GSO 12" Dob First Light :D

[Jazza (Jay)]

Well the 12" arrived yesterday from Andrews, ordered friday, arrived thursday!
Monday was a public holiday!

Put it all together, not too bad considering the instructions still think they're using a bearing system... put one of the panels on the wrong way around, laughed at myself when the handle on the mount immediately fell off... banged the staples back in, turned the part around and she's all good.

Movement seems pretty smooth, check outside... of course... clouds...
Sorry all you tasmanians for the clouds tonight! My fault I know.

Played around with the cheshire and the laser collimator, adjusted the secondary a tad but left the primary where it is, seems pretty much spot on to me but I may post a snappy at some stage to get some feedback. Looks like TNT take "handle with care" seriously!

Scope is pretty easy to move, man dobs are an easy type to set up!
I think it's quicker than my 6" eq mounted newt!


Found the moon through the clouds and the sight damn near blinded me *sigh* gonna have to purchase a decent moon filter cause I seem to have misplaced my old one.

Pretty blurry but that's the clouds.

Swung her up to orion and found my first bit of difficulty, the right angle finder scope. I'm having difficulty pointing it at the right area of sky! I'm used to a straight through so I can chuck my head behind it and eyeball the patch I wanna aim at, and when I get close voila it appears in the finder. Not so with the right angle... gonna take some getting used to! (Or I'll steal the ifnder of the 6" )

Got her pointing at M42 as it was the one part of sky not obscured and wow!
Considering it was twilight, hazy, the scope wasn't cooled (no batts for the fan..)
I was rather astounded, so much more extended than I've ever seen it before. And possibly a tinge of green? Stared at it for 15 minutes or so till the clouds rolled in.

Man I hope we get a clear night this week-end!

Pointed it at sirius for the fun of it, but no sign of the pup May have something to do with the amount of cloud in the way too mind you...

I'm really looking forward to some dark skies.
(how massive are the 2" eyepieces!!!)

Jay

[markus.a.bergh]

I have also recently bought one of these. It's amazing.

[mrsnipey]

Hi Jazza,
Try putting the lid back on the 12" and taking the little cap off the lid.
Then look at the moon. It will still be too bright but it's bearable.

[Starkler (Geoff)]

Originally Posted by Jazza

Scope is pretty easy to move, man dobs are an easy type to set up!
I think it's quicker than my 6" eq mounted newt!

I believe you. These dobs are total simplicity and surely the best bang for the buck out there. When I take my 10" dob out I can unload it from the car and be ready to view 5 minutes after turning up.

Found the moon through the clouds and the sight damn near blinded me *sigh* gonna have to purchase a decent moon filter cause I seem to have misplaced my old one.

Nah just use high magnification. How much time do you spend viewing the moon at low mag? Throwing away light I think lessens the ability to see fine detail and with the moon out your not going to be concerned about dark adaptation anyway.

the right angle finder scope. I'm having difficulty pointing it at the right area of sky! I'm used to a straight through so I can chuck my head behind it and eyeball the patch I wanna aim at, and when I get close voila it appears in the finder. Not so with the right angle... gonna take some getting used to! (Or I'll steal the ifnder of the 6" )

This is where a Rigel quickfinder or a telrad comes in handy as a sighting tool.
Some people throw away the optical finder and use one of these, but I prefer to have both. The right angle finder does save your neck and back and you will come to appreciate it.

Pointed it at sirius for the fun of it, but no sign of the pup May have something to do with the amount of cloud in the way too mind you...

Might also have something to do with the seeing and also not having your fan running. The fan will make a big difference in cooling your mirror and allowing it to give you best possible views.

Congrats on your new scope

[Jazza (Jay)]

Thank you people for the advice people will definitely have a look at the moon while its full (or near full) cause it's glowing out the sky at the moment anyway
Yeah, I'm considering a telrad/quickfinder at some stage...

One quick question, do most of you leave the fan on all night or just run it for the first hour or so?

Jay

Oh and grats to you too markus

[erick (Eric)]

Originally Posted by Jazza

One quick question, do most of you leave the fan on all night or just run it for the first hour or so?

Jazza, what I read suggests that a couple of hours of fan is all you need to get the mirror temperature sufficiently close to ambient for the "less-than-really-fussy" observer, but I guess that depends on how far the temperature is dropping as the evening deepens.

For a solid tube OTA, many suggest leaving the fan as an aid in preventing dew formation on the primary and secondary mirrors. As long as the fan is not giving you unacceptable vibration of the image (easily checked) and you have the power supply, you may benefit from leaving it on (cooling plus dew reduction). Fan life (measured in observing sessions) would be reduced, but probably it'll outlive your ownership of the scope! The only other issues then are power supply and not getting tangled up in the wires.

[omnivorr]

..I've wondered bout this fan business..does the fan just blow on the back of the mirror.. or does any go up the tube?? .. since the whole issue seems to be about avoiding convection-current derived air-movement in front of the mirror ( &/or difraction at the interface of differing density air-layers).... wouldn't it defeat the purpose to have fan-turbulence introduced ?

[erick (Eric)]

Hi omnivorr

I bought Scott Tannehill's 12" and he had done some work on the fan and airflow path. Here are his views here:-

http://www.iceinspace.com.au/index.p...63,400,0,0,1,0

[omnivorr]

thanks erick ..not a star in sight.. need a good read!! ..so much good stuff here, but as a recent blow-in, dunno where to look.. the library's full, but the librarian's "out to lunch"