Image of the day

From the
ATWB Customer Gallery

NGC 2170

My Account

New to Astromart?

Register an account...

Need Help?

Posts Made By: Tom McDonagh

January 26, 2003 02:26 AM Forum: Equipment Talk

Freeing stuck FR/FF from NGF-S focuser

Posted By Tom McDonagh

Hello:

I have been using a JMI NGF-S Focuser in conjunction the a Meade F/6.3 Focal reducer/Field flattener. The setup has worked well. Now I wish to unscrew the FR/FF from the focuser. I am having a hard time as they now seem to be welded together(figuritively speaking). No amount of reasonable pressure or change in temperatue has worked. Any suggestions?

Thanks in advance!

Tom

June 4, 2003 02:42 PM Forum: CCD Imaging and Processing/Solar System

Voltage regulator VR4? for Cookbook 245

Posted By Tom McDonagh

Hi Folks:

Can someone supply me with the name of the voltage regulator positioned at VR4 on the circuit card for the cookbook ccd camera? I left my book at home and need to get a replacement.

Thanks,

Tom

June 4, 2003 02:43 PM Forum: Telescope Making

Cookbook 245 VR4?

Posted By Tom McDonagh

Hi Folks:

Can someone supply me with the name of the voltage regulator positioned at VR4 on the circuit card for the cookbook ccd camera? I left my book at home and need to get a replacement.

Thanks,

Tom

June 15, 2003 07:06 PM Forum: Equipment Talk

GP-DX polar scope calibration

Posted By Tom McDonagh

Hi Folks,
I'm looking for help in calibrating my new/used vixen GP-DX. I'm a bit confused regarding the directions related to the calibration of the RA/hour/date calibration with the position of polaris. On page 14 of the gp manual, see: http://home.online.no/~arnholm/astro/gpmanual/gpmanu14p.jpg for details.
The problem I have encountered is that the silver hour graduation ring freely rotates and I would expect it to rotate with RA rotation. That does not appear to be the case. Can someone enlighten me?
Thanks,

Tom

June 26, 2003 05:19 AM Forum: Meade

dead 8" f/10 LX200, suggestions?

Posted By Tom McDonagh

Transcript to owner:

Hi Carl:

Spent a few hours on your scope last night with no success. I am still seeing controller lockup upon initialization at the "meade" prompt. Checked everything I could check without tearing it all apart. Here's what I did:

Power supply voltage reads 21.1 volts with no load. Should be ~ 18 volts? Could it be the problem? Did you say you tried it with the 12 to 18 volt converter? You may want to asked mapugger's about this.

Checked the DEC and handpaddle cable for continuity. They seemed fine to me. So the cables are fine but that does not mean the sockets are. Can't pursue that any longer.

Pulled the base off. Checked the operation of the RA motor. Seems to turn fine upon startup. Cleaned off the worm shaft of heavy grease buildup where the hall sensor magnet is to no effect. Shorted pin7 of the RA cable to motherboard with no effect.

Checked the battery on the daughter board. Read out 2.92 volts. Shoud be fine but you may want to check with other meadeites.

Performed startup with keypad disconnected. The scope went through the same operation without it

If I had to make a guess, I would say it was one or more of the following things:
Bad cable connectors
Motherboard or keypad daughterboard or entire keypad
DEC motor and or electronincs
RA motor and/or electronics (bad hall sensor, bad indexing ring/LEDS/detectors)

I also noted that the two heatsinked IC's that generally attached to the baseplate via allen bolts did not appear to be so. That might cause failure or erratic electronic behavior due to overheating. I never opened the baseplate before and noted the allen bolts were not flush with the baseplate when I received it from you. It must have been from when you first removed the baseplate as they were always flush to the plate in the past.

I would contact a serious repair service, be that Meade or other group and consider a motherboard/DEC/RA motor replacement option. Another option would be to keep your eyes out for a used fork/electronics setup on astromart. Some people pull the OTA from the setup, then put the rest up for sale. Might be cheaper than returning the scope to Meade. Last option would be to pull the OTA yourself and find a decent GEM mount to put it on. The 8" f/10 LX200 OTA is on the high end for weight with the Vixen GP type mount which is affordable and a great astrophoto performer. Proper balanceing would be key.

Let me know what you think. Sorry I could not be more helpful!!!!!

Best regards,

Tom

February 3, 2004 02:17 PM Forum: Equipment Talk

Servo controllers

Posted By Tom McDonagh

Why are servo controllers so much more expensive than their stepper counterparts?

Thanks,

Tom

March 23, 2005 09:29 PM Forum: Mounts

Parallax 125 Mount

Posted By Tom McDonagh

Anyone out there with any experience with this mount? I just purchased a used one over Astromart. I measure the PE to be ~ +/- 10 arc secs the other night. It seems quite beefy!
Looking to Bartleize it with his new servo system. Any thoughts?

Tom

August 31, 2006 03:59 AM Forum: Telescope Making

Vixen GP-DX motor mount design

Posted By Tom McDonagh

Hi Folks,

I'm looking to mount up some steppers or srvos to my GP-DX. Does anyone hae a motor mount design for the RA and Dec axis available for review?

Thanks,

Tom

April 12, 2010 08:32 AM Forum: CCD Imaging and Processing/Deep Sky

Looking for ideas on a simple mount for drift scan

Posted By Tom McDonagh

Hi Folks,

Looking for ideas on a mount I can build for Drift scanning with my ST-9. I would like to build it with the capability to adjust the angle so that the star point can be adjusted so that migrates down the chip pixel column.

Any thoughts? I have basic woodworking skills.

Thanks,

Tom

April 12, 2010 08:46 AM Forum: Equipment Talk

Looking for ideas on a simple mount for drift scan

Posted By Tom McDonagh

Hi Folks,

Looking for ideas on a mount I can build for drift scanning with my ST-9. I would like to build it with the capability to adjust the angle so that the star point can be adjusted so that migrates down the chip pixel column.

Any thoughts? I have basic woodworking skills.

Thanks,

Tom