The SkyX/T-Point, why buy?

[Herrman]

Hi,

I've been reading with interest Nick Szymanek's articles on creating pointing models using The SkyX and T-Point, which have been spread across recent editions of Astronomy Now. While reading it seemed to me that the methods and outcomes are strikingly similar to those experienced when working with Cartes Du Ciel and EQMOD. While both these programs are free to download, the combined SkyX/T-Point package will set you back somewhere around $580, so I can't help but wonder, what does the Sky package offer that Cartes/EQMOD lacks? Greater pointing accuracy? Use with mounts other than the non-EQ family?

If anyone has any answers or thoughts on this, I'd be very interested to hear them.

I'm not itching to rush out to invest in The Sky; just curious.

All the best, Herrman

[andrew s]

I have been a The Sky user since The Sky 4 and have been through 5, 6 and now X. I can't comment on the software you mention as I have never used it. 

When I got The Sky 4 there was no free software available. I did use The Sky with non Software Bisque Mounts  but now I have an old style Paramount which came with the Sky 6. I upgraded to The Sky X to remain current but its integration (with the Camera, T Point and Data base add-ons) allows for fully automated operation and if you are doing standard imaging you can construct scripts etc. without programming.

I do slit spectroscopy and this requires centering a star on the slit (50 - 200 microns wide) when the slit is not a the center of the field of view. To do this I had to construct a script which required some programming but I could take spectra in an unattended way. I needed the database add-on as I have a very small field of view (10x10 arc mins) and to reliably plate solve you need one enormous amount of catalogue stars!

For automated operation The Sky X is hard to better but as you say it does cost. For me it enabled me to do spectroscopy I could not have done simply any other way.

Regards Andrew

[Herrman]

Hi Andrew,

Many thanks for your reply, most interesting.

I see you've used The Sky with non-Bisque mounts; did you experience any connection problems? If, by chance it was an EQ mount you used, did you connect straight to the mount, or via the Synscan? The reason I ask, is that since my initial post, I've started to (again) have problems with the EQDIR adapter not being recognised by my laptop. I'll post a request for help on SGL, and suspect I'll receive some valuable help with overcoming the problem. However, I'm beginning to get slightly frustrated with intermittent  EQDIR driver issues, so I'm now looking more than causally at The SkyX package and add-ons.

Also, if I understand what you say about the demands of spectroscopy, SkyX can achieve very high pointing accuracy and precision. With EQMOD/Cartes DU Ciel, I've found selected targets generally don't end up centrally in the field of view- although I quite freely accept this could result from operator error. A more precise Go-To system would certainly be of benefit when imaging.

Thanks again, Herrman

[andrew s]

Herman, sorry I can't help with the EQ mount. I used The Sky with a Fullerscopes Mk IV mount and AWR drive system and then a Parallax mount which used the AstroPhysics drive system. I never had any issues with the software driving them. Hardware comparability (especially USB to Serial) can be an issue but I have had no problems as long as I use genuine USB to Serial converters.

With the Paramount and my home made Telescope I get about 10 arc second pointing using a 300 point T-Point model. This is not good enough to center the star on the slit but by plate solving and then jogging the mount (all in a script) I get the required accuracy. The Sky can do this automatically with a closed loop slew if the object needs to be centered but my slit is just off center.

Sorry I can't be more help.

Regards Andrew

[chrisshillito]

Hi Andrew,

Many thanks for your reply, most interesting.

I see you've used The Sky with non-Bisque mounts; did you experience any connection problems? If, by chance it was an EQ mount you used, did you connect straight to the mount, or via the Synscan? The reason I ask, is that since my initial post, I've started to (again) have problems with the EQDIR adapter not being recognised by my laptop. I'll post a request for help on SGL, and suspect I'll receive some valuable help with overcoming the problem. However, I'm beginning to get slightly frustrated with intermittent  EQDIR driver issues, so I'm now looking more than causally at The SkyX package and add-ons.

Also, if I understand what you say about the demands of spectroscopy, SkyX can achieve very high pointing accuracy and precision. With EQMOD/Cartes DU Ciel, I've found selected targets generally don't end up centrally in the field of view- although I quite freely accept this could result from operator error. A more precise Go-To system would certainly be of benefit when imaging.

Thanks again, Herrman

Not sure I can see how TheSkyX help with your EQDIR problems? TheSkyX still needs and interface to talk to your mount and that is most likely going to be via ASCOM/EQMOD/EQDIR.

To be honest when it comes to imaging many folks have moved away from relying solely on a pointing model approach and instead uses an iterative "platesolve and goto" method - astrotortilla has been the game changer in this.  Whilst pointing models can certainly achieve accurate gotos their performance is ultimately dependent on the quality of the data they are given,  by the quality of the equipment being used, and most significantly, by the assumption that absolutely nothing has changed since the model was created.

I'm sure TheSkyX is a fine piece of software and worth its price to those who use it. However software alone doesn't guarantee better astronomy and it could be that the problems you currently experience will continue to apply no matter what software you use.

Chris.

[michael8554]

Agree with Chris.

Bit of a no-win situation really

If your GoTo's aren't accurate enough you end up using PlateSolve2 or Astrotortilla to find where you are

Or you buy TheSky and T-Point and it still isn't accurate enough, so you use PlateSolve or Astrotortilla to find where you are.........

Michael

[Herrman]

Many thanks Andrew,

It's interesting to learn that USB to Serial, without additional interface, has worked with your mounts. Like you, I had problems with USB to Serial converters, but my current (genuine) one, that I've had for a few years now, has proved reliable.

Plate Solving is something I must get to grips with, I downloaded Astrotortilla ages ago, but done nothing with it- when clear skies and free time coincide I feel more inclined to get cracking with imaging, than experiment with plate solving. Perhaps a run of clear skies over the Christmas break (we can but hope!), will entice me to do so!

Thanks again, Herrman.

[PNJ]

Hi

I use EQ mod, but without the eqdir.  I connect direct to my AZ EQ6 Gt handset then set it to PC direct, works fine.  I also have Sky X,  without T point. What I find it good for is image link.

Having done a goto to a target, I normally take a short exposure then image link with Sky X , it then does a plate solve in seconds.  Then I Sync .  I totally portable each night having to set up every time,  so if I'm on a imaging run the 2nd night, I just load in a image I took the night before, use image link, and Sky x fine slews to centre the target.  and again syncs.

very useful.   so I'm using EQ Mod with Sky X

Paul J

[Herrman]

Hi Chris,

Many thanks for your response.

As I mentioned above my initial post, interest in TheSky X was stimulated by the Astronomy Now article. The pointing model process described appeared so similar to EQMOD, it made me wonder, why pay for TheSky when EQMOD is available for free.

A couple of days after posting this question I had another bout of problems with the EQDIR drivers for my HiTech Astro module, I eventually solved this by reverting to an older Ian King sourced module. I'm still puzzling over this; I faithfully followed Hi Tech's instructions on driver download (something I've done several times before), but laptop, drivers, and module refused to communicate, however the old module worked straight away when plugged in. It was this problem that got me thinking about alternative forms of mount control that avoid EQDIR interface. Although I see from your reply, EQDIR would likely still be needed.

Both your comments, and those posted by Andrew make me realise that I must dedicate some time to understand and use plate solving, but I'm sure it will be worth the effort in the long run.

Something I would be interested to fathom is why the following occurs: if when building a pointing model using EQMOD, I centre and sync on 'star a', follow this by Go-To 'star b', then centre and sync, if I then Go-To back to 'star-a', the star is invariably not returned to the centre of the field of view (thinking about one of the points you mention above, I would have thought very little would change during this phase of model creation and use). Does with happen because of, operator, software, or mechanical limitations? The mount in question is an EQ8 and there have been mutterings that these are prone to backlash problems (I hear a collective SGL groan- oh no, he's gone and mentioned EQ8 and backlash!), so although overall I've been please with my mount's performance, I wondered if it's hardware, not software responsible that's responsible for this.

Just to conclude, I think EQMOD is marvellous, and I'm grateful to those who've worked so hard to create and maintain it, that's why I wondered why pay for SkyX, or more specifically T-Point, unless it can produce an appreciably more precise model? Historically, for me it's been just the interface module and drivers that have at times been the source of frustration.

Certainly, this correspondence has encouraged me to tackle plate solving.

Thanks again, Herrman