The reflector had all these plus the same lens in the Dobsonian, but at the
same price.

Both telescopes are reflectors. Dobsonian generally just refers to the base, which is generally cheaper than a fully motorised mount as it's usually just made of wood. In fact looking at the specs (200mm diameter, 1000mm focal length) I think they are the same telescope. Maybe some of the accessories are different but I can't tell from the specs - for example you'd want a telescope with a Crayford focuser for better precision, etc.

You can buy an 8" Dobsonian for abour $500 (from Bintel for example). The EQ5 version would set you back about $1K, so I'm surprised you found it for $689, so you'll have to post a link to the place you are looking at buying from so we can see what accessories are included and the specs.

Depending on how often you wish to use the telescope and for what purpose you may or may not be happy with the dobsonian in the end. If you're after planetary viewing, the dobsonian base will get extremely frustrating as not only will your object go out of view but the wood mount has heaps of friction so it's hard to centre your object well without the object bouncing around in view. For astrophotography forget the Dob.

However in my opinion the EQ5 isn't good enough to hold an 8" reflector without flailing around in the wind - terrible for astrophotography. An EQ6 or similar would do a much better job for that.

I started off with an 8" Dob, messed around with it for a few weeks looking at everything. When I decided to pursue the hobby further I went and got an EQ6 - the classic version with just dumb tracking but no guiding. This made astrophotography possible and kept me going for a while. However I regret not paying a little more for the guided version of the mount, as it's annoying having to precisely align the mount each night (1-2 hours of work!) and even then your object still drifts due to mechanical imperfections. There are upgrade kits for the mount to make it guided, but they cost >70% of the price of the mount, compared to an extra 30% or so if you buy the upgraded version upfront.

If you have any other questions, or want to see shots that are possible with a telescope of that size let us know.

last edited by parabol at 15:10:52 16/Jan/12

One of my mates does astrophotography with a William Optics 132 mm aperture telescope on an EQ6 equatorial tracking mount, which I assume is pretty high-end gear - he takes it pretty seriously; I can prolly pass on some questions in the massively unlikely event parabol can't answer anything. I'll ask him about this rig and see if he has any thoughts.

Sorry to double post, I also got the price for a EQ6. $999 But I'm also questioning that... I'll get back to you once opening hours start again. I'd link the site, but they don't list prices :/

Would you advise that I should wait a bit longer and fork out the extra?

Going by say Bintel's prices, the telescope itself (no mount) is $450, with a similar Dob version (though f/6 primary) being $500, which means the Dob mount itself is about $50. Not bad for starting off with and it should give you a few weeks to play around with the telescope to see what kind of objects you REALLY want to see after trying out a bit of everything.

I also got the price for a EQ6. $999 But I'm also questioning that.

Very unlikely to be the GOTO (i.e. guided) version - probably the 'classic' version that I have that is tracking-only. Basically you turn it on and it simply rotates roughly with the earth - no feedback to make it lock onto anything.

Would you advise that I should wait a bit longer and fork out the extra?

Given the Dob base will only cost you an extra $50, I see no problem with getting the Dob version to begin with. Plus the dob base acts as a good stand for when the scope isn't on a GOTO mount.

However, for seeing stellar/galactic stuff a lower focal-length scope might be better. Something at 600mm or below, such as famous ED80 refractor. It's also better for viewing the moon and many nebulae. For raw planetary viewing, you'll need a focal length of at least 2000mm, meaning the reflector with barlow lenses are a better choice. Many people have a reflector for the high mirror diameter at an affordable cost for raw light-gathering ability of faint or highly magnified objects, and a smaller refractor when high magnification isn't needed.

Also, having a laptop around helps immensely. I usually have Stellarium installed and running in night-mode to maintain my night vision. Was able to predict Pluto's exact location with it, so it's fairly accurate.

last edited by parabol at 19:53:30 16/Jan/12

How much extra is that?

At the time I bought my mount it was $1300 for the dumb version and $2K for the guided version. The newer and physically stronger GOTO model (can take heavier telescopes) is around $1800 now.

So the guided version has smarts to lock on to something in the sky and follow it? How much extra is that?

It's a bit complicated, but here goes ...

Basically with the dumb version, there's a paddle controller (see pic below). For example you point the mount towards the south celestial pole (which is a point in space an infinite distance away that the south pole is pointed at) and hit S, and the motors will rotate the mount in right-ascension - i.e. the axis the mount is pointed at. Think of it as tracing a circle around a south celestial pole point in the sky. Unless you spend a couple of hours watching stars drift and make adjustments to the direction the mount is facing, the rotation will be off.

The GOTO mount has a different hand-controller - it's actually computerised with an LCD or other screen. You can do simple star-alignment - at the start of your session point the telescope towards 3 stars that you specify to the software and it will make an internal map of the sky and know what speed to activate the motors of both axes to track the rotation of the earth in both axes even if your mount isn't physically lined up perfectly. This achieves reasonable results - the software can only do so much guesswork without a constant feedback loop, which leads to ...

If you have a smaller second telescope (guiding scope) mounted on top of your main one and hook up a webcam to it, clever software can track a star and tell the mount which way to make micro-adjustments to keep the star aligned. Though often you don't care about the actual star, you just want the mount to track the earth's rotation accurately while you're looking at something else with the main telescope (e.g. Jupiter).

To make it even more interesting, rather than having two telescopes there are some mirrors that you can place in the path of your main telescope that steal a bit of the edge of the view (that normally does not reach your regular astrophotography CCD anyway) and send it to the webcam for guiding purposes.



last edited by parabol at 22:40:46 16/Jan/12

Also, I'm a student so I'd rather this last me longer than a few weeks before I'd need to get another telescope

Hang on a sec! Do you mean buying one with a different mount or switching between reflector and refractor? Cause with the mount: if/when you want to upgrade to an equatorial motorised mount down the track, simply buy mounting rings, take off the knobs/spring on the sides of the telescope tube holding it to the Dob base, detach and place the telescope on your motorised mount. I store my telescope on the Dob base, set up the mount outside and then transfer the tube to it from the wooden base. At the end of the session, telescope goes back onto the Dob base for storage.

Dumb question: Can you see anything in suburban areas? I'm assuming the moon and that would be it?

I rarely look at the moon to be honest, can see much more:

Jupiter: http://photos.smugmug.com/photos/680362018_2wDtK-O.gif
Saturn: http://photos.smugmug.com/photos/463907120_oNaKR-O-4.jpg

Done with my scope, EQ6, a specific webcam and lots of trial/error and processing. If you want to do long exposures (several hours), then you'd want to be at a dark site - but it'll take you years to have that level of competency and have the right equipment to do it (I have neither). Go visit the IIS forum to see what people are producing from their suburban backyards.

last edited by parabol at 11:19:37 17/Jan/12

Wait, are you saying I can buy a dob, then just replace the base?

When you buy a Dob you get the telescope tube and Dob mount in separate boxes - you don't need to use the Dob mount if you don't want to. If you do you screw two knobs onto the sides of the tube, place tube onto Dob base and stretch a spring from knob to base to keep them together. The tube then rotates around the contact point (usually a teflon surface for smooth movements) to point up/down.

Here's a pic: http://www.telescopedobsonian.com/images/dob-base.jpg

To motorise the setup, get rid of the springs/knob so that the tube is naked, get some tube rings (see pic link below), remove tube from Dob base, attach rings to tube and pop it onto your motorised mount.

http://www.telescope-service.com/OrionUSApics/imaging/TSLeitrohrschellen.jpg

My telescope started as a Dob and now spends most of its time on an EQ6 during viewing.

last edited by parabol at 12:52:10 17/Jan/12

Woah ok. So for example, If I bought: http://www.bintel.com.au/Telescopes/Dobsonian/Bintel-BT202-B-8--Dobsonian/72/productview.aspx

My Dob is the previous model. Good starter scope.

or: http://www.bintel.com.au/Mounts---Tripods/EQ-Mounts/Skywatcher-EQ3-Pro-GoTo-Mount/93/productview.aspx

Highly advise against an EQ3 for an 8" reflector. You'll exceed the maximum load capacity of the EQ3, meaning assuming the mount doesn't break, tip over, or give up trying to rotate the telescope, the scope will be wobbling with the slightest wind.

then at a later stage, either get: http://www.bintel.com.au/Mounts---Tripods/EQ-Mounts/Skywatcher-EQ5-Mount/94/productview.aspx

Better than the EQ3, but may be cutting it close to the maximum load capacity (you want to load at 50-80% of the quoted maximum load for good stability). I'd suggest doing more research to find out if the two will work well together. Also keep in mind that's the dumb version of the mount. No star alignment and no guiding, meaning all you can do is manually align the mount and hope for the best.

The GOTO version of the EQ6 is recommended (called the NEQ6 Pro now I believe), but obviously costs some more: $1699 now - http://www.andrewscom.com.au/site-content-section-10-skywatcher.htm

I'd say grab the Dob, play around with it and do some research to determine where you want to go from there and how much you're willing to invest then. It's a fairly expensive hobby, but well worth it if you're patient, do your research and try to minimise money wastage (e.g. avoid buying a non-GOTO mount and realising you want to upgrade to GOTO but it costs more to upgrade than having bought GOTO upfront).

Is the maximum weight calculated through full extension? Like, could I get away with not extra extending the tripod out for more
stability and more load?

It could be a combination of what the motors can handle for rotation, what the tripod legs themselves can handle, and what the mount head (the heaviest part of the mount that attaches to the top of the tripod) can support.

If you're going to:

a) mount extra gear: webcam or extra adapters or extra piggy-back scope
OR
b) do any deep-space imaging

.. then you'd want a stronger mount like the NEQ6 for the stability. Nothing like wobble while you're peering through the scope or smeared images to ruin the experience. To be honest I think if all you're doing is observing by eye with no other equipment, the EQ5 -should- be fine - the GOTO version that is, don't see the point in the dumb version as it makes the experience fairly annoying.

edit: would you also recommend purchasing through bintel? Through them, I save $200 alone. Although I don't know about other stores yet

I got my Dob through Bintel. Andrews (which I linked to in my earlier post) has some items for cheaper. There is also MyAstroShop (can google that) where I got my mount from. Just shop around and make sure to compare the specs of whatever you buy, as one retailer might have different features or extras for a similar sounding product. Comparing the model number isn't enough.

Still I'd recommend just trying out the Dob before splashing out on anything else (mounts, cameras, etc), to find out if you like the hobby enough in the long-term and what your interests are. I started off thinking I'd take shots of the moon but got extremely bored with that and moved onto planetary and then onto deep-space long-exposure photography - which required very different equipment to what I originally predicted.