Telescope Questions & Reviews

nevers · Oct 18, 2004

Here's a picture of the books (Skywatching by David Levy) Alex was talking about. Along with it is another book I really enjoy: Peterson's Fieldguide - Stars & Planets. The book is more compact and has a lot more information and lots of star charts with many more objects on each chart. It's about the size of a paperback book. The Skywatching books are rather large (but have nice pictures!): about the size of coffee table books. The other pictures are of fold-out maps. One, Phillips Moon Map and my favorite map of all: Orion's DeepMap 600 by Wil Tirion.

nevers · Jan 6, 2005

*** (RiflemanNL got a new 'scope: the space below is for him to give us a review of it) *** Or...anybody else that has not posted about a new 'scope!. <img src="/images/icons/smile.gif" />

nevers · Feb 19, 2005

Hmmm...it appears we never got our review! Anyway, I used to have this Eyepiece Calculator Program. A while back when I got a new computer I lost the program and have been searching for it ever since. I finally found it - it's called TelOptiCulator. I tried a dozen or so download sites from Russia to the US without any luck. I finally found a place that still has it. You can download it here if you like: TelOptiCulator. The site is in Spanish and obvious enough to figure out and the program is still in English.

bbrock · Feb 19, 2005

Brad I have a question for you. CrazyEddie might have some ideas also. I got the AstroView 120ST and finally got a chance to try it out. The first night out I noticed I coulden't focus at low magnification ( <60x ). I jumped to 100x and had no problem. I thought I was just cought in a brief upper level wind storm. Then next night I decided to try it again. Sure enough. at 18.75x (32mm) I coulden't get a sharp focus. The best I could do was a small star splash that looked like tiny doves. I tried 24x with a 25mm and got the same thing. When I went to the 10mm at 60x the problem vanished. Anything at 60x and higher -- all the way to 300x looked great ( gets pretty dark at 300x ). Especially with the aperture mask. So why the problem at low magnifications? Great Telescope. Limiting this scope to 150x is bull &%$#@!. But you need to use the aperture mask ( f/12 ) or a V-Block filter at 150x and greater magnification. Any thoughts on the problem? Bill

nevers · Feb 19, 2005

Hi Bill, That is very odd and I'm sorry you've got that problem. I checked out some stats and it says your 'scopes lowest magnification should be 24x. I remember when I looked through the Orion 120ST at GCSP, the view was really wide but I'm not sure of the size of EP the owner had in. Have you thought about the Orion Expanse Series EP's? The 20mm with your 'scope will give you 30x with a 2.2 degree FOV. Have you seen this website? Scopulator Keep us posted. I'd like to hear Crazies answer. He probably knows the how's and why's. I'll bet Thom knows too.

nevers · Feb 20, 2005

For the first time in my life I spent part of my tax return instead of saving it. If you care to read, it's part observing session/scope review/ranting on my part - Well, I’ve gone and done it: I ordered another telescope and it got in yesterday! At one point last week I thought I wanted to buy a 17.5” Discovery Dobsonian (with the works!) from a man who lived in Las Vegas and was selling it on Astromart. Luckily, Thom and Ron talked some sense into me and I quickly forgot about. I already have a nice mirror in my 16” Dobsonian. At this point I’d like to just downgrade the secondary mirror and upgrade the mirror cell. Those can wait for another day. What I really wanted/needed was a guide scope for the LXD55-AR5: it was just a matter of which ‘scope to get. I already tried piggy-backing the Orion AstroView but it seemed far too heavy for the motors. Some people at LXD55.com said it should be ok but I didn’t like the sound the motors made. It seemed like it was straining when attached. I’d been looking at some ‘scopes sold by Apogee but their site has poor pictures and the information I received from the company was sketchy at best. I did see some small refractors for sale at a pawn shop but they were all beat up and not worth what they were asking for which was nearly the same as brand new. I even found a very affordable 80mm short-tube at Big 5 Sports that was made by National Geographic. That too was like most Wally-Mart ‘scopes: plasticy. As usual, I’d been scanning the clearance section at Orion and have found a few good candidates. I really liked the Starblaster that I’d seen at GCSP and there are some nice Equatorial Newtonians at Orion. The problems I have with Newtonians is that the position of the eyepiece sometimes ends up in an odd place and has to be rotated in the rings: this won’t do in a ‘scope that’s being used as a guide scope. They would also probably be too heavy for what I want. Orion does have a little ST 70mm f/5 refr

nevers · Feb 20, 2005

I didn't know where to post this but you gotta see it! I was searching ebay, and well, this person might need some help someday...at least the price is pointed in the right direction! Here's the link if you can't wait for the picture Misguided Meade I'm not sure how long it will last...time left for bids says 3 hours but there have been no bids to date...

bbrock · Feb 20, 2005

Brad Thanks for the reply. Where did you find the stat for the AstroView 120 ST? " Minimum Magnification = 24x ". If that is true, then this might make sense. Perhaps the optics are not optomized for this low range. I have followed up with a question to Orion Tec Support. Congratulations on your purchase. I'm a little ignorant regarding guide scopes. I know folks into astrophotography do this, but I don't understand why. If the main scope has RA tracking, and you have a spotting scope, what is the purpose of a guide scope? Bill

nevers · Feb 20, 2005

Hi Bill - The link for the 'scope limitations is posted above: the one called Scopulator But I'll be interested in hearing what Orion says: if you could let us know too? Even though I have a "GoTo" in the LXD55-AR5, it is not perfect in centering objects in the EP when I slew to them. The SteadyPix Camera Mount (it's attached to the EP in the picture) is also not a perfect tool at centering the camera over the EP. Vignette is also a problem and gets worse at high power. Sometimes I'll think I have everything lined up only to find out the object I was taking pictures of turns out to be near the edge of the FOV and not centered in the picture frame. Taking everything apart and readjusting is a hassle and a problem I'm trying to avoid. With the guide scope, I'm hoping that I can get everything lined up better. If I'm off a little, I can use the guide scope to adjust the image in the camera without having to take everything apart on the main 'scope. This will really come in handy when taking pictures at higher powers and in slewing to a different object. That's what I'm hoping for anyway. We'll see how it goes. First I need clear skies...

bbrock · Feb 23, 2005

Hello crazy This is an interesting problem. The AstroView 120ST is a refractor. I have used the EP's before on the 10 reflector and they worked good. I have two 25mm plossel's and I tried both of them. Both give the same results. Orion is puzzled and don't have an answer. I am waiting for a 20mm expanse EP and will try it to see if I get the same results. I'm going to report the results to Orion. Is it possible that the diagonal could be giving the distortion at low magnification? Orion insists the diagonal that shipped with the scope is a mirror diagonal. The only problem is the immage is a correct image, not reversed. Can a mirror diagonal give a correct image? Clear Skies Bill

nevers · Feb 23, 2005

Speaking of the diagonal...you are using the one supplied with the 'scope right? Because I have a Meade 2" Diagonal with the 1.25" adapter and when I put it on the 100mm AstroView, I can't use anything except a 2" EP: the 1.25"'s won't focus no matter what mm.

bbrock · Feb 24, 2005

Crazy and Brad I am using the 90 diagonal supplied with the scope. Crazy has just mentioned something that I need to check out. The image is a correct image, but I need to re-verify that left is left and right is right. The new EP's should be in tomorrow, and the sky should be clearing tomorrow with a clear sky Saturday. I will get to the bottom of this. ---- I will compare the 32mm, 25mm and 20mm, 10mm and 9mm ( The 20mm Expanse was Brads idea, but I wanted one anyway ). I wish I had a different diagonal to compare with. I will test this on bright stars only, probably the Pleiades. I'll let you know how this turns out. I wish I was equipped for photography. I would need to take a movie with the focus slowly passing through prime focus to show what is occuring. Clear Skies Bill

bbrock · Feb 26, 2005

Regarding the Focus Problem I once again had the chance to investigate the AstroView 120ST low mag focus problem. I started out with similar results. I used a bright star in the Pleiades ( Alcyone ). The 32mm plossl had flaring at prime focus. Lets call it 100% of the problem. I then used a 25mm plossl and had about 50% of the flaring I had with the 32mm. I received the two expanse EP's and used the 20mm Expanse next. The flaring was virtually gone. I then tried the 10mm and 9mm and the results were the same as before. No problem with the higher magnification EP's. Then I decided to change targets. I put in the 32mm plossl and targeted the double cluster. I wanted to re-position the angle of the EP so I loosened the 2" adapter thumb screw instead of the diagonal. I rotated the whole unit around the 2" focuser shaft and re-tightened it. I focused the 32mm EP and I could not get the flaring problem I had before. I then loosened and re-tightened it again. I coulden't get the flaring problem to re-occur. ????? OK. so this doesn't make sense. I suppose the 2" adapter was cocked a little sideways and needed to be re-aligned. So how is it that the image looked better at higher magnifications??? With that, I started chasing Messier objects. I thought someone might like to know. The 20mm Expanse is awsome. Clear Skies Bill

nevers · Feb 26, 2005

Hi Bill - I'm glad you solved your problem although I'm unclear as to what you did exactly to fix it!?!?!?! I'm also glad you liked the 20mm Expanse. I was worried that you would hate it and blame it on me! The other EP's offer much the same FOV: much bigger then standard Plossl's at the higher powers. I must say, not only am I jealous of your 120ST, I'm more jealous that your getting to observe! <img src="/images/icons/wink.gif" />

bbrock · Feb 27, 2005

Brad I'm not sure I fixed anything. There are two thumb screws that hold a tapered sleve for the two inch adapter. I think one thumb screw was tight and the other was loose. There is a little play in the unit and it seems it was cocked to one side. None of this makes sense to me. I can't even duplicate the problem. I do know that I rotated the eye piece unit with the 2" adapter instead of loosening the diagonal and rotating it. I had never did this before. When I titghtened the whole thing the image with the 32mm looked good. Which it wasn't real bad to begin with, but the stars were suddenly points of light instead of tiny flared points. OK, maby I was being overly picky. But I have no idea what happened. The 20mm Expanse gives a marvelous FOV, with only slight abervation around the endges. Very bright, nice and sharp in the center. This is a good deep sky EP. Bill

nevers · Feb 27, 2005

If it's not fixing, don't brake it...or something like that. <img src="/images/icons/wink.gif" /> I'm glad you liked the EP...some nights it's the only EP I use.

bbrock · Feb 28, 2005

Brad I received a reply from Orion Tech Support. Keep in mind that I have had about the same conversation with Orion that I have posted on this thread. Their explination seems to be the best one going. Considering there are no others, I'm happy with it. As Follows, copied from their reply today, 2/28/05. Hello Bill, We're also a bit baffled how this could be. The only thing I can attribute this to now is a form of an internal reflection. If the flaring resembled a "ghost" image of the star then you may be experiencing glare caused by internal reflection when the 2" eyepiece adapter was slightly skewed. This misalignment probably wasn't enough to actually cause distorted optical images (the stars would have remained points at all magnifications). But it was enough to show some ghosting of the star. I suspect an object like Jupiter or Venus would have sown this flare the most. Higher magnifications were probably dark enough to eliminate the ghosting while your optical axis was still collimated well enough for a good star point. Thank you, Orion Technical Support And Indeed, the brightest objects were the problem. Lower magnitude objects did not show this flaring or gosting. So there ya go. Clear Skies. Bill

bbrock · Feb 28, 2005

Oopps, I meant higher magnitude objects. Bill

nevers · Mar 1, 2005

So there ya go...! <img src="/images/icons/wink.gif" /> Glad it's solved! Do you think they could explain all the cloudy, rainy weather?

bbrock · Mar 1, 2005

Well If the Earth wasn't trying to cool itself off we woulden't have that problem. On the other hand, I've been in a droutht. Ever since then I swore I would never complain about rain. I guess I'll see. Bill

tfwthom · Mar 1, 2005

Who's mirror is in the StarMaster? <div class="Discussion_UserSignature"> www.siriuslookers.org </div>

bbrock · Mar 2, 2005

I've been wanting to ask someone about mirrors and I keep forgetting to ask. For reflector primary and secondary, what would be considered a good mirror and how is it measured or compared. I have an Orion 10" reflector. I have no idea if this is a good or great or poor primary and secondary mirror. I've heard someone mention getting a mirror re-coated. Why, Where and by Who? All of this mirror stuff is new to me. Where can I find this information? Bill

tfwthom · Mar 2, 2005

OK Lets talk a bit about mirrors, I'm not strong on them, I'm a refractor/SCT guy. http://www.bpccs.com/lcas/Articles/scope5.htm for a bit of basics Here's some top mirror makes (in no order) Torus http://www.opticalmechanics.com/ Galaxy Optics http://www.galaxyoptics.com/ Nova http://www.nova-optical.com/ Intermountain Optics www.intermountain-optics.com Pegasus Optics http://www.pegasusoptics.com/ Swayze Optical http://www.europa.com/~swayze/ Zambuto Optical Company (Wholesaler) Mike Spooner (if you have a year to wait) These only become important when you are spending like $10k for a 25" Obsession. For something like a 10" Orion you take what you get, it's not worth messing around with a small mass produced mirror.(unless you are into ATM) <div class="Discussion_UserSignature"> www.siriuslookers.org </div>

emperor_of_localgroup · Mar 8, 2005

anyone here has a Celestron Nexstar 8i or 5i? I'm new with telescope. so, i'm throwing this question to anyone who knows anything about tel. I recently bought a Nexstar 8i with 'find it', but when i look through it i dont see much differnce from what i see without tel? the moon looks like a giant blob of light, no features. distant stars look a little brighter, that's it. shouldn't i see more stars in the sky than in see with naked eyes? i'm sure my setup isn't right. any suggestion'd be appreciated. if anyone has any pic of the moon with an nexstar 8i, please post or email me it so i can compare. <div class="Discussion_UserSignature"> Earth is Boring </div>

bbrock · Mar 8, 2005

At a very fundamental level. We assume you have put an eye piece in the eye piece holder and have tried to focus the telescope with it in. Try the lowest power eye piece ( Eye Piece with the highest number printed on it, which is the focal length of the Eye Piece ). You can't just look into the scope eye piece holder and expect to see anything. Assuming you are doing this, then there is someting else going wrong with the scope. As crazyeddie stated, next you need to make sure the optics are aligned by checking the collimation. Check the Eye Piece to make sure the lens surfaces are not covered with anything and are clean and clear. Don't touch them with anything, just check them. Let us know what you find out. Bill

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