Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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A pretty decent night weather wise turned into a fantastic/horrible night mount wise. It may be me so that is why I am posting this.
To begin with, nothing could be easier than connecting the scope to The Sky6. EVERY mount should be this easy to interface with a computer. Bonus #1
GoTo's with a 1 STAR alignment were amazing. Synch on Sirius, GoTo M81 and BAM, right smack in the middle of the chip on my ST2K. Bonus #2
Than the horrors began. I'm pretty sure the polar scope is accurate and the bubble level looks to be calibrated spot on. I picked up a decent guide star, calibrated no problem and figured, "Lets see what this baby can do" Thats when the fun began. X errors enevr climbed above .6-.75 during a 10 minute exposure. The Y axis on the other hand was ALL over the freakin' place. It would run .2, .2, .35, .15, 2.25! back to .3 and repeat this cycle though not of a repetitive nature. 4 or 5 small corrections followed by 1 or 2 big corrections. I did not drift align as I thought I wouldn't have to with the TAK PS. It didn't matter what settings I tried or what I changed. If I turned Y corrections off the star would slide of the screen as if the PA was horrible ?? I performed the PA as well as the intial alignment both with the OTA on the West side of the mount, CW's on the East. I don't think I was chasing the seeing as I didn't see the same behaviour on the X axis which I thought I would see if the seeing was that bad. After 3 hours of pulling my hair out I packed it in and called it a night.
Any ideas would be greatly appreciated. I love sooo much about this beast but right now, it's a step below the CGE as far as autoguiding goes and a mountain below the MI-250.
Cs's
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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JerryWise
Postmaster
Reged: 12/26/03
Posts: 6850
Loc: Lexington, SC
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I had a similar experience with my new one and an STV. I calibrated the polar scope, refined the polar alignment and cut the autoguider off. You've seen my pictures. Seems the Autoguider can't believe what it's trying to drive.
Trust the force.......
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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Jerry,
I know what your saying but your also not shooting anything in Ha. I'm looking for 20-30 minute subs and even a Paramount can't do that unguided. It has to be my Polar scope becuase I cannot do 3 minutes unguided without trailing. I need to figure what is messed up. The bubble seems calibrated and I'm using Polarisfinder 1.4 and matching it up but it's a no go. Geuss I need to take the time to drift align.
Cs's
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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Dean
Post Laureate
Reged: 12/31/04
Posts: 4356
Loc: Bailey Co Elev 8780 feet
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Sorry to hear that Bobby.
Did you polar align before putting the scope and stuff on it? When I first got my NJP, I aligned it with nothing - no counterweights or anything - only to find the guiding was really bad. Come to find out the mount and/or tripod settled a good bit after loading it up which threw the alignment off.
Now that I think of it though, my GOTOs were off as well, so that makes me think its not PA (the GOTO accuracy depends on PA accuracy). You can check the bubble level accuracy by doing a drift align and then level the bubble and see where Polaris is in the reticle and see how that compares to where you expect it to be. Also, if you use the bubble and polar align first, the adjustments needed to drift align will show you what direction it is off and by how much (that's how I figured out my problem).
The steady drift with corrections turned off sounds like PA being off, but the guide errors getting progressively worse and then coming back sounds like backlash (although you could have been seeing both). How was the camera oriented - were the errors in RA or DEC? If they were in DEC, the PA could be causing the drift. If they were in RA then the drift may be from the clutch slipping and the correction oscillation could be from the clutch grapping or the balance being heavy to the west, causing the worm gear to constantly have to catch up to the drive gear.
It's also possible the drive wasn't running at sideral rate, although I think that's the default at startup.
Lastly - did you happen to be near the meridian? NJPs can get pretty squirrely near the mreidian, especially if the balance is east-heavy.
Here's a thread on the Yahoo Tak group about a similar problem - Gene Horr has some detailed directions for checking the gears.
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deanrowe.net/astro
Whats with that avatar?
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havane45
professor emeritus
Reged: 09/28/06
Posts: 626
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Quote:
The bubble seems calibrated ...
I thought the same about my CGE ; compare it with a very acurate tool and you may have the same (bad) surprise.
Anyway, if the on-board bubble is not faulty, you will know it.
Laurent
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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Quote:
Quote:
The bubble seems calibrated ...
I thought the same about my CGE ; compare it with a very acurate tool and you may have the same (bad) surprise.
Anyway, if the on-board bubble is not faulty, you will know it.
Laurent
Laurent,
Thanks for the reply. This is not the same bubble level though. The NJPm has a bubble level to let you know when the crosshairs of the polar scope are perpendicular to the horizon and have nothing to do with leveling the mount. My CGE's bubble level was surprisingly dead nuts on.
CS's
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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Dean,
I did perform the PA with the mount fully loaded and ready to image. The next clear night I plan on drfit aligning the mount as best I can to see if that was the issue.
The camera was oriented with all the connections pointing skyward. In other words, bottom of the camera up. I have always been confused as to the correct orientation of the camera when using a refractor. I also performed the PA with the OTA on the West side of the mount. I didn;t think it would/should make a difference.
I'm 99% sure the tracking was set to sidereal. I also tried correction speeds from 20% of tracking speed to 90% all to no avail. Agressiveness settings from 2 -10 also were of no help.
It's funny becuase the corrections in DEC were not progressive. They would run from 20's to 50's and than out of nowhere jump to 1.5 back to 20's etc than jump to stupid numbers like 2.36. Makes for some pretty ugly images. I also was not near the meridian at any time.
The one thing I did notice later on is that my FWHM were in the low 3's to mid 4's. I'm wondering if a bad PA coupled with bed seeing could have been cuasing these issues.
I read through the Yahoom posting and everything that I could check seems to be perfect. Imeasurable backlash, at least none that could be felt and the spurswere setup according to Art at TNR so I'm at a loss.
Thanks SO much for the help!
CS's
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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Rusty
Postmaster
Reged: 08/06/03
Posts: 16352
Loc: Brooker, FL
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Could it be the guiding was set to too much or too little aggressivness - or the interval was too long or short?
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N11GPS Fastar
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Two not-spoiled Golden Retrievers - Maggie and Casey
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Dan G
Pooh-Bah
Reged: 06/27/06
Posts: 1024
Loc: Minisink, NY, USA
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Bobby -
Last night our seeing stunk!! My EM-200 was bouncing like crazy - same FWHWs you observed. A couple questions. What did you have your Min Move times set to? I know the NJP differs from the 200 but do you have the Longitude value set correctly? This is easy to mess up on the 200 so thought I would ask. Is the scope tail heavy? Taks seem to like this much better than a balanced x axis. How long were your guide intervals?
Dan in NY
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TV 76, Vixen VC200L, TV NP-127is
EM-200, NJP
ST-2000xm and ST-402
Tranquility Base Observatory aka "The Shed" by non-tranquil members of the house
www.nyskies.com Still a work in progress!
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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My guiding intervals were anywhere from 5-10 seconds. My minimum move time was I believe.5 second ?? Not sure.
Longitude set were?
I had the scope perhaps just a bit tailm heavy in DEC and CW heavy (E) in RA.
Thanks Guys!
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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Dan G
Pooh-Bah
Reged: 06/27/06
Posts: 1024
Loc: Minisink, NY, USA
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Bobby -
Min Move .5 or .05? You might try in the .07 to .11 range for these guide intervals. Should reduce the hopping syndrome.
How do you set the Longitude for the NJP or is it accomplished through the PA scope?
Dan in NY
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TV 76, Vixen VC200L, TV NP-127is
EM-200, NJP
ST-2000xm and ST-402
Tranquility Base Observatory aka "The Shed" by non-tranquil members of the house
www.nyskies.com Still a work in progress!
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EricCCD
Pooh-Bah
Reged: 04/14/04
Posts: 1496
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Bobby,
If this mount is anything like the EM200, what is the hand control paddle speed switch set to: NS or HS (assuming the hand paddles are the same)?
NS = Normal Speed, HS = High Speed
For autoguiding, the hand paddle switch must be set to NS, otherwise corrections will be made at slew speeds. Not good.
You did mention that you calibrated for autoguiding fine, so you probably had your hand paddle set up right, but just in case...
I know that even experienced imagers get thrown for a loop the first autoguided imaging session with their first Takahashi mounts for this very reason.
I've had my EM200 for over three years now, but on occasion this still gets me.
HTH,
Eric
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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Quote:
Bobby -
Min Move .5 or .05? You might try in the .07 to .11 range for these guide intervals. Should reduce the hopping syndrome.
How do you set the Longitude for the NJP or is it accomplished through the PA scope?
Dan in NY
Dan,
.05 as my minimum move time and 1.0 as my maximum. .250 as my backlash compensation in both Axis. Agg was set anywhere between 2 and 10. Didn't seem to make a difference.
as far as longitude I set that up using my GPS unit. I than plugged that into "Polarisfinder 1.4" I was a bit concerned as it was a bit hazy when I setup the mount and wasn't quite sure if it was actually Polaris I was using. The PS in the NJP doesn't offer the magnification some of the others I have owned did. Could I have been that far off. I am at 40.53 according to my GPs unit. When I look at the mount, the latitude scale shows roughly 43-44 degrees. Normally I don't trust these scales so I wasn't really concerned. If I dropped it down to 35 I could not see a star bright enough that I thought it would be polaris. This is my main reason for redoing it.
Thanks bud!
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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Quote:
Bobby,
If this mount is anything like the EM200, what is the hand control paddle speed switch set to: NS or HS (assuming the hand paddles are the same)?
NS = Normal Speed, HS = High Speed
For autoguiding, the hand paddle switch must be set to NS, otherwise corrections will be made at slew speeds. Not good.
You did mention that you calibrated for autoguiding fine, so you probably had your hand paddle set up right, but just in case...
I know that even experienced imagers get thrown for a loop the first autoguided imaging session with their first Takahashi mounts for this very reason.
I've had my EM200 for over three years now, but on occasion this still gets me.
HTH,
Eric
Eric,
Lol Lol did that 3 times while calibrating the stupid mount. learned my lesson in a hurry about that stupid little switch 
I am at a loss other than a bad polar alignment or REAL bad seeing.
I also need to Dl the manual as I have no idea what any of the other buttons on the HC are used for.
Thanks!
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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EricCCD
Pooh-Bah
Reged: 04/14/04
Posts: 1496
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Quote:
I also need to Dl the manual as I have no idea what any of the other buttons on the HC are used for.
Are those buttons marked S1/S2 or something like that? If so, they're just to adjust the correction speeds, which you can do with TheSky.
Quote:
Lol Lol did that 3 times while calibrating the stupid mount. learned my lesson in a hurry about that stupid little switch
Ok, we got that base covered
At this point, I'm at a loss myself other than what you're going to try (drift alignment or otherwise good polar alignment).
One thing for you to try (though this is another learning curve): PoleAlignMax. As wonderful as my EM200's PA scope is, I've been in situations where I can't see Polaris. PoleAlignMax gets me polar aligned in a half hour at worst (And that's if I fat finger my adjustments!). The price is right, too (freeware!).
HTH,
Eric
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Dan G
Pooh-Bah
Reged: 06/27/06
Posts: 1024
Loc: Minisink, NY, USA
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Bobby -
Why did you set the backlash comp? Have you found an issue with this occurring? I must agree with Jerry - trust the force. Coming from the CGE as you did I had that every little tweak mentality. And initially the mount was jumping all over the place.
I have found the less I do the better. Backlash set to 0, Min move at .08, 4 sec guide intervals, Aggressiveness as low as I can go = round stars. BTW - the seeing really sucked the other night so this just exacerbated every issue you had  And that stupid little NS/HS switch has caught me more times than I care to count.
Dan in NY
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TV 76, Vixen VC200L, TV NP-127is
EM-200, NJP
ST-2000xm and ST-402
Tranquility Base Observatory aka "The Shed" by non-tranquil members of the house
www.nyskies.com Still a work in progress!
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JerryWise
Postmaster
Reged: 12/26/03
Posts: 6850
Loc: Lexington, SC
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Quote:
......... And that stupid little NS/HS switch has caught me more times than I care to count.
Dan in NY
I call it the "Start Over" switch. Back to aligning and syncing Sky 6 after forgetting the little booger.
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Jerry
LX200ACF 14", Tak FS 152 & TOA 150
AP-1200 & Mach1
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Joe Cipriano
Entropy Personified
Reged: 09/03/05
Posts: 3830
Loc: Uh... anyone have a GPS?
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Quote:
I call it the "Start Over" switch...
Yup - add me to the list. Couldn't figure out why the 208 was swinging the NJP's Dec 45 degrees to calibrate... 
I have not had a chance (or the weather) to try the NJP out for AP; however, I got good AG test results (0 to 1 pixel corrections over about 30 minutes) with 4-5 sec intervals. 1 sec intervals (the ideal for my CGE) had the NJP bouncing all over the place...
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In the Land of Eternal Light Pollution & Great Pizza (Chicago)
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Strgazr27
Scope Junkie
Reged: 10/04/04
Posts: 5970
Loc: StonyHill Observatory
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Quote:
Bobby -
Why did you set the backlash comp? Have you found an issue with this occurring? I must agree with Jerry - trust the force. Coming from the CGE as you did I had that every little tweak mentality. And initially the mount was jumping all over the place.
I have found the less I do the better. Backlash set to 0, Min move at .08, 4 sec guide intervals, Aggressiveness as low as I can go = round stars. BTW - the seeing really sucked the other night so this just exacerbated every issue you had And that stupid little NS/HS switch has caught me more times than I care to count.
Dan in NY
Dan,
I geuss like you I thought I had to tweak the hell out of it to get it to work. The next good night I'm going to start from scratch and see what happens. I'm going to bring the mount to work with me this week if I go back and hang a plumb bob in the storage building. This should allow me to calibrate the bubble level. I'll than bring it home and see what happens.
I'm not use to NOT having to tweak the hell out of my mount to get it to work. Even the MI needed a bit of finessing to get it to AG nicely.
Thanks for the help!
CS's
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Bobby
StonyHill Observatory
Atlas w EQMOD
Vixen R200SS
Orion ED-80
AT-111
AT66-ED
QHY-8
SSAG
YAHOO TMB 130SS Group
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EricCCD
Pooh-Bah
Reged: 04/14/04
Posts: 1496
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That's what I forgot to mention as well, Bobby: the Backlash Comp setting. I made a mental note when I saw it but forgot all about it until someone else brought it up.
The best approach to Tak equipment: start from zero, and tweak only if necessary. Repeat as needed.
I've always wondered about whether I needed to measure and/or set Backlash Comp with my EM200. At this point I haven't bothered, and my stars are round, so I'm happy
Eric
PS: Happy Birthday! You share a birthday with Elizabeth Taylor and Joanne Woodward, among others 
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