How do I quickly start my Celestron telescope? Can I use previous alignment information?
November 24, 2010
If you want a fast start for your scope to track without bothering to go through the entire alignment routine, there are a number of functions available. It depends on what Celestron mount you have. All the options below are available if you have one of our German equatorial mounts (CGE, CGE Pro, CGEM, or Advanced GT). The options are similar on a wedge-mounted Alt-Az telescope (NexStar SE or CPC). Hibernation is found on the NexStar SE, CPC, NexStar SLT, LCM, and GT Alt-Az mounts, while the only Alt-Az mounts that have the Set Mount function are NexStar SE and CPC.
Option 1: Tracking only
Here, we will use the CGE as the example mount.
- Power on the mount. When the hand control says “CGE Ready,” press the Menu button.
- Now scroll through the options using the 6 or 9 key to find Tracking. Press Enter and scroll again to choose Mode. Press Enter, then choose either EQ North or EQ South. The RA motor will start and track in the right direction.
- The tracking rate can be set to that of the Sun, Moon, or stars. Under Tracking, choose Rate, then choose either Lunar, Solar, or Sidereal.
The hand control has no idea where the scope is pointing when Tracking is used, so none of the GoTo functions will work. No information from previous alignments is used here. Alt-Az mounts won't track by simply choosing Tracking; they must either be aligned or use the next option: hibernation.
Option 2: Hibernate
Hibernate allows you to retain the alignment of your scope when it’s completely powered down. Use it if you know the mount won't be disturbed between observing sessions. It's found under Utilities > Hibernate. You’ll be prompted to move the scope to a convenient position. Do this using the hand control. Don’t loosen the mount’s clutches or otherwise move the mount. Press Enter. Finally, the display will ask you to turn off the power.
When you power up the mount, you’ll wake it by pressing Enter (or cancel the hibernation by pressing Undo). If the mount has no real-time clock (RTC), the RTC is turned off, or there is no attached or enabled GPS, then the hand control will ask you for date and time information. After that's entered, the top level prompt “CGE Ready” will be displayed. The previous alignment is fully restored. The pointing accuracy should be the same as before the mount was turned off. If the scope has been turned off a long time, the hibernated alignment can lose accuracy and you may need to realign the scope. In this case, press Undo when powering up and the mount will display the usual alignment options.
The Hibernate mode allows you to retain the alignment of your scope when it’s completely powered down. However, it’s not perfectly accurate and the accuracy decreases with the amount of time the scope has been asleep. So you may need to realign the mount, especially if it's been hibernating for some time.
Option 3: Last Align
If you failed to hibernate the mount before turning it off, and/or it was necessary to reorient the mount using the clutches, then you can still use your previous alignment using Last Align. Power up the mount and start the normal alignment procedure. Find the switches (index marks on a CGEM/Advanced GT), then enter the time and location (if necessary). When asked to select the alignment method, choose Last Align. The mount will use its most recent alignment parameters, plus its knowledge of where the switches (index marks) are for restoration of the alignment. Pointing accuracy will be slightly diminished relative to the hibernation option.
Option 4: Quick Align
Quick Align doesn't require a previous alignment. You start the mount normally, entering information as needed. When it's offered, choose Quick Align from the Select Alignment menu. The hand control will display “Alignment Successful.” The mount assumes perfect polar alignment and that the switches (index marks) have left the OTA pointing at the celestial pole. Your pointing accuracy will depend on the validity of these assumptions.
Option 5: Set Mount Position
Set Mount Position is another mount function involving quickly restoring alignment. Unlike the restoring options above, it's used during one observing session where the mount is not turned off. It's handy when reconfiguring: rebalancing your scope or to change cameras or accessories that require you to move the mount, lengthening/shortening tripod legs, etc. You’ll be able to recover some of the original pointing accuracy by using it. Before you’ve moved or reconfigured your scope, find a bright star in the named star list and GoTo it. Press Utilities then scroll to Set Mount Position. The hand control will prompt you to center the star in the finder--press Enter once it is--and then to center it in the eyepiece; once it is, press Align. A Sync message will finish the operation. After moving the scope/reconfiguring, just recenter on the same star and the maintained alignment will be used by the mount.
If necessary, you can now more easily slew to and find new alignment stars to replace the old ones by pressing Align and using the Alignment Stars option there.
If possible, the best accuracy is preserved by pointing the mount to a bright star before reconfiguring it, then repositioning the mount and tube to close to original position and pointing again to the same star and using it for the Set Mount Position.