repeatedly.

What you really need is something like the guns from the Millennium Falcon that you can sit in and track with a telescope mounted in place of a gun where you just sit in-place and the whole thing follows your object through the sky while you observe.

[Eric Hahl]

If you want to really zoom in, check this one out. Once loaded, click the image for full res.

https://cdn.astrobin.com/thumbs/BMZ1y7f5cPyI_16536x16536_6gOgJc-O.jpg

[Rusty Heap]

november must watch events



anyone up to getting photos of Mercury in full transit in front of the sun?



https://www.msn.com/en-us/news/science/3-astronomy-events-that-you-wont-want-to-miss-in-november/ar-AAJte44?li=BBnbfcL&ocid=mailsignout

[masraum]

Originally Posted by Rusty Heap

november must watch events



anyone up to getting photos of Mercury in full transit in front of the sun?



https://www.msn.com/en-us/news/science/3-astronomy-events-that-you-wont-want-to-miss-in-november/ar-AAJte44?li=BBnbfcL&ocid=mailsignout

Cool, I won't be able to photograph it, but I'll be off and if the weather permits, able to watch it through some solar binoculars that I bought before the partial solar eclipse from a couple of years ago.

I've always wanted to see Mercury but haven't, so this will be a cool opportunity.

[flatbutt]

Originally Posted by masraum

Cool, I won't be able to photograph it, but I'll be off and if the weather permits, able to watch it through some solar binoculars that I bought before the partial solar eclipse from a couple of years ago.

I've always wanted to see Mercury but haven't, so this will be a cool opportunity.

Just remember it is tiny, teeny tiny. It'll look like a pea crossing a pizza.

[masraum]

Originally Posted by flatbutt

Just remember it is tiny, teeny tiny. It'll look like a pea crossing a pizza.

Yep. I've enjoyed watching sunspots with the binoculars.

[Eric Hahl]

I'm gonna miss the transit. No solar equipment in my stable at this time.

[Pazuzu]

Originally Posted by Eric Hahl

I'm gonna miss the transit. No solar equipment in my stable at this time.

https://www.amazon.com/Thousand-Oaks-Optical-Telescopes-Binoculars/dp/B00DS7S52W