Which Goto?

[weixing]

Hi,
I was testing my friend's SkySensor 2000 PC on some issue with a C5 just now... quite impress by it.

I deliberately point the polar axis at around South-East direction... around 135 degree off the north.

After level the mount, I select "Antares" and press GOTO. The mount move and point the scope at the other side of the sky as expected. By using a 12.5mm Ortho eyepiece with 2x barlow, I point the scope back to Antares and press ALIGN... 1 point align. I select "Altair" and press GOTO. The mount move and point the scope at near to Altair... around 5 degree off. I point the scope back to Altair and press ALIGN... 2 point align. I select "Vega" and press GOTO. The scope move and point at very near Vega... in the 1st ring of Rigel QuikFinder... must be less than 1 degree off. I point the scope back to Vega and select ALIGN... 3 point align.

To test the accuracy of the alignment, I select "Jupiter" and press GOTO. The scope move and the Jupiter was in the FoV of my eyepiece... not centre, but around 1/2 way to the edge... I think should be consider very good, because I was using 200x and the FoV was around 0.23 degree (12.5mm Ortho with 2x barlow).

I also like the SkySensor 2000 search or ID function. You can list out all the objects at a certain radius from your scope current FoV, base on objects type and magnitude.

Next time will test the following:
1) Satellite GOTO and tracking function and Satellite Alarm function,
2) GOTO on Moon features function and
3) GOTO on Jupiter's Moons.

Have a nice day.

[VinSnr]

Hi,
I was testing my friend's SkySensor 2000 PC on some issue with a C5 just now... quite impress by it.

I deliberately point the polar axis at around South-East direction... around 135 degree off the north.

After level the mount, I select "Antares" and press GOTO. The mount move and point the scope at the other side of the sky as expected. By using a 12.5mm Ortho eyepiece with 2x barlow, I point the scope back to Antares and press ALIGN... 1 point align. I select "Altair" and press GOTO. The mount move and point the scope at near to Altair... around 5 degree off. I point the scope back to Altair and press ALIGN... 2 point align. I select "Vega" and press GOTO. The scope move and point at very near Vega... in the 1st ring of Rigel QuikFinder... must be less than 1 degree off. I point the scope back to Vega and select ALIGN... 3 point align.

To test the accuracy of the alignment, I select "Jupiter" and press GOTO. The scope move and the Jupiter was in the FoV of my eyepiece... not centre, but around 1/2 way to the edge... I think should be consider very good, because I was using 200x and the FoV was around 0.23 degree (12.5mm Ortho with 2x barlow).

I also like the SkySensor 2000 search or ID function. You can list out all the objects at a certain radius from your scope current FoV, base on objects type and magnitude.

Next time will test the following:
1) Satellite GOTO and tracking function and Satellite Alarm function,
2) GOTO on Moon features function and
3) GOTO on Jupiter's Moons.

Have a nice day.

Can the SS2K do DEC tracking?

I think most GOTO EQ mount only does RA tracking. Why can't somebody come out with an intelligent computer that controls the slewing of both RA and DEC tracking so that we can do away with drift alignment for good?

[river]

Why can't somebody come out with an intelligent computer that controls the slewing of both RA and DEC tracking

Is that what an autoguider do?

Also, I think some software can do that, e.g. The SKY, Stary Night... but do you really carry your notebook out to field as standard equipment?

I made a cable and installed Free Nexstar Observer List to control my CG5-GT from PC, tested ok in my room but never have a chance to use that configuration on the field yet. Can some one install some AC power point at Mersing field?? :mrgreen:

[river]

just in case you ask me where to download, here are some free download and PC control software for your Celestron GOTO system:

http://www.nexstarsite.com/

[VinSnr]

Why can't somebody come out with an intelligent computer that controls the slewing of both RA and DEC tracking

Is that what an autoguider do?

Also, I think some software can do that, e.g. The SKY, Stary Night... but do you really carry your notebook out to field as standard equipment?

I made a cable and installed Free Nexstar Observer List to control my CG5-GT from PC, tested ok in my room but never have a chance to use that configuration on the field yet. Can some one install some AC power point at Mersing field?? :mrgreen:

Autoguider can only guide out minor tracking errors due to the design of the mount. It is not going to help you if your polar alignment is way off.

It is of surprise to me that with today's technology, we still didn't have an intelligent EQ mount that could do away with polar alignment yet able to calculate the alignment error and compensate the RA and DEC drift accordingly so that we can have a EQ mount that is capable of photography without any polar or drift alignment being done. We spent too much time on the alt-azi part but not much was done on the EQ part. Heck, even the Celestron latest Sky align technology works only in Alt-azi mode.

How long more do we have to spend that 30min-1hour setup for drift alignment whenever we use a EQ mount of long exposure?

[weixing]

Hi,

Can the SS2K do DEC tracking?

I think most GOTO EQ mount only does RA tracking. Why can't somebody come out with an intelligent computer that controls the slewing of both RA and DEC tracking

Yes, I think it does (I think the SkySensor can also be mounted on a Alt-Az mount if you can)... or else I can't track the object when I point my polar axis 135 degree off the north. Also, when the mount is not polar align accurately and you set the SkySensor 2000 control mode in RaDec (in this mode the telescope will move along the RA or DEC axis when you press the RA or DEC arrow key), when you press the RA or DEC arrow key, both RA and DEC motors will move in order to move the scope along the RA or DEC axis. But if you polar align the mount accurately, only RA or DEC motor will move when you press the RA or DEC arrow key.

we can do away with drift alignment for good?

For very long exposure astrophotography, I think you still need to use drift alignment even if the mount does both RA and DEC tracking... like the fork mount GOTO, the field rotation will be the main problem, but I think with both RA and DEC tracking, it will take a slight longer time for the field rotation to affect the image for an EQ mount if you do a rough polar alignment.

By the way, the SkySensor 2000 also got another method to get a fairly accurate polar alignment, but I haven't try it yet:
First, do a rough polar alignment, so that the polar axis is points toward the pole. Set the mount mode in the SkySensor 2000 as Unaligned EQ mode and do a 3 star alignment and check that the mount can GOTO accurately. Now select a star (avoid using a star near the zenith) and use GOTO to point to that star. Center the star in the FoV and do a alignment on that star, so that the star will be centered when you press the GOTO. Now, set the mount mode in the SkySensor 2000 as Aligned EQ mode and press GOTO. The star will shift its position if your mount is not polar aligned. Using only the azimuth and elevation adjustment screws on the mount, center the star again in the FoV and the polar axis should be fairly accurately polar aligned. You need to move the tripod if the star can not center in the FoV using the azimuth and elevation adjustment screws, but you need to perform the above all over again.

Have a nice day.

[VinSnr]

I think most GOTO EQ mount only does RA tracking. Why can't somebody come out with an intelligent computer that controls the slewing of both RA and DEC tracking
Yes, I think it does (I think the SkySensor can also be mounted on a Alt-Az mount if you can)... or else I can't track the object when I point my polar axis 135 degree off the north.

But does it track accurately and does the DEC motor actually activated during tracking mode?

Those LXD75 or Celestron ASGT can do GOTO and find objects even if polar alignment is out, but the tracking will slowly go out since only the RA is moving. The DEC motor is only activated during GOTO

[weixing]

Hi,

But does it track accurately and does the DEC motor actually activated during tracking mode?

Those LXD75 or Celestron ASGT can do GOTO and find objects even if polar alignment is out, but the tracking will slowly go out since only the RA is moving. The DEC motor is only activated during GOTO

I think it should, because I remember I put Jupiter in my FoV at 200x and a few minutes later, the Jupiter is still at the same position in my 12.5mm ortho FoV.

Anyway, will confirm again and check the accuracy tonight if I'm free and sky is clear. This time I will use a reticle.

Have a nice day.

[river]

hmm.. maybe it is just me who think like that.

If you know how the two round gears on GEM work, why use GEM if you dont want to do polar align/drift align? Bottom line is no pain no gain for GEM user.

If there is a GEM that can track a star with a far off polar align, I will not use that mount for imaging... To do that, the motors on this mount will not run smoothly, just like how alt-azi mount motor works.

I want my GEM motor to run smooth and steady when I do imaging, and I understand how the polar/drift align helps.

[river]

I wish for such GEM design:

Robotic GEM:
0) Setup telescope with CCD imager.
1) Point it to any star and press start button.
2) The mount will learn how to polar align base on the loaded scope.
2) The CCD capture the drift image of the star for 5 min.
3) Base on the drift image compute the correct polar align position.
4) Turn itself to that correct alignment position.
5) start imaging...

yet another lunch time day-dreaming...