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Jonny14716

Which mount should i buy?

29 posts in this topic

FYI

 

I dont now if this is still true on the latest firmware(it was v3.35) or V4 handsets as I dont use a handset any more but there was a few caveats with the Polar Alignment using the handset as Stephen, of EMS fame, pointed out here https://stargazerslounge.com/topic/197302-synscan-v335-polar-alignment-optioncant-be-this-easycan-it/

As I say don't know if they still apply.

Plus the Sharpcap does not rely on the Handset or the AZEQ6GT being powered up as it just does it via the AZ/ALT bolts and the actual image of the stars.

 

Which ever method you use enjoy and clear skies.;)

 

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Well I have a V4 handset and the procedure is described in there. I did love Celestrons all star polar align on my CGEM, from what I've read so far (although must admit I'm yet to actually try it) it seems a little more awkward than that. 

 

With regard to the sharp cap method... would that not rely on the OTA and polar access being in perfect alignment (cone error?) in order to be accurate? 

 

Obviously all suggestions are welcomed as it is a new mount to me so all you guys input is appreciated. 

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2 hours ago, Jonny14716 said:

Well I have a V4 handset and the procedure is described in there. I did love Celestrons all star polar align on my CGEM, from what I've read so far (although must admit I'm yet to actually try it) it seems a little more awkward than that. 

 

With regard to the sharp cap method... would that not rely on the OTA and polar access being in perfect alignment (cone error?) in order to be accurate? 

 

Obviously all suggestions are welcomed as it is a new mount to me so all you guys input is appreciated. 

It is said that the OTA or Sharpcap camera does not need to be in perfect alignment as the maths solves the problem for PA - quotes the below from discussions on Polemaster but its the same for Sharpcap (so I am led to be believe). People triad polemaster in other positions other than where the Polar adapter puts it (in the scope scope hole).

The following is from Sharpcap web site:

"

Any Tips?

Try using a guiding camera (ZWO120MC, QHY5LII, Altair GPCAM, etc) with a ~200mm focal length finder-guider - this will give the correct field of view.

Read the on-screen instructions - they will walk you through the procedure!

Select a high gain and an exposure of 4-8s - this should let SharpCap see enough stars.

If your mount is on a pier, the pier mounting plate bolts can often give finer adjustment than the mounts own alt/az adjusters.

You don't need to worry if your scope or finder is aligned with the mount correctly - misalignment won't affect the result."

 

This is from Cloudynights - about Polemaster but the logic is the same.

 

"I will try to explain why it doesn't really matter where the OTA/PoleMaster is *pointing...Lets say you point your OTA arbitrarily to a star in the north-east i.e. nowhere near the celestial pole and do a plate solve. The centre of that plate solved image will be at some RA and DEC coordinate. Now rotate your mount in RA 12 hours on, it will now be pointing in the north-west, and again do a plate solve. The centre of this second solved image will tell you where the mount will be pointing in 12 hours time. The centre of rotation between the two plate solved images can be calculated using geometry (spherical coordinate geometry).

 

If the second image's DEC angle (ignore RA for now) is exactly the same as the first one, then the rotation of the RA axis is perfectly polar aligned (and hence the mount) as it precisely follows the declination angle through 180 degrees...if however it doesn't match then a correction needs to be made (usually 1/2 the error). The error will most likely be in both RA and DEC which will translate into physical mount adjustments in Alt/Azi using the mount's bolts."

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13 hours ago, stash said:

It is said that the OTA or Sharpcap camera does not need to be in perfect alignment as the maths solves the problem for PA - quotes the below from discussions on Polemaster but its the same for Sharpcap (so I am led to be believe). People triad polemaster in other positions other than where the Polar adapter puts it (in the scope scope hole).

The following is from Sharpcap web site:

"

Any Tips?

Try using a guiding camera (ZWO120MC, QHY5LII, Altair GPCAM, etc) with a ~200mm focal length finder-guider - this will give the correct field of view.

Read the on-screen instructions - they will walk you through the procedure!

Select a high gain and an exposure of 4-8s - this should let SharpCap see enough stars.

If your mount is on a pier, the pier mounting plate bolts can often give finer adjustment than the mounts own alt/az adjusters.

You don't need to worry if your scope or finder is aligned with the mount correctly - misalignment won't affect the result."

 

This is from Cloudynights - about Polemaster but the logic is the same.

 

"I will try to explain why it doesn't really matter where the OTA/PoleMaster is *pointing...Lets say you point your OTA arbitrarily to a star in the north-east i.e. nowhere near the celestial pole and do a plate solve. The centre of that plate solved image will be at some RA and DEC coordinate. Now rotate your mount in RA 12 hours on, it will now be pointing in the north-west, and again do a plate solve. The centre of this second solved image will tell you where the mount will be pointing in 12 hours time. The centre of rotation between the two plate solved images can be calculated using geometry (spherical coordinate geometry).

 

If the second image's DEC angle (ignore RA for now) is exactly the same as the first one, then the rotation of the RA axis is perfectly polar aligned (and hence the mount) as it precisely follows the declination angle through 180 degrees...if however it doesn't match then a correction needs to be made (usually 1/2 the error). The error will most likely be in both RA and DEC which will translate into physical mount adjustments in Alt/Azi using the mount's bolts."

 

That makes sense. Might have to give it a try and see how it works out. 

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