Telrad Guide

[brianmc]

I got out last night to try out my new Skywatcher 7-21mm zoom eyepiece on my 200p. I got good views of Jupiter and was satisfied with it overall. However the field of view is a drawback. I certainly don't understand everything about FOV yet but having used the 7-21mm (which I believe has an FOV of 30-43 degrees) I,m now thinking of a 5mm BST Explorer with 60 degree field of view so that I can get close up on Jupiter for more than what felt like 5 seconds. Further on I'd like some sort of 2 inch wide angle low power piece but they seem like they need a lot of saving up for.

I still haven't had a chance to view the moon so I'm now looking for other objects to observe. The difficulty I think I'm going to have is picking out a particular object. My google sky map isn't accurate enough to point me at more than the brightest and most obvious objects. I've read about the Telrad but can't seem to find a really detailed description of how you use it. Can anyone recommend a guide? Can anyone suggest a good object that would be easy to find, preferably high to the south before midnight? It would be nice to see a double star perhaps that only resolves in the telescope.

[Astro Imp]

Hi Brian,

For an introduction to the Telrad have a look here.

FWIW I have been using a telrad since just after getting my scope and found it a great help.

HTH

[BAZ Senior]

A Telrad is a non magnifying finder, what it does is project a series of LED generated rings onto a glass screen similar to a head up display in an aircraft. This allows you to look through the glass, and see the rings "in" the sky in half, two and four degree circles.

This gets you close to the object you are looking for, but you will still need your star map and magnified finder to home in on the target.

Here's a useful link that should make things a bit easier.

MSAS: Messier Finder Charts

[umadog]

Go through the articles here for eyepiece advice: Tele Vue Optics: Advice

Chuck Google sky map and buy yourself the Sky and Telescope Pocket Atlas and a *dim* red light (use red nail polish if it's too bright).

There are masses of pretty double stars and open clusters in Cassiopeia, so spend some time there. For example, there are two pretty colour doubles in the region between epsilon Cas and NGC 637. Annoyingly those aren't listed as being doubles on a lot of charts (even good ones like SkyAtlas 2000) but they show up in Stellarium as

HIP 8626 and HIP 8262. There's a double in M103, which is really easy to find as it's next to delta Cas. Eta Cas is a nice colour double. NGC 7789, just off beta Cas, is a lovely open cluster known as the White Rose. Between Cas and Perseus is the famous and splendid double cluster. Just south of Cas is out splendid neighbouring galaxy, M31, with its two satellite galaxies, M32 and M110. That lot will probably keep you busy all night.

You could do a lot worse than buying Turn Left at Orion, which is a nice guidebook for the beginner.

[brianmc]

Thanks all, finger crossed for clear skies tonight.

[pritc]

I have a Telrad finder on my 200P. Easy to use and I highly recommend it for star hopping and locating objects.

I use a 2" SW 32mm Panaview with my 200P.It is a great wide angle low power eyepiece.

I take it you have the standard un-driven EQ5 mount as you say Jupiter only stays in your FOV for 5 seconds?

It did not take me long before I upgraded and got the EQ5 DC motor drives.

If you have access to a laptop whilst viewing.

Stellarium is a great free planetarium program.

I certainly learnt my way around the night sky using it.

Wayne

[Telrad]

brianmc, try these online Telrad charts posted at these sites:

Sky Maps

Messier Maps

Try these links too:

Caldwell Object TelRad Charts

Messier Object TelRad Charts

That will get you started.

Excellent choice btw

[brianmc]

I've got a Dobsonian mount not an EQ. Having spent some more time searching these forums last night I'm now leaning towards this method: http://stargazerslounge.com/diy-astronomer/80995-diy-dob-setting-circles.html. I've downloaded Stellarium so this seems a simple way to point directly at my target, probably with as low power an eyepiece as I can get to allow some margin for error.

Also the Wixey might allow me to put up the first level shelf of my life.

[rory]

that looks a simple but good idea. like some of the posters say, wonder why they dont come with a base setting circles already on there ? keep costs down i suppose .

[twotter]

Before you go and buy more bits and pieces try using Stellarium, it's a free download after all Stellarium and your local library may have a copy of Turn Left at Orion. I use both and you may find using a low power eyepiece will help. My first extra eyepiece was a 32mm plossl and it certainly helped me to find my targets.

I understand field of view (FOV) to be the area of sky I can see through the eyepiece, given in degrees. Different types of eyepiece give different FOV. There are lots of brands but here are a few I know of:

Baader Genuine Orthoscopic = 40 degrees

GSO Reveleation Plossl = 52 degrees

BST Explorer = 60 degrees

Baader Hyperion = 68 degrees

Willian Optics SWAN = 72 degrees

Televue Nagler = 82 degrees

Televue Ethos = 100 degrees

Zoom eyepieces are a compromise and in cheaper ones it is the FOV that suffers. My 8-24mm goes from 40 degrees at 8mm up to 60 degrees at 24mm. That feels very narrow if I use it after looking through my Hyperions, but that's the price I pay for the convenience of using a single eyepiece.

[John]

One of the slightly annoying features of many zooms is that they provide a reasonable 60 degrees field of view at their shortest focal length but that narrows to 40 degrees or so at their longer end. Exactly the opposite of what you would want of course !.

Personally I can cope with a relatively narrow field of view when viewing at high powers but I do like the "wide open vistas" at lower powers.

Eyepiece preferences are very personal though.

[brianmc]

I have got Stellarium and Turn Left at Orion but when going from looking at the sky with my naked eye to looking through the finder scope to looking through the main scope, what you see is so different that I'm not confident that I'm actually looking at what I want to. This isn't a problem with bright objects but with dimmer ones I need some help. Hence my thoughts about a Telrad and now setting circles and angle finders.

[Dil]

Is anyone else here finding it difficult to buy a Telrad? All the online shops say they are unavailable. Is the Rigel Finder as good/better than the Telrad?

[Telrad]

Is anyone else here finding it difficult to buy a Telrad? All the online shops say they are unavailable. Is the Rigel Finder as good/better than the Telrad?

For me Telrad's slightly more expensive but have larger switches and are easier to turn on; although heavier this might upset an overall balance for some users. The reticle is nearer to the OTA, but still easy to peep through. Blinking reticle optional. They're more robust in attaching and detaching. Telrad has one more large 4 degree circle and use AA batteries, plus they're a better build. IMHO

　

[kharga]

Also try Astronomy Now - The Night Sky This Week

and Skymaps.com - Publication Quality Sky Maps & Star Charts which lets you download and print out this http://skymaps.com/skymaps/tesmn1111.pdf every month.

Telrads here Telrad Red Dot Finder

[twotter]

I have got Stellarium and Turn Left at Orion but when going from looking at the sky with my naked eye to looking through the finder scope to looking through the main scope, what you see is so different that I'm not confident that I'm actually looking at what I want to. This isn't a problem with bright objects but with dimmer ones I need some help. Hence my thoughts about a Telrad and now setting circles and angle finders.

I know what you mean. The finderscope really confused me, so much so that I removed mine and use a simple red dot finder in it's place. Stellarium allows you to adjust the settings so it replicates your own skies, sort of dialling in your local light pollution as it were. I've found that helpful.

Good luck with whatever method you choose

[umadog]

Yeah, finders are a pain. Right angle ones probably more so. Even a red-dot sight will work better. It doesn't have to be a Telrad.