Zero Point Determination for NEQ6 Pro Goto Mount

[Paliadon]

Hi all, I just received my new NEQ6 Pro Goto Mount for my 10" LX200 Meade ACF OTA and have a query.

I am asked to find my zero point location. I am in Australia (100km North of Melbourne) and my time offset is +10GMT.

According to the book I multiply this by 15 which in turn give me:

10 * 15 = 150

Now, that figure I am assuming is the central meridian for my location. I am now supposed to locate my longitude (145) and subtract the original figure from that which leaves me with 5.

I am now assuming that this means my Zero point equals +5 W and I should set my zero point to +5 W.

Any help would be great guys. Thanks in advance...

[Paliadon]

or should that be 145 (my location) - 150?

Which would give me a -5 which would put me at -5E?

[Merlin66]

Sounds like you're up at at the DSS at Heathcote!!

I don't have the EQ6 but I do have the HEQ5pro which I think is very similar. I have SynScan V3.21 controller.

Where is this "Zero point location" asked for? The set-up I use has never asked for this?

[Paliadon]

Hi Merlin, thanks for the reply mate. No, I am up in Seymour. Not too far away from Heathcote I suppose.

As for the Zero Point, I need this before I even turn the little [removed word] on. It is used to shift the reticule after performing the RA alignment.

[Merlin66]

Is this mentioned in the manual for either the mount or the Synscan????

I had a look through the documentation I have and couldn't see anything.

If I understand, it's basical working out the local sidereal time correction. The difference between the AEST -10hr (150deg longitude) and your actual longtitude. So if you're less than 150 you should subtract, more than 150 add.

Hope this helps.

[Astro_Baby]

I think your referring to the longitude offset for the polarscope.

The longitude offset was always used in an age when you had to calculate the time offset based on a transit of Polaris at a given time for a given longitude.

Its not really needed. Use the polar finder program (http://24.237.160.4/files/Astronomy/software/Polarfinder/) and that asks for your longitude. Find a transit time for Polaris and use that as the base data for your polarscope setting circles OR alternately just use Polarfinder to see where Polaris should be.

I always set the polar setting circles up because it saves me having to lug a PC about with me.

I wrote a guide for the HEQ5 polar alignment procedure - its located here Astro Babys HEQ5 Polar Alignment for Idiots Page - its the same procedure for the EQ6.

Hope thats of help to you.

Oh the bit you are most likley looking at is;

From the Sky-Watcher manual:

The alignment procedure requires that you set the Longitude scale to "Zero".

Depending on where you live, "Zero" can be anyplace between the E and the W on longitude scale, so first you need to determine where zero is for your location.

Your Zero point is equal to the difference between your actual longitude and the longitude of the central meridian of your time zone. To calculate the longitude of your central meridian, multiply your time zone offset from Greenwich Mean Time (GMT) by 15. For example, in Waterloo, Ontario, Canada (Eastern Time) the time zone offset is -5 hours. Ignore the sign and simply multiply 5 x 15 = 75.The longitude of the central meridian for the Eastern time zone is 75 degrees west. The actual longitude at the viewing location in Waterloo is 80 degrees 30 minutes West. Ignore the 30 minutes and just use 80 in the equation. Now it's simple, 80 - 75 = 5. Since 80 is greater than 75 the result is positive 5. That means Waterloo, Ontario is west of its Central Meridian. In this case, the zero point is at the "5" mark on the W side of the scale. If the location was east of its central meridian the equation would yield a negative value. In that case the E side of the scale should be used.

Its for setting the 'zero' for the date circles zero position.

[Kook]

Hello,

I'm new in the forum. I have got also a NEQ6 pro mount. I would like to set my RA and date circles to polar align the mount.

I tried all guides on the internet but could not find one that works with the NEQ6. Even the very good guide of astrobaby for the HEQ5 does not apply with the NEQ6 : indeed the NEQ6 does not have the same mechanisms for the date circle then the HEQ5. In the astrobaby guide there is an operation where you need to align the hour of observation (from the RA circle, moving the RA axis) with the date of observation read on the Date circle. It is just impossible to do that on the NEQ6 as the date circle moves synchronously with the RA circle (when rotating the RA axis). Furthermore the two circles are a long distance apart so even it the move was physically possible it would be very inaccurate.

I need help from someone who has set the date circle on a NEQ6 and how to do it please ?

Thank you

[Astro_Baby]

Yes - - I also have an EQ6 and its tough to do. The machniasm is in fact exactly the same but the EQ6 RA circle is worse. Mostly because it doesnt lock at its zero point very easily.

There are two tings you can do -

1/ Strip the mount to bits and remove the grease from the RA woem wheel which will allow the RA circle to lock properly. It is however mles from the polarscope circle so its tough to align.

2/ Use the hour angle method. This involves rotating the RA until Polaris is at the bottom of the reticule. Thats your polar transit. Now set the RA scale to 0.

Lets say your polaris tables indicate that the hour angle is 5 hours. SImply rotate the RA on the scope until 05:00 shows against the index mark - basically the HA number tells you how lonh since Polarius transited.

I assume your mount is GoTo so you could either use the closk position (simplest of all) the Synscan will tell you what the clock poistion is (ie 7pm) and you then just rotate the RA until Polaris marker is at the 7 o clock position. SIm,ple as that OR the SYnscan handset gives you the hour angle during alignment and you use the hour angle method.

Personally I find the HA angle methid prone to hiccups because on the HEQ5 the TA scale tends to stick and on the EQ6 it tends to slip.

As regards doing it with the circles the methid is identical on the EQ6 to the HEQ5 - its just the circles arent in a great position to easily match the RA circle to the polarscope date circle.

[Kook]

Yes, thanks. I understand the RA circle setting is very easy with HA indication or even simpler the clock position. I have indeed used polarfinder for that or the synscan computer indication.

But I like to understand in details all the equipment functionality. And I have a problem to understand it with the date/longitude circle. In theory it should be possible to use just the current date and time of observation, set the current date by turning the date circle (let's forget for the moment the longitude E-W correction not to make things even more difficult), set the current time on the RA scale and this should bring my mount perfectly aligned with the NCP. Assuming I'm not wrong in that belief, how (and why) should I calibrate the date circle in the right position (once for all ?, once every year ?, every month ?)

I understand that the date circle divides 360 degrees rotation in roughly 360 days of the year as the earth rotates in one year around the sun and comes back to its initial position after a full spin.

This is thus logical that the polaris (NCP) position shall also rotate with the date. But further than that I do not know how to calibrate this circle (and then use it afterwards. I tried your method but the end result was a polaris position in the polar finder totally missed)

[Astro_Baby]

No idea why following m method fails, works for me every time.

How often should you set the circles up....answer..no idea. As the gauge isnt very accurate and doesnt take into account leap years I would guess set it up as often as seem necessary. I used to do it once a month but these days I don bother. As an observer its accurate enough and most times when. Have been out dor prolonged periods its satisfying to watch polaris track round the circle suggesting all is well.

The time offset I have never bothered to worry about, as i live almost on the gmt meridian there would be little point