128 replies to this topic

[Craven]

I read 5-star review after 5-star review about what an incredible upgrade the Telrad is and how it makes finding objects so much easier.  How does it do that?  One still has to locate the desired object and get Telrad over it first, correct?    I have an original red dot finder that come with my 8SE, and it has a red dot, but i still need to put the dot over my object.  It doesn't nec make objects easier to find.   Whats so great about a Telrad?

[clearwaterdave]

I tried to like my telrad but it.,like any straight through type pointer is a pain to view through when the scope is pointing skyward,.,It does do what it's supposed to do.,which is show you where your scope is pointing.,but ""FOR ME"" it was a pain in the neck. no pun intended.,I use a glp to aim my scope.,and couldn't be happier.,

[Waddensky]

One still has to locate the desired object and get Telrad over it first, correct?

No, you locate the object by getting the Telrad over it. The circles enable you to align the telescope by comparing the field stars you see to a finder chart with the Telrad circles plotted on it.

 

Here's a detailed instruction.
 

[erick86]

A Telrad & dot finder are in the same class — they provide an unmagnified, straight-through view of where your scope is pointing. If you don’t like using a dot finder, you probably won’t like using a Telrad either.

I love the telrad, and have used one exclusively on my scope for 20 years. However this likely depends on your scope. I have a fairly short focal length (8” f/6) and as a result I can get very low power through the eyepiece. I have no need for a finder scope when I can get as low as 30x magnification. I can just point the scope to where an object should be, relative to the stars around it, and boom there it is!!

If you have a Schmidt cassegrain or something with a very long focal length, then I can see where the frustration would stem from. It can be very hard to find anything with a Telrad/dot finder if you can’t get the power low enough in the field of view to sweep for an object or get your bearings as to exactly what area you are looking at in the eyepiece.

Eric

[Jon Isaacs]

I read 5-star review after 5-star review about what an incredible upgrade the Telrad is and how it makes finding objects so much easier.  How does it do that?  One still has to locate the desired object and get Telrad over it first, correct?    I have an original red dot finder that come with my 8SE, and it has a red dot, but i still need to put the dot over my object.  It doesn't nec make objects easier to find.   Whats so great about a Telrad?

 

The Telrad helps in locating the desired object.  

 

Most objects are not visible naked eye, most objects are not visible in a magnifying finder.  This means that to point the telescope at an object, you position it relative the visible stars, things you can see.

 

The Telrad has calibrated rings that are 0.5°, 2° and 4° in diameter.  You can use this calibrated reticule to accurately judge the relationship with the star field.  Many software programs like SkySafari provide Telrad circles so pointing your scope simply means matching what you see in the Telrad with the chart. 

 

It's also useful for measuring large distances under light polluted skies. 

 

Red dot finders are overly bright for dark sky use, the Telrad can be turned down so its barely visible.

 

I use a combination of a Telrad, a 50 mm RACI finder and a lower power 2 inch wide field  eyepiece. The Telrad gets me close, the 50 mm and lower power eyepiece do the rest. 

 

With your 8SE, you are using GOTO to find objects and the red dot just to for initial alignment.  The red dot is all that's needed. Telrads are a favorite tool of star hoppers, you don't see many big Dobs without a Telrad. 

 

Jon

[Mr. Pepap]

A Telrad is basically just a glorified dot finder, but I really like them.

 

I find that the concentric circles make centering objects much easier.

 

It also is very big, which gives a wide field of view for easy starhopping.

[eyeoftexas]

I use a Telrad when I'm at my dark site, for all of the reasons stated in previous posts, and enjoy using it.  In my backyard under Bortle 7/8 skies (SQM = 18.2), however, it is not very helpful because the number of naked eye stars are minimal.  In this case, I use a red dot finder to help align my scope with a couple of stars and then use GoTo to find the targeted objects.  Using a wide field ocular allows final accurate locating using SkySafari if the GoTo is off.  

[kel123]

I read 5-star review after 5-star review about what an incredible upgrade the Telrad is and how it makes finding objects so much easier. How does it do that? One still has to locate the desired object and get Telrad over it first, correct? I have an original red dot finder that come with my 8SE, and it has a red dot, but i still need to put the dot over my object. It doesn't nec make objects easier to find. Whats so great about a Telrad?

Your question could have as well been, "what makes finder scopes special? Because it is basically the same principle.

If you are gifted enough to find dim objects without finder scopes, then you are exceptional.

Finder scopes (or red dot finders) generally have much less magnification (or no magnification at all) and much wider field of view than your telescope.

When you put your finder scope over the targets, it helps you to find the object with your telescopes much easily as it means your telescopes will be pointing at the same spot.

With the limited field of view of your telescopes, coupled with the fact the the images might be inverted, it is more difficult to find object directly with the telescope.

Yes, the aim of the finder scope is to see the target or position of the object with your ordinary eyes, like you already do and place your finder scope over it, so that it ensures that your telescope is pointed at the same object.

This last point makes me think that perhaps there is something missing from your question. Perhaps you didn't know that your finder scope or red dot finder needs to be aligned with the line of sight of your telescope, so that they will be pointed at the same target , in order to find objects easily with your telescopes.

So, calling it a finder does not mean it will magically find an object by itself. You still need to find the object with your eyes and place the finder on it, then it will find the object for your telescope.

People love Telrad because of its lack of magnification, lack error due to parallax and concentric rings. It makes it easier to find targets with your telescope after aligning its line of sight with the line of sight of the telescope .Normal finders still have some degree of magnification and you might still not find objects easily with them but telrad is straight-through ensuring that what you are seeing with your eyes is what you are really pointed at with your finder and with your aligned telescope.

Let's say you want to find a very dim object and you know that it is half a degree or 30 arc minutes from a particular named bright star, Because the smallest circle in a Telrad is half a degree in diameter, you place one end of the ring next to the bright star, and you know that the object should be at the other end of the ring. Then, you point at this position and look into you telescope and observe your target.

Let's say you want to split a particular double star. Just place it in center of the ring and your telescopes will be pointed at it.

The telrad has 3 circles which are of different diameter in degrees and you basically use them to measure the sky to the position of your target. And the circles are dimmable ,so that that they wouldn't cover what you are trying to point at.

Without a telrad or a finder, you will find it difficult to point directly with your telescope. You may even be pointed at the wrong star. But with a telrad or finder scope aligned to the line of sight of your telescope ,you know that you are definitely pointed at the right star or target.

Edited by kel123, 23 March 2021 - 09:42 AM.

[careysub]

The dot in the red dot finder is a defect. It typically cannot be dimmed and actually obscures the object(s) used for location as you attempt to place it.

 

The inner ring of the Telrad is an intrinsically superior approach, plus it can be dimmed as needed, which is very important.

[rhetfield]

Basically, the telrad is an improvement over the other red dots that one can get.  As others have pointed out, it is the only one with the circles with specific degree sizes and can be made dimmer than any of the other red dots.  It also holds bigger batteries and will run for longer as a result.  Of course it is also an inexpensive device.  In addition to being able to set up Sky Safari to show the telrad circles (or any other field of view circle you might desire), there are many charts in print that show the star hopping paths to popular targets based on a telrad.  This was the method available to the old timers in the "good old days" and they swear by it and are the ones giving out the good reviews.

 

The disadvantage is that they are big and clunky.  If someone made a version that was not too big for my little scope, I would have one.  Instead, I have the smallest red dot I can find, a set of degree circles that can dial into within 0.25 degrees, and a field of view of 2.5 degrees through the eyepiece.  Not to mention light pollution that may be somewhere between bortle 7 and bortle 9 depending on who one asks.

[Asbytec]

I liked using mine.

[RalphMeisterTigerMan]

What's not so great about it?

 

Clear skies!

RalphMeisterTigerMan

[Jethro7]

Hello Craven,

It's cheap and it works like a charm.

 

HAPPY SKIES AND KEEP LOOKING UP.

[SloMoe]

I have one so that when I ask Chuck where is the target it's easy for him to find stuff up there for me.

[psychwolf]

Nobody mentioned this, so I'll note it - in addition to all of the great points above, some star charts are designed specifically for Telrads. They use the concentric circles as checkpoints in the sky, so if you get lost in your zooming around, you restart back to the checkpoint. I have many goto options, EAA options - but I still enjoy visual astronomy with a telrad and a telrad star chart to learn the sky in a different way than learning the sky with computer. 

 

Brent Watson makes very decent star hopper series charts that are laminated - I enjoy those. Here's for the Messier Marathon this month -

Ultimately I imaged about 59 in one night with the Unistellar eVscope, but while I was doing that I also enjoyed the slower path with a Telrad alongside, assuming I'll get quicker with experience while enjoying an alternative view visually on the same objects.

 

[Hexley]

I get by just fine with standard $30 red dot finders, however, all of my scopes are on a Go-To mount (6SE/ST80) or have a push-to system (Dob). I only use the RDF to find my alignment stars and typically "fly by computer" for everything else (although on the Dob I can obviously go manual)

 

Also, all the current-gen red dot finders have a dimmer, which works fine if your sky is dark.

Edited by Hexley, 23 March 2021 - 09:22 AM.

[ayadai]

With your 8SE, you are using GOTO to find objects and the red dot just to for initial alignment.  The red dot is all that's needed.

It was a bit of a catch-22 with my 8SE. Unless alignment was spot on, goto was consistent, but off a bit. To more easily get an accurate alignment, a 12mm illuminated reticle eyepiece (IRE) was employed. However, the red dot finder could only get the rough position of an object, which was not quite good enough to get it visible in the IRE. It was necessary to use a 25mm or higher eyepiece, center the object, switch to the 12mm IRE, then center again.
 
The solution was a 9x50 finder scope with reticle. With the 9x50, I can easily get the object very near to center on the IRE. Add the GLP to this, and alignment is fast, fun and easy. Also, if I see something interesting either with or without binoculars, it's simply a matter of turning on the GLP, slewing to the object, centering it in the 9x50 hit identify on the handset, observe and research.
 
As others have observed, the telrad is quite large, and for me, not accurate enough for the purposes described above. Note, however that I do still use the original RDF to facilitate the initial alignment of the GLP or in case there are any planes about.
 
One option to the stock RDF is the Celestron StarPointer Pro Finderscope. Much smaller than a Telrad, less expensive, and it has circles, rather than a dot, like the Telrad.
 

The dot in the red dot finder is a defect. It typically cannot be dimmed and actually obscures the object(s) used for location as you attempt to place it.

Please note that the RDF that comes stock with the 8SE is dimmable.
 

Edited by ayadai, 23 March 2021 - 09:28 AM.

[gene 4181]

 If you've ever scaled a blueprint  then you will see the efficacy of the  the Telrad and the 4,2 and 1/2 degree circles that are superimposed on the sky looking thru it.   Even your pocket atlas has a "scale " to it, the telrad circle is in the front cover ..... superimpose the telrad circle over your object of interest  and overlay the stars the same as in the chart  and you'll be within a circle search of  your object  with a known 1 degree FOV eyepiece.     TURN OFF your Go Too and show me  M-57   or the Clown nebula in Gemini  ,   20 years ago before Go -Too it was straight thru optical   and Telrads

[Oyaji]

Pricey, but blows away the Telrad and every other red-dot I've seen:  https://www.baader-p...dot-finder.html

[ayadai]

20 years ago before Go -Too it was straight thru optical   and Telrads

Correct, but as Jon also correctly observed, goto, which is ubiquitous now, obviates the procedures you described. All navigation, charts and scales are computerized and integrated, rendering paper obsolete.
 

Pricey, but blows away the Telrad and every other red-dot I've seen: https://www.baader-p...dot-finder.html

That's a cool gadget. What could really be a game changer would be a zoom 50mm RACI with independently illuminated reticle and circles.

Edited by ayadai, 23 March 2021 - 10:03 AM.

[davelpg]

I prefer looking for and at stuff toward the zenith.  Also prefer not getting a stiff neck, so I prefer using a RACI finder.  Works for me, so no Telrad in my (small) arsenal of stuff.  Of course, YMMV.  

[therealdmt]

Correct, but as Jon also correctly observed, goto, which is ubiquitous now, obviates the procedures you described. All navigation, charts and scales are computerized and integrated, rendering paper obsolete.

You might be surprised, but a lot of us don’t want a computer finding stuff for us. GOTO might be ubiquitously available for purchase, but it isn’t ubiquitously purchased. Not that there’s anything wrong with GOTO, just saying that that’s not what some people want out of the hobby.

 

Now regarding paper, i’ll admit I’m pretty much with you in that I don’t use or have any interest in carrying books or pages — but clearly other people, including right here in this thread, do

[ayadai]

You might be surprised, but a lot of us don’t want a computer finding stuff for us. GOTO might be ubiquitously available for purchase, but it isn’t ubiquitously purchased. Not that there’s anything wrong with GOTO, just saying that that’s not what some people want out of the hobby.

 

Now regarding paper, i’ll admit I’m pretty much with you in that I don’t use or have any interest in carrying books or pages — but clearly other people, including right here in this thread, do

I don't find it surprising at all; everyone finds joy in this venture in their own way and if someone is well versed, proficient and satisfied in their methodology, far be it from me to gainsay that. To the point of the OP, however, who has a GOTO scope and is wondering what a Telrad can to for them, I'd say "probably not a heck of a lot". All things in context...

[skybsd]

Hello, 

 

I read 5-star review after 5-star review about what an incredible upgrade the Telrad is and how it makes finding objects so much easier.  How does it do that?  One still has to locate the desired object and get Telrad over it first, correct?    I have an original red dot finder that come with my 8SE, and it has a red dot, but i still need to put the dot over my object.  It doesn't nec make objects easier to find.   Whats so great about a Telrad?

For my observing needs and process, I too find them useless. 

 

skybsd 

[kel123]

Hello,

For my observing needs and process, I too find them useless.

skybsd

I guess you miss the point of the question and this post is not helpful to a newbie who doesn't understand the concept of a finder.