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Equipment Discussions >> Mounts

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Hilmi
Post Laureate
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: 10Micron new [Re: korborh]
      #6312094 - 01/14/14 11:24 AM

Quote:

Good points Orly. I expect closed loop guiding with OAG to be significantly better than any open loop unguided model based tracking, especially with long FL Reflectors.
Per, what is the FWHM of the stars in arcsec in your unguided exposure? Without this number it is hard to say what you are trading off by doing unguided. And I am sure you can do better guided.
Unguided seems very useful for short exposures, photometry, supernova hunting etc. type of work. But for serious high-res long exp imaging, a real star based feedback from OAG closed loop guiding is the way to go.




Or maybe encoders and an AO unit are the way to go.


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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: 10Micron new [Re: Hilmi]
      #6312164 - 01/14/14 11:59 AM

Hilmi - stop! Stop! Too many options! My. Brain. Will. Explode!

Okay, someone please test all of these options for me, right away, please.... And with as many different high-end mounts as possible.

Paul


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: 10Micron new [Re: psandelle]
      #6312198 - 01/14/14 12:16 PM

Sure send me the money for expenses and I'll do all the testing you need

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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: 10Micron new [Re: Hilmi]
      #6312217 - 01/14/14 12:24 PM

Hahahahaah! You're killin' me!

Still, one day someone's going to do the tests, and we'll get a more accurate idea of where the extreme points are in the data...FL beyond this, subs beyond that, etc. That'll make choosing a mount a little less guesswork.

Paul


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: orlyandico]
      #6312225 - 01/14/14 12:27 PM

Quote:

Definitely running unguided is much more fun than guided, iff the results are the same.

However: I think guided will outperform unguided at small pixel scales and long exposures on a mount with no encoders. If you look at SB's ProTrack page (https://www.bisque.com/help/paramountme/what_is_protrack.htm), they show some images at modest pixel scales (1.56"/pixel).

I think if you're down in the weeds at say 0.4"/pixel then properly-working OAG will outperform unguided with mount modeling. It definitely would on an encoder-less mount. On a mount with encoders? I don't know, but I would guess yes.

Per keeps mentioning his 1 hour long unguided but that's at 1m focal length. I'm thinking his pixel scale is > 1"/pixel, probably closer to 1.5"/pixel.




I can't really imagine that any mount, regardless of how good the construction, how high resolution the encoders, how precise the model, will not at some point benefit from the use of a guider or AO unit. It all depends on the target, pixel scale, etc. and will sooner or later be impacted negatively by atmospheric conditions, unmodeled flexture, etc. Once you get to this point, then some kind of additional help will be necessary, although it may very minor in the scheme of things. But this is why every premium mount out there, regardless of how well it can do unguided imaging, can also be guided. I really can't imaging someone selling a premium imaging mount that can never be guided or integrated with an OA unit. These things simply are not magic. Of course, once we call all set up our own remote telescopes on the moon, then the game will change a bit.


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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: 10Micron new [Re: EFT]
      #6312240 - 01/14/14 12:36 PM

Ed - when I buy a mount from you for my moon-based remote telescope, will you being doing onsite setup?

Paul


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: psandelle]
      #6312260 - 01/14/14 12:48 PM

Quote:

Hahahahaah! You're killin' me!

Still, one day someone's going to do the tests, and we'll get a more accurate idea of where the extreme points are in the data...FL beyond this, subs beyond that, etc. That'll make choosing a mount a little less guesswork.

Paul




There's a few problems with getting the testing information that we all want. The first is that when you own the equipment, the last thing you want to be doing with it is a running a bunch of tests for other people to see. You want to be out there making observations and getting to the end-product images. You don't exactly spend all this money as a community service after all.

The second is that, if the manufacturers, dealers or anyone connected to the product does the test, no one believes the results.

Finally, independent testing from magazines is simply very limited and even those results are often questions based the publications accepting advertising dollars.

Kind of a Catch 22 until you find someone who is will to spend a bunch of time just producing a load of data for other people.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: psandelle]
      #6312263 - 01/14/14 12:50 PM

Quote:

Ed - when I buy a mount from you for my moon-based remote telescope, will you being doing onsite setup?

Paul




Love to, but the travel and expenses bill might add a bit to the cost.


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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: 10Micron new [Re: EFT]
      #6312370 - 01/14/14 01:56 PM

Quote:

Quote:

Ed - when I buy a mount from you for my moon-based remote telescope, will you being doing onsite setup?

Paul




Love to, but the travel and expenses bill might add a bit to the cost.




how long is the drive to LA from phoenix?


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GIR
super member


Reged: 01/02/10

Loc: Finland
Re: 10Micron new [Re: Pinbout]
      #6312529 - 01/14/14 03:18 PM

I thought this was a thread about 10Micron?

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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: 10Micron new [Re: GIR]
      #6312547 - 01/14/14 03:21 PM

Quote:

I thought this was a thread about 10Micron?




I would love a 10micron mount

did you hear it?

neither did I, its so quiet.


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frolinmod
Carpal Tunnel


Reged: 08/06/10

Loc: Southern California
Re: 10Micron new [Re: korborh]
      #6312665 - 01/14/14 04:08 PM

Quote:

Unguided seems very useful for short exposures, photometry, supernova hunting etc. type of work.



Exactly. That's what robotic mounts are all about. If you're doing patrol work, you're hitting so many targets each night that you don't have night time to waste on letting a guider settle in before each exposure. The ability to do five minutes or so unguided is a godsend there.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: Pinbout]
      #6312677 - 01/14/14 04:15 PM

Quote:

Quote:

Quote:

Ed - when I buy a mount from you for my moon-based remote telescope, will you being doing onsite setup?

Paul




Love to, but the travel and expenses bill might add a bit to the cost.




how long is the drive to LA from phoenix?




Five to six hours.


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Per Frejvall
sage


Reged: 09/28/12

Loc: Saltsjöbaden, Sweden
Re: 10Micron new [Re: EFT]
      #6313569 - 01/15/14 01:41 AM

My one-hour came out at about FWHM 3". It is not a reliable measurement as the stars are severely burned, though. The -3dB point (not exactly astro speak, but...) of a burned star is really way out there towards the edge of it.

When I do not burn stars (that would be a hobby) and instead expose properly I get FWHM values on par with the seeing, regardless of exposure time, but using only fast scopes means I do not do much more than half-hour subs regardless of targets. Usually it is 20 minutes of narrow-band and that's about as long as I need.

The idea of an AO unit in unison with an encoder mount that can track "forever" is an attractive one. I have yet to try it. One more thing to buy - as if I didn't have enough stuff in the closet already.

As for time to test, I can say that I enjoy testing very much, but I still prioritize imaging. The weather in Sweden isn't always top notch and this fall and start of the winter has been impressively unproductive. I set my hopes to my remote setup in Provence, but the weather has been *BLEEP* there too the past couple of weeks.

/per


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Per Frejvall
sage


Reged: 09/28/12

Loc: Saltsjöbaden, Sweden
Re: 10Micron new [Re: Per Frejvall]
      #6313579 - 01/15/14 01:52 AM

Here's an unguided M33 just to keep the thread pretty.

M33, LRGB, GM2000HPS, Tak FSQ-106EDX III, SBIG ST-8300M, Baader filters, from the balcony 14 km from downtown Stockholm (big forest between me and Stockholm helps, but still).

/per



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dawziecat
Carpal Tunnel
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Reged: 10/20/10

Loc: Rural Nova Scotia
Re: 10Micron new [Re: Per Frejvall]
      #6313778 - 01/15/14 07:18 AM

That's a very pretty M33.
I had not thought it a very suitable target for the FSQ/ST-8300M, both of which I use.
I will reconsider.


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Per Frejvall
sage


Reged: 09/28/12

Loc: Saltsjöbaden, Sweden
Re: 10Micron new [Re: dawziecat]
      #6313811 - 01/15/14 07:52 AM

Thanks. It is all about image scale, isn't it? How does a galaxy of that size look with half an arcsecond per pixel? Not so pretty

/per


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guyroch
Vendor (BackyardEOS)
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Reged: 01/22/08

Loc: Under the clouds!
Re: 10Micron new [Re: Per Frejvall]
      #6313836 - 01/15/14 08:16 AM

Quote:

Here's an unguided M33 just to keep the thread pretty.




Is this a 60 minutes exposure just like the other one you posted a few days ago?

Guylain


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: Per Frejvall]
      #6314065 - 01/15/14 10:27 AM

Quote:

Thanks. It is all about image scale, isn't it? How does a galaxy of that size look with half an arcsecond per pixel? Not so pretty

/per




What is the pixel scale of that image?


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: 10Micron new [Re: guyroch]
      #6314081 - 01/15/14 10:37 AM

Quote:

Quote:

Here's an unguided M33 just to keep the thread pretty.




Is this a 60 minutes exposure just like the other one you posted a few days ago?

Guylain




We will have to see what Per has to say, but I'm sure that it is not a 60 minute, single sub image. The problem with very long subs, guided or unguided, is that they get blown out with very bright objects and stars. Longer exposures may be useful with certain filters and very dim objects, but in most cases very long single exposures are more academic than useful. Its that 10 to 30 minute zone that most people really need and where an unguided mount really needs to do well for normal imaging. The people that I recall asking for the ability to go much longer than 20 to 30 minutes were not doing normal imaging but instead more scientific stuff like spectroscopy if I remember correctly.


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