Nexstar 8 SE Help Needed Please!

[Caveman]

Last night (Sunday 6th)was the first chance i've had to try out my brand new scope, I have only had it for just a week, it's a Celestron Nexstar 8 SE purchased on 29th November from FLO.

Now while I am not new to telescopes, I am new to computerized GOTO scopes and had trouble getting the scope to GOTO with any accuracy.

I started off by leveling the tripod, entering the time date and location, then as Jupiter was on view, tried a Solar System Alignment on Jupiter, but the scope would not locate objects accurately, I also noticed that the time would not stay in the memory if it was switched off, even though the batteries were installed and a 12v power tank was used, is this normal?

Also the red-dot finder was of no use as it was fully wound to the left but still a few degrees out.

Optically the main scope seemed ok with plenty of detail on Jupiter.

Any help from fellow Nexstar owners would be SO greatly appreciated.

Cheers, Paul.

[George Jones]

Last night (Sunday 6th)was the first chance i've had to try out my brand new scope, I have only had it for just a week, it's a Celestron Nexstar 8 SE purchased on 29th November from FLO.

This a nice general-purpose (visually) scope.

Now while I am not new to telescopes, I am new to computerized GOTO scopes and had trouble getting the scope to GOTO with any accuracy.

I started off by leveling the tripod, entering the time date and location, then as Jupiter was on view, tried a Solar System Alignment on Jupiter, but the scope would not locate objects accurately

How far off was it? I find that alignments using two or three stars work better, but I have used just Jupiter on occasion.

From my observing report

http://stargazerslounge.com/observing-reports/91449-report-observing-stuff.html#post1323611

The accuracy of my alignment varies from alignment to alignment, sometimes it's dead on, and sometime it's off. If it's off, a sytematic search almost always picks up the object: tell scope computer to go to the object, search up and down for the object; tell computer to go to the object, move almost one field of view left, search up and down for the object; tell computer to go to the object, move almost one field of view right, search up and down for the object. Trick for faint fuzzies if alignment is off: have scope go to a brighter object in the same area of the sky, note where the object actually is found with respect to the computer-generated position, and use the same offset for the faint fuzzy.

I also noticed that the time would not stay in the memory if it was switched off, even though the batteries were installed and a 12v power tank was used, is this normal?

Yes.

Also the red-dot finder was of no use as it was fully wound to the left but still a few degrees out.

I have not had any problems aligning my finder.

[Cornelius Varley]

Did you enter the date in the correct format (mm/dd/yyyy) ?

What format did you use to enter your location ? Longitude / Latitude

When entering the time did you use AM/PM format or 24hr format ?

My understanding of the solar system alignment method is that you select your chosen object (planet / moon etc) then the telescopes slews to the location it believes the object to be at, then the final alignment is done by the user with the handcontrol. This is true for all goto systems, the telescope will slew to the area of the sky the alignment object is then the final adjustment is made by the operator.

The mount operates on either the internal battery pack or an external source. When the mount is powered down the date and time are lost but the longitude and latitude are retained.

[George Jones]

My understanding of the solar system alignment method is that you select your chosen object (planet / moon etc) then the telescopes slews to the location it believes the object to be at, then the final alignment is done by the user with the handcontrol.

After alignment, yes, but not for actual alignment. If I choose to use Jupiter as the alignment object, I have to slew to Jupiter by hand. Before alignment, the goto computer has no idea which way my scope is oriented.

If a careful leveling is combined with a three-star alignment using a widely spaced triangle of stars, then the goto should be very close to spot-on. Doing this without the finder working properly could be somewhat difficult.

[Caveman]

Alignment was so far off (nowhere to be seen in fact!) the object was way outside the field of a 25mm eyepiece.

Maybe I should try the 2 star alignment next time?

Yes, date entered in mm/dd/yyyy format.

So it's normal for the computer to lose it's time memory when switched off, but not the location in latitude & longitude?

I entered the time in 24hr format, and my location as London, (I live in Norwich) would this account for the error?

Should the time be entered in 24 hour format or AM & PM?

[lulu57]

I've got an 8se and I always use the two star align method. It always seems to work.

[kniclander]

re the finder problem, I had a synta scope (newtonian) where the finder shoe had not been put on straight and the finder would not point in the right direction - I was rather fobbed off by the retailer (not mentioning any names as good experiences have more than outweighed bad ones ) and I've just learned to get the object not right in the middle of the finder but a bit away from it to get it in the middle of the main scope. If you're not willing to take the shoe off and re-attach it (I wasn't cos I'm carp at anything like that) or work around it then you might need to think about asking the dealer to change it. You shoud be able to tell by eye if the shoe is on straight or not.

[BlueAstra]

The red dot finder on my 8se is right against the sideways end stop, only just in alignment.

From switch on it remembers lat, long but not time, date or daylight saving mode. Make sure they are entered in the correct format. I do a 3 star align, then goto the target. Sometimes I can't see some of the suggested stars, so i select other ones. I don't normally use the moon or planets for alignment.

[Bigwings]

Hi,

The time is lost and needs enetering every time you switch off/on.

Make sure your time is correctly formated and that it is not set to summer time (cant remeber the exact name in the time set menu.

Make sure that the time zone is to Standard Time .

I always use three star align. Being level is very important.

Its important that you center in the direction that the scope does when in goto mode. This means finding the star, press enter to select it and then use the buttons to center. I believe the default is from the right and moving up. Then press align.

I use a lighted reticule in a 12mm EP for centering.

Most often this is spot on but if difficult then I change to a 40mm EP to find and then move to higher magnification.

Hope you sort it cos ist a crackin scope

Clear Skies

Mike

[Cornelius Varley]

Alignment was so far off (nowhere to be seen in fact!) the object was way outside the field of a 25mm eyepiece.

Maybe I should try the 2 star alignment next time?

Yes, date entered in mm/dd/yyyy format.

So it's normal for the computer to lose it's time memory when switched off, but not the location in latitude & longitude?

I entered the time in 24hr format, and my location as London, (I live in Norwich) would this account for the error?

Should the time be entered in 24 hour format or AM & PM?

If you enter the time in the 24hr format am/pm doesn't matter, only if you choose to enter the time in am/pm.

As others have already mentioned the time and date are lost when you powe down the mount. These need to be inputted again next time the mount is powered up.

Norwich is about 100 miles north of London and about 1 degree higher in latitude so this might make a difference to the pointing accuracy. If you enter your postcode in MULTIMAP your latitude and longitude are shown below the map. Norwich is about 1' 17" E, 52' 38" N

Peter

[Astro_Baby]

The finder mounting shoe (the bit on the scope ) may be a bit wonky. You could try loosening one of the mounting screws and see if it can be tunred slightly. Proceeed with caution here because I dont know if these screws have captive nut on the other side or whether if loosened the nuts might just drop off inside the scope (not to be desired).

[Demonperformer]

On my 6SE, I normally do a 2-star align. If I do a solar system align, once I move on to a stellar object it often needs a bit of adjustment [probably tripod not quite level] but when I add that to the align using the 'unassigned object' option the rest of the session is no problem.

[simon e]

I just goona repeat some of the other comments.

My 8se never keeps the date and time when powered off so has to be set every time. The first thing I ever did was line up the scope dead centre, on Polaris then I adjusted the red dot right on this. The holder will adjust a bit, but you should be able to align it perfect, just a bit of trial an error

So now the finder scope is in perfect alignment with the mainscope u can align the main scope.

To align the scope I always use the two star align method. Set handunit to two star align and align the scope to Polaris from the list of known stars, dead centre the scope using the handunit. When you get Polaris in the field of view slow down the motors to about 2-3 speed and that way you can get it perfect. Then hit align.

Then I pick Vega as the next star, again from the list and move around to Vega and align on this. The manual says the further the two stars are apart the better, but Polaris and vega i find the best.

When both have aligned, do a find on Polaris or some other well known star to test. If all working it should pick up Polaris again

Then try jupiter it should pick up on it perfectly... and you should be able to see all the moons, without a problem.

Androm will be picked ok and the ring nebula, but they will look like fuzzies, well the ring in a 8se will look like a tiny ring. These can be found on the Tour list....

One word of WARNING though, watch the power cable from your Powertank, when you are slewing around fast, it tends to wrap itself around the legs of the tripod and will eventually work against your motors thus knocking out your alignment.

si

[Peter Drew]

Hello Caveman. I have a Nexstar 8SE and had a few new to me problems which have recieved good advice from SGL members.I junked the red dot finder in favour of a 9x50 optical unit, the original finder shoe was attached by screws tapped into the rear cell with no apparent captive nuts so it may well be possible to slacken them slightly to reorientate the shoe for more central collimation. I'm still concerned about accurate levelling of the tripod although it seems logical, however, "The Nexstar Users Handbook" by M. Swanson states that this is unimportant as the model of the sky that the scope generates during alignment has to be right somewhere on the Earth(?).Whatever, well worth overcoming any teething problems as the optics are great!

[Caveman]

Have managed to sort out my red-dot finder problem, the sky stayed cloud-free just long enough for me to fix it, the mounting shoe needed loosening and straightening as was suggested by other members. At least I now have a usable finderscope.

Will have another try at the SkyAlign at the weekend (weather permitting) and report back.

A big thank you to everyone for helping me. (I may still need more help!)