Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Reverse Leveling iOptron HAZ and other Alt-Az Mounts

Mount Tripod
  • Please log in to reply
1 reply to this topic

#1 RKeating

RKeating

    Lift Off

  • *****
  • topic starter
  • Posts: 15
  • Joined: 17 Mar 2018
  • Loc: Laplace, LA

Posted 22 February 2024 - 08:09 AM

iOptron Alt-Az Mounts have very accurate GoTo pointing when perfectly leveled, but leveling can be frustrating. You may "think" you are level, but if pointing accuracy degrades away from the last object you synced on then you are not level. If we assume the pointing error is entirely due to mis-leveling (it usually is), then my "Reverse Leveling" technique below will improve the leveling and put objects throughout the sky within a high power eyepiece. These instructions were tested with my HAZ46 mount in the Northern Hemisphere but I believe it will work in either hemisphere for any iOptron Alt-Az Mount. After you see the pointing improvement with a perfectly leveled mount, put a level on different parts of your mount to determine the best way to level it in the future. I was surprised to discover that the HAZ saddle was not a good place to level, the best way was to place a level on the Mini-Pier's top surface before attaching the HAZ.

 

BASIS

Sketch 1w - Stars.png

Your tripod is a 3-point support so if one leg is on the South side we can adjust the NE or NW legs to level the tripod in the East-West plane. Once leveled East-West, the South leg will adjust the North-South plane without affecting the East-West plane.

 

Leveling errors cause stars near the East and West horizons to have equal but opposite pointing errors. However if we sync on a star near the East horizon, then any leveling error is nulled near that star but a star on the opposite side of the sky will have twice the leveling error. But we can adjust an East or West Leveler to remove half that error and the mount's East-West plane should then be level. We can then sync on the East or West star and Polaris will have unity leveling error so we can simply adjust the South Leveler to center Polaris and the mount should then be perfectly level in the North-South plane.

 

NOTES:

● When choosing stars to level on, if you do not know the name use a planetarium program (Sky Safari) on your phone to identify it. To quickly find the star in catalog, press LEFT button to position cursor on "tens" digit then use UP/DOWN buttons to jump through list ten-at-a-time until you pass the star’s name, then move cursor to "ones" digit and use UP/DOWN buttons to select the star. Take note of the catalog number so you can type it in on the next iteration.

● The reason we orient the tripod with one Leveler facing South is because when the telescope is pointed at each star, the Leveler to adjust will be near the eyepiece reducing confusion.

● When setting up before dark, use a compass to determine North. After dark use Polaris as North.

● If the last alignment was very bad (maybe you accidentally Synced on a star in opposite side of sky) or if you replaced the Hand Controller's battery, run the ASSISTANT ALIGNMENT WIZARD to program the "Zero Position". Then PARK mount and turn it OFF.

● The mount will not slew through North (prevents Cord Wrap) so the mount may rotate 360° when going to a star in the north such as Polaris.

● If Polaris is not visible, you may use any star in North, preferably near the meridian.

● While not a necessity, a zoom eyepiece is wonderful for zooming in to put star at edge of field for level adjustment and then zooming in to Sync on the star.

● After Reverse Leveling, if pointing is accurate low in the sky but not near zenith it is a "Dobson Hole" caused by misalignment of the telescope's optical axis with its dovetail. If telescope is properly collimated, then this error can only be corrected by placing shims between the telescope and dovetail which is beyond the scope of these instructions.


Edited by RKeating, 22 February 2024 - 02:17 PM.


#2 RKeating

RKeating

    Lift Off

  • *****
  • topic starter
  • Posts: 15
  • Joined: 17 Mar 2018
  • Loc: Laplace, LA

Posted 22 February 2024 - 02:07 PM

REVERSE LEVELING PROCEDURE

● Set up your mount as follows:
    - one Leveler (tripod leg or star leveler) facing South as shown above
    - iOptron logo facing North
    - telescope in saddle pointing North (use compass or Polaris)
    - tripod/pier leveled in the usual fashion
    - mount "Parked Horizontal" and turned OFF

 

● Turn ON and when asked to run "ASSISTANT ALIGNMENT WIZARD" press BACK button.

 

● Choose a star roughly in the East and preferably below 45° in altitude (E-STAR). SELECT AND SLEW > STARS > NAMED STARS then select E-STAR's name and press ENTER to slew. SYNC. TO TARGET then center star in eyepiece and press ENTER to align on it.

 

● Choose a star roughly in the West and preferably below 45° in altitude (W-STAR). SELECT AND SLEW > STARS > NAMED STARS then select W-STAR's name and press ENTER to slew.

 

Sketch 2 - Reverse Level Adjustment.png

● View the star through your finder device while using the Hand Controller's LEFT/RIGHT buttons (but not UP/DOWN) to center the star horizontally. If visible in eyepiece then center it horizontally and increase magnification so that star is near top (or bottom) of eyepiece. If it is too far off to see in eyepiece just use the finder device.  Adjust Leveler closest to EP to move star vertically half-way to center of eyepiece (or finder). SYNC. TO TARGET then center star in eyepiece and press ENTER to align on it.

 

● SELECT AND SLEW > STARS > NAMED STARS then type in E-STAR's catalog number and press ENTER to slew. Use LEFT/RIGHT buttons to center the star horizontally, increase magnification so that star is near top (or bottom) of eyepiece, and adjust Leveler closest to EP to move star vertically half-way to center of eyepiece. SYNC. TO TARGET then center star in eyepiece and press ENTER to align on it.

 

● Go back and forth between the E-STAR and W-STAR, adjusting Leveler then Syncing on star. Use the highest power possible for maximum accuracy. Repeat until it is "good enough" for you. Do not worry about Left/Right pointing errors, this will be corrected when we level on Polaris.

 

● Use Polaris or choose a star roughly in the North and preferably below 45° in altitude (N-STAR). SELECT AND SLEW > STARS > NAMED STARS then select N-STAR's name and press ENTER to slew. If using Polaris, it is catalog# 192. Use LEFT/RIGHT buttons to center the star horizontally, increase magnification so that star is near top (or bottom) of eyepiece, and adjust Leveler closest to EP to center star in eyepiece (not half-way). DO NOT Sync on Polaris.

 

● SELECT AND SLEW to E-STAR or W-STAR (whichever is the shortest slew) then SYNC. TO TARGET.

 

● Go back and forth, leveling on Polaris and syncing on E-STAR or W-STAR until it is "good enough" for you.

 

● Objects throughout the sky should now fall within a high power eyepiece!




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: Mount, Tripod



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics