Post by howie1 on Aug 6, 2017 12:38:21 GMT
Couple of tips which save a bit of time for both EQ goto and AltAz goto mounts:
EQ Mount:
NOTE! Do not do the following if you have a pier setup, or have a fixed pre-polar aligned rig. Only do the following if you use a fully portable rig - IE you carry the tripod with you and plonk it down based on a compass directions for the pole, etc, etc.
Do the usual ... level the tripod, place the OTA in the HOME position before powering it all up (DEC at 90 degrees, RA / head vertical).
Then, when you start your star alignment process and it goes to the first star in your (2, 3 or more) alignment process, if you center that first star using the Alt and Az bolts you are (in effect) doing a much more accurate polar alignment than you first did using a compass for AZ and an inclinometer or used the ALT settings scale on the mount. Use the hand control direction buttons to center the other 2 or 3 or more stars in the alignment process, but that first one can be done by Alt AZ bolts.
AltAz Mount:
It costs $AUD190 in Australia, but $USD100 if its cheaper for you to buy from the USA, but the digital level in the link below is accurate to a tenth of a degree. BTW there's some small $30 ones which claim this on eBay, but I can't vouch for them. The cheapest alternative is your smartphone level app's which are at best accurate to one degree, but that's all you need to get to for the first star alignment.
Most people don't level an AltAz mount, preferring to just rely on the star alignment process to (in effect) level and find North by adjusting the in-built star map for your skies. When you first move the OTA around trying to line up the first alignment star it is often hard to point it at the first bright star. People tell you to sight down the centre of the OTA towards the star to move AZ, and then down the centre of the edge of the OTA to move ALT, then try to find the star in the finder.
The quick way is first to slew to anywhere within 20 degrees or so of the stars direction, then use your digital level on top of the OTA to set it to the ALT of your target star (from any stellarium app). That effectively eliminates one of the variables ... the first stars ALT is now set to within 1 degree (smartphone), or better (using the fancy expensive digital level below). As the finderscopes FOV is 6 degree's, if you now ONLY use AZ direction button to slew left or right in AZ, the star is sure to pop into the FOV of your finder.
NOTE ALWAYS slew to within 20 degree's before using the level on top of the OTA. Why? Because the mount is not level! Lets say it's tilted 10 degree's upwards at the starting point and you use the level on top of the OTA at that point to set 40 degree's (say). Then you slew 180 degree's. The mount at that point will be sloping DOWN 10 degree's which means the 40 degree's you set with the level is now only 20 degree's ALT in that direction. Draw yourself a little diagram to see thats true So always slew close to the direction of the target star FIRST, then set the ALT using the digital level.
www.justtools.com.au/smarttool-digital-module-only-519752
EQ Mount:
NOTE! Do not do the following if you have a pier setup, or have a fixed pre-polar aligned rig. Only do the following if you use a fully portable rig - IE you carry the tripod with you and plonk it down based on a compass directions for the pole, etc, etc.
Do the usual ... level the tripod, place the OTA in the HOME position before powering it all up (DEC at 90 degrees, RA / head vertical).
Then, when you start your star alignment process and it goes to the first star in your (2, 3 or more) alignment process, if you center that first star using the Alt and Az bolts you are (in effect) doing a much more accurate polar alignment than you first did using a compass for AZ and an inclinometer or used the ALT settings scale on the mount. Use the hand control direction buttons to center the other 2 or 3 or more stars in the alignment process, but that first one can be done by Alt AZ bolts.
AltAz Mount:
It costs $AUD190 in Australia, but $USD100 if its cheaper for you to buy from the USA, but the digital level in the link below is accurate to a tenth of a degree. BTW there's some small $30 ones which claim this on eBay, but I can't vouch for them. The cheapest alternative is your smartphone level app's which are at best accurate to one degree, but that's all you need to get to for the first star alignment.
Most people don't level an AltAz mount, preferring to just rely on the star alignment process to (in effect) level and find North by adjusting the in-built star map for your skies. When you first move the OTA around trying to line up the first alignment star it is often hard to point it at the first bright star. People tell you to sight down the centre of the OTA towards the star to move AZ, and then down the centre of the edge of the OTA to move ALT, then try to find the star in the finder.
The quick way is first to slew to anywhere within 20 degrees or so of the stars direction, then use your digital level on top of the OTA to set it to the ALT of your target star (from any stellarium app). That effectively eliminates one of the variables ... the first stars ALT is now set to within 1 degree (smartphone), or better (using the fancy expensive digital level below). As the finderscopes FOV is 6 degree's, if you now ONLY use AZ direction button to slew left or right in AZ, the star is sure to pop into the FOV of your finder.
NOTE ALWAYS slew to within 20 degree's before using the level on top of the OTA. Why? Because the mount is not level! Lets say it's tilted 10 degree's upwards at the starting point and you use the level on top of the OTA at that point to set 40 degree's (say). Then you slew 180 degree's. The mount at that point will be sloping DOWN 10 degree's which means the 40 degree's you set with the level is now only 20 degree's ALT in that direction. Draw yourself a little diagram to see thats true So always slew close to the direction of the target star FIRST, then set the ALT using the digital level.
www.justtools.com.au/smarttool-digital-module-only-519752