RA Offset > 45°

[fatwoul]

OK, you know when you think you've done everything right, but something is clearly wrong because things just aren't working? Well, I just had a very disheartening evening.

I was out in the garden with my new MN190 on its new EQ6. I had my laptop with Stellarium with me to double-check locations of stars for alignment, but I know enough star names to get around the sky with my old Vixen GP mount anyway.

I switched the EQ6 on, I input my location correctly, based on a GPS reading (which has been the same since I bought the scope, and I have checked it against other GPS), I set the the date as 06/15/2010 using mm/dd/yyyy, and set the time correctly, making sure to input the time in 24 hour.

So then I was ready to use the polar scope to fine tune the orientation of the mount. Once I input the date and westerly location, I looked through the polar scope and found that all the guide constellations were almost 180 degrees out of place. No big deal, I figured, it must just be set up wrong. So I just spun the scope around so that the stars were in the right positions, aligned Polaris, and made a note to mess with the polar scope later.

The purpose of this evening was to try 3 star alignment. First, I chose Arcturus. The telescope slewed to a very crazy position, pointing into the soil, and asked me to tell it where Arcturus really was. So I did. Same thing with the second star, Dubhe - the scope went to a weird place and I told it where it should go. Last it offered me Vega, slewed somewhere odd again, and I took it to where Vega really was. I pressed ENT, and was given the following message:

RA OFFSET > 45°

It then asked me to check the location, date and time. I did, and they were all right.

What did I do wrong? Surely the mount can cope with being told the telescope is in a radically different orientation to what it expects, since the telescope could be sat in the saddle backwards (deliberately), or there could be a dual scope mount at 90° to normal.

I also don't understand the weird slewing. My expectation was that the telescope would slew somewhere strange for Star 1, somewhere much closer for Star 2, and somewhere very close to Star 3.

It's 1:30am, and I've had to call it a night because I have work tomorrow, but I persisted because I really thought I'd overlooked something obvious. So far, I can't see what that is.

Please help.

[fatwoul]

OK so tomorrow night I'll try the whole Park Position dealy before I attempt alignment.

Live and learn...

EDIT: This doesn't answer the problem with the incorrect orientation of the stars in the polar scope finder, however, so I'd be grateful for any thoughts on that issue.

[Digz]

Hi fatwoul, just a simple thought but you have got the long and lat around the right way and E/W and N/S? I made this error on my first night and the scope was going in all sorts of directions!!!

As for polar aligning, when all the data is entered the handset will tell you the transit and current clock time for polaris. I have found this a much easier way to set polaris in the right position for polar alignment.

[Cornelius Varley]

It could be that you inputted your coordinates in the wrong format. From an earlier post you live in Devon, I have taken the coordinates of Exeter from Multimap and for Exeter, for example, you would input them in the format 3 31W 50 43N.

Peter

[fatwoul]

Thanks guys

Yep, the co-ordinates were/are input correctly (ie the right way around). I'm pretty sure that if I make sure to park the scope at the beginning and end of every session, things will run a lot more smoothly.

Good plan, Digz. Now I just need to learn how to use the handset Polaris location info...

[martin_h]

I always used to use this>>>>>

Free Polar Alignment Software Download Polar FinderScope by Dr. Dale Jason Version 2.04

for allignment.

[Digz]

Parking the scope at the start may be the answer!

As for using the handset to polar align its pretty easy.Its pretty straight forward actually and I found it a lot easier than trying to use the setting circles. Im at work at the moment but hopefully plan to get my scope out tonight, when I do Ill post the procedure I go through.

[fatwoul]

Almost forgot...

When I next order my scope to park, I am concerned it might slew off in some crazy direction. Under such circumstances I normally keep my finger over the ESC button and press it if the OTA looks like it might hit the tripod.

However, is it OK to slew with the RA and/or Dec unlocked? If the telescope is balanced it shouldn't cause any hazards, but would also mean the OTA would just sit still while the motors did their thing. Is that bad?

[Digz]

Providing everything is set correctly the scope, when setting back to the park position, should not crash into anything.

As for working with the RA or DEC unlocked I wouldnt have a clue, my guess would be to have it locked so it prevents the scope from movement out of alignment when observing etc.