Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

General Astronomy >> Beginners Forum

Pages: 1 | 2 | 3 | 4 | (show all)
Jon Isaacs
Postmaster
*****

Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: RACI finder scope new [Re: pjensen]
      #5833279 - 04/30/13 09:46 PM

Quote:

Quote:

Looking for some opinions on this finder scope. I'm looking to replace my straight through scope on my 8" dob. I'm tired of crinking my neck just to look through it.




Telrad.

Once you get one, you will never want anything else. If it is placed at the top the scope, it is easy to look up at the sky (along the tube) and see exactly what you are pointed at - no guessing. Moving the scope in the correct direction is easy. The time it takes (to do this) is so short that you won't get that neck crink.

Paul




In my experience, Telrad's are great when the skies are dark and clear. When I am out in the mountains, I find most objects with a Telrad. From a light polluted backyard, there are large regions of the sky without sufficient stars to use a Telrad so a magnifying finder that will show the fainter stars is required.

Jon


Post Extras: Print Post   Remind Me!   Notify Moderator  
Haas
sage


Reged: 11/22/12

Loc: Wis., USA
Re: RACI finder scope new [Re: Jon Isaacs]
      #5833364 - 04/30/13 10:38 PM

Quote:

Quote:

Looking for some opinions on this finder scope. I'm looking to replace my straight through scope on my 8" dob. I'm tired of crinking my neck just to look through it.

I'm assuming there isn't too much to worry about since it's just a finder scope? Or, are there things to worry about, things to avoid? Looking for some wisdom on finder scopes. Thanks all!!




Something to consider:

I know that many like RACI finders on their Dobsonians, I prefer a straight through finder. With an RACI finder, you are looking in a different direction than the scope is pointing so pointing the scope to the first guide star requires using either another finder or sighting down the tube. With a straight through finder, I am looking in the direction the scope is pointing, I can keep both eyes open so the finder itself functions as a unit power finder.

I think the most important factor in successfully using a straight through finder is a dedicated observing chair that allows easy adjustment of the seat height. If you are trying to stand or are using a fixed height chair, a straight through finder can be awkward. But with a chair, I find it's quite easy.

Jon




That is a good point. I'll keep that in mind. If I get a Raci, I'll still keep the straight through just in case I don't like it.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Haas
sage


Reged: 11/22/12

Loc: Wis., USA
Re: RACI finder scope new [Re: Haas]
      #5833377 - 04/30/13 10:45 PM

The telrad has my curiosity, but there is a lot of light pollution around here, that has me concerned. I wish there was a way to try a few different ones out before I buy something. I know, a star party, but the only one I know of around here, still has a web site, but apparently no one gets together any more.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Classic8
professor emeritus


Reged: 04/12/06

Loc: Naperville, IL, USA
Re: RACI finder scope new [Re: TexasRed]
      #5833396 - 04/30/13 10:51 PM

Also, with a 50mm finderscope some of the Messier objects can be seen directly in the finder (if light pollution isn't terrible), so they're much nicer in that respect than the smaller 6X30 finders. I love my right angle finders for starhopping.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Haas
sage


Reged: 11/22/12

Loc: Wis., USA
Re: RACI finder scope new [Re: Classic8]
      #5833401 - 04/30/13 10:53 PM

Quote:

Also, with a 50mm finderscope some of the Messier objects can be seen directly in the finder (if light pollution isn't terrible), so they're much nicer in that respect than the smaller 6X30 finders. I love my right angle finders for starhopping.




I think I'm really leaning towards this.


Post Extras: Print Post   Remind Me!   Notify Moderator  
panhard
It's All Good
*****

Reged: 01/20/08

Loc: Markham Ontario Canada
Re: RACI finder scope new [Re: Haas]
      #5833434 - 04/30/13 11:14 PM

Hass the more light pollution there is the less useful a telrad is. Believe me I own both.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Haas
sage


Reged: 11/22/12

Loc: Wis., USA
Re: RACI finder scope new [Re: panhard]
      #5833455 - 04/30/13 11:32 PM

Thanks panhard. I think the 90 degree RACI is the ticket for me.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Kunama
professor emeritus


Reged: 10/22/12

Re: RACI finder scope new [Re: Haas]
      #5833488 - 04/30/13 11:55 PM

For the Rolls Royce of affordable RACI get the Stellarvue F50W2 which has excellent optics, illuminated reticle and interchangeable eyepieces, I often use mine with a 13mm Vixen LVW, makes for a beautiful mini-refractor.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
Re: RACI finder scope new [Re: Haas]
      #5833696 - 05/01/13 05:59 AM

Quote:

Quote:

The 9*50 has a 9 magnification while the 6*30 has a 6 time magnification.




So, is that second number a measurement for field of view?




No, the second number is the diameter of the main lens. It determines how much light the finderscope gathers.

Most decent finderscopes have apparent fields of view around 50 degrees. That means that the true field of view is 50 divided by the magnification. So a 6x30 finderscope typically has a true field of view around 50/6 = 8+ degrees, while a 9x50 finderscope has a (considerably smaller) true field of view around 50/9 = 5+ degrees.

I find both 6x30 and 8x50 finderscopes to be useful. The former has a bigger field of view, but is less likely to show the object that you're aiming for, due to its much smaller aperture. So in practice, you're more likely to use it to get to the right point in the star field than to sight directly on the object.

6x30 finderscopes are also much smaller and lighter than 50-mm finderscopes.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
Re: RACI finder scope new [Re: Haas]
      #5833700 - 05/01/13 06:04 AM

Quote:

Looking for some opinions on this finder scope. I'm looking to replace my straight through scope on my 8" dob. I'm tired of crinking my neck just to look through it.




I love the right-angle finderscope on my 12.5-inch Dob. But you should be aware that a right-angle finderscope does not eliminate the need to crink your neck.

Why? Because you still need to supplement it with something else to get the right-angle finderscope pointed in the right direction. That's unlikely to happen just by feel or guesswork. It could be something as simple as sighting along the tube, though a red-dot or red-circle finder works better. But you still end up crinking your neck to look directly at your target.

The only ways around that are using a green-laser pointer or some kind of electronic or mechanical finding aid, such as a Go To drive, a push-to controller, or old-fashioned setting circles


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jeff2011
Pooh-Bah
*****

Reged: 01/01/13

Loc: Sugar Land, TX
Re: RACI finder scope new [Re: Tony Flanders]
      #5833956 - 05/01/13 09:48 AM

Quote:

or old-fashioned setting circles




+1

I added an azimuth setting circle to my Dob and bought an inexpensive Wixie digital angle gauge. I used it a few nights ago to locate M81 from my light polluted backyard. It worked great. I found it on my first try. It would have been difficult to acheive that using my Telrad since there was not a bright enough star close to it.

I don't have a RACI finder, but I was at an outreach a month ago and one of the guys had one on his Dob. He was using it in combination with a Telrad. I was impressed with how well it worked.


Post Extras: Print Post   Remind Me!   Notify Moderator  
panhard
It's All Good
*****

Reged: 01/20/08

Loc: Markham Ontario Canada
Re: RACI finder scope new [Re: Jeff2011]
      #5833975 - 05/01/13 10:01 AM

Quote:

9x50 finderscope has a (considerably smaller) true field of view around 50/9 = 5+ degrees.


The 5° field of view means with a little adaptation you can use that finder scope with the Telrad finder charts.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Thomas Karpf
Carpal Tunnel


Reged: 02/09/09

Loc: Newington, CT
Re: RACI finder scope new [Re: panhard]
      #5833984 - 05/01/13 10:05 AM

I really like Stellarvue's. It's pricey, and you need to make sure you get the right rings for you scope, but you can use whatever 1.25" eyepiece you want with it, and you can add the illuminator for the reticle later if you want.

Highly recommended.

http://www.stellarvue.com/f50.html


Post Extras: Print Post   Remind Me!   Notify Moderator  
Haas
sage


Reged: 11/22/12

Loc: Wis., USA
Re: RACI finder scope new [Re: Kunama]
      #5833990 - 05/01/13 10:08 AM

Quote:

For the Rolls Royce of affordable RACI get the Stellarvue F50W2 which has excellent optics, illuminated reticle and interchangeable eyepieces, I often use mine with a 13mm Vixen LVW, makes for a beautiful mini-refractor.




Wow, currently unavailable. At least at the first place that google brought up.


Post Extras: Print Post   Remind Me!   Notify Moderator  
kdill2160
journeyman
*****

Reged: 04/02/13

Loc: McHenry County IL
Re: RACI finder scope new [Re: Haas]
      #5834223 - 05/01/13 12:10 PM

Do take a look at the Stellarvue finders, they are very well made, helical focuser, RACI or straight through, uses standard 1.25" eyepieces and comes with a nice 23mm reticle eyepiece, the illuminator is an option... their customer support is the very best, the products I've purchased are all very well made with quality fit and finish...

JMO... Ken


Post Extras: Print Post   Remind Me!   Notify Moderator  
kdill2160
journeyman
*****

Reged: 04/02/13

Loc: McHenry County IL
Re: RACI finder scope new [Re: Tony Flanders]
      #5834247 - 05/01/13 12:18 PM

Quote:

Quote:

Quote:

The 9*50 has a 9 magnification while the 6*30 has a 6 time magnification.




So, is that second number a measurement for field of view?




No, the second number is the diameter of the main lens. It determines how much light the finderscope gathers.

Most decent finderscopes have apparent fields of view around 50 degrees. That means that the true field of view is 50 divided by the magnification. So a 6x30 finderscope typically has a true field of view around 50/6 = 8+ degrees, while a 9x50 finderscope has a (considerably smaller) true field of view around 50/9 = 5+ degrees.

I find both 6x30 and 8x50 finderscopes to be useful. The former has a bigger field of view, but is less likely to show the object that you're aiming for, due to its much smaller aperture. So in practice, you're more likely to use it to get to the right point in the star field than to sight directly on the object.

6x30 finderscopes are also much smaller and lighter than 50-mm finderscopes.





+1 on the Stellarvue, I own the F50M2 and love it, bases on two of my scopes to accept it... JMO... Ken


Post Extras: Print Post   Remind Me!   Notify Moderator  
pjensen
super member


Reged: 04/08/12

Loc: Highland Village, Tx
Re: RACI finder scope new [Re: Jon Isaacs]
      #5834296 - 05/01/13 12:39 PM

Quote:



In my experience, Telrad's are great when the skies are dark and clear. When I am out in the mountains, I find most objects with a Telrad. From a light polluted backyard, there are large regions of the sky without sufficient stars to use a Telrad so a magnifying finder that will show the fainter stars is required.




Or another option is to get a tracking telescope.

With a goto/tracker, the only time you would need to sight through a finder (or telrad) is on the setup (6 stars). This takes me 15 minutes. Then the rest of the night the GoTo puts the objects right in the eyepiece (even at 200x, 0.30* True Field Of View). I don't even need to use the hand control at all (to center it). I don't even need to swap eyepieces (to find the object). It is possible to see dozens of nebula, double stars, clusters all within an hour or two. I can return repeatedly to prior objects that were not visible before - and see them.

As a person who has used (hand push) telescopes all my life, this stuff is simply amazing.


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: RACI finder scope new [Re: kdill2160]
      #5834323 - 05/01/13 12:50 PM

Straight through finders are more sensible on alt-az mounted scopes because of the consistent location. On equatorially mounted scopes there can be positions hard to get to.

In any event, I've long preferred RA finders (and binos) simply because they're more neck- and back-friendly. With practice it becomes easier to get close initial pointing when using RA finders. I do it all the time with my RA bino and its higher power, 4.7 degree field. The aforementioned green laser through the finder eyepiece idea is a good one. You could try it through the scope's eyepiece, too, although at higher powers the beam is expanded (by a ratio equalling the magnification) considerably and hence 'diluted', and you must dodge the secondary shadow in relevant scopes.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jon Isaacs
Postmaster
*****

Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: RACI finder scope new [Re: GlennLeDrew]
      #5834425 - 05/01/13 01:35 PM

Quote:

Straight through finders are more sensible on alt-az mounted scopes because of the consistent location. On equatorially mounted scopes there can be positions hard to get to.




In my experience, RA finders can be a bigger problem with equatorially mounted scopes unless the scope can be rotated in the rings relatively easily. Consider an SCT on a fork mount. The straight through finder may be awkward but at least it will be sticking out the rear of the scope where one can get to it. With an RA finder, it may not only difficult to reach but the eyepiece maybe pointed in some direction so it is unreachable.

Jon
Jon


Post Extras: Print Post   Remind Me!   Notify Moderator  
Haas
sage


Reged: 11/22/12

Loc: Wis., USA
Re: RACI finder scope new [Re: GlennLeDrew]
      #5834435 - 05/01/13 01:39 PM

Quote:

Straight through finders are more sensible on alt-az mounted scopes because of the consistent location. On equatorially mounted scopes there can be positions hard to get to.

In any event, I've long preferred RA finders (and binos) simply because they're more neck- and back-friendly. With practice it becomes easier to get close initial pointing when using RA finders. I do it all the time with my RA bino and its higher power, 4.7 degree field. The aforementioned green laser through the finder eyepiece idea is a good one. You could try it through the scope's eyepiece, too, although at higher powers the beam is expanded (by a ratio equalling the magnification) considerably and hence 'diluted', and you must dodge the secondary shadow in relevant scopes.




Holding a laser through my finder scope seems impractical to me. How could you ever tell that you're holding that laser parallel to the finder scope? Seems like your hand wouldn't really be steady enough for that to work at all.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | (show all)


Extra information
9 registered and 35 anonymous users are browsing this forum.

Moderator:  zjc26138, WOBentley, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1147

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics