New 10" Dob

DJVege · #1 21-01-2008, 08:53 AM

Hey guys,

Seeing as the weekly (if not monthly) forecast was for cloudy weather, I figured I probably wouldn't hurt anyone's seeing by getting some new equipment!

So, I am now the proud owner of a brand new (2nd hand

) 10" GSO Dob! Sure is bigger than I imagined it would be. Makes my 5" look like a baby!!

My question is, "Can I mount this on my HEQ5"? I read somewhere that a good limit on the HEQ5 was 15kg, and the 10" OTA weighs around 13Kg...without EPs or the finder. Would I be overloading the mount?

Not a biggy, because I'll be using the 10" as a visual scope for now, but just wondering about upgrades...

§AB · #2 21-01-2008, 08:58 AM

congratulations dude, you'll love it

When I first saw mine, it's size surprised me aswell!

Btw, the tube is actually closer to 16kg "clean".

rmcpb (Rob) · #3 21-01-2008, 10:09 AM

Congrats on the "new" scope.

As for the mount, the HEQ5 would be marginal for visual but work. Forget about any serious astrophotography on it though except for some lunar stuff possibly.

Now the wait for some clear weather

DJVege · #4 21-01-2008, 02:17 PM

Ok. Thanks guys.

I have one more question, though. Supposedly coma is apparent in these scopes. Besides a paracorr, is there a way to decrease the amount of coma in a scope? Not a real biggy, though.

Also, in my 5" scope, there are little "ripple-like" ridges inside the scope,about halfway down. What are they for? My 10" doesn't have them...

Thanks!

§AB · #5 21-01-2008, 02:24 PM

^^ at F/5, coma does become a problem. For example, using my TV 32mm plossl in my scope is like looking out the window of the "Enterprise" at warp speed

You can always buy high end eyepieces, such as Naglars, Panoptics and Vixen LVws which have better edge correction. My Vixen LVWs have noticably better images than my plossls in my 10" F/5.

Those "ripples" you descibe in your 5" are probably baffles inside the tube to combat stray light. Maybe post a pic so we can be certain?

DJVege · #6 21-01-2008, 03:54 PM

Hmm....yeah, I think that must be it. Do I need them in my 10"?

I'll post a pic when I get home tonight.

Cheers!

§AB · #7 21-01-2008, 04:07 PM

I think it's really noticable only at lower powers. With premium eyepices, it'll still be noticable, but not to the same extent. It really depends on your personal tastes - if you can live with it then that's fine but if you find the coma obtrustive then I suggest you invest in a paracorr.

Phil · #8 21-01-2008, 05:58 PM

great stuff DJ
Phil

rmcpb (Rob) · #9 21-01-2008, 06:10 PM

I would not worry about the coma till you give the scope a try as see if it really bugs you. I am changing to more premium eyepieces after quite a while but I have been able to cope with the coma even in my 13" which is f4.5, it has not been nice but at least I could use it.

The ripple in the tube would be a baffle which is not necessary for your 10". To try and increase contrast some people flock their tubes, others set up baffles and others do both its your choice. It is more important in areas of light pollution.

I would recommend you use your scope as it is for a while before you start any mods or accessory purchases except for some collimation tools.

Keep looking up

GrahamL · #10 21-01-2008, 09:41 PM

Coma for me in my 10 "

was never an issue with a 13mm or 7mm nagler
On nights of average to poor seeing the 7 mm was sometimes a little to much power..At low power my 27 panoptic is a fantastic eyepiece that gives pinpoint stars over nearlly all of the fov .. A while back I happened to purchase a 28 mm pretoria eyepiece which corrects for coma at f 4 I think..this is one likeable piece of glass..even at f 5 its pinpoint views right to the edge ..so stupidly I now have 2 low power eyepieces that are both great

As suggested I'd look through your scope before shelling out for a CC
my recollection of a 5 " view of omeg cent compared to the 10" is just
more than a little differant coma or not

DJVege · #11 22-01-2008, 09:05 AM

Thanks guys! Will do!

However looking up and looking up through a scope are two different things! Absolutely no point in observing because my scope doens't seem to look thru clouds!!!!

Very impatiently waiting.....

duncan · #12 22-01-2008, 09:54 AM

Hi DJVege,
I posted about this sort of thing not long back. The title was "Astigmatism" but upon reviewing through the eyepieces it was only annoying through my cheap 32mm eyepiece. The higher power ones nowhere near as bad. My problem up here is not to many people with gear to try other eyepices before buying. So i'll probably splurge on at least one soon enough. It's just deciding which one,LOL

Cheers

edwardsdj (Doug) · #13 22-01-2008, 12:15 PM

Great scope

You must be pleased with your purchase.

Did you get collimation tools?

DJVege · #14 22-01-2008, 12:43 PM

Thanks Duncan, Thanks Doug!

Yeah, I've already got collimation tools (for my 5"). I've got:

* a Cheshire
* A skywatcher newtonian collimation tool
* an Astrosystems barlowed laser collimator

edwardsdj (Doug) · #15 22-01-2008, 12:58 PM

Great set of tools.

When you use the laser, does the collimation change between pointing the telescope horizontally and vertically?

vash (Ashley) · #16 22-01-2008, 01:02 PM

Seeing as how I've had experience with your mount I can say that the 10" scope can go onto it and you can get some nice photo's using it. Though the set up might be better if you use it for planetary imaging with a high power barlow,

DJVege · #17 22-01-2008, 01:20 PM

Yeah? Thanks Vash! I'll probably buy some rings in a few months time and test it out. At least I'll test out the planetary stuff...

Doug, I'll test that tonight and let you know. I've never tested it both horizontally and vertically. Didn't think it would need it.

So, you want me to collimate it horizontally, then check if the collimation holds for the laser in a vertical position?

erick (Eric) · #18 22-01-2008, 01:26 PM

Just swing it up in alt and watch the dot in the laser window. It doesn't move on my 8" and, last night, it appeared to move about a mm on my 12".

edit: in your case, of course, the return shadow on the white surface of the barlowed laser.

edwardsdj (Doug) · #19 22-01-2008, 01:37 PM

I was just wondering if the primary mirror springs were strong enough to accomodate all viewing altitudes.

If they aren't, collimate at approximately the angle you will use most frequently.

erick (Eric) · #20 22-01-2008, 02:50 PM

Quote:

Originally Posted by edwardsdj

I was just wondering if the primary mirror springs were strong enough to accomodate all viewing altitudes.

Yes, in my case the 12" has had stronger springs inserted. The 8" is the original GSO springs but the mirror is relatively light so they seem to be working OK. A 10" with standard GSO springs - perhaps there will be some "give" moving from vertical to horizontal.