Jump to content


Photo

Celestron VX mount

  • Please log in to reply
1053 replies to this topic

#226 bunyon

bunyon

    Gemini

  • *****
  • Posts: 3239
  • Joined: 23 Oct 2010
  • Loc: Winston-Salem, NC

Posted 28 January 2013 - 04:11 PM

Chris, I missed the graph, thanks.

Did you find that that was consistent over time? Generally, I found that with the CG5 it would be cool in Dec for a few minutes and then swing wildly off and not come back. You haven't observed that with the VX?

#227 dr.who

dr.who

    Apollo

  • *****
  • Moderators
  • Posts: 1320
  • Joined: 05 Jan 2012

Posted 28 January 2013 - 04:57 PM

Do keep in mind folks that Celestron (and others) are still dealing with the after Christmas n00b support process so they are pretty swamped. This is from a couple of people at their HQ when I drove over to deal with a problem with my C11 about 2 weeks ago. So phone's get answered first then emails. Call them if you want to talk to them ASAP.

#228 cn register 5

cn register 5

    Viking 1

  • -----
  • Posts: 760
  • Joined: 26 Dec 2012

Posted 28 January 2013 - 04:58 PM

It continued until it got cloudy or I got bored or had to pack up, over an hour in some cases.

The weather has been appalling in the UK and it's been a struggle getting any imaging time at all.

The bottom line is that this is the easiest and most successful guiding set up I've had.

Chris

#229 bunyon

bunyon

    Gemini

  • *****
  • Posts: 3239
  • Joined: 23 Oct 2010
  • Loc: Winston-Salem, NC

Posted 28 January 2013 - 05:01 PM

That's great to hear! Thanks. I never had the Dec axis on the CG5 guide for more than 10 minutes or so - and that is with polar alignment that, after the Dec guiding was switched off, allowed 2 minute exposures. Definitely wouldn't have gone an hour.

#230 EManT2200

EManT2200

    Lift Off

  • *****
  • Posts: 17
  • Joined: 22 Apr 2012
  • Loc: Maryland

Posted 28 January 2013 - 07:22 PM

Does anyone know if the AVX is designed to accept a polar scope, perhaps a CG-5 polar scope ? :question:

#231 nebultick

nebultick

    Lift Off

  • *****
  • Posts: 12
  • Joined: 09 Oct 2012

Posted 28 January 2013 - 08:14 PM

I was just wondering the same thing, I have a vixen sp polar scope would it fit. I want a goto system that will work for AP that's cheap this seems like it could fit the bill.

#232 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15562
  • Joined: 06 Jul 2007

Posted 28 January 2013 - 08:20 PM

Why mess with a polar scope when you've got AllStar?

#233 bunyon

bunyon

    Gemini

  • *****
  • Posts: 3239
  • Joined: 23 Oct 2010
  • Loc: Winston-Salem, NC

Posted 28 January 2013 - 08:46 PM

A polar scope is easier and faster. And, in my hands, as accurate. Neither preclude a drift alignment. Is it supposed to?

#234 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27511
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 28 January 2013 - 10:11 PM

A polar scope is easier and faster. And, in my hands, as accurate. Neither preclude a drift alignment. Is it supposed to?


My experience is that if you do a couple of iterations of the All Star alignment routine, you don't need to do a drift alignment. It works very well.

David

#235 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15562
  • Joined: 06 Jul 2007

Posted 29 January 2013 - 06:52 AM

A polar scope is easier and faster. And, in my hands, as accurate. Neither preclude a drift alignment. Is it supposed to?


Not my experience. My experience is that the AllStar is considerably more accurate than the polar scope--in anyone's hands. ;)

And you don't have to scrunch down and get close and personal with a polar scope.

If the VX polar scope/housing are improved from the CG5, it could be OK, but my guess is AllStar will still be more accurate and easier. ;)

#236 bunyon

bunyon

    Gemini

  • *****
  • Posts: 3239
  • Joined: 23 Oct 2010
  • Loc: Winston-Salem, NC

Posted 29 January 2013 - 07:01 AM

I suppose I should re-engage efforts to get AS to work. I tried it a number of times over the first few weeks I had the mount and while it wasn't terrible, it wasn't great. I suppose balanced against 25+ years of polar aligning an SP through a polar scope, a few weeks isn't much time.

#237 Stew57

Stew57

    Mercury-Atlas

  • *****
  • Posts: 2539
  • Joined: 03 May 2009
  • Loc: Silsbee Texas

Posted 29 January 2013 - 08:47 AM

An ASPA is only as good as your initial alignment. Don't skimp there.

#238 bunyon

bunyon

    Gemini

  • *****
  • Posts: 3239
  • Joined: 23 Oct 2010
  • Loc: Winston-Salem, NC

Posted 29 January 2013 - 08:53 AM

This is off-topic at this point, I think, but my experience was, I'd do a polar alignment with the polar scope and be very close. I'd then do an ASPA and be a little closer or a little further, depending. Either way, I inevitably had to do a drift alignment. I figure that if I can get as close with the scope, that is, for me, a couple of minutes, maybe less, then do the drift align. The only thing the ASPA did was take up some time between scope and drift.

I can get close enough with the scope alone to do 2-3 minute subs at 400mm with no drift in Dec. I only do a drift align if I image at 1200mm.

I completely agree that if one can do an ASPA and not then do a drift alignment that that would be a huge benefit. I'll spend a moonlit night soon trying to figure out where I'm going wrong with the ASPA.

Sorry for the thread hijack.

#239 ghataa

ghataa

    Viking 1

  • -----
  • Posts: 625
  • Joined: 20 Jun 2011
  • Loc: Central, NJ

Posted 29 January 2013 - 09:56 AM

The ASPA is simply awesome. Depending on where I set up on my property I don't always have a view of Polaris. With the ASPA, light pollution becomes more limiting for me than my CG5 subs.

It's worth time getting it to work!

Best,

George

#240 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5474
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 29 January 2013 - 09:58 AM

agreed. aspa is the killer feature of nexstar, along with the multiple star pointing model.

me, i don't get to see polaris at all - i'm at 1.37 degrees north latitude. so aspa is pretty much mandatory, and better than guess-timating with a compass and level, and then doing a lengthy drift align (which is what i do with my other mounts).

#241 DaveJ

DaveJ

    Surveyor 1

  • *****
  • Posts: 1719
  • Joined: 07 Jan 2005
  • Loc: NE Ohio

Posted 29 January 2013 - 10:01 AM

This is off-topic at this point, I think, but my experience was, I'd do a polar alignment with the polar scope and be very close. I'd then do an ASPA and be a little closer or a little further, depending. Either way, I inevitably had to do a drift alignment.


Unless you've also done a 2+4 star alignment before the ASPA, then the ASPA can't possibly work correctly. An initial polar alignment with your polar scope is fine, if you want to take the time & effort to do it, but it must be followed immediately with the 2+4 alignment THEN the ASPA which will get you closer to polar alignment than the polar scope.

#242 bunyon

bunyon

    Gemini

  • *****
  • Posts: 3239
  • Joined: 23 Oct 2010
  • Loc: Winston-Salem, NC

Posted 29 January 2013 - 10:26 AM

Dave that may be it. I don't do 2+4 - I just do the 2 star alignment. I'll do the full 2+4 next time out before trying ASPA. Thanks.

But my larger point is this: all that aligning and getting the computer stuff takes me far longer than sighting Polaris through the polar scope and making the necessary and trivial adjustments to go from Polaris to the pole.

#243 RTLR 12

RTLR 12

    Aurora

  • *****
  • Posts: 4558
  • Joined: 04 Dec 2008
  • Loc: The Great Pacific NorthWest

Posted 29 January 2013 - 12:03 PM

A 2 + 4 star alignment followed by an "All Star" polar alignment takes less than 10 minutes. The "All Star" take less than 10 seconds.

Stan

#244 cn register 5

cn register 5

    Viking 1

  • -----
  • Posts: 760
  • Joined: 26 Dec 2012

Posted 29 January 2013 - 03:47 PM

I'd have to demolish my house to see Polaris.

I'm not sure that a full 2+4 alignment is needed but if you do a 2* alignment use a star on the same side of the meridian as the alignment stars.

Chris

#245 DaveJ

DaveJ

    Surveyor 1

  • *****
  • Posts: 1719
  • Joined: 07 Jan 2005
  • Loc: NE Ohio

Posted 29 January 2013 - 07:05 PM

I'm not sure that a full 2+4 alignment is needed but if you do a 2* alignment use a star on the same side of the meridian as the alignment stars.


No, a 2+4 is required FIRST to give the mount the information it needs to build an accurate sky model in order to know the cone error. The cone error computed from the sky model is necessary for an accurate ASPA.

#246 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5474
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 29 January 2013 - 08:44 PM

i dont think you can even do an ASPA unless you do a 2+4... the menu option doesn't become available until enough stars have been added to the model.

#247 frozen.kryo

frozen.kryo

    Vostok 1

  • -----
  • Posts: 146
  • Joined: 28 Jan 2011
  • Loc: East of the Sun, West of the Moon

Posted 29 January 2013 - 09:16 PM

I am in a balcony type situation and my view is limited to the east.

I do an accurate 2-star alignment only, and ASPA works fine with good results as long as the star is near the celestial equator and the meridian.

#248 Ken Hutchinson

Ken Hutchinson

    Ranger 4

  • *****
  • Posts: 341
  • Joined: 24 Apr 2003

Posted 29 January 2013 - 11:55 PM

Does anyone know if the AVX is designed to accept a polar scope, perhaps a CG-5 polar scope ? :question:


I don't have one so all I can say is probably. The polar axis is hollow and the non-polar end is threaded. I take the caps off, center Polaris in the hole, and I am done. The only time I do an All Star is when I am testing for Celestron. You do not have to do a 2+4 to do a polar alignment. I never do more than 2+3 and I think you can do a polar with a 2+0 because I think the polar error is pulled from the initial two star alignment. I've never done any testing to see if the polar alignment is improved by adding calibration stars. Goto performance is, of course, but the polar alignment is based on a sync to the alignment star and I don't know if the polar alignment is affected by the general goto performance. It could be, I just don't know.

Ken

#249 cn register 5

cn register 5

    Viking 1

  • -----
  • Posts: 760
  • Joined: 26 Dec 2012

Posted 30 January 2013 - 03:26 AM

From a quick test the polar align option is available after a 2* alignment, the ASPA option is active and can be done.

At least one calib star is required to get the cone error but that's not the same as the polar align error.

After all the fork mounts only have 2* with no option of adding calibration stars and they can do ASPA.

Of course more stars should give a more accurate alignment but that's not the same as it being essential.

Chris

#250 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5474
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 30 January 2013 - 03:32 AM

thanks Chris. i will have to revisit that menu structure again..






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics