Aligning problems

[strummer4]

Hi. I have recently acquired a Meade Lx 90 8" acf. I could use some help in figuring out how to align it properly. It's a second hand one so do I need to put in my new lat. and long. Or should the GPS automatically do that? Do I need to reset it? Which is best..to point to true north or magnetic north? I tried aligning it last night but it said it was slowing to alpha centauri but ended up in Scorpio! So I figure I must be doing something wrong! I've read the manual, but need some suggestions on what to try....
Thanks
Strummer:rolleyes:

[brisen]

Steve

I live just down the highway from where you are and align to the South as we need to align to the south celestial pole (rather than the North). I have found a land mark which is south of where I set up and point the centre of the mount at this. Not sure about the GPS and setting the latitude on the scope you have, but with the Celestron I have you have to adjust to the latitude.

Brian

[strummer4]

Oh ok thanks Brian. That makes sense. I'll try that...
It doesn't seem to be an option on the Meade. It just asks if I want to point to true north or magnetic north....doesn't mention anything about south.
The guy I bought it from demonstrated it for me and he had it pointing to north...anyway I'll try again...I'm confused !
All the best
Steve:screwy:

[Draco]

Hi Steve

I also recently got an LX90 and can relate to your issue. I used the alignment process that meades go through once you turn them on. The GPS can get a fix on your location but I think you still need to show it the direction it is pointing. Also, during my sky night at Linden, I got told a very important tip. Ideally you need 3 stars to align your scope (Celestron does this) however Meades only use 2 and then calculate based on this. It is absolutely imperative that your Meade is level when you do the alignment.

So here are the steps you could use
1. Turn your telescope on (or press 0)
2. You can skip the GPS fix by pressing any key
3. Use a level to ensure your telescope is level to the ground (check north-south and east-west).
4. Use the level to ensure the tube is horizontal.
5. Use the compass (or your smartphone compass) to locate North. Ensure your tube is pointing to it
6. Your setup will be asking you to point the tube to North and press 1. for true north or 2 for magnetic. I was told to select true North (need to get back on why tho :( )
7. then use easy align. It will give you stars and if you can see them then select them and your scope will go locate it. If it is not centered in the eyepiece then use the arrow keys on the keypad to align. To ensure the star is in the center, you can use the focuser to defocus. The big circle around the star should now be easy to center.
8. Once you have gone through 2 stars for alignment, your scope will be aligned properly.

You can test by going to a star and you should be very close to it (might not be exact).

Hope this helps
Niv

[strummer4]

Ok thanks heaps . I'll try that and let you know how it goes.
:) also wondering what eyepieces to get (it only came with the one) and whether a x2 Barlow is a good option. Also thinking about a dewlap and wondered. What I need in the way of an adapter to take a camera, and also what you could recommend for a good beginners astro camera? Sorry for all the questions, I know I'm a pain, but appreciate your help.
Steve:D

[Jon]

AFAIK, the Meades need youn to point North if you are doing an Alt/Az align.

They also have a polar mode, for use with a wedge (you will need a wedge and to work in polar mode if you want to do astrophotography). In polar mode, you have to align with the South Celestial Pole.

Just make sure in the setup menu that the scope is set up in Alt/Az mode. That could easily explain why it's shot off to Scorpio not Alpha Centa



EPs - what one to get depends on what one you have already! I'd suggest you try to end up with one around 25mm and one around 12mm for starters (or get a 2x Barlow instead of the 12mm EP).

Dew is an issue with the corrector plates on SCTs. I've got a dew heater which is great but I believe the DIY dew shields that you'll find plenty of posts about here work well.

Regarding cameras - I wouldn't charge out and spend your money before getting a bit of advice and experience. If you can lay tour hands on a DSLR of any kind, you can get some quite good photos by just attaching the camera body to the telescope with one of these (http://www.bintel.com.au/Astrophotography/Camera-Adapters---T-Rings/Bintel-Camera-Adapter-1-25-/1302/productview.aspx) adapters plus one of these (http://www.bintel.com.au/Astrophotography/Camera-Adapters---T-Rings/Canon-EOS-T-Ring/36/productview.aspx) T-rings (that one's for Canon but they come for all makes). You will be limited to about 30s exposures with your alt/az mount.

If that's all working for you then you will want to look at getting a wedge (http://www.bintel.com.au/Mounts---Tripods/Wedges/Meade-Equatorial-Wedge-LX-90/118/productview.aspx), getting your polar alignment really good, then entering the dark world of autoguiding. That's the crucial jump that allows you to take exposures of 3-10 minutes.

Only once you have all that under control will you want to start investing in a dedicated astronomical camera.

[Draco]

Hey Steve

Yup pretty much all that Jonathan said is on the dot. I have a 26mm plossal eyepiece that came with the scope and a 10mm.

Just keep in mind the higher magnification you go, the more dimmer the object will get and without excellant seeing (this is what we astro buffs call the ability to see clearly.. so bad seeing means lots of dew in the air, clouds etc) .. you wont get much from high mags. For eyepieces, the field of view is quite important. When you look at the sky using your finderscope, you see a small part of it, but when you see through your telescope, this section is magnified so many times so basically you are seeing a smaller portion of that sky. FOV is how much of that sky you can see, measured in arc minutes or degrees. I love large field of views though they are expensive. Also eye relief is quite important.. this is how far you have to be from the eyepiece to be able to see the image .. if you are wearing glasses then it is better to have a longer eyerelief.

Are you part of a astro club? they will def give you much more tips. also get some sky charts or apps on your phone. I use sky safari

Regards
Niv

[Camelopardalis]

Which eyepieces are useful depends on what you want to look at :)

For wide field views/large objects you might want a low power eyepiece. Also consider that eyepieces are available with greater apparent field of view which not only alters the viewing experience by being more immersive, but they'll also show you more of the sky for a given focal length (and empty your wallet faster :D )

Again depending on your target choice, an eyepiece giving 150-180x magnification is useful to have as you can use it for globular clusters, planetary nebulae and planets/lunar.

If you often get good seeing where you live, a higher magnification might be useful for planets/lunar, but like Niv said, just consider that more magnification means a dimmer object, so higher magnification is not always better.

What's the focal length of your scope?

[Jon]

Dunk, his scope is f/10 like mine; 2000mm focal length. I recommended a 12mm EP; that gives him 166x magnification, just as you recommended.

For the record the EP I use most, on nebulae and open clusters, is my 2" 42mm Bintel/GSo Superview (http://www.bintel.com.au/Eyepieces-and-Barlows/Bintel-/Superview/Bintel-SuperView-42mm/364/productview.aspx). For $60 you'd have to call it value! That EP would give Steve 47x magnification, and give a pretty nice view of Eta Carina ...

[strummer4]

Focal length is 2000 I think. Thanks everyone for advice. I really find it helpful. What power adapter should I get cos the batteries will run down pretty quickly I think! :confused2:

[Camelopardalis]

(sorry Jonathan, I'd missed your 12mm suggestion)

Sweet, the 8" SCT on that mount should work nicely :)

Like Jonathan says, views of Eta Carina, Orion nebula and open clusters require a nice 2" EP.

Power... unless you'll always be viewing from your garden, you'll want a power tank or get creative with some rechargeables...

[strummer4]

Regarding power, can you get an adaptor that takes power from normal household 240v socket into the telescope port? Or maybe from car battery to telescope port? If so how long is the cable ? Can you observe say up in the backyard and have some sort of extension cord going from the scope to the power socket in the house? If such a thing exits! Ht I it's name nd here can I get one? Sorry for all the questions! :rolleyes:
Steve

[Jon]

I usually use an extension cord running into the back yard - but then I'm powering the mount, dew heater, camera, laptop, powered USB hub, and lightbox!

For portability I use this (http://www.jaycar.com.au/productView.asp?ID=MB3594) which works fine: it has 2 1v DC cigarette-lighter type sockets and also an inverter that means I can run AC if I need to.

Meade makes a plug that powers the mount from a 12v DC cigarette-lighter source. You can get a transformer that will plug in to household AC and convert to 12v DC from Jaycar, Dick Smiths, Bintel ...

[strummer4]

Thanks everyone for input. Based on your advice, I reckon I'll go get the following accessories (when my budget has recovered from the scope purchase)....
X2barlow; 40mm EP; 15mm EP; dew cap; power transformer 240v to 12v; adaptor and t ring to take camera; moon filter; sun filter.
Happy days...I was able last night to point the thing at true north and align it so that when I asked it to goto Saturn, it did!! Amazing. Couldn't have done it without you.

[Jon]

No worries Steve - welcome to what has to be the most enjoyable and fastest way to spend money yet devised ;-)

[strummer4]

Thanks Jon

This is probably a dumb question but
why would I buy a 13mm eyepiece when I could just use my 26mm with a x2 Barlow? Is there any difference? Instead of buying say 4 eyepieces could I not buy 2 and use a Barlow?
Steve

[Jon]

Not a dumb question at all.

As a basic principle, the fewer pieces of glass you put between yourself and the starlight, the better; every optical element will result in some loss of transmission. So, all other things being equal, it's better to go with the EP.

However, all other things are most definitely not equal. For starters, a 26mm EP will usually have a wider exit pupil and give more eye relief. Many observers find it's more comfortable to observe through a 26mm with a 2.5x Barlow than through say a 9mm EP, especially a cheap one. Not all EPs and Barlows are equal. If you can afford a 2.5x Televue Powermate (http://www.bintel.com.au/Eyepieces-and-Barlows/TeleVue-/Barlows-and-Powermates/TeleVue-Powermate-br--2-5x--1-25--/878/productview.aspx), for instance, you'll be effectively doubling the size of your EP collection; with, say, a 32mm and a 20mm EP and a 2.5x Barlow you'll be giving yourself the equivalent of a 12mm and 8mm and I'd find it hard to imagine an observing situation that you wouldn't have covered.

Everyone here will you that the absolute best thing to do when selecting EPs is to get along to an astronomy club and try out other people's kit. Have a look at what the difference is between a 12mm EP and a 26mm + 2x Barlow. There is a whole world of different EP designs, some of which cost about half what you paid for your telescope :-) Everyone's eyes and preferences really are different - for instance I have astigmatism, so finding EPs that allow me to observe with my glasses is important.

Just one word of caution. With your scope, I wouldn't go for a Barlow above 2.5x. That will give your an effective focal ration of f/25 which is about as high as you want even looking at Jupiter and Saturn. The guys with the really fast scopes like the f/5 Newtonians or the short tube refractors need