Periodic Error Correction - Revision history

Jgoodma2: /* Periodic Error Correction */

2010-06-21T02:59:36Z

Periodic Error Correction

← Older revision		Revision as of 02:59, 21 June 2010
Line 22:		Line 22:
	Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).		Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).

	5. Open Notepad, and open the file you just saved. ~~copy~~ the entire thing, and switch back to the The Sky PEC window (Figure 1). Here, click the ~~past~~ button. Your curve should appear in the table window. Click upload to save this curve. To apply ~~teh~~ correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.		5. Open Notepad, and open the file you just saved. Copy the entire thing, and switch back to the The Sky PEC window (Figure 1). Here, click the paste button. Your curve should appear in the table window. Click upload to save this curve. To apply the correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.

	Status(06/03/2010): With correction applied, PEMpro measures a much reduced but still extant periodic error, of about an arc second, more extreme in one half of the period than the other. Guiding in X shows a similar, still present periodic behavior, but it is less extreme and has many fewer jumps.		Status(06/03/2010): With correction applied, PEMpro measures a much reduced but still extant periodic error, of about an arc second, more extreme in one half of the period than the other. Guiding in X shows a similar, still present periodic behavior, but it is less extreme and has many fewer jumps.

Jgoodma2: /* Periodic Error Correction */

2010-06-08T19:51:05Z

Periodic Error Correction

← Older revision		Revision as of 19:51, 8 June 2010
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	[[File:uncorData.png]]		[[File:uncorData.png]]

	Figure 2: Raw data with correction off from 06-01-2010 in the analyze tab of the main menu, and the PEC curve creation window fitting a curve to the data.		Figure 2: Raw data (with correction turned off) from 06-01-2010 in the analyze tab of the main menu, and the PEC curve creation window fitting a curve to the data.

	4. Close the Create PE curve window. In the main PEMpro window, switch to the Refine tab and and load the curve data (not the original data) you just saved by clicking the 'Curve 1' button. Assuming the curve was not earlier inverted, click the Invert button next to where you loaded Curve 1. We determined (06/02/2010) that when we save a file here, and copy the data into the actual Periodic Error Correction window in The Sky (which does the actual correcting and actively follows the phase of the worm gear) there is a phase offset of 600 units (~66 seconds). On top of that, the zero phase point of the worm gear, as read from the The Sky window, corresponds to about the 15s phase point in PEMpro, requiring and additional 139 unit offset (the math: the worm gear cycle is divided into 1250 units, and has a period of 134.63 seconds. This corresponds to 9.3 units/second). ~~Original~~ offset was found by putting a spike in the The Sky correction curve, recording this spike in PEMpro, and then shifting the recorded curve fit and pasting it back into the sky until the ~~spike's~~ matched up. The 15s phase offset we ~~notcied~~ while ~~Acquiring~~ data, by seeing that the The Sky phase mark line ~~passsed~~ its zero point when in the PEMpro window the Current Worm Phase was at 15s. So the total offset we ~~decide don~~ is 740 units. So: using the Shift Curve section at the bottom of the window, shift the curve (make sure the pull down is on the correct curve) to an offset of +740 units (to the right. The maximum shift for each step is 50 units, so this will take some clicks. the recorder of the shift may wrap around to negative values, so you may have to keep track of how far you shifted to the right.) The curve fit from our 06/01/2010 data is shown in the Refine tab in Figure 3, along with its shifted and inverted version. Save ~~teh~~ curve from ~~teh~~ Save section , again selecting the right curve from the pull down. In the save window, select Paramount PEC files (*.txt) from the Save as type pull down.		4. Close the Create PE curve window. In the main PEMpro window, switch to the Refine tab and and load the curve data (not the original data) you just saved by clicking the 'Curve 1' button. Assuming the curve was not earlier inverted, click the Invert button next to where you loaded Curve 1 (trial and error taught us that we need to invert the curve). We determined (06/02/2010) that when we save a file here, and copy the data into the actual Periodic Error Correction window in The Sky (which does the actual correcting and actively follows the phase of the worm gear) there is a phase offset of 600 units (~66 seconds). On top of that, the zero phase point of the worm gear, as read from the The Sky window, corresponds to about the 15s phase point in PEMpro, requiring and additional 139 unit offset (the math: the worm gear cycle is divided into 1250 units, and has a period of 134.63 seconds. This corresponds to 9.3 units/second). The original offset was found by putting a spike in the The Sky correction curve, recording this spike in PEMpro, and then shifting the recorded curve fit and pasting it back into the sky until the spikes matched up. The 15s phase offset we noticed while acquiring data, by seeing that the The Sky phase mark line passed its zero point when in the PEMpro window the Current Worm Phase was at 15s (you can verify this). So the total offset we decided on is 740 units. So: using the Shift Curve section at the bottom of the window, shift the curve (make sure the pull down is on the correct curve) to an offset of +740 units (to the right. The maximum shift for each step is 50 units, so this will take some clicks. the recorder of the shift may wrap around to negative values, so you may have to keep track of how far you shifted to the right yourself.) The curve fit from our 06/01/2010 data is shown in the Refine tab in Figure 3, along with its shifted and inverted version. Save the curve from the Save section , again selecting the right curve from the pull down. In the save window, select 'Paramount PEC files (*.txt)' from the 'Save as type' pull down.

	[[File:refine.png]]		[[File:refine.png]]

Jgoodma2: /* Periodic Error Correction */

2010-06-08T19:44:04Z

Periodic Error Correction

← Older revision		Revision as of 19:44, 8 June 2010
Line 10:		Line 10:
	2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but not saturated. Press Start to begin acquisition. Once the image is exposed, check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods, until you have a good looking periodic curve.		2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but not saturated. Press Start to begin acquisition. Once the image is exposed, check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods, until you have a good looking periodic curve.

	3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper left pull down menu. The RMS error in the upper right may be of interest. This window, along with the analyze data tab in the main window displaying the raw data collected (with the correction turned off) on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since ~~as we will see~~ we can do it in the Refine window.		3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper left pull down menu. The RMS error in the upper right may be of interest. This window, along with the analyze data tab in the main window displaying the raw data collected (with the correction turned off) on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since we can do it later in the Refine window.

	[[File:uncorData.png]]		[[File:uncorData.png]]

Jgoodma2: /* Periodic Error Correction */

2010-06-08T18:54:43Z

Periodic Error Correction

← Older revision		Revision as of 18:54, 8 June 2010
Line 10:		Line 10:
	2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but not saturated. Press Start to begin acquisition. Once the image is exposed, check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods, until you have a good looking periodic curve.		2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but not saturated. Press Start to begin acquisition. Once the image is exposed, check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods, until you have a good looking periodic curve.

	3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper ~~right~~ pull down menu. The RMS error in the upper ~~left window~~ may be on interest. This window, along with the analyze data tab in the main window displaying the raw data collected with the correction off on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since as we will see we can do it in the Refine window.		3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper left pull down menu. The RMS error in the upper right may be of interest. This window, along with the analyze data tab in the main window displaying the raw data collected (with the correction turned off) on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since as we will see we can do it in the Refine window.

	[[File:uncorData.png]]		[[File:uncorData.png]]

Jgoodma2: /* Periodic Error Correction */

2010-06-08T16:36:24Z

Periodic Error Correction

← Older revision		Revision as of 16:36, 8 June 2010
Line 23:		Line 23:

	5. Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window (Figure 1). Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. To apply teh correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.		5. Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window (Figure 1). Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. To apply teh correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.

			Status(06/03/2010): With correction applied, PEMpro measures a much reduced but still extant periodic error, of about an arc second, more extreme in one half of the period than the other. Guiding in X shows a similar, still present periodic behavior, but it is less extreme and has many fewer jumps.

Jgoodma2: /* Periodic Error Correction */

2010-06-04T19:41:59Z

Periodic Error Correction

← Older revision		Revision as of 19:41, 4 June 2010
Line 1:		Line 1:
	=='''Periodic Error Correction'''==		=='''Periodic Error Correction'''==

	1. Turn off PEC in The ~~SKy~~->Telescope->Options->More Settings by unchecking the "Apply PEC correction" box.		1. Turn off PEC in The Sky->Telescope->Options->More Settings by unchecking the "Apply PEC correction" box.

	[[File:unchecPEC.png]]		[[File:unchecPEC.png]]
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	2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but no saturated. Press Start to begin acquisition. Once ~~Image~~ is exposed. check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods.		2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but not saturated. Press Start to begin acquisition. Once the image is exposed, check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods, until you have a good looking periodic curve.

	3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper right pull down menu. The RMS error in the upper left window may be on interest. This window, along with the analyze data tab in the main window displaying the raw data collected with the correction off on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since as we will see we can do it in the Refine window.		3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper right pull down menu. The RMS error in the upper left window may be on interest. This window, along with the analyze data tab in the main window displaying the raw data collected with the correction off on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since as we will see we can do it in the Refine window.

Jgoodma2: /* Periodic Error Correction */

2010-06-04T19:31:24Z

Periodic Error Correction

← Older revision		Revision as of 19:31, 4 June 2010
Line 1:		Line 1:
	=='''Periodic Error Correction'''==		=='''Periodic Error Correction'''==

	~~'''Opening the Dome'''~~

	1. Turn off PEC in The SKy->Telescope->Options->More Settings by unchecking the "Apply PEC correction" box.		1. Turn off PEC in The SKy->Telescope->Options->More Settings by unchecking the "Apply PEC correction" box.

Jgoodma2 at 19:28, 3 June 2010

2010-06-03T19:28:45Z

← Older revision		Revision as of 19:28, 3 June 2010
Line 24:		Line 24:
	Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).		Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).

	5. Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window. Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. To apply teh correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.		5. Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window (Figure 1). Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. To apply teh correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.

Jgoodma2 at 19:27, 3 June 2010

2010-06-03T19:27:40Z

← Older revision		Revision as of 19:27, 3 June 2010
Line 24:		Line 24:
	Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).		Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).

	Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window. Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. In the ~~same window~~, ~~switch to~~		5. Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window. Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. To apply teh correction, disconnect PEMpro and Maxim DL from the camera, and back in the The Sky window switch to the "MKS 4000 options" tab, and in the reboot section click Normal. Click OK. The telescope should slew to home; you can send it yourself to make sure. Reopen the Telescope->options->more settings window, and go the PEC tab; click the Apply PEC correction box. The Preiodic error should now be correct! You can check this be Acquiring data in PEMpro, which should look much more flat, or by guiding and looking for periodic shifting.
	~~'''Powering up the Telescope'''~~

	~~5. Remove the cover for the large mirror.~~

	~~6. Turn ON the power on the black uninterrupted power supply (UPS) at~~ the ~~base of the telescope.~~ The ~~green power light will flash for a few seconds; wait until it glows steady green before proceeding.~~

	~~7. Turn ON the power for the telescope on the black box in the base. Listen for 2 beeps.~~



	~~'''Software Setup and Connections'''~~

	~~If not already on, start up the PC that operates the telescope.~~

	~~Log in~~ to the ~~PC as user~~ "~~telescope~~".

	~~13. Open TheSky6.~~

	~~14. Establish link to telescope by clicking green telescope icon~~ in the ~~top shortcuts menu~~

	~~15. Allow telescope to home if it wasn't done manually with the joystick. Listen for 3 beeps.~~

	16. ~~Open ddwcp.~~

	17. ~~Wait until program connects with the dome then check "Slave to Telescope."~~ ~~(Don't do this if you don't want the dome to move with the~~ telescope~~, i.e. if you want to take dome flats.)~~

	~~18. Open MaximDL Pro 5.~~

	~~19. Click "Toggle Camera Control" (Ctrl + W) in the top shortcuts menu.~~

	~~20. Camera 1~~ should ~~read "Apogee U16M".~~

	~~21. Select Camera 2 from Setup Camera, or "No Camera" if there isn't one connected.~~

	~~22. Click "Connect."~~

	~~23. Directly below "Connect", turn on Coolers. Set cooler set point with the Cooler button specific~~ to ~~each camera.~~

	~~24. Click "Toggle Observatory Control" (Ctrl + T).~~

	~~25. In the Setup Tab, check that under Telescope~~ it ~~reads "TheSky-controlled telescope" and that Focuser 1 reads "RCOS TCC".~~

	~~26. Click "Connect All".~~

	~~27. The telescope can be controlled under Observatory-Telescope (nudging or setting coordinates), set~~ to ~~specific objects through Observatory-Catalog, or moved through TheSky~~. ~~Manual control of~~ the ~~telescope is possible with the joystick, but will confuse the dome.~~


	~~=='''Taking Images in MaxIm DL'''==~~
	~~1. Wait until sensor temperature reaches set point under Camera Control~~-~~Expose.~~

	~~2. Under Camera Control~~-~~Expose, set exposure time and frame type for a single frame. Hit start. Single frames must be manually saved and will be deleted once the next image is taken.~~

	~~3. Use Autosave to take multiple images. Enter an autosave file name. Use different Slots for images with different~~ settings~~. Click slot number buttons~~, and ~~select exposure type and a suffix to distinguish between multiple slots. The Repeat box controls~~ the ~~number of frames taken.~~

	~~4. The image save path can be found under Options, on the right of~~ the box. ~~Images~~ should be ~~saved to the Z:\ drive~~, ~~and Auto-Subfolder~~ should ~~be checked to save images by date taken.~~

	~~5. Click Save and make sure to hit Start under the Expose tab.~~

	~~6. If two cameras are connected, switch between them by selecting camera 1 or 2 next to the binning information.~~

	~~=='''Disconnecting and Shutting Down the Telescope'''==~~

	~~'''Disconnecting'''~~

	~~1. Under Observatory-Setup, click Disconnect All.~~

	~~2. Under Camera Control-Setup~~, ~~turn coolers OFF and Disconnect.~~

	~~3. Close Maxim DL.~~

	~~4. In TheSky, home the telescope under Telescope-Options-Find Home (~~or ~~double click joystick) and then terminate the link with telescope~~ by ~~clicking the red telescope icon.~~

	~~5. Make sure the dome is Homed, then exit DDW~~ and ~~hit close when the Pin settings window pops up~~.

Jgoodma2 at 19:23, 3 June 2010

2010-06-03T19:23:17Z

← Older revision		Revision as of 19:23, 3 June 2010
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	2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but no saturated. Press Start to begin acquisition. Once Image is exposed. check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods.		2. Open PEMPro. In the Setup tab (one of the lower tabs), connect to the scope and the camera. Switch to the Acquire Data tab, and set the exposure such that the bright star you are pointed at is bright but no saturated. Press Start to begin acquisition. Once Image is exposed. check Maxim DL to make sure it found the star, and not just a hot pixel. Acquire data for a large number of periods.

	3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper right pull down menu. The RMS error in the upper left window may be on interest. This window, along with the analyze data tab in the main window displaying the raw data collected with the correction off on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button. It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since as we will see we can do it in the Refine window.		3. When you have enough periods, click Stop. Save the data, and you will be prompted to create a PE curve, which you should do (if for some reason you do not, at a later point you can load the data into the Analyze tab and click Create PEC Curve there.) Do not worry about any syncing messages. A separate Create PE Curve window will open, and a curve will be fitted automatically. Check to see if any frequencies need to be added; you can reference the Frequency Spectrum from the upper right pull down menu. The RMS error in the upper left window may be on interest. This window, along with the analyze data tab in the main window displaying the raw data collected with the correction off on 06/01/2010 are shown in figure 2. Save the curve by clicking the 'Create Paramount PEC curve' button (Note: throughout the procedure, save and open only text files). It will ask you if you want to open the curve data in a text file, which is unnecessary at this point. NOTE: if a this or any point it asks you to invert the curve, be careful. We determined that we do in fact need to invert the curve, but this is confusing (it is hard to tell exactly what each of the graphs represents: error, correction, telescope offset, star offset, etc.) and it is important to keep track of any inversions. You do not have to invert when prompted, since as we will see we can do it in the Refine window.

	[[File:uncorData.png]]		[[File:uncorData.png]]
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	Figure 2: Raw data with correction off from 06-01-2010 in the analyze tab of the main menu, and the PEC curve creation window fitting a curve to the data.		Figure 2: Raw data with correction off from 06-01-2010 in the analyze tab of the main menu, and the PEC curve creation window fitting a curve to the data.

	4. Close the Create PE curve window. In the main PEMpro window, switch to the Refine tab and and load the curve data (not the original data) you just saved by clicking the 'Curve 1' button. Assuming the curve was not earlier inverted, click the Invert button next to where you loaded Curve 1. We determined (06/02/2010) that when we save a file here, and copy the data into the actual Periodic Error Correction window in The Sky (which does the actual correcting and actively follows the phase of the worm gear) there is a phase offset of 600 units (~66 seconds). On top of that, the zero phase point of the worm gear, as read from the The Sky window, corresponds to about the 15s phase point in PEMpro, requiring and additional 139 unit offset (the math: the worm gear cycle is divided into 1250 units, and has a period of 134.63 seconds. This corresponds to 9.3 units/second). so the total offset we decide don is 740 units. So: using the Shift Curve section at the bottom of the window, shift the curve (make sure the pull down is on the correct curve) to an offset of +740 units (to the right. The maximum shift for each step is 50 units, so this will take some clicks. the recorder of the shift may wrap around to negative values, so you may have to keep track of how far you shifted to the right.) The curve fit from our 06/01/2010 data is shown in the Refine tab in Figure 3, along with its shifted and inverted version. Save teh curve from teh Save section , again selecting the right curve from the pull down. In the save window, select Paramount PEC files (*.txt) from the Save as type pull down.		4. Close the Create PE curve window. In the main PEMpro window, switch to the Refine tab and and load the curve data (not the original data) you just saved by clicking the 'Curve 1' button. Assuming the curve was not earlier inverted, click the Invert button next to where you loaded Curve 1. We determined (06/02/2010) that when we save a file here, and copy the data into the actual Periodic Error Correction window in The Sky (which does the actual correcting and actively follows the phase of the worm gear) there is a phase offset of 600 units (~66 seconds). On top of that, the zero phase point of the worm gear, as read from the The Sky window, corresponds to about the 15s phase point in PEMpro, requiring and additional 139 unit offset (the math: the worm gear cycle is divided into 1250 units, and has a period of 134.63 seconds. This corresponds to 9.3 units/second). Original offset was found by putting a spike in the The Sky correction curve, recording this spike in PEMpro, and then shifting the recorded curve fit and pasting it back into the sky until the spike's matched up. The 15s phase offset we notcied while Acquiring data, by seeing that the The Sky phase mark line passsed its zero point when in the PEMpro window the Current Worm Phase was at 15s. So the total offset we decide don is 740 units. So: using the Shift Curve section at the bottom of the window, shift the curve (make sure the pull down is on the correct curve) to an offset of +740 units (to the right. The maximum shift for each step is 50 units, so this will take some clicks. the recorder of the shift may wrap around to negative values, so you may have to keep track of how far you shifted to the right.) The curve fit from our 06/01/2010 data is shown in the Refine tab in Figure 3, along with its shifted and inverted version. Save teh curve from teh Save section , again selecting the right curve from the pull down. In the save window, select Paramount PEC files (*.txt) from the Save as type pull down.

	[[File:refine.png]]		[[File:refine.png]]
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	Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).		Figure 2: Curve fit from 06/01/2010 in the refine window. Curve 1 is the original curve, Curve 2 is inverted and shifted +740 units (Note that the offset says -510; this is the wrap around).

			Open Notepad, and open the file you just saved. copy the entire thing, and switch back to the The Sky PEC window. Here, click the past button. Your curve should appear in the table window. Click upload to save this curve. In the same window, switch to
	'''Powering up the Telescope'''		'''Powering up the Telescope'''