Replace Easy finder II with Telrad

[Brycepj (Peter)]

hey guys I have ordered the bintel 9x 50 finder-scope and the telrad. cost about$200 so that pretty good.
Suzy grab and go table top dob looks good does it require collmination like the larger dob..?
Doogs 38 what did you use for counterweight ? did it take much? piece of led maybe?? attachment hints please
Well done guys thanks for helping me spend my money

[Doogs38 (Alex)]

Hi Peter and well done :-) Regarding weights, I use those small hand held weights that runners carry - I think they're about 1kg each (but I'm not sure?). I attach them with panduit cable ties Alex

[AG Hybrid (Adrian)]

Should have got one of these > Link <

Small. Light. Already raised. Attaches to your OTA via double sided tape. Comes with 2 bases with enough tape, so you can use it on 2 scopes or 2 positions. Has a fade in and fade out feature of the illuminated reticle.

I ditched my telrad and raised base for it.

[Brycepj (Peter)]

I did consider this type of RdF how ever I like the tele ad for the bullseye and the sleeker look.... hope I've got it right time will tell if not I always have the illuminated finder which will match the illuminated eye piece I have
thanks for your opinion

[Suzy]

Originally Posted by Doogs38

Hi Peter. I'm not an expert by any means, but I'll share my experience. First up, I don't own a RDF but have used one, albeit one of the cheap variety and the main distraction for me was the minimum brightness of the 'dot' was still too bright. That said, the view through the glass window was fine.

After many nights of trawling the web, I convinced myself that a Telrad was the way to go. It's ubiquitous, can be dimmed to almost nothing, has accessories, mounts easily with double sided tape, sips batteries at a *very* slow rate, has multiple target rings, is catered for by most astronomy programs and is a star hopping king. It 'just works' exceptionally well for its intended purpose. The downsides are its weight, its length and how easily it dews up. I countered the Telrad's weight with counterweights on the bottom of my mirror box, and built a simple dew cover from black felt that sits over the top of the combining glass. I also use a 2 inch Telrad 'riser' that makes looking through it far easier ... previously I had to put my cheek on the secondary cage but with the riser, I just move my head from the eyepiece/finder and look through the Telrad - no kinked neck

But as much as I loved the Telrad, it just wasn't enough. I complemented the Telrad with an Orion RACI finder and am as happy as a porkine in you-know-what The combo of the Telrad and RACI finder is like having two levels of zoom before using the eyepiece. The Telrad gets me in rough proximity to a target, then the finder lets me see targets to around mag 8.0-ish (from my yard on a dark moonless night), then it's to the eyepiece for the final bit of hunting/scanning.

I recently broke my Telrad's combining glass and lived without a Telrad for two weeks .... aarrggghhhh the pain!! Once you get used to having one, there's no going back

Alex, oh my gosh, that is truly awesome with what you've done with that Telrad, well done you!!!

[Doogs38 (Alex)]

Hah, yes Suzy it's pretty cool and makes using the Telrad even more comfortable I didn't know Telrad risers existed until recently ... I bought one the moment I saw it advertised here:

http://www.telescopes-astronomy.com....ccessories.htm

Alex

[Suzy]

Originally Posted by Brycepj

hey guys I have ordered the bintel 9x 50 finder-scope and the telrad. cost about$200 so that pretty good.
Suzy grab and go table top dob looks good does it require collmination like the larger dob..?
Doogs 38 what did you use for counterweight ? did it take much? piece of led maybe?? attachment hints please
Well done guys thanks for helping me spend my money

Hi again Peter,
hehe I love spending peoples money, I should be thanking you .

Just be gentle and don't bump it around too much. When you pop it in the car, just keep it secure so it doesn't bump & roll everywhere. I don't know how accurate this is, but I was told that solid tubes hold their colimation well compared to collapsibles and also the smaller the tubes the better it holds which has actually applied to me.
I've had the 4" for 2 years now and I haven't needed to colimate it since I bought it. I only had the 6" for about 6 months and I never needed to do it on that either. And my 10" I've had for 4 years and I've only needed to do it once since I bought it. I guess it also depends on how critical you are with colimation. As long as the planets are sharp to me, I don't worry about having to check it.

Regarding weights, see my pic for what works for me. Under the tube, those square black things are large fish tank magnets! They have a fair weight to them. Not cheap tho- the large one cost $50 (it was a spare I had laying around after I sold my other tank). I've got cloth under the one that scours so it doesn't scratch my tube. They're positioned on the opposite side where the eyepiece & finderscope are to offset them (my eyepieces alone weigh around 420g & up). I've replaced the tension rollers that the tube sits on with two teflon rocker box thingies on each side. I've still got the tension handle attached if I want to add a bit more tension, and I've put teflon pads on the base. So the dob is as smooth as butter- but a bit too smooth in alti so that's why the weights are there. Also drilled holes and moved the dob down a bit so it sits a bit lower to the base so it's less top heavy with all that stuff on it. Also attached a black knob at the front of the scope so I can move it easier (I love this!). Hubby did all this work, not me.

[Suzy]

Thanks Alex, I took a look at that link.

[Brycepj (Peter)]

Alex did you get the 2" or the 4"?
Suzy thanks for the advice on the weights will have to try a few things out regarding this trial and error I suppose.
your colmination experiences is interesting I coil ate my solid tube before every session only takes a few minutes. bit if a perfectionist when it comes to this stuff. At present working on an adjustable leveling stand coz I live on a slope also lookng to find exact true north

[Doogs38 (Alex)]

Peter, I have the 2" riser.

[raymo]

Hi Suzy, I don't want to hijack the thread, but it is just not true that
solid tubes hold collimation better than collapsible ones; with truss
tubes it can apply, but definitely not with the SW Flex Dobs. They are
seriously rigid. In fact, my 10" Flex requires tweaking less often than my 8" solid Newt.
raymo

[barx1963 (Malcolm)]

And with care, trusses work really well. With my 20" all the trusses are numbered so they are set up in the same order each time. I always set ip up in the vertcal position and tighten the knobs in the same order. Usually needs no more adjustment than my old solid tube 12" (and often less!)

My other scope is an 8" travel scope using just 2 square tubes instead of a truss and it also holds collimation very well, only needs a bit of tweaking.

I think it is more the quality of the cell, mirror supports, collimation mechanism and secondary mechanism that affects how well a scope holds collimation rather than the type of design.

Malcolm

Originally Posted by raymo

Hi Suzy, I don't want to hijack the thread, but it is just not true that
solid tubes hold collimation better than collapsible ones; with truss
tubes it can apply, but definitely not with the SW Flex Dobs. They are
seriously rigid. In fact, my 10" Flex requires tweaking less often than my 8" solid Newt.
raymo

[Suzy]

Originally Posted by raymo

Hi Suzy, I don't want to hijack the thread, but it is just not true that
solid tubes hold collimation better than collapsible ones; with truss
tubes it can apply, but definitely not with the SW Flex Dobs. They are
seriously rigid. In fact, my 10" Flex requires tweaking less often than my 8" solid Newt.
raymo

Hi Raymo & Malcolm, thanks for that input. As I said, I didn't know how accurate that information I got told was, so good to know. My friend's collapsible needs constant collimating, so Malcolm you raise a good point regarding how well the mirror is supported.

[AG Hybrid (Adrian)]

Originally Posted by Suzy

Hi Raymo & Malcolm, thanks for that input. As I said, I didn't know how accurate that information I got told was, so good to know. My friend's collapsible needs constant collimating, so Malcolm you raise a good point regarding how well the mirror is supported.

The problem is not the struts. They are not causing collimation shift. It the weak springs in the mirror cell. Upgrade the springs. Get C-702 springs from bunnings. Tighten the collimation screws all the way and throw out the locking screws. Collimate by loosing the screws. I can disassemble my scope, man handle the big ******* into my car, drive 90 kms to a dark site with last few kms a dirt, gravel and corrugated road. Reassemble my scope and check collimation and find that it is only a couple mm off for my secondary and still bang on aligned for my primary mirror.
With upgraded springs collimation is a 30 second job at most.

[Suzy]

Thank you so much for your advice Adrian, I will tell my friend this.

[Brycepj (Peter)]

Adrian
I'm curious about the advice on collimating, throw out the locking screws? On the primary? Why? Up grade the springs? I'm yet to pull any of that apart so a little bit in the dark ( no pun intended). I collimating every time it's always out by say 5mm I get it pretty much spot on when adjusting. What is it that keeps "miss aligning is it the primary or secondary or both? How can I find out? Is it normall for a dob to fall out of alignment every time you use it or move it? if I'm moving it 30 feet on a dolly. I'm am lifting it on and off. (If it is like tuning a guitar however once I tune my D28 it rarely needs retuning after a month of regularly playing - especially when it's a crap night)
Like to know if it's me or that's just the way it is.

[barx1963 (Malcolm)]

Peter
I assume you are talking about your Orion dob? I am not familiar with the collimation setup on these dobs but will answer some of your queries based on experience with others.
Some scopes have adjustment and locking knobs and what I found was I would loosen the locking knobs, then get the collimation just right, then I would tighten up the locking knobs and it would move the collimation! So I was actually collimating twice, once with each set of knobs.
Solution was to chuck the locking knobs and make sure the springs holding the cell were strong enough to ensure that the mirror wouldn't shift as it moved. Easy to test, just collimate then check thah the collimation is still ok while moving the scope through 90deg in alt. I usually test with it vertical, horizontal and at 45deg.
It is nothing unusual for it to need adjusting each time. One thing I found with my old 12" solid tube was that picking it up by the back could throw out the colli a bit. I reduced this by making a set of webbing straps to carry the tube with, easier on th back and made sure I was handling the cell as little as possible.

Malcolm

[Brycepj (Peter)]

Malcolm
Thanks for your reply yes you are correct regarding my dob.Yes it has locking screws I was just surprised at getting rid of them. I fully understand about collmination twice it's a pain I will also look at this minor modification. I assume not hard to do if you do remove and replace one screw at a time.
Another quick question when storing your dob is it in an upright (90degree) position or horizontal? I noticed the park function on the Syn scan is about 45. Degrees. Wonder if this would make a difference at retaining collimation
Thanks

[AG Hybrid (Adrian)]

With improved springs the locking screws become obsolete. Hence why I said you can throw them out. Just make sure you tighten the collimation knobs all the way. Collimate by loosening the knobs. But, generally you only need to adjust 2 knobs at most.