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sanlopez
super member
Reged: 12/03/07
Posts: 149
Loc: 36 09'46.69 N, 86 46'38.26 W
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I don't think I was wrong; he asked of he needed to enter location BEFORE alignment, and yes, you need to do that, by either doing it manually or by selecting a nearby city.
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Celestron GPS C925
Celestron Nexstar 5
2005 Gretsch SSLVO
Fender Custom Vibrolux
1963 Galaxie 500 XL convertible
1973 VW type 181 "The Thing"
And an absolutely wonderful wife
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coutleef
scholastic sledgehammer
Reged: 02/21/08
Posts: 827
Loc: Montreal and St-Donat, Québec,...
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Still no answer to my question above!!!
I think you will be off by 15° but i am waiting for Bob or Tel's blessing on that answer.
Franocis
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François
Nexstar 8 SE
50mm StellarVue finderscope, Astronomik UHC-E and Orion OIII filters
WO Swan 40mm; TV Pan 22mm; TV Nagler 9T6, 12T4, 17T4; TV Plossl 11mm and 15mm.
WO 2" dielectric diagonal retrofitted with Denk Power Switch (and now reach the zenith with the shorty adapter).
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Tel
Carpal Tunnel
Reged: 03/31/06
Posts: 2632
Loc: Wallingford England
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Hi Francois,
Sorry to be late in trying to answer your post, but I have to admit that I also find "time and stellar positioning" somewhat bewildering.
However, perhaps this is a basis for an explanation.
Take my location, which, to all intents and purposes is on the zero longitude meridian: hence Universal Time and thus, as you may well know, UT prevails here for 6 months of the year until H.M.'s Government, in its wisdom, decrees that we shift our UK time one hour forward between March and October to British Summer Time or as you probably call it, Daylight saving Time.
This however, does not change the position of the stars; only the relative time we mortals look upon them. Time settings on earth therefore, are a mere convenience to ourselves to help us run our daily lives.
So, to try to answer the question (and please correct me someone if I get it wrong): whether summer or winter, I personally choose to use UT throughout the year.
This means that at the present time, (BST or DST), when I go out to view at say 10:00 pm, I programme the 'scope to 9:00pm. on any certain date. (For further reference, let's call that date today: 08/26/08).
Now let's say I terminate my session at 11:30pm tonight and switch off the 'scope but want to resume viewing at 12:30am according to my watch which is set for earthly convenience to BST / DST. When I do resume therefore, it will the 08/27/08.
But, as I like to use UT, I would then set to 11:30pm and (still) 08/26/08. In doing so and looking up, I note that the stars however have remained in the same position with no geometric offset irrespective of my fabricated time shift.
Making my alignment therefore, the 'scope, as usual, recognises my two stars (e.g. Altair and Polaris ) and builds its picture of their relative positions accordingly.
As I said, I like to use UT but that's not just because I have it on my doorstep. I know that RandyR, who used to moderate this forum, also employs UT, and he lives in Colorado.
I hope this explains it as far as my interpretation goes, but, I may well be wrong, in which case, someone PLEASE come to my rescue too as I really do have a problem getting my head around celestial mechanics !
Best Regards,
Tel
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Truth is the cubed root of Verbosity.
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Tel
Carpal Tunnel
Reged: 03/31/06
Posts: 2632
Loc: Wallingford England
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Quote:
Try doing a "solar system align" and align to Jupiter. It should be easily visible in the South/Southeast sky in the early evening for you now (brightest object in the S/SE). This is a single point align, and you should get a successful align with it. You should be able to "goto" targets near Jupiter pretty successfully if you can align to Jupiter.
Let us know!
With all respect and while I perhaps see a motive here in getting Arbi up and running, I don't think a simple solar system align gets near to the route cause of the problem because inevitably and soon, a more accurate alignment will be required for which in turn, accurate HC settings will be necessary.
Is it then not better to bite the bullet early and begin at the bottom of the learning curve rather than in the middle ?
Purely this one guy's opinion. The ultimate choice must of course, rest with Arbi.
Best Regards,
Tel
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Truth is the cubed root of Verbosity.
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coutleef
scholastic sledgehammer
Reged: 02/21/08
Posts: 827
Loc: Montreal and St-Donat, Québec,...
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Oups, sorry Tel,
the question i was referring to is embedded in the thread and is not the original question.
We were wondering, if you make an error when you introduce the date (for whatever reason) corresponding to a one day difference when aligning, would your target be off by 1° or by 15°??
During the day, targets move by 15° per hour so to speak (360° in 24 hours). I tougth there could be a 15° difference.
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François
Nexstar 8 SE
50mm StellarVue finderscope, Astronomik UHC-E and Orion OIII filters
WO Swan 40mm; TV Pan 22mm; TV Nagler 9T6, 12T4, 17T4; TV Plossl 11mm and 15mm.
WO 2" dielectric diagonal retrofitted with Denk Power Switch (and now reach the zenith with the shorty adapter).
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rbdynamics
member
Reged: 08/18/08
Posts: 12
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OKAY GUYS here it is!!!
I did the Staralign and it was SUCCESSFUL!!!!
The problem was the finderscope, it wasn't centered so I removed it and screwed it back on, adjusted it and it worked out.
Now, I messed around with the tour button but most of the things that I am sent to are hardly seen (probably due to light and clarity).
Unfortunately, the data cable that came with my unit doesn't work with my laptop (seems as if its really outdated) and for that I would have to purchase one that has a USB instead of the port.
Under planets I have options like Pluto and other planets but obviously since I'm really far away, I can't be able to see it!!
So, my next step would be to purchase accessories. What do you guys reccommend? I am really considering an eyepiece, I know that some of you guys mentioned upgrading the eyepiece.
Again, if it weren't for you guys, I would still be having lots of problems w/ my scope. Thanks so much guys!!!
Arbi
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barnowl
member
Reged: 01/04/08
Posts: 36
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While waiting for Tel to give the definitive answer, it seems to me that: If I enter a date that is six months off, the stars will be 180 degrees out of position from where the go-to system thinks. Therefore, if I enter a date that is one day off, the stars will be one degree out of position.
Lee
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Bob Griffiths
Post Laureate
Reged: 10/10/05
Posts: 4205
Loc: Frederick Maryland
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Arbi:
When using my 8i or any other Goto Scope I only need 4 things to actually observe..
1. Power Source...
2. Small flashlight (red lens)
3. A "Good" adjustable chair....with a back ...(IF I intend to observe for more then 10 minutes.)..
4. At least one eyepiece
Besides those. I really do not need much ..I like to place my EP case on a small stool or table like a folding canvas camping stool/table ..cheap and keeps it off the ground and saves my back
A decent Barlow and an additional EP or two will go along way to giving you different views...I am assuming the scope came with a 25 mm EP and has a FL of 1500...
25 mm OEM EP = 60x and with the barlow 120x
40 mm EP = 37x and 72x with the barlow
15mm EP = 100x and 200x with a barlow
Since MOST of "my" viewing ...no matter what scope I am using is between 40x and 200x I'd look for a couple of CHEAPER eyepieces that you know darn well will be replaced in a year at most...AFTER you finally figure out what magnifications you really need you can start researching what specific type and brand of EP to buy...
The Barlow however should not be a Cheapie....but it does not need to an expensive one either ..you can use it forever so I do not think of Barlows as disposables...
Bob G
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CPC1100
Nexstar 8i + GPS & Rays Brackets
Denk S1 power switch
Orion 100 mm Refractor
Meade LXD 55 ...AR-5 127 mm Refractor
Exploradome Observatory S.I.E. (Smiling Irish Eyes)
39*21'03" N
77*28'12" W
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Bob Griffiths
Post Laureate
Reged: 10/10/05
Posts: 4205
Loc: Frederick Maryland
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Francios::
To be honest I have been thinking about your question for over an hour and I'm just confusing myself the more thought I put into answering it....BUT let me say that I am now a little more thankful that my GPS enters the darn time and date...so I will no longer complain that they are way overpriced for what the do..when using a SkyAlign equipped scope...
Missing the day by 24 hours should really screw up the works..
IF you somehow managed to get an alignment successful message I would be surprised...The stars are NOT exactly in the same location at 10 PM tonight as they were last night nor will they at the same place tomorrow night...
BUT My guess is that your goto's will be off by 1 degree and I based that answer on Lees' (Barnowl) note about 6 months from now...
Now I bet I'll be tossing this question around in my head for hours if not days....LOL
BTW...Like Tel and others I do not mess with Daylight Savings time etc...I run Eastern Standard time (UT - 5 hours) 365 nights a year BUT I do not tell the GPS that...it downloads the UT then adjusts for my offset and I just accept its answer...
Bob G.
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CPC1100
Nexstar 8i + GPS & Rays Brackets
Denk S1 power switch
Orion 100 mm Refractor
Meade LXD 55 ...AR-5 127 mm Refractor
Exploradome Observatory S.I.E. (Smiling Irish Eyes)
39*21'03" N
77*28'12" W
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Tel
Carpal Tunnel
Reged: 03/31/06
Posts: 2632
Loc: Wallingford England
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Quote:
While waiting for Tel to give the definitive answer, it seems to me that: If I enter a date that is six months off, the stars will be 180 degrees out of position from where the go-to system thinks. Therefore, if I enter a date that is one day off, the stars will be one degree out of position.
Lee
Hi Lee,
Well I don't know about the definitive answer, but my belief is that you are right. However there are two issues here as I see it.
In the first place, as far as my understanding goes, there is a four minute shift from one day to the next, easily measured for example, each time a fixed non-circumpolar star rises. In angular terms that means, as you have pointed out, a fixed star shift of one degree every 24 hrs (or more correctly every 23h.56m).
Secondly, there is of course, the very apparent motion of the background of fixed stars due to the earth's spin which amounts to the 15 degs./h previously mentioned.
I hope this is basically correct but any further comments would be most welcome.
Best regards,
Tel
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Truth is the cubed root of Verbosity.
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atnbirdie
member
Reged: 12/10/06
Posts: 67
Loc: Middletown, MD
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I did a quick test using Cartes du Ciel. Picked a target star and noted Alt/Az position. Advanced date by one day and noted Alt/Az position of same target. Az had changed 20' and Alt by 19'.
Steve
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Orionis Observatory
CPC1100 XLT; NexStar 8SE
-Denkmeier S-1 Shorty Power Switch
-Lumicon Filter Slide
-Starizona Feathertouch Microfocuser
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coutleef
scholastic sledgehammer
Reged: 02/21/08
Posts: 827
Loc: Montreal and St-Donat, Québec,...
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Thanks for your answers,
i had done a three star alignment this winter or spring putting the wrong date (by a day or two) and the alignement was successful. But coming back at the stars chosen for the alignment to see if they were the right ones, i had answers that were just not possible, i know my sky.
That is when i started using the Auto two star align after seeking your advice. That was day one of 'having always successful alignments'.
One fellow here on CN had replied at that time that if i input the wrong date by a day, i would be off by 15°. Never gave it a thougth before this thread. Thanks to atnbirdie for the effort he has put in it.
15° per day was too much. Looking at monthly sky maps we are one hour earlier every 15 days (1 hour is 15° movement in a night, so 15 degrees per 15 days makes the 1 degree change, similarly to 360° in 365 days). The calculations by atnbirdie are more precise.
We always learn, don't we, at least me!!
Thanks, very instructive
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François
Nexstar 8 SE
50mm StellarVue finderscope, Astronomik UHC-E and Orion OIII filters
WO Swan 40mm; TV Pan 22mm; TV Nagler 9T6, 12T4, 17T4; TV Plossl 11mm and 15mm.
WO 2" dielectric diagonal retrofitted with Denk Power Switch (and now reach the zenith with the shorty adapter).
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MachMike
member
Reged: 12/08/07
Posts: 79
Loc: Colorado
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I posted a reply on the CPC forum as well for you. Use external power.
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Nexstar CPC 800 XLT
OPT 2" 99% dielectric diagonal
Tele Vue 24mm Pan, 13mmN6, 9mmN6, 13mm ETHOS
Celestron 2x Ultima Barlow
1000 Oaks LP-2, and O-III Filters
Feather-Touch Focuser
20/10 eyesight
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