Telrad question

[Ande]

Hi all

Just in the process of purchasing new, first telescope. One thing that keeps getting recommended is the Telrad. So it is definitely on my shopping list. Just wondered if anyone had tried the 90 degree adapters that are available for them, and are they any good?

https://www.ebay.co.uk/itm/Telrad-Dew-Shield-with-Mirror-for-90-deg-viewing/162163696720?epid=1517540070&hash=item25c1b5a450:g:~RYAAOSwb69Zu5xs

 

Thanks ?

[russ]

That looks interesting. I have a Telred, and that looks like it might be useful. I have found an active heater on the Telrad is critical to keeping it clear and working in a dew invested area like mine. Slightest hint of dew and the Telrad is rendered completely useless. But i have a Kendrick Dew Heater on it and no problem.

Be interesting to hear what other people's thoughts are.

[russ]

I forgot to say, the Telrad is a great pointing device, wouldn't be without it. Really takes the pain out of lining up the scope on a target.

[Ande]

9 minutes ago, russ said:

That looks interesting. I have a Telred, and that looks like it might be useful. I have found an active heater on the Telrad is critical to keeping it clear and working in a dew invested area like mine. Slightest hint of dew and the Telrad is rendered completely useless. But i have a Kendrick Dew Heater on it and no problem.

Be interesting to hear what other people's thoughts are.

Looks like I’d better add a heater to the ever-growing list too, lol ? 

[russ]

5 minutes ago, Ande said:

Looks like I’d better add a heater to the ever-growing list too, lol ? 

Ah no, don't do that. lol   You maybe okay where you are. Get the Telrad, see how it goes. That dew shield maybe all you need even if there is a dew problem.

[Ande]

You look after my money better than I do, lol. Thanks, I need a bit of restraint cos I’m all fired up and dying to get started. Looked at so much stuff over the last week that the mind boggles.

[Tomatobro]

I have considered getting one of these 90 degree viewers several times but wondered how you compare the area of interest with what you can see. For best accuracy your eye needs to be some way away from the reflected circle so that you can see the surrounding star pattern outside of the Telrad as well as the positioning star itself. 

[Louis D]

Well, the whole point of a unit power finder is to project a pattern on the night sky so you can align your scope to the area of interest.  If you're looking at 90 degrees to the sky, it doesn't seem like it would be very useful.  I keep both eyes open and merge the projected finder circles seen in one eye with the sky view seen in my other eye.  Looking at 90 degrees in the Telrad, my other eye would be looking at the ground or the scope.

BTW, how big is your new scope?  Telrads are fairly large and do best on bigger OTAs like 6" and up Newts.  For smaller scopes, I prefer the Rigel QuikFinder.

[Littleguy80]

It's really easy to make a dew shield for the Telrad. Here's my effort

I think it's better to look straight through the Telrad rather than at reflected image. I often use stars outside the 4 degree circle as a guide to placement. You obviously can't do that if you're only looking at the reflected image.

[mikeyj1]

i like my telrad also, but the dew is the major problem from Oct to April.  i don't like the right angle viewer shown (design or price!) and would suggest you consider the heater as a priority...but you can do that yourself as shown in the attached, or have a dew heater version as mentioned

Mike

[russ]

36 minutes ago, mikeyj1 said:

i like my telrad also, but the dew is the major problem from Oct to April.  i don't like the right angle viewer shown (design or price!) and would suggest you consider the heater as a priority...but you can do that yourself as shown in the attached, or have a dew heater version as mentioned

Mike

I was going to mention the 90deg bit as i couldn't really see how that would work with the Telrad being a zero power finder that you use with the sky and both eyes. Looking down into a mirror though a small hole doesn't sound great. The homemade heater above looks perfect.

[Louis D]

1 hour ago, russ said:

Telrad being a zero power finder

Technically, a unit(ary) power finder (i.e., 1x).  0x would shrink the entire sky to a point.

[Ande]

Right, that’s quite resounding then. Now crossed off the shopping list. Thanks all ?

[russ]

50 minutes ago, Louis D said:

Technically, a unit(ary) power finder (i.e., 1x).  0x would shrink the entire sky to a point.

Technically that you are right but also its technically applying no (zero) magnification over and above regular vision.

[martinl]

I have a flip-mirror on my TeleVue Starbeam red dot finder and I almost never use it. The field of view using the mirror is simply too small and you lose the main benefit of unit power finders, which is that you can look at the sky with both eyes. Much more natural for navigating. 

Dew/frost is often a problem with Telrads though, however I’ve found that a simple home made dew shield like Littleguy80 posted is usually sufficient. I made mine from 2mm foam from the local craft store and some self-adhesive Velcro. A side benefit is that the dew shield also cuts down on glare from street lights and other light sources. 

[Stu]

I agree with comments made. I did have one of the shield/90 degree mirrors but didn't really get on with it.  As said, you really need to view the circles against the wider star field to be able to position the scope properly. A homemade dewshield works very well, better in fact than the shield/mirror one.

[Ande]

Thanks everyone. You’ve enlightened me considerably.  And I apologise for the inevitable dumb questions that I shall be firing your way in the coming weeks and months ?

[Eastman]

6 hours ago, Louis D said:

I keep both eyes open and merge the projected finder circles seen in one eye with the sky view seen in my other eye.  Looking at 90 degrees in the Telrad, my other eye would be looking at the ground or the scope.

+ 1

It really helps to find fainther stars.

A telrad was by far the best upgrade on my scope!

I use the telrad cover without the mirror, but I often forget to place the dew shield back 

[Gabby76]

I have used the dewshield+ for quite awhile and it can be handy. It is like any other new piece of gear though. 

Once you have it located conveniently you will not have issues using it.