Jump to content


Photo

Imaging With A Titan Mount

astrophotography
  • Please log in to reply
39 replies to this topic

#1 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 04 August 2014 - 11:01 AM

Hi,

I have purchased a Titan mount with Gemini 1 primarily to image.  Unfortunately since buying the mount I have been unable to use it to image as I cannot calibrate the mount in Maxim dl or any other software. Instead of getting the L shape calibration I get something akin to a W.

I have sent the mount to Ovison for a full service and when I got the mount back I still add exactly the same problem. Ovision have used the mount with a 12” Celestron and the mount performed perfectly for them.  The computer links to the mounts as I can move it using Maxim or Starry Night.

I have changed all the cables even the computer but the error remains. The error is always exactly the same even when I point the telescope in different parts of the sky. I also used a different camera. I use an ST4 cable to see if that would make a difference but I still get exactly the same pattern.

I have attached an image of the error and I hope that someone will recognise the problem. I honestly don’t know what to do anymore and I can’t even sell the mount as there is this problem.

The image was taken with a QHY6 mono and the mount was moved 15 seconds of arc during a 7 seconds exposure for all 4 frames.

Please help as I am really depress wit this. I bought this mount for my retirement and so far I am utterly frustrated with it.

Thank you for your help.

Vince

 

Attached Files



#2 Hilmi

Hilmi

    Soyuz

  • *****
  • Posts: 3819
  • Joined: 07 Mar 2010
  • Loc: Muscat, Sultanate of Oman

Posted 04 August 2014 - 11:11 AM

Looks to be a combination of backlash and being west heavy.

 

Since the mount has been professionally inspected and came out fine. I would say the first thing you need to look at is your balance.

 

Also, you can download PEMPro demo and try the backlash exerciser to see how much backlash you have.



#3 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 04 August 2014 - 05:17 PM

Thank you for your answer.

I have checked and adjusted the balance and the backlash but nothing seem to affect what the picture is showing. It doesn't matter what the backlash setting is the jumps are always there.

If I move the scope using the hand pad I get straight line.

Thank you for your help.

Vince



#4 David Rosenthal

David Rosenthal

    Imager Extraordinaire

  • *****
  • Posts: 3151
  • Joined: 23 Jun 2006
  • Loc: NJ

Posted 05 August 2014 - 06:19 AM

What software are you using for guiding?

Are you pulsefuiding through ASCOM or through ST-4 relays?



#5 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 05 August 2014 - 08:36 AM

HI,

The software I use for guiding is Maxim DL5.

I have tried both ASCOM and ST4 with exactly the same result.

Thank you for your help.

Vince



#6 kbastro

kbastro

    Viking 1

  • *****
  • Posts: 955
  • Joined: 20 Apr 2008
  • Loc: Running from Clouds

Posted 05 August 2014 - 09:27 AM

Hello Vince;

 I see the image you put up showing calibration error,,

 

Have you checked your Teflon disc? making sure it is oil/grease free?

 

Have you checked your bearings?

 

Are the end caps on the worm block/worm housing snug and tight? feeling, seeing or hearing no movement when you lock clutches and grab counterweight

shaft and pull back and forth??  (this is hard to detect as the movements will be miniscule) best way to do this is put your

finger on the round worm block's end cap and again grab the counterweight shaft and move it east & west with a scope load and clutches tight.. 

Do the same for the Dec but this time grab your scope and check the Dec's worm block and again use your finger to feel any movement or tapping against the cap

 

double check your autoguider cable, ports and turn cable around

 

Balance is critical,, Titans are free floating and have no resistance so when the clutch is loose

 everything moves freely,,, which leads to my next question,,,,

When you tighten your clutches RA and dec circle,,, how hard is it to push or pull

your scope??

 

Kevin



#7 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 06 August 2014 - 07:30 AM

Hi Kevin,

Thank you for getting back to me.

I have checked the Teflon disc and they are both in pristine condition. No grease nothing untoward.

The Mount has been serviced by Ovision 2 months ago and everything seem perfect to me. Ovision have had a 14" Celestron on it for testing and the mount performed superbly. I went to collect it myself in order to avoid any damage in transit.

I have changed all the cables but to no avail.

If I move the mount using the handpad I get perfect straight lines on all 4 axes.

The clutches are nice and tight too.

It is impossible to image with the mount. I have tried changing the various parameters but it doesn't seem to do anything to the calibration issue. I always get the same W pattern.

thank you fro your help.

Vince

 

 

Attached Files



#8 David Ault

David Ault

    Viking 1

  • -----
  • Posts: 539
  • Joined: 25 Sep 2010
  • Loc: Georgetown, TX

Posted 06 August 2014 - 09:06 AM

I'm grasping at straws here, but why don't you try PHDGuiding or Metaguide (if you have an appropriate guide camera) and see if they do any better.  That will at least tell you if its a software/driver issue.

 

Regards,

David



#9 David Rosenthal

David Rosenthal

    Imager Extraordinaire

  • *****
  • Posts: 3151
  • Joined: 23 Jun 2006
  • Loc: NJ

Posted 06 August 2014 - 09:14 AM

I have been guiding with MaximDL for years now and that calibration graph tells me you have a decent amount of backlash and/or improper balance present in both Axis.  Are you ofsetting the RA balance?



#10 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 06 August 2014 - 02:12 PM

HI,

I have used PHD with the same result.

The mount has been service by Ovision the French importer who was able to image with a 14" celestron without any problem.

I went to collect the mount myself to avoid the transporter damaging the mount in transit and after checking with the importer he confirmed that everything on the mount in perfect. He also supplied an error graph which shows an error rate of 5" from peak to peak.

I double checked everything myself and everything seem to be spot on.

When I move the mount using the Gemini hand controller or the Gemini driver I get perfect straight lines the problem occur only when I try to calibrate Maxim for autoguiding.

Without any autoguiding I can get a 2 minutes exposure without trailing.

Thank you for your help.

Vince



#11 blueman

blueman

    Photon Catcher

  • *****
  • Posts: 5487
  • Joined: 20 Jul 2007
  • Loc: California

Posted 06 August 2014 - 05:47 PM

Have you  asked about this on the Maxim DL forum? Perhaps you should put in a ticket with Maxim DL too.

Without knowing exactly how you have you guiding set in Maxim, it is hard to be sure why you are having an issue. But if Ovision was able to guide perfectly, then I suspect it is your setup or your guiding hardware.

Blueman



#12 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 07 August 2014 - 12:45 AM

Hi,

Thank you for that. You must be right as I seem to have tried everything else.

thank you

Vince



#13 Madratter

Madratter

    Fly Me to the Moon

  • *****
  • Posts: 7150
  • Joined: 14 Jan 2013

Posted 07 August 2014 - 09:10 AM

Please don't take this the wrong way as I don't know what level you are at. But are you sure your polar alignment is good? Bad polar alignment will cause drift in both declination and RA, and can lead to this sort of thing.

 

EDIT: Actually it won't given the shape of your test images. It would be a more smooth transition. Can't find a delete button on this version of CN.


Edited by Madratter, 07 August 2014 - 09:12 AM.


#14 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 08 August 2014 - 01:12 AM

I think this mount is a heap of ........

I am so sorry I ever bought it and now it will be a museum piece I shall never be able to use.

I bought after I was told that I had a serious heath issue so I was thinking that life was to short and that I should treat myself before it is too late. Now I will just have to think of what could have been.

Thank you all for your help.

Vince



#15 fetoma

fetoma

    Vanguard

  • *****
  • Posts: 2432
  • Joined: 26 Sep 2006
  • Loc: Southern NJ

Posted 08 August 2014 - 11:21 AM

Vince,

 

Stop messing with it and call Scott Losmandy.

 

Hollywood General Machining, Inc.
1033 N. Sycamore Avenue
Los Angeles, California   90038
323-462-2855       FAX: 323-462-2682



#16 blueman

blueman

    Photon Catcher

  • *****
  • Posts: 5487
  • Joined: 20 Jul 2007
  • Loc: California

Posted 08 August 2014 - 01:04 PM

I have a friend that images with a Titan, it works very well, even with a C-14. You have an issue that is probably not the mount. You need to get some help with it from Losmandy but it may not have anything to do with the mount at all and they will not have a clue either. As I stated earlier, if Ovision said it worked fine for them, then it is something about your setup.

Blueman



#17 blueman

blueman

    Photon Catcher

  • *****
  • Posts: 5487
  • Joined: 20 Jul 2007
  • Loc: California

Posted 08 August 2014 - 04:00 PM

To give you any help at all we will have to know more about how you have the guiding setup in Maxim, what type of guiding you are doing (OAG, Guide Scope) and exactly how you are balancing or setting the backlash.

Blueman



#18 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 10 August 2014 - 04:19 AM

HI,

Thank you for getting back.

The setup in Maxim is the default setting without any backlash or anti-stiction. When I dial some backlash I still get exactly the same error. It is almost as if the backlash did not exist.

When I use the serial cable to guide I set the guider output to "telescope".

I have also tried to guide using an ST4 cable and again set the guider output to the "guider relay" and I also tried "main relay" but I always get the same issue. 

To connect the mount to the controller I use a usb to serial converter and a serial cable from the converter to the controller. To ensure that it wasn't a cable issue I changed both cable and I got the same result.

I am using a QHY6 to guide with a 80mm guidescope sitting on the top of a 5" refractor.

To image I am using a Trius 814 mono.

I also changed the guide camera to ensure it wasn't the camera but I still got the same result.

The balancing is East heavy otherwise the balance is excellent.

I have been imaging for some 10 years now and I never encountered this kind of problem and after having made so many changes I always end up with the same result.

Thank you for your help.

Vince



#19 liors

liors

    Explorer 1

  • *****
  • Posts: 99
  • Joined: 06 Aug 2011
  • Loc: Israel

Posted 10 August 2014 - 06:48 AM

Hello Vince,

 

To me it looks like a guiding error, I`m using PHD2 so I don`t have experience with Maxim DL.

I read all the threads above and it seems you almost tried everything.

I can only contribute to this discussion is to ask you if you ever calculate the Are Second Per Pixel for both guide scope and imaging scope? 

Have you checked/calculate minimum motion?

Are you using Ascom Gemini 1? Or you enter the IP port of Gemini using Ethernet cable?

 

Lior



#20 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 10 August 2014 - 08:06 AM

Hi,

I would agree with you that it is a guiding error but I cannot put my finger on what could be creating the issue.

I have tried guiding with Phd and I get the same problem as with Maxim where the guiding is atrocious.

Unfortunately all I know from Ovision is that the tracking error is less than 8" and that Ovision as able to guide happily with a 14" celestron.

Yes I am using Ascom and Gemini 1.

Vince



#21 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27940
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 10 August 2014 - 10:06 AM

I've read through this and if I missed it, I apologize.  Have you tried guiding with PHD2 and checked the graph to see if the glitch happens at exactly the same moment or if it's random?  If it is consistent, I'd go with a mechanical problem that is directly tied to the motion.  If it's random, then it becomes a real nightmare.  In PHD, I'd first try guiding without Dec correction and watch your graph.  When RA corrections are made, the mount slows down or speeds up, in Dec it changes directions.  That change in direction may be where you're getting that bad reading.

 

So...see if you can find whether it's a repeatable event or if it's random.  At least it's a start.

 

David



#22 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 10 August 2014 - 10:17 AM

The glitch happen at exactly the same time over and over again.

Vince



#23 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 07 September 2014 - 05:08 AM

Hi,

I may have found the problem but as it is cloudy I cannot check it out and maybe someone has the experience and advise me.

As the observatory is 50 meters from the house I use an extension lead to power everything in the observatory. A friend suggested that the cable is not man enough for the job and that the mount could be lacking in power.

I know a bigger cable is not that expensive but before I go and get one I wondered what you thought of this idea.

Thank you for your help.

Vince



#24 GeorgeInDallas

GeorgeInDallas

    Ranger 4

  • -----
  • Posts: 309
  • Joined: 15 Apr 2012
  • Loc: Dallas, Texas USA

Posted 07 September 2014 - 11:01 AM

Vince,

 

I really hate to see someone have so much difficulty, particularly under the circumstances. Where are you located? Is there some way that you can get someone, with imaging experience, to come to your location and put a second set of eyes on your setup? Two heads are usually better than one. Maybe when you bounce the details off of someone the answer will become clear.

 

Good Luck,

George



#25 hungerford

hungerford

    Messenger

  • -----
  • Posts: 436
  • Joined: 23 Aug 2008

Posted 07 September 2014 - 12:57 PM

Hi George,

I live in France in the middle of nowhere and it is impossible to get help anywhere in the area. Ovision is based in the south at some 7/8 hours drive and they cannot help as I am too far.

Thank you for your support.

Vince







Also tagged with one or more of these keywords: astrophotography



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics