8" Skyliner dob

[KevUU]

So. It's clear I need a Telrad or Rigel, the finder works okay but sighting along it is horrible and uncomfortable.

I also need a RA or RACI finder. I still harbour this idea of using my ST80 for it, if I can think of an easy and lightweight way to attach it. Any suggestions / advice / warnings?

[Stargazer_00]

The ST80 would be too heavy, by far. A Telrad and RACI is a good combo and one I'm going to try myself in the future. I currently favor a straight through finder and have a TelRad sitting in a box in my astro cupboard unused.

I wouldn't advise using a RA or RACI without some sort of zero point finder (Telrad Rigel) or a straight through. I'm toying with the idea of putting a 6x30 straight through on top of a RACI somehow. I dont like things that use power...I dont want to fix to finder shoes to the scope either. The 6x30 would serve well enough to centre a start star and then just move to the RACI and hop.

[KevUU]

I can't find a weight for RACI, but if I assume 200g then I get:

Telrad + RACI + 2" EP = 950g

Rigel + ST80 = 1600g

So a bit more but not bonkers, probably balanceable with a small weight?

But I expect you're right I should leave it, just seems like a neat solution and now I've got it nagging in my head...

[Stargazer_00]

I'd sooner leave additional weight on that end to stonking huge eyepieces rather than a finderscope that used just to locate targets not view them. A finder setup should serve two purposes; 1: assist you to find a target and 2: not kill your back in the process.

Putting the ST80 on the dob would need balancing. It'd also tie up what is a great grab and go scope. It doesnt have a cross hair and it could possibly be difficult to get it in the right alignment to serve as a finderscope rather than jut a piggy back telescope.

For me, using a dob, anything on the nose end that isnt directly related to viewing should be as light an unobtrusive as possible. This leaves you more real estate to play with at the eyepiece in terms of weight and size.

[cotterless45]

Just stick a Telrad on there, get a funny foam sheet to make a dew shield and use the friendly download charts.

I still can't get used to finder scopes, corrected or otherwise.what really helps

is clear skies

Nick.

[AstroTux]

Kev,

had a play with Linda's Nephew's new 8" Skyliner Dob ( same as yours ) last weekend and found it rather good. The only thing I would do to modify it would be to put a Rigel Quickfinder next to the finder 'scope. They are a similar cost to the Telrad but a lot less bulky, so wouldn't upset the balance much.

I thought the finder 'scope was good but found its magnification confusing when trying to locate an object by naked eye stars. There was just too much to look at that I didn't recognise!!! :grin: At least with a Quickfinder you can get the 'scope pointed in roughly the right place first, and then use the finder 'scope to narrow down on the target.

I have to say that the views we had of Saturn were stunning ( Cassini division, belts and shadow of the rings were all clearly visible ) and I managed to get a relatively good view of M3 as well. We also checked some of the regular targets such as M35, 36, 37 & 38 and the results were very pleasing. I think you'll end up being rather chuffed with your investment.

We've just started the 10" dob fund, so hopefully will have the filthy lucre to buy one of these at some time soon.

Hope this helps,

Alan

[KevUU]

You are, of course, both right.

I do need something powered as well as the Telrad though, I could never have got to M35 without star hopping in the finder. But the straight through is already cricking my neck, and I have a real pain in the ... top of leg joint ... the last few days which I half think may be related too.

What are people's opinions on Telrad vs Rigel? I've seen That Comparison which doesn't seem very conclusive; Rigel is lighter is all, 310g vs 75g.

[KevUU]

Thanks Alan - always good to have an answer 4 minutes before you ask the question (I think we cross-posted)

I do like it rather a lot already, I can't imagine you'll regret the 10" when you get it

The finder is just a pain to look through, literally, when looking towards the top half of the sky. Otherwise it seems a nice finder.

Are you going toSalisbury later in the year?

[AstroTux]

Having tried both I prefer the Rigel as it is smaller and lighter and puts less strain on the 'scope or person pushing the 'scope around. The Telrad is BIG and this is mainly due to the size of the battery compartment. Someone has recently posted about modifying their Telrad by removing it ( I think it under DIY astronomer ). Both do a similar job and the Telrad is marginally better when it comes to parallax errors, but I find the Rigel very useable.

We're looking at going to Salisbury but haven't decided yet. Will let you know the outcome of our decision when we've made it.

all the best,

Alan

[rory]

you might get away with the straight through for now ,by simply using a telrad/rigel combined with your lowest power e/p , you can usually get what you want to find that way, with the optical finder for a fallback.

i have a raci finderscope and its comfortable to use ,but i find i rarely need it . my 31mm eyepiece and telrad will usually get me where i want to be .

oh , and on the telrad/rigel debate, they are both well regarded kev. id suggest the telrad option is better if you add a riser plate either 2" or 4" , of course this adds to the cost though. i use a 4" riser.

[KevUU]

Thanks both, I'll have a ponder

rory, glad to see you're still with us

i have a raci finderscope and its comfortable to use ,but i find i rarely need it . my 31mm eyepiece and telrad will usually get me where i want to be .

I have a feeling this is the first time I've used the finder to star hop ever, so I agree with you mostly. But I did need it for M35, was seeing too much too close in with my 30mm to navigate from PSA, and couldn't see anything naked eye... I think I'll end up with what you have, a rarely used RACI.

[rory]

" rory, glad to see you're still with us "

ta, kev. hopefully out tonight and see if the leo trio present themself ,if so ill try out some of virgo as ive only had a brief encounter in that soup of galaxies.

jury is still out as to weather to sell up, but while its here i gotta try eh .

happy hunting ...

[KevUU]

I wouldn't mind a bit of Leo or Virgo soon, too

If I were you I'd keep the kit, and make a conscious effort to not 'care' as much for a bit, and just let yourself find a natural level: either you'll be twitching at the curtains and planning in your head, or you'll get to clear nights in Autumn and find yourself uninterested; either way you'll have your answer without wracking it over in your brain now and then regretting a rushed decision.

Of course if I were you we'd both have serious problems, so make of that what you will!

[KevUU]

£65 for a RACI? Now I remember why I wanted to use the ST80 instead

[tibbz2]

I really need to save up for a RACI now, the straight through finder is doing my neck in.... They're pricey like you say though!

[Stargazer_00]

The thing with replacing a straight through (if that is your only finder) with a RACI is you have no way to point at stars by eye. A RACI needs to be accompanied by a Telrad or a Rigel or alongside a straight through so it isnt just the cost of the RACI you need to find but the accompanying finder element that gets you on the first star which you then use the RACI to hop from.

What would be perfect (for me anyway) would be a straight through 8x50 that you could adjust the eyepiece end to twist at 90 degrees and become a RACI once you have located a guide star. I dont like the idea that when I get a RACI next month that I'm going to need to use the Telrad (which I already have). I just dont like things that use power much. I think I'm going to come up with a way to keep a straight through and RACI on the scope together. I'll probably sell the Telrad at that point.

[colesmat]

This has turned into a great thread kev. I've got the same scope and struggled with the finder (like everyone does). Mainly because you see 10 times as many stars through it than with the naked eye, very confusing! Anyway, you're asking all the right questions so I'll keep reading!

Matt.

[KevUU]

Cheers Matt. I use the finder alongside my Pocket Sky Atlas so I find I can see just the right number of stars, but getting my head into position is troublesome, especially since I wear glasses. More questions to follow soon

[KevUU]

Okay, I've ordered a Rigel QuikFinder (and a UHC filter while I was at it )

Now, eyepieces.

I have 8mm and 30mm Vixen NPLs, which have been great in the ST80.

Now in the 8" they are noticeably far apart, giving me x40 and x150. Also the 8mm seems uncomfortable with a narrow front eye lens, I just don't feel comfortable using it somehow.

I'm not sure on the quality of the stock SW barlow that came with my ST80, but also I just find it detracts to add the barlow to the eyepiece change process.

So, where do I start?

1. Sizes

I was thinking something around 12mm would be good, giving me x100. I may also replace the 8mm with a better design. I've been told that anything over 25mm in the 200p will just show lp, and I think I'm seeing that in my 30mm, but I'm not in any rush to fix that yet.

2. Makes

BST StarGuiders come highly recommended, so I think I'll give at least one of those a go. Of course a 2/h Hyperion would be great, but I could do with settling on my sizes before I look at those!

What do you think? What makes/sizes do others recommend, 200p owners especially? What sort of mag range have people settled on?

Thanks,

Kev

[Mr Fiery Jack]

Very personal things EPs'. I find my own set cover every angle for me with a 10 inch dob. If I am honest I could probably do without the 32mm and 19mm.

[tibbz2]

The thing with replacing a straight through (if that is your only finder) with a RACI is you have no way to point at stars by eye. A RACI needs to be accompanied by a Telrad or a Rigel or alongside a straight through so it isnt just the cost of the RACI you need to find but the accompanying finder element that gets you on the first star which you then use the RACI to hop from.

What would be perfect (for me anyway) would be a straight through 8x50 that you could adjust the eyepiece end to twist at 90 degrees and become a RACI once you have located a guide star. I dont like the idea that when I get a RACI next month that I'm going to need to use the Telrad (which I already have). I just dont like things that use power much. I think I'm going to come up with a way to keep a straight through and RACI on the scope together. I'll probably sell the Telrad at that point.

I have a Telrad which is why I want one now!

[KevUU]

Very personal things EPs'. I find my own set cover every angle for me with a 10 inch dob. If I am honest I could probably do without the 32mm and 19mm.

Cheers Fiery Jack. That would tie in with other advice I've heard, 25mm 12mm and 8mm, and barlow the 12mm on the occasional times I want to try 6mm.

A 25mm BST would give me x48, 1.25* fov.

My 30mm Vixen NPL gives x40, 1.25* fov.

So on the face of it there would seem to be little advantage to changing, but do I remember someone suggesting the contrast would be significantly better in the 25? Not sure I understand why, if so?

Decisions, decisions...

[Stargazer_00]

The magnification is higher so the background is darker, boosts constrats. Also the 25mm BST would have more AFOV than the NPL, and that is more pleasing to the eye

[KevUU]

I bought the 12mm BST, and really like it - see my review here.

My next question, following on from that:

I've heard tell that 8mm is about the limit for the 200p, although I've had some luck with 6mm (12mm barlowed) and would like a dedicated ep at that sort of length. However, I see there is no 6mm BST.

? Can anyone suggest whether 5mm (x240) would be usable, or should I not bother trying?

? Or, can anyone suggest a good 6mm that would be comparable to the BSTs in comfort and ease of use?

Thanks

[KevUU]

Just looking back through this thread, I'd forgotten how much discussion there had been on finders, the straight-through vs RA/RACI vs Telrad/Rigel. So I thought I'd give my experience now that I have some.

The problem with the straight-through 9x50 was the need to sight along it to get a reference star lined up to start with. This was an uncomfortable neck-cricking wet knee experience!

The Rigel has totally solved that issue, I can peer from vaguely behind the rigel to get pointed in the right direction then peer from vaguely behind the finder to get a better alignment, then often go straight to my 12mm ep from there. I can do it all from the same seated position that I observe from. I haven't even considered a RA or RACI, and still don't intend to.

I hope that may be of some use (if anyone's still reading this old thread)