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Chris Rowland

Celestron StarSense Accessory

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3 hours ago, 1CM69 said:

Brilliant, I am very interested in how you get on with slewing limits using the StarSense on a EQ mount. 

Since I bought my StarSense the weather has been terrible and haven't had any chance to try it. 

Just did a bit more checking and realised that the Starsense controller has a wedge option.  I had aligned with Wedge set to off in the hand controller.  My slew limits were not working at all and I realised from the on screen information that the altitude was reading way off... Polaris was showing at 88 degrees ALT and was throwing a slew warning when selecting it. (in my location Polaris is actually at 52 degrees ALT). All my location information is fine and is set by the internal GPS.

I have now set the Wedge option to on and will be re-aligning tomorrow.  Interesting though that even with wedge option off, the pointing seemed fine from my first alignment attempt.  

EDIT: now I know why Polaris is reading 88degrees... ALT in the hand controller relates to the relative position of the OTA to the forks... at Polaris it should read 90degrees, not 52degrees)...more digging on slew limits...  As Celestron fork mounts set the altitude limits based on the relation of the OTA to the forks, NOT the actual altitude of the object you want to slew to, on a wedge the slew limit minimum of 0 is different for south / north (and actually at every point of Azimuth).  At my location of latitude 52degrees, on the North side a 0 minimum limit actually means -38degrees and on the south side it means +38degrees.  As Starsense is limited to 0 to 90 and does not give options for direction, I believe this means that slew limits are only useful for avoiding hitting the mount with image trains that are longer than the fork clearance by using the max limit.  Min slew limits are pointless (unless using hyperstar I guess), and in fact somewhat annoying because the scope can not slew to less than 38degrees on the south side without a warning. 

Edited by JayStar

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Managed to get an hour in with Starsense before the fog rolled in here in the Midlands.

I redid my 10 point model after setting the wedge option in the handset.  Used 10 fresh manual points and all solved, mostly with 100 stars.  Then set these 10 points as the user auto option.Then performed centre calibration - instead of using coarse and fine centre calibration with eyepieces I just used my red dot finder to align the star (not as good but just wanted to try it out).Then realigned as prompted after centring ... couple of cord wrap issues caused a problem with 3 of the 10 points on this final alignment, but was pleased to see that the process went back and redid the points that failed and solved them.

Did not do a polar align yet - that is next on the list.

Managed to get two slews in before the fog rolled in and both Polaris and Mira were on the DSLR chip (both about half way from centre to the right of the chip, and slightly higher than centre vertically).  This was at F/10 , 2.35m focal length (CPC925).  That's not bad at all considering I didn't use eyepieces for the centring.

I'm impressed.

Another note on slew limits - I did not get any warnings for the slew to Mira which was at about 26degrees altitude (less than 90degrees angle from the fork to ota pointing south), or the slew to Polaris. Slightly confused by that, I am thinking that once aligned with the wedge option the slew limits are understood after all. 

 

Edited by JayStar
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I finally had a chance to use my SSA last night, albeit only in AltAz configuration. 

The observable sky in my back yard is very limited & I had 3 failed auto aligns to start with before I tried a manual align which succeeded. 

I then did the procedure to align the SSA to the scope & attempted the realign but the sky clouded out, so a fail there. 

A bit later I attempted another auto align & this time success but it took quite a while because of my limited view it kept slewing and facing the wall of my house. 

I did notice that at times it would slew to a point slightly lower than the index marks, not sure why it does that. 

Overall I was quite impressed and can see the potential given a wider view than I have. 

I cant wait to try it in the open and wedge mounted. 

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Last night I tried out the SSA with my scope wedge mounted & here's a summary of the process.

Within in minutes of starting the auto align process I got success making sure I had wedge setup set to YES.

Then it was time for Center Calibration of the camera, this bit for me was a problem.

The first part of the calibration (coarse) says to center star in finder before the EP, I misread this and used the HC to centre in the finder & noticed that my finder must have been ever so slightly out of align with my scope as the star was not exactly central in the EP so I used the HC to centre star in EP instead. (I was using a 40mm EP at this point)

The next step of the calibration (fine), I change the EP to my 12.5mm cross-hair to get the star much more centered & hit align.

The system solved the alignment & warned me that the difference was huge, +5000 odd in one direction and that the SSA bracket must be out of true, it isn't so I just excepted the findings.

Next was the normal re-align process which now failed 3 times, on one occasion I had to quickly stop the process as the scope was slewing way below the horizon and the dew shield came in to contact with the scope's base.

I set the scope back to index align marks and pointing south to fully restart alignment process, yet another fail.

I then reset the HC to factory, put scope to index & pointed south, did auto align with success.

Now back to calibrate center, this time in coarse setting I just concerned myself with the centering in the finder and seeing that the star was at least in the FOV of the 40mm EP & then hit enter.

Fine calibration next, here I swapped my EP to my 12.5mm cross-hair and centered the star, pressed align, got a lot smaller reading +608, +246.

Did the re-align, and success.

I slewed to Polaris, slight tweaking needed but here I used the wedge adjusters and then did another Center Calibration & re-align with success.

I slewed straight to M31 & it was bang central in the finder but ever so slightly below centre in the 12.5mm EP, that I could live with.

So although the instruction guide as usual leaves a lot to be desired, the SSA is usable while wedge mounted. I did get a below slew limit warning when slewing to Venus that was close to the horizon but actually still within what should be -39 degree lower slew limit for my latitude, so that still needs figuring out.

Anyway, with so much moisture in the air any hope of imaging with my scope was quickly given up on & I resigned myself to visual.

Then I decided to piggyback my dSLR on the scope to use it for tracking for some widefield images and was extremely happy with the results I got from a very stable track, see here: 

 

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On 12/28/2016 at 06:05, 1CM69 said:

A bit later I attempted another auto align & this time success but it took quite a while because of my limited view it kept slewing and facing the wall of my house.

There is some way to set it to take the 3 pictures at YOUR CHOSEN locations, rather than the 3 default locations.

I have not done this myself however as I did not need to.

Suggest you have a read-up on the latest starsense manual pdf from Celestron support website as this will have the instructions to follow.

Celestron keep updating the pdf manual and the paper ones are well out of date!

 

 

 

Edited by alanjgreen

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On Thursday, December 29, 2016 at 14:11, alanjgreen said:

There is some way to set it to take the 3 pictures at YOUR CHOSEN locations, rather than the 3 default locations.

I have not done this myself however as I did not need to.

Suggest you have a read-up on the latest starsense manual pdf from Celestron support website as this will have the instructions to follow.

Celestron keep updating the pdf manual and the paper ones are well out of date!

 

 

 

What I have noticed is that at unobstructed wide sky locations StarSense auto-align always replicates the same THREE basic movements. It doesn't matter which direction your (home) OTA start point is, the same trio of movements is replicated.

At my home,  it was initially intuitive to aim my OTA due South in its 'home' position as that is the least obstructed horizon. But this required an extra OTA movement  because of an obstruction (my house) on the third movement. As you can point the OTA at any horizon, I progressively tried different 'home' directions as my start point.  Some were worse requiring five Starsense movements.  But I discovered that if I somewhat illogically aimed my OTA at a brick wall, I then got the fastest of all three point alignments as I had helped it find the three most unobstructed sectors by a carefully chosen start point.

Even with a wedge/polar align via Starsense you start with a normal align. So simply work out your best 'home' position and aim at that horizon. You do not have to start with North.

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I just looked in the latest pdf and with the latest software you need to perform "starsense user auto align" as a once-only task to customize where the unit chooses to take its three pics

page 13 of the latest manual says ...

 

user.jpg

http://www.celestron.com/media/1317936/94005_starsense_autoalign_manual_february2016.pdf

Edited by alanjgreen

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True Alan where the obstruction problem is extreme, but I reckon an auto align is easier where there are a merely a  few obstruction issues. It just needs a bit of patience to work out your best OTA start point (e.g. which direction).  After a couple of attempts (e.g. watch the OTA movement) this will become obvious.

Most people start by aiming North or at their widest sky vista as that is what they  have read. Neither are necessary as Starsense doesn't care about its start point. It just wants to find three unobstructed sky sectors. 

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Hi my sky prodigy hand set goes through the motions to initiate then the screen goes blank back light still on though.

Is there a way of  using the buttons to reset it back factory setting  tried pressing 0 when rebooting.

cannot get into the menus at all.

thanks

dick

 

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Hi all

I am new to astronomy having been bought a Celestron Evolution 6 as a 60th birthday present, I have used the scope only a couple of times via an ipad Pro and Sky Safari 5 and have ordered a Star sense unit to make alignment easier. Will I need to input location and time details or will it pick these up from the ipad? 

Can you also advise me on what the second part of this quote regarding index marks, means from the manual?

1.  Set your telescope up with an eyepiece and position the telescope in its home position or index marks . Equatorial mounts should be roughly polar aligned, but precise polar alignment is not  required . Alt-Az mounts should have the altitude aligned to its index marks with the tube level to the ground .

Lastly does the tripod have to be set up facing in the same orientation or direction each time it is used for starsense to know where it is or do I just put it down / set it up facing anywhere when I use it.  

Edited by dmtarry

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On 30/04/2017 at 18:26, dmtarry said:

Hi all

I am new to astronomy having been bought a Celestron Evolution 6 as a 60th birthday present, I have used the scope only a couple of times via an ipad Pro and Sky Safari 5 and have ordered a Star sense unit to make alignment easier. Will I need to input location and time details or will it pick these up from the ipad? 

Can you also advise me on what the second part of this quote regarding index marks, means from the manual?

1.  Set your telescope up with an eyepiece and position the telescope in its home position or index marks . Equatorial mounts should be roughly polar aligned, but precise polar alignment is not  required . Alt-Az mounts should have the altitude aligned to its index marks with the tube level to the ground .

Lastly does the tripod have to be set up facing in the same orientation or direction each time it is used for starsense to know where it is or do I just put it down / set it up facing anywhere when I use it.  

The combination as described will take the location for those set in SkySafari. I used a SkyQ wifi unit, ipAd Pro with SkySafari and StarSense with my AVX mount for a while (until I broke the wifi device).

SkySafari supports auto align with the Star Sense over WiFi.

Be aware that this does NOT synchronise with the handset. So, if you do an alignment with the iPad you cannot expect to used the handset to slew to a target as it may not have the same skimp. Use either the HC or the iPad

For some mounts, such as my CGEM-DX, date/time and location are retained as it has a battery backup on the mount. SkySafari will not take account of that.

The setting in the mount/hand controller and within SkySafari are independently stored.

You should always start with your tripod - whatever type - pointing as closely to the north as you can. The StarSense then has a rough fixed point to start it. It will slew to several stars - takes and image and works out the co-ordinates of the centre of the image.

If you are up to 5 degrees E or W of north it will build a map.

You should do a polar alignment after the AutoAlign, then redo the AutoAlign. I doesn't take too long to do this.

If you change the orientation of the camera within the bracket you will ne to redo the StarSense calibration - otherwise it is a one of action

HTH

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If on an Alt-Az Starsense does NOT care which direction your OTA is pointing as long as the mount/tube index marks are aligned.

For best results choose a direction where clockwise rotation during alignment will move the OTA into the largest expanse of clear sky to avoid local obstructions  (like trees). I aim mine at a brick wall as it's most free of obstructions to its right.

If on a wedge; a Starsense Auto-Align DOES require your wedge/tripod to be PRIOR aligned along the N-S Meridien; with your  (wedge) latitude set and "wedge = yes".  You might physically/visually  achieve this using Polaris. See next.

Do note the due to a prevailing 'bug' the ASPA routine in Starsense on wedge does not work reliably ( but it is fine on a GEM). However, a Polar Align can be first achieved with a Nexstar + HC then reboot with a Starsense auto-align to conclude.

Also note that there is no polar align for wedge routine in SkyPortal or SkySafari.

Edited by noah4x4

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