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Old 25-06-2017, 07:44 PM
MitchLee (Mitchell)
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Smile Newbie

Greetings all.

Just another newbie introduction - I'm Mitch from Newcastle NSW.

I've been doing photography for a few years now but just recently I've started into the world of astrophotography. Been doing some wide angle shots so far but I'm looking at getting into closer DSO and stellar shots. For that I'm going to need some more gear... so I'm looking at getting an EQ3 or EQ5, preferably with GOTO motors to make it easier for me.

So with that out there, I'll be lurking these forums for a second hand setup as I'm hoping they pop up on a pretty regular basis.

Cheers,
Mitch
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Old 25-06-2017, 07:55 PM
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that_guy (Tony)
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I wouldn't go anything lighter than an HEQ5 for AP. Theres one listed in the classified for sale thats decent price in sydney if you're interested in that. Any ideas on what scope you want to put on the mount?
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Old 26-06-2017, 07:05 AM
MitchLee (Mitchell)
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So the EQ3 isn't sturdy/stable enough for AP?

I'm thinking of a cassegrain style tube at this point. There's an EQ5 GOTO mount with a 150x750 cassegrain on eBay right now for $1500 but it's in Melbourne. Postage would be $200 and I can't inspect it prior to purchase so I'm thinking it could be a gamble for me
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Old 26-06-2017, 09:55 AM
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Lognic04 (Logan)
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AFAIK the eq3 is not sturdy enough, also i'm not sure if you can guide an EQ3. and i recommend you stay away from cassegrains as a beginner in AP! because the focal length is so long you have to guide, but you also have to use an oag which you need a very sensitive cam for. (more money!)
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Old 26-06-2017, 10:59 AM
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pfitzgerald (Paul)
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Hi Mitchell - and welcome to IIS. :-)

I agree with Tony's advice. Don't purchase anything lighter than the HEQ5-Pro. If you have a permanent set up in mind it would be worth considering the EQ6.

I'm in LP Melbourne and have been using a HEQ5-Pro for five years now and am very happy with it. With the aid of PHD and a guide scope I've been able to push it out to 10 minute exposures and still have round stars.

Before making a purchase get onto your nearest astronomy club/society or star party and go and have a look at what other people are using. You will find that the astro community is very inclusive and willing to share knowledge.

Good luck and enjoy the new adventure.

Paul
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Old 27-06-2017, 03:41 PM
cadman342001 (Andy)
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Welcome Mitch ! I'm pretty much in the same position as yourself, and have gone with the HEQ5 Pro.

Andy
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Old 29-06-2017, 11:06 AM
MitchLee (Mitchell)
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Well, it turns out that my brother bought a Newtonian scope about 20 years ago and it has been sitting at my dads place this entire time.

So I went and grabbed it - Not in the greatest condition. Looks like the actual lens has suffered from heat or constant bright light as the coating has flaked off and the lens itself is marked/stained. Looking up into the sky it still works though so that's always a good thing.

Can't really find much on the brand... Optisan Star 900114 II? I'm guessing it's manufacturer is out of business by now. Has a wooden leg tripod with a pretty flimsy accessory plate. Ah well, good place to start anyway!
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Old 29-06-2017, 07:51 PM
Wavytone
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Hi Mitch, welcome to IIS. You mention a cassegrain - you will need to decide what you want to photograph as this plays a significant role in choosing a suitable scope.

For example cassegrains are primarily suited to lunar and planetary targets, at high magnification. Their high focal ratios (typically f/10-f/15) mean they are not good for wide fields, deep-sky stuff (nebulae, galaxies and comets) - for these you need something with a much faster focal ratio, around f/5-f/7.

There are many here on IIS using APO refractors in the range 100-150mm aperture for this, for which they are ideal. Another excellent choice is a Maksutov-Newtonian - Orion and Skywatcher made a few cheap ones around 150-190mm aperture at f/4.5-5.6 depending on which model. And then there are the ones made by Intes Micro.

You can also use a fast Newtonian, anywhere from f/4 to f/6 with a field flattener and coma corrector; budget OTA's around 200-250mm aperture are easy to find.

Also do the maths on sensor size vs focal length, this dictates the field of view.
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Old 30-06-2017, 10:26 AM
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sil (Steve)
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welcome mitch. from what i can tell the scope you picked up is 114mm diameter, 900mm focal length newtonian. certainly a usable beginners scope. I took my first images of juipter and saturn with a webcam through a 114mm celestron scope. As its been sitting a long while its mirror can probably use a clean. Bintel sell a good cleaning liquid that wont effect the mirror coating. its a good scope for you to learn on too and less intimidating than a brand new one youve just paid a grand for. The eyepieces will likely be rubbish and if you get yourself a set of plossals the scope will give you improved views. Don't worry too much if the mirror isnt pristine or has a little rusting, it wont make too much difference at this point for you but also gives you something to practice maintenance on immediately. With newtonians "collimation" is key. Look into it. at the big mirror (the primary) end you'll find three finger screws which adjust the tilt of the primary and if you touch those you can put your viewing out badly quite easily. They are not the screws to remove the mirror for cleaning, those are usually on the side. The secondary mirror also can be adjusted and effects collimation too. Until you've done a bit of research into adjusting primary and secondary mirrors i wouldnt rush into dismantling to clean, it may be tricky to help you reassemble. The mirrors can be adjusted in place and should be able to be removed for cleaning, readjusting after you reassemble. You dont need to buy any tools at this stage, many newbies rush into buying cheap laser collimators off ebay that do a questionable job.

Start by understanding the path light takes in the newtonian, simply light comes in the big open end (yours might have a large cap with a smaller removal central cap in it too) and goes down to the primary mirror which focus and bounces it back up the center of the tube to hit a small round mirror (the secondary) which is angled 45deg to bounce it up the center of the focuser tube. so simple collimation if you take the eyepiece out during day (do this indoors, nowhere near sunlight!) look down the focuser tube and the secondary mirror should look like a circle centered in the focuser tube and you should be able to see the primary reflected in it again perfectly round and centered. For this scope thats pretty much enough to have it colimated. Look it up there are other simple tests you can do using a bright star and eyepiece in the scope.

So this Optical Tube Assembly (OTA), the bit people refer to as the telescope should be perfectly fine for you to use for years to come. Hopefully it has a dovetail plate to attach it to the mount on the wooden tripod, if not you can probably buy one to attach which will let you mount it on a good tripod mount when you get one, EQ5 or EQ6 would suit for years to come. Many people have multiple OTAs (CATs, refractors, reflectors, solar etc) and just use one mount/tripod swapping OTAs depending on the needs. You dont need to buy a full setup for each type, though you can if you have the space and money of course.

Also be aware weight rating on tripod mounts are typically for visual use and you'll get some wobble using an OTA close to that rating. So going for an eq5 or 6 may seem overkill initially but once you catch the bug and want to put more gear on it you'll be thankful you have it, an eq3 will be quick to outgrow as you want something sturdier (and astrophotography demands stability, if you lean that way).

Anyway good luck with it all, I would recommend you grabbing a red dot finder cheap off ebay to put on the OTA even if it has a finderscope. The red dot finders most people find much easier to get the OTA pointed at a specific object. Grab some form of star map (paper, phone, tablet) and maybe a red light torch. These are all essential gear. Invesitgate collimation and maybe cleaning your mirrors (avoid household cleaners besides mild soap and warm water and finish with the bintel cleaning solution. If parts attached to mirrors are rusting paint them with a little wd40 (dont spray, spray into old container and use small brush), just to try to halt rust growth but dont do on mirror it can work underthe metal coating and crack/lift it off the glass. A good beginners set of eyepieces should suit you and the scope well for a long time too. Take it slow and learn, its easy to rush and end up with buyers remorse, find your footing and which direction you want to take your astronomy in.
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Old 30-06-2017, 10:33 AM
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ZeroID (Brent)
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Quote:
Originally Posted by MitchLee View Post
Well, it turns out that my brother bought a Newtonian scope about 20 years ago and it has been sitting at my dads place this entire time.

So I went and grabbed it - Not in the greatest condition. Looks like the actual lens has suffered from heat or constant bright light as the coating has flaked off and the lens itself is marked/stained. Looking up into the sky it still works though so that's always a good thing.

Can't really find much on the brand... Optisan Star 900114 II? I'm guessing it's manufacturer is out of business by now. Has a wooden leg tripod with a pretty flimsy accessory plate. Ah well, good place to start anyway!
Hi Mitch, sounds like about where I started, 114mm ( 4.5") and 900mm Focal Length. F8. Shame the mirror coating seems to be damaged but you'd be surprised how much it may still allow you to see. Mine was in pretty good condition and now look where it got me
I image with a 102mm f7 Lunt. Enough aperture to be useful and lightweight on the EQ6. The other option is the 200mm f5 newt which again makes for a lightweight OTA.
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Old 03-07-2017, 11:16 AM
MitchLee (Mitchell)
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So... the free telescope. It certainly needs a collimation as it is nowhere near lined up at the spider. I've played with it and it's a lot better but not perfect... yet.

The coating on the lens/mirror is kaput. When I say it was 'flaking' earlier, I'm talking about massive 1-2cm in diameter flakes. Tried to clean them up with just water and the rest of the coating came off too. Ah well, these things happen.

Got it out last night and was looking at the moon. Clear images, even if not the most stable of setups. One thing I'm a bit annoyed about however is that it appears it cannot be used for imaging. I've attached my DSLR to the telescope using the T-ring etc and the camera cannot focus no matter what I do... except hold the camera further back from the actual tube and I can grab shots that way but it's not producing a very good end image So, whilst it was free (well not for my brother ) it may not be suitable for what I want
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Old 03-07-2017, 11:04 PM
raymo
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You are lucky, many Newts have the opposite problem; you just need to get an extension tube.
raymo
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