Galileo FS-90 Reflector Telescope

4535 views
7 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    April, 2009
Galileo FS-90 Reflector Telescope
Posted by Lucid on Sunday, April 05, 2009 12:51 PM

Somebody I know just gave me this for next to nothing because they'd had it for years and had no desire to use it.  I've always had an interest in astronomy, but I admittedly know next to nothing about it.  I would like to change that.  So when you talk to me, act as if you're talking to somebody that has absolutely no clue.  Actually... it wouldn't be acting, it's the truth.

The specs are 800x90mm.  It comes with a 3x Barlow lens, a 1.5x erecting lens, a 6.8-16mm zoom eyepiece, and a 1.25" 20mm eyepiece.  It also comes with a disk "Galileo Planetarium 1.8". 

I've assembled the telescope and synced the finder scope with the telescope.  It's ready to go.  I just have a few questions (I'm sure I'll have more later):

-  Is this Planetarium program that came with it any good, or is it dated now?  Are there some good free programs out there now that are better?  If so, what?

-  I understand that the erecting lens is to make the images appear right side up.  Is this needed, or recommended when looking at objects in space?  Will it have an adverse effect (i.e. distort, darken the image).

-  This 3x Barlow... I've heard that these things can be rendered irrelevant depending on the power of your telescope, and that you may actually not be able to see anything if you try to get too much power.  Does this thing serve any purpose for me?  Would I be better off just using the zoom eyepiece at 6.8 or so?

-  Should a Barlow and the erector lenses be used at the same time?  In the instructions it said to make sure to remove the Barlow lens if you're using it before inserting the erector lens.  I don't know if this means you're not supposed to use the two together, or if it just means the erector lens should be inserted first, directly into the focusing tube, then you can put the Barlow in after that.

And if anybody has any other general advice for me, or about my particular telescope, I'd be grateful as well.  And remember, you are talking to a complete noob here, so try to put things into Lehman's terms if you could.

Thanks in advance Smile

Moderator
  • Member since
    July, 2001
  • From: PA, USA, Earth Moderator
Posted by DaveMitsky on Sunday, April 05, 2009 1:54 PM

Cartes du Ciel, Celestia, HNSKY, Stellarium, and TUBA are all good freeware programs.

http://freeware.intrastar.net/astronmy.htm

Don't use the erecting lens for astronomical observing.  I see no reason to use the Barlow lens with the erecting lens for daytime viewing.

Zoom eyepieces are usually optical compromises with the exception of the very expensive ones.  You may do better with the 3x Barlow lens but perhaps not. 

Most of the accessories supplied with inexpensive, small telescopes are not very good.  You may want to look into getting some better individual eyepieces and a 2x Barlow lens.  Does the telescope have a 1.25" focuser, i.e., do the eyepieces supplied have 1.25" diameter barrels?

Dave Mitsky

Sic itur ad astra!

Chance favors the prepared mind.

A man is a small thing, and the night is very large and full of wonders.

Moderator
  • Member since
    July, 2001
  • From: PA, USA, Earth Moderator
Posted by DaveMitsky on Sunday, April 05, 2009 2:04 PM

I just noticed that you live in York.  You may want to look into joining the York County Astronomical Society or the Astronomical Society of Harrisburg.

http://www.ycas.org/

http://www.astrohbg.org/

The ASH Naylor Observatory, which is located two miles northwest of Lewsiberry, will be open to the public tonight as part of the 100 Hours of Astronomy.  Directions can be found at http://www.astrohbg.org/ASH-i/Directions.html

Dave Mitsky

Sic itur ad astra!

Chance favors the prepared mind.

A man is a small thing, and the night is very large and full of wonders.

  • Member since
    April, 2009
Posted by Lucid on Sunday, April 05, 2009 2:09 PM

Yes, the eyepieces are 1.25" in diameter. 

I was looking at a post in the "accessories" section about calcuating your ideal magnifications given the telescope you have.  It's very informative.  This will probably sound like a really dumb question to you, but the specs for my telescope (800x90mm)...  is the first number the focal length, and the second the aperture?  As I understand the aperture is the diameter of your telescope, correct?  If so I'm getting a different figure than it posted on the box.  Using the posted formula (25.4Xinches=mm), I'm getting 122mm as my aperture (the telescope's diamater is 4.8"), not 80mm. 

I appreciate the help. 

And btw thanks for the links.  I favorited the one for York and I'll look into it.  Heck I might even try to make that tonight.

Moderator
  • Member since
    July, 2001
  • From: PA, USA, Earth Moderator
Posted by DaveMitsky on Sunday, April 05, 2009 4:18 PM

The first number is indeed the focal length and the second the aperture or diameter of the primary mirror or objective lens.  However, only "department" store telescopes are advertised in that fashion.

http://www.amazon.com/Galileo-FS-90-Mount-Reflector-Telescope/dp/B0009HNH3G

I don't know why there is a discrepancy in the aperture unless the optical tube is grossly oversized.

Dave Mitsky

Sic itur ad astra!

Chance favors the prepared mind.

A man is a small thing, and the night is very large and full of wonders.

  • Member since
    April, 2009
Posted by Lucid on Sunday, April 05, 2009 4:42 PM

Ah, here my uneducated self was using the diameter of the entire telescope, and not the mirror.  Looking inside it does look about 3.14", which is what it should be for 90mm.

I appreciate the knowledge.  I've learned a good bit already by browsing the forums here.  BTW... me and a friend are going to Naylor tonight to check it out.  You gonna be there?

Moderator
  • Member since
    July, 2001
  • From: PA, USA, Earth Moderator
Posted by DaveMitsky on Sunday, April 05, 2009 5:33 PM

I'm planning on being there unless the weather forecast really deteriorates.  I'll probably be manning the 17" classical Cassegrain in the French Dome.

Dave Mitsky

Sic itur ad astra!

Chance favors the prepared mind.

A man is a small thing, and the night is very large and full of wonders.

  • Member since
    February, 2007
Posted by ASTRONOMYDOMINE on Monday, April 13, 2009 5:37 PM

My first telescope was a Galileo 60 x 900. I loved it. And it only had .0965 eyepieces. In my opinion, Galileo makes a decent cheap scope. You can use the barlow with your 20mm eyepiece to get 120x magnification. Not bad for planets. Use the 20mm by itself for scanning the sky for star clusters at 40x magnification. Of course, when the astronomy bug bites you, like it did me, you will want to upgrade. But until then enjoy your scope.

Join our Community!

Our community is FREE to join. To participate you must either login or register for an account.

ADVERTISEMENT

FREE EMAIL NEWSLETTER

Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter.

ADVERTISEMENT
ADVERTISEMENT
Find us on Facebook

Loading...