Easy way to tell where a dob is pointing?

[Tim]

I'm hoping to learn where a lot of stuff is in the sky without the benefit of the GOTO I have been using for years. However, I also dont wish to spend half a night trying to find something....

A very experienced observer I know has some gauges on his large dob that tell him where it is pointing, as an aid to tracking down very faint stuff.

I think they have some kind of encoders at work.

I have acquired a used David Lukehurst dob and am wondering if there is a simplish, cheapish way to add something on that will make it easier to be accurately on the mark. My home skies are very light polluted, so a bit of a headstart would be useful!

Thanks

Tim

[Stu]

Tim, the cheapest way is to put a degree type circle on the base to show the Azimuth direction, and then a device called a Wixey on the scope itself to give you an Altitude reading. You still need to read off the results on a planetarium program but it can work.

The best option in my mind, although much more expensive, is to fit encoders (as you mentioned), with a device called a Nexus from AstroDevices. This creates a wifi connection and allows you to connect a smartphone or tablet to the Nexus which sends out the co-ordinate data to SkySafari. Once calibrated this will show the correct position of your scope on the star map, and also allow you to select an object and receive pointers as to which way to move the scope to get to the target.

http://www.astrodevices.com/products/Nexus/Nexus.html

It's a very elegant solution which works beautifully. The hardest part will be finding a suitable encoder kit and fitting them to the scope. David Lukehurst may well be able to advise you.

[Tinker1947]

I have a Telrad, if you know some stars ect, there easy to spot looking through it........

[niallk]

Hi Tim, as already suggested, for several years I used Telrad and SkySafari on my phone to find things, switching over then to 9*50 finder then the eyepiece to locate things. Worked well, did require a little patience, but also very rewarding when you find new targets.

This year, I switched to Argo Navis 'push to' when I got a new scope, and it is fantastic. The Nexus system as suggested sounds really good - I hadn't considered it when I got AN, but it really looks great.

By the way - what size DL dob did you get? Congrats & enjoy!

[Tinker1947]

I had a SGL member pop round with his Dob, and a Nexus system in its box, took 10 minutes to just a few nuts and washers nothing else, if i had another to do, 5 minutes thats with a tea break, in use it's really good certainly something i would go for if i didn't have a GoTo..

[Tim]

Thats very useful, thank you. The scope has a telrad on, but tbh I dont want to be finding things, I want to be looking at things

The scope is an 18" f4 Niall. I just got it second hand from a friend. One day I plan to build my own exactly as I want it, but thought this mid sized dob would be a good intro and a way to find out what is really important to me. We did have a Skywatcher 300 truss dob before, but I couldnt put it away on my own, so it went to somebody else. This one has wheelbarrow handles and drops into my conservatory quite easily at the end of the night.

[jabeoo1]

It's a very elegant solution which works beautifully. The hardest part will be finding a suitable encoder kit and fitting them to the scope. David Lukehurst may well be able to advise you.

Indeed, When David build my scope it was an optional extra,  however I did not opt for this feature.  I was told they can be added afterwards if i changed my mind, he is certainly an excellent person to talk to about technical advice on this matter.  

[niallk]

An 18" f4 Lukehurst dob sounds really sweet! Is it his classic or one of his ultra light types? I have been a frequent visitor to his website.

I do have to admit that while Push-To does feel like cheating to me, I do enjoy seeing more targets, and taking my time to study things. I find I now put more effort into planning up front. I went to my first star party a week ago, and what immediately struck me was the sea of red lights from all the Go-To handsets! I didn't feel too bad turning on the AN unit

[estwing]

I'm a big fan of charts and a telrad..basic it might be but the hunt is part of the process, frustrating at times but its all part of the learning curve. Faulksy has the best push to system I've seen..he's your man to speak to....oh and welcome to the Dob mob, that 18" will give you fantastic views..clear skies.

[Charic]

I'm a long way off from any GoTo or PuTo, preferring the simple approach, aim and look.

You don't even need a finder scope if the eyepiece has a long focal length, just rotate the Dob until under your target, then raise the Dob onto the target. If Im after something in particular, I will refer to Stellarium. I configure Stellarium to replicate the visible Stars, and work from there.

I think GoTo or PuTo is a good idea for groups as they can, at will, select any target from the database, and providing that everything is configured, correctly, and the targets are available in your sky and the seeing is good, what better way to spend night out with the scope, and a few friends.