I'm confused with my mount setup?

[wmzaphod]

Hi Guys,

I started off by the book (Celestron GT EQ5) .... pointed the scope 169 degrees south, leveled the mount by the bubble level (built in), set the tilt to my latitude (27.5 ish), did the two star align ........ so, apart from drift align it should be roughly right! - wrong .

Each time I set it up and select the first of the two stars, the scope is pointing well below and to the right of target. So, I move the scope into position and move to the second star - same thing as first, well below and to the right.

However, once aligned to the second, the scope moves between the two alignment stars with a fair degree of accuracy..... Problems start when I want to view another target - usually ends up well off , but will return to either of the alignment stars quite nicely.

No amount of tweaking has fixed the drift alignment tho......

The time, date and timezone are all correct (more correct since I realised the date had to be entered MMDDYY).

So, tonight I went back to basics and ignored the built in bubble level and the tilt scale and I think it was better, tho the initial alignment stars were still well off target.

http://farm4.static.flickr.com/3168/...feb005f50b.jpg

I have some dumb questions....(please see attached image)

Should point "A" (the base of the tripod) be level or should I trust the bubble level? As it stands, when the base is level, the bubble level is way out (lots).

The scale "B" should be set to my latitude, should this correspond to the angle of the scope "C"? I cut a triangle to the correct angles, placed it on the scope and put a spirit level on the triangle..... when this is showing the correct angle, scale "B" shows about 4 degrees higher than it should.....???

So, either I have a mount with two fundamentals completely wrong or I've missed something obvious (wouldn't surprise me none).

I'm also a bit wary of the index marks on the two mount axises, they are just two very dodgy looking stickers. Should I trust them, should the counter-weight arm be vertical at the RA axis start point or pointing about 5 o'clock?

Sorry bout the long winded post but I've been fighting with this for nearly four weeks now and it's starting to get the better of me .....

Would appreciate any advice....

Thanks in advance.

Peter

[CoombellKid]

I'm sure others will chip in and will be able to give you better advice than
me. But I can say two things about my standard EQ5, I've never trusted
the bubble level or the altitude scale.

regards,CS

[wmzaphod]

Originally Posted by CoombellKid

I'm sure others will chip in and will be able to give you better advice than
me. But I can say two things about my standard EQ5, I've never trusted
the bubble level or the altitude scale.

regards,CS

Thanks CS . . . I'm feelin the same.

Pj

[sheeny (Al)]

G'Day Peter,

Unfortunately, with production mounts they are often pretty rough when it comes to the altitude scale and tripod bubble level. If you're lucky you may get one that's close enough, but it sounds like you're not.

If you are prepared to drift align, then you don't need to be accurate with the initial altitude and tripod levelling, but it helps to reduce drift aligning time. But if you just want to do a rough alignment, and 2 star align and straight into observing, then you are probably better off ignoring the altitude scale and use a good spirit level to level your tripod.

Be aware also of magnetic interference on your compass when setting up you scope. Your mount has steel in it, so it will affect your compass. I always walk about 3-5 metres away from my mount and shoot past it to check alignment. Watch out for other things that will affect your compass as well... cars, metal fences, power lines, steel frames buildings, steel sheds, etc.

Al.

[Screwdriverone (Chris)]

Hi Peter,

Yes, I agree, DONT trust the scales.

My Eq2 Skywatcher mount was 6-8 degrees off in the altitude scale. When I was set correctly to Sydney's Latitude, I could not find the SCP.

What I did was to piggyback my binoculars onto the scope and find the SCP using them (and my document about it here helps you identify it) and then man handle the scope by pivoting the tripod on one leg and getting the SCP lined up with the binoculars and then making sure the finderscope and telescope point to the same place by adjusting altitude and direction to get it alll lined up.

Once I did all this, I could see the SCP triangle near Sigma Octanis and the tripod was in the correct spot. When checking the Altitude scale, I noticed it was on 40 degrees instead of 33.5 so it was about 6.5 degrees too low when set correctly.

Other members pointed this inaccuracy out to me so I thought I might pass on the favour. Subsequently when I took the scope and the mount to the supplier, they heated the altitude scale with a heat gun, pulled it off the scope and because it was set correctly, reinstalled it back on to the correct setting and all is fine now.

Moral to the story? Try to drift align and then it wont matter because part of the process involves setting this to correct errors. Or do as I do and place the scope at 168 degrees with a compass and then fine tune to the SCP by finderscope. This now takes me 1 minute to get my scope lined up accurately to the SCP for tracking.

This assumes that you can see the SCP stars as opposed to the drift method which does not need the SCP to be visible.

I hope this helps.

Chris

[wmzaphod]

Originally Posted by sheeny

G'Day Peter,

Be aware also of magnetic interference on your compass when setting up you scope. Your mount has steel in it, so it will affect your compass. I always walk about 3-5 metres away from my mount and shoot past it to check alignment. Watch out for other things that will affect your compass as well... cars, metal fences, power lines, steel frames buildings, steel sheds, etc.

Al.

Hi Al, thanks for the compass advice, the needle moved around quite allot depending where I stood, so I have now marked a point for the rear tripod leg and a point 40 ft away pointing 169 degrees sth.

Originally Posted by Screwdriverone

Hi Peter,

Yes, I agree, DONT trust the scales.

My Eq2 Skywatcher mount was 6-8 degrees off in the altitude scale. When I was set correctly to Sydney's Latitude, I could not find the SCP.

What I did was to piggyback my binoculars onto the scope and find the SCP using them (and my document about it here helps you identify it) and then man handle the scope by pivoting the tripod on one leg and getting the SCP lined up with the binoculars and then making sure the finderscope and telescope point to the same place by adjusting altitude and direction to get it alll lined up.

Once I did all this, I could see the SCP triangle near Sigma Octanis and the tripod was in the correct spot. When checking the Altitude scale, I noticed it was on 40 degrees instead of 33.5 so it was about 6.5 degrees too low when set correctly.

Other members pointed this inaccuracy out to me so I thought I might pass on the favour. Subsequently when I took the scope and the mount to the supplier, they heated the altitude scale with a heat gun, pulled it off the scope and because it was set correctly, reinstalled it back on to the correct setting and all is fine now.

Moral to the story? Try to drift align and then it wont matter because part of the process involves setting this to correct errors. Or do as I do and place the scope at 168 degrees with a compass and then fine tune to the SCP by finderscope. This now takes me 1 minute to get my scope lined up accurately to the SCP for tracking.

This assumes that you can see the SCP stars as opposed to the drift method which does not need the SCP to be visible.

I hope this helps.

Chris

Thanks Chris, I've read your instructions and will give them a go tomorrow night (weather permitting). Tonight I spent time essentially proving the mount markings and level are wrong and I'm now satisfied they are .....

The altitude scale is out by 6 degrees at least and, after lining the scope up using my new south line (marked in the back yard) I performed a 3 star alignment and successfully moved between a number of objects.

I didn't get time to check the drift align tonight but it certainly seemed to be tracking well.

[Tandum (Robin)]

To get it level, I bought a bullseye level from bunnings, leveled my tripod with a real spirit level, then attached the bullseye level to the tripod so it showed level. I'm now pretty confident the tripod is level when I use the bullseye.

[wmzaphod]

Originally Posted by Tandum

To get it level, I bought a bullseye level from bunnings, leveled my tripod with a real spirit level, then attached the bullseye level to the tripod so it showed level. I'm now pretty confident the tripod is level when I use the bullseye.

What a top idea - off to bunnings tomorrow

[[1ponders] (Paul)]

Not knowing the make and model of goto mount at all, your description though does ring a few bells. I imagine being a goto you have to input your longitude and Latitude in the hand controller, are you sure you have the correct sign for the latitude? Do you have daylight savings turned on? How well balanced is your mount? Does the motor sound as thought it is struggling at anytime it is slewing?

Just a few thoughts

[richard omeara]

I always do a 3 star aligment.I have a eq6 and to get it spot on is a really good night.The bubble level in my mount is so far out i dont use it.I also us a adjustible level with angle markings[slanta100 tajima slt-100].Hope this helps a bit.

[wmzaphod]

Originally Posted by [1ponders]

Not knowing the make and model of goto mount at all, your description though does ring a few bells. I imagine being a goto you have to input your longitude and Latitude in the hand controller, are you sure you have the correct sign for the latitude? Do you have daylight savings turned on? How well balanced is your mount? Does the motor sound as thought it is struggling at anytime it is slewing?

Just a few thoughts

Good thoughts - but have checked, double checked and triple checked these, that's why I was gettin so frustrated with it - I wasn't starting on a level playing field.......

It seems inaccurate scales and levels are quite common, has anyone taken it up with the manufacturers or suppliers? it's such a basic part of the mount

Originally Posted by richard omeara

I always do a 3 star aligment.I have a eq6 and to get it spot on is a really good night.The bubble level in my mount is so far out i dont use it.I also us a adjustible level with angle markings[slanta100 tajima slt-100].Hope this helps a bit.

Sounds good, I don't have a level like that so I cut out a triangle with the correct angles, placed on scope and put level on top (works well if you have three hands ).

[asterisk (Geoff)]

Originally Posted by wmzaphod

Each time I set it up and select the first of the two stars, the scope is pointing well below and to the right of target. So, I move the scope into position and move to the second star - same thing as first, well below and to the right.

However, once aligned to the second, the scope moves between the two alignment stars with a fair degree of accuracy..... Problems start when I want to view another target - usually ends up well off , but will return to either of the alignment stars quite nicely.

No amount of tweaking has fixed the drift alignment tho......

Firstly, level the tripod (round bubble level or other). Ignore the bubble on the mount. Align the tripod so that the azimuth adjustment peg is pointing towards polar south. Set up the rest of the telescope (a mounted laser is ideal for the next step.

Start the setup procedure - enter latitude, longitude, time, daylight saving, time zone - select quick setup. Send the telescope to a star near the SCP. Turn on the laser and adjust the azimuth and altitude to bring the laser/viewfinder to this star.

Turn off and restart. Select a 2 star alignment with 3 calibration stars. By the third star the mount will have the object in the centre of the eyepiece.

Have a good night's viewing

Cheers

[wmzaphod]

Originally Posted by asterisk

Firstly, level the tripod (round bubble level or other). Ignore the bubble on the mount. Align the tripod so that the azimuth adjustment peg is pointing towards polar south. Set up the rest of the telescope (a mounted laser is ideal for the next step.

Start the setup procedure - enter latitude, longitude, time, daylight saving, time zone - select quick setup. Send the telescope to a star near the SCP. Turn on the laser and adjust the azimuth and altitude to bring the laser/viewfinder to this star.

Turn off and restart. Select a 2 star alignment with 3 calibration stars. By the third star the mount will have the object in the centre of the eyepiece.

Have a good night's viewing

Cheers

That sounds very logical indeed, so when I turn off do I set the RA and DEC index marks back together?

Peter

[asterisk (Geoff)]

Originally Posted by wmzaphod

That sounds very logical indeed, so when I turn off do I set the RA and DEC index marks back together?

Peter

Yes. Be careful with the DEC index marks - mine were 180° out of alignment (thanks to Matthew g_day on IIS). As you look south along the OTA, the DEC port should be facing you. On mine, if I use their index marks, the DEC port faces south. I used the hand controller to rotate in DEC until the display showed that it had turned 180°. I then put a sticker with a new arrow lining up with the upper DEC index mark on the other side of the DEC housing.

I follow the procedure described in my earlier post every setup and now the objects I select are always in the eyepiece when I slew to them.

Be careful using the on/off switch on the mount - it is not very robust and the cause of many problems for others - I use the on/off switch on my power supply and leave the mount switch permanently on.

My initial acceptance of the quick alignment on the HC is to orient the HC's idea of where things should be with where they are (and get a fairly good polar alignment).

The second alignment (2 star, 3 calibration) really works. One night, out of interest, I added a 4th calibration star - no need - spot on! The procedure does not offer more than 4 calibration stars.

Good luck. Any problems, please ask and I will help if I can.

Cheers

[wmzaphod]

Originally Posted by asterisk

Yes. Be careful with the DEC index marks - mine were 180° out of alignment (thanks to Matthew g_day on IIS). As you look south along the OTA, the DEC port should be facing you. On mine, if I use their index marks, the DEC port faces south. I used the hand controller to rotate in DEC until the display showed that it had turned 180°. I then put a sticker with a new arrow lining up with the upper DEC index mark on the other side of the DEC housing.

I follow the procedure described in my earlier post every setup and now the objects I select are always in the eyepiece when I slew to them.

Be careful using the on/off switch on the mount - it is not very robust and the cause of many problems for others - I use the on/off switch on my power supply and leave the mount switch permanently on.

My initial acceptance of the quick alignment on the HC is to orient the HC's idea of where things should be with where they are (and get a fairly good polar alignment).

The second alignment (2 star, 3 calibration) really works. One night, out of interest, I added a 4th calibration star - no need - spot on! The procedure does not offer more than 4 calibration stars.

Good luck. Any problems, please ask and I will help if I can.

Cheers

Hi Geoff,

Thanks for that, I don't feel such a dummy now and I realise why the scope wasn't pointing where it should........

Cheers

Peter