new 8 inch dobsonian

[Chippy3476]

Hi all,
I have just ordered an 8 inch dobsonian :D I am so excited now!!!! This is a big step up from my 114 newt I think. so it has a 2 inch focuser so I was wandering if I was to get a eyepiece adapter for my 1.25" eyepieces would these still give as good a view as a 2" eyepiece???
Thanks all
Dan

[madwayne]

Congrats on the purchase Dan. Your shiny new dob should come with a 2" to. 1.25" adaptor. The views through 1.25" eyepieces will be fine. My preferred eyepiece in my 12" is a 16mm Nagler and it is a 1.25" barrel.

Enjoy the views and take your time if you miss something this year it will be back same time next year.

Wayne

[barx1963]

Congrats Dan!!:thumbsup::thumbsup:

What model did you end up getting? With eyepieces, it will probably come with some anyway and should have an adaptor as Wayne said.

Malcolm

[Chippy3476]

I went with a saxon, i have always wanted one of them so I finally decided to just get it, with the wifes blessing of course :lol:

[Chippy3476]

What would be the highest practical zoom on this scope? What sort of things can I expect to see clearly? I cant wait to get out there and use it!!
Thanks
Dan

[N1]

The optics being good, the highest useful power is around 2x the aperture in mm, i.e. 2x200mm gives 400x, give or take. HOWEVER, this assumes next to perfect viewing conditions, which happen next to never :sadeyes: for most people. Highest practical magnification will be anywhere between 150x and 300x most nights and depending on your locality. For most targets, that's plenty of power. In fact, a lot of deep sky objects will require far less as they are quite large. The 8" will show an estimated 90-95 per cent of all objects & features being discussed in the "visual" sections of this forum :P :thumbsup:.

[Renato1]

Your 2" focuser will come with the adapter for your 1.25" eyepieces.

Basically, for most typical eyepieces of focal length 18mm or smaller, they will show all that can be shown in 1.25" barrel size (except for the expensive 100 degree Field of view ones).

2" eyepieces are good because they will show bigger fields of view when you have 20mm or bigger ultrawide angle eyepieces, or 40mm super wide angle eyepieces. People like the bigger fields of view, because they're nice, and they are good when they frame a really big deep sky object into the entire field.
Regards,
Renato

[John0z]

Generally maximum magnification is 50x inches of aperture, so about 400x is max. However most of the time you will be using much less - i.e. 30-40mm eyepiece will give a nice full view of the moon without having to move around too much, then going to smaller eyepieces and/or barlow will give you closeups.

[Steffen]

The highest practical magnification depends largely on what you're observing, your ability to nudge the Dob along, and your determination.

Objects move through the field of view very quickly at high magnifications, especially near the celestial equator, so you need to hone your manual tracking skills.

Seeing is never bad all the time, only most of the time. When looking at sub-arcsecond double stars (which a good 8" scope is perfectly able to split), you will need more than 400x, sometimes a lot more, and also a lot of patience. Views at high magnifications are limited by seeing most of the time, but there is the odd second out of ten (or thirty, or more) every now and then where the view stabilises and reveals what you're after. That counts as a success, once you've seen a double split it cannot be taken away from you :)

But as I said, this takes skill and perseverance, so for starters you're probably more comfortable with the 150x and lower magnification range.

Cheers
Steffen.

[Chippy3476]

Another question I have is, would this scope be good with binoviewers? I was going to get some for my 114 newt but was told that the scope wasnt big enough, so would 8" be good or still not worth the money?
Thanks

[raymo]

I would suggest trying to find someone who has a binoviewer set up on a similar size scope ,and try it out. A decent bino and pairs of decent EPs
would cost pretty much what the scope did.
raymo

[Starlite]

Hi Chippy, If I can get over to the Nth side I'll bring some binoviewers with me.You really need to check them at night at infinity on a star because getting focus on a tree during the day can trick you into thinking you have enough forward travel. You will enjoy bino viewing and the kids find it easier with 2 eyes also. My Denkmeiers will blow you away, they have a 3 way power switching system. 1st stage is "that's great" 2nd stage is "holy $@#@" 3rd stage "You have to be joking". Pic shows plenty of forward travel to go after focusing on Fomalhaut tonight. .:):) Great for viewing the moon at any stage as you don't need a moon filter, as the binos darken the incoming light by 10-20% so no welding flashes. :eyepop::eyepop:. edit, pic is with Williams Binoviewer on 8" Skywatcher Dob.