AZ Gti alignment query

[Jay_B]

Hello everyone,

I have recently started to use a Skywatcher AZ Gti with a small Maksutov 102mm ( OTA=2kg approx ) in AZ mode (using the Synscan Pro App) with various eyepieces with some success.

All my observing is from a small balcony facing SW. Polaris is blocked by the house and magnetic compass bearing is iffy due to steel in parts of house  above window.

For a North Level alignment , can anyone give me an idea of how accurately the telescope must aligned to true North at the start of the alignment procedure ?

Thanks...

[Gfamily]

1 hour ago, Jay_B said:

Hello everyone,

I have recently started to use a Skywatcher AZ Gti with a small Maksutov 102mm ( OTA=2kg approx ) in AZ mode (using the Synscan Pro App) with various eyepieces with some success.

All my observing is from a small balcony facing SW. Polaris is blocked by the house and magnetic compass bearing is iffy due to steel in parts of house  above window.

For a North Level alignment , can anyone give me an idea of how accurately the telescope must aligned to true North at the start of the alignment procedure ?

Thanks...

If there is an obvious landmark you can identify from your balcony, you should be able to use a map to calculate its bearing (angle from True North) - with this, you can set a datum line for you to use. It should be close enough. 

Basically, when using North/Level, the mount moves to where it expects the first alignment star to be - when you adjust to get the first star centred, that gives the mount the correct offset to negate any inaccuracy in the North Level position.   

[PEMS]

I would say that with a Mak it needs to be initially pretty well aimed at North (NCP). Luckely magnetic North and NCP are close to each other for the UK.

Reason is that the focal length of a Mak means a fairly narrow view at the eyepiece and the mount starts out assuming that it is perfectly aligned and slews to the first alignment star on that basis. If you are 1 degree out then the first alignment star is likely out of vision and you probably don't know which way you have to move.

A well aligned finder helps.

As ever the better set up the easier your life will be. So try and determine North as best you can and align the finder as accurately as you can. It is worth a bit extra time.

I gave up with a Mak I had because of the alignment -  and a quirk with the mount.

[Jay_B]

Thanks Gfamily,

There are some landmarks visible at night near the horizon and so I will use an OS  map to calculate the datum bearing as per your suggestion. I have also realised that by carefully loosening the bolt at the base of the extension tube and then slowly turning the extension tube the telescope can be aligned to the datum bearing without rotating the tripod after an approximate "North"-Level starting position. This should align the telescope bearing shown in the app to the landmark datum bearing.

[SuburbanMak]

You’ve a great combo there!
I’ve been using the AZGTi for two years with Mak 127 and always found North Level the most accurate alignment option. 
I found accuracy improved dramatically when I took proper care around levelling the tripod at the start of set up - if your initial North positioning is close but slightly off then as others have commented the mount’s model will refine as you manually confirm the alignment stars, however if the mount is less than perfectly level, all it’s calculations will be off.   Of all my alignment steps I take the longest on initially levelling the tripod and never regret the extra five minutes or so of fiddling! 

Ditto the advice on finders there too - the Mak’s relatively narrow field can be mitigated with a decent finder, I use both an 8x50 RACI and a Telrad (which looks a bit silly in the 127 but does the trick, with the smaller 102 you might do better with the lower profile Rigel Quickfinder or the supplied RDF, key thing is to add an additional optical finder). 

[Jay_B]

Cheers SuburbanMak,

Will definitely heed your good advice on levelling the tripod and mount and  using a viewfinder scope plus Rigel Quickfinder. I have a Rigel Quickfinder and so I will attach a spare bracket for this purpose 🙂

[SuburbanMak]

You have a super portable setup there - one of the things I love most about my Mak is it’s ruggedness, well worth popping into a backpack and finding an out of town spot that is darker - makes a huge difference to what can be seen. 

[Gfamily]

In the last 6 months I've appreciated the value of Point and Track on the AzGTi (though this does rely on the value of a well aligned finder).

This is useful if you can find something comfortably without alignment, you can then tighten the clutches and in the app select the "Point and Track" option. It'll then track with reasonable effectiveness. 

I have to say it's easier to do with my refractor, as it has a wider field of view.

Edited January 31, 2023 by Gfamily
remove duplicated clause