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rusty
Joined: 17 Sep 2006
Posts: 4
Location: Rockhampton, Australia
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 Posted: Sun Sep 17, 2006 11:36 am Post subject: View Finder |
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Hi All
I am thinking of purchasing a Telrad to put on my Dob, not in place of the finder scope but next to it. I have read a Telrad makes locating objects heaps easier.
I would be interested to hear other people's experiences with a Telrad on their Dobs.
Cheers
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70mm Meade Refractor
(Soon to be in possession) 250mm GSO Dob |
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Pop Finch
Joined: 20 Sep 2006
Posts: 2
Location: South Australia
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| Posted: Wed Sep 20, 2006 12:30 am Post subject: Telrad |
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I have had a Telrad as my only finder scope on my 8inch Dob and I find it quite good.
I also useSky Atlas 2000 they work well together. |
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gronk
Joined: 21 Sep 2006
Posts: 3
Location: Sydney, Australia
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| Posted: Thu Sep 21, 2006 4:08 am Post subject: |
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I have used a Telrad as the only finder on my 25 cm Dob for years - I love it!
I do a bit with open nights, schools etc, and the kids really enjoy being able to see the bulls-eye of where the telescope is pointing. It takes away the intimidation. As an extra bonus, I positioned the Telrad so I can stand on the opposite side from the people viewing, and keep it on track.
Just be careful where you mount it, so you don't breathe all over your eyepiece and fog it up. |
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rusty
Joined: 17 Sep 2006
Posts: 4
Location: Rockhampton, Australia
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| Posted: Sat Sep 23, 2006 9:59 pm Post subject: |
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Sounds like some good advice, thanks.
I was also wondering if there is a method of securing the Telrad to the OTA that ensures the Telrad is lined up correctly?
Thanks.
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70mm Meade Refractor
(Soon to be in possession) 250mm GSO Dob |
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gronk
Joined: 21 Sep 2006
Posts: 3
Location: Sydney, Australia
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| Posted: Sun Sep 24, 2006 11:16 pm Post subject: |
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I never found alignment to be a problem, because the Telrad's base is tent-shaped so it automatically aligns reasonably well, then the three adjustment knobs gave plenty of correction.
If you are more careful than me, you could always test it out by attaching first with Blu-Tac. Then you could fix the alignment during the day by using the moon or something else that is very, very far away (NOT THE SUN!), as follows:
1. Put your widest-field eyepiece in, and locate your target in the middle of the telescope field.
2. Then adjust the Telrad until that object is in the middle of the bulls-eye.
3.Check again that it is still centered in the telescope, and repeat the steps above until you are happy that it is aligned nicely.
4.Mark up the Telrad's once you are happy with it, and attach it there. |
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justin138
Joined: 28 Oct 2006
Posts: 3
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| Posted: Sat Oct 28, 2006 8:01 pm Post subject: |
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I have acquired a Rigel Quik Finder which is similar to the Telrad but has a much smaller footprint. This is fixed to the OTA by double sided pads which hold it nice and steady.
It took me a while to get used to it (especially keeping both eyes open to use it) but I find it very nice to use. The only thing is the window is prone to dewing up which I understand is also a problem with the Telrad.
My tuppence worth!
Justin
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10" Revelation dob
7" home brewed dob |
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Tony Legge
Joined: 13 Oct 2006
Posts: 9
Location: Cambridge, England
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| Posted: Fri Nov 10, 2006 2:41 pm Post subject: |
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| I have no experiecne of a telrad, but I did buy and fit an 8 mw green laser recently as a telescope pointer. I made up the mount, and aligned the laser the telescope aiming at the tip of a power mast about a half mile away. First results are brilliant. On a dark night (not too much moon!) the laser beam is a thin green bar extending into the heavens and it is easy to move the Dobson until you hit the right spot. So far my objects always appear in the finder scope after pointing with the laser. If you look under 'collimation' on our pages, one recommended for collimation advice shows a Dobson with a laser fitted as I have copied. A caution - keep the laser above 5 centigrade or it goes dim (use a muffler to insulate) and take care with your eyes and the eyes of others at a distance. These lasers can be expensive, but 8 mw ones (safer than the higher powered examples on sale there) can be got on ebay quite reasonably. Tony Legge |
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G4LED
Joined: 24 Nov 2006
Posts: 24
Location: Holmfirth UK
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| Posted: Wed Dec 06, 2006 10:12 am Post subject: |
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I use the US made Orion dobsonian and found it almost impossible to star jump accurately by sighting along the OTA. In desperation I affixed an Astro Engineering Red Dot Easy-AimReflex Finder at the front top of the tube. Open eyed viewing is easier and the compact device has far less bulk than the plastic Telrad. Important in my relatively dark situation where clumsy elbows knock things. When mounted (using the self-adhesive pads) in this position it is just a small body movement to move the eye straight to the main eyepiece. The finder scope is now fitted with a diagonal. This allows me to effect manual tracking whilst a guest viewer uses the main eyepiece. If there is any criticism of the reflex finder then it is the red dot being a little bright on even the minimum potentiometer setting. No matter, when out of warranty I will add a suitable series resistor.
G4LED
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"Holme Valley Weather" Davis Vantage Pro+ station; XT10 Orion Intelliscope(frontspiece) |
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