not-so-newbie looking for the "perfect" weeknight scope

[janoskiss]

I have two scopes that I use at the moment: the Saxon ED80 and the GSO Dob 200mm/8".

When I go away for a night of dark sky observing, the ED80 does not get much of a look through. But at home the ED80 is getting a lot more use than the Dob. This is partly because I can use the ED80 instantly without waiting for cooldown, but more importantly that even if I do wait for the Dob to cool down (for up to 2 hours), it never comes close to the refractor on "seeing". After having seen Bird's demonstrations of how small temperature differences can affect what you see through the EP, I'm thinking maybe my Dob never reaches thermal equilibrium with the surrounding air. So, for medium to large aperture viewing I want an active cooling system like Bird's. :D

But for use at home on weeknights I think I might be better served by something that works perfectly without batteries or any other power source. Now, my ED80 exceeded all my expectations for an 80mm aperture scope. But since most of my light-polluted backyard observation is aimed at the planets, I find the aperture a somewhat lacking in light gathering power at high magnifications. So I'm thinking of maybe upgrading to the ED100 (Saxon/Orion/etc) or some other similar scope.

I don't recall seeing any ED100 owners on these forums. And reviews are hard to come by. The ED80 seems to far outsell the ED100 everywhere. I'd hate to sell my ED80 to finance an ED100 (worth two ED80s), only to find out the ED100 is just not up to the standard of the ED80.

Do you have some experience with the ED100? Or do you know of a similarly priced apo or semi-apo 100+mm refractors around? Or do you have advice on what is a good weeknight backyard scope? Or do you just want to knock some sense into me after reading all this drivel? I'd love to hear from you.

:)

[Iddon]

G'day Janoskiss of the censored title - I can't help you with the 100mm advice - but I can help you with that 80mm when it becomes surplus to requirements :):)

[Miaplacidus]

You sure you're not using that ED80 so much because it weighs a helluva lot less than your dob? I don't know much about the ED100, but I think I know that refractors get heavy quite quickly once you increase the aperture.

Maybe try hefting an ED100 before you decide. (Just a thought.)

Good luck!

Brian.

[janoskiss]

Brian, it's not the portability. I put two handles on the Dob base, and the 8" Dob is a lot easier to move than the ED80 with the EQ5 + counterweight. I checked the weight of the ED100 and it is less than 1kg more than the ED80. Insignificant, considering the weight of the mount it'll be sitting on.

[dhumpie]

Have you ever though of using your EQ mount alt-az? Then you could do away with the counterweights and the whole setup would be much easier to use and carry. Alternatively get a lighter EQ mount for the 80ED. There have been some discussions on these in the past. Personally I use my Orion 80ST on photo tripod heaps. I also have a C6 Celestron/Vixen on an EQ3 clone mount and a 102mm f/5 Synta refractor and between them all, the 102mm gets used the least (it shares the mount with the C6 and when either one of them are on it, it is just one trip to the backyard!). Its just that I don't see a big difference in what you can see between an 80mm and a 102mm so I don't think it is worth the upgarde. Just my 2 cents.

Darren

[Stu]

So what you want is something bigger than the ED80 but you're too impatient for a dob?
Umm... I can relate to that, but I was thinking the same thing as you!! ED100!!

Luckly I haven't grown out of my 80mm just yet, so I'll let you buy the ED100 first.:P

In all seriousness, what you just discribed is a Maksutov. Dave47Tuc just bought an Intes 150mm. I looked thought it last night and was pretty good. Had only been set up in the backyard for half an hour before I got there. Mars looked good. You will find that even though it still has to cool down, there are not many tube currents because it's still a small scope and the optics are sealed.

[janoskiss]

It's not about impatience, because the Dob never gets there. I'd be willing to wait a specified length of time, be that 15 mins or 2 hours, if it meant nice steady images at the EP. But the Dob rarely delivers. So I opt for a large-ish (3-5") refractor, or a small-ish (6-10") Dob with "Bird"-style active cooling, for home use.

[Striker]

Steve,

A short discussion on cloudy nights about both the ED80 and ED100
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/1,2,3,4,5,8,9,10/Number/262596/Main/262144

[Dave47tuc]

Steve,
I'm not really sure what your looking for here. :confuse3: To me it seems that you want to see things a little better than the 80 mm will give you.
Your 8" Dob will do that, but you have never seemed that happy with it.

What about a 8" sct tube on your EQ5 mount!!! :shrug: It would be better than a 100mm and the EQ mount will hold the short tube ok for viewing.
Dew will be a problem but a flexishield can fix that. You have a diagonal etc, so you just need the tube and dovetail plate. :)
I came close to doing the exact thing, but found the Mak instead. ;)

[janoskiss]

Thanks Dave. Never considered an SCT or MCT a viable option, but I suppose, why not. I've never looked through one before though, except for Xtreme John's Meade.

The Dob just doesn't perform on demand even after having been outside for an hour. I'm sure it's a problem of cooling. The scope is stored in pretty much the warmest spot in the house (no room anywhere else).

How much of a problem is cooling with the closed tube designs of SCTs or MCTs? And what's the advantage of SCT over MCT and vice versa? :confuse3:

PS. I should remove the "not-so-" from the thread title at this point.

[Dave47tuc]

Steve,
The sct and mak will give you a larger image scale due to there longer FL .
Cooling can be a problem and I can't comment on the Mak to much as i only just got it. With my sct I had I never really found this a problem. But going from a warm room to cool outside the sct will not preform as well till it cooled.
One big advantage Mak's and Sct's have is the large F ratio and FL.
This tends to using 25 - 10 mm eyepieces for high power.
Also cheap Ep's work well. But you have great Ep's so no problem thier.
Do some research on the net re the mak and sct on the eq 5 mount. I think you maybe happy with that sort of combination.
As for grab and go my set up is ideal for it. You can put a sct on your mount and it will be a good grab and go also. :)

[bird]

Hi Steve, you'll find that a closed tube like SCT will take even longer to cool than your dob, so that may not be what you're looking for. How these scopes perform on temperature will depend on your local conditions.

I've seen through a local guys ED100 and it looks very nice. Not sure how much of an improvement over the ED80, but it's about 50% more area so it should be noticeable.

regards, Bird

[Starkler]

Perhaps you just need a nice cooling fan arrangement on the dob and a little bit of patience to set up and leave it running outside for 30 min before observing?

[ving]

after reading all this that was my thought too geoff. get a fan or 2 happening. :confuse3:

[gbeal]

While some folk have had issues with cooling, I have what could be termed a vast expereince with Maksutovs, and love them.
There is no way that I would buy a 4" ED (or apo), in preference to something like the Intes Micro M503. Houghy has one. They are simply stunning, and will give most any 4" apo a run, and some.
Maybe if you are reasonably close to Houghy, take a look at his.

[bird]

Well, you *do* live in a climate that's about 5 degrees C all year round... :poke: :poke: :lol:

[gbeal]

5°? You gotta be joking. OK it may get that low tonight, but it is about 23 at the moment.

[bird]

Ahhh, sounds just like Canberra...

Bird

[gbeal]

Yep, maybe, but I wish I could get the sort of seeing you got recently with that Ballarat Mars, awesome.

[bobcdyne]

I am new to this and having some difficulty. I figure "Mak" is Maksutov. What is "Sct"
and what is the "Intes Micro M503".

[gbeal]

Sorry Bob.
Mak is indeed "Maksutov", and they come in a couple of popular flavours. Maksutov Cassegrain, and Maksutov Newton. Both are reputed to be excellent.
"SCT" is Schmidt Cassegrain Telescope, Meade & Celestron and others produce them, and again they are good scopes.
Intes Micro is a Maksutov (both) manufacturer, in Russia, and the Intes Micro M503 is a 5" Maksutov Cassegrain, f10 scope.

[janoskiss]

Welcome bobcdyne. Check out this page for some basic info on scope designs:
http://www.celestron.com/tb-2ref.htm

... here's another:
http://www.ayton.id.au/gary/Science/Astronomy/Ast_Telescope_Types.htm

[bird]

gary, a 5" scope won't suffer too much from thermal problems, sorry I didn't pick that up in your comment earlier, I'm not familiar with those model numbers. It's probably got a small enough mass in the mirror to act similar to a 4" or 5" refractor.

regards, Bird

[janoskiss]

First of all I'll be getting the fan and battery for the Dob and a couple of temperature sensors to see what's really going on.

Where do I find one of these Intes scopes for sale in Australia? Anyone know how the Synta/Saxon/Orion Maks compare? (I assume they're cheaper. :shrug: )

[gbeal]

Bird,
I still think the refractor will cool to ambient better, but the smaller Maks seem to give very good views.
I had an M503 for a while, but it semed to also play second fiddle to the MN76, nothing beats aperture I suppose.
Janokiss, the Intes Micro products will have to be imported, but I can recommend a very good dealer. Yes they will cost more, and in places, significantly more, than the cheaper brands. I have certainly read good reports about some of the cheaper models, it really just depends what you want.

[Robert_T]

Hi Steve, there's quite a few reviews of Intes Maksutovs on cloudy nights http://www.cloudynights.com/ mainly 6 in versions though. Astronomy and Electronics Centre in Cleve SA import and sell these.

cheers,

[Dave47tuc]

Claude does not sell Intes anymore. I emailed him about my MK-67 and his reply was "sorry we don't carry those scopes anymore" :)

I put my scope against a Tak FS 128 last night. Who won :confuse3:
The seeing and rain did. But the hour we got in my Mak kept up very well.