Lee Jay
Pooh-Bah
   
Reged: 02/27/08
Loc: Westminster, CO
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Re: Jason Ware's LX800
[Re: Peter in Reno]
#5562355 - 12/09/12 12:27 PM
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What about narrow band imaging? It usually requires a significantly longer sub exposure at a minimum of 15 minutes up to 30 minutes. NB imaging is getting very popular especially for light polluted skies.
Peter
Good point.
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galaxy_jason
Vendor
Reged: 05/22/07
Loc: Texas
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Re: Jason Ware's LX800
[Re: Lee Jay]
#5562612 - 12/09/12 03:04 PM
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Look at my web site. I do 10 minute subs at f8 from Dallas in HA, SII and OIII. 30 minute subs are not needed.
One thing I forgot to mention, on both mount samples I have seen so far the declination backlash is almost non-existent
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ahopp
sage
Reged: 05/24/12
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Re: Jason Ware's LX800
[Re: galaxy_jason]
#5563784 - 12/10/12 09:09 AM
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Great work Jason.
Tony
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Starhawk
Post Laureate
Reged: 09/16/08
Loc: Tucson, Arizona
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Re: Jason Ware's LX800
[Re: freestar8n]
#5564716 - 12/10/12 06:58 PM
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I was trying not to go there, but if one were trying to conceal tracking errors, far southern targets and big, blobby stars are a good start.
-Rich
Quote:
The measure of a well guided image at long focal length isn't just "round" stars, but small and round stars. If the stars are large and round, it could be due to poor focus and/or guiding, and the size of the stars will mask both flexure and field curvature. If the stars are very small, then the effects of flexure and field curvature become much more noticeable.
Regarding OAG, I think it is essential if you want to realize the full potential of a large aperture sct. I don't think it could be easily offered in some automated form, mainly because of the difficulty in maintaining focus on the guide chip. At the same time it is not that difficult to use once the system is configured, particularly with a sensitive ccd guide camera and a smooth mount that can tolerate long guide exposures.
Regarding the helix image - I have never imaged it myself because it is at -20 declination, and not an easy target from mid-northern latitudes. Even from Dallas it's an odd choice if seeing conditions aren't optimal, and the other examples of pac-man and crab make more sense.
Frank
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Lee Jay
Pooh-Bah
   
Reged: 02/27/08
Loc: Westminster, CO
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Re: Jason Ware's LX800
[Re: Starhawk]
#5564847 - 12/10/12 08:29 PM Attachment (42 downloads)
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I was trying not to go there, but if one were trying to conceal tracking errors, far southern targets and big, blobby stars are a good start.
This is a tight crop of one of Jason's images. Does this meet the criteria you expressed above?
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Mkofski
professor emeritus
   
Reged: 07/19/11
Loc: Greenfield, Indiana, USA
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Re: Jason Ware's LX800
[Re: Starhawk]
#5564870 - 12/10/12 08:42 PM
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Rich,
Think you should have tried harder not to go there. I'm not sure what would be gained for Jason or for Meade if the results were not on the level. With all the problems with the LX800 early this year a second round of bad results would be the end of the product... IMO.
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galaxy_jason
Vendor
Reged: 05/22/07
Loc: Texas
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Re: Jason Ware's LX800
[Re: Mkofski]
#5564961 - 12/10/12 09:42 PM
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Yep, that's it. I picked low targets to get big blobby stars to hide tracking errors. As they say on Monday night football. Come on man.
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David Pavlich
Transmographied
   
Reged: 05/18/05
Loc: Mandeville, LA USA
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Re: Jason Ware's LX800
[Re: Starhawk]
#5565004 - 12/10/12 10:19 PM
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Time for a cool off. It's locked for the time being.
David
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David Pavlich
Transmographied
   
Reged: 05/18/05
Loc: Mandeville, LA USA
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Re: Jason Ware's LX800
[Re: Lee Jay]
#5565709 - 12/11/12 10:47 AM
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Unlocked. Let's see if we can behave.
David
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ahopp
sage
Reged: 05/24/12
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Re: Jason Ware's LX800
[Re: David Pavlich]
#5565714 - 12/11/12 10:56 AM
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Jason,
Can you compare the performance so far with the LX800 to other platforms you have used? I am a patiently waiting recall customer of the 14".
Tony
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freestar8n
Carpal Tunnel
   
Reged: 10/12/07
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Re: Jason Ware's LX800
[Re: Starhawk]
#5565758 - 12/11/12 11:22 AM
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I only mentioned the low dec. of Helix because someone had requested comparison images. My note prior to that request had specifically pointed to my comparison image of the Crab, and at the same site I additionally have images of Pac-man - and many others. So regarding the specific request for comparison helix images - it is not as common or popular a target from mid-northern latitudes as many other options.
For comparing one system to another in terms of guiding and so forth, I place more value on 1) fwhm in arc-seconds, 2) raw, linearly stretched sub-exposures, and regarding flexure, 3) a measured rate in arc-sec/minute of the flexure. This can be determined from successive plate solves of the sub-exposures directly - assuming no polar rotation. And for best results that capture the guiding capability of the system, I would use an object up from the equator but not too far, so it is in steadier atmosphere but not so far from the equator that it is moving slowly across the sky.
I don't think these are unreasonable things to request since I provide similar information to convey my own autoguiding results. I also provide a video-based tool for realtime analysis of flexure rates - as a free download. A typical sct flexure rate with a guidescope might be 0.1-0.3" per minute - which is tolerable in a 5-minute exposure if the stars are perhaps 4" in diameter, but when they are 2" it becomes a problem that limits exposure time. I don't concern myself with flexure much since I switched to OAG.
For a refractor, flexure tends to be much smaller, and it is harder to get 2" stars in the first place - which is why I thought a refractor, using starlock on lx800, might be a better setup for someone who wants a turn-key imaging system that captures results close to the limit of the optics used.
Frank
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Starhawk
Post Laureate
Reged: 09/16/08
Loc: Tucson, Arizona
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Re: Jason Ware's LX800
[Re: freestar8n]
#5566021 - 12/11/12 02:09 PM
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My comment was geared towards producing an engineering test of the mount. The emotionally charged response isn't relevant to the issue at hand: performing an unambiguous evaluation of the LX800.
And since this is a second bite at the apple, it's got to hold up.
So, whatever OTA is required to get an image sharp enough to tell if it's tracking needs to be on there. And if that isn't Meade brand, then get ahold of whatever is needed. Evaluation of the ACF can be done separately.
The second item is point at some stuff along the equator requiring long integrations so tracking is obvious.
And yes, do both of these in the same image.
But trying to talk around doing sensitive evaluations or claiming hurt feelings isn't productive.
Because, at the end of all this, there isn't a third bite at the apple. And that's why I'm being critical.
-Rich
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galaxy_jason
Vendor
Reged: 05/22/07
Loc: Texas
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Re: Jason Ware's LX800
[Re: Starhawk]
#5566310 - 12/11/12 05:06 PM
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Accusations of falsifying data will get an emotional repsponse.
Last night was a little better seeing, not great, around 2" best focus. I also got a chance to try the latest firmware. This included some PEC updates and Starlock initialization updates.
Here is a 5.5 hour HA Rosette shot. The starlock tracking is essentially perfect. For the pixel peepers, you will see a very slight (about 1 pixel which is .77 arc seconds) diagonal elongation at the center of the frame. I believe this is the last bit of differential flexure. Not bad for a Cat.
Keep in mind this is an undprocessed image. Just combined then a slight stretch in PS. Many masterpieces you see on the net are deconvolved, dark overlay trailing reduced, etc.
http://galaxyphoto.com/tmp_800/rosett_5.5.jpg
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n2dpsky
member
Reged: 05/01/12
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Re: Jason Ware's LX800
[Re: galaxy_jason]
#5566375 - 12/11/12 05:59 PM
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I asked for comparison shots because it's very easy for people to be critical of others work when their's isn't subject the same sort of evaluation. I think some on the group are very interested in a positive discussion, but when others question the integrity of one of the foremost astrophotographers that I am aware of, I think that reveals their true intent, which is to bash Meade and anyone who works with them. Star hawk, are you even in the market for this scope? You're at a low latitude there in Tuscon. Can we see your Helix shot? I'd like to offer my opinion.
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andysea
professor emeritus
   
Reged: 09/03/10
Loc: Seattle, WA
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Re: Jason Ware's LX800
[Re: galaxy_jason]
#5566402 - 12/11/12 06:20 PM
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Great photos Jason! What is the native PE and guided RMS of the mount?
Thanks Andy
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Lee Jay
Pooh-Bah
   
Reged: 02/27/08
Loc: Westminster, CO
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Re: Jason Ware's LX800
[Re: galaxy_jason]
#5566404 - 12/11/12 06:21 PM
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Thanks for the sample, Jason.
I have several questions.
What was the sub length on that shot? Was this again without the f/5 reducer? Was this with your make-shift mirror lock or without? Is Meade still trying to reduce mirror deflection? Is the OTA you are using with any improvements Meade has already made to it?
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n2dpsky
member
Reged: 05/01/12
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Re: Jason Ware's LX800
[Re: n2dpsky]
#5566410 - 12/11/12 06:27 PM
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Awesome Rosette, Jason.
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germana1
sage
   
Reged: 05/14/09
Loc: New Jersey
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Re: Jason Ware's LX800
[Re: n2dpsky]
#5566416 - 12/11/12 06:33 PM
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I think that shot looks great, I couldn't even come close to getting anything like that stars look round impressive nice work. Pete
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Jared
Post Laureate
   
Reged: 10/11/05
Loc: Piedmont, California, U.S.
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Re: Jason Ware's LX800
[Re: galaxy_jason]
#5566427 - 12/11/12 06:44 PM
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Quote:
Accusations of falsifying data will get an emotional repsponse.
Last night was a little better seeing, not great, around 2" best focus. I also got a chance to try the latest firmware. This included some PEC updates and Starlock initialization updates.
Here is a 5.5 hour HA Rosette shot. The starlock tracking is essentially perfect. For the pixel peepers, you will see a very slight (about 1 pixel which is .77 arc seconds) diagonal elongation at the center of the frame. I believe this is the last bit of differential flexure. Not bad for a Cat.
Keep in mind this is an undprocessed image. Just combined then a slight stretch in PS. Many masterpieces you see on the net are deconvolved, dark overlay trailing reduced, etc.
http://galaxyphoto.com/tmp_800/rosett_5.5.jpg
That's actually pretty impressive. I would 't have expected so little trailing at 2,400mm focal length using a guide scope. Nice!
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korborh
professor emeritus
   
Reged: 01/29/11
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Re: Jason Ware's LX800
[Re: freestar8n]
#5566491 - 12/11/12 07:38 PM
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None of the images I have seen with lx800 and a large sct show any benefit of the greater aperture and I think better results would be achievable with a well-focused 130mm refractor - and it would be much easier to operate. Frank
And the latest posted image is no exception. Stars are round but bigger in size (arcsec) than what the optics allows. Stacking of flexure affected images can result in round stars but they will be large. To see flexure and image quality, un-processed individual raw subs would be best.
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