Newbie Introduction Hi & First Light

Meadehead · #1 04-10-2007, 01:17 PM

Hi Everyone,

I'm new to astronomy and have always had a passion and interest about what's up there for as long as I could remember.
I have been reading magazines and drooling for years about buying my own telescope but with work & family commitments have never made the almighty plunge until my wife asked what I would like for my 43rd birthday

....... So I did some reaserch for a compact/portable GoTo telescope and purchased a Meade ETX-125PE from Bintel in Melbourne and had my first light last week. I was blown away with the moon & Jupiter as were my wife & kids and hopefully this will get them into it.

One problem I have is the GoTo function is off by 5-10 degrees to the right and after speaking to Bintel & trying an advanced alignment and the helpful staff determined my ETX-125PE had a faulty RA motor and offered to repair, replace or upgrade, and guess what I did? I'm afraid "Aperture Fever" had set in so I am waiting for my Meade LX-90GPS 8" to arrive next week

..can't wait! I'm glad I purchased from a reputable retailer, and hope I made a good choice.

Anyway I don't want to blab too much, just want to say hi

looks like a friendly forum and will be posting lots of questions.

manny · #2 04-10-2007, 01:46 PM

Welcome Meadehead
Enjoy your new scope and yes Bintel are a very good company to deal with and will always try to resolve any problems you may have with equipment.

Best wishes
Manny

rmcpb (Rob) · #3 04-10-2007, 03:28 PM

Welcome to IIS John

Great to hear a good story about suppliers. Too often we throw brick bats and never offer the bouquets for good service. Sorry to hear about your terminal aperture fever, if you jumped from 5-8" in that time what will you be spending your money on in a years time???????????

Keep looking up.

ballaratdragons (Ken) · #4 04-10-2007, 04:55 PM

Does that mean that if the LX-90GPS 8" is faulty, you are going to take it back and get a 12"RC?

Meadehead · #5 04-10-2007, 06:43 PM

Quote:

Originally Posted by ballaratdragons

Does that mean that if the LX-90GPS 8" is faulty, you are going to take it back and get a 12"RC?

Ha Ha.

I don't think I'll be spending any more for some time as I've blown my budget for the next couple of years, and not only that, I would have to change my signiature again!

Ric · #6 04-10-2007, 11:49 PM

Hi John and welcome to the group, you'll have a great time here.
Congrats on your second new scope, I'm sure you will get a lot of pleasure from it.

The Bintel people certainly are a great bunch, I have always had great dealings with them and can't fault them.

Cheers

jakob · #7 05-10-2007, 10:19 AM

Quote:

Originally Posted by Meadehead

Hi Everyone,

One problem I have is the GoTo function is off by 5-10 degrees to the right and after speaking to Bintel & trying an advanced alignment and the helpful staff determined my ETX-125PE had a faulty RA motor and offered to repair, replace or upgrade, and guess what I did? I'm afraid "Aperture Fever" had set in so I am waiting for my Meade LX-90GPS 8" to arrive next week

..can't wait! I'm glad I purchased from a reputable retailer, and hope I made a good choice.

Anyway I don't want to blab too much, just want to say hi

looks like a friendly forum and will be posting lots of questions.

Wellcome to Icinspace.
I had similar proplems with my ETX but I did a re-calibration of the sensor.
My reasoning was that the magnetic north is 12 deg off and a calibration on sigma Octance elimitated this.
My scope works fine now and points to the alignement stars within a few degrees. (Don't mention aperture fewer, I just bought a 16" Lightbridge!)

citivolus (Ric) · #8 05-10-2007, 10:25 AM

The 8" LX90 is a great starter scope, big enough to bring in a decent amount of light, small enough to grab and go, and easy enough to use to not be intimidating. Welcome & enjoy your scope!

You say you've blown your budget - wait until you discover accessories!!!

Eric

bizarro (Greg) · #9 05-10-2007, 11:22 AM

Hi John,

You wont regret the upgrade to the LX90. I'm very pleased with mine.

A couple of points worth noting when you start using it which will make life a little less frustrating for you.

It does suffer from some "rubber banding" as users call it out of the box, especially if you try to resync on an object. What you'll find is the scope has a tendency to drift off the object after you centre it. Follow the drive training procedure (which can be done during daylight on a terrestrial object) and that will take care of that problem. This is something you will have to do from time to time.

As Jakob said I also found the auto alignment didn't work, most likely due to the LNT module not knowing our true north / mag north offset. I manually level the tripod with a spirit level, point the scope to true north, and then perform a two star alignment. Works fine. The LNT module can be calibrated by following the calibrate sensors routine which involves pointing the telescope at Sigma Octans (not Polaris as the manual says). I haven't been to a dark enough site yet where I can see that star so I'm still working on that problem. To be honest the two star alignment is quicker than auto align as it takes some time to level itself and find north so even if the auto alignment worked I'd still do the two star alignment.

There are a few of us LX90 users about so any questions ask away and I'm sure one of us will be able help.

Cheers,
Greg

Meadehead · #10 05-10-2007, 01:56 PM

Thanks for your kind words and advice. Greg, I really want to utilise the Automatic alignment but if you're having trouble finding Sigma Octans I have a feeling I'll have some trouble as I have just done a Google search and found it but not in my star map - How did you find it Jakob? I suppose I'll have to do the two star alignment for now but do I need to use a bubble level or any spirit level?

bizarro (Greg) · #11 05-10-2007, 04:33 PM

John,

You still have to align to two stars with the auto align so all the two star alignment is eliminating is the leveling and finding north. The auto align does automatically pick bright stars though rather than you selecting which stars you want to align to. The theory with auto align picking bright stars is that it should be pretty obvious which one it's trying to align to. The problem with the sensor being off is that it is so far off the star that when you slew to it (and repeat it a second time) it assumes you've made a mistake and picked the wrong star because it's further off than it thinks it should be.

Sigma Octans is rather dim (something like mag 6.5) which is too dim for me to see from my backyard in the middle of Sydney. That's the main reason why I haven't done it. I have had the telescope at darker sites but I'm so eager to get going and make the most of my night I completely forget about calibrating the sensor.

Most basic star maps only show the three brighter stars in Octans which is why you're struggling to find it. Sigma Octans is in Autostar so if you find auto align doesn't work do a two star align and tell it to go to star SAO 258857 (shows up as Polaris Australis I think). Then you can see where it is and have a go at the calibration process.

Don't be scared of the two star alignment. Leveling the mount with a spirit level is something you should do anyway. To find true north just point the scope 12 degrees west of magnetic north. Have a copy of the monthly sky map from skymaps.com and you'll have no trouble identifying bright stars to align to.

Cheers,
Greg

jakob · #12 05-10-2007, 04:42 PM

Quote:

Originally Posted by Meadehead

Thanks for your kind words and advice. Greg, I really want to utilise the Automatic alignment but if you're having trouble finding Sigma Octans I have a feeling I'll have some trouble as I have just done a Google search and found it but not in my star map - How did you find it Jakob? I suppose I'll have to do the two star alignment for now but do I need to use a bubble level or any spirit level?

It took me some trouble to find, but here is what I did:
Enered the position of Sigma Octans as a user object in Autostar.

Right Ascension (hours): 21.1462
Declination (degrees): -88.9564

Set up and aligned Scope, called up Alfa Crux, re-syncronised on alfa Crux just to minimise any error.
Then selected U ser object Sigma Octans.
Then I had a good look around the Area (I sketched position of neatby stars).
Then I read the setting circles on the scope.
Now without moving the tripod I followed the Instruction to calibrate the sensor.
At the end, when requested to point to Sigma octans, I moved the scope (using the controller) as good as I could to the position I had marked before and confirmed the nearby stars I noted before and comleted the Calibration.

I think with a low power EP you should be able to to this even in light polluted area (I had the lights of Sydney to contend with).

Good luck!

Meadehead · #13 08-10-2007, 10:58 AM

Thanks Guys & great explanations, the procedure makes sense now which I can understand and follow. I just have a couple more questions:

I actually have performed a two star aligment previously so this part should be easy but I'm not familiar with how exactly to re-synchronise. Is there a re-synchronise option via the setup menu?

To find magnetic north I suppose I would have to buy a compass first (any type in particular), then to move 12 degrees west would the setting dial markings on the scope give me an indication in degrees?

bizarro (Greg) · #14 08-10-2007, 12:40 PM

John,

Resynchronising improves the precision of the tracking. At the end of the day the alignment we do, be it auto, two star etc. is still rough. Good enough for viewing objects for a while but things wont appear dead centre in the eyepiece or track perfectly for hours. When precision is required, centre on the object that you've just slewed to, press and hold enter for two seconds and then press enter again. This tells the telescope that you're now centred on the object and this will now improve the precision for the part of the sky that you're now looking at.

To align the scope to true north I bought a cheap orientering compass which has a dial you can turn. I turn the dial 12 degrees to the west and then I can line up the needle in the parallel bars. I put it up against the flat edge at the rear of the tube (where the eyepieces connect to) and rotate the scope until the compass needle lines up. The dial on the base of the scope wont help you as that's for determining Right Ascention (RA) which is measured in hours, minutes and seconds.

Cheers,
Greg

Meadehead · #15 08-10-2007, 04:17 PM

Greg,

I think I found an explanation the manual, they call it the "ENTER to Sync Feature" as a tip. Thanks for this Greg I never would have understood it as you have explained it.

High Precision:

If High Precision is turned on, when looking for a faint celestial object ( i.e., a nebula or galaxy), AutoStar first slews to a nearby bright star and displays "ENTER to Sync." Center the star in the eyepiece, then press ENTER. At that point the telescope has a high precision alignment to that part of the sky and it then slews to the object that was originally requested.

Tip:

If the "ENTER to Sync" feature is accessed by mistake (holding the ENTER key for more than 2 seconds), press MODE to return to the previous screen.

bizarro (Greg) · #16 08-10-2007, 04:57 PM

No worries John. Look forward to hearing about your observations when you get the scope.

If the weather clears here in Sydney next weekend I'll probably head off to a dark site so if I do I'll have a go at calibrating the sensor. Will let you know how it goes.

Cheers,
Greg

Meadehead · #17 08-10-2007, 05:51 PM

Thanks again guys, I'll let you know how I go.

Meadehead · #18 11-10-2007, 05:19 PM

Guys,

I've just exchanged my etx and picked up my new LX90GPS 8"

It's in my car boot waiting for me to close up shop & get home and un-pack it and have a play tonight........ I can't wait!

The weather isn't good so I'll only be looking at it, not through it

but will provide a first light report as I'm eager to see the diference between a 5" and 8".

rmcpb (Rob) · #19 11-10-2007, 06:15 PM

No comparison!!

Meadehead · #20 15-10-2007, 10:59 AM

Hi everyone,
I had my first light yesterday and I'm very happy with it's performance. Auto Align worked great the first time and I'm impressed with the go to accuracy as objects were dead-on centre. I saw 47 Tuc and it was amazing!

One thing though, with a 26mm eyepiece when I adjust the focus knob the image shifts to the left when focussing in & then to the right when focussing out (Or vice-versa) approx 30% of field of view, then I would have to re-centre . As this did not happen with the ETX could it be a fault?
I'm thinking when I adjust focus this should traverse the mirror evenly but instead it could be twisting causing the image to shift but I 'm only guessing as I have never seen how this mechanism works.

Regards,
John M